This study examined the effect of melatonin implantation during the non-breeding season on the reproductive performance of ewes and the testicular dimensions of rams. In seasonally anestrus Kivircik and Charollais ewes and rams were subjected to melatonin. Estrus response was significantly higher in treated than control ewes of both breeds (p<0.001). The pregnancy rate was significantly lower (p<0.001) in the control than in the treated animals. The twinning rate was significantly lower in melatonin implanted Kivircik than Charollais ewes (p<0.05). The testicular dimensions after 42 days of melatonin treatment increased in both breeds. Scrotal length (SL) increased in Kivircik and Charollais rams (p<0.01). The increase in scrotal circumference (SC) was more marked in the Charollais (P<0.01) than in the Kivircik rams. There was a large increase in testicular volume (TV) in both Kivircik (p<0.01) and Charollais (p<0.001) rams. This study shows that melatonin implants can be applied to induce estrus in ewes approximately four months earlier than breeding season. Melatonin implantation in the non-breeding season significantly increased testicular dimensions in Kivircik and Charollais rams thus increasing their reproductive potential.
Republic of Turkey Ministry of Food, Agriculture and Livestock, 59000, Tekirdag, Turkey
Bibliografia
Abecia JA, Valares JA, Forcada F, Palacin I, Martin S, Martino A (2007) The effect of melatonin on the reproductive performance of three sheep breeds in Spain. Small Ruminant Res 69: 10-16.
Casao A, Vega S, Palacin I, Perez R, Lavina A, Quintin FJ, Sevilla E, Abecia JA, Cebrian- Perez JA, Forcada F, Muino-Blanco T (2010) Effects of melatonin implants during non-breeding season on sperm motility and reproductive parameters in Rasa Aragonesa rams. Reprod Domestic Anim 45: 425-432.
Chemineau P, Beltran de Heredia I, Daveau A, Bodin L (1996) High repeatability of the amplitude and duration of the nycthemeral rhythm of the plasma melatonin concentration in the Ile-de-France ewe. J Pineal Res 21: 1-6.
Chemineau P, Guillaume D, Migaud M, Thiery JC, Pellicer-Rubio MT, Malpaux B (2008) Seasonality of reproduction in mammals: intimate regulatory mechanisms and practical implications. Reprod Domestic Anim 43(s2): 40-47.
DeNicolo G, Morris ST, Kenyon PR, Morel PC, Parkinson TJ (2008) Melatonin-improved reproductive performance in sheep bred out of season. Anim Reproduction Sci 109: 124-133.
Egerszegi I, Sarlos P, Ratky J, Solti L, Faigl V, Kulcsar M, Cseh S (2014) Effect of melatonin treatment on semen parameters and endocrine function in Black Racka rams out of the breeding season. Small Ruminant Res 116: 192-198.
Emrelli AZ, Horoz H, Tek C (2003) The effect of melatonin and progestagen treatments on stimulation of oestrus cycle and reproductive patterns in merino ewes out of the breeding season. J Fac Med Vet Istanbul University 29: 267-275.
Endale M, Hailemariam M, Tegegne A (2009) A study on testicular characteristics of ram lambs of Arsi breed fed on two maize varieties (QPM and BH540). Ethiop J Sci 32: 37-44.
Forcada F, Zuniga O, Abecia JA (2002) The role of nutrition in the regulation of LH secretion during anestrus by the serotoninergic and dopaminergic systems in Mediterranean ewes treated with melatonin. Theriogenology 58: 1303-1313.
Haresign W, Peters AR, Staples LD (1990) The effect of melatonin implants on breeding activity and litter size in commercial sheep flocks in the UK. Anim Sci 50: 111-121.
Haresign W (1992) Responses of ewes to melatonin implants: importance of the interval between treatment and ram introduction on the synchrony of mating, and effects on ovulation rate. Anim Sci 54: 41-45.
Horoz H, Kasikci G, Ak K, Alkan S, Sonmez C (2003) Controlling the breeding season using melatonin and progestagen in Kivircik ewes. Turk J Vet Anim Sci 27: 301-305.
Kridli RT, Abdullah AY, Shaker MM (2006) Sexual performance and reproductive characteristics of young adult Awassi, Charollais-Awassi and Romanov-Awassi rams. Sheep Goat Res J 21: 12-16.
Kridli RT, Momany SM, Abdullah AY, MuwallaMM (2007) Sexual behaviour of yearling Awassi, Charollais x Awassi and Romanov x Awassi rams exposed to oestrus Awassi ewes. Trop Anim Health Prod 39: 229-235.
Mandiki SN, Derycke G, Bister JL, Paquay R (1998) Influence of season and age on sexual maturation parameters of Texel, Suffolk and Ile-de-France rams. 1. Testicular size, semen quality and reproductive capacity. Small Ruminant Res 28: 67-79.
Padeanu I, Voia S, Gavojdian D, Fratila I, Mircu C, Bratu I, Pascal C, Sauer I (2011) Effect of using melatonin implants on reproductive performances in Turcana ewes. Anim Sci Biotech 44: 387-389.
Palacin I, Abecia JA, Forcada F, Casao A, Cebrian JA, Muino T, Palacios C, Pontes JM (2008) Effects of exogenous melatonin treatment on out-of-season ram fertility. Ital J Anim Sci 7: 199-206.
Rosa HJ, Silva CC, Bryant MJ (2012) The effect of melatonin treatment in rams on seasonal variation of testicular size and semen production parameters. Small Ruminant Res 102: 197-201.
Sarlos P, Egerszegi I, Balogh O, Molnar A, Cseh S, Ratky J (2013) Seasonal changes of scrotal circumference, blood plasma testosterone concentration and semen characteristics in Racka rams. Small Ruminant Res 111: 90-95.
Ucar O, Kaya M, Yildiz S, Onder F, Cenesiz M, Uzun M (2005) Effect of progestagen/PMSG treatment for oestrus synchronization of Tuj ewes to be bred after the natural breeding season. Acta Vet Brno 74: 385-393.
Uslu BA, Tasal I, Gulyuz F, Sendag S, Ucar O, Goericke-Pesch S, Wehrend A (2012) Effects of oestrus synchronization using melatonin and norgestomet implants followed by eCG injection upon reproductive traits of fat-tailed Morkaraman ewes during suckling, anoestrus season. Small Ruminant Res 108: 102-106.
Zuniga O, Forcada F, Abecia JA (2002) The effect of melatonin implants on the response to the male effect and on the subsequent cyclicity of Rasa Aragonesa ewes implanted in April. Anim Reprod Sci 72: 165-174.