| Abstrakt: |
Sixty-three multiparous Alpine does were blocked by pregnancy type (single vs. multiple) on d 90 of pregnancy and assigned to one of nine diets to evaluate the interaction of prepartum protein and energy intake on BW change, kidding, and subsequent production and composition of milk. Treatments were factorial with three percentages of CP (8.5, 11.5, and 14.5% of DM) and three concentrations of metabolizable energy (1.80, 2.16, and 2.53 Mcal/kg of DM). Does were fed for ad libitum intake during pregnancy and switched to a lactation diet (16% CP and 2.35 Mcal of metabolizable energy/kg of DM) after parturition. Milk production and composition were recorded for the first 15 wk of lactation. Prepartum BW gain increased quadratically as protein amount increased but was unaffected by energy. Kidding rate, litter weight, and gestation length were unaffected by protein or energy amounts. Milk production in the subsequent lactation increased quadratically in response to prepartum CP (2.59, 3.26, and 3.07 kg/d for 8.5, 11.5, and 14.5% CP, respectively). Milk production increased linearly in response to prepartum metabolizable energy concentration (2.63, 3.05, and 3.26 kg/d for 1.80, 2.16, and 2.53 Mcal/kg of DM, respectively). Milk fat percentage increased linearly in response to increased prepartum energy. Production of milk fat, protein, SNF, FCM, and SCM were affected quadratically by increased prepartum CP and linearly by prepartum energy, following the pattern for milk production. The present recommendations for prepartum CP and energy appear to be adequate for gestation and subsequent lactation performance of dairy goats. |
