Simultaneous Selection for Milk and Beef Production Among Holstein-Friesians

Abstract

A selection index combining milk and beef production traits, such that progress in aggregate economic value is maximized, was constructed for Holstein bulls. The index for milk was IM = 1.11Xt + .997X2 while the index for beef trait was IB = .008X~ + .619X~ where X~ is the daughters' average lactation yield (kg) and X2, bulls' body weight at 15 mo (kg).The relative genetic progress from simultaneous selection for milk and beef traits with different emphasis was estimated. Expected genetic progress in beef production (body weight at 15 mo) dedined with increasing selection on milk and vice versa. Expected genetic progress, however, did not fall below onethird of maximum genetic progress (100%) for either milk or beef, regardless of the emphasis of seleetion.Based on current milk and beef values, ignoring milk and selecting solely for beef would give the highest genetic progress in total economic value but quite slow genetic progress in total protein production. Ignoring beef and seleering solely for milk would give the highest genetic progress in total protein production and a fairly high genetic progress in total economic value. A 1:7 beef to milk emphasis per standard deviation seems to be most appropriate since it results in large genetie progress in both total protein and total economie Value.

Genetic Aspects of Beef Production among Holstein-Friesians Pedigree Selected for Milk Production1

“…It appears that at least some emphasis in selection for beef could be incorporated into the existing DHI program to improve total protein production. The relative genetic progress from simultaneous selection for milk and beef traits with the difference in degrees of emphasis, along with estimated changes in total protein production and economic values, are discussed by Calo et al (1973b). a DPT bulls first milk production proof correlated with own EBV for DG/100.…”

“…While this study indicates substantial response could be expected in selection for beef traits, the feasibility of incorporating selection for beef production into the existing dairy herd improvement program would depend on the nature of genetic relationships between milk and beef traits among Holstein-Friesians. The economic values for meat and milk will be of major concern to dairymen (Calo et al, 1973b).…”

Estimating a Genetic Covariance from Least Squares Solutions

“…Lab, USDA, from different animals; i.e., no animal has both traits measured (1). The similarity of these situations lies in the fact that the "errors" associated with records are uncorrelated.…”