Incidence of clinical mastitis and its influence on reproductive performance of dairy cows

الملخص EN

The objectives of this study were to determine the incidence of clinical mastitis (CM) in relation to some risk factors and its impact on reproductive performance of Holstein cows.

Lactation records (n = 1875) were obtained from Dina farms covering the period between 2013 and 2016.

One third of cows (647/1875) had contracted at least one episode of CM throughout the entire lactation.

Frequency of CM decreased progressively with the month of lactation, and approximately half of the cases occurred within the first three months postpartum.

Incidence decreased (P<0.001) with level of milk yield, but increased (P<0.001) with parity.

CM significantly (P<0.05) increased calving to first estrus (+ 7.7 days), and to calving first insemination intervals (+6.5 days) compared to non-affected ones.

Furthermore, cows contracted CM before conception required 31 days more and +0.47 inseminations to conceive than cows without mastitis.

In brief, CM has a negative impact on reproductive performance of Holstein cows, and its occurrence is associated with level of milk yield, lactation order and stage of lactation.