701. A comparison of dried skim-milk and white fish-meal as protein supplements for fattening pigs

Abstract

1. Thirty-six 9–11-week-old Large White pigs in nine blocks of four litter-mates were individually fed on diets containing either white fish-meal or various amounts of dried skim-milk as the protein supplement. The pigs were fed according to live weight and a scale up to a maximum of 6½ 1b. of meal/pig/day.2. There were no significant differences in rate of growth or efficiency of food utilization between pigs given the diets containing as protein supplements either 10% white fish-meal reduced to 7% at 130 1b. live weight, 10% dried skim-milk reduced to 7%, or 15% dried skim-milk reduced to 10½%.There was, however, a trend towards an improvement in both rate of growth and efficiency of food utilization with increasing levels of skim-milk in the ration, and the differences between the high skim-milk diet (20 reduced to 14%) and the low (10 reduced to 7%), and also between the former and the fish-meal diet, reached statistical significance.3. The difficulties of drawing any definite conclusions from the results about the relative value of the protein in white fish-meal and dried skim-milk were discussed in relation to (a) the probability that the white fish-meal diet used contained over-generous supplies of protein, and (b) the higher energy value of dried skim-milk as compared with white fish-meal.4. The commercial grading of pigs on all four treatments was very good. The carcass measurement data indicated a tendency for the skim-milk diets, particularly those containing either 10 or 15%, to result in some increase in both back fat and belly thickness. The possibility that this was associated with the higher energy/protein ratios in the skim-milk as compared with the white fish-meal diets was discussed.