ALBERT

Description: 1. Piglets reared in a cold building but in pens provided with electrically warmed or wooden beds weighed considerably more at 8 weeks old than piglets reared in pens with solid concrete floors covered with thin permeable cork-tar bricks. At 3 days and 3 weeks old there were no differences in live weight between the three groups.2. Before weaning at 8 weeks old the piglets reared on concrete floors had very much poorer appetites for solid food than had those from the other two groups.3. Although the blood haemoglobin concentrations of piglets on warmed and wooden floors rose between 3 and 8 weeks of age, the haemoglobin concentrations in the group on concrete floors fell. The differences in concentrations between groups at weaning just failed to be statistically significant at P = 0·05.4. Under the conditions of this experiment the provision of electrically warmed or wooden floors diminished but did not eliminate the incidence of a pathological liver condition in pigs which has been attributed to poor housing conditions.5. The low weaning weights, poor appetites, low haemoglobin concentrations at weaning and the presence of the liver disease in piglets born on concrete floors were probably interdependent, but the mechanism and direction of this interdependence could not be explained from the data collected.

Description: The experiment reported here involved thirty-two pigs from birth to bacon weight. During the 9 weeks before weaning sixteen pigs were reared on damp cold floors in a cold building and sixteen were reared on dry cold floors in the same building. After weaning all the floors were kept dry.Before weaning four out of the sixteen pigs in each treatment died, but only one, which was in the wet cold floor group, was suspected of having a liver disease which has been described by Naftalin & Howie (1949). A greater incidence of this disease was expected to occur under the cold environmental conditions of the experiment.After weaning one deformed pig was killed and three other pigs were killed at 40 weeks old. The latter three all had the liver disease. There was evidence that the disease had developed after the pigs were weaned and this indicated that it cannot necessarily be prevented by the provision of dry conditions in a cold house. The growth curves of two of the three pigs fitted the hypothesis that the disease is associated with cold environmental conditions, but the growth curve of the third suggested that it might have contracted the disease during the summer when the minimum air temperature was 54° F.The possibility was discussed that the liver disease is caused by a virus or low nutritional status interacting with the effects of cold environmental conditions.The two pre-weaning treatments had no dissimilar effects upon the piglets' weaning weights, blood haemoglobin levels and appetites for solid food, nor did they have any differential effect upon the growth rates and efficiencies of conversion of food to flesh of the pigs which survived to bacon weight. The bacon carcasses from the pigs born and reared to weaning on wet cold floors were shorter and fatter than those from pigs born and reared on dry cold floors. No explanation could be offered for this difference in carcass conformation.The rates of heat loss from a constant temperature water-bath to an uninsulated concrete floor upon which pigs had not lain were halved by the provision of ½ in. depth of chopped straw bedding. They were also halved if the measurements were taken after pigs had recently been lying on the bare floor, and under these circumstances the provision of ½ in. depth of chopped straw bedding cut the heat losses even further.

Description: 1. Pigs housed in both a good and a bad piggery were kept to a medium plane of feeding on diets with and without a procaine penicillin supplement. Antibiotic improved neither efficiency nor rate of growth in either piggery during the period from weaning to 100 lb. live weight, nor from then to slaughter at 200 lb. live weight. The average temperatures during the first half of the experiment were 43 and 51° F. in the bad piggery and in the sleeping pens of the good piggery respectively. During the second half of the experiment these averages were 54 and 58° F. respectively.2. Between weaning and 100 lb. live weight, pigs housed in the bad piggery grew 6% more slowly and 5% less efficiently than in the good piggery, but although the growth rates fitted in well with previous observations, neither difference was statistically significant in this experiment.3. Between 100 and 200 lb. live weight pigs housed in the good piggery grew 3% less efficiently than in the bad piggery, but there was no difference in rate of growth. The difference in efficiency was statistically significant.4. Carcasses from pigs housed in the good piggery were fatter than from pigs housed in the bad piggery. These fatter pigs also had higher killing-out percentages.5. Although dietary antibiotic supplement had no effect upon growth rates or carcass measurements, it resulted in higher killing-out percentages.

Description: 1. The rates of growth and efficiencies of food conversion between 45 and 100 lb. live weight of pigs kept to a low plane of feeding were most adversely affected during the winter months by bad housing conditions, wherein the average air temperature was 43° F. On the other hand, this bad housing had no adverse effect upon pigs of a similar size kept to a high plane of feeding.2. The summer season, with consequently higher environmental temperatures in both good and bad piggeries, only had a significantly beneficial effect upon the rates and efficiencies of growth of pigs of 45–100 lb. live weight kept to a low plane of feeding in a bad piggery. Any effects upon the growth of pigs of similar size kept to a high plane of feeding in either a good or bad piggery or to a low plane of feeding in a good piggery did not approach statistical significance.3. There was probably some environmental factor other than air temperature or relative humidity which had a beneficial effect on the growth of the pigs kept to a low plane of feeding in the good piggery.4. It was observed, but not proved, that pigs of 100–200 lb. live weight kept to a high plane of feeding grew rather more efficiently in the bad house than in the good house, despite the higher environmental temperatures in the good house.5. During the growth period between 45 and 100 lb. live weight the efficiency of food conversion, expressed in pounds t.d.n. required per pound liveweight increase, was better in the well-housed pigs kept to the low plane of feeding than in the highplane pigs housed in either piggery.6. During the growth period between 100 and 200 lb. live weight the efficiency of food conversion of the well-housed low-plane pigs was significantly better than that for the well-housed high-plane pigs, but was not significantly better than the efficiency of food conversion of the high-plane pigs from the bad piggery.

Description: 1. The pigs in the three experiments reported were weaned at 10 days old and fed water and drymeal diets ad libitum until they reached 25 lb. live weight. They were housed individually in cages and records were kept of each pig's food consumption and of its live weight every third day.2. Most of the diets fed were based on roller-dried skim milk, rolled oat groats, white fishmeal, sucrose, dried yeast, cod-liver oil, minerals and antibiotic.3. Forty-eight pigs were used in Exp. 1, which was designed as a 4 × 2 factorial. Food-conversion efficiency was significantly improved by 10% when the crude protein in the diet was raised from 24 to 29%. Increasing the protein to 34 or 39% brought no further significant improvement. There were no significant differences between growth rates which were attributable to the four levels of protein.The inclusion of 10% sucrose in the diet did not result in increased food consumption, but there were significant improvements of 8% in growth rate and 10% in food conversion efficiency. There were no treatment interactions.4. Twenty-four pigs were used in Exp. 2, which was designed as a 2 × 2 factorial. Figs fed a diet containing 7% fat grew 4% faster and 6% more efficiently than others fed a diet containing 3·7% fat, but neither difference approached statistical significance. There was no advantage in feeding the meal as a slop, indeed, there was a tendency for the pigs to scour more than on dry feeding. As in Exp. 1 there was no treatment interaction.5. Forty-eight pigs were used in Exp. 3, which was designed as a 2 × 2 × 2 factorial. The basal diet contained about 30% crude protein and 10% sucrose.An increase in the antibiotic level from 18 to 112 mg./lb. diet significantly increased growth rate by 7%, but the 9% increase in efficiency of food conversion was not statistically significant.The addition of a trace mineral supplement significantly improved rate of gain by 7%, but the 6% increase in efficiency of food conversion was not statistically significant.The addition of a complex vitamin mixture had no significant effect upon either rate or efficiency of growth.6. In all three experiments the shape of the growth curve of pigs weaned at 10 days old wag divided into two periods. During the initial ‘check period’, lasting about 10 days, the pigs ate only small amounts of food, grew very slowly, and sometimes scoured. After the ‘check period’ there was a sudden change to the ‘growing period’, during which the pigs ate increasing amounts of meal and grew rapidly.The only treatment which significantly affected the length of the check period was in Exp. 3, when the addition of the vitamin supplement to a diet containing a high antibiotic level shortened the check period by 3 days but then counteracted this advantage by reducing rate of gain during the growing period.7. Between 25 lb. weight and 8 weeks of age twenty-four pigs from the experiments reported were fed ad libitum on a dry-meal diet containing 22% crude protein. The average live weight of these pigs at 8 weeks was 49 lb.

Description: 1. Growth and feed conversion efficiency of pigs between weaning and 100 lb. live weight were improved by adding a vitamin B12 a supplement to simplified all-plant rations containing, principally, barley and groundnut meal. This response was obtained with less than one-third of the U.S. recommended allowance of vitamin B12 in the rations of growing pigs.2. No such response was obtained when a vitamin B12 supplement was added to rations containing milling by-products and grass meal.3. When pigs were fed to a scale based on live weight, those that received an all-plant ration (containing milling by-products and grass meal, and relying on groundnut meal as the main source of supplementary protein to give a total content of 18·4 to 18·8% crude protein) gave 90–93% as good growth as pigs that were fed rations of similar total digestible nutrient content containing 14·5–15·5% crude protein and 3·6 or 7·0% white fish meal. Calculations suggest that such groundnut meal rations may be slightly deficient in lysine, but probably not deficient in tryptophan or ‘cystine + methionine’.4. When pigs were fed to appetite, those that received rations containing 3·6% white fish meal and no milling by-products or grass meal, ate significantly more than those that had either ‘milling by-products + grass meal’ or no fish meal in their rations; they grew proportionately faster, with no improvement in the efficiency of feed conversion.5. The carcasses of pigs that had received all-plant rations from weaning to bacon weight were of good quality, and their measurements did not differ from those of pigs that had received fish meal to 100 lb. live weight.

Description: 1. A review of the literature indicated: (a) A lack of agreement upon whether or not restriction of the plane of feeding from weaning or 100 lb. live weight to bacon weight improves efficiency of food conversion. (b) That a severe restriction of the plane of feeding improves carcass-quality measurements, (c) That a less severe restriction of food intake brings the total growth period within a range more acceptable to the farmer, but only has a small effect in improving carcass quality, (d) That the small benefits to quality from this less severe restriction may be equalled or surpassed by quite small changes in the genetic ‘type’ of pig fed. (e) That there are probably interactions in the response of different ‘types’ of pig to different planes of feeding.2. Two experiments were undertaken. In Exp. 1 both Large White × Swedish Landrace pigs and Large White × Wessex Saddleback pigs were fed from weaning to bacon weight to one of three planes of feeding. Exp. 2 was very similar in design except for some modifications to planes of feeding and the substitution of Essex Saddleback × Large White pigs in place of the Wessex crosses.3. In Exp. 1 the planes of feeding, according to our stated definitions in terms of total digestible nutrients consumed daily at different live weights, were: very high during both growing and finishing periods (VH-VH); very high during the growing period but restricted during the finishing period (VH-R); and very low during both growing and finishing periods (VL-VL). In Exp. 2 the planes of feeding were: VH-VH; VH-R, the restriction being slightly more severe than in Exp. 1; and low during both growing and finishing periods (L-L).4. In Exp. 1 there was no difference in growth rate between breed crosses. Pigs on the VH-R and VL-VL planes were 12 and 88 days older respectively at bacon weight than those fed to the VH-VH plane. In Exp. 2, Landrace crosses grew faster than the Essex crosses on the VH-VH and VH-R planes, but Essex crosses grew faster on the L-L plane. Landrace crosses fed to the VH-R and L-L planes were 11 and 63 days older respectively at bacon weight than others fed to the VH-VH plane. Essex crosses fed to the VH-R and L-L planes were 16 and 53 days older respectively at bacon weight than others fed to the VH-VH plane.5. In Exp. 1 there was no difference in food-conversion efficiency (f.c.e.) between breed crosses. There was no significant difference in f.c.e. between the VH-VH and VH-R planes, but there was a loss of 14% in F.C.E. on the VL-VL plane. In Exp. 2 the Landrace crosses had better F.C.E.'s than the Essex crosses on the VH-VH and VH-R planes, but Essex crosses were the more efficient on the L-L plane. There was no significant difference in F.C.E. between the VH-VH and VH-R planes for either breed cross, but there were losses in efficiency of 4 and 14% on the L-L plane for the Essex and Landrace crosses respectively.6. In Exp. 1 the Landrace crosses had less back fat over the shoulder than had the Wessex crosses. Pigs of both crosses fed to the VH-R plane had smaller fat measurements than those fed to the VH-VH plane, but this improvement was only significant for minimum back fat. Landrace crosses also had less fat over the ‘eye’ muscle when fed to the VH-R plane, but this did not apply with the Wessex crosses. The difference in carcass quality attributable to the restricted plane of feeding after 100 lb. live weight was considered to be equalled by the difference between breed crosses. The improvement in carcass-quality measurements between pigs fed to the VH-VH and VL-VL planes surpassed the difference between breed crosses, but the carcasses tended to be soft. However, no data were available on the iodine numbers of the fats.7. In Exp. 2 the Landrace crosses had less fat over the shoulder and over the eye muscle and smaller minimum back-fat measurements than had the Essex crosses. Pigs of both crosses fed to the VH-R plane had smaller fat measurements than those fed to the VH-VH plane, the difference being significant for shoulder fat and minimum back fat. Again the differences between the effects of these two planes of feeding and between the two breed crosses were considered about equal, and again the difference between breed crosses was surpassed by the difference between the carcass measurements of pigs fed to the VH-VH and L-L planes. In Exp. 2 the effects of planes of feeding upon length of carcass, thickness of streak, percentage fore and percentage middle differed significantly between the two breed crosses.8. When carcass data from both experiments were compared it was apparent that differences between breeds or strains of bacon-type pigs are likely to be of more importance in the production of high-grade bacon than attempts to alter the conformation by varying the plane of feeding—and thus the growth curve—within the limits acceptable in practice.9. Although previous evidence indicates that males grow faster than females, there was in Exp. 1 no significant difference in growth rate between the sexes. In Exp. 2 there was again no overall significant sex effect, but during the finishing period females grew faster than males on the VH-VH and VH-R planes, but males grew the faster on the L-L plane. In Exp. 1 there was no significant difference between sexes in F.C.E., but in Exp. 2 males were less efficient than females on the VH-VH and VH-R planes, but were the more efficient on the L-L plane, this interaction again developing principally during the finishing period.10. In both experiments females had carcasses which were longer, had less fat, larger areas of ‘eye’ muscle and larger hams than males. In both experiments the restricted plane of feeding after 100 lb. live weight reduced the shoulder-fat measurements of females but had no effect on those of males which, being the fatter, had the greatest need of improvement to achieve the highest grade. However, the statistical significance of this interaction was low and it requires confirmation.11. It is not the intention of the authors that these results should be taken to apply in general to the breed crosses used. The breed crosses were chosen solely as pigs which would differ somewhat in genetic type from each other.12. The results from these experiments confirmed the indications from the literature which have been noted in paragraph 1 of this summary. The results and some of their implications have been discussed in the text.

Description: Groups of pigs were weaned at 8, 14 and 20 lb. live weight from each of seven litters. Each of the twenty-one groups was housed separately and selffed a 30% protein diet ‘A’ up to 25 lb. live weight.From then until 56 days of age each group was selffed a 22% protein diet ‘B’.Weight at weaning had no significant effect on age at 40 lb. live weight, but weights at 56 day old of 46·5, 50·2 and 47·7 lb. for pigs weaned at 8, 14 and 20 lb. respectively tended to favour weaning at 14 lb. (P 〈 0·10).Pigs weaned at 8, 14 and 20 lb. each required 25, 16 and 6 lb. respectively of expensive diet ‘A’ to reach 25 lb. live weight. To grow from 25 to 40 lb. live weight they each required 30, 28 and 27 lb. of diet B, and this trend in favour of the pigs weaned at heavier weights was significant at P 〈 0·05.These results are discussed in relation to the system of early weaning.

Description: 1. The main experiment described was a 4 × 2 factorial designed to test levels of 18, 21, 25 and 28% crude protein in diets fed from 25–50 lb. live weight and to compare an all-vegetable diet with one containing white fish meal for pigs of 50–100 lb. live weight.Forty-eight pigs were used in the experiment. They were weaned at an average weight of 9 lb. and were fed a standard 29% protein diet until they each weighed 25 lb. Between 100 lb. and slaughter at 200 lb. they were fed a standard all-vegetable diet containing 14% protein.Live weights and food-consumption figures for each pig were recorded throughout the experiment and carcass-quality measurements were taken.2. Forpigs of 25–50 lb. there was no advantage in raising the level of crude protein above 18% in a diet based on white fish meal, dried skim milk, rolled oat groats, ground barley and fine millers' offals. Level of protein fed during this stage of the experiment did not affect performance at any subsequent stage, nor did it affect carcass quality.3. For pigs of 50–100 lb. rates of live-weight increase and food-conversion efficiency were poorer by 13 and 14%, respectively, on an all-vegetable diet containing 17% crude protein than on a diet including 7·5% white fish meal and containing 15% crude protein. This difference was not affected by level of protein fed before 50 lb., and in its turn it did not affect either growth performance from 100–200 lb. or carcass quality measurements.4. The following notes relate to the overall performance of early weaned pigs during this experiment: After being weaned at an average of 9 lb. when 10 days old, the pigs reached 25 lb. at 36 days old and 50 lb. at 58 days old. They each ate an average of 29 lb. of the 29% protein diet 1A and 59 lb. of the diets 2 A–D fed from 25–50 lb. Between 50 and 200 lb. food-conversion efficiencies were lower than is usual for individually fed pigs at the Rowett Institute, but rates of live-weight increase were satisfactory when considered in relation to the plane of feeding followed, and the average age at 200 lb. was 185 days. Of the carcasses 85% graded A.5. In a pilot trial pigs were changed over from the 29% protein diet 1A to the 18% protein diet 2D at 13, 17, 21 or 25 lb. live weight.There was a linear trend towards slower rates of live-weight increase as the weight at change-over was reduced, and pigs changed at 13 lb. took 7 days longer than those changed at 25 lb. to reach 40 lb. live weight. Overall food-conversion efficiency was best when the change was made at 25 lb., but because of the high cost of diet 1 A in relation to diet 2 D there was a linear trend for the total cost of food per pig to be lower as the weight at change-over was reduced.6. The results of the pilot trial were discussed in relation to the effects on the lightest pigs in a group of changing to diet 2 D as the average weight per pig reached 25 lb.

Description: 1. One hundred and sixty-eight pigs were used in four experiments to test the value of including antibiotics and copper sulphate, either as separate supplements or together in rations for growing pigs. Procaine penicillin was added at the rate of 5·36 mg./lb. diet and Aureomycin (in Aurofac 2 A) at 8·03mg/lb. and CuSO4. 5H2O as 0·1% of the diet.2. During the growing period in Exp. 1, pigs fed diets supplemented with copper sulphate or procaine penicillin grew 9 and 3% faster respectively than the controls. Pigs fed a diet containing both supplements grew 22% faster than the controls. During the finishing period there was an outbreak of virus pneumonia and the within-treatment variability was large. There were no significant differences between treatments during this period, although pigs fed the supplemented diets tended to grow more slowly than the controls. Over the total experimental period pigs fed the diet supplemented only with copper sulphate grow 2% faster than the controls, and those fed the diet supplemented with both procaine penicillin and copper sulphate grew 4% faster than the controls, but these small average improvements were not statistically significant. In Exp. 1 treatment differences in food conversion efficiencies paralleled those for growth rates. Killing-out percentages were higher when pigs were fed the copper-supplemented diets, and lower when procaine penicillin was fed. The area of ‘eye’ muscle was increased by adding procaine penicillin to the diet.3. During the growing period in Exp. 2, pigs fed diets supplemented with copper sulphate or with both procaine penicillin and copper sulphate grew 8 and 9% faster, respectively, than the controls. The addition of procaine penicillin had no significant effect when added as a single supplement or in conjunction with copper sulphate. During the finishing period pigs fed diets supplemented with copper sulphate, procaine penicillin, or both copper sulphate and procaine penicillin grew 5, 3 and 10% faster, respectively, than the controls, while over the total experimental period they grew 4, 0 and 9% faster, respectively.4. Some pigs fed the copper-supplemented diets during the growing period in Exp. 2 were fed diets with no copper added over the finishing period. During this latter period the pigs grew at about the same speed as the controls, and significantly more slowly than those pigs which continued to receive copper sulphate. Thus, the average growth rates over the total experimental period were significantly slower by 3–7% when copper was omitted after 100 lb. than when it was fed to the pigs throughout the entire experiment.5. In Exp. 2, as in Exp. 1, treatment differences in efficiency of food conversion paralleled those for growth rates. A higher rate of growth was always accompanied by an improvement in efficiency of food conversion, with about the same percentage difference between treatments. Indeed, changes in rate of growth were probably dependent upon changes in efficiency of food conversion, since all pigs were fed to the same scale based on live weight.6. The treatment differences in killing-out percentage and area of eye muscle observed in Exp. 1 were not confirmed in Exp. 2. There were no differences in carcass quality measurements attributable to the treatments imposed in Exp. 2.7. The livers of pigs fed diets containing copper sulphate during both the growing and finishing periods had, on average, about eighteen times the concentration of copper found in the controls. When the copper sulphate supplement was fed only during the growing period the liver copper concentrations were, on average, about four times those of the controls. However, the variation between the individual values was very large in all groups fed copper sulphate. This variation may have been caused partly by sampling errors if copper is not distributed evenly throughout the liver.