Milk cellularity and intramammary infections in primiparous and multiparous Lacaune ewes during early lactation

Abstract

Despite the vast literature on postpartum mastitis in cattle, there is a demand for and lack of studies on the cellularity dynamics and cellular populations in milk and the occurrence of mastitis in ewes during the postpartum period. Thus, the aim of the present study was to evaluate the dynamics of cellularity in milk/colostrum and of mastitis in primiparous and multiparous Lacaune ewes during early lactation. For this purpose, 492 milk/colostrum samples were collected from the udder halves of 20 primiparous ewes and 21 multiparous ewes at the following six time points: day of parturition (T1) and one day (T2), three days (T3), seven days (T4), 15 days (T5), and 30 days (T6) after parturition. The milk and colostrum samples were subjected to microbiological examination, microscopic and automatic somatic cell counts (SCCs), differential somatic cell counts, and the California Mastitis test (CMT). The multiparous ewes had a higher prevalence of intramammary infections than the primiparous ewes during the postpartum period. Non-aureus staphylococci bacteria were the main mastitis etiological agents isolated in the present study. Furthermore, one of the most important findings of our study was that 35% of the udder halves of the primiparous ewes were infected at parturition, suggesting potential concerns for mastitis control programs. Finally, the SCC did not appear to be a good indicator of inflammation during early lactation because this measure was influenced by the parity and the sampling period. Moreover, the predictive values of the CMT and neutrophil counts were slightly better than those of the SCC during the immediate postpartum period.