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AN OVERVIEW OF VITAMINS AND MINERALS FOR GOATS
By: Unknown Author |
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Introduction
Minerals and Trace Elements Goats have an ability to thrive in the harshest environments. Their high digestive ability enables them to deal with high cellulose/high fibre diets of a very coarse nature. Anatomically goats are similar to other ruminants but with respect to mineral and vitamin requirements until recently, very little research had been carried out. That which has occurred has been performed almost by accident using goats as an inexpensive substitute for the cow. There is very little substantial data and very few definitive text books, which is very odd when one considers that there are over 400 million goats worldwide and more goats than sheep in the EU. In fact in some places e.g. The Sudan there are four goats for every person. Recent surveys show that there are many areas deficient in certain minerals. However, the goat is an intelligent animal and usually manages on free range to eat herbs, weeds and other deep rooted plant material which has relatively high mineral content. However, real free range is very rare in the U.K. and for that matter this is true over a large proportion of the world. If a goat of say 40-45kg (88-99 lbs) bodyweight gives 4.5kg (1 gallon or 1.2 US gals)of milk per day that is equal to a cow of 500kg (1100 lbs) giving 50kg (11+ gallons or over 13 US gallons!) No such animal exists. A goat is at least 50% more productive and efficient for its bodyweight than a cow. This means that if a goat is giving its own bodyweight in milk every 10 days or less, it is therefore utilising vast quantities of vitamins and minerals. At its extreme, top goats in the UK have been known to yield consistently 9kg (nearly 20 lbs) of milk per day, which is equivalent to her own bodyweight every 5 days! A goat also needs more minerals and vitamins for maintenance too: with its relatively large digestive system in relation to its body size, the work of digestion involves the use, and loss, of large quantities of minerals. Before we take the minerals and trace elements individually, there is no absolute distinction between the two - it is merely a matter of degree. Elements that are used at high levels are referred to as minerals, whereas low levels are called trace elements.
Calcium (Ca) and Phosphorous (P) The skeleton is the store for both Ca and P and somewhat surprisingly, the goat can add and draw from this reserve in times of deficiency. There is normally a positive calcium balance during pregnancy when the skeleton is added to and a negative balance after kidding where up to 30% of the skeleton may be utilised. A goat requires 1.3g of Ca and 1.0g P for each 1kg of milk produced: it requires 7.lg Ca and 4.9g P daily for maintenance. If we consider both these figures it is obvious that a Ca:P ratio of 1.4:1 is ideal, suiting both the above. Calcium deficiency manifests itself by rickets, milk fever (especially after kidding). Lack of Vitamin D will also help promote this, since it is required for retention of Ca in the bones. Phosphorous deficiency is more likely, less severe and harder to diagnose. Basically it causes 'poor thrift,' lower milk yields and general lethargy. Ca and P work on the thyroid gland together with Iodine to govern the metabolic rate - i.e. yield appetite, 'rate-of-living'. Very crudely, Ca acts as a brake and P an accelerator. Unlike cows, goats excrete a large proportion of Ca and P and therefore have a relatively large requirement.
Magnesium (Mg)
Zinc (Zn) Zinc has a profound effect on males - much more than females - since it is involved in sperm production and the development of the sex organs. Deficiency symptoms include high bacteria in the mouth with excess saliva, stiffness of the joints and a low male sex drive. In vegetable diets Zn combines with phytic acid to form insoluble salts and becomes unavailable. Dry diets are more likely to cause parakeratosis and wetting of the feed hydrolyses the phytate salts and liberates the Zn. - so wetting of the feed for males is recommended. Zn deficiency is best spotted by the condition of the coat - there is reduced hair growth, a staring coat and also lameness. Zinc is not very toxic, one would need around 1000 p.p.m. to cause problems. However vast overfeeding or grazing in close proximity to smelting works has given rise to reports of excess, which interferes with iron and copper uptake, in turn giving anaemia. Zn in milk is proportional to feed intake and since goats milk is usually too low in zinc to be ideal for human requirements, supplementing with Zn is a real benefit, especially when the milk is required for feeding to babies.
Manganese (Mn)
Iodine (I) Iodine concentrates in the thyroid gland in the throat and is used in the production of thyroxine - thyroxine sets the pace for the goat's metabolism. Only 0.15mg per day is required but this is essential. The percentage of Iodine available is proportional to its concentration in the soil and not what is growing on it, i.e. the same Iodine percentage occurs in grass as in deep rooted weeds. It is worth noting that Iodine should be fed with care as excess will easily put a goat off its feed. The main deficiency symptom is goitre whereby the thyroid swells in an attempt to work more efficiently with what little Iodine is available. A harsh coat is also common and perhaps the birth of live males, but dead female kids. The female has a larger thyroid gland and a bigger need for thyroxine and therefore a greater need for Iodine.
Copper (Cu) Again deficiencies are very noticeable in the coat with 'spectacles' forming around the eyes, especially noticeable with dark haired goats. More serious Cu deficiencies can be seen with the appearance of 'Swayback' where the back actually does sway and the goat has difficulty walking. In the UK the most well-known Swayback area is in Derbyshire and there are also 'Teart' areas where goats suffer Copper deficiency caused by the presence of excess Molybdenum in the soil which prevents the copper being absorbed. Cadmium also has the same 'blocking' effect as Molybdenum and this has occured when goatkeepers have put contaminated waste sludge on to their pastures to act as a fertiliser.
Selenium Basic feedstuffs are often deficient in Se and many have selenium rich compounds added to compensate. Strangely, weeds and deep-rooted plants have a greater concentration of minerals than grass, yet for Se it is the same for all growth. Therefore the best guarantee for adequate Se is to 'Selenise' the soil via a special Se rich top-dressing.
Iron (Fe) For adults a daily intake of 75mg is considered acceptable for lactating goats. Deficiency is relatively rare in farm animals with anaemia being the standard symptom. The diagnosis is not straightforward however since it is usually associated with other mineral imbalance problems. Iron toxicity is very rare because of huge doses needed to cause problems. The Fe in grass and oil meals (100-300mg per kg), in Dicalcium phosphates or limestone (500mg per kg) and cereal grains (30-60mg per kg) should provide enough. Any extra poses no problems and the Fe content of the milk is NOT dependent upon the diet (very different from Iodine).
Cobalt (Co) For the relationship between Co and Vitamin B12, see the appropriate Vitamin paragraph below.
Sodium (Na) It has been reported by McKenzie that all feral goats in the UK live near the sea because salt is so important to their existence. This is clearly nonsense since wild goats also exist in the centre of Asia 3000 miles from the sea!
Potassium (K) Vitamins
Vitamin A Carotene is converted in the intestinal wall and this depends upon the thyroid gland. Since the thyroid is very large in the goat, this animal is a very efficient converter of Vit. A - in fact all carotene is converted: this is why goats milk is pure white whereas the milk from cows (relatively inefficient converters) is still yellow with uncoverted carotene present. Deficiency symptoms are rare and include night blindness, poor reproductive performance and metritis. Vitamin A is destroyed by sunlight and therefore old hay is very low in this vitamin. In winter make sure that kale and other feedstuffs high in Vit. A are fed. For the new-born kid the colostrum is very important since they have very small reserves of Vit. A. It is worth noting that the Vitamin A content of goats milk is directly proportional to the amount of beta-carotene occuring in the feed.
Vitamin D Deficiency symptoms are uncommon but goats that are kept indoors in winter etc. are most likely to suffer and therefore need supplementary feeding. Deficiency of Vit. D is a major cause of rickets, bow legs and osteomalacia and whilst it cannot make up for any absolute deficiency in Ca and P, Vit. D will compensate to some extent to help overcome any imbalance between the two. As in cows, there is a high output of Ca & P into the milk and Vit. D is needed to maintain mobility of these minerals. It has been suggested in France that extra Vit. D is given in the last weeks of pregnancy to prevent hypocalcaemia (milk fever) and this does seem to be very sensible.
Vitamin E Vit. E is found in oil meals and bran - however, if goats can be persuaded to eat cod liver oil, recent evidence shows that deficiency symptoms are CREATED by forming gut conditions favourable to the destruction of both Vit. E and Selenium. The method of storage of feedstuffs is very important as the concentration of Vit. E is dependent upon it: basic feedstuffs can easily be made to be very deficient simply by bad storage conditions. Goats transfer Vit. E into the milk more readily than cows and should therefore receive daily adequate supplies of this vitamin to ensure milk quality. Apart from white muscle disease and muscular dystrophy, lack of Vit. E also causes sterility in males. Note that kids have no reserves of fat soluble vitamins (A,D & E) and sudden death of kids less than 2 weeks old is often due to lack of Vit. E in particular. This is normally overcome by feeding colostrum but the Vit. E content is also affected by the nutrition of the dam during pregnancy. With kids there is degeneration of muscle including the heart, whereas in older animals it will manifest itself as stiffness of the limbs.
The B Vitamins 1. inhibition of synthesis of certain B Vitamins by substances in feedstuffs occurs, especially those with high starch levels. 2. parasites in the gut totally remove certain B vitamins. 3. some B vitamins cannot be synthesised in sufficient quantities to meet demand - especially with heavy milkers and the shortfall must be provided via the feed.
Vitamin B1 (Thiamin) There is a relationship between Vit B1 deficiency and disease resistance and deficiency causes damage to the central nervous system (polioencephalomacia and cerebrocorticalnecrosis - PEM and CCN). This is exhibited by collapse, twitching etc. and the only cure is Vit B1 injection. 50-60mg per day is the recommended daily intake. Vit. B1 is also used as a preventative for acetonaemia. Nicotinamide. Also a member of the B group vitamins. Recent evidence again shows limited synthesis and the majority of the vitamin is derived from the goat's feed intake. Supplementation improves milk production and butterfat levels. There is good evidence that Nicotinamide present in cereals is 'bound' i.e. not available and therefore must be added by supplementation in the diet.
Pantothenic acid It is found in fresh vegetables and, in milk, bound to the proteins. It serves an important function in the formation of enzymes and certain antibodies, and since recent evidence has shown that deficiency can occur, it is always best to incorporate it in the feed via supplementation on a daily basis.
Vitamin B12 (Cyanocobalamin) Obviously, administering even more Cobalt is NOT the answer as this creates further problems and the best solution is to ensure a low daily dose of Cobalt is provided and in the case of B12 deficiency, an injection of this vitamin, whilst the gut flora returns to a normal healthy state. Much more research is needed in this vital science - very little data is available to goatkeepers with respect to Vitamin C, Vitamin K, Biotin, Folic Acid as well as other trace elements such as Fluorine, Chromium etc. - and what about amino acids, enzymes, fatty acids etc.? Only time and continued research will enable us to understand more fully the requirements of the goat and thus be able to cater adequately for her needs. |
About the author: No author information was cited for this article. However, the article can be viewed in its original format at: Vitamin and Mineral Requirements for Goats |
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