J. E. MITEV, Zh. I. GERGOVSKA and Tch. M. MITEVA
Trakia University, Agricultural Faculty, BG - 6000 Stara Zagora, Bulgaria
MITEV, J. E., Zh. I. GERGOVSKA and Tch. M. MITEVA, 2012. Effect of teat end hyperkeratosis on milk somatic cell counts in Bulgarian Black-and-White dairy cattle. Bulg. J. Agric. Sci., 18: 451-454
The aim of the study was to investigate the relationship between teat end hyperkeratosis score and somatic cell counts in milk in dairy cattle at different lactations. Five hundred Holstein cattle from 16 farms were included in the research. The Teat end hyperkeratosis was evaluated with a four-point scoring system. The parity number and the position of teats (front/rear) had a significant effect on teat end hyperkeratosis score and somatic cell counts in milk (P<0.001). The presence of keratin deposits and alterations of teat ends in cows with score 3 and 4 were related to higher somatic cell counts, 195.7 thousand/ml and 235.4 thousand/ml, respectively, which is at and over the threshold indicating a bacterial infections. Rear teats exhibited a higher proportion of teat end hyperkeratosis score 3 (41.2 vs 28.8%) and score 4 (1.2% vs 0%), and higher somatic cell counts than front ones. Cows at their 4th and 5th lactation demonstrated higher percentage of teats with hyperkeratosis scores 3 and 4 and respectively, higher somatic cell counts, compared to second and third lactation cows.