A stallion testicular cell incubation system was developed and used to investigate the regulation of steroidogenesis in stallion testes. Cells isolated from testes of 2- to 4-year-old stallions (n = 6) were cultured for 12 hours in a defined medium with and without varying doses of lipoprotein, equine luteinizing hormone (eLH), human chorionic gonadotropin (hCG), equine follicle-stimulating hor...

In oocytes from all mammalian species studied to date, fertilization by a spermatozoon induces intracellular calcium ([Ca(2+)](i)) oscillations that are crucial for appropriate oocyte activation and embryonic development. Such patterns are species-specific and have not yet been elucidated in horses; it is also not known whether equine oocytes respond with transient [Ca(2+)](i) oscillations when...

The primary aim of this study was to establish a flow cytometric technique for determining the capacitation status of stallion spermatozoa. To this end, a flow cytometric technique that demonstrates changes in plasma membrane fluidity; namely, merocyanine 540 staining, was compared with the more conventional Ca(2+)-dependent fluorescence microscopic technique, chlortetracycline (CTC) staining, ...

The aim of the project was to use current simple and practical laboratory tests and compare results with the foaling rates of mares inseminated with commercially produced frozen semen. In Exp. 1, semen was tested from 27 and in Exp. 2 from 23 stallions; 19 stallions participated in both experiments. The mean number of mares per stallion in both experiments was 37 (min. 7, max. 121). Sperm morph...

BACKGROUND Pseudomonas aeruginosa may cause venereal disease and infertility in horses. A Pseudomonas aeruginosa - carrier stallion, often unresponsive to artificial vagina collection, was used to naturally breed mares. Semen collected from the same stallion was also used to perform artificial inseminations. Pregnancy rates, embryo quality and incidence of uterine infection were compared betwee...

In the stallion testis, aromatase activity was localized in the microsomal fraction. Androgen aromatization occurred through the loss of 1 beta,2 beta hydrogen atoms and appeared to involve free sulfhydryl groups. A single enzyme system seemed to aromatize androgen and norandrogen at the same rate while having a much lower affinity for norandrogens.

the persian wild ass (equushemionusonager) has the smallest population among various wild ass subspecies and has only two isolated populations (500-600 individuals), that has been left in iran. therefore, captive breeding and re-introduction with post-release monitoring is considered a reliable conservation action. the present investigation illustrates efforts to re-introduce the onagers to its...

Sexual behavior problems in the stallion include several distinct types of dysfunction. Successful treatment, whether by tradit ional behavior modification or by pharmacological manipulation, usually depends on diagnosis of the specific dysfunctions involved. The following d’ lscussion of behavioral problems, evaluation, and therapy is organized according to the common types of sexual behavior ...