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NZAEL Confirms Young Bull BW Discounting Advice

17 August 2010

NEW ZEALAND - NZAEL (New Zealand Animal Evaluation Limited) says results of tests carried out have confirmed the potential for some over-estimation of the breeding worth of top-ranked young bulls prior to progeny testing.

Since June 2009 NZAEL has included genomic data along with the traditional ancestry and progeny test data to calculate the breeding worth (BW) of bulls. It has now completed an examination comparing the daughter performance of young bulls with the predictions based on ancestry and genomic data.

“NZAEL advised farmers in June this year that they should discount all young bull teams without progeny test daughters by 15-25 BW units. The latest work confirms that advice. NZAEL acknowledges that the need for this adjustment is undesirable, and is working urgently to resolve the issue.” says Bill Montgomerie, DairyNZ’s NZAEL Manager.

“This advice includes LIC ‘DNA-proven’ teams which have genomic data in their BW, and also young bull teams with no genomic data in their BW marketed by companies including Liberty and CRV Ambreed.”

He says for farmers who wish to select bulls on the basis of ancestry and progeny test only, NZAEL has published a list (named PA_PT) which ranks all NZAEL-enrolled bulls without inclusion of any genomic data. This list is available on the NZAEL website and through the AI companies.

“NZAEL’s researchers are currently using the results of the validation testing to investigate ways that the tendency for over-estimation of young AE-enrolled bulls can be reduced in the AE system. We are giving this matter our urgent attention and anticipate that these methods will be introduced in the 2010/11 season following testing with the industry. Of course we will advise farmers of any changes before they are made.”

Prof Hugh Blair from Massey University, who chairs NZAEL’s Advisory Committee, believes that including genomic data into BW is of value to NZ dairy farmers. He says this value will increase in the future as methods improve and more companies use genomic data for bull selection.

“The research is showing that inclusion of genomic data improves prediction of daughter performance of young bulls over use of ancestry data alone. The trend to genomic data use is occurring worldwide and NZAEL believes that the NZ industry needs to be using this technology quickly and accurately to maintain our competitive position.”

TheCattleSite News Desk


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