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Possibilities of increasing the use of forage and roughage in swine production

Illinois Agricultural Experiment Station

Abstract

Almost from the beginnings of this nation the chief contribution of swine to American agriculture has been their ability to convert concentrates into pork products, and efforts to improve

swine as a race have been developed largely toward increasing this capacity. It now appears that development in this direction may have gone too far and that if swine are to maintain their present position among the farm animals of the country efforts will have to be made to increase their capacity to consume roughages.

First, probably it should be made clear that forage, whether fed as hay or in the fresh state, to be of much value to pigs should be fine-stemmed and leafy, tender and succulent, and contain much protein and little fiber.

At the present time the use of dried roughages in the rations of producing swine is limited to the legume hays of good quality used in small amounts largely for their protective properties with no thought of their replacing concentrates. Ample experimental justification for this use of roughages is available. That somewhat more legume hay than this (possibly even as much as one-fourth of the ration) can be fed to fattening pigs without seriously handicapping their production is suggested by a rather extensive study that was made at the Nebraska Station some 25 years ago.

A wider use is made of legume hays in the ration of sows during gestation than elsewhere in swine feeding. From the standpoint alone of protection for the sow its use here is by no means as nearly universal as it might well be. Some observations that are probably not entirely legendary report that sows have been brought through the winter gestation period in reasonably satisfactory farrowing condition with no feed other than first class alfalfa hay. I know of no experiments that have gone this far.

Pasture crops are used in the rations of fattening pigs more frequently and more extensively than hays. The contribution that pasture makes to the ration decreases as the ration aside from pasture becomes more nearly complete nutritionally. This, of course, is what would be expected and is well demonstrated by a chronologic study of pasture tests. In the days when corn was fed without supplement good pasture brought about a remarkable increase in gain, especially in young pigs, and accounted for a large saving of corn. The results of feeding a ration of corn and tankage on pasture rather than in dry lot are less striking both in the increase in rate of gain and in the amount of feed saved. Finally, a number of tests have recently been reported in which even very light pigs fed in dry lot have gained as rapidly as, and consumed no more total concentrates than similar pigs did that were fed the same ration on good pasture.

Attempts to utilize pasture more extensively than this by restricting the concentrate intake of pasture-fed pigs have not been uniformly successful. In fact, restricting the feed intake has, almost as frequently as not, increased rather than decreased the feed eaten for unit of gain made. Under present marketing conditions spring pigs (unless farrowed extremely early) that are fed a limited ration on pasture are confronted with a genuine handicap when they reach market because by this time the price has usually declined materially from the point it reached a few weeks earlier.

There is one direction in which the use of pasture might possibly be expanded, apparently with profit to many farms. Reference is made to the use during late fall and early spring of fallsown rye in northern latitudes and of other suitable crops farther south. At the Illinois Station the grazing season has for several years been lengthened fully six weeks in the spring by the use of rye. Last year a test, conducted as a graduate problem by Mr. Wise Burroughs, indicated that rye pasture may be a worthwhile addition to the ration of fall pigs at least during the early part of their fattening period. During the first 56 days of the test a given concentrate intake on rye pasture produced 27 percent more gain than when fed in dry lot. Other pigs on rye pasture that were fed to gain at the same rate as the pigs in dry lot required during the first 56 days of the test 22 percent less of the feed mixture for an equal gain. From this point on there was less difference between the two methods of feeding either because the pigs as they became heavier were in less need of the nutrients that were contained in the green rye and not in the concentrate, or because severe weather reduced grazing, or finally because the rye became less accessible due to the presence of an unusual amount of snow and ice.

As in the feeding of hay, pastures find a wider use with brood sows than with fattening pigs. At least half the grain required by sows during gestation can be saved if good pasture is provided. In fact, mature sows that begin gestation in reasonably good condition can be carried through this period without concentrates if an abundance of good forage is available. A few years ago eight sows were so carried on an acre of alfalfa at the Illinois Station.

Obviously, the safe thing to do is to keep this discussion at least within hailing distance of experimental results. The results, however, have largely been exhausted before much increase in roughage consumption has been achieved. May I, therefore, suggest certain possibilities and relationships that have not been investigated, doubtless because under prevailing conditions there has been no incentive.

If swine are expected to continue to yield much the same products they now produce and do this on a ration that contains more roughage than they now consume, it would appear necessary to return to the very chuffy type of earlier days. Any very large increase in the proportion of roughage in the ration of fattening pigs will almost certainly retard gains. With the type of pig most frequently encountered these days slow gains mean lack of finish at market weights now considered desirable. The stronger tendency to lay on external fat that is found in the thicker made pig may even in face of slow gains produce sufficient fat to make a desirable carcass at moderate weights.

An alternative would be to carry the pigs to a much heavier weight before slaughter. This undoubtedly would tend to increase the depth of fat covering on the carcass but the consuming public would need to be educated to accept lean cuts of very different character from those to which it is now accustomed.

Finally, of course, the well known plasticity of the pig in the hands of the breeder may be brought into the consideration. Great as this is, it does not appear at all likely that even the present search will reveal germ plasm sufficiently "superior" to change the pig to a ruminant. It may be within the range of human effort, however, to improve greatly the grazing capacity of swine in case changes in crop production should make this desirable.

This suggests an even more radical possibility; namely, a fundamental change in the kind of product produced by the pig. It is probable that the fat now produced for the American diet by the pig (except for bacon) can be more cheaply and just as satisfactorily supplied from other sources. If so, this presents to the swine breeder the possibility of making the hog primarily a lean meat producing animal rather than one that is raised largely for the fat of its carcass. Such a change might conceivably be made without sacrificing entirely the bacon belly in its present form.

The American corn crop is given credit for greatly increasing the ability of pigs to store fat in the body cavity and on the back—in other words, for producing the lard-type hog. Theoretically, at any rate, it should be possible to reverse the process and besides eliminating the excess storage of fat that has been built up in the lard-type hog, probably greatly reduce fat storage internally and on the back without losing the necessary thickness in the belly region.

It is my personal belief that even though the changes suggested may be possible of accomplishment, the American hog will yield a great deal of ground to roughage consuming animals before he will modify greatly his present mode of life.