Behaviour and growth of piglets weaned at 5 and 7 weeks of age in an organic environment

Abstract: Weaning in pig production today is an abrupt change at an early age for the piglets. Problems that can be associated with weaning is behavioral and health problems for the young pig. Such problems can be impaired intestinal functions, reduced weight gain, and increased stress syndromes. The current law concerning weaning age for pig production in Sweden allows weaning at an age of four weeks, yet the common weaning age is at five weeks of age. According to the organic rules of KRAV, the Swedish certification organization, weaning is not allowed before seven weeks of age. The aim of this study was to investigate behaviour and growth in piglets weaned at five or seven weeks of age in an environment comparable with organic pig production. The sows farrowed in farrowing pens and two weeks after birth the piglets and their mother were moved to a loose housing system with deep straw bed. The sows were held in groups of 4-5 sows with their litters. The piglets were held in the same groups during the entire study. They were weighed at birth, four days of age, and once a week from two weeks up to nine weeks of age. Behavioural observations were made in four groups once a week from five up to eight weeks of age. Activity and social behaviour were observed on all piglets in the groups. The first two groups were weaned at seven weeks of age containing five and four litters, with 48 respectively 47 piglets. In the last two groups the piglets were weaned at five weeks of age. These groups contained four litters, with 43 and 45 piglets. The weights differed between the two weaning age groups. The piglets weaned at seven weeks grew better than the piglets weaned at five weeks. No differences were found in weights before five weeks of age. There were significant differences in growth rate between five to eight weeks of age. The piglets weaned at seven weeks had a higher growth rate than the piglets weaned at five weeks during these weeks. There was a significant difference in weight variation within litters between the two weaning age groups. The piglets weaned at seven weeks varied less than the piglets weaned at five weeks. There was a difference in belly nosing behaviour at seven and eight week of age; the piglets weaned at five weeks performed more belly nosing behaviour than other piglets. The piglets were most passive the day after weaning regardless of weaning age. They followed similar patterns in activity within pen and seemed to function as one big social group.