K. G. Mitchell

Further studies on the water requirements of the growing pig

1. Results of an experiment involving 48 individually-fed pigs, covering the growing period between about 40 and 208 lb. live-weight, indicated that reduction in the amount of water allowed per lb. of meal from 3 lb. to 2 lb. or 1½ lb. had no significant effects on either the performance or the carcass quality of the pigs. 2. Provision of an unrestricted supply of water, in addition to the allowance of 1½ lb. added to each lb. of meal, resulted in a significant improvement in the rate of weight gain which was caused almost entirely by an increase in daily meal consumption by these pigs. 3. Under the conditions of the experiment, the provision of water ad lib . was not accompanied by any adverse effects on carcass quality, although conditions under which it might do so are discussed. 4. The data on water consumption of the pigs indicated that the observed effects on performance of providing water ad lib . did not arise as a result of a deficiency in the total water intake of the pigs given a restricted supply. The possibility is discussed that the length of time that water was available to the animals might be of importance.

Studies on liquid skim milk for growing pigs. The effect of its abrupt removal from the diet and of supplementation with copper sulphate or amino acids.

Results of four experiments involving a total of 124 pigs covering the growth period between about 40 and 210 lb. live-weight indicated that: 1. The growth rate and efficiency of food utilisation of pigs receiving liquid skim milk up to a maximum of 5¼ pints per head per day, was better than that of pigs receiving a balanced all-meal diet. This was equally so whether the liquid skim milk was fed throughout the growing period or was abruptly removed from the diet at either about 75 lb. or 120 lb. live-weight, provided the all-meal diet fed subsequently contained adequate protein. 2. The addition of 0·1% copper sulphate to the meal fed with liquid skim milk significantly improved the growth rate and efficiency of food conversion. 3. The addition of 0·2% dl-lysine and 0·1% dl-methionine to the meal fed with liquid skim milk had no effect on the performance of the pigs. 4. Withdrawal of a protein supplement from the rations of pigs after they reached about 120 lb. live-weight adversely affected their performance.

The value of feather meal as a protein supplement for growing pigs.

The results of a nitrogen balance experiment with growing pigs have shown that 5 % feather meal was inferior to 7 % white-fish meal, when both supplements supplied the same amount of total crude protein in a barleyweatings- minerals-vitamins ration. A comparative feeding trial in which white-fish meal was partially replaced by feather meal in the diets given to growing pigs gave inconclusive results.

The effects of different amounts of liquid skim-milk on pork pigs with particular reference to carcass quality.

1. Seventy-two individually fed pigs on six treatments were used to determine the effects on performance and in particular on carcass quality of ( a ) giving quantities of liquid skim-milk (preserved with formalin) in excess of those normally recommended; ( b ) replacing meal by skim-milk in the ration on a calculated dry-matter basis (1 gal. skim-milk equivalent to 1 · 1 lb. meal) as compared with a calculated energy basis (1 gal. skim-milk equivalent to 1 · 3 lb. meal) and ( c ) giving skim-milk for only a part of the growing period instead of throughout. The experimental period continued from 9–10 weeks of age until slaughter at an average live-weight of 135 lb. 2. Extensive carcass measurements were taken and in addition assessment of the carcasses was made by a representative of the County Quality Pork Association and by an expert pork butcher. 3. Carcasses from pigs given an all-meal diet were comparable in all respects with those from pigs given skim-milk throughout up to a maximum of either 5¼ or 10½ pints per pig per day. 4. Carcasses from pigs given the highest level of skim-milk (maximum of 15¾ pints per pig per day) were superior in many respects to those on any of the other treatments, but the possibility that this was due to their slower rate of growth rather than to the high level of milk per se , is discussed. 5. Pigs given skim-milk as replacement of part of their meal allowance on a calculated dry matter basis grew significantly faster than those in which the replacement was made on a calculated energy basis or than those given an all-meal diet. The importance is stressed of ensuring that in assessing the value of skim-milk for pigs the caloric value of the rations being compared is similar. The need for experiments based on actual determinations of the caloric value of the rations used is also emphasised. 6. While the performance of pigs given skim-milk up to 75 lb. live-weight only was similar to that of pigs given skim-milk throughout, evidence was obtained that the quality of their carcasses was slightly inferior. 7. There was some suggestion that as the level of skim-milk in the diet increased an eye muscle of a rather paler colour was produced.

Copper supplementation of isonitrogenous diets for growing pigs containing white-fish meal or soya bean meal as the protein supplement

1. Two trials were carried out to investigate the effects of high-copper supplementation of isonitrogenous diets containing either white-fish meal or soya bean meal as the sole protein supplement. 2. There was no difference in performance between the two diets when they were fed unsupplemented with copper in trial 1. The addition of 250 mg copper per kg diet significantly and similarly improved performance on both diets. 3. Liver-copper stores, but not kidney-copper stores, were significantly increased when the copper-supplemented diets were fed. The level of the liver-copper stores on the soya bean meal supplemented diet was, however, some 400g/kg less than that on the white-fish meal supplemented diet. The significance of this clearly established finding is discussed.

Evaluation of American and British rations for growing pigs

1. A test was carried out simultaneously in Shinfield, Reading, England, and Columbus, Ohio, USA, using typical British and American rations for growing pigs. The rations were compounded in their country of origin; half of each consignment was used at the home station and the other half shipped to the overseas station. 2. Both restricted feeding and ad lib . feeding methods were used at each station. 3. A similar pattern of results was obtained at Shinfield and Columbus. Pigs receiving the American ration, which was higher in energy content, grew faster and required less feed per kg live-weight gain than pigs receiving the British ration. The higher energy content of the ration was probably responsible also for the poorer carcass quality of the pigs receiving the American ration, particularly the high fat content. The comparison between restricted feeding and ad lib . feeding was not affected by the type of ration. Restricted feeding resulted in slower growth rate, slightly better efficiency of feed conversion and considerably better carcass quality.