Influence of proportion of wheat in a pasture-based diet on milk yield, methane emissions, methane yield, and ruminal protozoa of dairy cows
| Autor: | B.E. Ribaux, Peter J. Moate, M.S. Islam, Joe L. Jacobs, Murray C. Hannah, G.L. Morris, S.R.O. Williams, William J. Wales, M. H. Deighton, D. Mapleson |
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| Rok vydání: | 2020 |
| Předmět: |
Rumen
Animal feed Biology Poaceae Lolium perenne Pasture 03 medical and health sciences Animal science Lactation Grazing Lolium Genetics medicine Animals Dry matter Herbivory Ciliophora Triticum 030304 developmental biology 0303 health sciences geography geography.geographical_feature_category Australia 0402 animal and dairy science food and beverages 04 agricultural and veterinary sciences biology.organism_classification Animal Feed 040201 dairy & animal science Diet Dairying Milk medicine.anatomical_structure Cattle Female Animal Science and Zoology Methane Food Science |
| Zdroj: | Journal of Dairy Science. 103:2373-2386 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.2019-17514 |
| Popis: | Wheat is the most common concentrate fed to grazing dairy cows in Australia, but no studies have examined the effects of wheat proportion in a pasture-based diet on milk production and methane emissions. In this 47-d experiment, 32 Holstein dairy cows were offered 1 of 4 diets during d 1 to 36. Cows in each of the dietary treatment groups were individually offered no wheat (W0) or wheat at 3 kg of dry matter (DM)/d (W3), 6 kg of DM/d (W6), or 9 kg of DM/d (W9). The remainder of the diet was 2.2 kg of DM of concentrate mix and freshly harvested perennial ryegrass (Lolium perenne) such that all individual cows were offered a total diet of approximately 20.2 kg of DM/d. From d 37 to 47 the diets of cows receiving treatments W0 and W3 remained unchanged, but cows in treatments W6 and W9 received the W3 diet. Individual cow feed intakes, milk yields, milk compositions, and methane emissions were measured for d 31 to 35 (period 1) and d 45 to 47 (period 2). During period 1, the mean intakes of cows offered the W0, W3, W6, and W9 diets were 19.2, 20.4, 20.2, and 19.8 kg of DM/d. Diet caused differences in energy-corrected milk, and means for W0, W3, W6, and W9 were 29.5, 32.4, 33.0, and 32.9 kg/d, respectively. Milk fat percentage differed with respective means of 3.93, 3.94, 3.69, and 3.17. Diets also caused differences in methane emissions, with means for W0, W3, W6, and W9 of 440, 431, 414, and 319 g/d. During period 1, the cows fed the W9 diet produced less methane and had lower methane yields (g/kg of DMI) and intensities (g/kg of energy-corrected milk) than cows fed the W3 diet. However, in period 2 when the wheat intake of cows in the W9 treatment was reduced to the same level as in the W3 treatment, their methane emissions, yields, and intensities were similar to those offered the W3 treatment, yet protozoa numbers in ruminal fluid were still much lower than those in cows offered the W3 treatment. Our research shows that for diets based on perennial ryegrass and crushed wheat, only the diet containing more than 30% crushed wheat resulted in substantially depressed milk fat concentration and reduced methane emissions, methane yield, and methane intensity. Thus, although feeding a diet with a high proportion of wheat can cause substantial methane mitigation, it can come at the cost of depression in milk fat concentration. |
| Databáze: | OpenAIRE |
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