Some genetic and non-genetic effects on the first oestrus and pregnancy rate of beef heifers


C.A. Morris, R.L. Baker and G.L. Bennett

Ruakura Animal Research Station, Ministry of Agriculture and Fisheries, Hamilton

Proceedings of the New Zealand Society of Animalshort scrotum rams were b growth and feed consumption and makes economic assessments on export carcass grading returns is described. It simulates a flock of lambs of specified weight and sex and then, using relationships between live weight, carcass weight and GR, derives grading profiles for various drafting strategies.

The option of drafting on the basis of live weight has been compared with options based on GR estimates of high, average and poor accuracy.

These drafting policies were evaluated on the basis of several alternative fixed endpoints including total feed consumption, carcass weight and carcass value. Generally results obtained when drafting on GR were better than those based on live weight alone when GR was measured with high accuracy and when carcass weights were high.

This model could be useful in making a wide range of evaluations and comparisons other than those reported.

Keywords: NZSAPAB; Lamb drafting; simulation model; fatness; carcass grading; GR measurement; live weight


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Last Updated 18-03-1997