The thyroid gland is responsible for controlling the metabolic rate of the body. A lack of iodine indirectly influences growth rate, milk production and feed consumption. Iodine deficient animals may have delayed puberty and frequently do not show signs of heat. Other deficiency symptoms include poor conception rates, abortions, longer gestation periods and the birth of dead, weak or hairless calves. Goiters develop when an iodine deficiency is severe.
High nitrate feeds reduce the uptake of iodine in the digestive tract.
Grazing on pastures containing many plants belonging to Brassica spp. Animals deficient in cobalt have a poor appetite, loose body condition and are weak. The conception rate of cows in an affected herd may decline. Low cobalt levels reduce the storage of copper in the liver and can interfere with the activity of manganese, zinc and iodine. Sodium and Chloride Sodium and chloride, the components of salt, are essential nutrients.