Hostname: page-component-8448b6f56d-xtgtn Total loading time: 0 Render date: 2024-04-19T22:44:01.829Z Has data issue: false hasContentIssue false
  • English
  • Français

Melatonin advances and condenses the onset of seasonal breeding in Greek dairy ewes

Published online by Cambridge University Press:  02 September 2010

S. A. Kouimtzis ,
Sofia Belibasaki  and
J. M. Doney
S. A. Kouimtzis
Affiliation:
Centre of Artificial Insemination and Pathology of Reproduction, Diavata, 570 08, Thessaloniki, Greece
Sofia Belibasaki
Affiliation:
Centre of Artificial Insemination and Pathology of Reproduction, Diavata, 570 08, Thessaloniki, Greece
J. M. Doney
Affiliation:
Centre of Artificial Insemination and Pathology of Reproduction, Diavata, 570 08, Thessaloniki, Greece
Get access

Abstract

The effects of melatonin, administered during anoestrus, on the time of onset of oestrus and on conception rate were investigated in two trials carried out on mature ewes of three indigenous and one imported breed. The ewes lambed between December and February, their lambs were weaned in March and they were hand milked twice daily until September.

In the first trial, 12 Chios and 12 Serres ewes were dosed, orally, for 60 days from 19 April with 3 mg melatonin (M) in 10 ml ethanol and water (1: 4 v/v). A similar number of Chios and Serres type ewes in the same flock were nominated as untreated controls (C). Vasectomized rams were used to detect oestrus from 1 May and detected ewes were immediately mated to entire rams of their own breed. The mean dates of first oestrus in Chios ewes were 4 July (s.e. 1·7 days) and 23 July (s.e. 5·4 days) (P < 0·01) for treated and control ewes respectively. Spread of first oestrus was 19 and 61 days, respectively (P < 0·01). Conception rate and ovulation rate were both higher in M (0·90 and 2·3, respectively) than in C (0·55 and 1·8, respectively) but the differences were not statistically significant. The corresponding results in the Serres ewes were 8 July (s.e. 1·6 days) and 31 July (s.e. 6·8 days) (P < 0·01) for date of first oestrus, 19 and 69 days (P < 0·01) for spread of first oestrus, 0·75 and 0·50 (P > 0·05) for conception rate and 1·8 and 1·2 ( P > 0·05) for ovulation rate.

In the second trial, 12 Karagouniko and 12 East Friesland ewes received a single subcutaneous implant of melatonin (Regulin®) on 5 June and a further 12 ewes of each breed were untreated controls. The procedure was as given for trial 1. The mean date of first oestrus was advanced by melatonin in both Karagouniko ewes (25 July (s.e. 3·91 days) v. 11 August (s.e. 6·7 days); P < 0·05) and Friesland ewes (28 July (s.e. 3·2 days) v. 24 August (s.e. 7·3 days); P < 0·01). Spread of oestrus was reduced (43 v. 68 days in Karagouniko, P < 0·05 and 22 v. 87 days in Friesland ewes, P < 0·01). Conception rate of melatonin-treated ewes was higher (0·60 v. 0·45; P > 0·05) in both breeds. Ovulation rate was higher in melatonin-treated Karagouniko ewes (1·8 v. 1·3; P > 0·05 but, in the Friesland breed melatonin-treated ewes had a lower ovulation rate (2·8 v. 3·7; P > 0·05).

In both trials, melatonin treatment significantly advanced and condensed the dates of first oestrus. Conception rate was consistently increased over all groups (P < 0·05) and there was a tendency towards a higher ovulation rate.

Type
Papers
Information
Animal Production , Volume 48 , Issue 2 , April 1989 , pp. 399 - 405
Copyright
Copyright © British Society of Animal Science 1989

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Arendt, J., Symons, A. M., Laud, C. A. and Pryde, S. J. 1983. Melatonin can induce the early onset of the breeding season in ewes. Journal of Endocrinology 97: 395–400.Google Scholar
English, J., Poulton, A. L., Arendt, J. and Symons, A. M. 1986. A comparison of the efficiency of melatonin treatments in advancing oestrus in ewes. Journal of Reproduction and Fertility 77: 321–327.Google Scholar
Haresign, W., Peters, A. R., Webster, G. M., King, J. W. B. and Staples, L. D. 1988. Effect of melatonin implants on reproductive performance in ewes. Animal Production 46: 498 (Abstr.).Google Scholar
Katsaounis, N. and Zygoyiannis, D. 1986. The East Friesland sheep in Greece. Research and Development in Agriculture 3: 19–30.Google Scholar
Kouimizis, S. A. 1985. The effect of litter size on lamb survival. In Factors Affecting the Survival of Newborn Lambs (ed. Alexander, G., Barker, J. D. and Slee, J.), pp 145–150. Seminar in the EEC Programme, Brussels.Google Scholar
Lincoln, G. A. 1983. Melatonin as a seasonal time-cue: a commercial story. Nature, London 302: 755.Google Scholar
Luhman, C. M. and Slyter, A. L. 1986. The effect of photoperiod and melatonin feeding on reproduction in the ewe. Theriogenology 26: 721–732.Google Scholar
Mason, I. L. 1967. Sheep Breeds of the Mediterranean. Commonwealth Agricultural Bureaux, Slough.Google Scholar
Nett, T. M. and Niswender, G. D. 1982. Influence of exogenous melatonin on seasonality of reproduction in sheep. Theriogenology 17: 645–653.CrossRefGoogle Scholar
Nowak, R. and Rodway, R. G. 1985. Effects of intravaginal implants of melatonin on the onset of ovarian activity in adult and prepubertal ewes. Journal of Reproduction and Fertility 74: 287–293.Google Scholar
Nowak, R. and Rodway, R. G. 1987. Length of melatonin exposure and onset of ovarian activity in anoestrous ewes. Journal of Reproduction and Fertility 80: 343–347.Google Scholar
Robinson, J. J., Aitken, R., Atkinson, T. and Fraser, C. 1985. The effects of oral administration of melatonin and/or exposure to a vasetomized ram on ovarian activity in ewes. Animal Production 40: 524 (Abstr.).Google Scholar
Rodway, A. G., Rajkumar, R. R., Nowak, R., Ward, S. J. and Argo, C. M. 1986. The use of vaginally administered melatonin in the manipulation of the breeding season in ewes. Animal Production 42: 448 (Abstr.).Google Scholar
Russel, A. J. F., Doney, J. M. and Gunn, R. G. 1969. Subjective assessment of body fat in live sheep. Journal of Agricultural Science, Cambridge 72: 451–454.Google Scholar
Staples, L., McPhee, S., Ayton, B., Reeve, J. and Williams, A. 1986. Optimum melatonin treatment to improve reproductive performance of Merino, Border Leicester × Merino and Romney ewes joined in spring and early summer. Proceedings of Australian Society for Reproductive Biology 18: 26 (Abstr.).Google Scholar
Symons, A. M., Arendt, J., English, J. and Poulton, A. L. 1986. Induction of early seasonal sensitivity to melatonin in ewes. Proceedings of the Society for the Study of Fertility Conference, Bristol, pp. 79 (Abstr.).Google Scholar
Vosniakou, A., Tsakalov, P. and Doney, J. M. 1988. Variation in the seasonal oestrous period in three breeds of Greek sheep. Animal Production 46: 509–510 (Abstr.).Google Scholar
Ward, S. J. and Williams, H. L. 1987. Out-of-season breeding in adult Suffolk ewes following light and melatonin treatment. Animal Production 44: 485 (Abstr.).Google Scholar
Wigzell, S., Robinson, J. J., Aitken, R. P. and McKelvey, W. A. C. 1986. The effect of the oral administration of melatonin at two times of the year on ovarian activity in ewes. Animal Production 42: 448–449 (Abstr.).Google Scholar
Wigzell, S., Robinson, J. J., Wallace, J. M. and Aitken, R. P. 1988. Duration of melatonin treatment and ovarian activity in ewes. Animal Production 46: 510 (Abstr.).Google Scholar