Low numbers of ovarian follicles ≥3 mm in diameter are associated with low fertility in dairy cows
Open Access
- 1 May 2012
- journal article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 95 (5), 2355-2361
- https://doi.org/10.3168/jds.2011-4325
Abstract
The total number of ovarian follicles ≥ 3mm in diameter (antral follicle count, AFC) during follicular waves varies among cattle of similar age, but AFC is highly repeatable within individuals. We hypothesized that lower AFC could be associated with reduced fertility in cattle. The AFC was assessed by ultrasonography for 2 d consecutively during the first wave of follicular growth of the estrous cycle, 4.6±1.43 d (mean ± SD) after estrus, in 306 Holstein-Friesian dairy cows approximately 70 d postpartum. Cows were classified into 3 groups based on AFC: low (AFC ≤15), intermediate (AFC=16 to 24), and high (AFC ≥25). During the cycle in which AFC was assessed and in subsequent cycles, cows were artificially inseminated (AI) following detection of estrus, and pregnancy status was assessed using ultrasonography. Cows with high AFC had 3.34 times greater odds of being pregnant at the end of the breeding season compared with cows with low AFC; the odds of a successful pregnancy at first service were 1.75 times greater in the intermediate compared with the low group. The predicted probability of a successful pregnancy by the end of the breeding period (length of breeding season was 86±16.3 d) was 94, 88, and 84% for the high, intermediate, and low AFC groups, respectively. No difference was evident among groups in 21-d submission rate (proportion of all cows detected in estrus and submitted for AI in the first 21 d of the breeding season), but the interval from calving to conception was shorter in the high (109.5±5.1 d) versus low (117.1±4 d) group, and animals with intermediate AFC received fewer services during the breeding season (2.3±0.1) compared with animals with low AFC (2.7±0.1). Lactating cows with ≤15 ovarian follicles have lower reproductive performance compared with cows with higher numbers of follicles, but the existence of a positive association between high numbers of ovarian follicles and fertility is yet to be established.This publication has 22 references indexed in Scilit:
- Does size matter in females? An overview of the impact of the high variation in the ovarian reserve on ovarian function and fertility, utility of anti-Müllerian hormone as a diagnostic marker for fertility and causes of variation in the ovarian reserve in cattleReproduction, Fertility and Development, 2011
- Embryonic and Early Foetal Losses in Cattle and Other RuminantsReproduction in Domestic Animals, 2008
- Numbers of Antral Follicles During Follicular Waves in Cattle: Evidence for High Variation Among Animals, Very High Repeatability in Individuals, and an Inverse Association with Serum Follicle-Stimulating Hormone Concentrations1Biology of Reproduction, 2005
- Characteristics of Ovarian Follicle Development in Domestic AnimalsReproduction in Domestic Animals, 2003
- Scanning the Future—Ultrasonography as a Reproductive Management Tool for Dairy CattleJournal of Dairy Science, 2002
- Follicular waves and circulating gonadotrophins in 8-month-old prepubertal heifersReproduction, 1994
- Association between surges of follicle-stimulating hormone and the emergence of follicular waves in heifersReproduction, 1992
- Composition and characteristics of follicular waves during the bovine estrous cycleAnimal Reproduction Science, 1989
- Ovarian Characteristics and Reproductive Performance of the Aged Cow1Biology of Reproduction, 1976
- Development and Senescence of the Postnatal Bovine OvaryJournal of Animal Science, 1966