Effects of supplementation with Biocholine Powder® on productive, metabolic and reproductive parameters in grazing dairy cows during the transition period

Abstract

The aim of the present study was to evaluate the effects of supplementation with rumen-protected choline (CPR) on milk production and composition, reproductive and metabolic parameters, and immune response of grazing dairy cows. Twenty Holstein-Friesian multiparous cows that calved in spring 2017 were fed a pre-partum diet and allocated into two treatment groups 21 days pre-calving: i) supplemented with CPR, (15 g day^-1) mixed with the feed until d 21 postpartum; ii) the non-supplemented group was considered as the control. There was no effect of supplementation with CPR on milk production throughout the complete lactation period. The supplemented group had a higher production at 21 d (P = 0.018) and showed a trend to higher production during the first 40 days of lactation (P = 0.051). Somatic cell count and somatic cell score (SCS) were higher for the non-supplemented group (P = 0.01). Regarding the reproductive indicators, the CPR-supplemented cows tended to start an oestrus phase 14.2 + 7.1 days before the control group (P = 0.063). There was an interaction between treatment and weeks after parturition for BCS, where the CPR treatment showed recovery on week 3 postpartum, whereas for control cows it continued decreasing (P = 0.061). The results of the metabolic indicators suggest that cows in the control group, as well as those in CPR treatment, did not show a severe negative energy balance with a high risk of metabolic disorders and showed better fertility based on days to first oestrus.