Search

Results of experiments to investigate the effect of dietary chlortetracycline on pancreas dry weight and on the crude fat content and hydrolase activity of the gland are presented. Chlortetracycline fed at a level of 20 g. per ton of feed caused an increase in rate of gain and efficiency of feed utilization by pigs between the ages of 9 and 17 weeks. An effect on the pancreas was indicated by significant increases in: (a) dry weight, (b) total protease and amylase activity, and (c) amylase activity per gram dry matter of the glands from animals receiving the supplemented ration. The difference remained significant after adjustment for body weight by covariance in the case of amylase activity but not for dry weight or protease activity, indicating that the effect of chlortetracycline on amylase activity was more pronounced than that on rate of gain of pigs, pancreas dry weight, or pancreatic protease activity. No significant difference in the crude fat content of the pancreas attributable to the inclusion of chlortetracycline in the ration was observed.

Sixty-four Hampshire × Yorkshire barrows and gilts were fed barley-fishmeal, barley-meat meal, barley-soybean meal or barley-rapeseed meal diets with or without 250 mg supplemental copper per kg diet. Daily feed intake averaged 2.5 kg and was not influenced by dietary protein source or supplemental copper. Pigs receiving the barley-fishmeal and barley-soybean meal diets gained more rapidly and required less feed per kilogram gain than those fed the barley-meat meal or barley-rapeseed meal diets. Rate of gain and feed conversion efficiency were not significantly influenced by supplemental copper.In comparison with animals receiving the basal diets, copper supplementation of the fishmeal, meat meal and soybean meal-supplemented diets resulted in a significant increase in the proportion of UFA and a concomitant decrease in the proportions of SFA present in the backfat of pigs at 34, 45, 57, 68, 79 and 88 kg live weight. Copper supplementation of the barley-rapeseed meal diet did not result in similar changes.

Some factor or factors, either one or more of the other known B-complex vitamins not included in the purified ration used, or some unknown factor(s) is essential for reproduction and lactation in swine. The storage of this factor or factors in the sow must be sufficient to carry her for a long period of time as evidenced by the good record made by the two control gilts which were fed the purified basal ration (supplemented with the fat soluble vitamins (A, D, E, K) and the six B-complex vitamins: thiamine, riboflavin, niacin, pyridoxine, pantothenic acid, and choline) only during the last 52 days of gestation and through a lactation period of 42 days, whereas complete failure in lactation was obtained when the same ration was fed for 140 days prior to farrowing.The deletion from the ration of any one of the three B-complex vitamins, thiamine, riboflavin, or choline, resulted in unsatisfactory reproduction and lactation. These results most likely are all complicated by an incomplete control ration so the following data obtained cannot be stated to be due to an uncomplicated single vitamin deficiency:(A) Results with gilts fed ration with no thiamine added: (1) Some loss of appetite, but not consistent; (2) Efficient feed utilization obtained during pregnancy; (3) Parturition 9 and 11 days prematurely in two cases; (4) High birth mortality in litters; (5) Weak-leg condition in pigs at birth; (6) Unthrifty pigs and subnormal weaning weights. Postmortem and microscopic data are given. (B) Results with gilts fed ration with no riboflavin added: (1) Erratic or, at times, a complete loss of appetite in pregnant gilts which was restored by injections of thiamine; (2) Poor gains; (3) Parturition 4 to 16 days prematurely; (4) One case of death of fetus in advanced stage with resorption in evidence; (5) All pigs were either dead at birth or died within 48 hours thereafter; (6) Enlarged front legs, due to gelatinous edema in the connective tissue in 9 pigs, and generalized edema in many pigs; (7) Two hairless litters born. Postmortem and microscopic data are given and discussed. (C) Results with gilts fed ration with no choline added: (1) Appetite of sows good; (2) Gilts farrowed on schedule; (3) At birth, many of pigs showed weak leg conditions such as those observed on thiamine deficient ration. (4) Muscular incoordination was observed in some pigs; (5) Heavy mortality in pigs and subnormal weaning weights; and (6) Fatty livers in pigs. Additional postmortem and microscopic data are given.Cases of hernia, kinked tail, enlarged forelegs, liver and kidney abnormalities occurred in pigs farrowed by various of the sows receiving the purified rations. The use of litter mate gilts in the 1946 trials and the normal appearance of the pigs from the control gilts seem to limit the abnormalities being due to genetic variation. The weak legged condition and general weakness at birth of pigs was so prevalent that it appeared to be nutritional. It would seem that much of the variation in severity of abnormalities could be attributed to differences in the length of time the sows were fed the purified ration and therefore variation in the amount of depletion of the factor(s) involved.Results of analyses of certain tissues for riboflavin and thiamine, of the gilts and pigs used in the 1946 trials, are given and discussed.

Twenty-four Hampshire × Yorkshire barrows were fed a barley-fishmeal diet. A comparison was made between the diet without added copper (containing 6 mg. Cu/kg. diet) and one with 280 mg. supplemental copper/ kg. diet. The pigs were restricted to a scale of feeding based on liveweight. Copper supplementation of the diet resulted in a significant increase in the proportion of unsaturated fatty acids in the outer backfat, inner backfat and perinephric fat at 26, 47 and 70 kg. liveweight. There was a corresponding decrease in the proportion of saturated fatty acids. No significant differences were found in fatty acid composition of these fats at 90 kg. liveweight, although the former pattern of distribution still existed. The increase in the proportion of unsaturated acids could be accounted for largely by increases in 16:1 and 18:1 fatty acids with corresponding decreases in 16:0 and 18:0 acids.

When pigs were not fasted prior to bleeding, there was a significant correlation between plasma lipid levels taken at 100 lb. in weight and average backfat thickness, but no appreciable correlation of plasma lipid levels with loin area or rate of gain. Following a 16- to 18-hour fasting period prior to bleeding so that the pigs were allowed to approach a post-absorptive state, there were significant or highly significant correlations of plasma lipids with shoulder fat, back and loin fat, combined shoulder, back and loin fat, and area of loin muscle, while plasma lipid correlations with average daily gain approached significance at the 5% level. A correlation of .70 was found between plasma lipids taken from individuals at 100 lb. and at 200 lb. liveweight.The results indicate that plasma lipid levels taken from pigs weighing approximately 100 lb. would be of some use to supplement other measures in estimating fat and lean content of pig carcasses at market weight. In individual fasted pigs, the relationship of plasma lipids to rate of gain is sufficiently high to indicate some physiological relationship.

Data are presented to show that the vitamin A content of the blood plasma of suckling pigs is positively correlated (highly significant) with the level in the blood plasma of their dams. From these data regression equations were formulated which predict the vitamin A level in the blood plasma of suckling pigs from the vitamin A level in the blood plasma of their dams.The most accurate prediction was made when the suckling pigs were 4 weeks of age, when a regression equation of Ÿ=0.473X+10.8 was obtained. About 45% of the original variation could be controlled by the use of this equation.Blood plasma level of vitamin A in the suckling pigs was unrelated to sex.

The total solids, solids-not-fat, protein, lactose, and ash content of sow's milk are reported for two groups of sows, one group on pasture, and one group in dry lot. The sows were milked manually after the injection of 1 ml. of Pitocin, on the first day of lactation, the third day, at the end of the first week, and each subsequent week throughout lactation.The mean values of milk constituents for pasture sows were, for first day colostrum: total solids 22.81 percent, solids-not-fat 15.92 percent, protein 11.25 percent, lactose 2.89 percent, and ash 0.72 percent; for later milk: total solids 19.47 percent, solids-not-fat 13.16 percent, protein 7.09 percent, lactose 5.18 percent, and ash 0.99 percent. The mean values of milk constituents for dry-lot sows were, for first-day colostrum: total solids 22.81 percent, solids-not-fat 17.21 percent, protein 14.29 percent, lactose 3.42 percent, and ash 0.73 percent; for later milk: total solids 20.69 percent, solids-not-fat 13.38 percent, protein 7.42 percent, lactose 5.08 percent, and ash 0.98 percent.

The vitamin A and vitamin C levels of colostrum and normal milk are reported for ten sows carried through growth and gestation on pasture and for ten sows carried through growth and gestation in dry-lot.The sows were milked manually after the injection of 1 ml. of Pitocin, on the first day of lactation, the third day, the first, week, and each subsequent week until weaning at eight weeks of age.The mean values for vitamin A are: first and third day colostrum from pasture sows 143.6 γ/100 ml., from dry-lot sows 132.9 γ/100 ml.; normal milk from pasture sows 52.7 γ/100 ml., from dry-lot sows 34.8 γ/100 ml. of milk.The mean values for vitamin C are: first day colostrum from pasture sows 18.8 mg./100 ml., from dry-lot sows 24.6 mg./100 ml.; normal milk from pasture sows 10.4 mg./100 ml., from dry-lot sows 12.2 mg./100 ml. of milk.

POTENTIAL utilization of urea as a nitrogen source in pig diets offers an inexpensive alternative to existing protein sources. Utilization of non-protein nitrogen (NPN) compounds by ruminants is well documented (Briggs, 1967). Monogastric species are less adequately equipped to utilize dietary NPN compounds because microbial fermentation is poorly adapted in this type of digestive tract. It has been suggested by Kornegay et al.(1965) that 1% urea can be utilized by pigs as long as provision is made for replacement of essential amino acids lost by removal of protein from the diet. Experiments reported here are a continuation of earlier studies reported by Bowland and Grimson (1970).General objectives of the experiments were to evaluate the use of 2% urea and of the essential amino acids, L-lysine and DL-methionine, as supplements to practical-type diets of pigs from 4 weeks of age to market weight.Design and Allotment. In Experiments 1 and 2, an evaluation was made of the effects of 2% dietary urea isonitrogenously replacing herring meal protein, and of 0.38% L-lysine-monohydrochloride and 0.12% DL-methionine supplements on feed intake, gain and feed conversion of 4 to 11 week old pigs started on experiment at an average of 6 kg live weight (table 1).

RESPIRATION calorimetry is necessary to delineate completely energy utilization by animals. Laboratories in Germany and Denmark have reported results of extensive research on heat production and energy balance of growing pigs (Oslage and Fliegel, 1965; Thorbek, 1969) and of adult pigs (Nehring, Hoffmann and Schiemann, 1963). There have been, however, no studies specifically designed to evaluate the influence of crude fiber (CF) levels on overall energy utilization and heat production by market pigs. It is well established that CF depresses the digestibility of a diet. The source of CF may also be a factor in energy utilization as CF from different sources had different digestibilities (Troelsen and Bell, 1963). Lloyd and Crampton (1955) determined that one unit of CF was inversely equivalent to one unit crude protein (CP).The present study using respiration calorimetry was designed to obtain data on energy utilization and nitrogen balance of castrate male growing pigs from approximately 25 to 74 kg live weight when they were fed diets calculated to contain 3, 6, 9 or 12% CF.

The high cost of producing weaned pigs is associated with low annual output of number and weight of pigs per sow, which means that high overhead costs are spread over too few kg. of marketed pork. To improve over-all efficiency of energy utilization, feed costs should be spread over more young pigs. The sow has a relatively high energetic efficiency during lactation, but this still results in low efficiency of sow feed conversion to piglet gain. The sow cannot compete with the direct conversion of feed energy to lean meat and fat. The most efficient over-all utilization of feed is to be obtained by giving as little as possible within the limits of normal reproductive performance during pregnancy, and as much as the sow requires for milk production during lactation, along with as much as possible directly to young pigs.This review suggests that a system of feeding that attempts to maintain the true weight (total energy content of the body) of sows during lactation and to allow no gain in weight above that accounted for by the fetuses and fetal membranes during gestation would allow the maximum energetic efficiency. Changes in water balance during lactation and gestation and possible changes in fat-muscle ratios during these periods must not be confused with energy maintenance. For gilts, and possibly for second litter sows, an energy allowance for normal growth would also be required. To lower maintenance requirements, relatively low mature weights would be desirable. Direct energy conversion by the young pig by allowing it to eat as soon as possible should also be encouraged as an aid to total energetic efficiency.

An experiment was conducted during two seasons to study the value of 0.2 L-lysine and/or of 1 mg. of hydroxyzine hydrochloride per pound of ration as supplements to a low protein ration for growing pigs.The addition of lysine to a 13% protein (0.55% lysine) barley-wheat-SBM growing ration for individually-fed pigs from 36 to 110 lb. liveweight increased rate of gain and efficiency of feed utilization so that they were essentially equal to those obtained with a 16% protein (0.75% lysine) ration. The pigs receiving the lower protein, 7% SBM, ration without supplemental lysine gained 10% more slowly and required 13% more feed per pound gain than those fed the higher protein, 15% SBM, ration. The addition of hydroxyzine hydrochloride to the lower protein ration during the growing period did not influence rate of gain or efficiency of feed utilization.The results of an experiment with weanling rats were similar to those obtained with growing pigs, except that supplemental lysine failed to raise the performance of the rats to as high a level as that of rats receiving a higher protein diet.All pigs were finished from 110 lb. to market weight of over 190 lb. on the 13% protein ration with or without tranquilizer. Hydroxyzine hydrochloride had no influence during this period. For the entire growing and finishing period there were no significant differences between lots in rate and efficiency of gain. Carcass characteristics, with the exception of length, were not significantly influenced by the ration fed, but pigs receiving higher protein or supplemental lysine in their growing rations had loin areas that were 6% larger than those fed lower protein rations without lysine.The barrows gained more rapidly than the gilts but the gilts had longer carcasses with less average backfat. There were several replicate differences associated with rate of gain and carcass characteristics.

Data are presented on the results of experiments with Yorkshire swine fed basal barley-oat rations supplemented with either all vegetable or mixed animal-vegetable protein.Pigs receiving an APF supplement without antibiotic gained slightly more rapidly and efficiently than the controls but the difference was generally not significant. The amount of response was somewhat greater on an all vegetable protein ration than on an animal-vegetable protein ration.An APF supplement containing residual aureomycin caused marked increases in rate and efficiency of gain when added to basal rations containing protein of either vegetable or mixed animal-vegetable origin. Unthrifty weanling pigs gave a very great response in increased rate and efficiency of gains to this APF supplement.There appeared to be a reduction in carcass quality of bacon-type hogs receiving APF supplementation throughout the growing and fattening period. This was particularly noticeable in those receiving a ration supplemented with APF containing aureomycin.

Pregestation intake of vitamin A percursors influences the A content in sow's milk. The vitamin A and D values in the milk of sows farrowing in February as compared with sows farrowing in April suggest a gradual depletion in the body stores of these two vitamins. Condition of a sow at the time of parturition influences the concentration of fat in the sow's colostrum.

Pigs slaughtered after feed and water were removed for 20 hr. dressed (head on) 78.6% based on unshrunk liveweight. Withholding feed or water singly or in combination for an additional 24 hr. resulted in a 5.0 to 5.7% liveweight shrink and 1.0 to 2.1% carcass weight shrink. Mixing the pigs with strange pigs during this period had no additional effect on dressing percent. Withholding feed for an additional 48 hr. resulted in a 7.9% liveweight shrink and 3.1% carcass weight shrink.Rats had liveweight and carcass weight shrinkages similar to those for pigs. Rats exposed to a wind velocity of 60 m./min. did not shrink more than the corresponding group when food and water were withdrawn for 24 hr., but they shrank more than the corresponding group when food and water were not withdrawn. Rats killed at 8 p.m. had a lower dressing percent than those killed at 8 a.m., although weight of digestive tract and contents did not differ significantly between these groups.Average backfat thickness was reduced 0.32 cm. when feed and water were withheld from pigs for 48 hr., but other carcass measurements were not significantly affected. Liver weight of rats decreased when food or water were withheld, but heart weights did not change.