27 research outputs found
Provincia de San Luis
Fil: Deletang, Luis F. Ministerio de Agricultura. DirecciĂłn General de Minas, GeologĂa e HidrologĂa; Argentina
THE USE OF GONADOTROPHIN RELEASING HORMONE (GnRH) ASSOCIATED WITH PROGESTAGEN FOR INDUCING OESTRUS IN SUCKLING COWS)
International audienc
Discovery releasing factor the growth hormon (GRF) and first biological results
Après la découverte du TRH, LHRH, Somatostatine et CRF, le GRF a été isolé et séquencé par R. Guillemin et coll. en 1982. La structure exacte des GRF murin, bovin, porcin et humain est connue. Les premiers résultats biologiques montrent la puissance et la spécificité de ce peptide vis-à -vis de la sécrétion d'hormone de croissance. Divers effets bénéfiques liés à la stimulation de 1 "ana bolisme protidique sont attendus.Discovery of the growth hormone releasing factor FIRST BIOLOGICAL RESULTS After the discovery of TRH, LHRH, Somatostatin and CRF, the Growth Hormone Releasing Factor has been isolated and sequency by R. Guillemin and al. in 1982. The exact structure of murine, bovine, porcine and human GRF are known. Early biological results show the potency and the specificity of this peptide toward Growth hormone secretion. Various benefits related to the resulting increase in protidic anabolism are expected
Effet d'un traitement à base de mélatonine sur les critères de reproduction de troupeaux ovins de race Tarasconnaise en lutte naturelle de printemps
National audienc
Effet d'un traitement à base de mélatonine sur les critères de reproduction de troupeaux ovins de race Tarasconnaise en lutte naturelle de printemps
National audienc
Utilisation des traitements lumineux et des implants de mélatonine chez les petits ruminants
National audienc
Control of oestrus with a progesterone intravaginal device (Prid®): comparison of 2 insertion durations
International audienc
Utilisation des traitements lumineux et des implants de mélatonine chez les petits ruminants
National audienc
The effect of GnRH treatment at the time of AI and 12 days later on reproductive performance of high producing dairy cows during the warm season in northeasten Spain.
It was hypothesized that gonadotropin-releasing hormone (GnRH) treatment at the time of insemination and 12 days later increases conception rates. The aim of the present study was to evaluate the effects of GnRH treatment at the time of insemination or at the time of insemination and 12 days later on reproductive performance during the warm season in high producing dairy cows. The effect of GnRH treatment on the incidence of subsequent twin pregnancies and pregnancy losses was also evaluated. Data were analyzed using logistic regression methods. Of the entire series of 1289 AI, 373 (29%) resulted in pregnancy. Three study groups were established to evaluate the effects of treatment on the conception rate: control (untreated cows, n = 431), GnRH-0 (cows receiving GnRH at AI, n = 429) or GnRH-0 + 12 (cows receiving GnRH at AI and at AI + 12 days, n = 429). Conception rates were 20.6% (89/431), 30.8% (132/429) and 35.4% (152/429) for animals receiving no treatment, GnRH at AI, and GnRH at AI and 12 days later, respectively. Based on the odds ratio, the probability of pregnancy was 0.80 and 0.46 times less likely for cows receiving treatment GnRH-0 and no treatment, respectively, than for cows receiving treatment GnRH-0 + 12 (reference). Of the 373 pregnant animals, 326 (87.4%) bore singletons and 47 (12.6%) carried twins. The effects of treatment on the dependent variables: twin pregnancy, additional corpus luteum and pregnancy loss were analyzed. Pregnancy loss between 38 and 90 days after insemination was registered in 30 (8%) cows: 17 (5.2%) in single and 13 (27.7%) in twin pregnancies. Fifty-six (15%) cows had an additional corpus luteum. No pregnancy losses were recorded in these cows. Treatment had no effect on the twin pregnancy rate. The treatment GnRH at AI and 12 days later increased the chances of an additional corpus luteum by a factor 3.7 (using the control group as reference). In conclusion, our results support the hypothesis that GnRH treatment at the time of insemination and 12 days later increases the conception rate in high producing dairy cows during the warm season. Although lower than double treatment, strong benefits were also registered following a single GnRH treatment at insemination. Under these conditions, treatment fails to affect the twin pregnancy rate yet increases the incidence of an additional corpus luteum in pregnant cows. © 2005 Elsevier Inc. All rights reserved
Etude de la réponse immunitaire observée chez les ovins et les caprins traités avec PMSG dans le cadre de l'insémination artificielle
National audienc