Effects of long-acting melatonin implants on the reproductive performance of Corriedale, Borderdale, Romney, Coopworth, and Perendale ewes in New Zealand

References

• Averill , R. L. W. 1959 . Ovulatory activity in mature Romney ewes in Otago . New Zealand journal of agricultural research , 2 : 575 – 583 .
   Google Scholar
• Croker , K. , Dunstan , E. , Reeve , J. , Williams , A. H. , McPhee , S. R. , Bell , A. , Ayton , B. M. , Wagg , M. , Pollard , T. , Parker , J. , Foote , M. , Ritar , A. and Staples , L. D. Field studies of the use of melatonin implants to improve lambing percentages in spring joined merino and crossbred ewes . Proceedings of the Australian Society of Reproductive Biology . Vol. 19 , pp. 21 – 21 .
   Google Scholar
• Ducker , M. J. , Thwaites , G. J. and Bowman , J.C. 1970 . Photoperiodism in the ewe. 2. The effects of various patterns of decreasing daylength on the onset of oestrus in Clun Forest ewes . Animal production , 12 : 115 – 123 .
   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 .
   PubMedGoogle Scholar
• Haresign , W. , Peters , A. R. and Staples , L. D. 1990 . The effect of melatonin implants on breeding activity and litter size in commercial sheep flocks in the U. K . Animal production , 50 : 111 – 121 .
   Google Scholar
• Jackson , G. L. , Gibson , M. and Kuehl , D. 1988 . Photoperiodic disruption of photorefractoriness in the ewes . Biology of reproduction , 38 : 127 – 134 .
   PubMed Web of Science ®Google Scholar
• Jordan , B. T. , Hanrahan , J. P. and Roche , J. F. 1990 . The effect of melatonin implantation in the middle of the breeding season on the subsequent reproductive activity of Scottish Blackface ewes . Animal reproduction science , 23 : 41 – 48 .
   Google Scholar
• Kelly , R. W. , Allison , A. J. and Shackell , G. H. 1976 . Seasonal variation in oestrous and ovarian activity of five breeds of ewe in Otago . New Zealand journal of experimental agriculture , 4 : 209 – 214 .
   Google Scholar
• Kennaway , D. J. , Gilmore , T. A. and Seamark , R. F. 1982 . Effect of melatonin feeding on serum prolactin and gonadotrophin levels and the onset of seasonal estrous cyclicity in sheep . Endocrinology , 110 : 1766 – 1772 .
   PubMed Web of Science ®Google Scholar
• Knight , T. W. , Hall , D. R. H. and Wilson , L. D. Effect of teasing and nutrition on the duration of the breeding season in Romney ewes . Proceedings of the New Zealand Society of Animal Production . Vol. 43 , pp. 17 – 19 .
   Google Scholar
• Knight , T. W. and Hight , G. K. 1976 . Variations in the fertility over the joining period of ewes on hill country . New Zealand journal of agricultural research , 19 : 211 – 216 .
   Web of Science ®Google Scholar
• Knight , T. W. , Lynch , P. R. , Hall , D. R. H. and Hockey , H-U. P. 1988 . Identification of factors contributing to the improved lamb survival in Marshall Romney sheep . New Zealand journal of agricultural research , 31 : 259 – 211 .
   Web of Science ®Google Scholar
• Knight , T. W. , Kannegieter , S. G. and Hamilton , G. J. Breeding season of Romney and Poll Dorset ewes at different locations and the reproductive penalties of a June joining . Proceedings of the New Zealand Society of Animal Production . Vol. 49 , pp. 265 – 270 .
   Google Scholar
• Legan , S. J. and Karsch , F. J. 1980 . Photoperiodic control of seasonal breeding in ewes: modulation of the negative feedback action of estradiol . Biology of reproduction , 23 : 1061 – 1068 .
   PubMedGoogle Scholar
• Lopez Sebastian , A. and Inskeep , E. K. 1991 . Response of ewe of Mediterranean sheep breeds to subcutaneous implants of melatonin . Livestock production science , 27 : 177 – 184 .
   Google Scholar
• Nett , T. M. and Niswender , G. D. 1982 . Influence of exogenous melatonin on seasonality of reproduction in sheep . Theriogenology , 17 : 645 – 653 .
   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 .
   PubMedGoogle Scholar
• Poulton , A. L. , Symons , A. M. , Kelly , M. I. and Arendt , J. 1987 . Intraruminal soluble glass boluses containing melatonin can induce early onset of ovarian activity in ewes . Journal of reproduction and fertility , 80 : 235 – 239 .
   PubMedGoogle Scholar
• Quinlivan , T. D. and Martin , C. A. 1971 . Oestrous activity and lamb production in New Zealand Romney ewe . Australian journal of agricultural research , 22 : 497 – 511 .
   Google Scholar
• Reeve , J. , Williams , A. H. , McPhee , S. R. , Peake , R. and Staples , L. D. The effect of season on the response of Border Leicester x Merino (BL × M) ewes to subcutaneous implants of melatonin . Proceedings of the Australian Society of Reproductive Biology . Vol. 18 , pp. 25 – 25 .
   Google Scholar
• Robinson , J. E. and Karsch , F. J. 1984 . Refractoriness to inductive day length terminates the breeding season of the Suffolk ewes . Biology of reproduction , 31 : 656 – 663 .
   PubMed Web of Science ®Google Scholar
• Robinson , J. E. and Karsch , F. J. 1988 . Timing the breeding season of the ewe: what is the role of daylength? . Reproduction nutrition development , 28 ( 2B ) : 365 – 374 .
   PubMedGoogle Scholar
• Smith , J. F. , McGowan , L. T. , Dobbie , J. L. and Smart , S. H. Seasonal pattern of ovulation in Merino, Romney and Merino × Romney ewes . Proceedings of the New Zealand Society of Animal Production . Vol. 49 , pp. 249 – 254 .
   Google Scholar
• Staples , L. D. , McPhee , S. R. , Ayton , B. M. , Reeve , J. and Williams , A. H. Optimum melatonin treatment to improve reproductive performance of Merino, Border Leicester × Merino and Romney ewes joined in spring and early summer . Proceedings of the Australian Society of Reproductive Biology . Vol. 18 , pp. 26 – 26 . (Abstr).
   Google Scholar
• Staples , L. D. , McPhee , S , Kennaway , D. J. and Williams , A. H. 1991a . “ Practical applications for controlled release melatonin implants in sheep ” . In Advances in pineal research Vol. 6 , in press.
   Google Scholar
• Staples , L. D. , McPhee , S , Kennaway , D. J. and Williams , A. H. 1991b . The influence of exogenous melatonin on the seasonal patterns of ovulation and oestrus in sheep . Journal of animal production science , in press.
   Google Scholar
• Staples , L. D. , McPhee , S. R. , Reeve , J. , Kennaway , D. and Williams , A. H. A novel melatonin treatment to enhance prolificacy in sheep . Proceeding of the Society for the Study of Fertility . Vol. 130 , (Abstr.).
   Google Scholar
• Wilkins , J. F. , Fowler , D. G. , Bindon , B. M. , Piper , L. R. , Hall , D. G. and Fogarty , N. M. Measuring foetal loss with real time scanning . Proceedings of the Australian Society of Animal Production . Vol. 15 , pp. 768 – 768 .
   Google Scholar
• Williams , A. H. , Bell , A. , McPhee , S. , Ayton , B. M. and Staples , L. Ewes treated with melatonin implants to improve spring joining may have lowered performance if rejoined in Autumn . Proceedings of the Australian Society of Reproductive Biology . Vol. 19 , pp. 23 – 23 . (Abstr).
   Google Scholar
• Williams , A. H. , McPhee , S. R. , Ayton , B. M. and Staples , L. D. Dose dependent effects of continuous melatonin administration on the seasonal pattern of oestrous cyclicity and ovulation rate in Corriedale ewes . Proceedings of the Australian Society of Reproductive Biology . Vol. 18 , pp. 27 – 27 .
   Google Scholar
• Williams , A. H. , McPhee , S. R. , Reeve , J. and Staples , L. D. 1991 . Optimum use of subcutaneous melatonin implants to enhance the reproductive performane of seasonal and non seasonal sheep joined in Spring and early Summer . Journal of animal production science , in press.
   Google Scholar
• Yeates , N. T. M. 1959 . The breeding season of the sheep with particular reference to its modification by artificial means using light . Journal of agricultural science, Cambridge , 39 : 1 – 42 .
   Google Scholar