Swine Nutrition

Swine Processing Articles >> Feed & Nutrition

In approaching the problem of swine nutrition we must keep in mind the fact that swine production constitutes one of the main items in the agricultural economy of Canada. The status of the industry varies in the different Provinces but by and large revenue from swine contributes substantially to farm spending power and plays a significant part in connection with determining the standard of living which prevails on a considerable percentage of the farms of this Dominion. During our peak year of 1944 swine marketings accounted for a gross revenue of approximately $225,000,000 and, on the basis of our present volume of production and prevailing prices, we may expect a return of around $175,000,000 from this phase of our agriculture. Having in mind the revenue aspect together with the importance of meat supplies in connection with good human nutrition it is clear that the swine business is one that justifies careful study from all angles.

The figures quoted above refer to the gross returns on swine raising. The difference between these figures and the cost of producing the pig crop represents the net return or the actual profit to the farmers on the pig raising enterprise. Continuity of production and stability in the pig business depend- upon net returns and these in turn are dependent upon the relation between selling price per hundredweight and the cost of production per hundredweight. The margin between these figures is never great and in times of depressed prices is very narrow or nonexistent. Since no effective means have been developed to raise the selling price beyond certain levels we are thrown back -on the proposition that the only means which the swine producer has within his own grasp, so far as widening the margin is concerned, is lowering the cost of production.

While a number of items enter into the cost of producing a marketable hog the most significant and perhaps the most variable is the cost of feed. It follows then that special attention must be given to swine nutrition and in this connection such matters as volume of feed supply, quality of the basic feeds (cereals), quantity and quality of supplemental feeds, blending of the various ingredients, and recommendations regarding feeding procedure all require proper consideration.

What is back of this job of swine feeding or swine nutrition? It is the business of converting grain and by-products into a highly edible human food. It is a big business. If we regard the process as one of tying forty bushels of grain into a burlap wrapper ready for export into Britain in the form of four Wiltshire sides or, to put it in another way, walking twenty bushels of barley to market in the form of a market hog, we can grasp more 'fully the true nature of'the undertaking. Looking at it in this way we see that our 1947 pig crop will market approximately 100,000,000 bushels of grain and, on the same basis, the 9,000,000 pigs which we marketed in 1944 converted about 180,000,000 bushels of grain into pork products. This type of calculation focuses attention on grain supplies and the significance of grain prices in relation to the farmer's attitude toward pig raising at any given time. The primary motive in producing pigs on the average farm is that of marketing grain at a higher price than it can be sold 'for on the cash grain market or increasing its value if it has to be purchased if not available as home grown grain. Disturbance in continuity of production develops when doubt arises in the mind of the farmer as to his chances of increasing the value of the grain by feeding it to pigs at least to the point where he will secure a fair return on the labor expended. The farmer'then is the one who has the greatest interest in swine nutrition and it is he who will reap the greatest benefit from the application of the best knowledge that is available in this field.

But there are many others who have an interest and responsibility in this matter. The experimentalist is charged with the responsibility of studying the basic nutritional requirements of the pig, of investigating the composition and feeding value of the various ingredients suitable for swine feeding, and of determining the manner in which feeds react when blended in varying proportions. The job of the nutritionist is to determine the requirements of the pig in terms of the various nutritional factors and establish combinations of feeds which will enable the pig to function efficiently and economically in the production of pork. The extension worker is concerned with developments in swine nutrition since it is his job to relay to the farmer the. most up-to-date information regarding feeding practices. The feed manufacturer and distributor is interested because he is concerned with the disposal of by-products either in an original form or blended with others and sold as supplements or mixed with grains and distributed as complete rations. He is in the picture as a blender and mixer of feeds and the success of his undertaking depends upon the application of sound nutritional principles since the test of his swine rations is performance in the piggery. The veterinary scientist is very much involved in matters of swine nutrition since many of the "disease conditions" which come to his attention are of nutritional origin either directly or indirectly. Good performance in the swine herd from the nutritional angle therefore depends upon an adequate supply of good basic feeds, continual research on swine nutrition problems. the application of the latest scientific information in connection with the blending and processing of fe'eds, and close liaison in the fields of animal nutrition and veterinary science.

Nutrition cannot of course be separated from other features contributing to. the welfare of the swine industry. The importance of breeding cannot be overlooked and the place of management practices in relation to success in swine raising looms large. Indeed, many of our present day swine nutritional problems have arisen as a result of chaniges in swine raising methods. The trend in the direction of closer housing in an attempt to improve the quality of the ultimate product and to extend the farrowing season has brought with it many complications from the nutritional standpoint. Placing the pig on concrete floors and removing him from soil, pasture, and sunlight has made him dependent upon the science of animal nutrition. His native instinct to ferret out the missing factor in his diet is curbed when a plan of close confinement is adopted. He is dependent upon what is placed before him by the feeder. Many of the most glaring cases of nutritional deficiencies have developed when modern piggeries have been erected and their use has not been accompanied by the feeding of completely balanced rations.

Mention was made earlier of the importance of feeding in relation to cost of production. Proper nutrition affects economy of production in a number of different ways. The following may be mentioned:-

(1) Rate of Gains-One means of determining the efficiency of a ration is to note the effect on rate of growth. Rapid gains are usually accompanied by economical gains but apart from this the number of days required following birth to place a pig on the market is significant from the farmer's point of view. Each day the pig is on the farm he calls for a certain amount of service in the form of labor. Any ration or system of feeding that slows down the rate of growth leads to an increase in labor cost and the net return is reduced accordingly. In our swine feeding experiments at the University of Alberta, differences in time required to reach market weight as a result of balanced and unbalanced rations have been brought out clearly. It has been said that time means nothing to a pig but under present conditions of labor scarcity time means much to the swine feeder.
(2) Economy of Feed Utilization-Since feed is the main factor in determining the cost of swine production it is clear that every effort must be made to reduce the number of pounds of feed required to produce a marketable pig to the lowest possible figure. The strong argument in favor of the use of properly blended and balanced rations lies in the fact that the complete feed enables the pig to function efficiently as a bacon producing machine. The saving per individual pig may not loom large, although it could be of the order of two or three hundred pounds or even more, but when applied to the total output of a farm or of the whole country the saving would be substantial. Apart from the effect on the economic returns on any given swine feeding enterprise, the saving of grain is important from a broader aspect which becomes increasingly apparent during times of world-wide food shortage. Converting grain into meat is an extravagant process from the standpoint of providing calories. It should only be done with a minimum outlay of grain.
(3) Deficiency Diseases-There are several deficiency conditions which are traceable to a lack of some essential element in the ration. In Alberta, for example, serious difficulty is encountered with crippling, particularly in winter pigs. The addition of calcium to the ration has relieved or prevented most of these cases. Anemia is one of the most important causes of direct or indirect loss of young pigs. The. toll on the annual pig crop is heavy. Iodine deficiency leads to a heavy loss from hairless pigs each year. Protein deficiency causes unthrifty and stunted pigs and in many cases leads to complications which end in pig mortality. Vitamin A and vitamin- D shortages also account for losses in many cases.
(4) Amount and Quality of Finish-The importance of the ration in relation to the finish and quality of the carcass cannot be overlooked. Feeding cannot work miracles in determining the type of the finished carcass but it can exert an influence on the amount of finish and to some extent on the amount of lean in the carcass. So far as general type is concerned, experiments at the University of Alberta indicate that breeding is the main factor in determining such items as length, balance, uniformity of back fat, and other such characters. Underfinish and overfinish, however, can be affected by the ration or by a method of feeding so that the nature of the finishing ration must receive proper attention. It may be stated too that our investigations of several years ago into the causes of soft bacon led to the conclusion that unthriftiness at an early stage of growth, due to faulty rations, was an important contributing factor.

Tbe Basic feeds (Corn)
The supply of coarse grains and wheat together with the market value per bushel or per ton of each determines the attitude toward pig raising and to a considerable extent the proportions of the various grains which will be included in swine rations. Supply, of course, fluctuates with seasonal conditions and prices under present arrangements vary with contracts or modifications in government policy. Changes in the grainhog ratio create a lack of stability in the swine raising enterprise.

In connection with our swine experimental program we have devoted considerable time to a study of the various cereals from the standpoint of their suitability when fed singly and in varying proportions. Our Alberta grains have been found to vary rather widely in protein content depending upon the soil and climatic conditions under which they are grown. These variations have been significant in relation to the amount of protein supplement required to balance the ration and have led us to suspect that they may be responsible for variations in the efficiency of pig production in various parts of Alberta and between farms in a given area. Work done thus far on the quality of cereal protein indicates that differences in quantity of protein are not accompanied by differences in protein quality.

Some idea of our experience regarding the comparative value of the three common farm grains may be gained from a typical experiment in which the three grains were fed separately and on the basis of equal parts by weight. Tankage was fed as a supplement and a simple mineral mixture was fed free choice.

It will be noted from the above table that the pigs fed barley and wheat grew at about the same rate and more than one-tenth of a pound per day faster than those fed oats. Wheat proved the most e'fficient grain, followed by barley and then oats on the basis of pounds of feed required to produce 100 pounds live weight of pig. In this experiment the amount of gain produced by 100 pounds of ground oats was produced by 92 pounds of barley, 87 pounds of wheat, and 79 pounds of grain when the three were mixed. These values are in line with the usual determinations for total digestible nutrients of the cereals. The improvement brought about by the mixing process may have been due to improved palatability and to some chance supplementary influence.

On several occasions barley and wheat were compared with respect to their influence on amount of finish in the carcass and on general carcass quality. No significant differences were found in the results secured from the two grains in the major factors influencing carcass quality.

The Protein Problem
The major portion of the experimental work in swine nutrition at the University of Alberta over a period of twenty-five years has been centered on the protein problem. Attention was directed to this question as a result of the scarcity of dairy by-products available for supplementary feeding. Early experiments indicated that average grain samples failed to provide sufficient protein to insure satisfactory growth in pigs following weaning, and up to weights of from 110 to' 120 pounds, and did not induce adequate milk production in nursing sows.

Early attention was given to the use of tankage as a protein supplement and extension efforts with farmers encouraged the use of this source of protein, then in ample supply. As a result of the satisfactory results being secured with the early "trinity mixtur'e" being used in the United States in the "twenties" the blending of protein supplements was attempted and comparisons between tankage and various mixtures were undertaken. As supplies of animal protein became scarce, the addition *of larger amounts of 'plant proteins was tested. The stage of growth at which protein supplements might be reduced or eliminated was included as a matter for study and the influence of various levels of protein in the ration on carcass quality was given consideration.

No attempt will be made to elaborate on any individual experiment. It will be sufficient to state the following general conclusions:-

(1) The feeding of grain without protein supplements has led to unsatisfactory results. Gains have been poor, unthriftiness invariably developed, and the feed requirement per unit of gain has been high.
(2) The purchase of protein supplements has been economically sound. The swine in feed cost has been sufficient to pay the cost of supplements and additional credit has been received due to shortening the period required to put pigs on the market.
(3) The optimum level of protein feeding during the afterweaning stage has been 15% of' digestible crude protein.
(4) Satisfactory per'formance has been secured when protein supplements have been eliminated from the ration after pigs reached a weight of from 110 to 120 pounds although continuation of the feeding of protein feeds after that stage has led to improvement in rate-of growth and economy of production.
(5) Supplements containing as low as 30% tankage, together with 35% linseed oil meal and 25% alfalfa meal, have given satisfactory results when fed at levels insuring standard protein intake.
(6) The feeding of protein over and above optimum amounts has not led to any improvement in carcass quality as judged by the proportion of fat and lean.

The mineral problem
One of the first swine experiments at the University of Alberta was designed to study the cause of sows giving birth to hairless pigs. The condition was prevalent throughout the Province and was a source of serious losses. Very shortly after the initiation of these trials Montana workers demonstrated that iodine deficiency was responsible for the trouble and when tests were conducted to check the findings positive results were secured.

Crippling of pigs is a common cause of unthriftiness and loss among pigs in Alberta. The situation is particularly troublesome in winter raised pigs and what may be regarded as an "epidemic" is likely to become apparent during the month of February. Experiments were commenced using slaked lime as a source of calcium and later ground limestone has been utilized as a supplier of this mineral. Our results have shown that the most common cases of crippling are due to calcium deficiency and the condition has been prevented or relieved by the use of ground limestone when fed in the form of a mineral mixture or when included as an ingredient in combined protein and mineral supplements. Blood analyses in our own laboratories have shown that crippling has been accompanied by low blood calcium and that the addition of ground limestone to the ration of calcium deficient pigs has restored the calcium in the blood to normal levels.

Anemia continues to make a levy on the young pig population each year, particularly among those born during the late fall, winter, and early spring months. The young pig is the victim of artificial conditions of pig rearing. Our actual experiments with anemia have not been extensive but limited tests comparing reduced iron with the sod and iron sulphate treatment have led to the following conclusions:-

(1) By the end of the first week pigs not treated with iron showed a marked drop in. hemoglobin and by the third week typical symptoms of anemia developed in the majority of cases. Hemoglobin -remained low up to weaning time.
(2) Treatment with reduced iron prevented the development of acute anemia but it was noted that individual pigs varied widely in the hemoglobin content of their blood. The blood picture at seven weeks of age was generally unsatisfactory.
(3) The use of sods and iron sulphate as a means of preventing the development of anemia proved very satisfactory.

Our' observations lead us to believe that the last word has not been said regarding the prevention of anemia and the aftermath of complications which may develop following apparent recovery from the condition. Following our investigations on cobalt deficiency in sheep' it was thought well to determine whether or not growing pigs woixld respond to the administration of this element. Four experiments with pigs carried through from weaning time until they reached market weight failed to develop any evidence that cobart feeding was beneficial. It'was concluded that, if pigs require cobalt for their proper nutrition, the basic feeds used in the four experiments contained a sufficient trace to enable the pigs to grow and thrive satisfactorily.

The feeding of common salt to pigs has been shown to be definitely beneficial in our trials. An allowance of .5% of the ration has given maximum results.

Vitamins
Our experiments on the place of vitamins in swine nutrition have been somewhat general in nature and have centered on the improvement in performance resulting from exposure to sunlight or artificial irradiation, the feeding of cod liver oil, pilchard oil and blended fish oil, as well as alfalfa products. Results have been variable but the weight of evidence from a number of trials justifies the conclusion that growing pigs up to a weight of 100 pounds when fed inside the piggery benefit from the feeding of vitamin A and D carriers. The feeding of nicotinic acid (niacin) and riboflavin to growing pigs has not resulted in any improvement in performance in trials conducted thus far at the University of Alberta.

Reproduction
In view of the fact that few, if any, tests have been conducted in Canada to demonstrate the value of supplementary feeding of the sow in relation to farrowing performance it was decided in 1944 to initiate a test bearing on this point. Two groups of four sows were selected and placed on trial. One group was to receive a standard protein-mineral supplement with access to pasture in season and feeding oil (1500 A and 200 D per gram) at the rate of one ounce per day during pregnancy and the other group the same basal grain mixture with only 1% of salt and 1% of ground limestone added. The rations mentioned were fed during the suckling period and the young pigs in each group had access to the mothers' ration until weaned.

Gilts from the original sows in each group have been retained in the experiment and have been placed on the same rations as their mothers following breeding.

It is quite evident that the sows on the inadequate ration have farrowed a smaller percentage of live pigs and have made a poorer showing in terms of pigs weaned than those fed the supplemented ration.

Summary
By way of summary some of the more significant conclusions which may be drawn from our swine feeding experiments at the University of Alberta are the following:-

(1) The individual grains such as oats, barley, and wheat have been found to vary rather significantly in protein content, depending upon the soil and climatic conditions under which they have been grown. Good results have followed the mixing or blending of grains in swine rations.
(2) The feeding of grains alone without proper supplementation has led to disastrous results. Protein, mineral, and vitamin deficiency conditions have developed when such a procedure has been followed.
(3) The main limiting factor in the use of grain alone in the feeding of breeding stock and growing pigs has been a deficiency of protein and calcium.
(4) The feeding of protein supplements has led to improvement in rate and economy of gains and the purchase of such supplements has been an economically sound procedure.
(5) In connection with the mineral problem, definitely beneficial results have been obtained in the majority of experiments from the feeding of calcium in the form of ground limestone to growing pigs and brood sows, common salt to all classes of pigs, iodine to pregnant sows and iron in various forms as a preventive of anemia in suckling pigs.
(6) Vitamin A and vitamin D deficiency conditions are likely to develop under certain feeding and management arrangements unless such darriers of these vitamins as fish oils or alfalfa products are fed. No significant results have been secured thus far from the feeding of other vitamin factors.
(7) Feeding inadequate rations to brood sbws has resulted in poor performance in terms of size of litters, percentage of pigs weaned and after-weaning performance of the pigs.

In spite of the considerable amount of experimental work which has been carried out in swine feeding there are still a number of questions awaiting answers. As our pigs become more intensively bred and as pig production moves away farther from natural conditions new blanks in our knowledge become apparent. What may be regarded as some of the rougher work has been done. We must turn at least part of our attention to some of the finer aspects and investigate some of the borderline conditions which may mark the difference between a moderate degree of efficiency and high state of perfection in our swine nutrition.

I mentioned early in my talk that there are several parties who have an interest in swine nutrition. The farmer has a major interest because his success depends upon efficiency of production. The animal nutritionist must ferret out the problems which require solution and if possible foresee trends in production methods which may create new problems. He has a major responsibility in the field of swine nutrition. In view of the relationship between nutritional factors and the development of "deficiency diseases" and the bearing of diet on susceptibility to disease the veterinary scientist is drawn into the nutritional field. These two cannot be far apart in their research processes nor in their recommendations regarding nutrition and management procedures. In my opinion there must be the closest possible liaison between animal husbandmen and veterinarians. The feed manufacturer fills an important place in swine nutrition since he assembles feeds, blends them, and delivers to the swine feeder the ration or an important part of the ration which is placed before the pig. He can be and has been a great power for good in leading to improvement in swine nutrition. The blending and mixing of good feeds, in proportions suggested by careful experimentation, and their sale at fair price, makes an important contribution to the welfare of the swine industry. In extension work concerned with bringing science to the swine enterprise the feed manufacturer has done a notable job.

I close with a plea for the close co-operation of all concerned in the field of swine nutrition - the producer, the scientist, and the manufacturer. A spirit of good will, based upon mutual confidence, must prevail if the greatest contribution is to be made in maintaining a stable and prosperous swine industry in Canada.

by R. D. SINCLAIR. First published 1947, Canadian Journal of Comparative Medicine

This article hasn't been commented yet.