Effect of melatonin implants on somatic cell counts in dairy goats

Milk industry, consumers, and public health organizations demand high quality standards. Somatic cell count (SCC) is one of the most important quality indicators, which is related to immune cells function and oxidative metabolism in the udder. Melatonin is known to play a positive role in oxidative metabolism. This work evaluates the possible efficacy of melatonin implants to reduce SCC in dairy goats. Sixty milking goats from one commercial dairy farm of the Verata breed, located in the South-West of Spain, were randomly allotted to two groups: implanted group (received a subcutaneous implant of 18mg melatonin in the pinna of the right ear in the beginning of lactation) and control group (not implanted). During the lactation the animals in the experiment were under surveillance to check the occurrence of clinical mastitis confirmed by bacteriological procedures. Blood and milk samples were taken 3 days after kidding and then 4 times more at monthly intervals. The melatonin administration increased significantly blood glutathione peroxidase (GSHPx), glutathione reductase (GR) and superoxide dismutase (SOD) activities in the implanted group at certain moments of the experiment. Although no significant differences were found for milk composition, SCC was significantly lower in the implanted group than in the control group in the middle of lactation. Therefore, the use of melatonin implants, in addition to reproductive benefits, could improve milk quality through decreasing SCC in dairy goats.