Estrus Synchronization and Artificial Insemination with Fresh and Chilled Semen in Assaf Ewes

Abstract

This paper aims to study the efficiency of two short-term progestagen (FGA vs. MAP) + eCG treatments in estrus synchronization and artificial insemination (AI) with fresh or chilled semen in Assaf ewes fertility rate. All ewes received a subcutaneous implant of exogenous melatonin 45 days before been treated with short-term progestagens + eCG. By June 1 st , ewes were divided in two groups: half was treated with an intravaginal sponge impregnated with 20 mg of FGA and the other half with an intravaginal sponge impregnated with 60 mg of MAP. Progestagen treatments lasted for 6 days. At sponge withdraw, all ewes were injected with 750 IU of eCG. Ovarian activity was assessed by plasmatic progesterone levels before and after progestagens + eCG treatment. Semen was collected by electro ejaculation and extended with Andromed ® or OviXcell ® . AI was performed 55 hours after eCG administration with fresh or chilled semen. During AI several factors were assessed: vagina mucosa color and lubrication, external cervical Os type, cervical mucous viscosity, semen deposition place and seminal cervix outflow. Semen was deposited as deep as possible without distress or trauma cervix mucosa. All Assaf ewes presented cyclic activity before progestagen + eCG treatments (2 nd fortnight of May).Short-term progestagen + eCG treatments were equally efficient (100.0%). About 76.5% of Assaf ewes were pregnant 41 days after AI. Fertility rate was influenced by external Os type, semen deposition place and seminal cervix outflow. However, this rate was not conditioned by vaginal color or lubrication, cervical mucus viscosity, semen preservation technic and semen extender.

Comparative advantages of cervical insemination over natural mating on production of crossbred lambs for export market.

“…However, it was lower than values obtained by Mekuriaw et al (2005) who reported pregnancy rates of 70.6 and 70.4% in Dorper sheep synchronized with MAP and FGA sponges respectively. Similarly Fornazari et al (2018) reported pregnancy rates of 76.5% in Assaf sheep synchronized with progestagen sponges. However, the current result was higher than value obtained by Olivera-muzante et al (2011) who reported a pregnancy rate of 51% synchronized with two doses of PGF2α 7 days apart and inseminated cervically with fresh semen.…”

Comparative study between the excision-ligation and autoligation of vas deferens technique for teaser rams preparation

“…Improving the reproductive quality of the livestock industry is one of the main objectives of veterinarians [1]. Basically, fixed time artificial insemination [2] and estrous synchronization followed by superovulation [3] are used top quality semen that preserved as a liquid [3] or frozen form [4]. However, sometimes, small ruminants tend to silent heat [5], so these techniques might need to determine the estrous using estrous detector.…”