A note on precise tracking of suckling position by piglets

Janko Skok,Dejan Škorjanc

doi:10.7482/0003-9438-57-011

Abstract

Abstract. Piglets establish a relatively stable teat order after the first week of lactation, when each piglet chooses a preferred teat or teat pair where they tend to suckle permanently. The mechanism underlying the choice that leads each piglet to the same suckling position is still not clarified. In the present case study, piglets with different preferred suckling positions (anterior, posterior) were transferred to a foster sow after completion of the regular 4 weeks of lactation by their biological mother. For both sows, which were identical based on parity, litter size and farrowing date, we examined the suckling positions of the experimental piglets. Piglets occupied exactly the same suckling positions on both sows. Thus, piglets precisely track positions on the mammary complex of a sows udder even when previously learned discriminable stimuli have been changed, such as odours, tastes, morphologies (of sows udder or the sow itself), vocalizations, and neighbouring littermates. Our observation indicates that the spatial configuration of the mammary complex, which is determined by two parallel rows of teats arranged in pairs, can hypothetically be proposed as an important cue for piglet suckling orientation. Therefore, additional attention should be given to the exact spatial position of piglets (and vacant positions) on the mammary complex of biological and foster mothers in order to reduce stress from cross-fostering, which is standard practice in contemporary piglet production.

Highlights

Knowledge of pig cognition is of great importance considering the anatomical and developmental similarities between pig and human brain (Lind et al 2007)
During later elongated lactation, the two experimental piglets occupied and remained at the same suckling position on the foster sow as they had occupied on their biological mother (Figure 1)
Whereas in the original litter they mostly used one of the teats in the pair, they always exploited both teats in the occupied teat pair on the foster sow

Summary

Introduction

Knowledge of pig cognition is of great importance considering the anatomical and developmental similarities between pig and human brain (Lind et al 2007). Previous studies have firmly elucidated the spatial learning and memory abilities of both adult and neonatal piglets, their aversive and appetitive learning abilities, sensory capacities, recognition of conspecifics, and other cognitive abilities (see review by Gieling et al 2011) Many of these cognitive abilities in pigs can be proposed to play an important part in neonatal piglets choice of a preferential suckling position (teat or teat pair), and its permanent use during lactation. Successful competitors are rewarded with milk from the obtained teat, and the piglets that miss suckling likely experience hunger To avoid such costly behaviour throughout lactation, piglets learn a position where they have successfully accessed a teat or teat pair and tend to exploit this position persistently. Various factors may contribute to teat preferences (McBride 1963, Rosillon-Warnier & Paquay 1984), such as milk productivity (Jeppesen 1982a), specific odours and tastes of teats (Jeppesen 1982b), proximity to the sows head and vocalizations (Castrén et al 1989, Kasanen & Algers 2002), morphological characteristics of teats (Jeppesen 1982b), or recognition of littermates (Ewbank et al 1974, McLeman et al 2005)

Methods

Results

Conclusion