Dosage de l’hormone folliculo-stimulante (FSH) bovine par ELISA et son application aux études endocriniennes chez la vache

National audienc

Evaluation de colliers-activimètres pour la détection automatisée de chaleurs induites et synchronisées par effet mâle, dans l’objectif de pratiquer l’insémination chez les caprins

International audienc

Les traitements lumineux basés sur des jours « très longs » sont-ils une alternative à l’utilisation de mélatonine chez la chèvre?

International audienc

Nouveau traitement photopériodique pour synchroniser les ovulations par effet mâle en saison sexuelle sans utilisation d'hormones

International audienc

A bovine-specific FSH enzyme immunoassay and its application to study the role of FSH in ovarian follicle development during the postnatal period

International audienceThe primary aim of this study was to develop a FSH enzyme immunoassay (EIA) for the bovine species. The newly developed EIA was validated for FSH determination in bovine plasma by comparison with an existing bovine FSH radioimmunoassay. The EIA detected bovine FSH with a high sensitivity (0.1 ng/ml). Cross-reactivity of the EIA was 0.01% with bovine LH, 51% with ovine FSH, <0.1% with porcine FSH and <0.01% with equine FSH. Using this EIA on different time series of plasma in cows, we have confirmed the presence of a FSH pre-ovulatory peak at estrus, of periodic FSH fluctuations accompanying the waves of terminal follicular development, and of FSH pulses, mainly asynchronous with LH ones, in the peri-ovulatory phase of the cycle. In a second objective, the EIA was used to assess the role of FSH in regulating the development of ovarian follicles up to the small antral stage in young calves. To answer this question, six calves were submitted to weekly blood sampling during their first 3 months of life, and FSH changes were studied concomitantly to those of anti-Mullerian hormone (AMH), a well-established endocrine marker of the ovarian population of small antral follicles in cows. In the ovaries of 3-month calves, the population of 3 to 5 mm follicles contained the highest intra-follicular AMH amounts, and the number of 3 to 5 mm follicles on ovaries was closely correlated with AMH concentrations in the plasma of calves at this age (r(s) = 0.94). Before 3 months of age, only two out of six calves showed a clear postnatal FSH peak in plasma, and no correlation was found between plasma FSH and AMH concentrations. These results indicate that female calves undergo different patterns of FSH secretion and that postnatal activation of follicular growth up to the small antral stage appears independent and not directly related to circulating FSH levels

Comment les pratiques du quotidien peuvent améliorer le bien-être du cheval - une étude sur le brossage

Comment les pratiques du quotidien peuvent améliorer le bien-être du cheval - une étude sur le brossage. 47. Colloque Annuel de la Société Française pour l’Etude du Comportement Anima

Validation d'une méthode immunoenzymatique pour le dosage de la progestérone dans le plasma des ovins et des bovins

National audienc

Une alternance de 6 mois de jours longs et de jours naturels permet de réussir l’effet bouc en été sans mélatonine

International audienc

Reproductive parameters of donkey jacks undergoing puberty

International audienceIn male donkeys, puberty and the related events have been poorly characterized. The aim of this study was to evaluate the age at which male donkeys reach puberty, and characterize age associated changes in testicular size, testicular blood flow, serum testosterone concentration and semen quality. Every two months, starting at 6 months and finishing at 24 months of age, five male donkeys born in May to July were subjected to B-mode ultrasound examination to assess testicular size and scrotum content and blood serum sampling for testosterone concentration. From the age of 8 months, pulsed Doppler was employed to evaluate blood flow in the testicular artery. Testosterone serum concentration was evaluated via RIA. From the age of 12 months, monthly semen collections were attempted and semen was evaluated for sperm number, motility and morphology. Onset of puberty was defined as the first ejaculate containing >= 50 x 10(6) spermatozoa with >= 10% total motility. One of the donkeys was excluded from the statistical analyses due to a hydrocele presented during the study. Testes width was affected by age (P = 0.8 ng/ml). Spermatozoa appeared in the ejaculate at a mean age of 18.7 months and puberty was attained between 19 and 20 months of age (mean: 19.5 months), between January and February. In conclusion, late spring born Amiata donkey colts reached puberty at 19-20 months of age. Puberty was accompanied by changes in testicular size, testicular blood flow and serum testosterone concentration

Physiological changes in the peri-partum period and colostral IgG transfer in prolific D’man sheep: effects of parity and litter size

The aim of this work was to assess maternal and neonatal changes in plasma proteins, glucose and cortisol and to quantify the colostral immunoglobulin G (IgG) transfer in the peri-partum period in D'man sheep, a prolific breed, taking into account the parity of the ewe. The concentrations of proteins and glucose were high in the ewes on day 7 and at lambing before decreasing. Likewise, cortisol plasma concentration was maximal during the 6 h following lambing and dropped at 12 h. Protein and glucose concentrations were low in lambs at 1 h of birth after which they increased. By contrast, cortisol level was the highest during the first 12 h of birth and then decreased. The colostral IgG level was high at lambing and dropped by over 87 % from 1 to 48 h post-partum. In the newborn, the plasma IgG concentration was lowest at birth and increased rapidly during the first 24 h of birth. Parity influenced maternal physiology with multiparous ewes having the lowest concentrations of proteins, glucose, IgG and cortisol, but the highest colostrum IgG level. Accordingly, lambs born from primiparous ewes had lower protein, glucose and plasma IgG concentrations than lambs born from multiparous ewes. The main outcome of this study was that lambs born from primiparous ewes are characterized by the lowest physiological indices and this may influence their survival chance