Weaning of pigs: exocrine pancreas sectretion and the influence of preweaning housing and postweaning strategic feeding.
1997
Rantzer D.
The aim of this thesis was to add to the knowledge about the effects of the weaning process on pigs and to give practical solutions for reducing postweaning problems. Studies on the influence of different preweaning housing systems and a special feeding regime post weaning were included. Both pigs under production conditions, and catheterized pigs for collection of pancreatic juice were studied. Beside evaluating production and health, special interest was focused on the development of haemolytic Escherichia coli (E. coli) in the intestines; on immunoreactive cationic trypsin (IRCT), a possible indicator of pancreatic function, in blood plasma; and on exocrine pancreas function. Great changes in the pancreatic exocrine secretion took place during the first 5 days postweaning. The volume and the amounts of protein and trypsin secreted increased significantly. The number of haemolytic E. coli in the duodenum also increased during this period, and the proliferation appeared to begin in the ileum. The proportion of pigs with haemolytic E. coli dominating the rectal swab aerobic bacterial flora peaked at about day 7 postweaning and then decreased again. IRCT in the blood plasma started to increase at about 3 weeks of age, and then continued to rise throughout the nine weeks studied. Indications of correlations between plasma IRCT and pancreatic trypsin output or concentration were found. A strategic feed restriction for the pigs during days 3-8 post weaning reduced the amounts of diarrhoea and the proliferation of haemolytic E. coli in the intestines, without these problems occurring when ad lib feeding was resumed, suggesting the development of intestinal immunity. Feed intake and weight gain of the pigs were reduced during the restrictive period. A sow-controlled preweaning housing system decreased the pigs' contact with the sow and the number of sucklings later in lactation, but increased creep feed consumption. The enriched environment of a group housing system for lactating sows and their litters did not increase creep feed consumption or pig performance before weaning. Neither of the preweaning housing systems appeared to prepare the pigs better for weaning, since pig performance and health was not improved post weaning.
显示更多 [+] 显示较少 [-]