| 1. |
|
|
| 2. |
- Bernes, Gun, et al.
(författare)
-
Forskning pågår - från foder till ost
- 2018
-
Ingår i: Nytt / Sveriges lantbruksuniversitet, Institutionen för norrländsk jordbruksvetenskap.
-
Annan publikation (populärvet., debatt m.m.)abstract
- I ett samarbete mellan Norrmejerier, Växa Sverige och institutioner vid SLU i Umeå och i Uppsala pågår tre sammanlänkade projekt där vi studerar hur ostens kvalitet påverkas av olika faktorer, från gård till mejeri. De bakterier och andra mikroorganismer som finns i foder, mjölk och ost studeras särskilt noga. Vi vill bland annat veta vad mikrofloran har för inverkan på ostens lagringstid och på dess smak och konsistens.
|
|
| 3. |
- Bernes, Gun, et al.
(författare)
-
Från vallfoder till ost
- 2019
-
Ingår i: Svenska vallbrev. - 1653-8064. ; , s. 3-5
-
Tidskriftsartikel (populärvet., debatt m.m.)
|
|
| 4. |
- Bernes, Gun, et al.
(författare)
-
Vad påverkar mikrofloran i mjölken på gård och mejeri?
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- När man producerar långtidslagrad ost är det viktigt att kunna förutsäga lagringstiden och minimera förlusterna i produktionen från ystning till lagring och leverans av färdigt produkt. Mejeriet kan styra över processer och lagring men kan bara i begränsad omfattning påverka mjölkråvarans sammansättning. Projektet har syftat till att undersöka sambandet mellan olika gårdsfaktorer och sammansättning och mikroflora i mjölkråvaran på gården (gårdsmjölken). Dessutom undersöktes sambandet mellan mjölkråvaran på mejeriet (silomjölken) och kvaliteten och mognadstiden hos långtidslagrade ostar. Vi ville också studera säsongsvariationen hos mjölkråvarans kvalitet med fokus på mikrofloran. Studien inleddes med att dokumentera produktionen av mjölk på gårdar som levererar mjölk till mejeriet i Burträsk och dessutom några ekologiska gårdar som jämförelse. Totalt omfattande studien 43 gårdar. Dokumentationen inleddes med en enkät rörande gårdarnas storlek, inhysning, vallproduktion, fodermedel, mjölkningsrutiner mm. Enkätsvaren har kompletterats med data från Växa Sverige (Kokontrollen). Gårdarna har besökts vid två tillfällen då grovfoderprover tagits som analyserats för fermentationskvalitet. För att studera säsongsvariationen i mjölkråvarans kvalitet under ett år har prov från gårdarnas mjölktankar samlats in månadsvis av tankbilschaufförerna (utöver ordinarie provtagning). Proverna har analyserats för traditionella parametrar, inklusive totalantal bakterier och termoresistenta bakterier, men även för aktiviteten av plasmin, ett enzym som bryter ned mjölkens protein. För att få information om vilka bakterier som förekommer i gårds- och silomjölk, dvs sammansättningen av mjölkens mikroflora, har prover analyserats med molekylär teknik, s.k. DNA-sekvensering. Resultaten beskriver bakteriernas fördelning i procent men anger inte hur många de är i absoluta tal eller vilken betydelse de har. För att studera sambanden mellan gårdsdata, mjölkkvalitet inklusive mikroflorans sammansättning, och säsong har vi skapat ett antal matriser som länkar olika typer av information till varandra och bearbetat data med multivariata statistiska metoder. Vi har utifrån detta försökt utvärdera vilka faktorer på gården som påverkar gårdsmjölkens kvalitet, mikroflora och plasminaktivitet. Den viktigaste faktorn för totalantal bakterier och mikroflorans sammansättning visade sig vara vilket mjölkningssystem som fanns på gården, dvs bås, grop eller robot. Gårdar med robotmjölkning hade högre antal bakterier och fler termoresistenta bakterier i mjölken jämfört med de andra systemen. De hade även en annan sammansättning av mikrofloran jämfört med gårdar med mjölkning på bås. Mjölkning i grop visade sig vara ett mellanting mellan bås- och robotsystem när det gäller bakterier. Vi kunde även se att mjölknings- och diskrutiner hade betydelse för mikroflorans sammansättning och mjölkkvalitet, liksom hygienen på båspallen, användning av gummimatta och att korna inte klövverkas för sällan. I projektets andra del studerades kopplingen mellan silomjölkens sammansättning och produktion och lagring av långtidslagrad ost. Vi tog prover från mjölksilos innan pastörisering av mjölken och analyserade dessa för samma parametrar som för gårdsmjölken i den första delen av projekt, inklusive DNA-analyser av mikrofloran. Vid mejeriet i Burträsk tillverkas ost i stor skala och varje mjölksilo innehåller mjölk från ett stort antal gårdar. Mjölken som provtogs och analyserades i den här delen av studien kom i huvudsak från de gårdar som ingick i projektet men även från ett antal gårdar som inte deltog i projektet. Silomjölken provtogs från februari 2016 till februari 2017. Vid varje tillfälle togs prov från två eller tre silos. Ostar som producerades av mjölken provtogs och analyserades på alla traditionella parametrar inklusive sensoriska analyser. Detta gjordes efter 14 månaders mognadstid och därefter fram till att de bedömts som färdiga. För att förstå sambanden mellan silomjölk och ostproduktion analyserades data med multivariata statistiska metoder. Det fanns endast svaga samband mellan silomjölkens mikroflora före pastörisering och den resulterande ostens kvalitet och lagringstid. Det fanns dock viss koppling mellan mjölkens kvalitet och utbytet av ystningen, dvs hur mycket mjölk 4 som går åt för att göra ett kilo ostmassa; förhöjda värden för celltal, fria fettsyror, totalantal bakterier och pH var kopplat till minskat utbyte, medan högre fett- och proteinhalt var kopplat till ett högre utbyte. Orsaken till att vi bara ser svaga samband mellan silomjölkens sammansättning inklusive mikroflora, och ostens kvalitet, beror främst på att silomjölken är en blandning av mjölk från många gårdar, vilket gör att vi inte ser den tydliga variation som finns mellan enskilda gårdar.
|
|
| 5. |
- Eliasson, Thomas, et al.
(författare)
-
Epiphytic microbiota in Swedish grass-clover herbage and the effect of silage additives on fermentation profiles and bacterial community compositions of the resulting silages
- 2023
-
Ingår i: Journal of Applied Microbiology. - 1364-5072 .- 1365-2672. ; 134
-
Tidskriftsartikel (refereegranskat)abstract
- Aims To investigate the epiphytic microbiota in grass-clover herbage harvested at different sites and occasions and to explore the effect of different silage additives on the resulting silage microbiota.Methods and results Herbage was harvested from grass-clover leys at geographically distributed sites in a long-term field experiment in Sweden, in early and late season of two consecutive years. Different silages were made from the herbage using: (1) no additive, (2) acid-treatment, and (3) inoculation by starter culture. Herbages were analysed for botanical and chemical composition, and the resulting silages for products of fermentation. Bacterial DNA was extracted from herbage and silage samples, followed by sequencing using Illumina 16S rRNA amplicon sequencing. Herbage microbiota showed no clear correlation to site or harvesting time. Silage additives had a major effect on the ensiling process; inoculation resulted in well fermented silages comprising a homogenous microbiota dominated by the genera Lactobacillus and Pediococcus. A minor effect of harvest time was also observed, with generally a more diverse microbiota in second-harvest silages. Untreated silages showed a higher relative abundance (RA) from non-lactic acid bacteria compared to acid-treated silages. In most silages, only a few bacterial amplicon sequence variants contributed to most of the RA.Conclusions The epiphytic microbiota in grass-clover herbage were found to be random and not dependent on site. From a microbial point of view, the most predictable and preferable silage outcome was obtained by inoculation with a starter culture. Acid-treatment with formic- and propionic acid surprisingly resulted in a less preferable silage. Silage making without additives cannot be recommended based on our results.
|
|
| 6. |
- 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.
|
|
| 7. |
- Gidlund, Helena, et al.
(författare)
-
Milk production and methane emissions from dairy cows fed a low or high proportion of red clover silage and an incremental level of rapeseed expeller
- 2017
-
Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 197, s. 73-81
-
Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the effects of including increasing levels of rapeseed expeller in dairy cow diets with a low or high proportion of red clover silage on milk production and methane emissions. A total of 32 lactating Swedish Red dairy cows were used in a cyclic change-over design with three periods of 21 days, in a 2x4 factorial arrangement of treatments. The total mixed ration consisted of 600 g/kg dry matter (DM) of forage and 400 g/kg DM of concentrate on a DM basis. The forage treatments consisted of a 30:70 or 70:30 ratio of grass to red clover silage (RC30 and RC70). A basal supplement consisted of crimped barley and premix, formulated to contain 130 g CP/kg DM. For the three additional concentrate supplements, crimped barley was gradually replaced with incremental levels of rapeseed expeller to reach 170, 210 or 250 g CP/kg DM. No differences in feed intake were found between RC30 and RC70, but a positive response was found to increased dietary CP concentration from rapeseed expeller. Increasing proportion of red clover silage did not have any effect on production, while increasing dietary CP concentration increased yield of milk, energy corrected milk (ECM) and milk protein. Nitrogen efficiency was higher with diet RC30 than with RC70 and decreased with increasing dietary CP concentration, while milk urea nitrogen increased. Methane (CH4) emissions per unit feed intake decreased with dietary CP concentration and tended to increase with increasing proportion of red clover silage in the diet. Increased CP intake from red clover silage in the diet of dairy cows had no positive effect on CH4 emissions.
|
|
| 8. |
|
|
| 9. |
- Gustavsson, Anne-Maj, et al.
(författare)
-
Effects of morphological fractions on estimated milk yields in forage maize depending on growing site and plant maturity
- 2013
-
Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 63, s. 131-142
-
Tidskriftsartikel (refereegranskat)abstract
- This study was undertaken to determine the effects of the morphological fractions of forage maize for milk production as predicted by the spread sheet model called MILK 2006. The plants were harvested at increasing maturities at three different sites in Sweden and separated into stems, leaves, kernels and cobs. Chemical and in vitro analyses of the plant fractions as specified in the MILK 2006 model for predicting estimated milk yields Milk Mg-1 dry matter (DM) and Milk ha(-1) were undertaken. Partial least squares regression analysis was used to evaluate the impact of the proportions and qualities of the fractions on Milk Mg-1 DM and Milk ha(-1). Estimated milk yields could not be predicted based on the proportions of the fractions and their nutritional values. The most important parameters for determining Milk ha(-1) was the DM yield, and for the estimated Milk Mg-1 were the concentrations of starch and the fibre digestibility of the whole crop.
|
|
| 10. |
- Hetta, Mårten, et al.
(författare)
-
Effects of hybrid and maturity on performance and nutritive characteristics of forage maize at high latitudes, estimated using the gas production technique
- 2012
-
Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 171, s. 20-30
-
Tidskriftsartikel (refereegranskat)abstract
- We evaluated effects of hybrid and advancing plant maturity on performance, chemical composition, and nutritional characteristics of whole plant forage maize as well as the relative contributions of its plant fractions at high latitudes. Three maize hybrids, Avenir (FAO 180), Isberi (FAO 190) and Burli (FAO 210), were grown in southern Sweden in a field experiment with a replicated complete randomized block design. Plants were harvested four times during maturation, and dry matter (DM) yield and DM as a proportion of fresh weight were recorded. Whole plants were separated into four morphological fractions representing stems, leaves, kernels and cobs and the contribution of each fraction to the DM of the whole plant was estimated. Plant material was subjected to chemical analysis followed by measurement of in vitro gas production (GP) in buffered rumen fluid and finally, by calculation of in vitro true digestibility of organic matter (OM) and neutral detergent fibre (aNDFom). The GP profiles were fitted to a first order kinetic model with a discrete lag. Parameters describing the GP profiles were used in a recently developed mechanistic two compartment rumen degradation model to estimate in vivo OM digestibility (OMD) and first order rate of degradation in the rumen. Hybrids were compared and effects of maturity were assessed by analysis of variance using DM concentration as covariate. There were differences (P<0.05) among the hybrids in DM yield and relative contributions of the plant fractions. Differences (P<0.05) in modelled in vivo digestibility of OM and rates of degradation also occurred among hybrids. Increased maturity caused a reduction in in vitro digestibility of aNDFom in all plant fractions (P<0.05), but increased the rate of rumen degradation of OM in the whole plant as evaluated from GP results. The DM yield had a quadratic relationship with increasing maturity, with maximum yield at a DM concentration of about 370 g/kg. In vitro GP can describe the nutritive characteristics of forage maize in relation to advancing maturity and increased maturity affected agronomic performance and plant composition as well as the nutritive characteristics of hybrids. (C) 2011 Elsevier B.V. All rights reserved.
|
|
| 11. |
- 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.
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
- Hetta, Mårten, et al.
(författare)
-
Prediction of nutritive values, morphology and agronomic characteristics in forage maize using two applications of NIRS spectrometry
- 2017
-
Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 67, s. 326-333
-
Tidskriftsartikel (refereegranskat)abstract
- This study evaluates nutritive, morphological and agronomic characteristics of forage maize predicted by using a high-quality near-infrared (NIR) spectrometer and an NIR hyperspectralimaging technique using partial least squares (PLS) regression models. The study includes 132 samples of dried milled whole-plant homogenates of forage maize with variation in maturity, representing two growing seasons, three locations in Sweden and three commercial maize hybrids. The samples were measured by a classical sample cup NIR spectrometer and by a pushbroom hyperspectral-imaging instrument. The spectra and a number of variables (crude protein, CP, neutral detergent fibre, starch, water soluble carbohydrates (WSC) and organic matter digestibility), morphological variables (leaves, stems & ears) and crop yield were used to make PLS calibration models. Using PLS modelling allowed the determination of how well maize variables can be predicted from NIR spectra and a comparison of the two types of instruments. Most examined variables could be determined equally well, by both instruments, but the pushbroom technique gave slightly better predictions and had higher analytical capacity. Predictions of CP, starch, WSC and the proportions of ears in the maize gave robust. The findings open new possibilities to further utilise the technology in plant breeding, crop management, modelling and forage evaluation.
|
|
| 18. |
- Hetta, Mårten, et al.
(författare)
-
Responses in dairy cows to increased inclusion of wheat in maize and grass silage based diets
- 2010
-
Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 60, s. 219-229
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of including wheat in the total mixed rations of dairy cows were evaluated using a 4??4 Latin square dose response experiment with 28 dairy cows (Swedish red). The animals were averaging 150 days in milk at the start of the experiment. Diets consisted of mixtures of maize and grass silage with wheat grain at four levels (8, 16, 24 and 32% of dry matter (DM)). The animals consumed 17.8, 19.7, 21.1 and 23.8 kg of DM and produced 28.1, 29.1 29.6 and 30.2 kg of energy corrected milk, respectively. Digestibility of DM and neutral detergent fibre (NDF) was determined using indigestible NDF (iNDF) as a marker. DM digestibility, feed intake and milk and protein yields increased with increasing wheat content while the milk fat concentration, the digestibility of NDF and the feed efficiency of the diets decreased
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
- Huhtanen, Pekka, et al.
(författare)
-
Comparison feed intake and milk production responses in continuous and change-over design dairy cow experiments
- 2012
-
Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 143, s. 184-194
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to compare feed intake and milk production responses in continuous and change-over design dairy cow experiments with a meta-analysis. The dataset included 988 treatment means (354 in continuous and 632 in change-over trials) from 204 studies. Sub-datasets from studies investigating the effects of the amount (n=217) and crude protein (CP) concentration of concentrate (n=336 diets) were analyzed separately. Mixed model regression analysis with a random study effect was used evaluate the effects of experimental design on feed intake and milk production responses. Concentrate dry matter (DM) intake, dietary CP or metabolizable protein, total DM intake index and metabolizable energy intake were used as independent variables in univariate models. In addition, multiple regression models were developed from the continuous and change-over trial data and cross-validated using the other data. Generally the intake and milk production responses did not depend on experimental design, and the P-values for the interactions between the experimental design and independent variables were high. When the data from studies displaying large variation in the intake potential were analyzed separately, change-over designs tended to underestimate milk production responses. However, up to the range of 5kg/day in DM intake potential within a study the feed intake and milk production responses to the changes in nutrient supply were similar irrespective experimental designs. The analysis of five cyclic-change-over studies including 60 diets indicated that there was no relationship between the direct and carry-over effects of dietary treatments. The mean squares of carry-over effects were on average similar to the error mean squares. The probability of the significance of carry-over effects was not different from the random effects. It is concluded that the change-over designs are as accurate as continuous designs in estimating feed intake and milk production responses, excluding studies with extreme treatments resulting in extensive mobilization of body fat and protein.
|
|
| 22. |
- Huhtanen, Pekka, et al.
(författare)
-
Evaluation of canola meal as a protein supplement for dairy cows: A review and a meta-analysis
- 2011
-
Ingår i: Canadian Journal of Animal Science. - 0008-3984. ; 91, s. 529-543
-
Tidskriftsartikel (refereegranskat)abstract
- Huhtanen, P., Hetta, M. and Swensson, C. 2011. Evaluation of canola meal as a protein supplement for dairy cows: A review and a meta-analysis. Can. J. Anim. Sci. 91: 529-543. A review and a meta-analysis were conducted to compare the feeding value of soybean meal (SBM) and canola meal (CM) in dairy cows and to evaluate the effects of heat-treatment of CM (TCM) on the performance of dairy cows. The dataset included in total 292 treatment means from 122 studies, in which dietary crude protein (CP) concentration was increased by replacing energy supplements with protein supplements. A mixed model regression analysis with random study effect was used to estimate the marginal production responses to different protein sources. The differences between the slopes were compared by t-test. All protein sources increased dry matter intake, but the responses were greater (P<0.01) for CM and TCM compared with SBM. Feeding CM or TCM produced greater (P<0.01) daily milk yield responses than SBM (3.4 +/- 0.19 and 3.7 +/- 0.25 vs. 2.1 +/- 0.25) kg kg(-1) in CP intake. Marginal milk protein yield responses (g kg(-1) increase in CP intake) were greater (P <0.01) for CM (136 +/- 5.4) and TCM (133 +/- 8.5) compared with SBM (98 +/- 8.0). Smaller response to incremental CP intake can partly be related to the higher average dietary CP concentration in SBM studies. Literature data on rumen ammonia N concentration and omasal protein flow did not support the higher ruminal tabulated ruminal CP degradability of CM compared with SBM. It is concluded that CM can successfully be substituted for SBM on isonitrogenous basis and that most feed evaluation systems overestimate metabolizable protein concentration of SBM relative to CM.
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Karlsson, Linda, et al.
(författare)
-
New methodology for estimating rumen protein degradation using the in vitro gas technique
- 2009
-
Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 153, s. 193-202
-
Tidskriftsartikel (refereegranskat)abstract
- This paper explores the possibility of estimating in vitro degradable crude protein (IVDP) and effective crude protein (CP) degradation (EPD) of protein feeds in the rumen using a new method based on the in vitro gas production (GP) technique of Raab et al. [Raab, L., Cafantaris, B., Jilg, T., Menke, K.H., 1983. Romeo protein degradation and biosynthesis. 1. A new method for determination of protein degradation in rumen fluid in vitro. Br. J. Nutr. 50, 569-582]. Cold-pressed hempseed cake, cold-pressed rapeseed cake, rapeseed expeller, heat-treated rapeseed meal and soybean meal, used as test feeds, were incubated with buffered rumen fluid and carbohydrates at four concentrations, and amounts of ammonia-N and gas produced were measured after 4,8,12,16,24, and 30 h. The new GP technique included a number of methodological changes. Samples for ammonia-N analysis were collected from the same flask at every sampling time, and rumen fluid was pre-incubated with carbohydrates to enhance microbial activity and reduce background ammonia-N levels. Results using the new methodology showed that feed, time and feed x time interaction all affected IVDP estimates (P<0.01). Estimated EPD values obtained using the GP method were affected by feed (P<0.001), and were 0.33, 0.36, 0.46. 0.59 and 0.67 for hempseed cake, rapeseed meal, rapeseed expeller, rapeseed cake and soybean meal, respectively. We conclude that the new GP technique, compared to the original method, can provide more practical estimates of IVDP that enable calculations of EPD values of protein feeds. Additional studies are required to further validate the reliability of the method using feeds with known in vivo responses in order to develop the technique into a useful method for estimating CP degradation in the rumen. (C) 2009 Elsevier B.V. All rights reserved.
|
|
| 28. |
- 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.
|
|
| 29. |
- Krizsan, Sophie Julie, et al.
(författare)
-
Evaluation of the feed intake models in the Nordic feed evaluation system NorFor
- 2014
-
Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 64, s. 110-122
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate the feed intake models in the Nordic feed evaluation system NorFor. Data from 196 feeding experiments with dairy cows, and 17 experiments of periodical data, and 135 experiments of complete data with growing cattle were used in the evaluation by mixed model regression. The feed intake by both dairy cows and growing cattle were overestimated by the models. A linear bias indicated that over prediction increased with level of intake both by dairy cows and growing cattle. Most animal and diet factors were significantly related to the residuals, which indicated that those factors did not act independently in the predictions of feed intake. This kind of errors can restrict future ration formulation and animal performance, since animal production parameters included in the prediction models will be a consequence of the diet fed at the time they were measured.
|
|
| 30. |
- Krizsan, Sophie Julie, et al.
(författare)
-
Gas production kinetics in predictions of voluntary intake of grass silage by cattle
- 2012
-
Ingår i: Journal of Animal and Feed Sciences. - : The Kielanowski Institute of Animal Physiology and Nutrition, PAS. - 1230-1388. ; 21, s. 234-250
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to predict voluntary intake by cattle of grass silages of different fermentation quality from in vitro gas production data. Further, biological concepts of intake related gas data were examined by cluster analysis to silage chemical composition. Samples from 24 grass silages were characterized from their gas profiles. Observed silage dry matter intake was modelled by partial least squares regression analysis. Cumulative gas volumes and rates of gas production during early incubation, asymptotic gas volume as well as discrete lag time, and cumulative gas volumes at 48 and 72 h were the best descriptors of the variation in silage intake. The discrete lag time had a strong negative influence on intake and made up clusters with chemical variables indicating secondary fermentation. In vitro gas production data did not improve silage dry matter intake predictions compared with current models based on chemical analysis of silage fermentation quality.
|
|
| 31. |
- Krizsan, Sophie Julie, et al.
(författare)
-
Predicting feeding value of forage maize hybrids harvested at different maturities and sites
- 2014
-
Ingår i: Journal of Animal and Feed Sciences. - : The Kielanowski Institute of Animal Physiology and Nutrition, PAS. - 1230-1388. ; 23, s. 269-278
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate two near-infrared reflectance spectroscopy (NIRS) applications and different laboratory methods for determining indigestible neutral detergent fibre (iNDF) and organic matter digestibility (OMD) of forage maize hybrids harvested at high latitudes. Different in situ and in vitro methods have been used in calibrations of NIRS for routine determinations of forage feed value in the Nordic countries. Swedish and Finnish NIRS calibrations of iNDF generated biased estimates of low precision of iNDF determined in situ. All methods used to predict OMD in forage maize systematically underestimated the observed OMD calculated from the in situ determined value of iNDF. Digestibility was determined with least precision based on the enzymatic in vitro procedure. Values of OMD based on the in vitro incubation in buffered rumen fluid displayed the smallest error among the laboratory methods. The NIRS calibration developed with the forage maize samples of this study, suggested that NIRS has a great potential to predict iNDF and OMD of forage maize accurately and precisely. It was concluded that NIRS predictions of OMD can be a promising tool for evaluating performance of forage maize hybrids at high latitudes if NIRS calibrations of iNDF including forage maize samples are available.
|
|
| 32. |
- Lardy, Quentin, et al.
(författare)
-
Effects of daytime or night-time grazing on animal performance, diurnal behaviour and enteric methane emissions from dairy cows at high latitudes
- 2024
-
Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - 0906-4702 .- 1651-1972. ; 73, s. 28-42
-
Tidskriftsartikel (refereegranskat)abstract
- This study compared animal performance and enteric methane (CH4) emissions from dairy cows in a part-time grazing (PTG) system in northern Sweden. Twenty-four Nordic Red dairy cows were allocated to one of two treatments: DAY (10 h daytime pasture access) or NIGHT (12 h night-time pasture access). The cows in each treatment received the same ad libitum partial mixed ration (PMR) indoors and ad libitum herbage allowance. Methane was recorded using two linked GreenFeedTM emissions monitoring (GEM) units, on pasture and indoors. Day or night grazing showed no statistical differences in estimated grass or PMR intake, milk production or daily enteric CH4 emissions. There was a rapid decrease in diurnal CH4 emissions (28%) when the cows were moved from indoors to pasture in both grazing treatments. Using two GEM units (indoor, outdoor) in combination improved the diurnal assessment of enteric CH4 emissions during PTG conditions in the mixed feeding system.
|
|
| 33. |
- Lorenz, Martin, et al.
(författare)
-
Recycling of microbial N and estimation of protein degradation by in vitro gas production
- 2011
-
Ingår i: Animal Feed Science and Technology. - : Elsevier BV. - 0377-8401 .- 1873-2216. ; 170, s. 111-116
-
Tidskriftsartikel (refereegranskat)abstract
- Rumen fluid (RF) activity has great impact on in vitro incubation measurements for feed evaluation in ruminant nutrition. When feed protein degradability is estimated from the release of ammonia (NH(3)), the presence of protozoa in RF and their release of NH(3) from phagocytosis of rumen bacteria may influence degradation estimates. The objective of this study was to improve the in vitro gas production (GP) method, as applied to protein degradation measurements, by defaunation of RF. Soybean meal was incubated as a protein source along with graded levels of carbohydrates and buffered RF, which was either defaunated by centrifugation or untreated. Gas production and NH(3) were recorded continuously during 23 h. Extrapolation of these recordings to zero GP was used as a theoretical value for NH(3) release from feed protein degradation at zero microbial growth. Results showed that defaunation reduced NH(3) concentration in blank incubations, which was particularly evident at longer incubation intervals compared to untreated RF. This effect was likely caused by eliminating bacterial N recycled by protozoa. Defamation lowered NH(3) release in the soybean meal incubations by 55% (P<0.002) and also the estimates of in vitro degradation of crude protein (IVDP) at different incubation times, while GP was only reduced by 13% (P<0.008). However, incubations with defaunated RF resulted in depleted NH(3) concentrations in early stages of incubation, which led to unreliable estimates of IVDP for these intervals. Further improvements of the method should therefore consider an adequate addition of NH(3) at the start of the incubation. These improvements are important to eventually establish the methods as an alternative to other protein evaluation methods. (C) 2011 Elsevier B.V. All rights reserved.
|
|
| 34. |
|
|
| 35. |
- Morel, Julien, et al.
(författare)
-
Challenges for Simulating Growth and Phenology of Silage Maize in a Nordic Climate with APSIM
- 2020
-
Ingår i: Agronomy. - : MDPI AG. - 2073-4395. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- APSIM Next Generation was used to simulate the phenological development and biomass production of silage maize for high latitudes (i.e., >55 degrees). Weather and soil data were carefully specified, as they are important drivers of the development and growth of the crop. Phenology related parameters were calibrated using a factorial experiment of simulations and the minimization of the root mean square error of observed and predicted phenological scaling. Results showed that the model performed well in simulating the phenology of the maize, but largely underestimated the production of biomass. Several factors could explain the discrepancy between observations and predictions of above-ground dry matter yield, such as the current formalization of APSIM for simulating the amount of radiation absorbed by the crop at high latitudes, as the amount of diffuse light and intercepted light increases with latitude. Another factor that can affect the accuracy of the predicted biomass is the increased duration of the day length observed at high latitudes. Indeed, APSIM does not yet formalize the effects of extreme day length on the balance between photorespiration and photosynthesis on the final balance of biomass production. More field measurements are required to better understand the drivers of the underestimation of biomass production, with a particular focus on the light interception efficiency and the radiation use efficiency.
|
|
| 36. |
- Mussadiq, Zohaib, et al.
(författare)
-
Plant development, agronomic performance and nutritive value of forage maize depending on hybrid and marginal site conditions at high latitudes
- 2012
-
Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 62, s. 420-430
-
Tidskriftsartikel (refereegranskat)abstract
- The objectives of this investigation were to study the effects of marginal site conditions and hybrid on plant development, agronomic performance and nutritive characteristics of forage maize (Zea mays L.) at high latitudes. Field experiments were conducted in 2008 and 2009 at three experimental sites, Kristianstad, Skara and Vasteras, at increasing latitudes from 55 degrees-60 degrees N. Experimental design used two replicated randomized complete blocks at each site with three maize hybrids, Avenir (FAO 180), Isberi (FAO 190) and Burli (FAO 210), which were continuously assessed for plant development and harvested at various levels of maturity. The chemical composition and nutritional characteristics of harvested plant materials were analysed and hybrid responses to advancing maturity in terms of yield and nutritional qualities were evaluated. Results showed that maize hybrids required different numbers of accumulated thermal units at sites on varying latitudes to achieve developmental stages. Lowest thermal unit requirements among hybrids were observed for hybrid Avenir, and for sites it was highest for plants grown in the most northern site, Vasteras. The most southern site, Kristianstad, was the only site at which all hybrids reached the dent stage (c. 450 g kg(-1) kernel DM), a recommended maturity for ensiling. The DM yields of early maturing hybrid Avenir were consistently lower than those for Isberi and Burli at all the sites. Results also revealed nutritional differences among maize hybrids at a given maturity (DM, g kg(-1)), indicating that the effects of maturation should be factored into design of hybrid performance trials. This study highlights the effects of marginal site conditions and hybrids on plant development, agronomic performance and nutritional characteristics of maize hybrids at high latitudes. Further studies on marginal sites are recommended to enlighten the understanding of interaction between environmental and genetic factors on the performance of forage maize.
|
|
| 37. |
- Nkurunziza, Libére, et al.
(författare)
-
Crop genotype-environment modelling to evaluate forage maize cultivars under climate variability
- 2014
-
Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 64, s. 56-70
-
Tidskriftsartikel (refereegranskat)abstract
- A crop model and environmental data were used to simulate genotype-environment interactions for commercial forage maize cultivars. Genotype parameters defined by the MAISPROQ model were calibrated to observed aboveground dry matter (DM) yield and quality (concentrations of DM and starch) data from Swedish field experiments 2009-2011 on four forage maize cultivars with different maturation rates (Avenir, Isberi, Jasmic and Burli). The model calibration predictability (coefficient of determination, R-2) ranged from 0.18 to 0.45 for yield and 0.40 to 0.86 for quality. The corresponding values for validation were in a similar range for the growth model but less for the quality model (0.36-0.38 and 0.25-0.54, respectively). Thereafter the model was used to assess the cultivar performance for different locations and future climate conditions. The simulated DM yield averaged for 2003-2009 varied between 5% and 25% among nine locations in Sweden due to differences in weather conditions, depending on cultivar. The proportion of years with successful harvest (34% DM concentration being achieved by 31 October) varied between 60% and 100% for the early cultivar (Avenir) and 0% and 70% for the late cultivar (Jasmic). Under future climate conditions, harvest of the early-maturing cultivar (Avenir) will occur earlier (by up to 19 days in Lund [55.6 degrees N] and 24 days in Uppsala [59.8 degrees N] by 2085), but with unchanged or even slightly decreased DM yields compared with current levels. The starch concentration will remain almost unchanged in Lund but increase in Uppsala, especially for the late-maturing cultivar. We regard the model predictions of quality to be reasonably satisfactory, whereas those of DM yields are less reliable due to observations for calibration being available only for the period after flowering. Therefore, more frequent sampling in the early growing season is required to improve the predictive power of the model, especially for DM yield.
|
|
| 38. |
|
|
| 39. |
- Priyashantha, Hasitha, et al.
(författare)
-
Composition and Properties Has Little Impact on Cheese Ripening: Insights from a Traditional Swedish Long-Ripening Cheese
- 2021
-
Ingår i: Dairy. - : MDPI AG. - 2624-862X. ; 2, s. 336-355
-
Tidskriftsartikel (refereegranskat)abstract
- The monthly variation in raw dairy silo milk was investigated and related to the ripening time of the resulting cheese during an industrial cheese-making trial. Milk composition varied with month, fat and protein content being lowest in August (4.19 and 3.44 g/100 g, respectively). Casein micelle size was largest (192–200 nm) in December–February and smallest (80 nm) in August. In addition, SCC, total bacteria count, proteolytic activities, gel strength, and milk fatty acid composition were significantly varied with month. Overall sensory and texture scores of resulting cheese were mainly influenced by plasmin and plasminogen activity, indicating the importance of native proteolytic systems. Recently, concepts based on the differentiated use of milk in dairy products have been suggested. For the investigated cheese type, there might be little to gain from such an approach. The variation in the investigated quality characteristics of the dairy milk used for cheese making had little effect on cheese ripening in our study. In contrast to our hypothesis, we conclude that as long as the quality of the milk meets certain minimum criteria, there are only weak associations between cheese milk characteristics and the time required for the development of aroma and texture in the cheese. To find answers behind the observed variation in cheese ripening time, studies on the effects of process parameters are needed.
|
|
| 40. |
- Priyashantha, Hasitha, et al.
(författare)
-
Composition and properties of bovine milk: A study from dairy farms in northern Sweden; Part I. Effect of dairy farming system
- 2021
-
Ingår i: Journal of Dairy Science. - : Elsevier. - 0022-0302 .- 1525-3198. ; 104:8, s. 8582-8594
-
Tidskriftsartikel (refereegranskat)abstract
- This study was part of a larger project that aimed to understand the causes for increasing variation in cheese ripening in a cheese-producing region in northern Sweden. The influence of different on-farm factors on raw milk composition and properties was investigated and is described in this paper, whereas the monthly variation in the milk quality traits during 1 yr is described in our companion paper. The dairy farming systems on a total of 42 dairy farms were characterized through a questionnaire and farm visits. Milk from farm tanks was sampled monthly over 1 yr and analyzed for quality attributes important for cheese making. On applying principal component analyses to evaluate the variation in on-farm factors, different types of farms were distinguished. Farms with loose housing and automatic milking system (AMS) or milking parlor had a higher number of lactating cows, and predominantly Swedish Holstein (SH) breed. Farms associated with tiestalls had a lower number of lactating cows and breeds other than SH. Applying principal component analyses to study the variation in composition and properties of tank milk samples from farms revealed a tendency for the formation of 2 clusters: milk from farms with AMS or a milking parlor, and milk from farms with tiestall milking. The interaction between the milking system, housing system, and breed probably contributed to this grouping. Other factors that were used in the characterization of the farming systems only showed a minor influence on raw milk quality. Despite the interaction, milk from tiestall farms with various cow breeds had higher concentrations (g/100 g of milk) of fat (4.74) and protein (3.63), and lower lactose concentrations (4.67) than milk from farms with predominantly SH cows and AMS (4.32, 3.47, and 4.74 g/100 g of milk, respectively) or a milking parlor (4.47, 3.54, and 4.79 g/100 g of milk, respectively). Higher somatic cell count (195 × 103/mL) and lower free fatty acid concentration (0.75 mmol/100 g of fat) were observed in milk from farms with AMS than in milk from tiestall systems (150 × 103/mL and 0.83 mmol/100 g of fat, respectively). Type of farm influenced milk gel strength, with milk from farms with predominantly SH cows showing the lowest gel strength (65.0 Pa), but not a longer rennet coagulation time. Effects of dairy farming system (e.g., dominant breed, milking system, housing, and herd size) on milk quality attributes indicate a need for further studies to evaluate the in-depth effects of farm-related factors on milk quality attributes.
|
|
| 41. |
- Priyashantha, Hasitha, et al.
(författare)
-
Composition and properties of bovine milk: A study from dairy farms in northern Sweden; Part II. Effect of monthly variation
- 2021
-
Ingår i: Journal of Dairy Science. - : Elsevier. - 0022-0302 .- 1525-3198. ; 104:8, s. 8595-8609
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the influence of monthly variation on the composition and properties of raw farm milk collected as part of a full-scale cheese-making trial in a region in northern Sweden. In our companion paper, the contribution of on-farm factors to the variation in milk quality attributes is described. In total, 42 dairy farms were recruited for the study, and farm milk samples were collected monthly over 1 yr and characterized for quality attributes of importance for cheese making. Principal component analysis suggested that milk samples collected during the outdoor period (June–September) were different from milk samples collected during the indoor period. Despite the interaction with the milking system, the results showed that fat and protein concentrations were lower in milk collected during May through August, and lactose concentration was higher in milk collected during April through July than for the other months. Concentrations of free fatty acids were generally low, with the highest value (0.86 mmol/100 g of fat) observed in February and the lowest (0.70 mmol/100 g of fat) observed in June. Plasmin and plasminogen-derived activities varied with sampling month without a clear seasonal pattern. The pH of farm tank milk ranged from 6.60 to 6.82, with the lowest and highest values in September and February, respectively. The highest somatic cell count was observed in August (201 × 103 cells/mL) and the lowest in April (143 × 103 cells/mL). The highest value of gel strength, was recorded in December (88 Pa) and the lowest in July (64 Pa). Rennet coagulation time and gel strength were inversely correlated, with the lowest rennet coagulation time value observed in December. Orthogonal projections to latent structures (OPLS) and discriminant analysis adaptation of OPLS identified casein micelle size and total proteolysis as the milk quality attributes with major responses to sampling month, with smaller casein micelle size and higher total proteolysis associated with the outdoor months. Using discriminant analysis adaptation of OPLS to further investigate causes behind the variation in milk traits revealed that there were factors in addition to feeding on pasture that differed between outdoor and indoor months. Because fresh grass was seldom the primary feed in the region during the outdoor period, grazing was not considered the sole reason for the observed difference between outdoor and indoor periods in raw milk quality attributes.
|
|
| 42. |
- Priyashantha, Hasitha, et al.
(författare)
-
Computed tomography (CT) scanning to visualize eye formation and internal structure in Grevé cheese
- 2024
-
Ingår i: Heliyon. - : Elsevier Ltd. - 2405-8440. ; 10:13
-
Tidskriftsartikel (refereegranskat)abstract
- The size and distribution of the eyes play a crucial role for the sensory attributes, aesthetic value and quality of the cheese. This article focuses on investigating the feasibility of using computed tomography (CT) scanning as a non-destructive tool to observe early-stage eye formation in Grevé cheese within an industrial trial. It is crucial to achieve a perfect combination of small and big sized eyes, evenly distributed within the cheese wheel, without having cracks/splits for optimal quality. Such variations could be visualized using CT-scanning of cheeses at a young and mature stage by providing high-resolution, three-dimensional CT-scanning images of the cheese's internal structure, without the need for physical dissection. Further, the distribution of eyes, their shape and number, could be visualized and compared for the same cheese scanned at young and mature stages. Thus, the importance of monitoring eye formation through non-destructive techniques is emphasized to ensure consistent product quality.
|
|
| 43. |
- Priyashantha, Hasitha, et al.
(författare)
-
Determining the end-date of long-ripening cheese maturation using NIR hyperspectral image modelling: A feasibility study
- 2021
-
Ingår i: Food Control. - : Elsevier BV. - 0956-7135 .- 1873-7129. ; 130
-
Tidskriftsartikel (refereegranskat)abstract
- Near-infrared (874–1734 nm) hyperspectral (NIR-HS) imaging, coupled with chemometric tools, was used to explore the relationship between spectroscopic data and cheese maturation. A predictive tool to determine the end-date of cheese maturation (E-index, in days) was developed using a set of 425 NIR-HS images acquired during industrial-scale cheese production. The NIR-HS images were obtained by scanning the cheeses at 14, 16, 18 and 20 months of ripening, before a final sensorial assessment in which all cheeses were approved by 20 months. Regression modelling by partial least squares (PLS) was used to explore the relationship between average spectra and E-index. The best PLS model achieved 69.6% accuracy in the prediction of E-index when standard normal variate (SNV) correction and mean centring pre-processing were applied. Thus, NIR-HS image modelling can be useful as a complementary tool to optimise the logistics/efficiency of cheese ripening facilities by rapid and non-destructive prediction of the end-date of ripening for individual cheeses. However, the commercial application will require future improvements in the predictive capacity of the model, e.g. for larger datasets and repetitive scans of cheeses on random occasions.
|
|
| 44. |
- Priyashantha, Hasitha, et al.
(författare)
-
Impact of farm type and sampling month on the composition and properties of bovine milk in northern Sweden
- 2021
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Dairy farms in Northern Sweden were characterized to investigate the effect of on-farm factors and season on the variation in milk quality. Based on principal component analyses (PCA), two major types of dairy farming systems were observed. Type-1: Larger farms with loose housing using automatic milking system or milking parlour with predominantly Swedish Holstein (SH) breed. Type-2: Farms with a lower number of cows in tie-stalls with breeds other than SH. PCA of variation in composition and properties of the milk samples showed a tendency for the formation of two clusters based on these farming systems. The interrelated effect of the milking system and breed is likely to contribute to this distribution. Type of farm influenced the gel strength, probably reflecting differences in milk composition. Total proteolysis and casein micelle size were mainly influenced by sampling month, with smaller micelles and slightly higher proteolysis in outdoor compared to the indoor period. Season associated differences in raw milk are not merely linked to the variation in the amoun
|
|
| 45. |
- Priyashantha, Hasitha, et al.
(författare)
-
Interactive effects of casein micelle size and calcium and citrate content on rennet-induced coagulation in bovine milk
- 2019
-
Ingår i: Journal of Texture Studies. - : Wiley. - 0022-4901 .- 1745-4603. ; 50, s. 508-519
-
Tidskriftsartikel (refereegranskat)abstract
- Interactive effects of casein micelle size and milk calcium and citrate content on rennet-induced coagulation were investigated. Milk samples containing small (SM) and large (LM) micelles, obtained from individual Holstein cows, were modified by addition of calcium and/or citrate and milk coagulation properties were evaluated in a full factorial design. The results showed that LM milk had a higher relative proportion of casein, coagulated faster, and resulted in a stronger gel than SM milk. Addition of calcium slightly decreased casein micelle size, while addition of citrate slightly increased micelle size. Calcium addition resulted in a shorter coagulation time and the strongest gels, while citrate addition increased the coagulation time and resulted in the weakest gels. Addition of calcium and citrate in combination resulted in intermediate coagulation properties. The interactive effect of micelle size and citrate was significant for gel strength. Microstructural differences between the milk gels were consistent with the rheological properties, for example, the micrographs revealed that a more homogeneous network was formed when calcium was added, resulting in a stronger gel. A more inhomogeneous network structure was formed when citrate was added, resulting in a weaker gel. Thus, variations in casein micelle size and in calcium and citrate content influence rennet-induced coagulation in bovine milk. The calcium and citrate contents in Swedish milk have changed over time, whereby calcium content has increased and citrate content has decreased. In practical cheese making, calcium is added to cheese milk, most likely altering the role of inherent citrate and possibly influencing casein micelle size. The observed interaction effect between casein micelle size and citrate in this study, suggests that larger micelles with moderate citrate level will result in firmer gels, whereas a higher citrate content reduced gel strength more in case of large than SM. Since firmer gels are likely to retain more protein and fat than less firmer gels, this interaction effect could have implications in practical cheese production.
|
|
| 46. |
|
|
| 47. |
- Priyashantha, Hasitha, et al.
(författare)
-
Use of near-infrared hyperspectral (NIR-HS) imaging to visualize and model the maturity of long-ripening hard cheeses
- 2020
-
Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774. ; 264
-
Tidskriftsartikel (refereegranskat)abstract
- Spectroscopic measurements and imaging have great potential in rapid prediction of cheese maturity, replacing existing subjective evaluation techniques. In this study, 209 long-ripening hard cheeses were evaluated using a hyperspectral camera and also sensory evaluated by a tasting panel. A total of 425 NIR hyperspectral (NIR-HS) images were obtained during ripening at 14, 16, 18, and 20 months, until final sensorial approval of the cheese. The spectral data were interpreted as possible compositional changes between scanning occasions. Regression modelling by partial least squares (PLS) was used to explain the relationship between average spectra and cheese maturity. The PLS model was evaluated with whole cheeses (average spectrum), but also pixelwise, producing prediction images. Analysis of the images showed an increasing homogeneity of the cheese over the time of storage and ripening. It also suggested that maturation begins at the center and spreads to the outer periphery of the cheese.
|
|
| 48. |
|
|
| 49. |
|
|
| 50. |
|
|
