Vitamin A Deficiency in Cattle: Prevention and Welfare

Understanding vitamin A deficiency in cattle — a preventable nutritional condition with significant welfare impacts.

Key Facts

Vitamin A deficiency occurs when cattle consume hay or straw diets for extended periods without supplementation
Beta-carotene in fresh grass is the primary source — stored feeds lose carotene rapidly
Signs include night blindness, reproductive failure, compromised immunity, and neurological disease
Calves born to deficient cows are weak, have poor immunity, and are highly susceptible to infection
Prevention through supplementation or access to good-quality pasture is straightforward

Welfare Considerations

Vitamin A deficiency causes welfare impairment across multiple body systems. Night blindness — the earliest sign — means affected cattle cannot navigate their environment in low light, causing accidents, disorientation, and injury. Immune function is severely impaired, making deficient cattle susceptible to respiratory, enteric, and systemic infections that they would otherwise resist.

Reproductive welfare impacts are significant. Vitamin A-deficient cows experience conception failure, embryonic death, abortion, and birth of dead or weak calves. The welfare cost of each lost pregnancy — and the suffering of a deficient cow — represents preventable harm from a nutritional oversight.

Calves born to deficient cows face compounded welfare problems. Born with inadequate immune reserves, they are highly susceptible to neonatal infections. Their colostrum is vitamin A-deficient, failing to provide the passive immunity that newborn calves depend on. Simple supplementation of pregnant cows prevents this cascade of welfare failures.

What You Can Do

Supplement housed cattle on hay or straw diets with vitamin A during winter housing periods
Provide high-quality hay or access to fresh pasture to maintain adequate beta-carotene intake
Give vitamin A injectable supplementation to breeding cows 2-4 weeks before calving if diet is poor
Monitor cattle for early signs of vitamin A deficiency: night blindness, poor hair coat, eye discharge
Ensure calves receive adequate colostrum from well-nourished cows for immune protection