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1.
  • Abbott, D. Wade, et al. (författare)
  • Seaweed and Seaweed Bioactives for Mitigation of Enteric Methane : Challenges and Opportunities
  • 2020
  • Ingår i: Animals. - : MDPI AG. - 2076-2615. ; 10:12
  • Forskningsöversikt (refereegranskat)abstract
    • Simple Summary The need to become more efficient in agriculture and the food industry exists parallel to the challenge of climate change. Meat and dairy production is the target of much scrutiny due to methane (CH4) emissions and global warming. On the other hand, it should be noted that two-thirds of the world's agricultural land consists of pastures and permanent grasslands and is used for livestock grazing. This land is predominantly unsuitable for arable purposes but facilitates the production of high-quality human-edible protein in the form of ruminant animal-derived meat and milk. This makes a significant contribution to feeding the world's population. There is a need to reduce CH4 emissions, however, and several approaches are being researched currently. Seaweeds are diverse plants containing bioactives that differ from their terrestrial counterparts and they are increasingly under investigation as a feed supplement for the mitigation of enteric CH4. Seaweeds are rich in bioactives including proteins, carbohydrates and to a lesser extent lipids, saponins, alkaloids and peptides. These bioactives could also play a role as feed ingredients to reduce enteric CH4. This review collates information on seaweeds and seaweed bioactives and their potential to impact on enteric CH4 emissions. Seaweeds contain a myriad of nutrients and bioactives including proteins, carbohydrates and to a lesser extent lipids as well as small molecules including peptides, saponins, alkaloids and pigments. The bioactive bromoform found in the red seaweed Asparagopsis taxiformis has been identified as an agent that can reduce enteric CH4 production from livestock significantly. However, sustainable supply of this seaweed is a problem and there are some concerns over its sustainable production and potential negative environmental impacts on the ozone layer and the health impacts of bromoform. This review collates information on seaweeds and seaweed bioactives and the documented impact on CH4 emissions in vitro and in vivo as well as associated environmental, economic and health impacts.
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3.
  • Cabezas Garcia, Edward Hernando, et al. (författare)
  • Between-cow variation in digestion and rumen fermentation variables associated with methane production
  • 2017
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 100, s. 4409-4424
  • Tidskriftsartikel (refereegranskat)abstract
    • A meta-analysis based on an individual-cow data set was conducted to investigate the effects of between-cow variation and related animal variables on predicted CH4 emissions from dairy cows. Data were taken from 40 change-over studies consisting of a total of 637 cow/period observations. Animal production and rumen fermentation characteristics were measured for 154 diets in 40 studies; diet digestibility was measured for 135 diets in 34 studies, and ruminal digestion kinetics was measured for 56 diets in 15 studies. The experimental diets were based on grass silage, with cereal grains or by-products as energy supplements, and soybean or canola meal as protein supplements. Average forage:concentrate ratio across all diets on a dry matter basis was 59:41. Methane production was predicted from apparently fermented substrate using stoichiometric principles. Data were analyzed by mixed-model regression using diet and period within experiment as random effects, thereby allowing the effect of experiment, diet, and period to be excluded. Dry matter intake and milk yield were more repeatable experimental measures than rumen fermentation, nutrient outflow, diet digestibility, or estimated CH4 yield. Between-cow coefficient of variation (CV) was 0.010 for stoichiometric CH4 per mol of volatile fatty acids and 0.067 for predicted CH4 yield (CH4/dry matter intake). Organic matter digestibility (OMD) also displayed little between-cow variation (CV = 0.013), indicating that between-cow variation in diet digestibility and rumen fermentation pattern do not markedly contribute to between cow-variation in CH4 yield. Digesta passage rate was much more variable (CV = 0.08) between cows than OMD or rumen fermentation pattern. Increased digesta passage rate is associated with improved energetic efficiency of microbial N synthesis, which partitions fermented substrate from volatile fatty acids and gases to microbial cells that are more reduced than fermented carbohydrates. Positive relationships were observed between CH4 per mol of volatile fatty acids versus OMD and rumen ammonia N concentration versus OMD; and negative relationships between the efficiency of microbial N synthesis versus OMD and digesta passage rate versus OMD, suggesting that the effects of these variables on CH4 yield were additive. It can be concluded that variations in OMD and efficiency in microbial N synthesis resulting from variations in digesta passage contribute more to between-animal variation in CH4 emissions than rumen fermentation pattern.
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4.
  • Cabezas Garcia, Edward Hernando, et al. (författare)
  • Effects of replacement of late-harvested grass silage and barley with early-harvested silage on milk production and methane emissions
  • 2017
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 100, s. 5228-5240
  • Tidskriftsartikel (refereegranskat)abstract
    • This study evaluated the effects of gradual replacement of a mixture of late-cut grass silage (LS) and barley with early-cut grass silage (ES) on milk production, CH4 emissions, and N utilization in Swedish Red cows. Two grass silages were prepared from the same primary growth of timothy grass sward but harvested 2 wk apart [11.0 and 9.7 MJ of metabolizable energy/kg of dry matter (DM)]. Four diets, fed as a total mixed ration, were formulated to meet the metabolizable energy and protein requirements of 35 kg of energy-corrected milk (ECM) by gradually replacing a mixture of LS and barley with ES (0, 33, 67, and 100% of the forage component of the diet), whereas the proportion of barley decreased from 47.2 to 26.6% of diet DM. Expeller canola meal was used as a protein supplement. Sixteen Swedish Red cows were used in 4 replicated 4 x 4 Latin squares. Cows were offered diets ad libitum and milked twice daily. Each period of 28 d comprised 14 d of diet adaptation followed by 14 d of data collection. Intake and milk yield were recorded daily, and milk samples were collected on d 19 to 21 and d 26 to 28 of each period. Diet digestibility was determined by grab sampling using indigestible neutral detergent fiber as an internal marker. Gas emissions were measured using the Green Feed system (C-Lock Inc., Rapid City, SD). Dry matter intake (DMI) linearly decreased from 22.6 to 19.3 kg/d as the proportion of ES increased in the diet. The ECM yield did not differ among treatments, but milk protein yield decreased with increasing proportion of ES in the diet. Because of reduced DMI with increasing ES, feed efficiency (ECM/DMI) improved with an increased proportion of ES in the diet. Nitrogen efficiency (milk N/N intake) did not change despite a linear increase in milk urea N concentration from 9.7 (LS alone) to 11.9 mg/dL (ES alone) with graded replacement of LS and barley by ES in the diet. Lower DMI responses in ES diets were partly compensated for by increased organic matter digestibility (656 g/kg of DM for LS alone; 715 g/kg of DM for ES alone) related to improved forage digestibility at early harvesting. Total CH4 emissions and CH4 intensity (CH4/ECM) were not influenced by diet, but CH4 yield (CH4/DMI) increased linearly from 19.5 to 23.0 g/kg of DMI with greater inclusion of ES in the diet. In conclusion, replacing LS and barley with ES improved the conversion of feed to milk without increasing CH4 emissions or compromising N efficiency.
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5.
  • Cabezas Garcia, Edward Hernando, et al. (författare)
  • Effects of replacement of late-harvested grass silage and barley with early-harvested silage on ruminal digestion efficiency in lactating dairy cows
  • 2018
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 101, s. 1177-1189
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this experiment was to quantify the effects of graded replacement of late-harvested grass silage and barley with early-harvested silage on nutrient digestion and rumen fermentation. Four experimental diets were fed to 4 multiparous rumen-cannulated Nordic Red cows in 4 x 4 Latin square design with 21-d periods. Dietary treatments consisted of late-cut grass silage (LS) and rolled barley, which was gradually replaced with early-cut grass silage [ES; 0, 33, 67, and 100% of the forage component (ES + LS) of the diet]. With increased proportion of ES in the diet, the proportion of barley decreased from 47.2 to 26.6% on a dry matter basis. Early-and late-cut silages were harvested at 2-wk intervals (predicted concentrations of metabolizable energy 11.0 and 9.7 MJ/kg of dry matter). The 4 diets were formulated to support the same milk production. Nutrient flows were quantified using omasal sampling technique applying the triple-marker method (Cr, Yb, and indigestible neutral detergent fiber) and N-15 as a microbial marker. Feed intake decreased with graded replacement of LS and barley with ES, but milk production was not influenced by diet. Digestibility of nutrients improved with graded addition of ES in the diet with the greatest difference observed in digestibility of neutral detergent fiber (NDF) and potentially digestible NDF (pdNDF). The results suggested that improved cell wall digestibility with graded level of ES in the diet was partly related to higher intrinsic digestibility of ES than LS, and partly due to negative associative effects with an increased proportion of LS and barley in the diet. Efficiency of microbial N synthesis was not influenced by the diet, but ruminal protein degradability increased with ES in the diet. Rumen fermentation pattern was not affected by the diet despite large difference in the profile of dietary carbohydrates. Rumen pool size of NDF and pdNDF, and ruminal turnover time of NDF decreased with graded addition of ES in the diet, whereas digestion rate of pdNDF improved. The results of this study indicate that increased CH4 yield in a parallel production study with graded addition of ES in the diet were more related to greater ruminal and total digestibility of organic matter than to the changes in rumen fermentation pattern.
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6.
  • Chagas, Juana, et al. (författare)
  • Effect of a Low-Methane Diet on Performance and Microbiome in Lactating Dairy Cows Accounting for Individual Pre-Trial Methane Emissions
  • 2021
  • Ingår i: Animals. - : MDPI AG. - 2076-2615. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • Simple Summary Low methane-emitting dietary ingredients have been identified in extensive research conducted during the past decade. This study investigated the effects of replacing grass silage with maize silage, with or without rapeseed oil supplementation, on the methane emissions and performance of dairy cows. Pre-trial measurements of methane-emissions were used in the evaluation. Partial replacement of grass silage with maize silage did not affect methane emissions but reduced dairy cow performance. Adding rapeseed oil to the diet substantially reduced methane emissions due to modified rumen microbiota, resulting in impaired nutrient intake, digestibility, and yield of energy-corrected milk. Correcting for individual cow characteristics of methane emissions did not affect the magnitude of suppression of methane emissions by dietary treatments. This study examined the effects of partly replacing grass silage (GS) with maize silage (MS), with or without rapeseed oil (RSO) supplementation, on methane (CH4) emissions, production performance, and rumen microbiome in the diets of lactating dairy cows. The effect of individual pre-trial CH4-emitting characteristics on dietary emissions mitigation was also examined. Twenty Nordic Red cows at 71 +/- 37.2 (mean +/- SD) days in milk were assigned to a replicated 4 x 4 Latin square design with four dietary treatments (GS, GS supplemented with RSO, GS plus MS, GS plus MS supplemented with RSO) applied in a 2 x 2 factorial arrangement. Partial replacement of GS with MS decreased the intake of dry matter (DM) and nutrients, milk production, yield of milk components, and general nutrient digestibility. Supplementation with RSO decreased the intake of DM and nutrients, energy-corrected milk yield, composition and yield of milk fat and protein, and general digestibility of nutrients, except for crude protein. Individual cow pre-trial measurements of CH4-emitting characteristics had a significant influence on gas emissions but did not alter the magnitude of CH4 emissions. Dietary RSO decreased daily CH4, yield, and intensity. It also increased the relative abundance of rumen Methanosphaera and Succinivibrionaceae and decreased that of Bifidobacteriaceae. There were no effects of dietary MS on CH4 emissions in this study, but supplementation with 41 g RSO/kg of DM reduced daily CH4 emissions from lactating dairy cows by 22.5%.
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7.
  • Chagas, Juana, et al. (författare)
  • In Vitro Evaluation of Different Dietary Methane Mitigation Strategies
  • 2019
  • Ingår i: Animals. - : MDPI AG. - 2076-2615. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • Simple Summary Dietary methane mitigation strategies do not necessarily make food production from ruminants more energy-efficient, but reducing methane (CH4) in the atmosphere immediately slows down global warming, helping to keep it within 2 degrees C above the pre-industrial baseline. There is no single most efficient strategy for mitigating enteric CH4 production from domestic ruminants on forage-based diets. This study assessed a wide variety of dietary CH4 mitigation strategies in the laboratory, to provide background for future studies with live animals on the efficiency and feasibility of dietary manipulation strategies to reduce CH4 production. Among different chemical and plant-derived inhibitors and potential CH4-reducing diets assessed, inclusion of the natural antimethanogenic macroalga Asparagopsis taxiformis showed the strongest, and dose-dependent, CH4 mitigating effect, with the least impact on rumen fermentation parameters. Thus, applying Asparagopsis taxiformis at a low daily dose was the best potential dietary mitigation strategy tested, with promising long-term effects, and should be further studied in diets for lactating dairy cows.Abstract We assessed and ranked different dietary strategies for mitigating methane (CH4) emissions and other fermentation parameters, using an automated gas system in two in vitro experiments. In experiment 1, a wide range of dietary CH4 mitigation strategies was tested. In experiment 2, the two most promising CH4 inhibitory compounds from experiment 1 were tested in a dose-response study. In experiment 1, the chemical compounds 2-nitroethanol, nitrate, propynoic acid, p-coumaric acid, bromoform, and Asparagopsis taxiformis (AT) decreased predicted in vivo CH4 production (1.30, 21.3, 13.9, 24.2, 2.00, and 0.20 mL/g DM, respectively) compared with the control diet (38.7 mL/g DM). The 2-nitroethanol and AT treatments had lower molar proportions of acetate and higher molar proportions of propionate and butyrate compared with the control diet. In experiment 2, predicted in vivo CH4 production decreased curvilinearly, molar proportions of acetate decreased, and propionate and butyrate proportions increased curvilinearly with increased levels of AT and 2-nitroethanol. Thus 2-nitroethanol and AT were the most efficient strategies to reduce CH4 emissions in vitro, and AT inclusion additionally showed a strong dose-dependent CH4 mitigating effect, with the least impact on rumen fermentation parameters.
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8.
  • Chagas, Juana, et al. (författare)
  • Modelling the impact of the macroalgae Asparagopsis taxiformis on rumen microbial fermentation and methane production
  • 2021
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Background The red macroalgae Asparagopsis taxiformis is a potent natural supplement for reducing methane production from cattle. A. taxiformis contains several anti-methanogenic compounds including bromoform that inhibits directly methanogenesis. The positive and adverse effects of A. taxiformis on the rumen microbiota are dose-dependent and operate in a dynamic fashion. It is therefore key to characterize the dynamic response of the rumen microbial fermentation for identifying optimal conditions on the use of A. taxiformis as a dietary supplement for methane mitigation. Accordingly, the objective of this work was to model the effect of A. taxiformis supplementation on the rumen microbial fermentation under in vitro conditions. We adapted a published mathematical model of rumen microbial fermentation to account for A. taxiformis supplementation. We modelled the impact of A. taxiformis on the fermentation and methane production by two mechanisms, namely (i) direct inhibition of the growth rate of methanogens by bromoform and (ii) hydrogen control on sugars utilization and on the flux allocation towards volatile fatty acids production. We calibrated our model using a multi-experiment estimation approach that integrated experimental data with six macroalgae supplementation levels from a published in vitro study assessing the dose-response impact of A. taxiformis on rumen fermentation.Results our model captured satisfactorily the effect of A. taxiformis on the dynamic profile of rumen microbial fermentation for the six supplementation levels of A. taxiformis with an average determination coefficient of 0.88 and an average coefficient of variation of the root mean squared error of 15.2% for acetate, butyrate, propionate, ammonia and methane.Conclusions our results indicated the potential of our model as prediction tool for assessing the impact of additives such as seaweeds on the rumen microbial fermentation and methane production in vitro. Additional dynamic data on hydrogen and bromoform are required to validate our model structure and look for model structure improvements. We expect this model development can be useful to help the design of sustainable nutritional strategies promoting healthy rumen function and low environmental footprint.
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9.
  • De Oliveira Franco, Marcia, et al. (författare)
  • In vitro evaluation of agro-industrial by-products replacing soybean meal in two different basal diets for ruminants
  • 2017
  • Ingår i: Rapport / Sveriges lantbruksuniversitet, Institutionen för husdjurens utfodring och vård. - 0347-9838. ; , s. 54-59
  • Konferensbidrag (refereegranskat)abstract
    • Large number of by-products from the agricultural industry can potentially be used as protein sources in diets to dairy cows. The increasing demand for alternative dietary protein supplements in ruminant production systems is due to a growing requirement for a more sustainable food production from the livestock industry. However, use of agro-industrial byproducts in diets to dairy cows and beef cattle have to be efficient in terms of nutrient utilization, be complementary to basal feed ingredients and not impair production. Since in vivo studies are very expensive and laborious, using an in vitro gas production technique enables identification of by-products which can efficiently replace conventional ingredients. Recently, there has been great progress in the development of the automated gas in vitro technique, which enables treatment evaluation of ruminal fermentation profiles, diet digestion rates (Huhtanen et al., 2008), methane (CH4) production (Ramin and Huhtanen, 2012) and estimation of utilizable crude protein (uCP; Edmunds et al., 2012). The aim of this study was to evaluate effects of levels of agro-industrial by-products replacing soybean meal in diets based on silage and barley or beet fibre on neutral detergent fibre (NDF) digestibility, true organic matter (OM) digestibility, uCP, fermentation parameters and CH4 production in vitro.
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  • Fatehi, Farhang, et al. (författare)
  • A comparison of ruminal or reticular digesta sampling as an alternative to sampling from the omasum of lactating dairy cows
  • 2015
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 3274-3283
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this study was to develop and compare techniques for determining nutrient flow based on digesta samples collected from the reticulum or rumen of lactating dairy cows with estimates generated by the omasal sampling technique. Pre-experimental method development suggested, after comparing with the particle size distribution of feces, application of primary sieving of ruminal and reticular digesta from lactating cows through an 11.6-mm sieve, implying that digesta particles smaller than this were eligible to flow out of the rumen. For flow measurements at the different sampling sites 4 multiparous, lactating Nordic Red cows fitted with ruminal cannulas were used in a Latin square design with 4 dietary treatments, in which crimped barley was replaced with 3 incremental levels of protein supplementation of canola meal. Digesta was collected from the rumen, reticulum, and omasum to represent a 24-h feeding cycle. Nutrient flow was calculated using the reconstitution system based on Cr, Yb, and indigestible neutral detergent fiber and using N-15 as microbial marker. Large and small particles and the fluid phase were recovered from digesta collected at all sampling sites. Bacterial samples were isolated from the digesta collected from the omasum. Several differences existed for digesta composition, nutrient flows, and estimates of ruminal digestibility among the 3 different sampling sites. Sampling site x diet interactions were not significant. The estimated flows of DM, potentially digestible neutral detergent fiber, nonammonia N, and microbial N were significantly different between all sampling sites. However, the difference between DM flow based on sampling from the reticulum and the omasum was small (0.13 kg/d greater in the omasum). The equality between the reticulum and the omasum as sampling sites was supported by the following regression: omasal DM flow = 0.37 (+/- 0.649) + 0.94 (+/- 0.054) reticular DM flow (R-2 = 0.96 and root mean square error = 0.438 kg/d). More deviating nutrient-flow estimates when sampling digesta from the rumen than the reticulum compared with the omasum suggested that sampling from the reticulum is the most promising alternative to the omasal sampling technique. To definitively promote sampling from the reticulum as an alternative to the omasal sampling technique, more research is needed to determine selection criteria of reticular digesta for accurate and precise flow estimates across a range of diets.
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12.
  • Felton, Annika, et al. (författare)
  • The Nutritional Balancing Act of a Large Herbivore: An Experiment with Captive Moose (Alces alces L)
  • 2016
  • Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • The nutrient balancing hypothesis proposes that, when sufficient food is available, the primary goal of animal diet selection is to obtain a nutritionally balanced diet. This hypothesis can be tested using the Geometric Framework for nutrition (GF). The GF enables researchers to study patterns of nutrient intake (e.g. macronutrients; protein, carbohydrates, fat), interactions between the different nutrients, and how an animal resolves the potential conflict between over-eating one or more nutrients and under-eating others during periods of dietary imbalance. Using the moose (Alces alces L.), a model species in the development of herbivore foraging theory, we conducted a feeding experiment guided by the GF, combining continuous observations of six captive moose with analysis of the macronutritional composition of foods. We identified the moose's self-selected macronutrient target by allowing them to compose a diet by mixing two nutritionally complementary pellet types plus limited access to Salix browse. Such periods of free choice were intermixed with periods when they were restricted to one of the two pellet types plus Salix browse. Our observations of food intake by moose given free choice lend support to the nutrient balancing hypothesis, as the moose combined the foods in specific proportions that provided a particular ratio and amount of macronutrients. When restricted to either of two diets comprising a single pellet type, the moose i) maintained a relatively stable intake of non-protein energy while allowing protein intakes to vary with food composition, and ii) increased their intake of the food item that most closely resembled the self-selected macronutrient intake from the free choice periods, namely Salix browse. We place our results in the context of the nutritional strategy of the moose, ruminant physiology and the categorization of food quality.
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13.
  • Gidlund, Helena, et al. (författare)
  • Effects of soybean meal or canola meal on milk production and methane emissions in lactating dairy cows fed grass silage-based diets
  • 2015
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 8093-8106
  • Tidskriftsartikel (refereegranskat)abstract
    • This study evaluated the effects of soybean meal (SBM) and heat-moisture-treated canola meal (TCM) on milk production and methane emissions in dairy cows fed grass silage-based diets. Twenty-eight Swedish Red cows were used in a cyclic change-over experiment with 4 periods of 21 d and with treatments in 2 x 4 factorial arrangement (however, the control diet without supplementary protein was not fed in replicate). The diets were fed ad libitum as a total mixed ration containing 600 g/kg of grass silage and 400 g/kg of concentrates on a dry matter (DM) basis. The concentrate without supplementary protein consisted of crimped barley and premix (312 and 88 g/kg of DM), providing 130 g of dietary crude protein (CP)/kg of DM. The other 6 concentrates were formulated to provide 170, 210, or 250 g of CF/kg of DM by replacing crimped barley with incremental amounts of SBM (50, 100, or 150 g/kg of diet DM) or TCM (70, 140, or 210 g/kg of diet DM). Feed intake was not influenced by dietary CF concentration, but tended to be greater in cows fed TCM diets compared with SBM diets. Milk and milk protein yield increased linearly with dietary CF concentration, with greater responses in cows fed TCM diets compared with SBM diets. Apparent N efficiency (milk N/N intake) decreased linearly with increasing dietary CF concentration and was lower for cows fed SBM diets than cows fed TCM diets. Milk urea concentration increased linearly with increased dietary CP concentration, with greater effects in cows fed SBM diets than in cows fed TCM diets. Plasma concentrations of total AA and essential AA increased with increasing dietary CF concentration, but no differences were observed between the 2 protein sources. Plasma concentrations of Lys, Met, and His were similar for both dietary protein sources. Total methane emissions were not influenced by diet, but emissions per kilogram of DM intake decreased quadratically, with the lowest value observed in cows fed intermediate levels of protein supplementation. Methane emissions per kilogram of energy-corrected milk decreased more when dietary CF concentration increased in TCM diets compared with SBM diets. Overall, replacing SBM with TCM in total mixed rations based on grass silage had beneficial effects on milk production, N efficiency, and methane emissions across a wide range of dietary CP concentrations.
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15.
  • Guinguina, Abdulai, et al. (författare)
  • Postpartum responses of dairy cows supplemented with cereal grain or fibrous by-product concentrate
  • 2021
  • Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 28
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study examined the effect of replacing cereal grain with a fibrous by-product concentrate on nutrient intake, milk production traits and fatty acid composition, diet digestibility, feed conversion efficiency (FCE), CH4 and CO2 emissions, and plasma blood parameters of dairy cows in early lactation. Twenty-two Nordic Red cows were randomly assigned to one of two dietary treatments immediately after calving until 18 weeks in lactation. The cereal grain treatment contained 593 g/kg of grass silage, 317 g/kg of cereal grain mixture (barley, oat, and wheat), 79 g/kg of heat-treated rapeseed meal, and 11 g/kg of a mineral mix on a DM basis. A mixture of unmolassed beet pulp, wheat middlings, barley fibre, and wheat bran replaced cereal grains in the by-product treatment. The diets were isocaloric and isonitrogenous and were fed ad libitum as total mixed rations. The by-product diet had a higher fibre content, while starch content was reduced compared with the cereal grain diet. Despite the 12 %-unit difference in dietary starch content, no differences in DMI were observed. Similarly, no differences in body weight and body condition score (BCS) were observed between treatments. Cows fed the fibrous by-product diet had lower apparent total-tract digestibility of DM (683 g/kg), organic matter (700 g/kg), and crude protein (665 g/kg) compared to those fed cereal grain diet (735, 749, and 699 g/kg, respectively), but milk yield and composition, as well as FCE were not affected by treatment. The edible feed conversion ratio in the by-product group was on average 3.7- folds higher than the cereal grain group. Total CH4 emission (g/d) and CH4 yield (g/kg DMI) reduced by 10.3% on average when by-product replaced cereal grains, but CH4 intensity (g CH4/kg ECM) was not significantly influenced by diet. Although the feeding of by-product had no effect on milk fat content, it changed its fatty acid profile by increasing the proportion of some unsaturated fatty acids (ƩC18:1 trans, C18:3 cis-9 cis-12 cis-15, omega-3) in milk fat. Replacing cereal grain with fibrous by-product in the diets of early lactation dairy cows had no effect on their risk of developing metabolic disorders. These findings suggest that cows fed grass silage-based diets can be supplemented with fibrous by-product concentrates without affecting feed efficiency or energy balance status, thereby supporting sustainable food production. However, future works should evaluate the economic aspects of feeding by-product concentrates to determine their practical application for feed manufacturers and farmers.
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16.
  • Guinguina, Abdulai, et al. (författare)
  • Potential of the Red Macroalga Bonnemaisonia hamifera in Reducing Methane Emissions from Ruminants
  • 2023
  • Ingår i: Animals. - : Multidisciplinary Digital Publishing Institute (MDPI). - 2076-2615. ; 13:18
  • Tidskriftsartikel (refereegranskat)abstract
    • Researchers have been exploring seaweeds to reduce methane (CH4) emissions from livestock. This study aimed to investigate the potential of a red macroalga, B. hamifera, as an alternative to mitigate CH4 emissions. B. hamifera, harvested from the west coast of Sweden, was used in an in vitro experiment using a fully automated gas production system. The experiment was a randomized complete block design consisting of a 48 h incubation that included a control (grass silage) and B. hamifera inclusions at 2.5%, 5.0%, and 7.5% of grass silage OM mixed with buffered rumen fluid. Predicted in vivo CH4 production and total gas production were estimated by applying a set of models to the gas production data and in vitro fermentation characteristics were evaluated. The results demonstrated that the inclusion of B. hamifera reduced (p = 0.01) predicted in vivo CH4 and total gas productions, and total gas production linearly decreased (p = 0.03) with inclusion of B. hamifera. The molar proportion of propionate increased (p = 0.03) while isovalerate decreased (p = 0.04) with inclusion of B. hamifera. Chemical analyses revealed that B. hamifera had moderate concentrations of polyphenols. The iodine content was low, and there was no detectable bromoform, suggesting quality advantages over Asparagopsis taxiformis. Additionally, B. hamifera exhibited antioxidant activity similar to Resveratrol. The findings of this study indicated that B. hamifera harvested from temperate waters of Sweden possesses capacity to mitigate CH4 in vitro.
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17.
  • Hetta, Mårten, et al. (författare)
  • Effects of NaOH-treated wheat and a mixture of barley and oats on the voluntary feed intake and milk production in dairy cows
  • 2013
  • Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 154, s. 103-111
  • Tidskriftsartikel (refereegranskat)abstract
    • An experiment was conducted to examine how including NaOH-treated wheat in the diet of dairy cows affects dry matter intake (DMI) and milk production, using diets based on rolled wheat and an oat/barley mixture for comparative purposes. The study was based on 24 Swedish Red dairy cows that were 147 +/- 51 d in milk (DIM), with an average milk yield of 31 +/- 5.6 kg/d and a live weight of 611 +/- 66 kg. The cows were blocked according to DIM and randomly assigned to six replicated 4 x 4 balanced Latin squares with 21-d experimental periods. The diets were fed as total mixed rations consisting of grass silage supplemented with concentrates in a ratio of 52:48. Four diets were examined: an oat/barley mixture (0BM), 100% rolled wheat (RW) of which 50 (SHW/RW) or 100% was replaced with NaOH treated wheat (SHW). Total tract digestibility was determined using acid-insoluble ash as an internal marker. Ruminal degradation parameters for the cereal feeds were estimated using an in vitro gas production technique and modelling approach. Increased inclusion of Na0H-treated wheat did not affect DMI or milk production. NaOHtreatment reduced (P<0.01) milk protein concentrations and milk N efficiency (P< 0.05),and tended (P=0.10) to decrease milk protein yield. There were no differences between the OBM and RW diets in terms of DMI, milk production, or milk composition. Increased levels of NaOH-treated wheat in the diet caused linear increases (P< 0.05) in faecal N output and estimated urinary volumes and decreasing milk urea concentrations. This indicates that NaOH-treatment increased the mineral load of the diet and shifted starch digestion from the rumen to the small and large intestines. These results were consistent with the lower observed in vitro ruminal digestion rates of NaOH-treated wheat. It is concluded that the oat/barley mixture and the rolled wheat had comparable feeding values despite the higher tabulated metabolisable energy and protein concentrations of the latter. It is concluded that NaOH-treatment of wheat has no beneficial effects that justify its use. (C) 2013 Elsevier B.V. All rights reserved.
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18.
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19.
  • Huhtanen, Pekka, et al. (författare)
  • A meta-analysis of faecal output and nutrient composition, and potential methane emission from manure of dairy cows
  • 2021
  • Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 282
  • Tidskriftsartikel (refereegranskat)abstract
    • A meta-analysis was conducted to predict potential methane emission from manure in dairy cows. Biogas production from manure offers considerable environmental benefits and renewable energy is produced. The developed models predicted faecal concentrations of potentially digestible neutral detergent fibre, neutral detergent solubles and crude protein with adjusted root mean square errors of 15.4, 12.9 and 5.0 g/kg dry matter, respectively. Average model predicted potential methane production (adjusted root mean square error) of 1040 (53.9) g/d per cow, 51.9 (2.5) g/kg dry matter intake and 203 (3.2) g/kg faecal organic matter (volatile solids). Potential methane production from dairy cow manure can be predicted from diet and animal characteristics. Potential methane production is positively related to diet digestibility and daily feed intake. Determination of indigestible neutral detergent fibre concentration by a long ruminal in situ incubation is a useful tool in predictions of potential methane production in dairy cow manure.
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20.
  • Huhtanen, Pekka, et al. (författare)
  • Compartmental flux and in situ methods underestimate total feed nitrogen as judged by the omasal sampling method due to ignoring soluble feed nitrogen flow
  • 2014
  • Ingår i: British Journal of Nutrition. - 0007-1145 .- 1475-2662. ; 111, s. 535-546
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of the present study was to estimate ruminal feed N outflow in lactating cows using the omasal sampling, compartmental flux or in situ method. A total of five ruminally fistulated Finnish Ayrshire dairy cows were used in a 5x5 Latin square study with 21d periods. Experimental silages of grass or red clover harvested at two stages of maturity in addition to a supplement of 90kg concentrate/d were fed to the cows. In vivo omasal N flow was determined using the omasal sampling technique. Ruminal in situ N flow was calculated from N intake and degradability (38m nylon bags). The samples of ruminal contents and faeces were divided into seven particle-size fractions by wet sieving; the concentrations of indigestible neutral-detergent fibre and N were used to calculate N flow in the compartmental flux method. In vivo omasal N flow was greater for the red clover silage diets than for the grass silage diets. The N flow calculated using the compartmental flux technique and that calculated using the in situ technique were highly correlated, but both were less than and poorly correlated with the in vivo N flow. In both in situ and compartmental flux techniques, forage maturity increased the particle-associated N flow, with the increase being significantly greater for the red clover diets than for the grass silage diets. In conclusion, the compartmental flux and in situ methods described the N flow associated with the particle fractions rather than the total ruminal outflow of feed N.
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21.
  • Huhtanen, Pekka, et al. (författare)
  • Evaluation of between-cow variation in milk urea and rumen ammonia nitrogen concentrations and the association with nitrogen utilization and diet digestibility in lactating cows
  • 2015
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 3182-3196
  • Tidskriftsartikel (refereegranskat)abstract
    • Concentrations of milk urea N (MUN) are influenced by dietary crude protein concentration and intake and could therefore be used as a biomarker of the efficiency of N utilization for milk production (milk N/N intake; MNE) in lactating cows. In the present investigation, data from milk-production trials (production data set; n = 1,804 cow/period observations from 21 change-over studies) and metabolic studies involving measurements of nutrient flow at the omasum in lactating cows (flow data set; n = 450 cow/period observations from 29 studies) were used to evaluate the influence of between-cow variation on the relationship of MUN with MNE, urinary N (UN) output, and diet digestibility. All measurements were made on cows fed diets based on grass silage supplemented with a range of protein supplements. Data were analyzed by mixed-model regression analysis with diet within experiment and period within experiment as random effects, allowing the effect of diet and period to be excluded. Between-cow coefficient of variation in MUN concentration and MNE was 0.13 and 0.07 in the production data set and 0.11 and 0.08 in the flow data set, respectively. Based on residual variance, the best model for predicting MNE developed from the production data set was MNE (g/kg) = 238 + 7.0 x milk yield (MY; kg/d) - 0.064 x MY2 - 2.7 x MUN (mg/dL) - 0.10 body weight (kg). For the flow data set, including both MUN and rumen ammonia N concentration with MY in the model accounted for more variation in MNE than when either term was used with MY alone. The best model for predicting UN excretion developed from the production data set (n = 443) was UN (g/d) = -29 + 4.3 x dry matter intake (kg/d) + 4.3 x MUN + 0.14 x body weight. Between-cow variation had a smaller influence on the association of MUN with MNE and UN output than published estimates of these relationships based on treatment means, in which differences in MUN generally arise from variation in dietary crude protein concentration. For the flow data set, between-cow variation in MUN and rumen ammonia N concentrations was positively associated with total-tract organic matter digestibility. In conclusion, evaluation of phenotypic variation in MUN indicated that between-cow variation in MUN had a smaller effect on MNE compared with published responses of MUN to dietary crude protein concentration, suggesting that a closer control over diet composition relative to requirements has greater potential to improve MNE and lower UN on farm than genetic selection.
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22.
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23.
  • Huhtanen, Pekka, et al. (författare)
  • Prediction of rumen fiber pool in cattle from dietary, fecal, and animal variables
  • 2016
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 99, s. 5345-5357
  • Tidskriftsartikel (refereegranskat)abstract
    • Feed intake control in ruminants is based on the integration of physical constraints and metabolic feedbacks. Physical constraints are related to the fill caused by the weight or volume of digesta in the reticulo-rumen. The amount of neutral detergent fiber (NDF) in the rumen (RNDF) may be used as an indicator of rumen till. The objective of this study was to develop equations predicting RNDF from diet and animal characteristics using a meta-analysis technique. A treatment mean data set (n = 314) was obtained from 84 studies, in which rumen pool size and diet digestibility were determined in lactating cows (n = 231) or growing cattle (n = 83). The data were analyzed using linear and nonlinear mixed models. Intake, rumen pool size, and fecal output of NDF were scaled to body weight (BW)(1.0). Due to the heterogeneous nature of dietary NDF, predictions of RNDF based on NDF intake were riot precise. Predictions were markedly improved by dividing NDF into potentially digestible and indigestible fractions, because rumen turnover time of indigestible NDF was 2.7 times longer than that of potentially digestible NDF. At equal NDF intake, RNDF was negatively associated with dietary crude protein concentration and positively with the proportion of concentrate in the diet. Models based on fecal NDF output generally performed better than those based on NDF intake, probably because the effects of intrinsic characteristics of dietary cell walls and associative effects of dietary components collectively influence fecal NDF output. The model based on fecal NDF output was improved by including dietary concentration of forage NDF in the model, reflecting slower turnover of forage NDF compared with concentrate NDF. The curvilinear relationship between fecal NDF output and could be described by a quadratic, Mitscherlich, or power function equation, which performed better than the quadratic or Mitscherlich equation. In addition to fecal NDF output and dietary concentration of forage NDF, animal and forage type had significant effects on RNDF. At the same fecal NDF output, growing cattle had a smaller RNDF than dairy cattle. Increased proportion of alfalfa or corn silages in forage decreased RNDF and increased proportion of tropical forages decreased it. It is concluded that RNDF can be predicted precisely from intake or fecal output data, and that predicted RNDF can be a useful tool in understanding the interplay between physical and metabolic factors regulating feed intake in ruminants.
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24.
  • Huhtanen, Pekka, et al. (författare)
  • Proteinutfodring till mjölkkor
  • 2019
  • Ingår i: Nytt / Sveriges lantbruksuniversitet, Institutionen för norrländsk jordbruksvetenskap.
  • Annan publikation (populärvet., debatt m.m.)
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25.
  • Karlsson, Anna-Karin, et al. (författare)
  • SustAinimal Grazing Living Lab–a survey of grazing management on dairy farms in northern Sweden
  • 2024
  • Ingår i: Acta Agriculturae Scandinavica - Section B. - : Taylor and Francis Ltd.. - 0906-4710 .- 1651-1913. ; 74:1, s. 1-6
  • Tidskriftsartikel (refereegranskat)abstract
    • A survey was conducted on 302 Sweden dairy farms (response rate 98%) to identify grazing and grassland management strategies and main challenges to grazing in northern Sweden. The most common grazing strategy on all dairy farms was continuous grazing (59%) followed by rotational grazing (45%), while organic dairy farms preferentially adopted rotational grazing (69%). The main challenges reported in grazing dairy cows on temporary grasslands on conventional farms were trampling damage and seasonal variations in grass growth, while for organic dairy farmers, the primary challenge was weed control. Only a few farms had grazing on semi-natural grasslands. Future sustainable grazing should focus on optimising grazing strategy in relation to on-farm grazing locations and nutrient supply for high-yielding dairy cows. 
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26.
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27.
  • Krizsan, Sophie Julie, et al. (författare)
  • A meta-analysis of passage rate estimated by rumen evacuation with cattle and evaluation of passage rate prediction models
  • 2010
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 93, s. 5890-5901
  • Tidskriftsartikel (refereegranskat)abstract
    • A meta-analysis of studies using the flux/compartmental pool method with indigestible neutral detergent fiber (iNDF) as internal marker was conducted to study the effect of extrinsic characteristics and forage type on particle passage rate (k(p)) in cattle. Further, the kp prediction equations in the National Research Council (NRC) and the Cornell Net Carbohydrate and Protein System (CNCPS) were evaluated. Data comprised 172 treatment means from 49 studies conducted in Europe and the United States. In total, 145 diets were fed to dairy cows and 27 to growing cattle. A prerequisite for inclusion of an experiment was that dry matter intake, neutral detergent fiber (NDF), proportion of concentrate in the diet, body weight, and diet chemical composition were determined or could be estimated. Mixed model regression analysis including a random study effect was used to generate prediction equations of k(p) and to investigate the relationships between NRC and CNCPS predictions and observed k(p) of iNDF. Prediction equations were evaluated by regressing residual values on the predicted values. The best-fit model when forage type was not included was k(p) (%/h) = 1.19 + 0.0879 x NDF intake (g/kg of body weight) + 0.792 x proportion of concentrate NDF of total NDF + 1.21 x diet iNDF: NDF ratio (adjusted residual mean square error = 0.23%/h). The best general equation accounting for an effect of forage type was as follows: k(p) (%/h) = F + 1.54 + 0.0866 x NDF intake (g/kg of body weight) (adjusted residual mean square error = 0.21%/h), where F is the forage adjustment factor of the intercept. The value of F for grass silage, fresh grass, mixes of alfalfa and corn silage, and dry or ensiled alfalfa as sole forage component were 0.00, -0.91, +0.83, and +0.24, respectively. Relationships between predicted and observed k(p) were y = 0.53(+/- 0.187) + 0.41(+/- 0.0373) x predicted k(p) and y = 0.58(+/- 0.162) + 0.46(+/- 0.0377) x predicted k(p) for the NRC and CNCPS models, respectively. Residual analysis of the NRC and CNCPS models resulted in both significant mean biases (observed-predicted) of -2.40 and -1.70% and linear biases of -0.59 and -0.53, respectively. The results from this meta-analysis suggest that ruminal particulate matter k(p) is affected by forage type in the diet. Further, the evaluation of NRC and CNCPS models showed that passage rate equations developed from marker excretion curves markedly deviated from observed k(p) of iNDF derived using the rumen evacuation technique.
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28.
  • Krizsan, Sophie Julie (författare)
  • Addressing Global Ruminant Agricultural Challenges Through Understanding the Rumen Microbiome: Past, Present, and Future
  • 2018
  • Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 9
  • Forskningsöversikt (refereegranskat)abstract
    • The rumen is a complex ecosystem composed of anaerobic bacteria, protozoa, fungi, methanogenic archaea and phages. These microbes interact closely to breakdown plant material that cannot be digested by humans, whilst providing metabolic energy to the host and, in the case of archaea, producing methane. Consequently, ruminants produce meat and milk, which are rich in high-quality protein, vitamins and minerals, and therefore contribute to food security. As the world population is predicted to reach approximately 9.7 billion by 2050, an increase in ruminant production to satisfy global protein demand is necessary, despite limited land availability, and whilst ensuring environmental impact is minimized. Although challenging, these goals can be met, but depend on our understanding of the rumen microbiome. Attempts to manipulate the rumen microbiome to benefit global agricultural challenges have been ongoing for decades with limited success, mostly due to the lack of a detailed understanding of this microbiome and our limited ability to culture most of these microbes outside the rumen. The potential to manipulate the rumen microbiome and meet global livestock challenges through animal breeding and introduction of dietary interventions during early life have recently emerged as promising new technologies. Our inability to phenotype ruminants in a high-throughput manner has also hampered progress, although the recent increase in "omic" data may allow further development of mathematical models and rumen microbial gene biomarkers as proxies. Advances in computational tools, high-throughput sequencing technologies and cultivation-independent "omics" approaches continue to revolutionize our understanding of the rumen microbiome. This will ultimately provide the knowledge framework needed to solve current and future ruminant livestock challenges.
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29.
  • Krizsan, Sophie Julie, et al. (författare)
  • An in vitro evaluation of browser and grazer fermentation efficiency and microbiota using European moose spring and summer foods
  • 2018
  • Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 8, s. 4183-4196
  • Tidskriftsartikel (refereegranskat)abstract
    • Evolutionary morphological and physiological differences between browsers and grazers contribute to species- specific digestion efficiency of food resources. Rumen microbial community structure of browsers is supposedly adapted to characteristic nutrient composition of the diet source. If this assumption is correct, domesticated ruminants, or grazers, are poor model animals for assessing the nutritional value of food consumed by browsing game species. In this study, typical spring and summer foods of the European moose (Alces alces) were combined with rumen fluid collected from both dairy cows (Bos taurus) and from moose, with the aim of comparing fer- mentation efficiency and microbial community composition. The nutritional value of the food resources was characterized by chemical analysis and advanced in vitro measurements. The study also addressed whether or not feed evaluation based on in vitro techniques with cattle rumen fluid as inoculum could be a practical alternative when evaluating the nutritional value of plants consumed by wild browsers. Our re- sults suggest that the fermentation characteristics of moose spring and summer food are partly host- specific and related to the contribution of the bacterial phyla Firmicutes and Bacteriodetes to the rumen microbial community. Host- specific adaptations of the ruminal microbial community structure could be explained from the evolutionary adaptations related to feeding habitats and morphophysiological differences be- tween browsers and grazers. However, the observed overall differences in microbial community structure could not be related to ruminal digestion parameters measured in vitro. The in vitro evaluation of digestion efficiency reveals that equal amounts of methane were produced across all feed samples regardless of whether the ruminal fluid was from moose or dairy cow. The results of this study suggested that the nutri- tional value of browsers’ spring and summer food can be predicted using rumen fluid from domesticated grazers as inoculum in in vitro assessments of extent of digestion when excluding samples of the white water lily root, but not of fermentation characteristics as indicated by the proportions of individual fermentation fatty acids to the total of volatile fatty acids.
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30.
  • Krizsan, Sophie Julie (författare)
  • Associations among nutrient concentration, silage fermentation products, in vivo organic matter digestibility, rumen fermentation and in vitro methane yield in 78 grass silages
  • 2022
  • Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 285
  • Tidskriftsartikel (refereegranskat)abstract
    • Grass-clover silage constitutes a large part of ruminant diets in Northern and Western Europe, but the impact of silage quality on methane (CH4) production is largely unknown. This study was conducted to identify the quality attributes of grass silage associated with variation in CH4 yield. We expected that silage nutrient concentrations and silage fermentation products would affect CH4 yield, and that these factors could be used to predict the methanogenic potential of the si-lages. Round bales (n = 78) of grass and grass-clover silage from 37 farms in Norway were sampled, incubated, and screened for in vitro CH4 yield, i.e. CH4 production expressed on the basis of incubated organic matter (CH4-OM) and digestible OM (CH4-dOM) using sheep. Concentration of indigestible neutral detergent fiber (iNDF) was quantified using the in situ technique. The data were subjected to correlation and principal component analyses. Stepwise multiple regression was used to model methanogenic potential of silages. Among all investigated silage composition variables, neutral detergent fiber (aNDFom) and water-soluble carbohydrate (WSC) concentra-tions obtained the greatest correlations to CH4-OM (r =-0.63 and r = 0.57, respectively, P < 0.001), while concentration of iNDF negatively correlated with CH4-OM (r =-0.48, P < 0.001). In vivo organic matter digestibility (OMD) and concentration of ammonia-N (NH3-N) in silages were also correlated to CH4-OM (r = 0.44 and r =-0.32, P < 0.001 and P < 0.01, respectively). The stepwise regression using CH4-OM as response variable included aNDFom, WSC, iNDF, silage propionic acid and pH in descending order. The stepwise regression using CH4-dOM as response variable included WSC, aNDFom and iNDF in descending order. Among in vitro rumen short chain fatty acids (SCFA), molar proportion of butyrate was the most prominent in increasing CH4-OM and CH4-dOM (r = 0.23 and r = 0.36, P < 0.05 and P < 0.01, respectively), while molar proportion of propionate was the most prominent SCFA in reducing CH4-OM and CH4-dOM (r =-0.23 and r =-0.26, respectively, P < 0.05). Regression models that account for silage quality attributes can be used to predict CH4 yield from silages with a coefficient of determination (R-2) between 0.33 (CH4-dOM) and 0.65 (CH4-OM). In conclusion, concentration of WSC increased in vitro CH4-OM and CH4-dOM, while concentration of aNDFom and iNDF decreased CH4-OM and CH4-dOM in grass silages.
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31.
  • Krizsan, Sophie Julie, et al. (författare)
  • Behöver vi veta hur mycket korna kan äta?
  • 2013
  • Ingår i: Nytt / Sveriges lantbruksuniversitet, Institutionen för norrländsk jordbruksvetenskap.
  • Annan publikation (populärvet., debatt m.m.)abstract
    • Det finns i Norden flera olika modeller för att skatta konsumtionen hos mjölkkor. I det här projektet ville vi ta reda på vilken modell som fungerar bäst under nordliga förhållanden. Förutsättningarna för vallodling är mycket goda i norra Sverige. Klimatet gynnar produktion av vallfoder med högt energiinnehåll och det är därför viktigt att det bedöms korrekt i foderstaten för högavkastande djur.
  •  
32.
  • Krizsan, Sophie Julie, et al. (författare)
  • Characterization and in vitro assessment of seaweed bioactives with potential to reduce methane production
  • 2022
  • Ingår i: FRONTIERS IN ANIMAL SCIENCE. - : Frontiers Media SA. - 2673-6225. ; 3
  • Tidskriftsartikel (refereegranskat)abstract
    • This study collates compositional analysis of seaweeds data with information generated from in vitro gas production assays in the presence and absence of seaweeds. The aim was to assess and rank 27 native northern European seaweeds as potential feed ingredients for use to reduce methane emissions from ruminants. It provides information for use in future in vivo dietary trials concerning feed manipulation strategies to reduce CH4 emissions efficiently from domestic ruminants based on dietary seaweed supplementation. The seaweeds H. siliquosa and A. nodosum belonging to phylum Phaeophyta displayed the highest concentration of phlorotannins and antioxidant activity among the macroalgae giving anti-methanogenic effect in vitro, while this explanation was not valid for the observed reduction in methane when supplementing with C. filum and L. digitata in this study. D. carnosa and C. tenuicorne belonging to phylum Rhodophyta had the highest protein content among the macroalgae that reduced methane production in vitro. There were no obvious explanation from the compositional analysis conducted in this study to the reduced methane production in vitro when supplementing with U. lactuca belonging to phylum Chlorophyta. The strongest and most complete methane inhibition in vitro was observed when supplementing with Asparagopsis taxiformis that was used as a positive control in this study.
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33.
  • Krizsan, Sophie Julie, et al. (författare)
  • Comparison of in vitro and in situ methods in evaluation of forage digestibility in ruminants
  • 2012
  • Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 90, s. 3162-3173
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this study was to compare the application of different in vitro and in situ methods in empirical and mechanistic predictions of in vivo OM digestibility (OMD) and their associations to near-infrared reflectance spectroscopy spectra for a variety of forages. Apparent in vivo OMD of silages made from alfalfa (n = 2), corn (n = 9), corn stover (n = 2), grass (n = 11), whole crops of wheat and barley (n = 8) and red clover (n = 7), and fresh alfalfa (n = 1), grass hays (n = 5), and wheat straws (n = 5) had previously been determined in sheep. Concentrations of indigestible NDF (iNDF) in all forage samples were determined by a 288-h ruminal in situ incubation. Gas production of isolated forage NDF was measured by in vitro incubations for 72 h. In vitro pepsin-cellulase OM solubility (OMS) of the forages was determined by a 2-step gravimetric digestion method. Samples were also subjected to a 2-step determination of in vitro OMD based on buffered rumen fluid and pepsin. Further, rumen fluid digestible OM was determined from a single 96-h incubation at 38 degrees C. Digestibility of OM from the in situ and the in vitro incubations was calculated according to published empirical equations, which were either forage specific or general (1 equation for all for-ages) within method. Indigestible NDF was also used in a mechanistic model to predict OMD. Predictions of OMD were evaluated by residual analysis using the GLM procedure in SAS. In vitro OMS in a general prediction equation of OMD did not display a significant forage-type effect on the residuals (observed - predicted OMD; P = 0.10). Predictions of OMD within forage types were consistent between iNDF and the 2-step in vitro method based on rumen fluid. Root mean square error of OMD was least (0.032) when the prediction was based on a general forage equation of OMS. However, regenerating a simple regression for iNDF by omitting alfalfa and wheat straw reduced the root mean square error of OMD to 0.025. Indigestible NDF in a general forage equation predicted OMD without any bias (P >= 0.16), and root mean square error of prediction was smallest among all methods when alfalfa and wheat straw samples were excluded. Our study suggests that compared with the in vitro laboratory methods, iNDF used in forage-specific equations will improve overall predictions of forage in vivo OMD. The in vitro and in situ methods performed equally well in calibrations of iNDF or OMD by near-infrared reflectance spectroscopy.
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34.
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35.
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36.
  • Krizsan, Sophie Julie, et al. (författare)
  • Comparison of some aspects of the in situ and in vitro methods in evaluation of neutral detergent fiber digestion
  • 2013
  • Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 91, s. 838-847
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of the present study was to compare digestion rates (k(d)) of NDF for different feeds estimated with the in situ method or derived from an automated gas in vitro system. A meta-analysis was conducted to evaluate how in situ derived k(d) of NDF related to in vivo digestibility of NDF. Furthermore, in vitro true digestibility of the feed samples incubated within filter bags or dispersed in the medium was compared, and k(d) for insoluble and soluble components of those feeds were estimated. Four different concentrates and 4 forages were used in this study. Two lactating Swedish Red cows fed a diet of 60% grass silage and 40% concentrate on DM basis were used for in situ incubations and for collection of rumen fluid. The feed samples were ground through a 2.0-mm screen before the in situ incubations and a 1.0-mm screen before the in vitro gas incubations. In situ nylon bags were introduced into the rumen for determination of k(d) of NDF. Additional kinetic data were produced from isolated NDF and intact samples subjected to in vitro incubations in which gas production was recorded for 72 h. Samples were weighed in the bottles or within filter bags (for fiber and in vitro studies) that were placed in the bottles. The interaction between feed and method was significant (P < 0.01); k(d) of NDF for grass hay tended (P = 0.06) to be less whereas k(d) of NDF for alfalfa, barley grain, canola meal, and dried sugar beet pulp were greater (P < 0.01) when estimated with the in situ method than from gas production recordings. The meta-analysis suggested that in situ derived k(d) of NDF were biased and underestimated in vivo digestibility of NDF. Digestion rates of the intact samples were lower for all feeds, except for the hay, when incubated within the bags compared with dispersed in the medium (P < 0.01). Less OM and NDF were digested for all feeds when incubated within bags than dispersed in the medium (P < 0.01). It is concluded from the in vitro study that microbial activity within the bags is less than in the medium. Significant interactions between method (in situ vs. in vitro) and feed suggest that one or both methods result in biased estimates of digestion kinetics.
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37.
  • Krizsan, Sophie Julie, et al. (författare)
  • Contribution of different segments of the gastrointestinal tract to digestion in growing Saanen goats
  • 2015
  • Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 93, s. 1802-1814
  • Tidskriftsartikel (refereegranskat)abstract
    • This study examined mean retention time (MRT) of particulate and liquid matter in different segments of the gastrointestinal tract (GIT) of growing Saanen goats of different sexes and subjected to different levels of feed restriction. In addition, feeding behavior and total tract digestibility were determined for all animals ahead of slaughter. In total, 54 Saanen goats (18 each of females, castrated males, and intact males) with initial BW 15.3 +/- 0.4 kg were used in a 3 x 3 factorial arrangement comprising the 3 sexes and 3 levels of feed restriction (unrestricted/ad libitum, moderate, and severe restriction). Six blocks per sex group, each consisting of 3 goats, were randomly formed and the goats within each block were randomly allocated to 1 of 3 different feed restrictions. The daily amounts of feed offered to animals subjected to moderate and severe feed restriction (approximately 75% and 50% of ad libitum rate, respectively) were determined within block based on the DMI by ad libitum fed goats on the previous day. The MRT of particulate matter was determined either using Yb-labeled diet or indigestible NDF (iNDF) determined in situ as markers. Mean retention time of the liquid phase was determined by Cr-EDTA. Orthogonal polynomial contrasts were used to determine linear and quadratic effect of feed restriction, while the effect of sex was compared by Tukey test. The effects of sex and the interaction between sex and feed restriction were not significant on most of variables evaluated. Eating, ruminating, and total chewing time per g DM and NDF intake increased linearly as feed restriction increased (P <= 0.03). Diet digestibility increased quadratically for DM and OM, and linearly for NDF as feed intake decreased (P <= 0.03). The MRT of iNDF in the reticulorumen, omasum, abomasum, colon, and total GIT increased linearly with increased feed restriction (P <= 0.01). Mean retention time in the cecum varied quadratically, being greatest for animals with moderate feed restriction. The MRT of liquid was quadratically (P <= 0.04) affected by feed restriction in the reticulorumen, cecum, and total GIT, with the greatest MRT observed for animals subjected to moderate feed restriction. In conclusion, the level of feed restriction increased the MRT of particulate and liquid matter. The MRT was an important mechanism to increase nutrient supply when animals were subjected to feed restriction, as indicated by increased total tract digestibility.
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38.
  • Krizsan, Sophie Julie (författare)
  • Effect of acetic acid, caproic acid and tryptamine on voluntary intake of grass silage by growing cattle
  • 2012
  • Ingår i: Grass and Forage Science. - : Wiley. - 0142-5242 .- 1365-2494. ; 67, s. 361-368
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this study was to identify and quantify fermentation end-products, detected with chromatographic techniques, that were negatively related to intake of grass silage by cattle. Further, the aim was to verify the intake-depressing effect of these compounds in a feeding trial. A set of twenty-four silages that had been used in a previous study to model variations in intake owing to fermentation quality was reanalysed with liquid and gas chromatography. Known and unknown chromatogram peaks were subjected to a regression analysis to determine which were negatively related to intake. Compounds were identified and quantified using a liquid chromatographymass spectrometry system; acetic acid (AcA), caproic acid and tryptamine were chosen for verification. Growing steers were offered wilted silage with these three compounds added, separately or as a mixture, in proportions similar to the maximum values detected in the silages of the previous study. Dietary addition of AcA, either separately or mixed with the other two compounds, reduced silage dry matter (DM) intake. However, the reduction in silage DM intake equalled the amount provided by the added substances, so that no differences in total DM intake were observed for any of the dietary treatments.
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39.
  • Krizsan, Sophie Julie, et al. (författare)
  • Effect of diet composition and incubation time on feed indigestible neutral detergent fiber concentration in dairy cows
  • 2013
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 96, s. 1715-1726
  • Tidskriftsartikel (refereegranskat)abstract
    • Indigestible neutral detergent fiber (NDF) predicts forage digestibility accurately and precisely when determined by a 288-h ruminal in situ incubation, and it is an important parameter in mechanistic rumen models. The long incubation time required is a disadvantage. Further, intrinsic cell wall characteristics of feeds should be determined under ideal conditions for fiber digestion. The objective of this study was to determine the effects of diet composition and rumen incubation time on the concentrations of indigestible NDF (iNDF) for a wide range of feeds in dairy cows. Additionally, predicted concentrations of unavailable NDF generated using the National Research Council (NRC) model and the Cornell Net Carbohydrate and Protein System (CNCPS) were evaluated. Indigestible NDF was evaluated in 18 feeds using 4 cows in a split-split plot design. Treatments were in a 3 x 3 factorial arrangement, consisting of different diets and incubation times. Diet composition was primarily varied by changing the level of concentrate supplementation between 190 (low), 421 (medium), and 625 (high) g/kg of diet dry matter (DM). Grass silage was used as the basal forage for all cows. The feeds were incubated for 144, 216, and 288 h. Indigestible NDF was determined from 2-g samples weighed into polyester bags with a pore size of 12 mu m and a pore area equal to 6% of the total surface area, giving a sample size to surface ratio of 10 mg/cm(2). Across all feeds, the measured iNDF concentrations ranged from 6 to 516 g/kg of DM. The feed iNDF concentration was not affected by the cow used, but diet composition had a significant effect. The mean measured iNDF concentrations for cows consuming low-, medium-, and high-concentrate diets were 178, 186, and 197 g/kg of DM, respectively. The incubation time also affected the feed iNDF concentrations, which averaged 199, 185, and 177 g/kg of DM for 144-, 216-, and 288-h incubations, respectively. We also observed significant interactions between incubation time and feed, and between diet composition and feed, with fiber-rich feeds being most sensitive to these factors. The evaluation of model predictions of unavailable NDF indicated poor precision with prediction errors of 56 (NRC) and 84 (CNCPS) g/kg of DM. Indigestible NDF should be determined based on 288-h ruminal in situ incubations in cows consuming diets with a low proportion of concentrate to represent the feed fraction that is unavailable to the animal.
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40.
  • Krizsan, Sophie Julie, et al. (författare)
  • Effect of dietary supplementation with heat-treated canola meal on ruminal nutrient metabolism in lactating dairy cows
  • 2017
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 100, s. 8004-8017
  • Tidskriftsartikel (refereegranskat)abstract
    • An experiment was conducted to quantify the effects of incremental levels of heat-moisture-treated canola meal (TCM) fed to dairy cows on the relationship between ruminal nutrient digestion and milk production. Experimental diets were fed to 4 multiparous rumencannulated Nordic Red cows, averaging (mean standard deviation) 681 +/- 54.8 kg of body weight, 111 +/- 16 d in milk, and 29.1 +/- 9.1 kg of milk/d at the start of the study, in a Latin square design with four 21-d periods. The 4 experimental dietary treatments consisted of a basal diet of grass silage and crimped barley, and 3 diets in which the crimped barley was replaced with TCM, giving 3 incremental levels of protein supplementation. Nutrient flow was quantified by the omasal sampling technique using 3 markers (Cr, Yb, and indigestible neutral detergent fiber). Continuous infusion of N-15 was used to label bacterial crude protein. Additionally, ruminal sampling and evacuations and measurements of total-tract digestibility were conducted. The experimental diets provided 132, 148, 164, and 180 g of crude protein/kg of dry matter. The increased level of TCM linearly increased dry matter intake from 15.1 to 16.6 kg/d and energy-corrected milk yield from 21.0 to 25.6 kg/d. The increased proportion of TCM when substituting barley with TCM was associated with greater total-tract digestibility of neutral detergent fiber and potentially digestible neutral detergent fiber, which could be explained by increased digestion rate of potentially digestible neutral detergent fiber. Omasal flow of nonammonia N naturally increased with greater dietary TCM inclusion, but the increased intestinal supply of rumen-undegradable protein was partly offset by diminished microbial protein synthesis when feeding more TCM. This was also reflected in a decreased proportion of milk protein from ruminal bacterial protein when TCM supplementation increased.
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41.
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42.
  • Krizsan, Sophie Julie (författare)
  • Effect of grassland cutting frequency, species mixture, wilting and fermentation pattern of grass silages on in vitro methane yield
  • 2023
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • Mitigating enteric methane (CH4) emissions is crucial as ruminants account for 5% of global greenhouse gas emissions. We hypothesised that less frequent harvesting, use of crops with lower WSC concentration, ensiling at low crop dry matter (DM) and extensive lactic acid fermentation would reduce in vitro CH4 production. Timothy (T), timothy + red clover mixture (T + RC) or perennial ryegrass (RG), cut either two or three times per season, was wilted to 22.5% or 37.5% DM and ensiled with or without formic acid-based additive. Silages were analysed for chemical composition and fermentation products. In vitro CH4 production was measured using an automated gas in vitro system. Methane production was, on average, 2.8 mL/g OM lower in the two-cut system than in the three-cut system (P < 0.001), and 1.9 mL/g OM lower in T than in RG (P < 0.001). Silage DM did not affect CH4 production (P = 0.235), but formic acid increased CH4 production by 1.2 mL/g OM compared to the untreated silage (P = 0.003). In conclusion, less frequent harvesting and extensive silage fermentation reduce in vitro CH4 production, while RG in comparison to T resulted in higher production of CH4.
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43.
  • Krizsan, Sophie Julie (författare)
  • Effect of organic grass-clover silage on fiber digestion in dairy cows
  • 2017
  • Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 11, s. 1000-1007
  • Tidskriftsartikel (refereegranskat)abstract
    • There are differences in grass-clover proportions and chemical composition between herbage from primary growth (PG) and regrowth (RG) in grass-clover leys. Mixing silages made from PG and RG may provide a more optimal diet to dairy cows than when fed separately. We tested the hypotheses that increasing dietary proportions of grass-clover silage made from RG compared with PG would increase digestion rate of potentially degradable NDF (pdNDF), and increase ruminal accumulation of indigestible NDF (iNDF). Eight rumen cannulated Norwegian Red cows were used in two replicated 4x4 Latin squares with 21-day periods. Silages were prepared from PG and RG of an organically cultivated ley, where PG and RG silages were fed ad libitum in treatments with RG replacing PG in ratios of 0, 0.33, 0.67 and 1 on dry matter basis in addition to 8 kg concentrate. We evaluated the effect of the four diets with emphasis on rumen- and total tract fiber digestibility. Increasing RG proportions decreased silage intake by 7%. Omasal flow of pdNDF decreased, whereas iNDF flow increased with increasing RG proportions. Increasing RG proportions decreased rumen pool sizes of NDF and pdNDF, whereas pool sizes of iNDF and CP increased. Increasing RG proportions increased digestion rate of NDF, which resulted in greater total tract digestion of NDF. Pure PG diet had the highest calculated energy intake, but the improved rumen digestion of NDF by cows offered 0.33 and 0.67 of RG leveled out milk fat and protein yields among the three PG containing diets.
  •  
44.
  • Krizsan, Sophie Julie (författare)
  • Effect of replacing organic grass-clover silage from primary growth with regrowth on N digestion in dairy cows
  • 2016
  • Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 220, s. 57-66
  • Tidskriftsartikel (refereegranskat)abstract
    • Clover proportions, and thereby chemical composition of herbage, differ between primary growth (PG) and regrowth (RG) in organic managed grass-clover fields. The characteristics of PG and RG silages suggest different supplementary feeding strategies to sustain an efficient milk production in dairy cows. Silage made of the RG generally offers more crude protein (CP) in the diet than silage made of the PG because of an increasing proportion of clover later in the season. Additionally, grass and clover have different amino acid (AA) profiles. His has been suggested to be the first limiting AA in grass silage, while Met has been suggested to be the primarily limiting AA in red clover silage. Eight rumen cannulated Norwegian Red cows were used in two replicated 4 x 4 Latin squares with 21-days periods. Organic PG and RG silages were fed ad libitum in four diets with RG replacing PG silage in ratios of 0, 0.33, 0.67 and 1 on dry matter (DM) basis. Changing RG silage proportions from 0 to 1 increased daily CP intake from 2.90 to 3.08 kg and rumen NH3-concentrations from 4.9 to 8.4 mmol/L, but did not promote a better protein supply. Neither total ruminal outflow of AA nor the AA profile in the small intestine differed between dietary treatments. Met and His were probably the most limiting AA for a higher milk production. Limitations by His may be more related to diets based on PG, while production by cows fed diets based on more RG herbage were more likely limited by Met. (C) 2016 Elsevier B.V. All rights reserved.
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45.
  • Krizsan, Sophie Julie (författare)
  • Effects of alfalfa silage storage structure and roasting corn on ruminal digestion and microbial crude protein synthesis in lactating dairy cows
  • 2012
  • Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 6, s. 624-632
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this experiment was to quantify the effects of unroasted or roasted ground-shelled corn (GSC), when fed with alfalfa ensiled in bag, bunker, or O-2-limiting tower silos on ruminal digestion and microbial CP synthesis in lactating dairy cows. The roasted corn was heat-treated in a propane-fired roasting system. Alfalfa was harvested as second cutting from fields with regrowth of the same maturity. A portion of each field was allotted to each silo. The diets with 3 x 2 factorial arrangement of treatments were fed to six multiparous rumen-cannulated Holstein cows in a cyclic change-over design with five 21-day periods. Experimental diets were comparable and averaged (on dry matter (DM) basis): 410 g/kg alfalfa silage (AS), 150 g/kg corn silage, 350 g/kg GSC, 50 g/kg soybean meal, 40 g/kg roasted soybeans, 177 g/kg CP, 264 g/kg NDF and 250 g/kg starch. Nutrient flow was quantified by the omasal sampling technique with use of three markers (Co, Yb and indigestible NDF). Continuous infusion of 10% atom excess ((NH4)-N-15)(2)SO4 was used to label microbial CP. None of the interactions between storage structure of dietary AS and corn type were significant. DM intake was not different among dietary treatments, averaging 24.5 kg/day across diets. Means of ADF digested in the rumen for cows fed diets with AS from bag, bunker and O-2-limiting tower silo were 2.1, 1.7 and 2.1 kg/day, respectively, and was lower in cows fed AS from the bunker silo. This response may partly be a reflection of the higher intake of ADF by cows fed AS ensiled in the O-2-limiting tower silo compared with the bunker. There was a slightly greater supply of fermentable substrates for cows fed diets with roasted compared with unroasted GSC. The small increases in yield of milk protein and lactose observed in the previous production trial in cows fed diets containing roasted corn may have occurred because of greater supply of fermentable substrates.
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46.
  • Krizsan, Sophie Julie, et al. (författare)
  • Effects on rumen microbiome and milk quality of dairy cows supplemented the macroalga Asparagopsis taxiformis in a grass silage-based diet
  • 2023
  • Ingår i: Frontiers in animal science. - : Frontiers Media SA. - 2673-6225. ; 4
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective was to determine the effects on rumen microbiome and milk quality of reducing the methane (CH4) produced from enteric fermentation by the addition of Asparagopsis taxiformis (AT) to the diets of dairy cows. Six Nordic Red cows at 122 ± 13.7 (mean ± SD) days in milk, of parity 2.7 ± 0.52 and producing 36 kg ± 2.5 kg milk per day at the start of the trial were divided into three blocks by milk yield and assigned to an extra-period Latin-square change-over design comprising two dietary treatments. An extra period of observation was added to the Latin-square change-over design to control for carry-over effects. The dietary treatments were a diet consisting of grass silage and a commercial concentrate mixture (60:40) either not supplemented or supplemented with 0.5% AT on an organic matter intake basis. On average, daily CH4 production, CH4 yield, and CH4 intensity decreased by 60%, 54%, and 58%, respectively, in cows fed the diet supplemented with AT. Furthermore, hydrogen gas emitted by cows fed diets supplemented with AT increased by more than five times compared with cows fed a non-AT-supplemented diet. Feed intake was decreased and milk production altered, reflecting a decreased yield of milk fat in cows fed an AT-supplemented diet, but feed efficiency increased. Rumen fermentation parameters were changed to promote propionate rather than acetate and butyrate fermentation. The most prominent change in milk quality was an increase in bromine and iodine when the diet was supplemented with AT. The reduction in CH4 was associated with a shift from Methanobrevibacter to Methanomethylophilaceae in the archaeal population and a lower relative abundance of Prevotella in the bacterial population. Changes in milk fat odd-numbered and branched-chain fatty acids in the current study of AT supplementation support observed differences in ruminal archaeal and bacterial populations.
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47.
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48.
  • Krizsan, Sophie Julie (författare)
  • Estimation of rumen outflow in dairy cows fed grass silage-based diets by use of reticular sampling as an alternative to sampling from the omasal canal
  • 2010
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 93, s. 1138-1147
  • Tidskriftsartikel (refereegranskat)abstract
    • A study was conducted to compare nutrient flows determined by a reticular sampling technique with those made by sampling digesta from the omasal canal. Six lactating dairy cows fitted with ruminal cannulas were used in a design with a 3 x 2 factorial arrangement of treatments and 4 periods. Treatments were 3 grass silages differing mainly in neutral detergent fiber (NDF) concentrations: 412, 530, or 639 g/kg of dry matter, each combined with 1 of 2 levels of concentrate feed. Digesta was collected from the reticulum and the omasal canal to represent a 24-h feeding cycle. Nutrient flow was calculated using the reconstitution system based on 3 markers (Co, Yb, and indigestible NDF) and using (15)N as a microbial marker. Large and small particles and the fluid phase were recovered from digesta collected at both sampling sites. Bacterial samples from the reticulum and the omasum were separated into liquid-and particle-associated bacteria. Reticular samples were sieved through a 1-mm sieve before isolation of digesta phases and bacteria. Composition of the large particle phase differed mainly in fiber content of the digesta obtained from the 2 sampling sites. Sampling site did not affect marker concentration in any of the phases with which the markers were primarily associated. The 15N enrichment of bacterial samples did not differ between sampling sites. The reticular and omasal canal sampling techniques gave similar estimates of marker concentrations in reconstituted digesta, estimates of ruminal flow, and ruminal digestibility values for dry matter, organic matter, starch, and N. Sampling site x diet interactions were also not significant. Concentration of NDF was 2.2% higher in reconstituted omasal digesta than in reconstituted reticular digesta. Ruminal NDF digestibility was 2.7% higher when estimated by sampling the reticulum than by sampling the omasal canal. The higher estimate of ruminal NDF digestibility with the reticular sampling technique was due to differences in NDF concentration of reconstituted digesta. This study shows that nutrient and microbial protein outflow from the rumen can be measured using a reticular sampling technique. The reticular sampling technique provides a promising alternative to sampling from the omasal canal because there is less interference with the animal and it does not require advanced sampling equipment.
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49.
  • Krizsan, Sophie Julie, et al. (författare)
  • Evaluation of different feed intake models for dairy cows
  • 2014
  • Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 97, s. 2387-2397
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of the current study was to evaluate feed intake prediction models of varying complexity using individual observations of lactating cows subjected to experimental dietary treatments in periodic sequences (i.e., change-over trials). Observed or previous period animal data were combined with the current period feed data in the evaluations of the different feed intake prediction models. This would illustrate the situation and amount of available data when formulating rations for dairy cows in practice and test the robustness of the models when milk yield is used in feed intake predictions. The models to be evaluated in the current study were chosen based on the input data required in the models and the applicability to Nordic conditions. A data set comprising 2,161 total individual observations was constructed from 24 trials conducted at research barns in Denmark, Finland, Norway, and Sweden. Prediction models were evaluated by residual analysis using mixed and simple model regression. Great variation in animal and feed factors was observed in the data set, with ranges in total dry matter intake (DMI) from 10.4 to 30.8 kg/d, forage DMI from 4.1 to 23.0 kg/d, and milk yield from 8.4 to 51.1 kg/d. The mean biases of DMI predictions for the National Research Council, the Cornell Net Carbohydrate and Protein System, the British, Finnish, and Scandinavian models were -1.71, 0.67, 2.80, 0.83, -0.60 kg/d with prediction errors of 2.33, 1.71, 3.19, 1.62, and 2.03 kg/d, respectively, when observed milk yield was used in the predictions. The performance of the models were ranked the same, using either mixed or simple model regression analysis, but generally the random contribution to the prediction error increased with simple rather than mixed model regression analysis. The prediction error of all models was generally greater when using previous period data compared with the observed milk yield. When the average milk yield over all periods was used in the predictions of feed intake, the increase in prediction error of all models was generally less than when compared with previous period animal data combined with current feed data. Milk yield as a model input in intake predictions can be substantially affected by current dietary factors. Milk yield can be used as model input when formulating rations aiming to sustain a given milk yield, but can generate large errors in estimates of future feed intake and milk production if the economically optimal diet deviates from the current diet.
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50.
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