Effective breeding management is a crucial tool to enhance the reproductive and productive performance of dairy cattle. To achieve this, regular monitoring of their reproductive status is important. The aims of this study were to monitor the reproductive status of crossbred dairy cattle based on progesterone (P4) concentration in serum, whole milk, saliva and urine, and estradiol in serum using quantitative laboratory ELISA tests, and to document hormonal profiles at different reproductive stages. Three hundred and thirty-six (336) crossbred (Holstein Friesian x Zebu) dairy cattle (232 cows and 104 heifers) from 47 dairy farms owned by smallholder or organized commercial dairy farmers were included in the study. Matched blood, milk and saliva samples were collected twice at 11-day intervals at afternoon milking, while urine was collected just once. Serum was separated within 48 hr of blood collection. All samples were stored at -80oC until assayed. In both cows and heifers, P4 was higher during pregnancy than in other reproductive conditions. Estradiol was higher during estrus than at other reproductive stages. Estradiol levels were significantly higher (p<0.05) in estrus cows compared with heifers. The mean level of P4 in serum strongly correlated with the value in milk (r = 0.6368, P< 0.0001), however there was no correlation in P4 concentration between serum and saliva or between P4 in serum and in urine. Hence, determination of P4 in serum and milk using an ELISA test is a reliable and precise method to monitor reproductive status in crossbred dairy cattle.
- Reproductive success