AbstractA total of 28 female goats were divided into 4 groups on the day of kidding and were treated with 0, 1.0, 2.0 or 3.0 mg/kg/day potassium cyanide (KCN) twice daily for 3 months. Whole blood cyanide, thiocyanate, plasma thyroxine (T4) and triiodothyronine (T3) levels were measured, and one doe from each group and all the males from every litter were euthanized for histopathological analyses. It was shown that no clinical signs of toxicity were observed in any goats from any group. However, 1 goat which received 3 mg/kg/day KCN died on the 55th day of lactation. Dam body weights were not affected by KCN doses but by lactation period. Both serum thiocyanate and cyanide levels were increased in all dams. In the kids, thiocyanate levels increased at all evaluated periods and peaked at day 30. Cyanide concentrations in the kids was highest at 30 days, followed by 60 days and were undetectable at 90 days posttreatment. T3 and T4 levels were unaffected by cyanide treatment. Histological changes included increased numbers of reabsorption vacuoles on the colloid of thyroid follicles and mild hepatocellular vacuolation and degeneration in both dams and kids in the experimental groups. In conclusion, kids that suckle from dams exposed to cyanogenic plants can be affected, as thiocyanate and possibly cyanide can be transferred from the maternal bloodstream to the kids via the milk, thus indirectly intoxicating the offspring.