Massive goitre (Struma parenchymatosa) in geese

In a goose flock consisting of 2300 birds of 6 months of age severe goitre was diagnosed. To the best of our knowledge this is the first report of nat urally occurring goitre in geese, which is not related to the feeding of ra peseed meal. The major pathological findings included retarded growth and p lumage development, significantly (300%) increased relative thyroid weight, fat accumulation in the mesenteric and abdominal region, and lipid infiltr ation of liver and kidney cells. Subsequent hormone analysis showed undetec table thyroxine (T-4) levels and a dramatic drop in triiodothyronine (T-3) plasma levels of the diseased geese. Thyroidal histology displayed the typi cal signs of struma parenchymatosa. In order to get more information about the possible causes of the goitre, 10 geese from the affected farm were tra nsferred into the laboratories of the Central Veterinary Institute. The gee se were allotted into two groups. Group I received iodine supplementation f or 55 days, while the other group served as sick control (Group S). Iodine treatment caused a dramatic improvement in the birds' clinical condition ex cept in plumage growth in Group I, while the clinical and main pathological signs of goitre remained unchanged or worsened in the untreated Group S. C ontrary to this, the serum levels of thyroid hormones and responsiveness to thyrotropin releasing hormone (TRH) improved not only in Group I but also in Group S. Almost euthyroid biochemical parameters were found after 55 day s of iodine treatment in Group I and, surprisingly, a considerable improvem ent (especially in serum T-3 levels) occurred also in Group S. These findin gs confirm the diagnosis of goitre but also call attention to the fact that iodine deficiency was not the only factor eliciting the disorder. The unde rlying possible goitrogenic substance could not be traced down.