ferent breed makeups. It is widely used in commercial beef production because of the benefits it has to offer cow-calf producers. Improvements in efficiency can be dramatic if appropriate breed combinations are used. Crossbreeding does not eliminate the need for outstanding purebred cattle since efficient systems require well characterized, superior purebred cattle. Crossbreeding in beef cattle...

Since the influential work of Dickerson (1969), there has been considerable discussion of design of crossbreeding experiments, but little detailed treatment of optimisation. Recently, Cunningham and Connolly (1989) and Soelkner and James (1990) have discussed this question, but have used different optimality criteria. Connolly and Cunningham used the sum of sampling variances of estimators, whi...

Quality, quantity, and cost of feed resources available for beef production vary from one region of the country to another and within regions, depending upon climatic factors and natural resources available in specific production situations. Diversity among breeds can be exploited by crossbreeding to optimize performance levels and to match genetic resources with the climatic environment, feed ...

Changes in the Mean and Variance Under Inbreeding Inbreeding Inbreeding (mating of related individuals) often results in a change in the mean of a trait compared with its value in a random-mating population. Its importance is that inbreeding is generally harmful and reduces fitness. In particular, inbreeding often causes a reduction of the mean value for quantitative traits associated with repr...

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J. Anim. Sci. Vol. 88, E-Suppl. 2/J. Dairy Sci. Vol. 93, E-Suppl. 1/Poult. Sci. Vol. 89, E-Suppl. 1 430 Application of a crossbred model reveals additional genetic variation in reproduction traits of commercial females. S. Bloemhof*1,2, E. F. Knol1, A. Kause2, and I. Misztal3, 1IPG, Institute for Pig Genetics B.V., Beuningen, the Netherlands, 2Animal Breeding and Genomics Centre, Wageningen Uni...