• • • Pregastric digestion and milk productivity of cows as affected by various concentration of structural carbohydrates
Experiment took place on two groups of Holstein black-and-white cows, having annual milk productivity of 8000 kg. Increase in concentration of structural carbohydrates from 32.8 to 34.5% in dry matter (DM) in the period of DIM (days in milk) by additional feeding with gramineous hay had no effect on DM consumption, compared to the control. Analyses of metabolite concentration in ruminal fluid revealed decrease in microbial mass by 26.5% (Р ≤ 0.05) as well as amylolytic activity and amount of volatile fatty acids, indicating the reduced hydrolysis of carbohydrates. Cow diet, containing 34.5% of neutral detergent fiber (NDF) in DM led to decline in total yield of whole milk by 7.2% (Р ≤ 0.05) for 120 days of lactation, compared to the control, and milk protein yield — by 7.8% (Р ≤ 0.05), increasing forage costs by 5.4%. It was calculated that increase in ratio of rough feed by 3.4% reduced costs for fodder, used in the experiment, as well as total costs for milk production by 5.1%. However, that had no effect on additional profit from milk sale.
Source: http://kormoproizvodstvo.ru/en/8-2018-2/, p. 35
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