Dreaded El Niño will flood animals with diseases, pests

El Niño rains are about to make a comeback, the Meteorological Department has raised the red flag. Indeed, above average rainfall have begun pounding some parts of the country.

If the predictions come to pass, most parts of Kenya will soon be soaked in torrential rains.

Rains alter the population and distribution of living things (animals and plants) and their surrounding environment. Increase in soil moisture will proportionately result in more vegetation cover and thus more feed for herbivores.

But be warned. A lot of rainfall can have a negative effect on the health and productivity of your livestock.

In the same breath, populations of arthropods and insects, some of which are infectious disease-spreading agents, will flare-up.

In rainy seasons, diseases and disorders will either result from the presence of pasture or the disease-causing and transmitting agents.

When rains come after a prolonged dry season, they normally trigger off immediate sprouting of lush vegetation which livestock find appetising. They will thus consume large quantities. If this feeding behaviour is not controlled, it can result in pasture bloat, grass staggers or lush pasture diarrhoea which are fatal diseases if not appropriately managed.

Pasture bloat

This is a digestive disorder of ruminants caused by accumulation of fermentation gases — predominately methane and carbon dioxide — in the first two compartments of the stomach.

Under normal circumstances, these gases are expelled through a physiological process called belching. This process can be impaired when an animal consumes a lot of pasture that is low in fibre but high in digestible component.

It has commonly been observed in young legumes like alfalfa and clovers. These feeds form frothy foam that holds onto these gases in form of small air bubbles that exert pressure in the two stomachs and hinder breathing.

Death results from suffocation and can happen within 20 minutes. This condition is common in hungry and aggressive feeders suddenly introduced to green pasture fields.

Bloat can, however, be easily relieved by a veterinary surgeon. It can also be prevented by the farmer.

To prevent bloat, avoid sudden introduction of your stock to young leguminous pastures. Instead, mix green pastures with fibrous feeds like dry grass hay. A farmer must carefully observe his animals for bloat, which is characterised by sudden distention of the stomach (especially the left side), restlessness, difficulty in breathing and belly kicking.

The animals can be fed on hay or other dry feeds before moving them into green pastures.

If you observe these signs, immediately remove the animal from pasture and give it dry hay. Gently force it to walk as this stimulates belching.

There are many anti-bloat supplements and liquids in the market. Other relieving operations like stomach tubing can be done by a veterinary surgeon.

Lush pasture diarrhoea

Change in diet can cause diarrhoea in animals, especially calves, sheep and goats. Diarrhoea has been linked to the presence of digestive system irritants in lush pastures hence the name.

Grass staggers

Also known as grass tetany, this is a metabolic disease caused by the deficiency of magnesium which is vital in proper functioning of many physiological body functions. Lush pastures lack magnesium which is also associated with the pasture soils. Grass staggers is very common in older milk-producing animals.

Livestock with this condition will suddenly stop grazing and their heads and ears will remain constantly erect. They will also be generally restless and can collapse and die without showing any clinical signs.

To prevent grass tetany, animals must be given mineral lick supplements. Forage legumes like clovers and alfalfa normally have high levels of magnesium and can be included in the feeding regime to reduce incidents of grass tetany.

Rift Valley Fever (RVF)

Besides such diseases caused by sudden abundance of lush green pastures, the advent of El Niño rains will increase their populations of disease causing and transmitting organisms, but negatively impact on livestock health and production due to flare up of diseases.

During wet and humid conditions, tick populations are known to increase.  It certainly follows that tick-borne disease incidences will increase with the rains. Farmers are therefore advised to spray their animals regularly.

Rift Valley Fever is a disease of great concern for farmers during El Niño rains. The disease affects cattle, sheep, goats and camels and can be spread to man. In animals, it is spread by mosquitoes. Humans get infected by contact with infected carcass or fluid from sick animals.

The disease follows a sudden increase in mosquito populations which are normally observed during prolonged rainy seasons or in areas where large pools of water are suddenly introduced like during the construction of dams or in irrigation fields.

The disease owes its name to Kenyan Rift Valley where it was first reported in 1910. Various outbreaks have since been reported across the globe. In Kenya, a notable outbreak occurred in 2006/07 following heavy rains in Garissa, Ijara, Baringo and Kilifi districts where thousands of animals and about 11 people died.

The Rift Valley Fever is normally characterised by abortions and deaths in young stock and sheep. Bloody diarrhoea, jaundice, depression, lack of appetite, excess nasal and eye discharge are other signs.

It is therefore a threat to livestock and farm hands and carcasses and aborted foetuses of suspected animals must be handled with a lot of care using protective clothing and disposed off by burial in a deep hole so that the carcass is out of reach by dogs and other carnivores.