Effect of Season on Pregnancy Rates, Milk Progesterone, and Milk Melatonin Profiles in Water Buffalo Reared in Canada

Abstract

Having recently been introduced to Canada, water buffalo products have a growing market demand. While water buffaloes are seasonal breeders in some environments, the impact of season on estrus patterns in Canada is unknown. Pregnancy rates for buffaloes artificially inseminated in different seasons following synchronization or natural estrus were calculated. Milk samples were used to determine variation in progesterone and melatonin during summer (long days) and winter (short days). Milk was collected from randomly selected buffaloes and hormones were measured via enzyme-linked immunosorbent assays (ELISA). Spring and summer pregnancy rates were lower than in fall and winter. Spring and summer samples showed low progesterone concentrations with abrupt rise and fall. Fall and winter samples showed high progesterone with prolonged peaks and 20-22-day estrous cycles. No significant trend was observed in melatonin levels. Results indicate breeding seasons in Canada are fall and winter while low breeding seasons are spring and summer.