Inbreeding worries as Oman rules
Published 23/02/2010 | 05:00
Concern is mounting about the dominance of Holstein bull O-Bee Manfred Justice (Oman or OJI) and his sons on the ICBF dairy bull listings.
It is understood that the number of Oman sons on the spring active bull list, due to be published tomorrow, is continuing to rise. The autumn 2009 active bull list showed no less than 34 Oman sons, close to half the entire list.
However, the spring 2010 list is expected to show a higher number of his sons than last year.
While the Oman effect so far has been to greatly increase genetic gain within the Irish herd, the long-term effect of his dominance in the bull rankings could be to increase the level of inbreeding in the herd.
According to the ICBF, one of the downsides of genetic gain is that related animals tend to be selected (as sires of sons and bull mothers) within each generation.
Unless this problem is managed inbreeding will result, with harmful effects on overall profit in the longer term.
Oman, which has an EBI of €280.07 in the February 2010 evaluations, is so successful at producing high EBI offspring that his sons are dominating the top rankings.
However, the danger is that when Oman's daughters begin to calve down, there will be no unrelated bulls of high genetic merit to service them.