Data/hora: 10/06/2024 18:03:06

Biblioteca(s): | Embrapa Caprinos e Ovinos.
Data corrente: | 01/08/1992
Data da última atualização: | 04/12/2023
Autoria: | ARMSTRONG, D. T.; PFITZNER, A. P.; PORTER, K. J.; WARNES, G. M.; JANSON, P. O.; SEAMARK, R. F.
Título: | Ovarian responses of anoestrous goats to stimulation with pregnant mare serum gonadotrophin.
Ano de publicação: | 1982
Fonte/Imprenta: | Animal Reproduction Science, v. 5, n. 1, p. 15-23, 1982.
DOI: | https://doi.org/10.1016/0378-4320(82)90033-1
Idioma: | Inglês
Conteúdo: | Abstract: Ovulation has been induced in feral goats before the onset of the breeding season by treatments with pregnant mare serum gonadotrophin (PMSG) combined with a synthetic progestagen (6α-methyl-17α-acetoxyprogesterone) administered via intravaginal pessary. Four hundred I.U. PMSG induced mean ovulation rates of 2–3 follicles per doe, whether administered at the same time as, or 2 days before, removal of the progestagen pessary. One-thousand I.U. PMSG was slightly more effective in inducing ovulation, but this was accompanied by a highly variable degree of stimulation of excessive numbers of follicles which occasionally luteinized but did not ovulate. There was a high correlation between the number of large unovulated follicles and the serum levels of oestradiol-17β observed around the time of ovulation in animals on the 1000 I.U. PMSG dosage. In these animals, oestradiol levels remained high throughout the early luteal phase, reaching maximal values at 7 days after PMSG administration. Copora lutea were not maintained in animals which ovulated following administration of PMSG 2 days before progestagen withdrawal. Administration of 250 I.U. human chorionic gonadotrophin (HCG) at the onset of oestrus failed to improve ovulation rates following 1000 I.U. PMSG or to decrease incidence of large unovulated follicles. Administration of 50 μg luteinizing hormone-releasing hormone (LH-RH) at the onset of oestrus significantly decreased the incidence of ovulation, and markedly increased the incidence of large unovulated follicles observed at laparotomy.
Palavras-Chave: | Anestro; PMSG.
Thesagro: | Caprino; Indução; Ovulação; Reprodução.
Thesaurus Nal: | Breeding season; Ovulation; Reproduction; Seasons; Sheep.
Categoria do assunto: | L Ciência Animal e Produtos de Origem Animal
Registro original: | Embrapa Caprinos e Ovinos (CNPC)
Exemplares: | CNPC - (8396-1) - ADD - AP - DD -  -  -  - DIS