WASTAGE IN HERDS

Taranaki Daily News, 4 January 1935, Page 12

WASTAGE IN HERDS

RAVAGES OF DISEASE. VALUE OF SOUND FEEDING.

Wastage in the dairy herds is due mainly to disease, including sterility. How far may diseases be reduced by an improvement in feeding? Recent work has shown that the nutrition of an animal, as determined by the nature of its diet, is an important factor in determining its resistance to disease. Many pathological conditions are due entirely to the lack of certain substances in the ration, and there is now evidence to show that in animals suffering from malnutritiori, the susceptibility, to at least some diseases, is increased, says an English writer. Animals most affected by deficiencies of essential nutrients in their food are growing animals, and pregnant or nursing females producing from their reserves the nutrients required for the growth of their young. One would expect that the cow would be especially liable to suffer from the effect of a deficient ration on account of the fact that the modern animal is producing “unnaturally’’ high yields under artificial conditions of housing and management. Further, she is usually both nourishing a calf “in utero,” and suffering the strain of milk production at the same time.

AMERICAN' EXPERIMENTS. In America experiments on rations abnormally low in lime showed that deficiency of lime in the food was followed by the birth of dead or weak calves, and sterility. Other work, in which rations were exceptionally rich in calcium, but very poor in phosphorus, showed that the animals suffered from decreased milk yield and bone weakness. In an experiment carried out in Britain at the Duthie Experimental Farm some years ago, it was found that, in a group fed on a ration poor in both minerals and vitamins, the wastage from disease was much greater than in a comparable group fed on a well-balanced, adequate ration.

It is only under experimental conditions and in certain areas that the ration may be so deficient in one special nutrient that a deficiency disease due to lack of that nutrient occurs; but a partial deficiency of several nutrients may be the cause of such common signs of unthriftiness as decreased appetite, lowered vitality, dull coats, subnormal growth and production, and it is possible that it may predispose to some infectious diseases. At the Duthie Farm, where the balancing of the ration for the maintenance of health is the main objective, the amount of disease has been abnormally low. Thus in a herd of fifty milking cows there has been no case of disease or ill-health of any kind in the past year. Observations on dairy cows are of little value unless they are extended over the whole lifetime of the animal, and one must speak with caution in view of the fact that our information is limited. It has been proved, however, that green food contains all the nutrients essential for health in the best possible form, and our limited observations, as far as they go, indicate the' value of feeding green food through the winter in the form of green forage crops and perhaps dried grass, together with as much sunshine and exercise as possible. Minerals are assimilated much more easily in the form in which they are present in foodstuffs, and it is often possible to balance a mixture which will contain a sufficiency of these nutrients without resource to inorganic supplements, e.g., by using good hay as a source of calcium, or bran as a source of phosphorus. For this reason the manuring and selection of crops which will increase the mineral content of the foods grown on the farm is of the greatest importance.

Fortunately most reputable firms putting dairy cakes on the market have taken advantage of the results of research, and are balancing up the concentrates used to make good deficiencies. Even if the ration be perfect with regard to its mineral and vitamin content, there still remains for consideration other qualitative aspects, such is the quantity and quality of the protein, the amount and kind of fibre, palatability and digestibility, and even on this aspect of the question our knowledge is very scanty. The necessity for feeding an adequate ration during the dry period is of the greatest importance. If the cow cannot rebuild her reserves after the strain of lactation and pregnancy, she is almost bound to be more susceptible to disease and infections.