G. Harrington

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.

A comparison of litter-mate pigs slaughtered at 200 and 260 lb. live weight.

1. A co-ordinated trial has been carried out at eight centres to compare the performance of group-fed pigs slaughtered at about 200 lb. live weight (bacon weight) with that of litter-mates slaughtered at 260 lb. (heavy pigs). 2. The bacon pigs were fed either ad lib. or restricted according to live weight, while the heavy pigs were all fed ad lib . with one group having the protein supplement withdrawn from the ration after the pigs had reached 140 lb. live weight. 3. Growth rate, efficiency of food conversion and carcass quality (based on dissection) data are summarized in Table 5. 4. In general, the results indicated that under the conditions that prevailed, and when the leanness of the carcass is the major consideration, the slaughter weight around 200 lb. was preferable to the heavier weight (about 260 lb.) both from the production and economic aspect.

Visual judgements of quality in meat III. Assessments of bacon qualities by naïve and experienced judges using photographic reference standards

1. Two panels of eight students, with no previous experience in scoring bacon sides for eye-muscle qualities or for fatness, co-operated in an experiment involving thirty-five photographs of back rashers of bacon presented to them in batches of twenty at a time. The members of the first panel made their assessments without any guide, whereas those of the second were provided with sets of photographic reference standards showing a graded sequence of rashers scoring from 0 to 10 for each of the two characteristics involved. 2. Those provided with the reference standards spread out their scores over the available range more than those who judged without them. 3. Judging discrimination between markedly different groups of rashers was improved when the reference standards were available. This was not true of discrimination between similar rashers since repeatability of scoring was to some extent decreased when the standards were used. 4. When the reference standards were not available, these inexperienced judges tended to adjust their level of scoring according to the quality of the batch of rashers being assessed. This adaptive effect was eliminated when reference standards were available although apparently random fluctuations of level of scoring from batch to batch still occurred. 5. Differences between judges due to their different uses of the available range of scores were less marked, although not entirely eliminated, when reference standards were used by the naive judges. Systematic differences between the scores awarded by various judges remained, as did a few differences of opinion on the relative quality of certain examples.

Carcass length measurement in bacon pigs

1. Two experiments involving length measurements of ninety-six bacon-pig carcasses showed that chopping out the backbones, chilling and laying the carcasses down on a table, each resulted in a decrease in average length. There was variation from carcass to carcass in the magnitude of these decreases which, in the case of the chopping out the backbone and laying down stages, was related to the fatness of the carcass, greater decreases being found in the longer, leaner carcasses than in the shorter, fatter sides. 2. Estimates of the precision of measuring showed that length from the junction of the first rib and the sternum to the symphysis pubis taken on hanging carcasses was less susceptible to errors than the same measurement taken on the lying carcass, and that both these measurements were more accurate than that from the atlas bone to the symphysis pubis taken on carcasses either hanging or lying.

The effect of antibiotic dietary supplements on the carcass measurements and dressing percentage of bacon pigs

1. Certain carcass measurements (length, shoulder and mid-back fats, belly thickness and dressing percentage) made on a total of 402 bacon pigs from four antibiotic feeding trials have been analysed. 2. The length of the carcasses showed more variation between pens treated with various doses of penicillin than between control pens or pens treated with aureomycin. This greater variation in length was related to the greater variation in growth rate between the penicillin treatments. No differences in the mean lengths of control, penicillin and aureomycin treatments were found. 3. Back fat measurements and belly thickness showed no differences between aureomycin, penicillin and control treatments in overall tests. 4. Aureomycin consistently gave higher dressing percentages than penicillin. Animal protein also gave higher dressing percentages than vegetable protein, but no effect of vitamin B12 on this quantity was found.