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Separate experiments were conducted in 2 zebu-derived herds grazed at pasture in the dry tropics of Central Queensland, to determine genetic and environmental effects on At Duckponds, temperament of crossbreed steers and heifers from 2 calf crops was assessed using an objective flight speed score and 2 subjective scores (a visual flight speed score and a crush score) to determine whether the subjective tests were useful as selection criteria for on-farm selection programs. At Belmont, temperament of bull and heifer calves from 7 calf crops was measured by recording objective flight speed scores of individual animals at weaning (6 months), 12 months, and 18 months. At Duckponds, heritabilities of average objective flight speed, visual flight speed, and crush scores were 0.35, 0.08, and 0.30, respectively. Phenotypic and genetic correlations between the different measures of temperament were moderate to low. Based on low correlations and re-ranking of fixed effect classes that occurred between subjective tests, it was concluded the subjective tests were not sufficiently correlated with the objective measure to justify their use. The objective flight speed score is recommended as the test of choice for use in breeding programs using |
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