Effects of cooked molasses licking block supplementation pre- and post-partum on feed intake, suckling lamb performance, milk yield and milk quality in dairy sheep. Part 1

Abstract

This study tested the nutritional benefit of a supplement offered freely to dairy sheep over a period from 60 days before lambing to 60 days after lambing, at stall and grazing. Thirty Sarda dairy sheep on Day 90 of gestation, homogeneous for age, parity number, bodyweight (BW) and body condition score (BCS), were allocated to one of two groups: control (Ctr) or treated (Cry). Over 120 days, both groups received ryegrass hay and concentrate indoors. After weaning, the ewes also had access to pasture for 6 h/day. Throughout the experimental period, the Cry group had ad libitum access to a cooked molasses licking block. No significant differences were observed between the groups in forage, concentrate and total DM intake. During the experiment, the reduction in BCS in early lactation tended to be slower in the Cry than in Ctr group (Ptrend < 0.09), whereas no significant effects were seen on BW. Lamb performance tended to be improved by Cry in terms of liveweight of litter size per sheep (9.65 vs 8.22 kg for Cry and Ctr, respectively; P < 0.07), whereas no significant effects were observed on milk yield and composition, except for a trend for increased fat content in the Cry versus Ctr group (6.15% vs 5.95%, respectively; P < 0.08). Cry ewes had higher blood cholesterol concentrations than did Ctr ewes (1.96 vs 1.63 mmol/L; P < 0.01). Because there were no differences between feed intake at stall and the estimated total DM intake at stall and during grazing between the two groups, the better performance of the Cry group could be explained by an increase of feed use efficiency at the digestive and/or metabolic level.