SOME GENETIC-FACTORS AFFECTING TEMPERAMENT IN BOS-TAURUS CATTLE

Temperament scores were recorded by two operators on a herd of Bos tau rus beef cattle, including Angus and Hereford controls and various cro ssbred groups. The herd consisted of 765 cows, 653 calves at foot (ave rage age 2 months), and 250 yearling heifers. Recording of temperament in the yards was carried out at weighing time in November 1982 using a 1-8 scale, and immediately afterwards when the herd was drafted for natural mating using a 1-6 scale, with higher scores indicating more d ifficulty experienced by stockmen in carrying out the routine weighing and drafting operations. In addition, a calving temperament score was recorded on 2121 cows calving in 1981-90 using a 0-5 scale. Both scor es in the yards differed significantly among cow breed groups (P < 0.0 01). The range of means was 1.73 units (1.86 phenotypic standard devia tions: sigma) or the weighing score (Score 1) and 1.57 units (1.29sigm a) for the drafting score (Score 2). Corresponding data for yearling b reed groups were 1.11sigma for Score 1 (P < 0.001) and 0.49sigma for S core 2 (not significant), and for calf breed groups 0.99sigma for Scor e 1 (P < 0.001) and 0.90sigma for Score 2 (P < 0.01). The heritability for average cow score in the yards (untransformed scale) was 0.22 +/- 0.15 (based on 176 sires), for average yearling score was 0.32 +/- 0. 24 (47 sire groups), and for average calf score was 0.23 +/- 0.12 (53 different sire groups). Transforming data to a logarithmic scale made little difference to these estimates. Cow's calving temperament score had a heritability of 0.09 +/- 0.03 (486 sires) and a repeatability of 0.20 +/- 0.02. The correlation of average weighing/drafting scores fo r cow-calf pairs was 0.27, or 0.14 after adjustment for breed group. C orrelations among breed groups were 0.49 for Scores 1 and 2 from cows, 0.65 for mean scores from cows and yearlings, 0.79 for mean scores fr om yearlings and calves, and 0.54 for mean scores from cows and calves . It was concluded that there were generally significant differences a mong breeds for temperament scores, and that breeds ranked similarly o ver the various age groups. Cow differences within breed were repeatab le, but heritable effects were generally small.