Published in Scientific Papers. Series D. Animal Science, Vol. LXII, Issue 1
Written by Constantin GĂVAN
In cattles the small antral growing follicles develop from a reserve of primordial follicles constituted early in life. The antral follicle count (AFC, follicles ≥ 3 mm in diameter) is determined by ovarian ultrasound measurement. In this study 13 to16 months old Holstein Friesian heifers were subjected to a single ultrasound measurement of the number of follicles ≥3 mm in diameter. Heifers were classified into a low (≤ 5 follicles) mid (16-24 follicles) and high (≥25 follicles) follicle number group (FNG). We then compared the reproductive and productive performances at the end of first lactation. Results showed that heifers in the high FNG had a higher pregnancy rate, a shorter calving to conception interval, and a higher culling rate, compared with heifers in the low FNG. Because this study was made in a single herd with limited animal numbers (n=100) it is premature to make an industry-wide recommendation to select the dairy heifers in a herd based on single AFC measurements.
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