Çağatay TEK, Ahmet Zeki EMRELLİ, Huriye HOROZ

Merinos ırkı koyunlarda mevsim dışı melatonin ve progesteron uygulamalarının östrus siklusunun uyarılması ve döl verimine etkisi

Bu çalışmada, mevsim dışı anöstrus koyunlarda progestagen + PMSG ve melatonin uygulamalarının ovaryum aktivitelerinin uyarılması ve bazı üreme parametreleri üzerine etkisinin araştırılması amaçlandı. Materyal olarak 3 yaşlı, 30 baş Merinos ırkı koyun ve 6 baş Merinos ırkı koç kullanıldı. Koyunlar rastgele 3 gruba ayrıldı. 1. gruba (n=10) 18 mg melatonin (Regulin®, Hoechst) kulak arkası implant uygulandı ve 35 gün sonra aralarına arama koçları katılarak östrus gösterenler elde sıfat yöntemiyle tohumlandı. 11. gruba (n=10) progesteron (30 mg FGA) içeren vaginal süngerler 14 gün süreyle uygulandı ve süngerlerin çıkarıldığı gün 500 IU İM PMSO yapılarak aralarına koç katıldı. III. grup (n=10) ise tedavi uygulanmayan kontrol grubunu oluşturdu. Kontrol grubuna (n=10) da diğer gruplarla aynı gün koç katıldı. Koç katımını takiben 5 gün süreyle kan alınarak serum progesteron, östradiol seviyeleri ölçüldü. Serum LH ölçümü için bütün gruplarda koç katımını takiben 48 saat içerisinde 4 saat ara ile kan örnekleri alındı. Tedavi gruplarında östrus belirtileri koç katımından 12 saat sonra başladı ve alınan kan örneklerinde en yüksek östradiol seviyesi koç katıldığı gün gözlendi. Kontrol grubunda östradiol seviyesi 2.,3.,4. günlerde hafif dalgalanma gösterse de öslrus belirtileri gösteren koyuna rastlanmadı. Serum LH seviyesi I. grupta koç katımından 28 saat, II. grupta 32 saat sonra pik yaptı. Serum progesteron seviyesi ise 1. grupta 3. gün, II. grupta 2. gün l ng/ml'nin üstüne çıktı. Kontrol grubunda serum LH ve progesteron seviyesi basal düzeyde seyretti. Kontrol grubu (n=10) koyunlarda östrus ve gebelik gözlenmezken melatonin ve progesteron + PMSG uygulama gruplarında sırasıyla %90, %80 östrus, %90, %70 toplam gebelik ve %77.7, %71.4 ikizlik sağlandı. Sonuç olarak, mevsim dışı anöstrus döneminde Merinos ırkı koyunlarda melatonin ve progesteron içeren vaginal süngerler ile ovaryum aktivitelerinin uyarılabileceği tespit edildi. Melatonin uygulamalarının progesterona göre daha etkili olduğu, bu uygulamaların mevsim dışı anöstrus koyunlarda uygulanmasının yavru verimini artırması açısından yararlı olacağı kanısına varıldı.

The effect of melatonin and progestagen treatments on stimulation of oestrus cycle and reproductive patterns in merino ewes out of the breeding season

In this study, the effects of progestagen + PMSG and melatonin implants on the stimulation of ovarian activity and some of the reproductive parameters were investigated in anoestrus ewes out of the breeding season. Three years old 30 Merino ewes and six rams, were used as material. The ewes were randomly divided into three groups. Eighteen mg melatonin (Regulin®, Hoechst) was implanted to ewes in group I (n=10). After 35 days following implantation, teaser rams were introduced and ewes with oestrus symptoms were selected and inseminated. In group II (n=10) vaginal progesterone sponges (30 mg FGA) were inserted for 14 days and 500 IU PMSG was applied on the withdrawal day. After that rams were introduced and ewes in oestrus were inseminated. The ewes in group III (n=10) were saved as control. Rams were gathered in control group on the same day with the other groups. The ewes and rams were introduced for five days and blood samples were collected once a day from the ewes. Serum progesterone, oestradiol and LH levels were determined by using the R.I.A. technique. The oestrus symptoms were observed after 12 hours following the introduction of rams. The highest oestradiol level was determined on the first day of ram introduction in the treatment groups. Although oestradiol levels in the control group increased slightly on 2nd, 3rd and 4th days, none of the ewes had oestrus symptoms. Serum LH values reached the peak levels after 28 and 32 hours following the introduction of rams for groups I and II, respectively. Serum progesterone level reached the value above 1ng/ml at the 3rd day in group I and at the 2nd day in group II. Serum LH and progesterone levels were at the basal levels during five days following the introduction of rams in the control group. Although no pregnancy was observed in the control ewes (n=10), 90%, 80% oestrus, 90%, 70% pregnancy and 77.7%, 71.4% twinning rates were observed in the melatonin and progestagen+PMSG groups respectively. As a result, the ovarian activities of Merino ewes out of the breeding season can be stimulated with melatonin or progesterone containing vaginal sponges. Also higher pregnancy rates can be provided melatonin applied ewes compared to progesterone treated ewes. In addition, melatonin application is more effective than sponge application in terms of pregnancy rates. In conclusion, in this study melatonin application was found to be more effective than progesterone application in ewes during the non-breeding season. However, both applications would be useful to improve the pregnancy rates in ewes that are in the non-breeding season.

PDF

___

Ak, K.:. Koyunlarda reprodüksiyon ve sun'i tohumlama, in "Reprodüksiyon ve Sun'i Tohumlama" İ. Ü. Vet. Fak. Ders Notu, No: 23: 1994, 179-194, İ.Ü. Vet. Fak. Masaiistü Yayımcılık Ünitesi, İstanbul.
Alaçam, E.: Evcil hayvanlarda üremenin denetlenmesi. In: "Theriogenelogy" Ed: E. Alaçam, 1990, 71 - 91, Nurol Matbaacılık A.Ş. Ankara.
Arthur, G.H., Noakes, D.E., Pearson, H.: Artificial control of cyclic reproductive activity. In:Veterinary Reproduction and Obstetrics. Ed. Bailliere Tindall., 1985, 28-35.
Baştan, A.: Akkaraman ırkı koyunlarda melatonin ve progesteron uygulamalarının reprodüktif performans üzerine etkileri. A.Ü. Sağlık Bilimleri Enstitüsü, Doktora Tezi, 1995, Ankara.
Brih J.H, Roche J.F.: Induction and synchronization of ovulation. In: Reproduction in Farm Animals. Ed. ESE Hafez, 1980, 590-594, Philadelphia.
Bittman, E.L., Kaynard, A.H., Olster, D.H., Robinson, I.E., Yellon, S.M., Karsc, F.J.: Pineal melatonin mediates photoperiodic control of pulsatile luteinizing hormone secretion in the ewe. Neuroendocrinolgy, 1985,40: 409 - 148.
Chemineau ,P., Malpauks, B., Delgadillo, J.A., Guerin, Y., Pavauld, J. P., Tihimonier, J.,Pelletier , J.: Control of sheep and goat repreduction: use of ligt and melatonin. Amin Reprod.Sci., 1992 30: 157-184.
Croby, T.F., O'Callanghan, D.: Effect of melatonin bolus or progestagen sponge plus pregnant mare serum gonadotropin treatment on oestrus response and lambing out come in ewes 11 th.Congr. On Anim Reprod., 1988, 4: 430, Dublin.
Durotoye, L.A., Rajkumar, R., Argo, CM., Nowak, R., Webley, G.E.: Effect of constant-relasemelatonin implants on the onset of oestrous activity and on reproductive performance in the ewe. Anim. Prod., 1991, 52: 48-497.
English, J., Poulton, A.L., Arent J., Symons, A.M.: A comparison of the efficiency of melatonin treatments in advancing oestrus in ewes. J. Reprod. Fertil., 1986, 2: (77), 321-327.
Forcade, F., Zararzaga, L., Abecia, J.A.: Effect of exogenous melatonin and plane of nutrition after weaning on estrous activity, endocrine status and ovulation rate in salz ewes lambing in the seasonal anestrus . Theriogenology, 1995, 43: 1179-1193.
Haresing, W.: Controlling reproduction in sheep. In "C. F. R. Slade and T. L. J. Lawranse feds ], New Developments in Sheep Production, 1990, 14: 23-37, British Society of Animal Production, Occasional Publication , U K.
Haresing, W., Mcleod, B.J.: Physiologycal criteria in genetic selection aseasonality . In " R.B. Land and D. W. Robinson [eds] The Genetics of sheep Reproduction", 1985, 291-300, Butterworths, London.
Kinser, A.R.: Ovarian responses of seasonally anestrous ewes administered progesterone, PMSG, HCG and (or) GnRH. Theriogenology, 1983, 19: (3), 449-464.
Kouimtzis, S.A., Belibasaki, S., Doney, J.M.: Melatonin advances and condenses the onset of seasonal breeding in Greek dairy ewes. Anim. Prod., 1989, 48: 399-405.
Lamning, G.E., Foster, J.P, Bulman, D.C.: Pharmacological control of reproduction cycles. Vet. Rec, 1979, 104: 156-160.
Lincol, G.A.: Control of reproduction in seasonally breeding ruminants. Anim. Prod., 1988, 48: 399-405.
Lincoln, G.A.: Photoperiod-pineal-Hypotalamic relay in sheep. Anim. Reprod. Sci., 1992, 28: 203-217.
Lindsay, D.R.: Reproduction in the sheep and goat. In: "Reproduction in Domestic Animals" Ed. P.T. Cups, 1991,419-515, Academic Press, California.
Lopez-Sebastian, A., Inskeep, E.K.: Response of ewes of meditarranean sheep breeds to subcutaneous implants of melatonin. Li vest. Prod. Sci., 1991, 27: 117-184.
Malpaux, B., Robinson, J.E., Brown, M.B., Karsc, F.C.: Reproductive refractoriness of the ewe to inductive photoperiyod is not caused by inappropriate secretion of melatonin. Biol. Reprod., 1987,36:1333-1341.
Me Donald, L.E.: Veterinary Endocrinology and Reproduction. 1986, 13-24, 320, W.B. Saunders Company, Philadelphia
Pearce, D. T., Martin, G.B., Oldham, CM.: Corpora lutea with a short life span induced by rams in seasonaly anavulatory ewes are prevented by progesterone delaying the preovulaty surge of LH. J. Report. Fertil., 1985, 75: 79-84.
Poulton, A.L.: The proposed use of melatonin in controlled sheep breeding. Aust. J. Biol. Sci., 1988,41:87-96.
Poulton, A.L., Brown, D.C., Thomas, E.M., Kelly, M.I., Symons, A.M., Arent, J.: Use of intraruminal soluble glass bolus containing melatonin for early lamp production. Vet. Rec, 1988, 226-228.
Pineda, M.H.: Reproductive problems of sheep and goat. Veterinary Endocrinology and Reproduction. Lee and Febiger, London. 1989.
Rollang, D.M., Adelman, R.M.: Color change: A non invasive measure of melatonin action. Anim. Reprod .Sci., 1992, 30: 67-89.
Tekin, N., Apel, A.R.G., Yurtaydm, N., Yavaş, Y., Daşkin, A., Keskin, O., Eteni, H.: Östruslarısenkronize edilen koyunlarda sun'i tohumlama yöntemiyle elde edilen döl verimi. A.Ü. Vet. Fak. 1991, Derg., 38: (1-2), 60-73.
Tower,C.J.: Artificial control of breeding in ewes. The compendium, 1993, 15: (4), 642-645.
Wallace, J.M., Robinson, J.J., Wigzell, S., Aitgen, R.P.: Effects of melatonin on the peripheral concentrations of LH and progesterone after oestrus and on conception rate in ewes. J. Endocrinol.,1988, 119:523-530.
Ward, W.R.: The breeding season and the estrous cycles, In "Current Therapy in Theriogenology 2" Ed. D.A. Morrow., 1986, 846-847, W.B. Saunders Comp., Phidelphia.
Wigzell, J., Robinson, J., Aitken, R.P., Mckelvey, M.A.C.: The effect of the oral administration of melatonin at two times of the year on ovarian activity in ewes. Anim Prod., 1986, 42: 448-449, (Abstr.).
Wigzell, S., Robinson, J.J., Wallece, J.M., Aitken, R.P.: Duration of melatonin treatment and ovarian activity in ewes. Anim Prod., 1988, 46: 510, (Abstr.).
Williams, A.H., Mcphee, S.R., Reeve, J.L., Stables, L.D.: Optimum use of subcutaneous melatonin implants to enhance the reproductive performance of seasonal and non-seasonal sheep joined in spring and early summer. Anim. Repord. Sci., 1992, 30: 225-258.
Yuthosastrakosol, P., Palmer, W.M., Howland, B.E.: Luteinizing hormone, oestrogen and progesterone levels in peripheral serum of anoestrus and cyclic ewes as determined by radioimmunoassay. J. Rep. Fert., 1975, 43: 57-65.