Ration and the Dairy Cow

Sun (Auckland), Volume III, Issue 750, 24 August 1929, Page 31

Ration and the Dairy Cow

Relation to Production THE supply of protein is one of the most important problems demanding the attention in the feeding of farm animals— especially dairy cattle. The minute” cells iu animal tissue in which life is inherent are subject to continual wear and tear, which involves partial destruction of the protein they contain.

Normally, an animal to be kept in Store condition simply requires sufficient protein in its feed to restore this waste. Knergy must Also be supplied for the vital functions of the body—to keep the blood circulating, and to maintain body temperatures. This energy is supplied by the carbohydrates in the food, principally starch, sugar, and fat. When an ani- : maJ is deprived of food, the reserves j of carbohydrates in the muscles and rhe liver are first of all used to provide the necessary energy for the maintenance of life. The principal reserve tissue in the animal body is fat, and this is next drawn upon, yielding about two and a-hal£ times a 3 much energy as starch or sugar. At the same time, body protein is also used up to repair worn-out tissues in vital organs. But as long as the fat reserve lasts, the amount of protein drawn upon is small. When fat reserves are exhausted, protein is drawn upon for heat and energy production, and at this stage there is an abrupt rise in tho amount of nitrogenous matter contained in the urine. This generally marks the beginning of the end. as protein is but of equal value to starch as a heat producer, aud tv hen body protein is used for energy as well as for repairing broken-down tissue in vital organs, the available supply is quickly exhausted, and death foliowa after a period of rapid emaciation. It is obvious, therefore, that the process of life involves a continual destruction of body protein in the animal, hence tho animal must receive tor vital purposes only at least an amount of protein in its daily food sufficient to make good these losses. Scientific feeding standards are based upon the principle of supplying first of all an allowance of food containing sufficient protein and starch equivalent for maintenance, and then adding to this an allowance sufficient to meet other demands, such as the increased wastage of muscular tissue, and high

energy production necessary for a working horse, the addition of flesh in the case of rapidly growing animals, and the excess quantities of protein, sugar, and fat required for milk production, A store bullock weighing I,ooolb requires 0.71 b of digestible protein and 61b of starch equivalent for maintenance alone. Upon such a ration the animal would remain in a healthy j condition without losing or gaining ' flesh. In the case of the dairy cow I of I,ooolb live weight, an additional 0.61 b of digestible protein will be required for every gallon of milk produced. It must also be apparent that a young, growing animal requires more protein than a mature animal is accumulating mostly fat. If the ration contains an excess of protein, it functions iu much the same way as a carbohydrate, and can be used either for the production of energy or for fat production. The fattening value of lucerne pasture, for instance, is well known, but since lucerne contains an excess of protein, it is not economical to use it alone. The expensive outlay for concentrates upon dairy farms where cows of high producing capacity are kept, is mainly for the supply of protein, which is contained in fairly high proportion in bran, oil cakes, linseed meal, etc. Therefore it is not economical to feed an excessive quantity of protein. Indeed, an excess of protein may actually be injurious by throwing a heavy burden upon the kidnej-s, whose function it is to eliminate the large amounts of urea which arise in the body from such feeding. Th condition of “pulpy kidney's” sometimes found in sheep, and the skin affections sometimes found upon pigs and cattle grazing exclusively upon lucerne, are frequently attributed to the excess of protein obtained from this food. Some astonishing revelations with regard to the cost of production have been made upon dairy farms where animals of heavy' milking capacity are liberally fed yvith the concentrates

necessary to maintain the yield. It has been stated that those who practise the purchase of expensive concentrates simply cash their milk or cream cheque and take the money, or most o£ it, across the street to feed the dealer. It is certainly true that if purchasing all of the concentrates required to make up the necessary protein ration when, maize silage, wheaten or oaten chaff, or other bulky roughage of comparatively low nitrogenous content is used, the profits from the dairy herd are greatly diminished. On the other hand, if economy in the use of concentrates be practised, the production of milk will be seriously reduced. It is always a difficult matter to restore production once it has been allowed to decline. It must also be considered that heavy milkers, if not allowed ample supplies of protein in their feed, will lose condition rapidly, as there will be a serious drain upon the muscular tissues of the body to provide the requisite protein for milk production. The problem ot protein supply is less acute during | the spring months, when there is j ! ample green pasture, because a good j i mixed pasture provides almost, a bal- j | anced ration for stock. Since most ! j dairymen so control their herds that | the cows will freshen fn the spring, j i the greatest possible use is made of I the natural pasture. Still the fact re- 1 mains that dairymen would greatly in- ; crease their profits if they were able j to maintain a higher milk flow during the autumn months, and even, to carry a large number of cows right through tho winter. This could be done ecocomically only by growing a larger proportion of nutritious fodders upon the farm. Few farmers produce as much good clover or lucerne hay as they could profitably use. More use could be made of clovers in all dairying districts. The perennial red clover would probably be found the most valuable in districts suitable to its growth. It produces abundance of leafy steins, and makes very palatable and nutritious bay. But in any district a mixture of pease and oats grown and cut for hay at the proper time is capable of producing a quality of roughage that can compete closely with lucerne or clover. This crop has been grown largely upon many experimental institutions where not only has its efficacy as a nutritious fodder been proved, but its cost of production expressed in terms either of 1001 b. of dry | matter or in the cost of producing j 1001 b. of milk, has compared very fav- | ourably with all other classes of fodi der crops. This crop also makes ex* | c.elleut silage, and thus may be used i for maintaining a supply of highly mi- | tritious, succulent feed during a dry j autumn or a winter when green feed In the United States an interesting experiment has been carried out in the use of sea plants for dairy cows. Ivelp, an aquatic crop, and iish living i in the Bea have in them the mineral i matter necessary to optimum nutrition, says G. Jenny in the “Now Breeders’ Gazette,” Chicago. When these foodstuffs are dried and ground and fed, the elements lost from the soils by the leaching rains of centuries and now concentrated in the sea are returned to our farm animals, and through their meat, milk, or eggs to man himself. By feeding the milk cow certain proportions of kelp and ground dried fish —tunney fish minus the white meat —in her rations, we can, supply the natural amounts of the essential minerals her feed lacks, and at the same time provide animal proteins of the best quality to the ration. By feeding kelp we can restore those minerals which she cannot help draining from her own system every day to maintain her milk production. The owner of the Rock River arms in July, 1328, submitted part of her choice herd of Friesians to test. Powdered kelp and ground fish meal in commercial mixture were fed to all the cows in milk in the proportion of one part of mixture to 10 parts of grain. The test was to determine whether or not the sea products, rich in iodine, might impart to the milk so produced enough “organic” iodine to render the milk valuable as a preventive of goitre or a relief agent in case of incipient goitre. At the beginning of the trial it was ascertained first that the milk from ordinary grain and roughage rations contained no iodine. The cows took readily to the kelp and ground fish meal from the first, and after three weeks of feeding, Mr. George W. Cavanaugh, head of the department of chemistry at Cornell University, tested the milk and found it to contain iodine. To be effective in preventing goitre milk must show at least 150 to 200 parts of iodine to a billion parts of milk. After six weeks of further addition of the kelp-fishmeal products to the ration another test was - made. If was found that the iodine content in the milk exceeded ”00 parts to the billion, demonstrating conclusively that milk could be iodised.