Effects of prepartum dietary protein level and feed intake on postpartum lactation performance and feeding behavior of multiparous Holstein dairy cows.

An experiment was conducted to determine the effects of low and high metabolizable protein (MP) diets when fed for ad libitum and controlled intake during the prepartum period on postpartum lactation performance and feeding behavior of dairy cows. Thirty-six multiparous Holstein cows were blocked by parity, expected calving date, and previous lactation milk yield at -21 d relative to expected calving and were randomly assigned to 1 of 4 close-up period dietary treatments providing low MP (LMP) or high MP (HMP) diets with controlled intake (CNI) or ad libitum intake (ALI). The concentrations of MP were 65 and 90 g/kg dry matter for LMP and HMP diets, respectively, whereas intake was controlled to supply 100 and 160% of the NRC (2001) energy requirements for CNI and ALI groups, respectively. The concentration of net energy for lactation (NEL) in the treatment diets was 1.50 Mcal/kg. All cows were fed a similar lactation diet after calving (1.50 Mcal/kg of NEL and 83.3 g/kg of MP). The HMP diet increased dry matter intake during the first 3 wk and tended to increase dry matter intake over the 9 wk of lactation. Meal size and eating rate increased in the ALI cows during the prepartum period. Meal frequency increased with the HMP diet during the postpartum period. Milk yield increased by 15.2% with the HMP diet over the 9 wk of lactation. The HMP diet increased energy-corrected milk (ECM) yield in CNI versus ALI cows, whereas the LMP diet increased ECM yield in ALI versus CNI cows over the 9 wk of lactation. The increase in ECM yield of LMP-ALI versus LMP-CNI cows was supported by greater body condition loss and serum ß-hydroxybutyrate over the 9 wk of lactation. Taken together, these data indicate that prepartum controlled intake of a high protein diet can provide the benefits of both strategies.

Comparison of oil and fat supplementation on lactation performance of Nili Ravi buffaloes.

The effects of feeding rumen-inert fat sources on production responses of lactating dairy cows have been well reported but less thoroughly described in lactating dairy buffalo. The objective of this study was to investigate the effect of oil and 2 different rumen-inert fat sources on dry matter intake, milk yield, milk composition, and milk fatty acid (FA) profile in Nili Ravi buffalo. Twelve multiparous mid-lactating Nili Ravi buffaloes received 4 treatments in a 4 × 4 Latin square design with a period length of 21 d. The treatments were (1) the basal diet without supplementation of oil or fats (CTRL), (2) the basal diet supplemented with canola oil (CO), (3) the basal diet supplemented with calcium salts of palm FA (Ca-FA), and (4) the basal diet supplemented with high palmitic acid (PA). Dry matter intake was decreased by 4.4% in the CO compared with Ca-FA and PA. Milk yield and milk fat yield were increased by 7.8 and 14.3%, respectively, in CO, Ca-FA, and PA compared with the CTRL. Milk fat content increased by 7.5%, whereas milk fat yield tended to increase with the supplementation of Ca-FA and PA compared with CO. No effect on milk yield and milk composition was observed in Ca-FA versus PA treatments. The yield of medium-chain FA was increased by Ca-FA and PA versus CO. The CO treatment increased the yield of long-chain FA compared with Ca-FA and PA treatments. Plasma glucose level was higher in CO, Ca-FA, and PA compared with the CTRL. In conclusion, feeding rumen-inert fats in the lactating buffalo diet proved to be a useful strategy to increase the 3.5% fat-corrected milk yield due to the higher milk fat content in this study.