Does melatonin treatment during lactation influence milk production in Lacaune and Assaf ewes?

Abstract

To determine whether treatment with melatonin during lactation harms milk production, two experiments were performed. In Experiment 1, 188 Lacaune ewes, lambed between September 12 and November 1 were used, and in Experiment 2, 124 Assaf ewes that lambed between November 14 and January 11. In Experiment 1, a first milk record was obtained on February 11, which was used to divide the animals into two groups, M and C. On March 11, a subcutaneous melatonin implant was administered to M animals (n=93), and the rest (n=95) corresponded to the Control Group (C). In Experiment 2, the first milk record was at weaning (January 5) and, on February 15, ewes were divided into M (n=90) and C (n=34). From that date until dry-off, monthly milk records were obtained. In both experiments, melatonin treatment significantly increased the number of lambs produced, and no detrimental effects on milk production were detected. In conclusion, the use of melatonin to improve reproduction in dairy sheep does not interfere with milk production. Moreover, an increase in the number of lambs produced, and the greater number of ewes that can be milked in the following period because of exogenous melatonin can provide economical benefits to farms.