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- Elgemark, Emma, et al.
(författare)
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Effect of mechanical processing of ley crop silages on in vitro gas production and neural digestive fibre digestion
- 2020
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Ingår i: Grassland Science in Europe. ; , s. 632-634
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Konferensbidrag (refereegranskat)abstract
- Reducing silage particle size can increase forage intake through enhanced rumen passage rate. Increased passage rate might depress rumen digestion and counteract the positive effect of intake on nutrient supply. Extrusion is a mechanical treatment causing particle size reduction and plant cells to break open, resulting in improved fermentation in biogas reactors. The objective of this study was to investigate if extrusion could increase in vitro ruminal digestion of silage. Primary growth of timothy and red clover silage, harvested at two maturity stages, was processed in an extruder. In vitro incubations with rumen liquid were performed over 72 h in a system with continuous measurement of gas production. Analysis of neutral detergent fibre (NDF) digestion was performed on fermented residues. Extrusion increased gas production from both timothy and clover, indicating improved digestion, and enhanced NDF degradation of late harvest timothy and early harvest red clover silage. Extrusion has the potential to increase rumen digestion of ley crop silage.
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- Elgemark, Emma, et al.
(författare)
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Intensiv mekanisk bearbetning av ensilage – ett sätt att öka smältbarheten?
- 2020
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Ingår i: Report from the Department of Crop Production Ecology (VPE). - 1653-5375. ; , s. 63-66
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Grovfoder är det naturliga foderslaget för nötkreatur. Grovfoderkonsumtionen begränsas av grovfoderfoderpartiklarnas relativt långa uppehållstid i vommen och därför behövs betydande mängder kraftfoder för att tillgodose mjölkkornas näringsbehov. Minskad storlek hos grovfoderpartiklarna kan ge ökat grovfoderintag genom att foderpartiklarna passerar snabbare genom vommen. Ökad passagehastighet kan emellertid sänka fodersmältbarheten och därmed motverka den positiva effekt på näringsförsörjningen som ökad konsumtion innebär. Extrudering av foder är en processmetod där mekanisk bearbetning av fodret medför minskad partikelstorlek och uppluckring av cellstrukturen i växtmaterial som är rika på lignocellulosa. Metoden har gett förbättrat utbyte i biogasreaktorer vilket indikerar att den även skulle kunna ha positiv effekt på grovfodrets smältbarhet i kon. Syftet med denna studie var att undersöka om extrudering ökar in vitro-smältbarheten av gräs- respektive klöverensilage. Ensilage från förstaskörd av timotej respektive rödklöver, vid två olika utvecklingsstadier, bearbetades i en s.k. bioextruder. Prover av ensilagen inkuberades med vomvätska under 72 timmar i ett in vitro-system med kontinuerlig mätning av gasproduktion. Extrudering ökade den totala gasproduktionen och fermentationshastigheten från både timotej och klöver, vilket indikerar förbättrad vomsmältbarhet. Resultaten antyder att extrudering har potential att öka utnyttjandet av vallensilage och andra typer av grovfoder utfodrade till idisslare.
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- Emanuelson, Ulf, et al.
(författare)
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Feasibility of EVolutionary OPeration (EVOP) as a concept for herd-specific management in commercial dairy herds
- 2020
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 235
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Tidskriftsartikel (refereegranskat)abstract
- Dairy farming is a complex production system involving biological, technological and human inputs. Therefore, `general knowledge of cause and effect' often seems inadequate to identify and implement optimal management procedures. To solve herd-specific problems, this paper explores the potential of planned experiments for internal use at the farm level to take advantage of local causal relationships. The shift towards larger dairy herds with access to automatic data recordings of a large number of relevant inputs and performance indicators supports the development of management tools that are able to estimate the effect of changes made in daily management on individual farms. The concept of EVolutionary OPeration (EVOP) implies making small systematic changes in production factors or procedures while running the production and continuously evaluating the results. The aim of this study was to develop and evaluate the feasibility of implementing EVOP in commercial dairy herds as an integral part of herd management. The concept of EVOP-Dairy is based on five principles: (1) farmer-driven identification of areas for improvement; (2) herd-specific goals for the interventions to be evaluated in EVOP trials; (3) a short EVOP trial period; (4) simple, but statistically sound, EVOP designs including data access and (5) regular estimation of intervention effects and frequent reporting to the farmer. The project involved three activities: first, visiting a number of dairy farms with the aim of identifying areas for management improvements and to define potential EVOP interventions and relevant designs of EVOP trials; second, conducting a series of EVOP trials to develop data registration, statistical models, analysis and reporting; third, interviewing the farmers to obtain their opinion of the conceptual idea and the process. These activities were documented for the twelve project farms, and five different EVOP trials are described in detail to illustrate the concept. In conclusion, the farmers found the concept a useful management improvement tool, although the EVOP trials created additional work. The EVOP-Dairy statistical models need to include dynamic multilevel data and control for confounding factors when estimating intervention effects, as design with randomization was not feasible in the majority of the identified EVOP trials. Therefore, future development for the EVOP-Dairy should focus on (i) easy to implement and execute interventions, (ii) guidelines to interpret intervention effect when practical conditions hinder fully randomized and well replicated interventions, and (iii) automation of the data analysis and reporting part of the concept.
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- Eriksson, Torsten, et al.
(författare)
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Effects on milk urea concentration, urine output, and drinking water intake from incremental doses of potassium bicarbonate fed to mid-lactation dairy cows
- 2014
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 97, s. 4471-4484
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Tidskriftsartikel (refereegranskat)abstract
- Large variation exists in the potassium content of dairy cow feeds and also within a feed type due to soil type and fertilization. Increased ration K concentration causes a subsequent increase in urinary volume and could be expected to also lower milk urea concentration. Six multiparous mid-lactation Swedish Red dairy cows, all fitted with rumen cannulas, were subjected to 3 different levels of K intake in a Latin square experiment with three 2-wk periods to evaluate the effects on concentrations of milk urea and rumen ammonia, urinary output, and drinking water intake. The treatments were achieved by K supplementation on top of a low-K basal ration fed at individual allowances fixed throughout the experiment. The basal ration, consumed at 20.2 kg of dry matter (DM)/d, provided 165 g of crude protein/kg of DM and consisted of grass silage, concentrates, and urea in the proportions 39.3:60.0:0.7 on a DM basis. Potassium bicarbonate supplementation was 0, 616, and 1,142 g/d, respectively, to give total ration K concentrations that were low (LO; 12 g/kg of DM), medium (MED; 23 g/kg of DM), or high (HI; 32 g/kg of DM). Production and composition of milk was not affected by treatment. A linear effect on milk urea concentration was detected, being 4.48, 4.18, and 3.77 mM for LO, MED, and HI, respectively, and a linear tendency for rumen ammonia concentration with 6.65, 6.51, and 5.84 mg of NH3-N/dL for LO, MED, and HI, respectively. Milk urea concentration peaked about 3 h after the rumen ammonia peak from the morning feeding, at a level 1.3 mM over the baseline. Urinary urea excretion declined linearly (105, 103, and 98 g of urea-N/d for LO, MED, and HI, respectively). Linear increases occurred in urinary output (0.058 +/- 0.001 kg of urine/g of K intake; no intercept; coefficient of determination = 0.997) and drinking water intake (65.9 +/- 2.02 0.069 +/- 0.004 kg of water/g of K intake; coefficient of determination = 0.95). Urinary K concentration leveled off at 12.4 g/L. Urinary creatinine excretion was not affected by K addition, but allantoin excretion increased linearly by 27% from LO to HI, suggesting increased rumen microbial growth. Rumen pH, acetate proportion of total volatile fatty acids, and digestibility of DM, organic matter, and neutral detergent fiber increased linearly with increasing potassium intake. We concluded that increased ration K concentration lowers milk urea concentration with a magnitude significant for the interpretation of milk urea values, but other sources of variation, such as sampling time relative to feeding, may be even more important.
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| 10. |
- Eriksson, Torsten, et al.
(författare)
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Finns det mervärden med biokol i nötgårdens foderkedja? Resultat från ensilering och utfodring
- 2023
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Ingår i: Report from the Department of Crop Production Ecology (VPE). - 1653-5375. ; , s. 188-191
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- I ett projekt finansierat av SLU Ekoforsk studeras effekten på olika ställen i foderkretsloppet vid tillförsel av biokol på en gård med nötkreatur. Biokol tillförs i fodret vid ensilering eller på annat sätt. Resultat finns nu beträffande effekter på ensilagekvalitet och på äldre kvigor vid utfodring. Ensilagekvaliteten var god med undantag för en timotejgröda med låg halt av torrsubstans (ts), där en redan hög smörsyrahalt ökade linjärt vid en stegvis ökad tillsats av 0–6 % biokol på ts-basis. Andelen lösligt råprotein i rödklöver minskade marginellt vid ökad biokoltillsats. Äldre kvigor konsumerade 11,2–11,8 kg ts ensilage/dag från blandvall, utan någon signifikant skillnad om biokoltillsatsen var 0, 1,5 eller 3 % på ts-basis. Det var inte heller någon signifikant skillnad vad gäller ts-smältbarhet. Med ökad tillsats av biokol ökade träck-ts och träckkonsistensen blev fastare. Effekten var större om biokol blandades in i det färdiga ensilaget strax före utfodring än om det tillsattes vid ensileringen.
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