Effects of ewe proximity on peripheral plasma testosterone levels and behaviour in the ram

Illius, A. W.; Haynes, N. B.; Ge, Lan

doi:10.1530/jrf.0.0480025

Cited by 71 publications

(21 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A peak in testicular activity occurred at the end of 4 months of short days and the peak of aggressive behav iour was observed 1 month later. Also in adult rams, the proximity of females in heat affects the blood level of testosterone and an increase in this level is accompanied by an increase of aggressiveness [Illius et al, 1976], Sexual arousal, copulation or the simple proximity of a female causes a transitory rise of LH and testosterone in the bull [Katongole et al, 1971],…”

Section: Seasonal Variations In Agonistic and Related Behaviour As Rementioning

confidence: 99%

“…The authors interpret this relationship as a consequence and not a cause of their status since it has been well established that the sexual activity or the proximity of females may affect the levels of testosterone [Bramley and Neaves, 1972], Thus, the separation of male ungulates into 'territorial' (or possessors of harems) having access to reproduction, and 'bache lors' may be reinforced through testosterone levels associated with the age and the social environment. If the proximity to females and the possibility of copulation increase the level of testosterone, which in turn increases the aggressiveness, then dominant males will be more able to maintain their position [Illius et al, 1976].…”

Section: Seasonal Variations In Agonistic and Related Behaviour As Rementioning

confidence: 99%

See 1 more Smart Citation

Androgens, Aggressive Behaviour and Social Relationships in Higher Mammals

Bouissou¹

1983

Horm Res

102

View full text Add to dashboard Cite

This paper reviews the relationships between androgen levels, aggressive behaviour and social relationships in ungulates and primates. In these and most other mammalian species, aggressive behaviour is sexually dimorphic with males being generally more aggressive than females. This difference is evident very early in play behaviour. In males, and sometimes also in females, aggressive behaviour varies in relation with reproductive cycles and the hormonal changes which are involved in these cycles. The experimental manipulation of hormonal levels by castration or administration of exogenous hormones gives results that vary according to the species, sex, type of hormone (e.g. aromatizable or non-aromatizable androgens), and other factors (e.g. antlers state in stags). Nevertheless, it has generally been shown that aggressive behaviour in male ungulates depends largely on androgens and that in female ungulates androgen treatment consistently raises social rank, with or without modification in aggressiveness. Primates, on the other hand, seem to be less dependent on androgens for the expression of aggressive behaviour and social status.

show abstract

Section: Seasonal Variations In Agonistic and Related Behaviour As Rementioning

confidence: 99%

Section: Seasonal Variations In Agonistic and Related Behaviour As Rementioning

confidence: 99%

Androgens, Aggressive Behaviour and Social Relationships in Higher Mammals

Bouissou¹

1983

Horm Res

102

View full text Add to dashboard Cite

show abstract

“…Sanford et al (1974a) reported a similar increase in testosterone levels in two mature Finnish Landrace rams during a period of natural mating, whereas Purvis, Illius & Haynes ( 1974) reported that testosterone secretion was not affected by copulation. However, Illius, Haynes & Lamming (1976) subsequently found increases in plasma testosterone after copulation in some rams which had previously been kept in close proximity to ewes, but D'Occhio & Brooks (1976) reported that the plasma testosterone level of rams was not influenced by contact with oestrous ewes and was not correlated with the ram's performance in a standard libido test. The 'high versus low fertility ram stimulated versus unstimulated period' interaction was not significant, which suggests that the period of sexual stimulation did not improve the ability to detect differences in hormone concentration between high-and low-fertility rams.…”

Section: Resultsmentioning

confidence: 99%

Effects of sexual stimulation on plasma levels of LH and testosterone in rams from high- and low-fertility flocks

Moore¹,

Whyman²,

Wilson³

1978

Reproduction

View full text Add to dashboard Cite

Plasma LH and testosterone levels did not differ significantly between high and low fertility rams before or after sexual stimulation (ejaculation or teasing). Repeated stimulation caused significant elevation of mean plasma LH and an almost significant rise in testosterone concentration. Plasma testosterone peaks followed those of LH after 30-60 min. A single sexual stimulation did not always cause an LH peak or increase the mean LH level.

show abstract

“…Anticipated copulation or the presence of oestrous females is known to result in a rise in plasma testosterone (Katongole et al 1971, Jainudeen et al 1972, Kamel et al 1975, Illius et al 1976, and the presence of unfamiliar, more sexually attractive or more promiscuous female fowl (Gallus gallus) results in an increased number of ejaculated spermatozoa (Pizzari et al 2003). Changes in semen quality in the tammar may therefore reflect the number of available oestrous females, the level of inter-male competition, or both.…”

Section: Discussionmentioning

confidence: 99%

Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

Paris¹,

Taggart²,

Shaw³

et al. 2005

Reproduction

View full text Add to dashboard Cite

Changes in semen quality and morphology of the male reproductive tract were studied throughout the year in the highly promiscuous tammar wallaby. Body size, semen quality and gross morphology of the reproductive organs were assessed in adult males each month from January to November. The mean weight of males was similar in most periods sampled, but males were slightly heavier in the minor (P < 0.05) than the non-breeding season. Since body weight was correlated with weights of the testes, epididymides and accessory sex glands, organ weights were adjusted for body weight in subsequent analyses. In the major breeding season (late January/early February), when most females go through a brief, highly synchronized oestrus, the testes, prostate, Cowper's glands, crus penis and urethral bulb were heaviest, volume and coagulation of ejaculates were greatest, and sperm motility had increased. Semen samples collected by electroejaculation at this time contained low numbers of spermatozoa, possibly as a result of dilution and entrapment by the seminal coagulum or depletion of epididymal stores during intense multiple mating activity. In the non-breeding season (late May -July), when mating does not normally occur in the wild, there was a significant decrease in the relative weight of nearly all male reproductive organs and a decline in most semen parameters. In the minor breeding season (September -November), when pubertal females undergo their first oestrus and mating, the weights of testes, epididymides and most accessory sex glands had significantly increased similar to those of males in the major breeding season. The total number and motility of ejaculated spermatozoa were highest during this period, but the volume and coagulation of ejaculates and weight of the prostate had only increased to levels that were intermediate between the major and non-breeding seasons. Ejaculate volume was strongly correlated with prostate weight, and % motile spermatozoa was strongly correlated with epididymis weight. Semen quality thus varied seasonally with changes in androgendependent reproductive organs in the male tammar wallaby and appeared to be influenced by the seasonal timing of oestrus in females. Semen quality may also improve in response to an increase in the number of available oestrous females.

show abstract

Effects of ewe proximity on peripheral plasma testosterone levels and behaviour in the ram

Cited by 71 publications

References 18 publications

Androgens, Aggressive Behaviour and Social Relationships in Higher Mammals

Androgens, Aggressive Behaviour and Social Relationships in Higher Mammals

Effects of sexual stimulation on plasma levels of LH and testosterone in rams from high- and low-fertility flocks

Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female

Contact Info

Product

Resources

About