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Feeding Pigs: Divergence of Behavioural and Physiological Requirements

A.B. LAWRENCE 1, M.C. APPLEBY 1 and H.A. MACLEOD 2

~Edinburgh School of Agriculture, West Mains Road, Edinburgh (Gt. Britain) 2Department of Psychology, University of Edinburgh, George Square, Edinburgh (Gt. Britain)

ABSTRACT

The consequences of commercial feeding regimes for behaviour and welfare have rarely been considered. Recent work at Edinburgh suggests that hunger may be a source of stress for pigs on restricted food allowances. The present study used operant conditioning to measure the hunger of pigs offered low food levels typical of certain commercial conditions. The ad libitum intake of 6 Large White × Landrace boars was measured. The boars were then restricted to 0.8, 0.6 and 0.4 of their ad libitum intake in a Latin Square design. Subsequently, they were offered their previously measured ad libitum intake (Treatment 1.0). Hunger was measured on all the above food levels by conditioning boars in a separate room to press a panel to receive 7-g rewards of food. Rewards were contingent on 10 panel presses. Work (number of panel presses) was recorded in 20-min tests before feeding, immediately post-feeding and 5 h post-feeding.

Work rate was strongly affected by food allowance (F= 30.96; df, 105.54; P < 0.001 ) and time of day (P< 0.001 ). There was no difference in work between treatments before feeding. Treatments 1.0 and 0.8 depressed work immediately post-feeding (P < 0.01 ) and Treatment 1.0 also 5 h post- feeding (P < 0.001 ). Work rates on treatments 0.6 and 0.4 did not vary from one another or with time of day. These results indicate that restricting pigs to low food allowances results in a high level of hunger throughout the day. Commercial food allowances for pregnant sows and boars, whilst meeting production needs, do not satisfy motivation. The resulting hunger may act as a major source of stress under certain housing conditions.

Behaviour of Group-housed Sows Fed Individually Using a Computer-controlled Feeding System

D. RANTZER, ANNE-CHARLOTTE OLSSON, M. ANDERSSON and J. SVENDSEN

Swedish University of Agricultural Sciences, Box 624, S-220 06 Lurid (Sweden)