Effects of early handling on heifers' subsequent reactivity to humans and to unfamiliar situations

The influence of early handling on the behavioural and physiological responses of Friesian heifers to unfamiliar situations and human manipulation was studied. Forty abimals were used. The animals were reared in 4 groups of 10, under standard artificial husbandry conditions. Animals of one group (control animals) were handled only in respect of the demands of normal husbandry. Experimental animals were subjected to additional handling, which consisted of brushing twice a day and leading with a halter. All handled animals received the same amount of handling (30 days) but at different periods in life: 3 days/week from 0 to 3 months of age (Group 0–3); 3 days/week from 6 to 9 months of age (Group 6–9); or 3 days/month from 0 to 9 months of age (Group –9).

When the animals were 15 months old, each heifer, from each treatment group, was tested individually and once only in a set of behavioural tests designed to investigate fearfulness (in the presence or absence of human contact) and the ease with which the animal could be handled.

Animals from Group 0–9, and to a lesser extent those from Group 6–9, were less reactive than controls in tests involving the presence of a human. However, in most cases Group 0–3 animals did not differ significantly from controls. Thus, it would appear that only prolonged handling during early life substantially influences man-animal relationships.

In the fear-eliciting tests, which did not involve human contact, only the responses of Group 0–9 animals differed significantly from those of the controls. It is suggested that temporary prolonged handling influences the expression of fear responses in heifers.