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 short and skeleton long photoperiods on the plasma concentrations of prolactin and cortisol in sheep



The effect of short and skeleton long photoperiods on the plasma concentrations of prolactin and cortisol in sheep



Reproduction, Nutrition, Developpement 24(2): 107-116



Suffolk-cross lambs aged 8 wk were exposed to either short photoperiods (8L:16D [L:D, h of light: h of dark] SP; 7 castrated males and 6 females) or skeleton long photoperiods (7L:10D:1L:6D, SLP; 6 castrated males and 7 females). They were fed individually on a complete pelleted diet at 70 g/kg live weight 0.75/day. Blood samples were taken monthly by jugular puncture for 3 mo. and, after 39 days on experiment, jugular catheters were inserted for frequent sampling over 24 h. The samples were assayed for prolactin using radioimmunoassay and for cortisol by competitive protein binding. SLP caused a large and significant increase in plasma prolactin throughout the experiment, with no effect of sex. During the 24 h period there were consistent peaks of prolactin at the start of both dark phases under SLP, with lower levels around the start of both light phases; under SP, prolactin tended to be higher in the middle of the light phase and the middle of the dark phase than at other times. Considerably hourly fluctuations were observed in cortisol levels but an obvious 24 h rhythm was not. Mean levels were significantly higher under SP (38.3 nmol/l) than under SLP (26.8 nmol/l). [Effects on growth and seasonal reproductive cycles are implicated.].

(PDF emailed within 1 workday: $29.90)

Accession: 006654143

Download citation: RISBibTeXText

PMID: 6709959



Related references

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

Melatonin in the plasma of growing sheep subjected to short and skeleton long photoperiods. Experientia 40(7): 758-760, 1984

The effect of different photoperiods on plasma concentrations of melatonin, prolactin, and cortisol in the domestic cat. Endocrinology 115(5): 1729-1736, 1984

Plasma prolactin concentrations in the fetal sheep normal concentrations before delivery and the effect of cortisol induced delivery. Journal of Endocrinology 72(1): 36P-37P, 1977

Plasma prolactin concentrations in the foetal sheep: normal concentrations before delivery and the effect of cortisol induced delivery. Journal of endocrinology: 72 (1) 36P-37P, 1977

Daily changes in concentrations of prolactin in serum of prepubertal bulls exposed to short- or long-day photoperiods. Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine 191(1): 37-42, 1989

Effects of chronic lameness on the concentrations of cortisol, prolactin and vasopressin in the plasma of sheep. Veterinary Record 129(3): 45-47, 1991

Daily rhythm of cortisol, and evidence for a photo-inducible phase for prolactin secretion in nonpregnant mares housed under non-interrupted and skeleton photoperiods. Journal of Animal Science 63(1): 169-175, 1986

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, 1980

Diurnal variations in plasma concentrations of cortisol, prolactin, growth hormone and glucose in the fetal sheep and pregnant ewe during late gestation. Journal of Endocrinology 114(1): 65-72, 1987

Effect of acth on milk and plasma cortisol and prolactin concentrations. Journal of Dairy Science 64(9): 1794-1803, 1981

Effect of adrenocorticotropin on milk and plasma cortisol and prolactin concentrations. Journal of Dairy Science 64(9): 1794-1803, 1981