A new product containing a GnRH-analogue for use in cattle fertility improvement programmes has been launched by Zoetis.
Acegon is a 50µg/ml solution of gonadorelin, a natural GnRH analogue. From four to 10 hours after oestrus observation, a 2ml treatment is recommended followed by insemination at least two hours, and no more than 24, later.
According to Zoetis vet Dr Jude Roberts, the dominant follicle present at oestrus responds to Acegon treatment resulting in ovulation within 24 hours. “This coincides with high sperm quality shortly after insemination and has been found to increase the probability of pregnancy,” she says. [Ref 1]
Under the product licence, treatment can also be given 12-days post-AI. “This encourages formation of an additional corpus luteum on the ovary, which produces additional progesterone supporting the maintenance of pregnancy,” Dr Roberts adds. “This can lead to increased pregnancy rates, up to double those of untreated animals, when given to certain repeat breeder animals.” [Ref 2]
The product licence also covers treatment of ovarian follicular cysts at a dose rate of 2-3ml, with re-treatment at one to two week intervals if necessary, to restore normal ovarian cycling. Dr Roberts points out that each of the three indications mean the product can be used to improve fertility in specifically targeted groups of cattle.
1 WF Morgan and IJ Lean, 1993. Gonadotrophin-releasing hormone treatment in cattle: a meta-analysis of the effects on conception at the time of insemination. Austral Vet J;70:205-209.
2 S Willard et al, 2003. The effects of GnRH administration post insemination on serum concentrations of progesterone and pregnancy rates in dairy cattle exposed to mild summer heat stress. Theriogenology;59:1799-1810.