Weaning of pigs

Post weaning diarrhoea is a common problem in pig production. The causes are multifactorial, but most often associated with infection of pathogenic strains of Escherichia coli in the small intestine. The aim of these studies was to investigate some of the physiological and managemental factors involved at weaning. The lectin phytohaemagglutinin (PHA) is known for its growth promoting properties from studies on suckling rats and pigs. The hypothesis was that enteral exposure would induce precocious maturation, leading to a gastrointestinal (GI) tract better prepared for weaning. PHA-treated pigs grew slower during the treatment week before weaning, and in one of the two studies presented here; the PHA-treated pigs had a higher body weight (BW) gain than the control pigs in the week immediately following weaning. PHA treatment resulted in lower diarrhoea scores, a more beneficial feeding pattern and a tendency to greater feed intake. Effects on physiological parameters were shown, with a lower uptake of marker molecules, and a more adult disaccharidase pattern in PHA-treated pigs. No differences were found regarding immunological status, weight and length of the intestinal organs, the pancreatic enzyme activities or feed conversion ratio. It was investigated how pigs of different relative size (small, medium and large) in a group of 10 pigs were affected by receiving feed from a feed dispenser with 2 feeding places per pen, or from a trough where all pigs could eat at the same time. Also, comparisons were made between keeping pigs as unmixed litters staying in their farrowing pen after weaning, or mixing and moving them to a new pen on the day of weaning. Trough feeding resulted in lower diarrhoea scores for the small and large pigs, and higher scores for the medium pigs. All size categories had longer feeding bouts when fed at a trough, and longer total feeding times on day 1 (small pigs) and 5 (large pigs) after weaning. The feed conversion ratio was lower during the second week after weaning for the pigs fed from feed dispensers. The mixing and moving procedure resulted in lower BW gain compared to that of pigs weaned as whole litters, which was most pronounced in small pigs. Mixed and moved pigs also had lower feed intakes and higher diarrhoea scores (small and large pigs)