Preventing Health Problems When Supplementary Feeding
When beginning a supplementary feeding program it is important to ensure health problems that can be associated with supplementary feeding are prevented. This article details common health problems that should be considered when feeding and their prevention.
Chemical residues
As feed is often in short supply during times of drought, cattle often put in paddocks or fed crop residues that are not normally used. This can lead to an increase in the problem of chemical residues.
The following points may help to minimise the risk from chemical residues:
- Use registered chemicals and veterinary drugs according to label instructions. Contamination can occur by using banned chemicals, by incorrect use of registered chemicals or by not observing correct withholding periods and export slaughter intervals.
- Do not feed stubble or other residue from crops that have been grown on land previously treated with organochlorines.
- Feed stubble or other residue from crops treated with pesticides only after the withholding period has expired.
- Purchase fodder from a reputable source. If possible, obtain an enforceable guarantee that it is free from residues and/or a vendor declaration.
- Beware of grain storage facilities with concrete or earth bases, particularly those that have been treated with organochlorines. These areas may be a source of contamination.
- Clean up loads of grain containing a significant amount of dust. They may have very high levels of contamination.
- Do not hold cattle in yards treated for white ants, particularly where organochlorines have been used.
- Pay careful attention to disposal of old chemical containers and prevent cattle from entering disposal areas.
- If there is any doubt about the chemical status of feed or soil, have tests carried out before cattle are fed or grazed. Contaminated soil can cause residues in grazing cattle as the cattle will eat dust on plant material.
Animal health
The fodder must not be toxic or harmful at the desired feeding levels. Table 1 shows some of the common health problems associated with feeding drought fodders, and the methods of minimising these problems.
Table 1. Health problems and their prevention
| Problem | Prevention |
|---|---|
| Grain poisoning (acidosis) | Introduce grain gradually and make any changes gradually as well. Feed only maintenance levels unless a decision has been made to feedlot fatten. The addition of bentonite and sodium bicarbonate reduces acidosis. The order of safety with common grains is sorghum, maize, barley, wheat. |
| Urea poisoning | Introduce urea gradually. Mix urea thoroughly. Prevent rain contamination. Keep antidote (vinegar) on hand. |
| Plant poisoning | Avoid fodders containing poisonous contaminants. |
| Mouldy hay | Avoid feeding mouldy hay. |
| Digestive system obstructions | Feeding whole vegetables can cause obstructions in the gut. It may be necessary to chop whole vegetables into pieces. Feeding scrub for prolonged periods gives rise to impaction of the digestive system with dry stems and leaves. This can cause a slowing of the digestion and sometimes a blockage. The problem can be minimised by feeding supplements such as molasses and by cutting more scrub thereby increasing the proportion of leaf to stem in the diet. Baling twine and plastic bags, if left in the feeding area, can also cause gut obstructions. |
| Gossypol poisoning | The feeding of high levels of whole cottonseed may cause toxicity. The general recommendation is not to feed more than 1% of body weight. |
| Pulpy kidney | Pulpy Kidney (enterotoxaemia) is often associated with drought feeding. Cattle should be vaccinated with 5-in-1 vaccine. |
| Pesticide residues | Extreme caution needs to be taken with `high risk' fodders. These are those fodders that have been grown where there is a history of pesticide use (especially organochlorines). The onus is on the vendor not to sell contaminated fodders. |
| Botulism | Botulism has been caused by the ingestion of fodders contaminated with dead birds and animals, or parts of dead birds and animals (for example, poultry, cane toads, rats, snakes). Care should be taken to avoid fodders likely to contain these contaminants. In high risk situations, animals should be vaccinated. |