University of Missouri Extension

G2350, Revised August 1982

Meeting the Protein and Amino Acid Needs of Swine

John C. Rea
Department of Animal Science

All pigs require protein, which consists of amino acids. Amino acids are used for maintenance, growth, gestation, and lactation. Pigs actually do not have a protein requirement, but quality protein provides the amino acids which are required. While some amino acids are synthesized by the animal, the essential ones cannot be synthesized at a rapid enough rate to permit normal growth. These must be provided in the feed. See Table 1 for the essential amino acids and their requirements for growing and finishing pigs.

Table 1
Protein and amino acid requirements for growing pigs and sows.1

  Growing pigs Sows
  Pounds 25 to 50 50 to 75 75 to 125 125 to 225 Gestation Lactation
Protein 18 16 14 13 12 13
Arginine .23 .20 .18 .16 .0 .40
Histidine .20 .18 .16 .15 .15 .25
Isoleucine .56 .50 .44 .41 .37 .39
Leucine .68 .60 .52 .48 .42 .70
Lysine .79 .70 .61 .57 .43 .58
Methionine + cystine2 .51 .45 .40 .30 .23 .36
Phenalanine + tyrosine3 .79 .70 .61 .57 .52 .85
Threonine .51 .45 .39 .37 .34 .43
Tryptophan .13 .12 .11 .10 .09 .12
Valine .56 .50 .44 .41 .46 .55
1NRC. 1979. Nutrient Requirements of Swine.
2Methionine can fulfill the total requirement; cystine can meet 50 percent of the total requirements.
3Phenalanine can fulfill the total requirement; tyrosine can meet 50 percent of the total requirements.

During digestion, protein breaks down into individual amino acids. The animal then absorbs amino acids from the intestines. Then, the amino acids are recombined within the body tissue into new protein molecules. When you formulate swine diets, keep in mind that most cereal grains are deficient in lysine, tryptophan and threonine. Lysine is commonly the most limiting amino acid. Evaluate protein sources primarily on the ability to correct these deficiencies, particularly that of lysine. See Table 2 for the approximate contents of some of the more important amino acids in common feeds.

Table 2
Essential amino acid content of commonly used swine feeds.1

  Protein Arginine Histidine Isoleucine Leucine Lysine Methionine Cystine Phenylalanine Tyrosine Threonine Tryptophan Valine
  Percent
Grains
Corn 8.8 .42 .24 .31 .98 .26 .19 .20 .41 .35 .32 .09 .46
Sorghum 9.0 .36 .21 .38 1.13 .22 .17 .14 .46 .37 .29 .09 .70
Barley 11.7 .58 .27 .54 .81 .36 .18 .19 .63 .36 .36 .16 .63
Corn, high lysine 8.5 .53 .28 .27 .70 .37 .16 .18 .35 .27 .31 - .41
Oats 12.0 .58 .15 .39 .66 .34 .18 .15 .39 .60 .33 .13 46
Wheat 12.2 .60 .28 .46 .88 .38 .20 .16 .62 .38 .37 .15 .55
Protein Sources
Soybean meal 44 3.20 1.21 2.32 3.62 2.88 .56 .66 2.35 1.46 1.87 .55 2.31
Soybean meal 50 3.54 1.30 2.49 3.88 3.14 .73 .82 2.52 1.56 2.00 .63 2.48
Alfalfa meal, dehydrated 17 .94 .29 .72 1.09 .80 .29 .29 .72 .43 .58 .36 .80
Blood meal 80 3.20 3.79 .88 9.89 5.37 1.04 1.40 5.17 1.78 3.87 1.02 6.91
Buttermilk, dry 32 1.08 .80 2.17 3.13 2.20 .72 .41 1.43 1.01 1.46 .47 2.40
Cottonseed meal, solvent 41 4.27 1.00 1.18 2.12 1.55 .49 .65 1.96 1.03 1.19 .48 1.60
Distillers dried solubles (corn) 27 1.03 .70 1.72 2.21 .77 .50 .36 1.72 .61 1.01 .18 1.61
Fish meal (menhaden) 60 4.06 1.55 2.99 4.79 4.60 1.88 .62 2.65 2.14 2.67 .71 3.42
Meat and bone meal 50 3.59 .90 1.71 3.12 2.50 .65 .62 1.81 .84 1.81 .29 2.42
Peanut meal, expeller 50 5.23 .94 1.47 2.62 1.35 .54 .34 2.17 1.72 1.13 .48 2.72
Tankage (meat meal) 60 3.69 1.95 1.95 5.26 3.89 .75 .52 2.78 .96 2.48 .58 4.32
Wheat bran 15 .95 .29 .56 .85 .56 .09 .29 .47 .38 .38 .29 .66
Wheat midds, standard 16 .83 .37 .73 1.10 .64 .16 .18 .63 .37 .54 .18 .73
Whey, dried whole 12 .27 .16 .72 1.00 .80 .16 .24 .28 .16 1.03 .13 .56
Yeast, brewers dried 45 2.22 1.11 2.12 3.23 3.02 .71 .50 1.82 1.52 2.12 .50 2.31
1Pork Industry Fact Sheet, 5

Sources of protein supplement
Soybean meal does an excellent job of supplementing cereal grains to meet the amino acid requirements of pigs. Other protein sources can be successfully included in the swine ration depending on their cost and quality.

There are limitations to the amounts you should add to the swine rations. These limitations have to do with palatability, levels of amino acids, and price. For example, you should limit meat meal to 40 to 50 percent of the total supplement, and cottonseed meal to 10 to 15 percent of the total supplement. Although meal is an excellent protein source, it is often limited because of cost.

Calculating grain protein ratios
Use Table 3 as a quick way to determine the approximate ratio of grain and supplement needed to provide a given protein level. For example, if you need a 16 percent ration for 50- to 75-pound pigs, and if you are using a 32 percent commercial supplement, Table 3 shows that 1,392 pounds of corn and 608 pounds of supplement are required to make up a ton of 16 percent total ration. Thus, you need 2.28 pounds of grain for each pound of supplement. If the supplement was 44 percent soybean meal, the ratio would be 4 pounds of grain to 1 pound of the 44 percent supplement.

Table 3
Grain-supplement ratios for different swine rations. Shows the amount of supplement needed at different percent levels to formulate 2.000 pounds of ration with different levels of protein. (Shelled corn figured at 9 percent protein.)

Percent protein in supplement Percent protein in total ration
12 13 14 15 16 18 20 22
30 grain (pounds) 1,714 1,620 1,524 1,428 1,334 1,144 952 762
supplement (pounds) 286 380 476 572 666 856 1,048 1,238
pound of grain per pound of supplement* 6.00 4.25 3.20 2.50 2.00 1.33 0.91 0.62
31 grain (pounds) 1,728 1,636 1,546 1,454 1,364 1,182 1,000 818
supplement 272 364 454 546 636 818 1,000 1,182
pound of grain per pound of supplement 6.33 4.50 3.40 2.67 2.14 1.44 1.00 0.69
32 grain 1,740 1.652 1,566 1,478 1,392 1,218 1,044 870
supplement 260 348 434 522 608 782 956 1,130
pound of grain per pound of supplement 6.67 4.75 3.60 2.83 2.28 1.56 1.09 0.77
33 grain 1,750 1,666 1,584 1,500 1,416 1,250 1,084 916
supplement 250 334 416 500 584 750 916 1,084
pound of grain per pound of supplement 7.00 5.00 3.80 3.00 2.43 1.67 1.18 0.85
34 grain 1,760 1,680 1,600 1,520 1,440 1,280 1,120 960
supplement 240 320 400 480 560 720 880 1,040
pound of grain per pound of supplement 7.33 525 4.00 3.17 2.57 1.78 1.27 0.92
35 grain 1,770 1,692 1,616 1,538 1,462 1,308 1,154 1,000
supplement 230 308 384 462 538 692 846 1,000
pound of grain per pound of supplement 7.67 5.50 4.20 3.33 2.71 1.89 1.36 1.00
36 grain 1,778 1,704 1,630 1,556 1,482 1,334 1,186 1,036
supplement 222 296 370 444 518 666 814 964
pound of grain per pound of suppL 8.00 5.75 4.40 3.50 2.86 2.00 1.45 1.08
37 grain 1,786 1,714 1,642 1,572 1,500 1,356 1,214 1,072
supplement 214 286 358 428 500 644 786 928
pound of grain per pound of supplement 8.33 6.00 4.60 3.67 3.00 2.11 1.54 1.15
38 grain 1,792 1,724 1,656 1,586 1,518 1,380 1,242 1,104
supplement 208 276 344 414 482 620 758 896
pound of grain per pound of supplement 8.67 6.25 4.80 3.83 3.14 2.22 1.64 1.23
39 grain 1,800 1,734 1,666 1,600 1,534 1,400 1,266 1,134
supplement 200 266 334 400 466 600 734 866
pound of grain per pound of supplement 9.00 6.50 5.00 4.00 3.28 2.33 1.73 1.31
40 grain 1,806 1,724 1,678 1,612 1,548 1,420 1,290 1,162
supplement 194 258 322 388 452 580 710 838
pound of grain per pound of supplement 9.33 6.75 5.20 4.17 3.43 2.44 1.82 1.38
41 grain 1,812 1,750 1,688 1,624 1,562 1,438 1,312 1,188
supplement 188 250 312 376 438 562 688 812
pound of grain per pound of supplement 9.67 7.00 5.40 4.33 3.57 2.56 1.91 1.46
42 grain 1,818 1,758 1,696 1,636 1,576 1,454 1,334 1,212
supplement 182 242 304 364 424 546 666 788
pound of grain per pound of supplement 10.00 7.25 5.60 4.50 3.71 2.67 2.00 1.54
43 grain (pounds) 1,824 1,764 1,706 1,648 1,588 1,470 1,352 1,236
supplement (pounds) 176 236 294 352 412 530 648 764
pound of grain per pound of supplement 10.33 7.50 5.80 4.66 3.86 2.78 2.09 1.62
44 grain (pounds) 1,828 1,772 1,714 1,656 1,600 1,486 1,372 1,256
supplement (pounds) 172 228 286 344 400 514 628 744
pound of grain per pound of supplement 10.67 7.75 6.00 4.83 4.00 2.88 2.18 1.69
45 grain (pounds) 1,834 1,778 1,772 1,666 1,612 1,500 1,388 1,278
supplement (pounds) 166 222 278 334 388 500 612 722
pound of grain per pound of supplement 11.00 88.00 6.20 5.00 4.14 3.00 2.27 1.77
50 grain (pounds) 1,854 1,804 1,756 1,708 1,658 1,560 1,464 1,366
supplement (pounds) 146 196 244 292 342 440 536 634
pound of grain per pound of supplement 11.33 9.25 7.20 583 4.86 3.56 272 2.15
*Corn-supplement ratio

Buying protein supplement wisely
In general, as the percentage of protein increases in a supplement, price per pound of protein decreases. However, price is not the only factor to consider when buying protein. A quality or balance of amino acids and other factors should also be considered. Also commercial supplements often contain minerals, vitamins, and may contain antibiotics and medicants for use with home-grown grains. These add to the cost of the ration. Consider these costs when comparing the complete supplement price with soybean meal. Have a general idea of the total cost of these nutrients per ton of feed so you can more accurately compare the costs of home-mixed and commercial supplements.

Keep in mind, however, in comparing sources of protein that the major nutrient you're purchasing is protein. A good method of making a cost comparison is on the basis of cost per pound of protein

Table 4 allows you to make quick comparisons of two supplements or a comparison with soybean meal.

Table 4
Cost per pound of protein at various percentages and prices.

Price of supplement per ton Cost of 1 pound of protein when percentage of protein is
20 percent 25 percent 30 percent 35 percent 40 percent 45 percent 50 percent
Cents Cents Cents Cents Cents Cents Cents
$160.00 40.00 32.00 26.66 22.86 20.00 17.78 16.00
$165.00 41.25 33.00 27.50 23.57 20.62 18.33 16.50
$170.00 42.50 34.00 28.33 24.29 21.25 18.89 17.00
$175.00 43.75 35.00 29.17 25.00 21.88 19.44 17.50
$180.00 45.00 36.00 30.00 25.71 22.50 20.00 18.00
$185.00 46.25 37.00 30.83 26.42 23.12 20.56 18.50
$190.00 47.50 38.00 31.67 27.14 23.75 21.11 19.00
$195.00 48.75 39.00 32.50 27.88 24.38 21.67 19.50
$200.00 50.00 40.00 33.33 28.57 25.00 22.22 20.00
$205.00 51.25 41.00 34.17 29.29 25.62 22.78 20.50
$210.00 52.50 42.00 35.00 30.00 26.25 23.33 21.00
$215.00 53.75 43.00 35.83 30.71 26.88 23.89 21.50
$220.00 55.00 44.00 36.67 31.42 27.50 24.44 22.00
$225.00 56.25 45.00 37.50 32.14 28.12 25.00 22.50
$230.00 57.50 46.00 38.33 32.88 28.75 25.56 23.00
$235.00 58.75 47.00 39.17 33.57 2938 26.11 23,,50
$240.00 60.00 48.00 40.00 34.29 30.00 26.67 24.00
$245.00 61.25 49.00 40.83 35.00 30.62 27.22 24.50
$250.00 62.50 50.00 41.66 35.71 31.25 27.78 25.00
$255.00 63.75 51.00 42.50 36.42 31.88 28.33 25.50
$260.00 65.00 52.00 43.33 37.14 32.50 28.89 26.00
$265.00 66.25 53.00 44.16 37.88 33.12 29.44 26.50
$270.00 67.50 54.00 45.00 38.57 33.75 30.00 27.00

Use of synthetic amino acids
Researchers have clearly demonstrated that supplemental lysine can significantly reduce the amount of high quality soybean meal needed. Be aware of the price per unit of lysine in the synthetic sources as compared to the natural source. With the use of synthetic lysine, you can decrease the dietary protein level without affecting performance. As a rule, 3 pounds of lysine monohydrochloride plus 97 pounds of grain can replace 100 pounds of 44 percent soybean meal. If the supplemental lysine plus the grain is cheaper than 44 percent soybean meal, the cost of the diet can be reduced by using supplemental lysine.

High lysine corn
Opaque-2 corn is higher in lysine and tryptophan than regular hybrid corn, but its protein level is similar to regular corn. You can balance rations successfully on the actual lysine content of high amino acid grain. Have an analysis taken since there is considerable variation among high lysine varieties. Make decisions concerning the use of Opaque-2 corn in swine rations on the basis of economics, yield characteristics, and lysine content of the particular variety available.

 

G2350 Meeting the Protein and Amino Acid Needs of Swine | University of Missouri Extension

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