Nipple preference and contests in suckling kittens of the domestic cat are unrelated to presumed nipple quality

Abstract

We studied the development of suckling behavior and weight gain in 11 litters (52 kittens) of free-ranging domestic cats until postnatal day 28 just before the start of weaning. In six of these litters, we also recorded milk intake and contests for access to nipples. Already within 12 hr of birth kittens showed a preference for posterior nipples, and by postnatal day 3 each had developed a preference for particular nipples. In fact, 86% of kittens used one particular nipple most often, and even when the mother changed the side she lay on to nurse. Contests for access to nipples occurred throughout the study period at an average rate of one to two contests per kitten per hour of nursing. Contrary to suggestions in the literature that kittens compete for more productive nipples, we found no relation between kittens' use of particular nipples and their weight gain, milk intake, or involvement in contests during suckling. We suggest that kittens' preference for posterior nipples as well as their establishment of an individual "teat order" might function to optimize the number of nipples remaining productive across lactation, and to reduce energetically costly scrambles and potentially injurious contests among littermates.

Olfactory guidance of nipple attachment and suckling in kittens of the domestic cat: Inborn and learned responses

“…Kittens that could not be readily distinguished by coat color were marked on the head, nape or back with white correcting fluid in the case of dark kittens, and with gentian violet spray in the case of white or ginger kittens. As reported previously (Hudson et al, 2009), this did not appear to affect the behavior of either mothers or young, and the weight gain of marked kittens did not differ from that of their unmarked littermates.…”

“…They were fed daily dried and canned commercial cat food and fresh meat and fish. Milk, water, dried food and litter Developmental Psychobiology trays were always available, and the females were free to leave the house at will (Hudson et al, 2009). Each female served as a test stimulus in multiple experiments (see below), and the response of kittens to the ventrum of stimulus females was tested when the kittens were between 0 (day of birth) and 24 days old, that is, before and after eye opening and before the start of weaning at about 1 month of age.…”

“…Based on previous observations (Ewer, 1959(Ewer, , 1961Hudson et al, 2009), we hypothesized that kittens would use both inborn and postnataly learned olfactory cues to locate nipples and suckle, and we conducted three kinds of experiments to test the following predictions: (1) that kittens will respond with nipple-search and suckling behavior from birth (i.e., without postnatal experience) to the ventrum of lactating but not to the ventrum of nonlactating females; (2) based on studies in the rabbit mentioned above, that the strength of the kittens' response will depend on females' reproductive state; and (3) that kittens tested on the ventrum of lactating females other than their mother will not attach preferentially to nipples corresponding in location to their particular nipples on their mother.…”

“…The agreement of these findings with earlier reports (Ewer, 1959(Ewer, , 1961Rosenblatt, 1962Rosenblatt, , 1971Rosenblatt, , 1972Rosenblatt, , 1983; recent review in Mermet, Coureaud, McGrane, & Schaal, 2008), suggests the robust nature of this behavior and the ready opportunity it provides to experimentally study sensory and cognitive mechanisms underlying the organization of suckling behavior in these altricial young. Given that kittens only start to open their eyes during the second postnatal week, it seems likely that olfactory cues on the mother's ventrum are important in stimulating nipple-search behavior and in eliciting nipple attachment (Ewer, 1959(Ewer, , 1961Hudson et al, 2009;Rosenblatt, 1971Rosenblatt, , 1972Rosenblatt, , 1983.…”

“…In a recent study of suckling behavior in the domestic cat (Hudson, Raihani, González, Bautista, & Distel, 2009), we reported that kittens nuzzle the mother's ventrum and attach to nipples unaided by her within minutes of birth, that at first they attach to any nipple but within hours mainly use nipples in the more posterior rows, and that by postnatal day 3 they have developed a well-defined ''teat order'' in which each kitten mainly uses one or sometimes two particular nipples regardless of the side the mother lies on to nurse. The agreement of these findings with earlier reports (Ewer, 1959(Ewer, , 1961Rosenblatt, 1962Rosenblatt, , 1971Rosenblatt, , 1972Rosenblatt, , 1983; recent review in Mermet, Coureaud, McGrane, & Schaal, 2008), suggests the robust nature of this behavior and the ready opportunity it provides to experimentally study sensory and cognitive mechanisms underlying the organization of suckling behavior in these altricial young.…”