Feed ingredients that farmers use during drought periods may have detrimental effects on livestock if processed, stored or used inappropriately.
Some farming areas in Namibia are faced with severe forage scarcity, especially grazing materials, due to overgrazing and drought conditions.
Agribank’s technical advisor for livestock and rangeland, Erastus Ngaruka, said, in addition, the situation may further deteriorate if the anticipated rainfall is not favourable.
“Existing conditions and scarce options for alternative grazing have prompted many farmers to adopt the most obvious drought management strategy, which is to feed their animals.”
He said farmers are now battling to source a myriad of feed ingredients for their livestock to survive until grazing conditions become favourable.
“To this end, there are various feed resources in the form of crops and their residues, commercially formulated feeds and processed forage feeds, which include bush, pods and pasture, among others, that farmers can use.”
Ngaruka, however, warned that there have been several cases in which livestock became sick or died because of improper feeding practices.
Some of the suspected or observed health conditions include acidosis, pulpy kidney, listeriosis, and urea poisoning, among others. These can result mainly from overfeeding, improper processing and mixing, and feed spoilage.
According to Ngaruka, overfeeding occurs when an animal excessively eats a particular feed.
The main factors leading to overfeeding include hunger, free access and an oversupply of feed.
He said given the drought and insufficient forage materials, animals will have a higher feed intake than normal when introduced to supplementary feeds.
Range of diseases
The most common disease affecting goats and sheep resulting from overfeeding or a sudden change in their diet is enterotoxemia (pulpy kidney).
The disease is caused by bacteria that live in the animal’s digestive tract. When a digestive disturbance or sudden change in the digestive environment occurs, the bacteria proliferate and produce toxins that poison the animal.
This disturbance or change can come from changing diets and deworming animals.
“This means animals need to be first vaccinated against pulpy kidney before these changes.”
The symptoms include depression, abdominal pain, convulsions, and lying on the side, among others. Treatment with antitoxin may not be successful, but an annual vaccination is necessary for prevention. The other health conditions resulting from overfeeding include bloat and acidosis.
A bloat occurs when the ruminal gas accumulates at a higher rate than can be released, causing the stomach to distend or swell. Bloat can result from overeating lush feeds or fresh legumes, wet grass pastures or finely ground grains.
“This is a painful condition, and the symptoms include restlessness, abdominal discomfort, excess salivation, respiratory distress, and belly kicking, amongst others. On the other hand, the causes of bloat are also associated with acidosis.”
Acidosis is a metabolic disorder resulting from overeating grain feeds or easily digestible feeds, which in turn increases the acidity of the stomach.
The normal range of stomach acid (pH) levels is 6.5 to 7.0. With acidosis, the pH level drops below 5.5. This causes abdominal pain, loss of appetite and dehydration. In acute stages, both bloat and acidosis can be deadly.
Be aware and prepare
Ngaruka said the improper mixing of feeds poses danger to animals, especially when certain ingredients in the rations contain potent substances.
He said the most common feed ingredient during the dry season is urea, which is used as a protein source for the rumen microbes so that they efficiently digest the feed.
“Urea can poison the animal if ingested in large amounts. This can happen when an animal picks up pieces of urea that are concentrated in one spot in the feed. On the other hand, urea dissolves easily in water; thus, when a urea lick gets wet, an animal can be poisoned when it drinks the standing water in the lick trough.”
Ngaruka also warned that spoiled or contaminated feeds also pose a health hazard that can be attributed to improper storage of feeds.
He said feed storage is a drought preparedness practice, as farmers are acquiring feed in bulk in order to build up their fodder banks.
[Source – Republikein]