Toxic effects of subabul (Leucaena leucocephala) on the thyroid and reproduction of female goats

Abstract

Subabul (Leucaena Leucocephala) leaves although highly palatable and rich in protein has a limitation as a fodder due to the toxic mimosine content, which generally causes hypothyroidism and alopecia in animals. Studies on the reproductive performance of female goats were carried out by feeding green subabulleaves as a sole feed or at 50% level of roughage or 100% crude protein requirements over a period of 4 weeks to 14 months. The studies showed that out of 35.5% of pregnant goats, 44.5% aborted at different stages of gestation. Feeding of 50% subabul roughage for 3 to 8 months showed that 3 out of 5 (60%) animals had conceived and 1 animal aborted, while at 100% crude protein levels, the conception rate was 80% and no abortions took place indicating that the reproductive failures and abortions were proportional to the daily ingestion of subabulleaves and mimosine. Thyroid glands of all the experimental groups were enlarged weighing 1.78 to 5.75g and exhibited colloidal and hyperplastic goitrogenic changes. Thyroid glands of the aborted fetus and the kids born to the subabul fed animals were also enlarged weighing 0.526 to 3.5g; showed parenchymatous and colloidal goiter indicating that subabul feeding not only caused hypothyroidism and reproductive failures in the female goats but also caused congenital goiter in the progeny. These finding suggested that subabul feeding would adversely affect the reproductive performance of the female animals and is hazardous.