J. G. Rowell

Comparison of dry and wet feeding of growing pigs

A co-ordinated trial has been carried out at eighteen centres to compare the following amounts and methods of providing water to growing pigs: (1) water in the feed in the ratio of 2½: 1; (2) water in the feed in the ratio of 4:1; (3) dry feeding with water available separately ad lib .; (4) water in the feed in the ratio of 1½: 1 and also available separately ad lib . Pigs on dry feeding had substantially worse growth rate and feed conversion; carcass lengths were slightly smaller and eye muscles slightly wider. Fat measurements were not significantly affected.

Counting blood cells of chickens

1. Six methods of diluting chickens blood prior to counting erythrocytes and leucocytes in haemacytometers have been studied. No difficulty is found in recognizing erythrocytes. The most satisfactory method of counting leucocytes was the method described by Natt & Herrick (1952) in which the diluent contains methyl violet. Formulae are given which enable standard errors of estimates to be calculated. 2. Three methods of staining blood smears for the differentiation of the various leucocytes have been studied. The method using Leishmans stain appeared to result in good differentiation and was simple to use. However, an experiment to study sampling errors has shown that there may be considerable differences between observers in the percentages of lymphocytes and heterophils when the latter are high, showing that the estimates of these quantities may be biassed. These differences may have been caused by a tendency for heterophils to concentrate to the edges of the smears and for the observers to select different fields for their counts. 3. Although blood counts varied only slightly during the day, there were considerable differences from day to day. The average erythrocyte count for ten chickens fluctuated between about 2·9 and 3·5 millions per mm. 3 during the first 3 weeks after hatching and was more steady for the next 4 weeks at about 2·9 millions per mm. 3 . The average leucocyte count rose from about 10,000 to 35,000 per mm. 3 during the first 7 weeks of life, the rate of increase being greatest when the chickens were youngest; the rise was mainly due to a rise in the number of lymphocytes. 4. There were also considerable differences in blood counts between chickens even though environmental and genetic conditions were standardized as far as possible.

Comparison of meal and pellets for growing pigs fed either in troughs or off the floor

A co-ordinated trial has been carried out with fattening pigs at nineteen centres to compare the effects of the following methods of preparing and presenting the feed: (1) meal fed in the trough; (2) cubes fed in the trough; (3) meal fed off the floor; (4) cubes fed off the floor. Pigs fed meal off the floor had substantially worse growth rate and feed conversion than pigs on any of the other three treatments, probably because of feed wastage. With trough feeding, pigs fed cubes had slightly better growth rate and feed conversion than pigs fed meal. When the feed was given as cubes, there was little to choose between trough feeding and feeding off the floor. Faster growing pigs were slightly fatter and had slightly smaller eye muscles.

A comparison of feeding growing pigs once or twice daily.

1. A co-ordinated trial has been carried out at 17 centres to compare the effects on performance and carcass quality of feeding growing pigs once or twice daily. 2. No significant differences were found between growth rate, efficiency of food conversion or length of pigs on the two treatments. 3. Killing out percentage was on average 0·92% worse for the pigs fed once daily, a significant effect, probably because the pigs on the two treatments received different amounts of food at the last feed before slaughter.

A comparison of wheat and fine wheat offal in the rations of fattening pigs

1. A co-ordinated trial has been carried out at twenty-two centres to compare the value of wheat, crushed or ground, with that of fine wheat offal (weatings) when fed in equal amounts in the rations of growing pigs. 2. Pigs fed the wheat rations grew faster (8·7% improvement for crushed wheat, 6·3% for ground), had. more efficient food conversion (9·0 and 6·5%) and yielded heavier carcasses for a given final live weight (1·4 and 1·3%) than pigs fed weatings but were fatter at the shoulder (5·6 and 7·5%) and the loin (11·2 and 13·1%); all these effects were highly significant. Differences in length of carcass were not significant. 3. Improvements in growth rate and food conversion were significantly greater with crushed wheat than with ground wheat. None of the other differences between crushed wheat and ground wheat was significant. 4. An economic appraisal has been made which shows that, on the basis of certain assumptions, the feeding of wheat would have resulted in higher profit per year than the feeding of weatings under the price structure and system of grading prevailing during the period of the experiment. 5. Changes in the price structure (average price of bacon pigs, differentials between grades and cost of wheat and weatings), in the average quality of the carcasses (length of the carcass and fat at the shoulder and loin) and in the size of treatment effects on food conversion, all have a substantial effect on relative profits. The appraisal suggests, however, that feeding wheat would be more profitable than feeding weatings when the above changes were extremely severe.