THE CONCEPTION RATE OF EWES AFTER ARTIFICIAL INSEMINATION AT DIFFERENT TIMES DURING OESTRUS

Synchronisation of Ewes at the Second Oestrus after Progestagen Treatment

To determine the change in distribution of ewes exhibiting oestrus at the first and second oestrous cycles after progestagen treatment, data were examined from six experiments in which 430 ewes received progestagens but experienced no fertile mating at the first post-treatment oestrus. Three progestagens, three breeds and two seasons were involved. In all experiments there were more silent heat...

The Synchronization of Oestrus in Sheep in Artificial Insemination Programmes

Timing Ovulation in Ewes Treated with Ovsynch Different Times of PGF2 αInjection during the Breeding Season

This study was carried out at Sakha Animal Production Research Station, during the period from Oct., 2009 to Sept., 2010. Forty Rahmani ewes were divided into three treatment groups: the 1st, 2nd and 3rd treatment groups were intramuscularly injected (Day 0) with 1 mL GnRH analogue followed by an intramuscular injection with 0.7 mL PGF2α5 (G1), 6 (G2) or 7 (G3) days later. A second dose of 1 mL...

Effects of estradiol and oxytocin injection on the efficiency of artificial insemination in Iranian Zel ewes during the breeding season

In sheep industry, pregnancy rate after artificial insemination (AI) declines due to the complex anatomy of the cervix in ewes, such that it might prevent effective intrauterine insemination. At estrus, cervical relaxation occurs to some degree in ewes, which is regulated by the changes in the levels of reproductive hormones. This study aimed to evaluate the effects of estradiol and intravenous...

Effects of GnRH, PGF2α and oxytocin treatments on conception rate at the time of artificial insemination in lactating dairy cows

In several studies, hormones such as gonadotropin-releasing hormone (GnRH), prostaglandins and oxytocin were used to increase pregnancy rate by inducing ovulation and improving the sperm transport in the female reproductive tract in lactating dairy cattle. The objective of this study was to compare the effects of GnRH, prostaglandin F2α (PGF2α) and oxytocin treatments at the time of artificial ...