A method of estrus synchronization is the use of progestin, which can include vaginal implants or oral products, which will trigger the estrous cycle in cows and heifers (Rasby & Deutscher 2016). The treatment, which will inhibit estrus and therefore ovulation for up to 14 days, is often followed by the introduction of prostaglandin or gonadotrophins (Mallory et al. 2010; Powell et al. 2012). The use of progestin while synching a herd is recommended if many of the animals will be anestrus as exposure will insure that the estrous cycle will be of normal length after insemination (Bridges et al. n.d.).
A second method of synchronization is the used of prostaglandin. To increase chance of pregnancy during a timed artificial insemination, cows can receive 2 injection of prostaglandin 12-14 das prior to AI (Bruno et al. 2013). According to Rasby & Deutscher (2016), the animal should be bred 12 hours after exhibiting signs of heat, either after the first or second injection. However, if a cow was inseminated after the first injection, she must not receive a second dose as this will likely terminate a possible pregnancy (Rasby & Deutscher