Although not strictly relevant to the foregoing matter, a few remarks may here be made on the subject of goitre.
True goitre consists in hyperplasia of the follicles of the thyroid gland, with colloid change of their contents, which are chiefly albuminous. The swelling is mainly due to enlargement of the follicles, and is termed struma follicularis. It may attack the entire organ or only one-half; less frequently it is confined to certain sections. Other varieties of goitre are recognised, such as fibrous, varicose and cystic goitre. (For fuller details see Möller and Dollar’s “Regional Surgery,” p. 149.)
Fig. 213.—Calf showing swelling due to goitre.
Treatment by injection of thyroid juice or by feeding on thyroid extract has given better results than drugs.
The following account of an outbreak in New Zealand is summarised from the Annual Report of the Chief Veterinarian of New Zealand, 1901:—
The calves affected were born with enlarged thyroids. The farm is of rich alluvial deposit, and rather below the level of the river, which it borders. The land has been in occupation, however, for many years, and no similar condition had been previously noted. At first, as calves only were affected, it was thought possibly to be due to the bull, a two-year-old animal, but when a foal was born suffering from a similar malformation this theory naturally fell to the ground.
The land had been ploughed with a special plough 20 inches deep, but this is no uncommon practice in the island.
About the same time, a similar disease was discovered affecting lambs at a farm near Outram. From 450 ewes, 150 lambs had been lost, the glands being enlarged to the size of a cricket ball. A few had been born dead, many only lived a few hours, others lived several days, and a considerable number recovered. There was no connection, directly or indirectly, between the two farms, they being at least fifty miles apart. A few of the calves died or were killed, the remainder recovered, and the foal grew rapidly better. The land on both farms is very similar in composition.
Mr. Wilkie states, from observation of previous cases in lambs, that “it appears to be always associated with malnutrition and a condition of anæmia in the parent, induced in most cases by feeding with watery, innutritious foods.”