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Feeding rumen-protected lysine prepartum increased energy-corrected milk in Holstein cows during early lactation.

L. K. Fehlberg

Abstract:

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Feeding rumen-protected lysine prepartum increased energy-corrected milk in Holstein cows during early lactation.
L. K. Fehlberg*1, A. R. Guadagnin1, B. L. Thomas1, Y. Sugimoto2, I. Shinzato2, F. C. Cardoso1. 1University of Illinois Urbana, IL, 2Ajinomoto Co. Inc Tokyo, Japan.

Balancing for AA in the diet can optimize milk yield and composition; however, there is little information on the requirement of AA, specifically Lys, during the transition period. This experiment was conducted to determine the effects of feeding rumen-protected Lys (RPL; AjiPro-L Generation 3, Ajinomoto Heartland Inc., Chicago, IL) prepartum (0.54%DM of TMR), postpartum (0.395%DM of TMR), or both on performance. Seventy-five multiparous Holstein cows, blocked by parity, previous 305-d mature-equivalent milk production, expected calving date, and body condition score during the far-off dry period were assigned to 1 of 4 dietary treatments in a randomized, complete block design with a crossover of diet with RPL (L) or without (C). Treatments consisted of TMR with RPL prepartum and postpartum (LL), with RPL prepartum and without postpartum (LC), without RPL prepartum and with postpartum (CL), and without RPL prepartum and postpartum (CC). Cows were milked 2 � per d and milk samples were taken on 7 � 1.3, 14 � 1.4, and 28 � 1.1 d relative to calving. Milk yield and dry matter intake (DMI) were obtained daily. Statistical analyses were performed using MIXED procedure of SAS. Cows in L had greater (P = 0.03) BW (823 � 3kg for wk −2 and 785 � 3kg for wk −1) during the −2 wk before calving compared with those in C (814 � 3kg for wk −2 and 775 � 3kg for wk −1). Postpartum BW (717 � 6kg) was greater (P = 0.05) and DMI (18.12 � 0.74kg) tended (P = 0.08) to be greater for cows in LL and LC compared with those that were in CL and CC (706.5 � 6 and 16.84 � 0.74 kg, respectively). Energy-corrected milk (48.7 � 1.9 kg/d), 3.5% fat-corrected milk (50.1 � 2.1 kg/d), milk fat (1.93 � 0.09 kg/d), milk true protein (1.41 � 0.05 kg/d), milk casein (0.64 � 0.04 kg/d), and milk lactose yields (2.07 � 0.08 kg/d) were greater (P ≤ 0.04) for cows in LL and LC compared with those that were in CL and CC (44.2 � 1.9, 45.2 � 2.1, 1.71 � 0.09, 1.30 � 0.05, 0.54 � 0.04, 1.88 � 0.08 kg/d, respectively). In conclusion, cows that consumed RPL prepartum tended to increase DMI postpartum and increased energy-corrected milk and milk component yields.

Keywords: lysine, milk protein, transition period.