Impact of A Dietary Citrus Extract on The Behavior and Production of Lactating Dairy Cows Following Regrouping

The objective of this study was to determine if feeding a sensory functional feed additive (mainly based on Citrus sinensis extracts) reduces the negative impact of regrouping of lactating dairy cows. Thirty-two, mid-lactation Holstein dairy cows were enrolled as focal cows in this study and housed individually in a tie-stall facility where they were assigned to 1 of 2 treatment diets: 1) control total mixed ration, or 2) control total mixed ration with 4 g/d of citrus extract (Phodé, Terssac, France). Cows were fed their experimental diets for 7 d in the tie-stall facility, then moved to 1 of 2 experimental free-stall pens for a period of 7 d, where they remained on the same treatment diet as provided in the tie-stall facility. Compared with their baseline, primiparous control cows had decreased rumination time on d 1 and 2 and decreased lying time on d 1. In contrast, primiparous cows fed the CE diet did not experience any decrease in rumination and lying time. Primiparous cows fed CE had greater feeding time in the first 2 d after regrouping, while primiparous control cows had greater idle standing time after regrouping. Primiparous CE cows tended to be the recipient of more aggressive interactions at the feed bunk after regrouping than primiparous control cows. However, primiparous CE cows initiated less total competitive behavior after regrouping. Further, primiparous CE cows had greater milk yield as compared with primiparous control cows across the 7 d after regrouping. CE supplementation had little effect on the behavior or production response after regrouping of multiparous cows, who were more experienced with this social stressor. The results indicate that feeding this CE additive to naïve primiparous dairy cows may reduce the negative effects of regrouping on behavior, while promoting greater milk production, after regrouping.

Key words: citrus extract, social regrouping, behavior