Intermittent suckling during an extended lactation period: Effects on piglet behavior

¹ Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands
² Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, P.O. Box 336, 6700 AH Wageningen, The Netherlands

^* To whom correspondence should be addressed. E-mail: m.berkeveld{at}vet.uu.nl.

	Abstract

The objectives of the present study were to determine how intermittent suckling (IS) affects nursing behavior, litter activity, and general behavioral patterns during lactation and whether IS during an extended lactation period results in behavioral patterns associated with piglet distress. Intermittent suckling was applied either with 6-h separation intervals (IS6) or 12-h separation intervals (IS12), and compared to conventional treatment (CT). In CT (n = 17 litters), sows were continuously present until weaning (d 21, d 0 = farrowing). In both IS6 and IS12, sows were separated from their litter for 12 h/d, starting at d 14 and lasting until weaning (d 43 ± 1 d). In IS6, litters (n = 14) and sows were separated from 0800 to 1400 and from 2000 to 0200; in IS12 litters (n = 14) between 0800 and 2000. In IS litters, the activity pattern over the 24-h cycle was markedly changed by IS; litter activity was lower (P < 0.001) during absence and greater (P < 0.001) during presence of the sow compared to the unweaned CT litters. Moreover, both total nursing frequency (P < 0.001) and the percentage (P < 0.002) of successful nursings were reduced by IS. Although total nursing frequency was greater in IS6 compared to IS12 (on d 21 and d 28), no differences in frequency of successful nursings existed between IS6 and IS12 from d 14 onwards. Eating behavior was increased shortly after onset of IS (d 17) in both IS6 (P = 0.059) and IS12 (P < 0.001) compared to the unweaned CT litters. The IS12 litters showed more eating behavior compared to IS6 and their explorative behavior increased in time (P < 0.001), whereas IS6 showed more nursing behavior. Aggressive or manipulative behavior of both IS treatments was similar compared to the unweaned CT treatment, and remained relatively unaltered with time in IS12 and IS6. Weaning of CT resulted in more manipulative (P < 0.001) and aggressive (P = 0.004) behavior compared to preweaning values. Intermittent suckling may contribute to adaptation to the postweaning state, by stimulating eating behavior, without causing obvious behavioral distress.

Key Words: activity, extended lactation, pig, intermittent suckling, nursing, piglet behavior