This usually coincides with the last third of pregnancy when the requirement for vitamin A is greatest. Vitamin A deficiency may result if moldy or spoiled forages are fed for long periods. A deficiency include reproductive problems in both males and females. Pregnant cows may abort, retain their placenta and develop uterine infection, or give birth to weak, dead or blind calves. A deficiency produce semen with low numbers of sperm and more abnormalities than expected.
Diagnosis is made by analysis of blood samples or a post mortem examination.
In Alberta, the occurrence of this problem varies from year to year depending on forage quality. Allergy Badly molded feeds often contain large numbers of fungal spores. Cattle that inhale these spores may develop a respiratory allergy or bovine interstitial pneumonia. This disease prevents adequate amounts of oxygen from reaching the blood stream. An infected cow will gasp for breath and the developing fetus may die due to oxygen deprivation.