Increased dietary energy alters follicle dynamics and wave patterns in heifers.

Autor:	Domingues RR; Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA.; Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, Wisconsin, USA.; Eutheria Foundation, Cross Plains, Wisconsin, USA., Ginther OJ; Eutheria Foundation, Cross Plains, Wisconsin, USA.; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA., Toledo MZ; Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA., Wiltbank MC; Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA.; Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Jazyk:	angličtina
Zdroj:	Reproduction (Cambridge, England) [Reproduction] 2020 Dec; Vol. 160 (6), pp. 943-953.
DOI:	10.1530/REP-20-0362
Abstrakt:	Understanding the impacts of nutrition on reproductive physiology in cattle are fundamental to improve reproductive efficiency for animals under different nutritional conditions. Starting on Day 0 (day of ovulation) until next ovulation, Holstein heifers (n = 24) were fed: low energy diet (ad libitum grass hay; LED) and high energy diet (ad libitum grass hay + concentrate supplement; HED). Heifers on HED gained more weight (average daily gain: 0.824 ± 0.07 vs 0.598 ± 0.09 kg/day) and had increased insulin concentrations. The dominant follicle of wave 1 in HED had greater growth rate overall from Days 0 to 8 and on Days 6-7 and 8-9 and started atresia later. The dominant follicle of wave 2 in HED had greater growth rate overall from Day 9 to 18 and on Days 14-15 and 15-16. In two-wave patterns, there was no difference in estradiol or progesterone concentrations but concentrations of FSH were lower in HED on Days 15 and 16. Estradiol concentrations increased earlier in two-wave patterns in association with earlier luteolysis. The frequency of two follicular waves was greater in HED than LED (11/12 vs 6/11; 92.7% vs 54.5%). In conclusion, an acute increase in dietary energy altered not only growth rate of the dominant follicle but also follicular wave pattern in heifers by increasing frequency of two follicular waves. The hypotheses were supported that an acute increase in dietary energy (1) prolongs growth period of dominant follicles and (2) alters follicular wave pattern in heifers.
Databáze:	MEDLINE
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