Influence of clinical mastitis during early lactation on reproductive performance of Jersey cows

The purpose of this study was to determine the influence of clinical mastitis on reproductive performance of high producing Jersey cows. Cows (n = 102) with clinical mastitis during the first 150 d of lactation were evaluated. Groups were balanced according to lactation number and days of lactation and subdivided as follows: group 1, clinical mastitis before first artificial insemination (AI) (n = 48); group 2, clinical mastitis between first Al and pregnancy (n 14); group 3, clinical mastitis after confirmed pregnancy (n = 40); and group 4, control cows (n = 103) with no clinical mastitis. No differences in reproductive performance were detected because of milk production or mastitis caused by Gram-positive or Gram-negative pathogens. The number of days to first AT was significantly greater for cows with clinical mastitis before first AT: (93.6 d) than for all other groups (71.0 d). Artificial inseminations per conception were significantly greater for cows with clinical mastitis after first Al (2.9) than for cows with clinical mastitis before first Al (1.6), cows with no clinical mastitis, or cows with clinical mastitis after confirmed pregnancy (1.7). The number of days to conception for cows with clinical mastitis after first Al (136.6 d) was significantly greater than that for control cows and that for cows that developed clinical mastitis after confirmed pregnancy (92.1 d). Clinical mastitis during early lactation markedly influenced reproductive performance of Jersey cows.