UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA PROTEIN SUPPLEMENTS IN THE FEEDING OF PIGS E. H. HUGHES and N. R. ITTNER BULLETIN 661 February, 1942 UNIVERSITY OF CALIFORNIA BERKELEY, CALIFORNIA CONTENTS PAGE Dairy by-products, tankage, and fish meal as supplements to barley 4 Equipment and pigs used 4 Feeds used 4 Experiment 1 4 Experiment 2 5 Experiment 3 6 Experiment 4 7 Experiment 5 8 Experiments where tankage and fish meal were used 9 Discussion and summary 11 PROTEIN SUPPLEMENTS IN THE FEEDING OF PIGS 3 E. H. HUGHES 3 and N. E. ITTNER* Dairy by-products have always been important supplements to other feeds in growing and fattening pigs. From time to time new methods have made available by-products other than skim milk and whey. The results of several experiments to test the comparative values of some of these products are reported herein. Pertinent abstracts of experimental work reported are given in the following paragraphs. As Fairbanks and Mitchell 5 have shown, the proteins of milk are sen- sitive to the heat treatments employed in commercial drying. In the prep- aration of commercial roller-process and of preheated spray-process skim-milk powders, the biological value is reduced from about 90 to 82 although the digestibility is not appreciably affected. If scorching oc- curs during the process, the biological value is lowered from about 82 to 70, and the digestibility is also impaired. Greaves, Morgan, and Loveen 6 note a lowering of the digestibility of casein heated in a vacuum at a temperature of 140° C for 30 minutes. They give the average digestibility of raw untreated casein as 97 per cent. Robinson 7 at the Ohio Agricultural Experiment Station reports as follows: With a ration of yellow corn, tankage, linseed meal, ground alfalfa, salt mixture, and cod-liver oil, the addition either of about 1 per cent or of 4.5 per cent of dried skim milk resulted in slightly more rapid gains and in the use of a little less feed for a unit of increase in pigs weighing 40 to 115 pounds. The addition of similar amounts of dried skim milk in the same diet of pigs weighing 115 to 200 pounds had little or no effect. 1 Eeceived for publication July 1, 1941. 2 Aid in conducting these experiments was furnished through a grant from Amer- ican Dry Milk Institute, Inc. 3 Professor of Animal Husbandry and Animal Husbandman in the Experiment Sta- tion. 4 Associate in Animal Husbandry and Associate in the Experiment Station. 5 Fairbanks, B. W., and H. H. Mitchell. The nutritive value of skim-milk powders, with special reference to the sensitivity of milk protein to heat. Jour. Agr. Res. 51 (12):1107-21. 1935. 8 Greaves, E. O., A. F. Morgan, and M. X. Loveen. The effect of aminoacid sup- plements and of variations in temperature and duration of heating upon the biological value of heated casein. Jour. Nutr. 16(2) : 115-28. 1938. 7 Robinson, W. L. Skimmed milk and dried skimmed milk for pigs. Ohio Agr. Exp. Sta. Bimo. Bui. 23(192) :89-97. 1938. [3] 4 University of California — Experiment Station According to Bohstedt, Fargo, and Ries, 8 dried skim milk and dried buttermilk, figured on a dry-matter basis, have the same feeding value as liquid skim milk or buttermilk. DAIRY BY-PRODUCTS, TANKAGE, AND FISH MEAL AS SUPPLEMENTS TO BARLEY Equipment and Pigs Used. — In these experiments the pigs were kept and fed on concrete floors. In every case the various lots had comparable- sized sleeping quarters, outside pens, and water troughs. The animals went in and out at will. Because they did not have access to dirt or pas- ture, iron and copper were provided as a protection against anemia. The pigs were Poland Chinas, Duroc Jerseys, Berkshires, or crossbreds of these breeds. At the beginning of the experiments they weighed 35 to 45 pounds except in one experiment, where two of the lots averaged about 60 pounds. Feeds Used. — The feeds included rolled barley, salt (NaCl), calcium carbonate (CaCo 3 ), cod-liver oil (source of vitamins A and D), commer- cial casein, purified commercial casein (washed to free it of riboflavin and other water-soluble factors) , whey adsorbate (fuller's earth to which riboflavin and some proteins are adsorbed), whey powder (often known as dried whey), skim milk (fluid), skim-milk powder (drum process, dried on a heated drum), skim-milk powder (spray process, dried by being forced through a fine nozzle and falling through heated dry air), tankage, fish meal, and "stick" (a dry, water-soluble residue from the manufacture of fish meal) . Experiment 1. — This experiment, carried out in the summer of 1937, was intended to test the value of adding small amounts of protein to a barley ration and, further, to ascertain whether the addition of ribo- flavin to barley would be beneficial. The supplements were casein, skim- milk powder, and whey powder. Riboflavin was added in lot 4, in the form of whey adsorbate ; some riboflavin is also contained in commercial casein (lot 3), and skim-milk powder (lot 5). The results are shown in table 1. Where a supplement was added to the basal ration (lot 1), the rate of gain improved in all lots. The addition of casein in lots 2 and 3 and of skim-milk powder in lot 5 produced more efficient gains than in the basal (lot 1) . Whey adsorbate fed in lot 4 improved the rate of gain and also the efficiency of gain over that of lot 1. Whey adsorbate is composed of an inert clay with riboflavin and some protein adsorbed on the par- 8 Bohstedt, G., J. M. Fargo, and R. W. Ries. Is dried skimmilk or dried buttermilk an economical protein feed for pigs? Wisconsin Agr. Exp. Sta. Bui. 428:12-14. 1934. Bul. 66£] Protein Supplements in the Feeding of Pigs 5 tides. The results obtained were probably due to either the additional riboflavin or the protein supplied ; the inert clay had no nutritive value. In this experiment the most striking observation was that a small amount of casein added to a barley ration increased the rate of growth of the pigs and the efficiency of the ration. The addition of skim-milk powder composed of casein and other nutrients likewise markedly influenced the pigs in lot 5, in which only 424 pounds of feed was required for 100 pounds of gain ; but 495 pounds was needed in lot 1, where the ration TABLE 1 Experiment 1: Effect of Adding Small Amounts of Protein and Eiboflavin to a Barley Ration Ration constituents, expressed as percentages* Lot no. Num- ber of pigs Days on feed Aver- . age initial weight, pounds Aver- age final weight, pounds Aver- age daily gain, pounds Pounds feed consumed per 100 pounds gain Pounds dry matter per 100 pounds gain Barley, 97.5; salt, 1; calcium carbonate, 1.5 1 10 112 42.2 111.4 0.62 495 447 Barley, 96; salt, 1; calcium carbon- ate, 1.5; casein (purified), 1.5 2 10 112 44 .6 149.4 94 427 385 Barley, 96; salt, 1; calcium carbon- ate, 1.5; casein (commercial), 1.5. 3 10 112 43 .2 145.4 91 438 395 Barley, 96.5; salt, 1; calcium car- bonate, 1.5; whey absorbate, 1 . . . 4 10 112 44 1 123.3 0.71 479 432 Barley. 94; salt, 1; calcium carbon- ate, 1.5; skim-milk powder (drum 5 10 112 41.0 149.6 0.97 424 383 * Cod-liver oil fed at the rate of 10 cc per pig per week. consisted of barley, salt, and lime. The ration fed lot 1, used as a check diet, is not, however, a complete diet for the growing pig because the protein content is not sufficient for best results. Experiment 2. — This test was conducted during the summer of 1938 to determine whether soaking feeds such as barley and dairy products for 24 hours would be beneficial. Some producers had raised the ques- tion whether such rations would be more efficient if allowed to soak. Lot 1, fed barley, salt, and lime, was used as a check on the other lots. The data are presented in table 2. The animals of the group fed barley without a nitrogenous supple- ment were affected much as were those fed the same diet the previous summer (see table 1). The rate of gain of the pigs in lots 2 and 3 was similar, though the pigs fed skim-milk powder (lot 3) gained more effi- 6 University of California — Experiment Station ciently than those in lot 2 fed whey powder. When water was added and the feed soaked for 24 hours, the gain was less rapid and the utilization less efficient (lots 4 and 5) than in similar lots (nos. 2 and 3) fed the same diet dry. Experiment 3.— This trial, conducted during the fall and winter of 1938-39, was intended to yield information on the comparative value of TABLE 2 Experiment 2 : Effect of Soaking Barley and Dairy By-Products before Feeding Ration constituents, expressed as percentages" Barley, 97.5; salt. 1; calcium carbonate, 1.5 Barley, 94; salt, 1; calcium carbon- ate, 1.5; whey powder, 3.5 Barley. 94; salt, 1; calcium carbon- ate, 1.5; skim-milk powder (drum process), 3.5 Barley, 94; salt, 1; calcium carbon- ate, 1.5; whey powder, 3.5; soakedj Barley, 94; salt, 1; calcium carbon- ate, 1.5; skim-milk powder (drum process), 3.5; soakedt Lot Num ber of pigs Days on feed Aver- age initial weight, pounds 107 107 107 107 107 40 8 40 3 38. 39. Aver age final weight, pounds pounds 110.0 126.8 126. 119.0 116.5 Aver- age daily gain, 65 0.81 0.82 0.74 0.70 Pounds Pounds feed dry consumed matter per 100 per 100 pounds pounds gain gain 480 472 453 514 517 433 427 465 467 * Cod-liver oil fed at the rate of 10 cc per pig per week. t The feed was first mixed; then enough for each feeding was soaked in water for 24 hours before being ed. fluid skim milk and skim-milk powder manufactured by the drum and spray processes. In manufacturing skim-milk powder, heat is used which might injure the feeding value. Table 3 gives the results. An attempt was made to feed the same percentage of protein in the form of fluid skim milk in lot 1 and of the dry product in lots 2, 3, and 4. As table 3 reveals, the pigs fed fluid skim milk gained faster and used less feed for a unit of gain than those fed the dried product. They made a pound of gain on less than 3 pounds of dry matter. Those given the spray-process product gained faster than those fed the drum-process dried powder (lots 2 and 3). The pigs in lot 4 fed drum-process skim- milk powder, damaged by a slight scorch, gained less efficiently than those of the other groups. Bul. 6Q§] Protein Supplements in the Feeding of Pigs 7 Experiment 4. — This trial, made in the summer of 1939, was designed to check part of experiment 3 and to determine whether the effect would be beneficial if the skim milk were reconstituted by returning the water that had been taken out. Lot 1 checks very closely that of lot 1 in trial 3 (table 3). Gains, however, were less rapid as can be seen by the data in table 4, doubtless because the pigs were younger and smaller when the TABLE 3 Experiment 3 : Comparative Value of Fluid Skim Milk and Skim-Milk Powder Manufactured by the Drum and Spray Processes Ration constituents, expressed as percentages* Lot no. Num- ber of pigs Days on feed (aver- age)! Aver- age initial weight, pounds Aver- age final weight, pounds Aver- age daily gain, pounds Pounds feed consumed per 100 pounds gain Pounds dry matter per 100 pounds gain Barley, 76; salt, 1; calcium carbon- ate, 1 ; skim milk — 1 pound of con- centrates mixed and fed with 3 1 2 3 4 5 5 5 5 78.4 86.8 93.0 99.6 49.2 47.2 47.6 46.2 186.4 163 6 183.2 181.0 1.75 1.34 J 1 45 1.35 Barley, 245; ■ skim milk, 735 356 286 Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (drum 324 Barley, 76; salt, 1; calcium carbon- ate, 1 ; skim-milk powder (spray 356 379 325 Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (drum 345 * Cod-liver oil fed at the rate of 10 cc per pig per week. t "Days on feed" is an average figure because the pigs were removed from the experiment when they reached a weight of 180 pounds. t One pig developed dermatitis and did very poorly. experiment began. In this trial the results for lots 3 and 4 are similar except that the pigs fed spray-process skim-milk powder gained faster. Comparing lots 2 and 3, we note a difference in favor of the pigs in lot 2. The only difference in these two lots is that the skim milk was reconsti- tuted (enough water was added to make it the same composition as fluid skim milk) in lot 2, and, of course, the ration was fed wet. The pigs gained faster in lot 2 and utilized the feed slightly more efficiently. Whey powder was fed to the pigs in lot 5 at the same level as skim-milk powder was fed in lots 2, 3, and 4. The pigs gained less rapidly and required considerably more feed per 100 pounds of gain than those of the other lots. 8 University of California — Experiment Station Experiment 5. — In this experiment, carried out in the summer of 1940, drum-process and spray-process skim-milk powder was compared with the same products reconstituted; also riboflavin was added to a ration of barley, casein (purified), salt, and calcium carbonate, to de- termine whether barley in the quantity fed contained enough of this TABLE 4 Experiment 4 : Check on Part of Experiment 3 and Effect of Eeconstituting Skim-Milk Powder Ration constituents, expressed as percentages* Lot no. Num- ber of pigs Days on feed Aver- age initial weight, pounds Aver- age final weight, pounds Aver- age daily gain, pounds Pounds feed consumed per 100 pounds gain Pounds dry matter per 100 pounds gain Barley, 76; salt, 1; calcium carbon- ate, 1; skim milk— 1 pound of con- centrates mixed and fed with 3 pounds of skim milk Barley, 76; salt, 1; calcium carbon- ate, 1 ; skim-milk powder (drum process), 22 — with 2.1 pounds of water added to each pound of 1 2 3 4 5 5 5 5 5 5 105 105 105 105 105 35.2 36.8 35.6 35.6 35.6 198.8 195.8 171.6 190.4 152.8 1 56 1.51 1.30 1.47 1.12 (Barley,) 239; | < skim > 1 milk.. 1 717 J 314 329 330 358 279 285 Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (drum process) ,22 299 Barley, 76; salt, 1; calcium carbon- ate, 1 ; skim-milk powder (spray • process) , 22 302 Barley, 76; salt, 1; calcium carbon- ate, 1 ; whey powder, 22 327 Cod-liver oil fed at the rate of 10 cc per pig per week. factor for the pig. As in experiment 4, the feeds to which water was added gave the better results. Pigs in lots 2 and 4 gained more rapidly and consumed less feed for 100 pounds of gain than those of lots 1 and 3. The pigs in lots 5 and 6 (table 5) received the same ration except that riboflavin was added in lot 6. Since there was no difference in the re- sults, the barley fed probably contained enough riboflavin for these pigs. The addition of casein at a 2.5 per cent level in lots 5 and 6 resulted in a rate of gain of 1.25 pounds per head daily — practically twice the rate for the pigs fed barley with no protein supplement (experiments 1 and 2). Bul. 663] Protein Supplements in the Feeding of Pigs 9 Experiments Where Tankage and Fish Meal Were Used. — Hogs fed barley were compared with those fed barley supplemented with tankage, fish meal, and fish meal to which stick was added. To supply vitamin A in some of the trials, alfalfa meal was added while in others cod-liver oil was given at the rate of 10 cc per pig weekly. The tankage used was a TABLE 5 Experiment 5 : Check on Part of Experiment 4 and Effect of Adding Riboflavin to the Ration Ration constituents, expressed as percentages* Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (drum process), 22 Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (drum process), 22— with 2.1 pounds of water added to each pound of concentrates fed Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (spray process), 22 Barley, 76; salt, 1; calcium carbon- ate, 1; skim-milk powder (spray process), 22— with 2.1 pounds of water added to each pound of concentrates fed Barley, 95; salt, 1; calcium carbon- ate, 1.5; casein (purified), 2.5. .. . Barley, 95; salt, 1; calcium carbon- ate, 1.5; casein (purified), 2. 5 — with 2 mg of riboflavin per 100 pounds of pig daily Lot no. Num- ber of pigs Days on feed 105 105 105 105 95 95 46. 57. 58.2 Aver- age final weight, pounds 192.0 193.6 201.4 177.0 176 2 Aver- age daily gain, pounds 1 36 1.40 1.34 1.48 1.26 1 24 Pounds feed consumed per 100 pounds gain 361 337 353 315 378 382 Pounds dry matter per 100 pounds gain 328 323 341 345 * Cod-liver oil fed at the rate of 10 cc per pig per week. standard 60 per cent protein product. The fish meal fed contained about 67 per cent protein. The stick, a dry residue from the water obtained from the fish, was mixed with the fish meal ; in protein content it resem- bled fish meal. The results of three experiments are summarized in table 6. The begin- ning weights of the pigs in lots 1 to 5 are similar although those in lot 1 were somewhat lighter than those of the other groups. Barley unsupple- mented with a protein concentrate resulted in about half the rate of 10 University of California — Experiment Station TABLE 6 Barley Supplemented with Tankage, Fish Meal, and Fish Meal Plus Stick* Ration constituents, expressed as percentages Barley, 97.5; salt, 1 ; calcium carbon- ate, 1.5. t (Average of two experi- ments.) Barley, 88; salt, 1; calcium carbon- ate, 1; tankage, 7; stick, 3t Barley, 88; salt, 1; calcium carbon- ate, 1 ; tankage, 10t Barley, 88; salt, 1; calcium carbon- ate, 1 ; fish meal, 10f Barley, 88; salt, 1; calcium carbon- ate, 1; fish meal, including stick, 10§t Barley, 88; salt, 1; calcium carbon- ate, 1 ; tankage, 10 Barley, 83; salt, 1; calcium carbon- ate, 1 ; tankage, 10; alfalfa meal, 5 . Barley, 88; salt, 1; calcium carbon- ate, 1 ; fish meal, 10 Barley, 83 ; salt, 1 ; calcium carbon- ate, 1 ; fish meal. 10; alfalfa meal, 5 Barley, 88; salt, 1; calcium carbon- ate, 1; fish meal, including stick, 10§ Barley, 83; salt, 1; calcium carbon- ate, 1; fish meal, including stick §, 10; alfalfa meal, 5 Lot no. Num- ber of pigs Days on feed 109.5J 95.4| 105.0 105.0 105.0 60.0 60.0 60.0 60.0 60.0 60.0 Aver- , age initial weight, pounds 41. 47 2 46.2 99.0 98. Aver- age final weight, pounds 110.8 174.4 176. 182.4 215. 210.0 211.2 204. 222.2 205.6 Aver- age daily gain, pounds 0.63 1.25 .22 1 24 1.30 1.94 1.85 1.87 1.76 2 05 1.78 Pounds feed consumed per 100 pounds gain 488 367 380 355 373 371 365 374 354 374 Pounds dry matter per 100 pounds gain 440 331 343 333 321 336 335 330 338 320 338 • Stick is a dry residue of the water obtained from the fish, t Cod-liver oil fed at the rate of 10 cc per pig per week. X This is an average figure because the pigs were removed from experiment when they reached the weight of 180 pounds. § This product was a mixture of fish meal, 85 per cent, and stick, 15 per cent. gain made on rations supplemented (lot 1 compared with lots 2 to 5). The amount of feed required for 100 pounds of gain was much greater. In these experiments a protein supplement resulted in saving over 100 pounds of barley for each 100 pounds of gain. Judging from a compari- son of lots 2 to 5, the addition of stick (lots 2 and 5) was of some benefit Bul. 66$] Protein Supplements in ttie Feeding of Pigs 11 because the amount of feed required for gains was less than for the other rations, and the rate of gain was slightly faster. According to the data comparing the results of lots 6, 8, and 10 with those of lots 7, 9, and 11, the addition of alfalfa was of no apparent value. Since, however, these pigs were on feed only 60 days, probably no vitamin-A deficiency was demonstrated. The results for the pigs fed tankage and for those fed fish meal are similar (lots 6 to 9) . When stick was included in the diet (lots 10 and 11), particularly in lot 10, gains were more rapid and the feed consumed for a unit of gain was less than for any other lot. DISCUSSION AND SUMMARY Barley, unsupplemented with a protein concentrate, was less efficient for growth and fattening than the other rations fed. Feeding casein at low levels (1.5 per cent) resulted in increased rates of gain, and the pigs consumed less feed for a unit of gain than those fed barley unsupple- mented. When casein was fed at a 2.5 per cent level, the rate of gain was increased over those lots fed this product at a 1.5 per cent level. In ex- periment 1 there was no difference between the value of commercial and purified casein, and in experiment 5 the results were practically identical when purified casein was compared to purified casein to which pure ribo- flavin (lots 5 and 6) had been added. Apparently, then, the barley fed in these experiments contained enough of riboflavin for the needs of the pigs. Whey powder fed at a 3.5 or 22.0 per cent level brought increased gains over the pigs fed barley with no protein supplement. Their gains were, however, far below those of pigs receiving fluid skim milk. When skim-milk powder comprised 3.5 per cent of the ration, the value was similar to that of rations in which casein comprised 1.5 per cent. Skim milk was fed in various ways, both fluid and dry. Dried skim milk, injured in manufacture, was the least efficient. Spray-process skim-milk powder seemed slightly superior to the product dried on a drum. Skim milk reconstituted by the addition of water to the dried product and then fed with barley produced better results than the same feed when given dry. In none of the experiments did the pigs do so well as on a ration of barley supplemented with salt, calcium carbonate, vita- min A (this factor was furnished in the form of cod-liver oil), and fluid skim milk. The addition of alfalfa meal in a short feeding experiment did not show an advantage. In experiments of short duration, pigs often fail to show a deficiency of vitamin A. When, however, young growing pigs are fed diets deficient in vitamin A over a long period (50 days or more) , 12 University of California — Experiment Station 1 liey do not make normal gains. Although no advantage is shown in these experiments, it is considered good practice to feed alfalfa meal in dry lot or to provide green pasture as a preventive against a possible vitamin- A deficiency. The addition of stick to fish meal resulted in some advantage, as is shown by the rapid and economical gains made by the pigs in lot 10 (table 6). 15m-l,'42(7346)