Authors: ROBERT ZOBEL, SUZANA TKALCIC, WENDELL COLE
Abstract: The purpose of this study was to establish the fertility trends in dairy cows in Central Croatia and compare the trends and causes of infertility and subfertility during a 5-year period. A total of 12,060 Simmental cows and heifers were included in the study. The animals were examined by vaginoscopy, transrectal palpation, and ultrasonography on a regular basis. Fertility problems that included infertility and subfertility were diagnosed in 56.61% of all observed animals. The total number of animals diagnosed with subfertility increased and almost doubled by the end of the study period. Subfertility issues associated with anovulatory oestrus, delayed ovulation, and endometritis were 2 to 3 times more frequent at the end of the study period compared to the first year of the study. The number of animals with the repeat breeder syndrome diagnosis remained constant throughout the study. Anoestrus and cystic ovarian disease occurrence declined over time and were more than 50% reduced by the end of the study. Infertility was present in less than 1% of cows and did not change over time. In this study we recognised a rising trend of subfertility in Simmental cows in Central Croatia, primarily related to anovulatory oestrus, delayed ovulation, and endometritis.
Keywords: Cattle, infertility, subfertility, Croatia
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