Less than 25% of calves born in beef herds, on average, are bred through AI. Such low usage of this technology does not bode well for genetic improvement and, most likely, reflects the difficulty and labour requirements for heat detection, assembly of cow(s) for insemination, as well as land fragmentation in beef herds. Despite this, it is well acknowledged that AI allows access to genetically proven sires for key terminal and maternal traits, including ease of calving. One of the primary objectives of the current Beef Data Genomics Programme is to improve the genetic merit of the national beef herd, particularly for maternal traits. Greater use of AI will be necessary to produce higher genetic merit (4 and 5 star) female replacements. Synchronised breeding regimens or synchronisation protocols have been commercially available for more than 25 years.
There is, however, a need for practical, labour-efficient and effective protocols for pasture-based herds, which facilitate treated cows to be bred without recourse to heat detection. A series of large scale, on-farm, oestrous synchronisation studies were conducted in 2014 and 2015, involving 74 beef cow herds with 2,205 cows all over the island of Ireland. Cows that were calved at least 35 days were enrolled in the studies.
Three different synchronisation protocols, all based on insertion of a progesterone releasing intravaginal device for seven days, were compared. All cows were subjected to a single TAI at 72 hours after progesterone device removal. Herd owners were free to use the semen of their choice (non-sexed), thus, resulting in a large number of bulls being used across the studies. Despite this, pregnancy rates ranged from 50-70%, with an overall average of 55% achieved to a single timed insemination. Many herds on the study achieved an 80% pregnancy rate for submitted cows, within the first three weeks of the breeding season (TAI plus any subsequent repeat breedings), thus, condensing the herd calving pattern and reducing calving interval.
Interchem promotes simple synchronization practices where recent Irish trial data* showed a significant economic benefit. Synchronisation will also support Teagasc’s 6 week in calf rate of 70%. Interchem (Ireland) Ltd is the only veterinary supplier in Ireland to offer a full range of fertility products for bovine livestock. For further information on Interchem’s full fertility range, please contact your local Vet or call us on 01 451 8959