Supplementation feeding considerations
Beef cattle production in Queensland is based predominantly on native pastures. Few cattle are fed supplements due to the high cost and poor return under normal seasons, however there are exceptions.
Recent research has demonstrated the benefits of 'spike feeding' Zebu cross breeder cattle during the last six weeks of pregnancy to stimulate higher fertility in the cow post calving. Other exceptions are in areas where a gross deficiency of a trace mineral has been observed. In some cases, correction of the deficiency can be achieved by the use of a single dose administered orally or by subcutaneous injection.
Common problems throughout Queensland are the high freight component of supplementary feeds and providing an effective adequate dose to all animals.
Hence, supplementary feeding is often difficult to justify. Occasionally there may be an opportunity to use supplementary feeding to provide weaners with a coccidiostat. Apart from supplementing cattle on crop with grain, it is seldom worthwhile feeding supplements in order to increase weight gain.
Supplementary feeding under dry conditions should only be considered after implementing serious management decisions regarding the sale of infertile and low fertility animals, the segregation into classes of susceptible groups of animals and strategic weaning of calves. Supplementary feeding is an expensive way to counter overstocking.
Supplementary feeding for maintenance and survival is, however, a regular occurrence in many parts of Queensland and can be for long periods.
The availability of RAINMAN and predicted climatic responses using the Southern Oscillation Index provide producers with indications of rainfall probability for the ensuing periods. These tools, coupled with husbandry practices, enable the producer to start destocking before large scale supplementary feeding of the herd.
There are many feeds available to the producer, with more emphasis placed on some rather than others depending upon the area where the feed is produced. Stocks of some feeds can end up being in short supply more quickly than others, thus limiting them as an effective option.
Early stages of feeding
As seasons start to deteriorate, there is generally an adequate availability of dry standing pasture or roughage. The pastures are initially deficient in phosphorus and sulphur, with a subsequent decline in protein and digestibility. Cattle will respond to supplements supplying adequate levels of each. A 250 kg animal will require approximately 200 g digestible protein, 8 g phosphorus and 5 g of sulphur per head per day. Feeds that are commonly used fit into the following categories.
There are a large number of proprietary blocks available on the market. They consist of varying levels of molasses, salt, urea, minerals, grains and other minor additives and are convenient to feedout. However, not all blocks are the same weight, and nutrient content.
There is considerable variation in the value per unit of the nutrients that animals require. There are often high levels of salt, which may reduce palatability of the block to stock in certain areas. These blocks have recommended daily intakes often varying between 60 to 150 g/hd/dy.
Blocks should be firm so that stock cannot eat large pieces, which may be toxic to some animals.
They have relatively low energy levels. Blocks should be judged and their cost compared on the basis of their total nitrogen or phosphorus content, depending on the purpose for which they are being fed.
One disadvantage of blocks is that the intake of cattle cannot be regulated by changing the proportion of the various ingredients as in home mixes.
The type and amount of ingredients vary almost as much as with proprietary blocks, depending upon the conditions under which they are to be used:
- Dry mixes
- often use salt to regulate the intake by stock
- may include salt, phosphorus, urea, GranAm and vegetable protein meals
- Molasses based mixes
- may be required as a carrier in the mix or to entice animals to start to lick it.
- molasses plus 8% urea (M8U)
- molasses plus 10% vegetable protein meal plus 2% urea.
Some tips about these ingredients:
- urea is not very palatable but can be toxic
- molasses enhances palatability.
- feeding is carried out using either roller drums or in open troughs with or without some intake regulatory mechanism.
- the aim is for breeders to consume about 60 g of urea per head per day.
- vegetable protein meals may include cottonseed meal, peanut meal, linseed meal, safflower meal or soya meal.
- many vegetable protein meals may be fed on their own or in addition to molasses.
- molasses may be used to encourage stock to eat a particular supplement, particularly in areas where the drinking water is high in salt.
Later stages of feeding
As pasture is exhausted, there is an increasing need for feeds that supply both protein and energy. The greater the decline in dry standing grass, the greater the benefit from additional hay and the greater dependence on fodder trees if available.
Protein and energy are often supplied through the use of grain and molasses. Grains vary in levels of protein, but are one of the better sources of energy. Whole cottonseed provides adequate levels of protein and is a good source of energy. Cattle appear to self-regulate their intake on whole cottonseed, which minimises engorgement. Many of the other grains can be difficult and dangerous to feed.
Cattle will die if their intake of grain increases rapidly without a gradual period of adaptation. Under drought conditions cattle have been kept alive with grain fed in small quantities on the bare ground. Sorghum, oats, wheat and barley are commonly used, but care must be taken when feeding wheat. When changing the grain diet, it should be done gradually.
Molasses is the cheapest source of energy. One kilogram of molasses is equivalent to about 0.7 kg of grain and is very safe. Molasses in itself contains virtually no protein and hence the need for some additional protein in the form of either urea or vegetable protein meal.
Urea is a cheap source of protein, but can be dangerous. It must be mixed thoroughly with the molasses.
Molasses will corrode concrete and galvanised iron tanks or troughs and should be stored in either fibreglass tanks or the tanks treated appropriately with an epoxy-based paint.
As dry standing feeds are exhausted, the cattle will require additional roughage. Hay should be assessed not only on the dollar per tonne price but also on the nutrient content and digestibility.