The influence of somatic cell count in milk on reproductive traits and production of Black-and-White cows

JUOZAITIENE, V., A. JUOZAITIS: The influence of somatic cell count in milk on reproductive traits and production of Black-and-White cows. Vet. arhiv 75, 407414, 2005. ABSTRACT The aim of this study was to estimate the relationships between somatic cell count in milk, reproduction traits and milk production of cows of the Black-and-White breed. The research was carried out on 412 herds of the active Black-and-White cattle population in Lithuania. Data on cows in the first three lactations during the period between 1998 and 2003 were used. Milk yield increased but lactation duration decreased with the increasing lactation number. The effect of lactation numbers on milk yield and dry period, as well as on calving interval, was found to be statistically significant (P<0.001). Insemination number, service period and calving interval decreased with the increasing lactation number. The best milk production and reproductive performance was obtained in the third lactation. The increase of SCC (from 100 000/mL to 800 000/mL and over) increased the number of inseminations per conception of Black-and-White cows (from 133.1 to 144.6%), service period (from 55.5 to 77.9%) and calving interval (from 11.6 to 17.7%) in the first three lactations. Correlation between the SCC log2 and milk yield was significantly negative (r = -0.35, P<0.01). Statistically significant (P<0.01) positive correlations ranging from 0.36 to 0.44 were found between the SCC log2 and the investigated reproductive traits.