Maternal "imprinting" in Goats.

Some years ago Collias1 reported a study on maternal-filial bonds in goats in which he suggested that events transpiring during a brief post partum period were particularly important. As part of our studies of the ontogenesis of social behavior, we have sought to subject the putative importance of this period to a further analysis, with special attention to its precise boundaries (if any) and the nature of the stimuli to which the goats were responding. Methods.-Our Toggenburg goat does were allowed to choose their own birth sites, either within one of the barns or the pastures where they normally lived. One group of does ("immediate separation" group) was deprived of all its young from the instant of birth: the kids were wrapped in cloth upon emergence and carried away before any licking or nuzzling by the mother could occur. The separation was occasionally even completed without the amnion having been ruptured. In a second group of does ("prior contact" group), each animal was permitted 5 minutes with one of its young (if more than one was born, it was usually the firstborn that was permitted contact) before an ensuing separation. The 5-minute interval was timed from the first nuzzling or licking of the young and was interrupted during the birth process if the goat gave birth to another kid. Thus, the total exposure period ranged up to 10 minutes (but never more, and rarely over 6 minutes). The periods of separation for both groups were 1, 2, or 3 hours, after which the young were returned, one at a time, to their mothers. The responses of the mothers to their own young were tested singly. Where possible, a test was made with comparably aged young (e.g., within 72 hr) of another doe. Detailed notes of the reciprocal responses of mother and young were made by an observer familiar with the goats, who also was not alarming to them. The responses were evaluated as indicating acceptance (+) if nursing or nonrepulsed nursing efforts occurred within 10 minutes after introduction of the kid. Rejection (0) was defined as active repulsion (butting or biting) of the kid by the mother, or a refusal by the mother to maintain the appropriate nursing orientation. The more usual pattern for "rejecting" mothers involved their licking the kid until it touched her flank or udder, then turning abruptly away or else biting the kid at the base of its tail. We always checked the condition of the udder on these occasions to be certain it was not painfully engorged or infected. For the behavior of unmolested controls, refer to Collias.1 Our normal controls behaved identically to his. Results.-Table 1 compares the effects on subsequent behavior of the immediate separation and the 5-minute prior contact. The following conclusions are evident: (1) There is no discernible difference in the behavior of primipara and multipara. (2) Of the "immediate separation" animals, 12/14 rejected their kids, compared with 2/15 of the "prior contact" group. The confidence limits of these proportions do not overlap, even at the 0.99 level. (Two other animals of the first group died in labor.)