Seasonal cyclic pituitary and testicular activities in rams

Small Ruminant Research

Volumn 33, Issue 1, 1999, Pages 43-53

  Langford, G A ^a   Sanford, L M ^b   Marcus, G J ^a   Shrestha, J N B ^a  

^a AGRICULTURE AND AGRI FOOD CANADA   (Canada)

^b MCGILL UNIVERSITY   (Canada)

Author keywords

Arcott breeds; Endogenous cycles; Photoperiod; Rams; Testicular function

Indexed keywords

EID: 0032970926     PISSN: 09214488     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0921-4488(98)00199-0     Document Type: Article

References (36)

1. Almeida O.F.X., Lincoln G.A. Photoperiodic regulation of reproductive activity in the ram: evidence for the involvement of circadian rhythms in melatonin and prolactin secretion. Biol. Reprod. 27:1982;1062-1075.
2. Almeida O.F.X., Lincoln G.A. Reproductive photorefractoriness in rams and accompanying changes in the pattern of melatonin and prolactin secretion. Biol. Reprod. 30:1984;143-158.
3. Arendt J. Role of the pineal gland and melatonin in seasonal reproductive function in mammals. Oxford Rev. Reprod. Biol. 8:1986;266-320.
4. Bronson, F.H., Heideman, P.D., 1994. Seasonal regulation of reproduction in mammals. In: Knobil, E., Neill, J.D. (Eds.), The Physiology of Reproduction, vol. 2, 2nd ed., Raven Press, New York, pp. 541-583.
5. Cameron, A.W.N., Fairnie, I.J., Curnow, D.H., Keogh, E.J., Lindsay, D.R., 1984. The output of spermatozoa of naturally mated rams. Proc. 10th Int. Congr. Anim. Reprod. and A.I., Urbana-Champaign, Illinois, vol. 2, p. 266.
6. Cheng K.W., Simaraks S., Palmer W.M. Characterization of a radioimmunoassay for ovine FSH utilizing an antibovine FSH serum. J. Reprod. Fertil. 61:1981;115-121.
7. D'Occhio M.J., Schanbacher B.D., Kinder J.E. Profiles of luteinizing hormone, follicle stimulating hormone, testosterone and prolactin in rams of diverse breeds: Effects of contrasting short (8L : 16D) and long (16L : 8D) photoperiods. Biol. Reprod. 30:1984;1039-1054.
8. Ducker, M.J., Bowman, J.C., Temple, A., 1973. The effect of constant photoperiod on the expression of oestrus in the ewe. J. Reprod. Fertil. 19 (Suppl.), 143-150.
9. Duncan D.B. Multiple range and multiple F-tests. Biometrics. 11:1955;1-42.
10. Foldes A., Maxwell C.A., Carter N.B., Scaramuzzi R.J. Effect of prolonged artificial photoperiod on circulating prolactin and melatonin levels in seasonal ewes. Neurochem. Res. 16:1991;693-697.
11. Harvey, W.R., 1975. Least-squares analysis of data with unequal subclass numbers. USDA, ARS. H-4, Washington, DC, p. 157.
12. Howles C.M., Craigon J., Haynes N.B. Long term rhythms of testicular volume and plasma prolactin concentrations in rams reared for 3 years in constant photoperiod. J. Reprod. Fertil. 65:1982;439-446.
13. Howles C.M., Webster G.M., Haynes N.B. 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. J. Reprod. Fertil. 60:1980;437-447.
14. Jackson G.L., Jansen H., Kao C. Continuous exposure of Suffolk ewes to an equatorial photoperiod disrupts expression of the annual breeding season. Biol. Reprod. 42:1990;63-73.
15. Jallageas M., Mas N., Assenmacher I. Further demonstration of the ambient temperature dependence of the annual biological cycles in the edible dormouse Glis glis. J. Comp. Physio. B. 159:1989;333-338.
16. Karsch F.J., Robinson J.E., Woodfill C.J.I., Brown M.B. Circannual cycles of luteinizing hormone and prolactin secretion in ewes during prolonged exposure to a fixed photoperiod: Evidence for an endogenous reproductive rhythm. Biol. Reprod. 41:1989;1034-1046.
17. Kramer C.Y. Extension of multiple range tests for group correlated adjusted means. Biometrics. 13:1957;13-18.
18. Langford G.A., Shrestha J.N.B., Sanford L.M., Marcus G.J. Reproductive hormone levels of early postpubertal ram lambs in relation to breed, adult testes size and semen quality. Small Rumin. Res. 29:1998;225-232.
19. Langford G.A., Shrestha J.N.B., Marcus G.J. Repeatability of scrotal size and semen quality measurements in rams in a short day light regime. Anim. Reprod. Sci. 19:1989;19-27.
20. Langford G.A., Ainsworth L., Marcus G.J., Shrestha J.N.B. Photoperiod entrainment of testosterone, LH, FSH and prolactin cycles in rams in relation to testis size and semen quality. Biol. Reprod. 37:1987;489-499.
21. Lincoln, G.A., 1978. The photoperiodic control of seasonal breeding in rams. In: Gaillard, P.J., Boer, H.H. (Eds.), Comparative Endocrinology. Elsevier North-Holland Biomedical Press, Amsterdam, pp. 149-152.
22. Lincoln G.A. Photoperiodic control of seasonal breeding in the ram: participation of the cranial sympathetic nervous system. J. Endocrinol. 82:1979;135-147.
23. Lincoln G.A., Davidson W. The relationship between sexual and aggressive behaviour and pituitary and testicular activity during the seasonal sexual cycle of rams and the influence of photoperiod. J. Reprod. Fertil. 49:1977;267-276.
24. Lincoln G.A., Short R.V. Seasonal breeding: Nature's contraceptive. Recent Prog. Horm. Res. 36:1980;1-52.
25. Lincoln G.A., Libre E.A., Merriam G.R. Long-term reproductive cycles in rams after pinealectomy or superior cervical ganglionectomy. J. Reprod. Fertil. 85:1989;687-704.
26. Lincoln G.A., Almeida O.F.X., Klandorf H., Cunningham R.A. Hourly fluctuations in the blood levels of melatonin, prolactin, luteinizing hormone, follicle stimulating hormone, testosterone, tri-iodothyronine, thyroxine and cortisol in rams under availability photoperiods, and the effects of cranial sympathectomy. J. Endocrinol. 90:1982;237-250.
27. Lino B.F. The output of spermatozoa in rams II. Relationship to scrotal circumference, testis weight and the number of spermatozoa in different parts of the urogenital tract. Aust. J. Biol. Sci. 25:1972;359-366.
28. Marquardt M. An algorithm for least squares estimation of non-linear parameters. J. Soc. Ind. Appl. Math. 11:1963;431-441.
29. Pelletier, J., Almeida, G., 1987. Short light cycles induce persistent reproductive activity in Ile-de-France rams. J. Reprod. Fertil. 34 (Suppl.), 215-216.
30. Robinson J.E., Karsch F.J. Photoperiodic history and a changing melatonin pattern can determine the neuroendocrine response of the ewe to daylength. J. Reprod. Fertil. 80:1987;159-165.
31. Sanford L.M. Evidence that estrogen regulation of testosterone secretion in adult rams is mediated by both indirect (gonadotrophin-dependent) and direct (gonadotrophin-independent) means. J. Androl. 6:1985;306.
32. Sanford L.M., Beaton D.B., Howland B.E., Palmer W.M. Photoperiod-induced changes in LH, FSH, prolactin and testosterone secretion in the ram. Can. J. Anim. Sci. 45:1978;1382-1391.
33. Schanbacher B.D., D'Occhio M.J. Validation of direct radioimmunoassay for testosterone in unextracted serum from five species: Application to the study of hypothalamic-pituitary-gonadal axis in males. J. Androl. 3:1982;45-51.
34. Shrestha J.N.B., Heaney D.P. Genetic basis of variation in reproductive performance (2) Genetic correlations between gestation length and prolificacy in sheep. Anim. Reprod. Sci. 23:1990;305-317.
35. Shrestha, J.N.B., Hansen, C., 1998. Developing synthetic breeds of sheep: A review of the Canadian experience. Proc. 6th World Cong. on Genet. Appl. Livest. Prod. 24, 121-124.
36. Yeates N.T.M. The breeding season of the sheep with particular reference to its modification by artificial means using light. Agric. Sci. 39:1949;1-43.