Economic evaluation of Hereford cattle breeding schemes incorporating direct and indirect measures of feed intake

Abstract

A deterministic approach was used to evaluate the effect of incorporating direct and indirect measures of feed intake as additional selection criteria in breeding schemes for Hereford cattle. A 2-tier nucleus breeding scheme consisting of a nucleus and a commercial sector was assumed. Four breeding objectives specific to Australian Hereford cattle were considered. These addressed production systems that targetted 4 markets (Domestic Supermarket, 'Hereford Prime', Short-fed Export, and Long-fed Export). The breeding objectives differed especially in the feed cost involved for differing amounts of grain finishing and in the extent to which marbling is valued by the market (from none to quite a lot). The breeding schemes evaluated differed in the measures available for use as selection criteria. The schemes ranged from one that utilised growth, scanned carcass and fertility criteria currently available to Australian cattle breeders (Scheme 1) to one which also incorporated residual feed intake (RFI) and blood serum insulin-like growth factor I (IGF-1) criteria (Scheme 5). The latter scheme included selection of sires for the nucleus using a 2-stage selection process, with a proportion of bulls selected after weaning for measurement of RFI. Schemes utilising either IGF-1 or RFI or both as criteria generated additional genetic gain and profitability for each breeding objective. Profit was optimal across all the Hereford cattle breeding objectives when the top 5% of bulls was measured for RFI after being selected on an index incorporating IGF-1 and other information available on the bull and its relatives at a young age. Further increase in the proportion of bulls measured for RFI for consideration in the second selection stage resulted in a slow decline in profit per cow in the population and a flat response in genetic gain. In the absence of more breed-specific information, these results may also have application in breeds other than Herefords.