Thyroid histological changes in lambs from iodine-supplemented and untreated ewes

Abstract

Aim. To identify the histological changes in the thyroid associated with subclinical goitre.

Method. Thyroids were histologically examined from lambs that died within 24 hours of birth in a trial to investigate the effect of iodine supplementation to Merino ewes on perinatal mortality.

Results. Thyroids with follicles depleted of colloid, infolded and lined by columnar epithelium are indicative of hypothyroidism. These findings can occur in thyroids considered to be in the normal weight range of less than 1.3 g.

Conclusion. Thyroid histological changes are a useful aid in diagnosing subclinical goitre.

Key words:

• Sheep
• subclinical goitre
• thyroid histology