Effect of two dietary crude protein levels on energy balance and milk production in dairy cows during early postparturient period
2004
Areerath Akatvipat(Chiang Mai University, Chiang Mai (Thailand). Faculty of Veterinary Medicine) | Suvichai Rojanasthien(Chiang Mai University, Chiang Mai (Thailand). Faculty of Veterinary Medicine) | Theera Rukkwamsuk(Kasetsart University. Kamphaeng Saen Campus, Nakhon Pathom (Thailand). Faculty of Veterinary Medicine. Dept. of Medicine)
Objective was to study the effect of two dietary crude protein levels in concentrates on energy balance and milk production in dairy cows during early post parturient period. Twenty two dry cows were randomly allocated into 2 groups, 11 cows (Group A) were fed a concentrate consisted of 20 percent Crude protein and 11 cows (Group B) were fed a concentrate consisted of 18 percent crude protein. Blood samples were collected weekly beginning at 1 week before expected calving until 12 week after calving to determine blood biochemical parameters. Milk yield was recorded daily, and milk samples were collected weekly to determine their compositions of fat, protein, and lactose. Results showed that milk production of cows in Group A tended to be higher than in Group B (17.90+-2.97 vs 16.32+-2.21 kg/day). The composition of milk did not differ, except, the percentage of protein for group A were higher than for Group B (3.17+-0.09 vs 2.95+-0.10 g/100 g of milk). The result indicated that the energy balance after calving was negative for both groups, particularly during the first 5 weeks of lactation. The mean serum concentrations of non-esterified fatty acid (NEFA) and B-hydroxybutyrate (BHB) of Group B were higher than Group A at the second week of lactation (0.84+-0.27 vs 0.52+-0.26 mEq/L and 0.72+-0.27 vs 0.67+-0.18 mmol/L for NEFA and BHB, respectively). Our results suggested that the concentrate consisted of 20 percent crude protein was more appropriate to use in high producing dairy cows at the early stage of lactation than 18 percent crude protein concentrate.
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