Breeding Replacement Heifers
Maiden heifers are the most fertile animals in the herd and have the highest EBI. Therefore Teagasc recommends targeting your heifers with sexed or conventional dairy AI to maximise the rate of genetic gain in your herd. In the video clip here, Stephen Moore, Teagasc Researcher explains
Another advantage of breeding replacement heifers to AI is that the calving ease or difficulty of such bulls is well established. New and improved measures of calving difficulty have been available since their introduction by ICBF around three years ago. These figures are displayed in the SireAdvice app on ICBF or on the current Active Bull List. The figure that you are looking for is the direct calving difficulty of bulls on heifers is displayed. Teagasc recommends that in most circumstances only bulls identified as having a low risk of calving difficulty in heifers are bred to your replacement heifers. The following table shows the calving difficulty details for a bull on the Active Bull list.
Table 1 Calving difficulty details for a bull on the Active Bull list.
The heifer calving difficulty percentage is 6.5% with a reliability of 71% while that for the bulls use on cows is recorded as 1.9% with a reliability of 89% (more dairy calving records on dairy cows are available for the sire). Typically calving difficulty is lower for cows than for heifers. Importantly the bull is listed as low risk of dairy heifer calving difficulty and so safe to use on maiden heifers.
In this short clip, originally broadcast in 2021, Stephen Moore, Teagasc Researcher explains how, by using dairy sires for at least one round of inseminations, the number of beef stock bulls needed to breed the repeating heifers can be reduced typically by two thirds for each round of AI used. Laura Hannon, dairy farmer from Co. Meath also speaks about her plan to AI her heifers.
Keep an eye on Teagasc Daily over the next couple of weeks for more information on Breeding.
The Teagasc Dairy Specialists issue an article on a topic of interest to dairy farmers every Monday here on Teagasc Daily. Find out more about Breeding & Genetics here