Understanding how vitamins work in goats By Dr. Steve Hart
Many producers take vitamins to sup- port their health, but do goats need vitamins? Vitamins are often put into goat feeds and often into mineral supplements. Does your goat get their vitamins? Vitamins are divided into two classes — water soluble, which are the B vitamins and then the fat-soluble vitamins, which in- cludes vitamins A, D and E. Generally, the rumen synthesizes suffi- cient B vitamins to meet the goat’s needs with one exception, which will be discussed at length. B vitamins are not stored in the body and need to be supplied daily. The other vita- mins A, D, E and K, are fat soluble vitamins. Fat soluble vitamins are stored in the liver and are adequate for a couple of months. Vitamins are measured as International Units (IU), which means a certain physiolog- ical response by the animal. More recently, we can measure the level of certain chemi- cals and calculate international units from the level of chemicals. Vitamin K is synthesized by bacteria in the lower gut and absorbed there. It is also synthesized in plants where it is part of the photosynthesis process. Vitamin K is impor- tant in blood coagulation and bone calcifica- tion. It is called vitamin K for the German spelling of Koagulation. The rat poison Warfarin (or other trade- names) interferes with vitamin K in the blood coagulation process. That is why when ani- mals get into rat poison containing Warfarin or similar anticoagulant, the vet gives the ani- mal Vitamin K to counteract the poisoning. Vitamin K is produced in adequate amounts in the body so that we don’t worry about sup- plementing it. Vitamin A plays an important role in vi- sion, the immune system, bone formation, skin integrity and embryo development (re- production). The classic symptom of Vita- min A deficiency is night blindness. Deficient animals have watering of the eyes. Reproduction is depressed in both males and females.
Leafy green forage has high levels of
vitamin A. There is no need to be concerned about a Vitamin A deficiency when animals are grazing green forage. Vitamin A is pres- ent in green leafy hay but gradually declines during storage. Vitamin D is known as the sunshine vi- tamin because it is synthesized in the lower layers of the skin, epithelium, when the skin
November 2025 | Goat Rancher 9 Many mineral and feed mixes include vitamins.
is exposed to ultraviolet sun radiation. Vita- min D is important for absorption of calcium as well as magnesium and phosphate, all components of bone.
As one would expect, the classic symp-
tom of a Vitamin D deficiency is bowed, crooked legs because there is not sufficient calcium to make the bones strong and rigid. Recently, vitamin D has been found to be im- portant in immune system functioning. Vitamin D is adequate in animals ex- posed to the sun for a couple of hours a day. There are some liver stores of Vitamin D that supply the vitamin when the animals are not exposed to the sun for a while. Vitamin D de- ficiency was first diagnosed in dairy calves
being raised in the basement of dairy barns because they had no access to sunlight. Vitamin E is an important anti- oxidant that works in conjunction with the trace mineral Selenium in maintaining the integrity of cell membranes. It is also important for reproduction, as the major defi- ciency symptom is poor reproduc- tion. Vitamin E is also known as tocopherol, from Greek words mean-
ing birth or to bear. A deficiency can also cause nutritional muscle dystrophy (stiff lamb disease) and white muscle disease. Kids are too weak to nurse. The kid shakes with pain when in a standing positon and there are white streaks in skeletal muscles and heart muscle. Repro- duction problems include poor conception rates, abortions, stillbirths, miscarriages, re- tained placentas or delivery of weak kids. Vitamin E is present at more than adequate levels in green forage. However, hay loses 50% of its Vitamin E a month in storage, twice as fast as vitamin A. The newer feed standard (NRC 2007) Please see HART, Page 23
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