- Droughtfeeding of Angora Goats
|Last update: March 30, 2012 12:23:02 PM|
Droughtfeeding of Angora Goats
D. Wentzel, Grootfontein College of Agriculture, Middelburg, C.P.
DROUGHT is a natural and characteristic phenomenon of the extensive grazing regions of South Africa where Angora goats are mainly found. The concept of droughtfeeding normally refers to the varying degrees of supplementary feeding necessary to meet the animals' nutritional requirements during droughts. In order to achieve the most effective supplementary feeding practice it will always be necessary that the supply of nutrients by the natural feed sources on the one hand, as against the nutritional requirements of the animal on the other hand, be used as basis. It is obvious that various factors can effect the aforementioned and it is therefore desirable to discuss the most important ones.
Natural grazing which is the primary source of nutrients of Angora goats can vary markedly in the volume of edible matter which is produced under normal circumstances. Each farmer must therefore evaluate his natural pastures (also with regard to various camps) in order to guard against over utilisation during normal years. In addition, the grazing should also be evaluated with regards to the actual nutritional value and possible inadequacies which may exist.
The natural grazing is hardly ever in a static condition, but changes regularly either as a result of seasonal and long term climatic influences or due to the effects of the grazing animal.
In general, droughts usually cause a decrease in the production of edible matter as well as a decrease in the nutritional value of this material. The magnitude of these decreases will naturally increase according to the severity of the drought. In the traditional mohair producing areas this decrease in production and quality of the edible matter causes an energy deficit which is usually the limiting factor for mohair production under extensive conditions. Although a protein shortage may follow it is only usually at a stage when the availability of edible matter is so low that complete withdrawal of stock should be considered. According to available information it appears that there is no advantage in the additional feeding of any minerals in these regions. As regards Vitamins, a Vitamin A deficiency may occur during droughts, but considering the grazing habits of the goat and the fact that even during serious droughts green shrub material is still available, the necessity of such supplements is doubted.
In light of the above it is therefore clear that drought conditions usually result mainly in an energy deficiency and therefore the primary aim of feeding programmes must be to rectify this deficiency. It is however necessary to first look at the requirements of the animal.
From available information it appears that on a weight basis the nutritional requirements of Angora goats compares with those of sheep to a large extent. It is, however, generally accepted that the total average intake of dry material by Angora goats is appreciably lower than that of sheep, apparently because of differences in physical size. It therefore follows that the highly productive Angora goat will, of necessity, need a better quality ration because the animal cannot consume enough of a low quality ration in order to satisfy its nutritional requirements. In practice, especially during drought conditions, this aspect has the result that Angora goats often suffer from an energy deficiency with associated problems such as abortion, poor growth and hair production, low conception rates and so on. On the other hand it explains why good results are generally obtained when energy supplementation is practiced when the grazing is relatively poor.
However, all Angora goats do not have the same nutritional needs and those animals with a higher requirement will need a better quality ration. In other words those animals with higher requirements are the first to suffer when the quality and quantity of edible material in the grazing declines. Lactating ewes and kids have the highest nutritional requirement per unit of mass, followed by ewes in the late stages of pregnancy, young growing animals and lastly adult animals.
The veld versus the animal
In order to accomplish the most beneficial supplementation it is thus obvious that two aspects must be1aken into account, namely the specific animal's nutritional requirement and to what extent the source of nutrition can satisfy this requirement. The most effective and most economical supplementary feeding will then be to supplement actual deficiencies, if any.
Against the background of the complex and indefinable nature of our natural food source and the different requirements of various types of animals, it is impossible to lay down an absolutely correct supplemental programme, so that general guidelines can only be given.
As previously mentioned, in practice most problems encountered as a result of drought conditions centre around an energy shortage and lactating animals and young growing kids are the first to be adversely affected. Energy supplementation will therefore always be necessary for this group of animals first, followed by the other groups. The amount of energy supplementation will depend upon the animal's need, how much is provided by the grazing and the level of production that must be maintained - the latter will be mainly determined by economic considerations.
It must be mentioned that energy supplementation has this disadvantage - it usually lowers the animal's intake of natural grazing, in other words it replaces the intake of a portion of the natural cheap feeding material. Although this problem as such cannot be eliminated, the effects can be minimised by avoiding lengthy periods of low-level energy supplementation. Periods of energy supplementation can preferably be shortened, but at a high nutritive level so that the reaction aimed at by supplementary feeding can be achieved. As a general guide it is recommended that adult animals receive for instance 300 grams or more of mealies (or mealiemeal) per day, and kids 200 grams or more. In this respect the farmer will have to constantly evaluate the condition and performance of his animals in order to maintain the desired level of nutrition.
The use of roughage to supplement natural grazing is not recommended because it leads to a direct replacement of the natural grazing intake. Roughage must therefore rather be reserved for when animals must be withdrawn from the veld and when balanced rations must be made up. Roughage is invaluable for this purpose.
As far as protein is concerned, a marginal deficiency may occur during a serious drought among animals with a high requirement such as lactating ewes and kids. In normal circumstances this deficiency is corrected through the use of urea or licks containing urea and concentrates. Should animals be removed from grazing, sufficient natural protein will have to be incorporated into the ration.
In practice additional or supplementary feeding can be done in two ways, namely in the form of a lick where salt is used to control intake, or otherwise to provide additional feed only on a limited basis. Both methods have practical advantages and disadvantages, and the farmer must decide for himself which method will best suit his particular circumstances. In the case of licks, the frequency of replenishment is less, while good facilities (suitable lick troughs) are required to limit loss through wind and rain.
Where limited additional feeding is practiced replenishment is more frequent and cheep containers can be used because the limited amount of supplement which is fed is quickly eaten up. Whichever method is used, the most important aspect to bear in mind is the actual amount that the animal consumes.
In South Africa the most important source of energy for supplementary feeding is undoubtedly yellow mealies. The only problem which is generally encountered when it is used for drought feeding is that it can cause digestive upsets and even acidosis should animals ingest too much. This problem can be overcome by treating the mealies prior to feeding to the animals according to the chocolate mealie recipe, which has proved to give the desired result. When drought conditions are fairly serious and it becomes necessary to allow a relatively high intake, this method of supplementary feeding will be appropriate.
The level of supplementation followed will naturally be largely determined by economic considerations, in other words, if animals must be fed only for survival, for maintenance or for production. At the present stage the mohair industry is in a favourable position and it will undoubtedly be profitable, at least as far as reproductive ewes and kids are concerned, to feed for full production. Apart from the economic benefit to the farmer, it is also in the interest of the industry as a whole seeing that it will help to maintain the desired kid and young goat to adult mohair ratio.
Should a drought reach the stages where goats can no longer be kept on the veld in spite of additional feeding, then the animals will of necessity have to be kept in pens and fed on a complete balanced ration. The ration used will mainly be determined by the type of roughage and concentrate which is available. For this purpose it would be advisable to obtain the necessary information for the correct composition of a ration from a nutritionist.
Lastly, it must be mentioned that no cheap method of supplementary feeding for production during droughts exists. The primary goal in such circumstances must be to prevent the detrimental effects of a drought being carried over to the following more favourable years.
Angora goat and mohair journal 25 (2)