Effects of oestrus synchronisation using melatonin and norgestomet implants followed by eCG injection upon reproductive traits of fat-tailed Morkaraman ewes during suckling, anoestrus season

Indução do estro em cutias (Dasyprocta leporina) utilizando-se protocolos à base de prostaglandina isolada ou em associação com análogo de GnRH

RESUMO Comparou-se a eficiência de protocolos para indução de estro em cutias. Em cinco fêmeas, foram administradas duas doses de cloprostenol (5µg) com intervalo de nove dias, via intraperitoneal; em outras cinco, administraram-se 30µg de análogo do hormônio liberador de gonadotrofinas (GnRH), via intravulvar, seguidos de 5µg de cloprostenol, via intraperitoneal, após sete dias e, após mais dois dias, nova dose do análogo de GnRH. A cada três dias, a ciclicidade reprodutiva dos animais foi monitorada, por meio de coleta de sangue, para dosagem hormonal, ultrassonografia ovariana e citologia vaginal. Duas das fêmeas que receberam apenas prostaglandina, as quais estavam em fase luteal no início do tratamento, manifestaram o estro aos três e seis dias após a segunda administração da droga. Já nas fêmeas que receberam a prostaglandina associada ao análogo do GnRH, duas que originalmente estavam em fase luteal apresentaram estro aos quatro dias após o tratamento, e uma outra apenas após 10 dias. Não foram evidenciadas diferenças estatísticas quanto à eficiência dos tratamentos (P>0,05). Conclui-se que, de acordo com os protocolos utilizados, o uso da prostaglandina isolada ou em associação com análogo do GnRH para a indução do estro em cutias D. leporina apresenta eficiência limitada às fêmeas que estejam em fase luteal por ocasião do início do tratamento.

Effects of melatonin implantation on the fertility potentials of Kivircik and Charollais ewes and rams during the non-breeding season

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.

CHARACTERIZATION AND CELULAR PROLIFERATION OF OVARIAN STRUCTURES OF EWES BY THE TECHNIQUE OF AGNOR: OVARIAN MORFOMETRY AND CORRELATIONS

The AgNOR staining technique for nucleolar organizer regions (NORs) is characterized by marking proteins related to ribossomal ribonucleic acid evaluating celular proliferation. The objective was to study the ovarian morphometry and the value of AgNOR thecnique application to evaluate the proliferation of healthy cels from ovarian structures in crossbred ewe. 102 pairs of ovaries were collected and from the largest follicle of each ovary was measured its diameter. From the largest corpus luteum (CL) was measured the diameter and width, classifying the CL in: included, protruberant, massive and cavity, followed by AgNOR staining. The significance level was 5%. It had difference (p<0.05) for the diameter of the largest follicle between right (RO): 4.2±2,3mm and left (LO): 3.6±2,2mm sides. There was a correlation (p<0.01) between the NORs of internal theca (IT) and external theca (ET): RO (0.46) and LO (0.61); NORs of granulosa and IT: RO (0.54) and LO (0.59); and NORs of granulosa and ET: RO (0.34) and LO (0.38). Was conclude that the NORs quantification was appropriate to study the determination of the potential for ovarian structures proliferation, which was similar for right and left sides.