Synchronization and superovulation are commonly used to obtain large numbers of embryos for experimental and practical purposes. This study compared the number, quality, and in vitro development of embryos recovered from gilts following single or double estrus synchronization and superovulation. Prepubertal gilts from the single synchronization group were injected with 1500 I.U. PMSG and 1000 I...

Introduction The development of effective methods of synchronizing estrus and ovulation has been based on our understanding of the physiological and hormonal mechanisms controlling the estrous cycle and the initiation of estrous cyclicity and prepuberty in heifers and postpartum cows. Although estrus synchronization products (PGF2, MGA, CIDR and GnRH) and protocols have changed over time, the ...

Estrus has been synchronized in cattle with progestogens, prostaglandins (prostaglandin F2 alpha and its analogues), progestogen-estrogen combinations and progestogen-prostaglandin combinations. Progestogens administered for 14 to 20 d are effective in synchronizing estrus; however, fertility at the synchronized estrus is subnormal. Duration of progestogen treatment can be reduced by combining ...

treatments the cows were randomly assigned to two groups. One group of cows (n= 281) was fed 0.5 mg of melengestrol acetate (MGA) per head per day for ten days while the other group of cows (n= 257) served as controls. All cows were bled for progesterone concentrations at the beginning of the MGA feeding (d -21), before the SMB treatment, and at the time of artificial insemination (AI). Twenty-...

using melatoninin ewes of iran black breed, this study aimed to compare the reproduction and production performances in lambing program of two and three times per years for duration of two years. a hundred ewes allocated to two parallel groups: group a (ewes in three lambing managing system using melatonin) and group b (ewes in two lambing managing system without using melatonin). to induce the...

Five hundred forty-six postpartum, multiparous and primiparous beef cows at the University of Illinois Dixon Springs Agricultural Research Center (Simpson, Illinois) were used in this experiment. All cows were administered Syncro-Mate B (SMB) for estrus synchronization and were bred from a timed AI about 48 hours after SMB implant removal. Blood samples were collected from all cows on days 0 (A...