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  1. Absence of effects from immunocontraception on seasonal birth patterns and foal survival among barrier island wild horses

    Contributor(s):: Kirkpatrick, J. F., Turner, A.

    Despite a large body of safety data, concern exists that porcine zonae pellucidae (PZP) immunocontraception - used to manage wild horse populations - may cause out-of-season births with resulting foal mortality. Our study at Assateague, Maryland indicated the effects of immunocontraception on...

  2. Assessment: effects of porcine zona pellucida immunocontraception on oestrous cyclicity in feral horses

    Contributor(s):: Powell, D. M., Monfort, S. L.

    The following study used noninvasive faecal hormone monitoring to assess whether contraception with porcine zona pellucida (PZP) had an impact on oestrous cycle characteristics in a herd of feral horses living on Assateague Island, Maryland. The study assayed longitudinal faecal samples,...

  3. Human-animal interaction, stress, and embryo production in Bos indicus embryo donors under tropical conditions

    Contributor(s):: Macedo, G. G., Zuccari Neto, C. E. S., Abreu, U. G. P. de, Negrao, J. A., Costa e Silva, E. V. da

    This study investigated the effect of human-animal interaction (HAI) and the stress response on the quality of embryo production in superovulated Nelore (Bos indicus) cattle, under tropical conditions. Thirty-two females underwent a superovulation protocol for 5 days. Cortisol concentrations were...

  4. A note on silent ovulation identified by using radiotelemetry for estrous detection

    Contributor(s):: Shipka, M. P.

    The occurrence of silent ovulation in high-producing, postpartum Holstein cows was examined. 19 multiparous cows were fitted with transmitters (HeatwatchReg.) for radiotelemetry and examined using a visual oestrus detection routine for 1/2 h twice daily, on day 10 post partum. Blood samples were...

  5. A note on the effect of continuous ram presence on estrus onset, estrus duration and ovulation time in estrus synchronized ewes

    Contributor(s):: Romano, J. E., Fernandez Abella, D., Villegas, N.

    During fall season, 18 multiparous Corriedale ewes were divided into two equal groups for the continuous (CON) and intermittent (INT) presence of a ram. Oestrus was synchronized with fluorgestone acetate intravaginal sponges (Chronogest) that were left 14 days, plus an injection of 200 micro g of...

  6. Further evaluation of the developmental asynchrony hypothesis of sex ratio variation

    Contributor(s):: Krackow, S.

    A discussion of differences in the speed of development of male and female blastocysts up to the stage of uterine implantation compared with the developmental stage of the uterus may cause sex ratio biases in response to environmental, physiological and psychological cues. It may also cause sub...

  7. The effect of exposure to oestrous ewes on rams' sexual behaviour, plasma testosterone concentration and ability to stimulate ovulation in seasonally anoestrous ewes

    Contributor(s):: Rosa, H. J. D., Juniper, D. T., Bryant, M. J.

    272 ewes were introduced to (1) rams without recent experience of oestrous ewes, (2) rams recently exposed to oestrous ewes, (3) and (4) oestrous ewes and rams with or without recent experience with oestrous ewes, or (5) remained isolated from rams. Serum testosterone concentration of rams was...

  8. The influence of adverse or gentle handling procedures on sexual behaviour in fearful and confident sows

    Contributor(s):: Pedersen, L. J., Damm, B. I., Kongsted, A. G.

    In the present study, the influence of handling during lactation on fear of humans and on sexual behaviour in the presence and absence of a human was investigated. Prior to handling, the sows were selected as being either fearful (n=24) or confident (n=24) towards humans based on their reactions...

  9. Artificial selection of rams for sexual performance and its effect on the sexual behavior and fecundity of male and female progeny

    Contributor(s):: Bench, C. J., Price, E. O., Dally, M. R., Borgwardt, R. E.

    The objective of this study was to determine the effect of a single generation of artificial selection for sexual performance in rams on the sexual behaviour and fecundity of their male and female progeny. Ninety-two ram lambs born to sires selected for either high or low sexual performance were...

  10. Physiological and behavioural responses of cows from two beef breeds submitted to different suckling strategies

    Contributor(s):: Alvarez-Rodriguez, J., Sanz, A.

    This experiment was designed to study the effects of avoiding calf contact and genotype on the metabolic, behavioural and reproductive traits of beef cows during lactation. Fifty-two multiparous cows, 25 Parda de Montana (PA) and 27 Pirenaica (PI), fed at maintenance were assigned from the day...

  11. Social dominance of female goats affects their response to the male effect

    Contributor(s):: Alvarez, L., Martin, G. B., Galindo, F., Zarco, L. A.

    The aim of this study was to assess the influence of social rank of anestrous goats on their interval to ovulation after exposure to males. Forty-five adult females were observed before and after the introduction of males to their pen. Behavioural sampling was used in both periods to record...

  12. Effectiveness of testosterone-treated wethers and ewes as teasers

    Contributor(s):: Signoret, J. P., Fulkerson, W. J., Lindsay, D. R.

    Two series of experiments were conducted using Merinos in Oct. 1979. In the 1st series of experiments using lactating ewes, 3 wk post partum, 8 of 46 and 17 of 47 ewes ovulated after 4 days of contact with 2 androgenised wethers selected for low libido and 6 wethers selected for high libido resp....

  13. Importance of behavioural stimuli in ram-induced ovulation in seasonally anovular Corriedale ewes

    Contributor(s):: Rodriguez Inglesias, R. M., Ciccioli, N. H., Irazoqui, H., Rodriguez, B. T.

    Three groups of about 65 seasonally anovular Corriedale ewes were penned and exposed to rams on 4 Nov. A 4th group (n = 64) was maintained in a 3-ha paddock and also exposed to rams on the same date. Sexual behaviour exhibited by rams in contact with penned ewes was recorded during 9 simultaneous...

  14. Social dominance of female dairy goats and response to oestrous synchronisation and superovulatory treatments

    Contributor(s):: Ungerfeld, R., Gonzalez-Pensado, S., Dago, A. L., Vilarino, M., Menchaca, A.

    Two experiments were performed to determine if there is a relation between the goat's hierarchical position, and (1) the conception rate and litter size obtained with hormonal oestrous synchronisation treatments and fixed timed artificial insemination, and (2) the number of corpus luteum (CL) and...

  15. A proposition for an updated behavioural characterization of the oestrus period in dairy cows

    Contributor(s):: Kerbrat, S., Disenhaus, C.

    In high-yielding dairy herds, the difficulty associated with successfully detecting oestrus is a problem that limits the reproductive performance of the herd. Traditionally, the period when the cow stands to be mounted is taken as the oestrus period. Housing and management factors such as the use...

  16. The effects of superovulation hormone treatments on the frequency of estrous behaviours in cows

    Contributor(s):: Jezierski, T.

    Superovulation was induced in 37 Polish Black-and-White Lowland dairy cows by injections of cloprostenol (a PGF2 alpha analogue) and FSH. 120 untreated herdmates were used as controls. The frequencies of mountings and vulva sniffings during a total of 275 oestrous cycles during which cows...