Effects of a sorbitol-containing additive fed to dairy cows for 30 days postpartum.

The objective of this study was to determine the effects of early postpartum supplementation of Rally®, a sorbitol-containing feed additive (RAL), on lactation performance and automatic milking system (AMS) metrics on a commercial dairy farm. Multiparous (MT) and primiparous (PP) Holstein cows were randomly assigned to either RAL supplementation (570 g/d RAL; RAL-MT, n = 75, RAL-PP, n = 34) or control (CTL-MT, n = 72; CTL-PP, n = 38). The RAL cows were supplemented from 1 to 30 d in milk via an automated feed dispenser in the AMS. Milk production and other metrics were recorded for 1 to 90 DIM. Outcomes were analyzed with a linear mixed effect model with repeated measures. Analyses were conducted separately for the 2 periods: supplementation (1-30 DIM) or post-supplementation (31-90 DIM). Multiparous cows fed RAL produced 3.52 ± 1.29 kg more ECM per day than CTL cows during the supplementation period. The number of refusal visits/d to the AMS (visits when was not time for cows to be milked) during the supplementation period was 0.66 fewer for multiparous cows fed RAL than CTL cows. Daily milk yield and ECM yield, and number of refusal visits/d were similar for primiparous cows fed RAL or CTL during the supplementation period. Multiparous cows fed RAL continued to produce 2.17 ± 1.11 kg more ECM per day than CTL cows during the post-supplementation period. Rumination time during the post- supplementation period was 12.5 min less for multiparous cows fed RAL than CTL cows. The number of refusal visits/d during the post-supplementation period was 0.59 fewer for multiparous cows fed RAL compared with CTL cows. Daily milk yield and ECM yield, rumination time, and number of refusal visits per day during the post-supplementation period were similar between primiparous cows fed RAL and CTL cows. The results from this study indicate that RAL supplementation during the first 30 DIM increased milk yields when fed to multiparous cows.