Melatonin Treatment at Dry-off Reduces Postpartum Shedding of Coccidia in Primiparous Dairy Cows and Their Calves

Coccidiosis is a protozoan disease that causes diarrhea in cattle. This study examines the impact of treating pregnant cows at dry-off with melatonin on postpartum coccidia excretion in dams and their calves. The study population comprised 106 primiparous lactating dairy cows: 53 controls and 53 receiving melatonin on days 220-226 of gestation, plus 99 calves: 52 born from control and 47 from treated dams. Feces samples were collected from each dam on gestation days 220-226 and on days 10-16 and 30-36 postpartum; and from each calf on days 10-16 and 30-36 of age. Postpartum rates of high excretion of oocysts per gram (OPG) (feces counts > 5000) were significantly lower (<i>p</i> < 0.01) in treated than control dams. Low excretion rates of OPG (<2000) were significantly higher (<i>p</i> < 0.01) in the melatonin treatment than control groups in dams on days 30-36 of lactation and in calves at 10-16 and 30-36 days of life. In conclusion, melatonin treatment in lactating cows at dry-off reduced coccidia shedding in dams and their calves during the early postpartum period.