Effect of Phosphorus Deficient Rations on Blood Composition in Cattle.

Abstract

The authors 1 have described elsewhere a condition in which numerous cattle in Minnesota suffer from a mineral deficiency which causes stunting, osteophogia, general pica, delayed oestrous and other serious metabolic disturbance. The animals are fed largely on prairie grass pasture or hay, depending on the season, with a limited amount of grain. An outstanding characteristic of the hay is its relatively low phosphorus content, which often falls below 0.2 per cent P₂O₅. This fact points to insufficient phosphorus as the primary cause of the more or less disastrous results encountered. The further fact that bone meal or other forms of phosphate prevent and relieve the situation, when fed as a part of the ration, furnishes additional support for the phosphorus deficiency etiology of the disease.

We have recently obtained striking proof of these facts through a study of the inorganic Ca and P in the blood. The principal data secured to date are given in the accompanying table. All the animals had been reared in the P-deficient region and had been under experimental observation for at least 75 days when the first analyses were made. The hay fed during the period covered by the analyses as well as some months previous, was grown on mineral soil, low in phosphorus. The hay was of high quality for prairie hay; it had a bright green color and was palatable. The animals received all they would eat. The oats fed were of unknown origin, and were fed at the rate of 2 to 12 pounds daily, per head, depending on whether the cattle were dry or milking, and the milk production.