Artificial rearing of pigs

Abstract

1. The requirement of the artificially-reared pig for crude protein (nitrogen × 6.38; CP) was estimated between 2 and 28 d of age. The pigs were given one of five diets, each containing 270 g soya-bean oil/kg and either dried skim-milk and dried whey in different proportions to supply 150, 180, 210 or 240 g CP/kg, or dried skim-milk alone which supplied 270 g CP/kg. The energy content of the diets was approximately 22 MJ digestible energy/kg.2. The diets were obtained as spray-dried powders, reconstituted in water, and fed as a liquid containing 200 g DM/l. The pigs were fed at hourly intervals to a scale based on live weight.3. N retention (g/d per kg live weight) and the proportion of CP in the carcass indicated a CP requirement of 240 g/kg for pigs from 2–28 d of age.There was no significant difference (P > 005)in performance between levels of dietary CP of 2.10, 240 or 270 g/kg. Although there was no increase in the proportion of CP in the carcass above a dietary CP level of 240 g/kg, a linear reduction in the proportion of lipid occurred as dietary CP level increased from 150 to 270 g/kg. Mortality, which was associated with scouring, was increased when the diet contained less than 210 g CP/kg.4. There was a linear response in N retention to the level of CP in the diet at 7 d of age, whereas at 19 d of age, N retention reached a maximum with 240 g CP/kg diet, suggesting that the CP requirement may be greater during the first week of life.5. Excretion of endogenous N in the urine was found to be 250 mg N/d per kg live-weight^0.75 in pigs between 7 and 19 d of age (20–6.4 kg live weight).