Vitamin A and E for sheep and cattle

Vitamin A is an important nutrient for cattle and sheep.

Vitamin A itself does not occur in plants, but the substance carotene in green plant material is converted by animals with an enzyme in the wall of their intestine to vitamin A. Carotene gives plants their yellowish colour and it is converted into active vitamin A.

Cattle uses 8 parts of carotene to develop 1 part vitamin A whereas sheep only need 6 parts of carotene to develop one part of vitamin A.

  In general, green pasture, hay with good green colour and yellow maize all contain sufficient carotene to allow the animal to produce enough vitamin A to top up the reserves stored in the liver.

 During winter we find a decline in carotene levels in plants with subsequent vitamin A deficiency problems in animals in late winter and spring. Vitamin A requirements increase during growth and pregnancy. It is one of the most important vitamins in the body because it is important for normal: growth, reproduction, sight and protective mucous membranes. 

Rams that are to be used for breeding ant that have not had access to any green feed for 2 – 6 months should be given vitamin A minimum of 6 – 8 weeks before mating.  

Vitamin E  

The adage that "the ewes are walking away from the lambs" may well be heard for the wrong

reason. If your ewes have not had green feed for three or four months, then lambs may be lacking vitamin E.

 Vitamin E, unlike vitamin A, is not stored in the animal body in large amounts for a length of time and consequently a regular dietary source is important. 

Green fodders are good sources of Vit E. Cereal grains are also good sources. Animal products are relatively poor sources. 

Vitamin E plays an important role in the development and function of the immune system. The most frequent form of vitamin E deficiency in farm animals is muscle degeneration. A popular descriptive name for this condition is “white muscle disease”, owing to the presence of pale patches or white streaks in the muscles. The condition is frequently referred to as “stiff lamb disease”. 

 Sheep grazing on green pasture build up some reserves in the liver. Vitamin A prevents “night blindness”. It has a particular importance in growth, reproduction and the immune system. Vitamin A is important in the resistance to disease and promotion of healing through its effect on the immune system. In breeding sheep a deficiency may lead to infertility and in pregnant animals to abortion, short gestation, retained placenta or to the production of dead, weak or blind lambs. Deficiencies will occur if the sheep have not any green forage available for a prolonged period. 

Excellent management is to give Vit A and E supplements to ewes a month before lambing and a month before mating.