THE HERITABILITY OF THE TRAIT FEAR OF HUMANS AND THE ASSOCIATION BETWEEN THIS TRAIT AND SUBSEQUENT REPRODUCTIVE-PERFORMANCE OF GILTS

The main objective of this study was to obtain an accurate estimate of the heritability of the trait fear of humans in gilts. At 25-30 weeks of age, the approach behaviour of 425 gilts to a stationary experimenter in a standard test was studied in order to measure the pig's level of fear of humans. The 425 gilts were from a total of 76 sires and estimates of genetic variance were obtained by restricted maximum likelihood methods. The variable, the time to physically interact with the experimenter, was found to be moderately heritable (heritability±s.e. of 0.376±0.19). The association between the level of fear of humans and subsequent reproductive performance was also studied. There was a trend that closely approached significance at the 5% probability level for a lower proportion of gilts that failed to interact with the experimenter in the standard test (high level of fear category) to be mated (0.88 vs. 0.93 for gilts that interacted). In addition, the gilts in the high level of fear category had a lower number of matings (2.31 vs. 2.51, P<0.05), probably because of this apparent difference in mating rate. There were no differences in either pregnancy rate or litter size of gilts in the two fear categories. The need to conduct research on the within-farm association between fear and reproduction at farms where fear and the behaviour of the stockperson are regularly monitored is discussed. © 1990.