| dc.description.abstract | Temperament is the response of animals to handling. Research has shown that cattle temperament is associated with productive traits. Locating and understanding the genes associated with temperament could help for selection and genetic improvement. The objectives of this research were to estimate the heritability of cow temperament at parturition, conduct a genome-wide association analysis of cow temperament at the time of parturition, estimate the correspondence of cow temperament at the time of parturition with various measures of cow productive performance, and estimate the correspondence of cow temperament at parturition with temperament measured on the same females when they were weaned. Estimates of heritability for highest temperament scores and of the proportions of temperament scores greater than 1 were 0.23 ± 0.07 and 0.12 ± 0.067, respectively. Within generations, 2-yr-old cows had lower temperament score means than cows in most other age categories. Positive estimates of correlation coefficients of unadjusted temperament with weaning weight per cow exposed (r > 0.249), weaning weight per 454 kg (1,000 lb) cow weight (r > 0.166), birth weight (r > 0.143), weaning weight (r > 0.101), cow weight (r > 0.175) and cow body condition score (r > 0.026) were found. Cows with higher temperament scores also showed higher fertility measures (calving rate (r > 0.173) and weaning rate (r > 0.229). Although not large in magnitude, they provide evidence that counters other descriptions of relationships of favorable temperament with increased productivity. There were insufficient numbers of cows to estimate genetic correlations between temperament traits and productivity traits. Genome wide association test results associated SNP on BTA 4 and 11 for highest temperament scores; and BTA 14 for proportions of temperament scores greater than 1. | |
