EurekaMag.com logo
+ Site Statistics
References:
53,869,633
Abstracts:
29,686,251
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on LinkedInFollow on LinkedIn

+ Translate

The effect of rearing under a long or short photoperiod on testis growth, plasma testosterone and prolactin concentrations, and the development of sexual behaviour in rams



The effect of rearing under a long or short photoperiod on testis growth, plasma testosterone and prolactin concentrations, and the development of sexual behaviour in rams



Journal of Reproduction and Fertility 60(2): 437-447



Two groups of 6 rams were maintained under constant photoperiodic conditions consisting of short days (8 h light: 16 h dark; Group S) and long days (16 h light; 8 h dark; Group L) from 4-20 mo. of age. Other rams (5) were reared under a photoperiod representative of that occurring-naturally (Group N). Testis size, plasma testosterone [T] and prolactin [PRL] concentrations were monitored weekly and sexual behavior tests were carried out at regular intervals. Over the treatment period Groups S and L did not differ in terms of testis growth or plasma T. Both groups had a phase of testis growth and increased T followed by a decline and the temporal patterns for the 2 groups were equivalent. Sexual behavior was slower to develop in Group L than in Group S, indicating that photoperiod can affect the sexual behavior development irrespective of peripheral plasma T concentrations. Plasma PL levels showed a cyclic variation in Group L and were significantly higher overall than in Group S rams. This, together with a trend towards negative correlations between PRL concentrations and sexual behavior in Group L, indicates that PRL may be involved in the photoperiod effect on sexual behavior. The presence of a cycle of testicular growth and of hormone concentrations in young animals under constant photoperiod tentatively suggests that these cycles are endogenous. The constant photoperiod did affect the animals because the cycles which occurred in Groups S and L were out of phase with those of Group N by about 4 mo.

(PDF emailed within 0-6 h: $19.90)

Accession: 001006061

Download citation: RISBibTeXText

PMID: 7431348

DOI: 10.1530/jrf.0.0600437



Related references

The absence of any effect of constant long or short photoperiod on growth, sexual development and behaviour of male lambs from birth to 9 months of age. Animal Science (Pencaitland) 62(3): 667, 1996

Reproductive Development of Santa In s Rams During the First Year of Life Body and Testis Growth, Testosterone Concentrations, Sperm Parameters, Age at Puberty and Seminal Plasma Proteins. 2009

Reproductive development of Santa InĂªs rams during the first year of life: body and testis growth, testosterone concentrations, sperm parameters, age at puberty and seminal plasma proteins. Reproduction in Domestic Animals 45(4): 644-653, 2011

Long-term rhythms of testicular volume and plasma prolactin concentrations in rams reared for 3 years in constant photoperiod. Journal of Reproduction and Fertility 65(2): 439-446, 1982

Effect of pinealectomy on the plasma concentrations of prolactin, cortisol and testosterone in sheep in short and skeleton long photoperiods. Journal of Endocrinology 100(3): 287-294, 1984

Photoperiod entrainment of testosterone luteinizing hormone fsh and prolactin cycles in rams in relation to testis size and semen quality. Biology of Reproduction 37(2): 489-499, 1987

Serum prolactin and testosterone concentrations are not altered by sexual behavior in mature rams. Journal of Animal Science 73(SUPPL 1): 129, 1995

Photoperiod entrainment of testosterone, luteinizing hormone, follicle- stimulating hormone, and prolactin cycles in rams in relation to testis size and semen quality. Biology of Reproduction 37(2): 489-499, 1987

Photoperiod entrainment of testosterone, luteinizing hormone, follicle-stimulating hormone, and prolactin cycles in rams in relation to testis size and semen quality. Biology of Reproduction 37(2): 489-499, 1987

Effect of mouse epidermal growth factor on plasma concentrations of LH, FSH and testosterone in rams. Journal of Reproduction and Fertility 87(2): 649-655, 1989

The relationships between body weight, testis size and blood LH, testosterone and prolactin concentrations in the first year of life in Polish Longwool rams kept in natural or artifical light. Advances in Agricultural Sciences 2(1): 3-10, 1993

Changes in melatonin concentrations in seminal plasma are not correlated with testosterone or antioxidant enzyme activity when rams are located in areas with an equatorial photoperiod. Animal Reproduction Science 200: 22-30, 2018

The relationship between testis size and stimulated plasma testosterone concentrations and its influence on mating performance in dorper rams. South African Journal of Animal Science 17(2): 63-69, 1987

Induction of testicular growth and sexual activity in rams by a 'skeleton' short-day photoperiod. Journal of Reproduction and Fertility 52(1): 179-181, 1978

Effects of recent sexual experience and melatonin treatment of rams on plasma testosterone concentration, sexual behaviour and ability to induce ovulation in seasonally anoestrous ewes. Journal of Reproduction and Fertility 120(1): 169-176, 2000