[Effect of puerperal mastitis in primiparous cows on milk production, cell count and culling]

A retrospective cohort study was performed to investigate the effect of clinical mastitis in heifers during the first week post partum (p.p.) on subsequent health and productivity. Primiparous cows that had calved between August 15th, 1996 and August 14th, 1997 (n = 1389) were included in the study. Milk samples were collected from each quarter post partum prior to first milking. The predominant group of bacteria found were Staphylococcus spp. (69%) followed by Streptococcus spp.(12%) and E. coli (5%). Intramammary infections at calving increased the risk of clinical mastitis within the first week p.p. The cow incidence of mastitis until day 7 p. p. was 38%. Cows were classified into three groups. Group 1: Animals with clinical mastitis prior to calving (n = 35); Group 2: Animals with clinical mastitis between calving and 7 days p. p. (n = 503); Group 3: Animals without mastitis until 7 days p. p. (n = 851). Mastitis prior to parturition and mastitis within the first week p.p. increased the risk of further cases of mastitis and culling during the first 45 days of lactation. Milk yield of Group 2 was lower and somatic cell counts were higher than in Group 3.