Background: Presynchronization could enhance fertility in timed breeding programs. The best presynchronization method has to justify biological requirements and to provide practical and economic advantages. OBJECTIVES: Present study investigated the effectiveness of presynchronization with equine chorionic gonadotropin (eCG) before ovsynch (eCG-ovsynch) compared to conventional presynch-ovsynch...

We studied two mating systems for a large-scale breeding colony of cynomolgus monkeys: (i) a 3-day timed system that keeps one female and one male together in a cage for 3 days beginning 11 days after menstruation, and (ii) a 7-day timed system beginning 9 days after menstruation. Regardless of the mating system used, we propose a practical definition of an infertile female as one that does not...

Angus-cross, fall-calving beef cows (n = 153) were used in this experiment. The objective was to determine whether incorporating a period of corn stover and dried distiller grains with solubles (DDGS) feeding into a preexisting nutritional program that included grazing stockpiled tall fescue affects reproductive performance and progeny growth. On Julian d 267 cows were stratified and allotted b...

The experiments which have provided insight into the role of the pineal gland and melatonin in sheep reproduction are reviewed. There is now strong evidence that timed daily melatonin administration and continuous administration via implants are equally effective in promoting the same physiological consequences as short daylength. Thus melatonin treatments lasting six weeks can result in an adv...

The present study was designed to evaluate the effect of Ovsynch protocol in repeat breeding crossbred Jersey cows. A total of thirty four repeat breeding cross bred Jersey cows were subjected to Ovsynch protocol with timed artificial insemination. The pregnancy rate in Ovsynch protocol was 58.82 per cent where as it was 29.41 per cent in control group. Thus, the Ovsynch protocol can be effecti...

Objectives were to compare the effect of presynchronization and resynchronization methods on fertility responses of grazing dairy cows at first and second artificial insemination (AI) and pregnancy rate during the entire breeding season. Lactating dairy cows (n = 1,263) in 2 seasonal grazing farms were blocked, within farm, by parity, breed and days in milk. Within each block, cows were randoml...

Previous research indicated that the size of the ovulatory follicle at the time of insemination significantly influenced pregnancy rates and embryonic/fetal mortality after fixed-timed AI in postpartum cows, but no effect on pregnancy rates was detected when cows ovulated spontaneously. Our objective was to evaluate relationships of fertility and embryonic/fetal mortality with preovulatory foll...

Reproduction continues to be a critical component to maintain a dairy farm economically viable. For every farm and for every cow, there is an optimum time for pregnancy, which is mostly influenced by level of production, persistency of lactation, and parity. In general, as production decreases, lactation number increases, and persistency of lactation decreases, cows should be bred sooner postpa...