LUTEINIZING HORMONE SECRETION IN NELLORE HEIFER’S AFTER WEANING TO FIRST OVULATION
DOI:
https://doi.org/10.5216/cab.v10i4.3788Keywords:
Animal reproductionAbstract
The aim was to evaluate the LH secretion in B. indicus heifers, on the presence or absence of gonadal steroid, generating information about the mechanisms evolved on sexual maturation in Nellore heifers. LH and progesterone concentration were quantified by RIA. First ovulation was determined by plasma progesterone concentration (>1 ng/ml). Greater mean LH concentrations was observed in ovariectomized (OVX; P?0.05) compared to intact heifers (INT). Mean LH concentration increased (P?0.05) during the sexual maturation, in both intact and ovariectomized heifers. The number of peaks was higher (P?0.05) in ovariectomized heifer. The results suggest decrease in estradiol hypothalamus negative feedback during Nellore heifer’s sexual maturation. It was possible to conclude that in pre-pubertal Nellore heifers the increase on positive gonadal steroids feedback was necessary to increase LH secretion before first ovulation.KEY WORDS: Cattle, endocrinology, hypothalamus, puberty, steroids.
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Published
2009-12-20
How to Cite
CARDOSO, D.; FERREIRA, G. F.; NOGUEIRA, G. P. LUTEINIZING HORMONE SECRETION IN NELLORE HEIFER’S AFTER WEANING TO FIRST OVULATION. Brazilian Animal Science/ Ciência Animal Brasileira, Goiânia, v. 10, n. 4, p. 1277–1284, 2009. DOI: 10.5216/cab.v10i4.3788. Disponível em: https://revistas.ufg.br/vet/article/view/3788. Acesso em: 21 nov. 2024.
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Veterinary Medicine
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