A review of synchronization of estrus in postpartum cattle.

Abstract

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 it with an estrogen. Syncro-Mate B is a progestogen-estrogen combination that results in a tightly synchronized estrous response. Prostaglandins can be used in double- or single-injection programs. Fertility of the estrus after prostaglandin treatment is similar to that of controls. Estrus also has been synchronized effectively by combining a 5- to 9-d progestogen treatment with prostaglandin at or near the end of treatment. When prostaglandin is used alone, cattle in the late stages of the luteal phase (d 11 to 15 of the estrous cycle) at the time of prostaglandin injection have a higher estrous response and may be more fertile than those injected with prostaglandin in the early part (d 6 to 9) of the luteal phase. More recently, a 14-d progestogen treatment has been combined with a prostaglandin injection given 16 to 18 d after progestogen withdrawal. This system places cattle in the late luteal phase of the estrous cycle at the time of prostaglandin injection and has resulted in an estrus with greater fertility than that immediately following progestogen treatment.

The effect of buserelin injection 12 days after insemination on selected reproductive characteristics in cows

“…These varied responses may have been associated with different proportions of two and three-wave cycles in different populations of cows. In addition, different results obtained in various studies may be influenced by age, nutrition, suckling and season described as Odde (1990) and Bülbül and Ataman (2009).…”

Reproductive parameters in Holstein dairy cows treated with three resynchronization methods

“…Poorer fertility after timed AI (TAI) often was attributed to insufficient synchrony of estrus and ovulation to allow appropriate timing of AI relative to ovulation [8]. Deficiencies in luteal function [6], either before or after insemination, are associated with reduced fertility in beef [21] and dairy cattle [10]. In addition, concentrations of progesterone (P4) in blood 34 to 48 h before the preovulatory surge of LH were greater in cows that conceived compared with those that failed to conceive [7].…”

Clinical Approach to the Repeat Breeder Cow Syndrome

“…Also, defective follicle recruitment during the middle-and late-luteal phases has been suggested as a cause of anovulation. An abnormal hormone environment may promote continuous development in the dominant follicle, impairing follicular function and oocyte quality, and thus reducing fertility (Odde, 1990;Stock & Fortune, 1993).…”