Association between clinical and subclinical mastitis and reproductive performance of cows at Nottingham dairy centre

Abstract

Clinical and subclinical mastitis regarded as important diseases causes a reduction in reproductive performance in dairy cows in the UK during the last decade. This study was aimed to assess the association between clinical mastitis, subclinical mastitis and the reproductive performance of cows. Data from 184 multiparous Holstein dairy cows were collected. Binomial logistic regression used to determine the incidence rate of clinical mastitis and subclinical mastitis between parity, calving year and seasons of the year. Linear mixed model used to determine the effect of clinical and subclinical mastitis on reproductive performance. The association between clinical or subclinical mastitis and the probability of a cow to get pregnant at 1st, 2nd or 3rd service was evaluated using binomial logistic regression. The same model used to illustrate the probability of a cow getting pregnant from 30-60 days postpartum or 61-90 days postpartum. The incidence of clinical mastitis was different between calving years (P<0.01). Cow with clinical mastitis or subclinical mastitis had longer calving to first service interval, calving to conception interval (P<0.05). Cows clinical mastitis had a lower rate to get pregnant within 20-30 days postpartum compared to healthy cows (P<0.05). Cows with higher somatic cells count, (especially cows with greater than 399,000 cells/mL of milk), had a higher number of services compared to cows with a lower number of individual cow somatic cell counts. The study concluded that both clinical and subclinical mastitis have a relationship with a reduction in reproductive performance in high yielding dairy cows.

Keywords

• clinical mastitis
• somatic cells count
• reproductive performance
• dairy cows