SOMATIC CELL COUNT IN HOLSTEIN COW MILK AND ITS ASSOCIATION WITH REPRODUCTIVE PERFORMANCE

Abstract

This study examined the somatic cell count (SCC) in the milk of Holstein cows and evaluated its association with reproductive performance. The relevance of the study is determined by the fact that elevated SCC is an important indicator of udder health, the risk of subclinical mastitis, reduced milk quality, and possible impairment of reproductive function in dairy cows. The research was conducted at the Baiserke-Agro LLP dairy farm in Almaty region using test-day milk recording data from 515 cows and calving records. Somatic cell count was determined using a Fossomatic FC analyzer; the results were expressed as thousand cells/mL of milk. The animals were classified by SCC categories and age groups, after which the prevalence of elevated SCC, age-related changes in this indicator, and its association with reproductive parameters were assessed. It was found that 67.6% of the animals had SCC levels exceeding 150 thousand cells/mL, while 23.7% of cows had values above 1000 thousand cells/mL. As cow age increased, the proportion of animals with high SCC also rose; the correlation between age and somatic cell count was r ≈ 0.42. According to calving records, 705 calving intervals were calculated; the mean duration was 461.8 days, and the median was 419 days. Elevated SCC was associated with poorer reproductive indicators, including longer calving intervals and service periods. Thus, the cows studied showed a tendency for the insemination index to increase with increasing somatic cell count in milk, which is an undesirable phenomenon for dairy farms. The obtained results confirm the practical importance of regular SCC monitoring for early identification of at-risk animals, mastitis prevention, and improvement of reproductive efficiency in dairy herds.