This mineral is required by the animal but it is not made in the animal. it plays a key role in immune response (function) and iodine metabolism. Grazing animals may be at more of a risk to deficiency.
Its main role in the body is as an antioxidant enzyme glutathione peroxidase. We can measure this in blood to help look at mineral status (long term) while plasma serum levels are used to measure short term intakes.
It has been linked to a disease called white muscle disease. With reduced growth rates and illthrift.it can also play an important role in poultry and pigs.
It may also play a role in fertility and in the production of healthy sperm in the male animal.
It has been linked to retained placentas in cows, however it is a minor contributor in these cases. It must however be factored in and ruled out after negative energy and low blood calcium.
This is a mineral where we must carefully match supply to needs. Oversupply can lead to toxicity with several side effects.
It can be closely linked to vitamin E also which plays a key role in immune function as an antioxidant. Deficiencies of both can look similar, so must be considered together.
Supplementation is set at a maximum level of 0.5mg/kg