Skip to main content Accessibility help
×
Home

Photoperiodic control of breeding activity in the Southdown ewe with particular reference to the effects of an equatorial light regime

  • C. J. Thwaites (a1)

Extract

1. Oestrous activity was studied in three groups of eight Southdown ewes exposed respectively to natural lighting (30½° S.), accentuated reversed seasonal lighting, and equatorial lighting for a period of 2 years.

2. Control ewes exhibited a restricted breeding season confined to the autumn and winter months of each year. The breeding season averaged 102–5 days in length and during it the ewes experienced an average of 7·14 ± 0·47 oestrous periods.

3. The natural breeding season was almost completely reversed by artificial reversal of the normal seasonal variation in daylength. This constitutes presumptive evidence that daylength is the major factor controlling seasonality of oestrus in Southdown ewes.

Copyright

References

Hide All
Amoroso, E. C. & Marshall, F. H. A. (1960). Chapter 13 in Marshall's Physiology of Reproduction (ed. Parkes, A. S.) vol. I, pt. 2. London: Longmans Green.
Bonsma, J. C. & Pretorius, A. J. (1943). Fmg. in S. Afr. 18, 101.
Bullough, W. S. (1951). Vertebrate Sexual Cycles. London: Methuen.
Cole, H. H. (1953). Iowa St. Coll. J. Sci. 28, 133.
Debaca, R. C, Warnick, A. C, Hitchcock, G. H. & Bogart, R. (1954). Ore. Agric. Exp. Sta. Tech. Bull. no. 29.
Dutt, R. H. (1960). J. Dairy Sci. 43, 123.
Dutt, R. H. & Bush, L. F. (1955). J. Anim. Sci. 14, 885.
Hafez, E. S. E. (1952a). J. Agric. Sci. 42, 189.
Hafez, E. S. E. (1952b). J. Agric. Sci. 42, 199.
Hafez, E. S. E. (1952c). J. Agric. Sci. 42, 232.
Hammond, J. jun, (1944). J. Agric. Sci. 34, 97.
Hart, D. S. (1950). J. Agric. Sci. 40, 143.
Kelley, R. B. & Shaw, H. E. B. (1943). Counc. Sci. Ind. Res., Aust. Bull., no. 166.
Larionov, W. T. (1941). Dokl. Akad. Nauk, SSSR, N.S. 30, 374. (A.B.A. 11, 125.)
Marshall, F. H. A. (1942). Biol. Rev. 17, 68.
Radford, H. M. (1961a). Aust. J. Agric. Res. 12, 139.
Radford, H. M. (1961b). Aust. J. Agric. Res. 12, 147.
Radford, H. M. & Watson, R. H. (1957). Aust. J. Agric. Res. 8, 460.
Radford, H. M., Watson, R. H. & Wood, G. F. (1960). Aust. Vet. J. 36, 57.
Watson, R. H. & Radford, H. M. (1955). Aust. Vet. J. 31, 31.
Yeates, N. T. M. (1949). J. Agric. Sci. 39, 1.
Yeates, N. T. M. (1956a). Aust. J. Agric. Res. 7, 440.
Yeates, N. T. M. (1956b). Man and Animals in the Tropics, p. 97. Proc. Aust. Aoad. Sci. Symp., brisbane.
Yeates, N. T. M. (1965). Modern Aspects of Animal Production. London: Butterworths. (In the Press.)

Photoperiodic control of breeding activity in the Southdown ewe with particular reference to the effects of an equatorial light regime

  • C. J. Thwaites (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed