A series of large-scale on-farm synchronization studies for Fixed Time AI (FTAI) were conducted by Teagasc in 2014 and 2015 and involved 74 suckler herds all over the island of Ireland.
The trials were run in both autumn and spring-calving herds with some 2205 cows involved in the studies.
Three different synchronization protocols were compared and all cows were subjected to FTAI, 72 hrs after PRID removal.
Outlining the results at the National Beef Conference in Athlone, Teagasc’s Mervyn Parr said overall average herd pregnancy rates ranged from 50-70% in the trials.
He said the expected conception rates vary from 30- 75%, with an average of 50-55% of cows becoming pregnant.
Cows that fail to become pregnant to the synchronized breeding, that repeat and were re-inseminated usually have normal fertility (65-75% conception rate) at the repeat heat.
According to Teagasc FTAI costs around €25-35/cow treated. However, it notes that vet call out fees and ai costs are additional.
Despite this Teagasc also says that the costs of keeping a stock bull for a year is in the region of €52.
- Cows are in a moderate BCS score (2.5 –3.0) at time of treatment. It is equally important that cows are a minimum of 35 days calved at the time of PRID or CIDR insertion and are on a good plane of nutrition (plentiful supply of grass) for a minimum of 3-4 weeks prior to, during and after treatment.
- Synchronization should only be used in herds where the levels of management and in particular heat detection skills are high in order to detect heats and particularly repeat heats. Alternatively, a bull should be turned out with cows following the synchronized AI.
- It is vitally important that high fertility semen is used and the competence of the inseminator is high. Semen must be thawed carefully (15 seconds in water at 35OC) and inseminated into the cow within 1-2 minutes of thawing. The correct site for semen deposition is in the common body of the uterus. Each straw should be thawed separately.