Early detection of anomalies is an important issue in the management of group-housed livestock. In particular, failure to detect oestrus in a timely and accurate way can become a limiting factor in achieving efficient reproductive performance. Although a rich variety of methods has been introduced for the detection of oestrus, a more accurate and practical method is still required. In this pape...

The chemical profiles of vaginal fluid collected from cows in oestrus and nonoestrus were analysed by gas chromatography-mass spectrometry (GC-MS) to establish any qualitative differences that might have potential value in bovine biocommunication. Eight different organic compounds were detected using the two chromatograms. The chemical profiles of oestrus vaginal fluid were distinguished signif...

Treatment of female mice with bromocriptine on Day 1 or 3 of pregnancy induced many of the females to return to oestrus. The incidence of extended cycles (7--10 days) and pseudopregnancies following this return to oestrus was significantly higher than in unmated control females. These observations are consistent with the existence of a 'mnemonic' component of the luteotrophic system in the mouse.

The objective of the present study was to determine whether oestrous detection with the help of oestrous detection aids during the Heatsynch without timed AI protocol is equally effective with the progesterone-combined protocol in dairy heifers. A total of 148 heifers were randomly assigned to one of the two groups. A group of heifers treated with Heatsynch with heat detection aids (n = 72) rec...

Control of oestrus in dog and cat can be divided into 2 parts, contraception and induction of oestrus and ovulation. For contraception, either dog or cat is operated by hormonal applications in the same way. Progestins have been used for a long time to postpone estrus with their major side effects. Nowadays, other hormonal remedies become more accepted such as a long term implants of GnRH agoni...

Lactation delays the re-initiation of oestrous cyclicity in rats, resulting in physiological sterility for the duration of suckling. During this phase, the secretion of pituitary gonadotrophins is suppressed by an unknown mechanism. Continued application of the suckling stimulus by litter replacement (Bruce, 1958; Nicoll & Meites, 1959), or injections of prolactin (Meites & Nicoll, 1959), have ...

Ewes in which oestrus had been synchronised were artificially inseminated (at the second synchronised oestrus) 17 to 21 days after placement on plots containing either oestrogenic (Trifolium subterraneum L. c% Dinninup) or non oestrogenic pasture. A comparison of the reproductive performance indicated that grazing oestrogenic pasture prior to and during joining reduced the proportion of ewes in...