| Records |
| Author |
Khalil, A.M.; Murakami, N.; Kaseda, Y. |
| Title |
Relationship between plasma testosterone concentrations and age, breeding season and harem size in Misaki feral horses |
Type |
Journal Article |
| Year |
1998 |
Publication |
The Journal of veterinary medical science / the Japanese Society of Veterinary Science |
Abbreviated Journal |
J Vet Med Sci |
| Volume |
60 |
Issue |
5 |
Pages |
643-645 |
| Keywords |
Age Factors; Animals; Animals, Wild; *Horses; Japan; Male; Reproduction; Seasons; Sexual Behavior, Animal; Sexual Maturation; *Social Behavior; Testosterone/*blood |
| Abstract |
Jugular vein blood samples were collected from 23 young and sexual mature feral stallions to examine the relationship between plasma testosterone concentration and age, breeding season or harem size. Testosterone concentration increased with the age of the stallions until they formed their own harems, at about 4 to 6 years old. Seasonal variations in testosterone concentrations were observed, and found to be significantly higher (P<0.001) throughout the breeding season than non-breeding season, from 3 years of age. Testosterone levels were correlated with harem size for individual stallions. It can be inferred from these results that there is a relationship between plasma testosterone concentration and age, breeding season and harem size. |
| Address |
Laboratory of Animal Behavioral Science, Faculty of Agriculture, Miyazaki University, Japan |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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ISSN  |
0916-7250 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:9637303 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
137 |
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| Author |
Villani, M.; Cairoli, F.; Kindahl, H.; Galeati, G.; Faustini, M.; Carluccio, A.; Veronesi, M.C. |
| Title |
Effects of mating on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF2alpha in stallions |
Type |
Journal Article |
| Year |
2006 |
Publication |
Reproduction in Domestic Animals = Zuchthygiene |
Abbreviated Journal |
Reprod Domest Anim |
| Volume |
41 |
Issue |
6 |
Pages |
544-548 |
| Keywords |
Animals; Dinoprost/*analogs & derivatives/blood; Ejaculation/physiology; Estrone/*analogs & derivatives/blood; Horses/*blood/physiology; Hydrocortisone/*blood; Male; Sexual Behavior, Animal/*physiology; Testosterone/*blood |
| Abstract |
Very little information is available regarding the physiological mechanisms involved in the normal sexual activity in the stallion and, in particular, the endocrine control of reproduction is still not clearly understood. This experiment was designed to determine the short-term effect of sexual stimulation on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF(2alpha) in stallions. Semen samples were collected from 10 lighthorse stallions of proven fertility using a Missouri model artificial vagina. At the same time, blood samples were collected from the jugular vein with heparinized tubes, 20 and 10 min before oestrous mare exposure, at exposure and 10, 20, 30 min after dismounting. Testosterone concentrations showed a sharp rise 10 min after mating (p < 0.001), reached a plateau, and then showed a further increase 30 min after mating (p < 0.001). Cortisol concentrations increased 10 min after mating (p < 0.001) and remained at high levels in the subsequent samples taken. A peak of oestrone sulphate was observed 10 min after mating (p < 0.001). 15-Ketodihydro-PGF(2alpha) concentrations decreased rapidly at the moment of the exposure of the stallions to an oestrous mare (p < 0.05), returned to pre-mating concentrations and then decreased again 30 min after mating (p < 0.05). |
| Address |
Dipartimento di Scienze Cliniche Veterinarie, Sez. Clinica Ostetrica e Ginecologica Veterinaria, Milan, Italy |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0936-6768 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:17107515 |
Approved |
no |
| Call Number |
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Serial |
1855 |
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| Author |
Malmgren, L.; Andresen, Ø.; Dalin, A.-M. |
| Title |
Effect of GnRH immunisation on hormonal levels, sexual behaviour, semen quality and testicular morphology in mature stallions |
Type |
Journal Article |
| Year |
2001 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine vet. J. |
| Volume |
33 |
Issue |
1 |
Pages |
75-83 |
| Keywords |
horse; GnRH; immunisation; stallion; testosterone; oestrone sulphate; sexual behaviour; semen quality |
| Abstract |
Summary The aim of this study was to investigate the effect of gonadotrophin-releasing hormone (GnRH) immunisation on mature stallions that had been used for breeding. Four Standardbred stallions were used in the study: 3 experimental animals and 1 control animal. Semen was collected regularly, i.e. twice/week, during the 4 months prior to the experimental period. The stallions were immunised against GnRH with a GnRH-BSA conjugate. Equimune was used as the adjuvant. The stallions were immunised on 5 occasions, 4 at 2 week intervals, and the fifth 4 weeks after the fourth. Blood samples were taken once a week for analysis of GnRH antibody titre and every third week for testosterone and oestrone sulphate analyses. Semen was collected once a week, and libido and sexual behaviour were observed. Ejaculate volume, sperm concentration, total number of sperm in the ejaculate, sperm motility and sperm morphology were evaluated. Testicular size was measured once a week. At the end of the study, the stallions were castrated, and a histological examination of the testes performed. All immunised stallions produced antibodies against GnRH, and plasma testosterone concentration decreased. However, the effect of immunisation varied between stallions. In 2 of the stallions, high levels of antibodies were found, while in the third, the level was moderate. Four weeks after the first immunisation, a decrease in libido was observed. Two months after the first immunisation, marked changes in semen quality were observed in the 2 stallions with high antibody titres. Fourteen weeks after the first immunisation, the total number of sperm/ejaculate had decreased from >8.6×109 to<2.7×109, sperm motility from >59 to<10% and the frequency of morphological normal spermatozoa had decreased from >60 to<14%. The dominating abnormalities were abnormal head shapes, proximal cytoplasmic droplets and detached heads. In the third stallion, only slight changes in semen quality were found. No changes were observed in the control stallion. Decreases in testicular size were noted in all of the experimental stallions. Pronounced histological alterations in the testes were observed in 2 of the stallions. It is concluded that the vaccine was effective in stimulating production of GnRH antibodies and in suppressing testicular function and androgen secretion. However, there was an individual variation in the responses among the stallions and, further, libido was not totally suppressed. |
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| Publisher |
Blackwell Publishing Ltd |
Place of Publication |
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Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2042-3306 |
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Expedition |
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| Notes |
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Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5312 |
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