I. Pigs were weaned from the sow at 2 d of age and reared on a diet of cow's milk supplemented with vitamin D, and antibiotics. The effects of four levels and two frequencies of feeding, and the temperature of the environment were studied in relation to the performance of the pigs and the digestion of the milk protein. Pigs fed at the two lower levels receivedadiet of cow's milk, but at the two higher levels cow's milk was spray-dried and reconstituted to 20 % total solids. A comparison was also made between cow's milk and spray-dried reconstituted milk, both fed hourly with 12.5 % total solids. The pigs were slaughtered at 28 d of age. 2.No differences in the nutritive value or digestion of the milk protein were found when cow's milk and reconstituted milk were fed with a total solids content of 12.5 yo.3. Increasing the level of feeding resulted in a faster growth rate, and some deterioration in the feed conversion efficiency. The growth rate of the pigs from 2 to 28 d of age when fed at a high level greatly exceeded that of sucking pigs reared on the sow. The retention of the dietary nitrogen also improved with increased feed intake. A highly significant inverse linear correlation of N retention with age was found at all levels of feeding. The milk protein was efficiently digested at all levels of feeding. 4.The mortality rate was very low but there appeared to be some association of losses with a high level of feeding during the first few days of life.5. Feeding hourly compared with feeding twice daily improved the feed conversion efficiency, although the effect on growth rate and N retention was small. The retention of digesta in the stomach appeared to be an important factor in the regulation of the amount of digesta in the small intestine and in the maintenance of digestive efficiency. The stomachs of pigs fed twice daily contained considerably greater amounts of digesta than those of pigs fed at hourly intervals. There was little difference in the amount and composition of digesta in the small intestine and caecum at either frequency of feeding.6. No differences were found in the performance of the pigs, N retention or the efficiency of digestion of the milk protein when the environmental temperature was maintained either at zoo throughout the experiment, or at 30' gradually reducing to zoo during the first 14 d.Artificial rearing methods which involve removal of the pigs from the sow soon after birth and rearing them on milk substitutes could have the following advantages over the conventional rearing on the sow: reduction of losses of pigs through control of environment, improvement in their growth rate by making available more nourishment than that supplied by the sow, elimination of lactation and shortening of the reproductive cycle of the sow, thus increasing her productivity by enabling her to produce a larger number of pigs per year. The economic advantages of a successful artificial rearing routine could be considerable.Earlier work at Shinfield provided basic information on the qualitative and q...

Some characteristics of the association between lactic acid bacteria and pig squamous epithelial cells were studied. Strains from several sources were tested for adhesion in vitro but only those from pigs and chickens attached. The adhesion rate of pig isolates was very variable and, of the isolates tested, strains of Lactobacillus fermentum and Streptococcus salivarius attached in largest numbers. These strains were selected for further study. They did not attach to columnar epithelial cells from the small and large intestine. Adhesion was reduced by sodium periodate or protease. Both strains had a microcapsule with fibrils which stained with ruthenium red. The adhesive bond between lactobacilli and squamous tissue was strong enough to resist washing 50 times but there was a persistent release of bacteria during the washing process. When the strains of both species or of L. fermentum alone were fed to artificially reared pigs there was a statistically significant reduction in the numbers of Escherichia coli in the stomach.

1. The butterfat in a whole-milk diet was replaced by either beef tallow, coconut oil or soya-bean oil. The diets contained 280 g fat and 720 g dried skim milk per kg and were supplemented with vitamins A, D, E and K.2. These diets were offered as a milk, containing 200 g solids/Kg, to pigs weaned at 2 d of age during a 26 d experiment. The pigs were fed at hourly intervals to a scale based on live weight (scale E).3. The performance of the pigs and the apparent digestibility of the dietary fats indicated that soya-bean oil was equal to butterfat. Butterfat was slightly superior to coconut oil and markedly superior to beef tallow.4. The amount and composition of the fatty acids were studied in the proximal, mid and distal portions of the small intestine. When the beef tallow diet was given there was an increased amount of total fatty acids in the digesta of the small intestine, mainly in the distal portion. The digesta contained the smallest quantity of fatty acids when the soya-bean oil diet was given. The fatty acid composition of the digesta indicated that the short- and medium chain fatty acids from all the diets were well utilized, but an increasing proportion of stearic acid occurred in the distal portion of the small intestine. The interpretation of changes in fatty acid composition in the digesta in relation to absorption is discussed.

The gastrointestinal microflora and gastric physiology of piglets weaned at 2 days was compared with that of piglets allowed to continue sucking the sow. Although there was a significantly higher count of Escherichia coli in the stomach, duodenum, and jejunum of the early-weaned compared with sow-reared pigs, these differences were not detectable in samples from the ileum. There were no quantitative differences in lactobacilli and in streptococci between the two treatments. Lactobacillus fermentum, L. acidophilus, Streptococcus salivarius, S. bovis , and related biotypes were isolated from both groups of pigs. L. fermentum and S. salivarius were isolated more frequently from sow-reared piglets. The weight of digesta in the stomach was greater in weaned than in sucking pigs and was even greater in scouring weaned pigs, suggesting that in scouring pigs there may be gastric stasis. The gastric pH was higher in the weaned pigs at 4 days of age, but gradually decreased up to 10 days, during which time the lactic acid concentration rose. In weaned pigs there was a highly significant negative correlation between pH and lactic acid concentration in the stomach digesta, and also a positive correlation between pH and number of E. coli. These correlations suggest that lactic acid, from bacterial fermentation, is the major component in the regulation of gastric pH in weaned pigs. Three of twenty sucking pigs, but none of the weaned pigs, were secreting HCl (chloride concentration > 3 mg/g, pH < 3.5). In sucking pigs there was an inverse relationship between the chloride and lactic acid concentrations in the digesta. In weaned scouring pigs there was a nonsignificant increase in pepsin concentration in the stomach tissue. There was a threefold increase in the total proteolytic activity of the stomach tissue.

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