SECTIONAL TRANSACTIONS.—M. 51 
Or 
ScIENCE AND ANIMAL HEALTH :— 
Sir Arnotp TuerLter, K.C.M.G.—The Pathological Aspect of Mineral 
Deficiency in Cattle. 
At the Oxford Meeting, August 1926, a paper was presented by Dr. P. J. du Toit 
dealing with experiments on ‘Minimum Mineral Requirement in cattle’ carried out 
in Onderste Poort by Theiler, Green and du Toit. Striking results had been obtained 
by feeding young heifers with food deficient in phosphorus but adequate in calcium. 
A disease was produced resembling in all respects that known locally under the name 
of Stiffsickness, occurring in cattle on pasture poor in phosphates. On the other 
hand, heifers that had been fed on food poor in calcium but adequate in phosphorus 
did not show any clinical changes at all. It was concluded that for growth, the 
requirements in the case of phosphorus are higher than in the case of calcium. Some 
of the heifers used in these experiments were subsequently killed and the bones were 
collected for histological examination. The disease, Stiffsickness, was tentatively 
identified with that known in the European veterinary literature as Osteomalacia, 
but no proof could be given for the identity of the two. The present paper deals with 
the identification of the osseous lesions found in Stifisickness by comparing them 
with those found in Rickets and Osteomalacia as described in men and higher animals. 
These two terms are used in pathology to signify identical changes: Rickets for the 
disease in adolescents and Osteomalacia in adults. From a pathological-anatomical 
point of view they include definite and typical lesions of the skeleton by which the 
disease can be identified, viz., a suwperabundance of osteoid tissue, which, when profusely 
produced in the epiphyseal lines of adolescents, interferes with the longitudinal growth 
of the bones, and gives rise to symptoms that are generally described as Rickets. The 
result of the investigation was, that in all cases where phosphorus was deficient, a 
marked degree of atrophy of the bony tissue was found, generally known as Osteo- 
porosis, accompanied with a marked increase of osteoid tissue, corresponding more or 
less in amount with the degree of phosphorus deficiency in the food. The disease 
Stiffsickness can, therefore, be definitely identified with true Rickets and Osteomalacia. 
In the case of the heifers fed with calcium deficient food, the changes in the bones 
were but slight and amounted to a very moderate Osteoporosis, but there were nowhere 
indications of an increased osteoid formation. The atrophy in the bones of the 
phosphorus deficient heifers was very marked and more pronounced than that in 
human Rickets. Whilst Osteoporosis apparently does not always belong to the 
anatomical changes of Rickets in men, it was constant in our heifers. It has to be 
considered as a primary change in Rickets of growing cattle. It precedes the formation 
of osteoid tissue, which appears to be a secondary formation to compensate the loss 
of the bony tissue which becomes absorbed, the phosphorus being required elsewhere. 
Since the supply of phosphorus in the food is insufficient, the newly-formed osseous 
tissue mustremainosteoid. Inthecase of calcium deficiency the atrophy was not so far 
advanced as to necessitate a compensation of the tissue removed, hence no osteoid. 
The fact that insufficiency of calcium in the food produced but a slight osteoporosis 
and did not give rise to clinical symptoms during life, has to be emphasised. It is, 
therefore, not justifiable to speak of Rickets and Osteomalacia in cattle as being caused 
by deficiency of lime, although theoretically such a possibility must be admitted. 
Accordingly, Rickets and Osteomalacia in pasture cattle are exclusively caused by 
extreme deficiency of phosphorus. The lack of activated ergosterol or vitamin D 
played no réle in the causation of the disease in our cattle, since the heifers had been 
exposed all day long to the influence of the sun. The absence of light seems to be a 
factor necessary in the causation of artificial Rickets in rats and in that of children 
observed under natural conditions. It is evident that it is not in Rickets of pasture 
cattle. Rickets and Osteomalacia in pasture cattle must be considered as advanced 
stages of a true Aphosphorosis, by which term we understand a definite syndrome, 
typical of phosphorus deficiency : Osteophagia, Osteoporosis, Rickets (in young) and 
Osteomalacia (in adult animals). 
Dr. J. B. Buxton.—Tuberculosis. 
LL2 
