Effect of undegradable protein amount fed prepartum on postpartum production in first lactation Holstein cows.

Twenty primigravid Holsteins were paired by expected calving date and estimated producing ability and assigned randomly to one of two diets to determine the effect of prepartum supplemented undegradable protein on subsequent productive performance. Diets were isocaloric, isonitrogenous for degradable protein and differed in undegradable protein content. Prepartum diets were fed for ad libitum intake for 3 wk prior to calving. Following parturition, a single diet was offered for ad libitum intake. Cows did not differ in initial BW or body condition score. Body condition score, BW, and milk composition were measured weekly, starting at calving through the first 6 wk of lactation, Milk production was measured daily. Prepartum diet did not influence calf birth weight or mean prepartum DMI. Prepartum diet containing increased undegradable protein improved body condition score at calving through wk 6 postcalving and increased milk protein percentage. Mean daily protein production was consistently greater for the prepartum diet with additional undegradable protein. Milk, FCM, and milk fat were not influenced by prepartum diet. Supplemental undegradable protein prepartum may improve postpartum performance by minimizing mobilization of maternal labile protein pools to meet fetal and maternal growth requirements in late gestation.