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SUMMARYThree trials have been made with growing pigs to measure the digestibility of four samples of wheat offal. Two samples were measured at the levels of 0, 20, 40 and 60% of the diet and two samples were measured at the levels of 0 and 60% of the diet. The offal replaced equal quantities of glucose in the diets and no attempt was made to equalize nutrient levels between diets.Apparent digestibility coefficients of the diets declined with increasing dietary wheat offal content, but the digestibility of wheat offal did not change with level of inclusion. No differences in digestibility occurred between offals from hard and soft wheats, apart from a low N digestibility in one sample of soft wheat offal. The average digestible energy and TDN contents were 2810 kcal/kg and 63·1 for samples of offal containing 12·5% moisture.

An experiment, involving 68 female pigs, was undertaken to measure the effects of two diets differing in protein content, and of two patterns of feeding. The animals were housed in an enclosed building. The experiment extended through several parities; culled sows were replaced by gilts during the experiment, the whole course of which lasted 5 years.The diets were given at the rate of 1-8 or 2-3 kg per day throughout gestation, but the rate was reversed during the 5-week lactation so that, for litters of eight to nine pigs sows in each treatment group received the same quantity of food per parity. As a result of unsatisfactory performance, dietary composition was changed after 2 years so that for the last 3 years the digestible energy contents were higher.Treatments significantly influenced gestation live-weight gain, lactation weight loss and gestation backfat gain. The lower rate of gestation feeding was associated with low or negative gestation weight increases after the third to fourth litters, and a greater apparent rate of decline with increasing age in birth and 3-week weight per piglet. The high gestation, low lactation, rates of feeding led to slightly greater litter size and lower weaning weights per pig. A daily intake of 208 g crude protein and 8'3 g lysine appeared to meet the sow's requirements throughout gestation.In the pregnant sow feeding area, winter air temperatures were on average 16 °C below those in the summer, but were rarely below freezing point. Winter backfat gain was lower than, and gestation gain only half that in the summer. Litter size was also greater following summer pregnancies and 3-week weight per pig was greater following winter pregnancies. Independent of litter size, birth and 3-week weight per pig were positively correlated with gestation gain within treatment and season. The apparent positive correlation of litter size at 3 weeks with gestation backfat and weight gain was not found at birth. Litter size at birth was negatively correlated with gestation gain within season. The percentage of fertile matingswas less for matings between 1 September and 31 January. This coincided approximately with the reduced litter size (alive) which occurred following winter gestations.Lactation weight loss and 3-week weight per pig declined with increasing age of sow and the degree of weight loss was unrelated to subsequent litter size.The apparent effect of seasons and treatments on litter size at birth appeared not to be an obvious function of changes in live weight, which were also marked between seasons and treatments, but level of food intake in early gestation may have affected litter size independently. It was concluded that birth weight especially in the older sows, was associated with the rate of food intake in gestation, and possibly also in lactation, and with gestation empty weight gain.

SUMMARYWeaner Hampshire × Landrace × Large White (Hampshire cross) and Landrace × Landrace × Large White (Landrace cross) pigs were given combinations of three diets differing in crude protein content (high: H, low: Land very low: vl). Hampshire cross pigs at 90 kg, both under ad libitum and restricted feeding had greater rates of gain and eye muscle measurements and shorter carcasses than Landrace cross pigs, but were fatter after ad libitum feeding and more efficient food converters after restricted feeding. The HLL treatment led to improved gain and food conversion compared to the LLH or LLL treatment, whereas the LLH treatment led to larger eye muscle measurements. The LvlH treatment led to greater efficiency and eye-muscle area than treatment Lvlvl at 114 kg. An economic analysis was carried out to assess the relative profitability of slaughtering at a range of live weights. Curves were fitted to the data on food intake and live weight. Values were assumed for major costs, and a seven-day interval was allowed between batches of pigs. The calculations indicated that the H diet led to a slight increase in monetary return per pig per day when it was given in the post-weaning period to pigs fed to a scale. Although the Hampshire cross pigs showed a response to the H diet in the finishing period when slaughtered either at 90 or 114 kg, their calculated return was not increased. Ad libitum feeding led to a greater return for heavy but not, on average, for bacon pigs. Maximum return occurred at slaughter between 70 and 115 kg live weight and was only margin-ally greater for restricted baconers at 90 kg than for ad libitum heavy pigs at 110–115 kg. However, return as a percentage of working plus fixed capital was greater for baconers, but the ratio rose throughout the range of hypothetical slaughter weights in both groups. In-clusion of the cost of borrowing money had a negligible effect on the slaughter weight for maximum return with pigs managed in batches.

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1. Six methods of diluting chicken's 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 Leishman's 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.

The free amino acids occurring in alcoholic extracts of fowl seminal plasma have been examined by filter-paper chromatography. Twenty-three have been detected consistently, and these include several that have not been hitherto reported in the seminal plasma of the domestic fowl. In addition, several unknown ninhydrin-reacting substances have been found. Glutathione and ergothioneine were not detected in the volumes of plasma chromatograhed. There was evidence of the presence of glycocyamine and an unknown imidazole compound. lb Riboflavin 4-48 g/tonUnextracted dried yeast 2-5 lb

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