Abstract
The research aims to study the dynamics of reproductive system pathologies in mares of Kazakh and Mugalzhar horse breeds and their impact on the reproductive traits of the breeding stock. The object of the research was horses of the Kazakh and Mugalzhar breeds. The formation of experimental groups was carried out using the pair-analog method. It was found that the frequency of detection of infertile mares is 13.8-25.0%. Subinvolution of the uterus from the total number of infertile mares is 8.3-10.7%, endometritis - 16.6-23.3%, atony and hypotonia of the uterus - 8.3-13.3%, ovarian diseases - 19.6-43.4%, other diseases - 10.0-39.4%. The pregnancy rate of mares of the Kazakh and Mugalzhar breeds was 78.8%. The frequency of abortions, weakly born, and stillborn foals was 2.8%. Successful foaling was 76.0%. It was established that successful foaling in mares under 5 years old is 65.6%, 6-9 years old - 79.5%, and 10 years and older - 74.6%. Pregnancy rates are lowest in mares under 5 years of age (74.4%), compared to 6-9 years of age (88.0%) and 10 years of age and older (82.0%). Milk productivity analysis of first-lactation mares revealed significantly higher yields on farms specializing in mare's milk production, accompanied by slight improvements in fat and protein content. The findings highlight the strong influence of management practices, nutritional status, and timely reproductive monitoring on the reproductive success of local horse breeds.