Luo: ich-kuot / Embu: nunvita / Gabbra: furfur / Gikuyu: huhita / Kamba: kwimbanywa / Kipsigis: kowiren / Maasai: Embo'ngit, Ediis, empomgit / Maragoli: kuhaata, myika munda/ Meru: mpwna / Samburu: mberini / Somali: bakhakh, dunbudhyo, balao, baalallo, dhibir, dibiyio / Turkana: lotebwo, akitebukin, akiurur / Pokot: lesana /
Other name: Ruminal Tympany
With the onset of long rains, livestock keepers, especially goat, sheep and cattle keepers should become aware of the dangers of bloat to their livestock. Bloat occurs when there is an abrupt nutritional change in the diet and especially when ruminants feed on lush green pastures. It simply means animals have too much gas in their stomach.
|Cow with bloat
© W. Ayako, KARI Naivasha
|X-ray - dog with bloat
|© Joel Mills, Wikipedia
How animals get bloat
The rumen of cattle, sheep and goats is like a large container in which a mixture of partly digested feed and liquid is continuously fermenting, producing large quantities of gas. For example, an average cow can produce over a thousand litres of gas in a day. Some of the gas is removed by absorption into the blood stream but most of it is removed by belching during "cudding". If the gas cannot escape, the rumen literally "blows up" and the animal gets bloat. It can happen when:
- Animals eat too many legumes or too much fresh, lush grass (e.g. olenge grass (Luo))
- Animal eats too much grain (e.g. finger millet, Acacia pods)
- Animal eats cassava leaves or peels
Something blocks the passage of food in the stomach or gullet
Types of bloat
There are two types of bloat: Frothy Bloat and Free Gas Bloat.
Animals get Frothy Bloat when the rumen becomes full of froth (foam). Several animals in the herd may get this type of bloat at the same time when they graze on wet, green pasture mixed with legumes in the field. Foaming substances are found in certain plants such as legumes of which lucerne, clover and young green cereal crops are examples.
Frothy Bloat is due to the production of a stable foam, which traps the normal gases of fermentation in the rumen. Pressure increases because belching cannot occur. Initially the distension of the rumen stimulates rumen movements, which makes the frothiness even worse. Later on because of the distension there is loss of muscle tone and loss of the rumen's ability to move spontaneously, compounding the situation.
Saliva has antifoaming properties. More saliva is produced when food is eaten slowly than when it is eaten quickly. Succulent forages are eaten more rapidly and digested more quickly and as a result less anti-foaming saliva is produced. Grazing on immature, lush, succulent, rapidly growing pastures with a high concentration of soluble proteins is most conducive to bloat, as is the stage of growth of the plant, not its degree of wetness.
Causes of Frothy Bloat
- The primary cause of frothy bloat appears to be a change in the composition of certain pasture plants, the change being one that facilitates the development of a stable foam that in turn prevents belching
- Frothy Bloat normally happens at the start of wet season when the diet of grazing animals abruptly changes from dry feeds to wet lush pastures that contains some legumes.
- Animals also get Frothy Bloat when they feed on ripe fruits or other feeds that ferment easily.
- Some poisonous plants can cause sudden and severe bloat.
- A sudden change in the type of food can also cause Frothy Bloat.
Frothy bloat can also occur in feedlots with insufficient roughage, or food too finely ground. This leads to a shortage of rumen-stimulating roughage, and prevents the rumen's ability to move spontaneously and hinders belching and release of gas.
Free Gas Bloat is usually due to physical obstruction of the oesophagus, often by a foreign body such as a potato, avocado, apple etc. Grain overload leading to stopping of of normal rhythmic contractions of the rumen wall can also cause this type of bloat as can unusual posture, particularly lying down, as may occur in a cow affected by milk fever. This type of bloat normally only affects one or two animals in the herd at the same time, not several as in the case of Frothy Bloat. As the name suggests, in this type of bloat the gas lies above the food in the rumen and is not mixed with it, as it is in Frothy Bloat.
Signs of Bloat
- The left side of the abdomen behind the ribs becomes very distended and very tense, like a drum. Later the right side also becomes distended
- The animal stops eating
- The animal may grunt and have difficulty in breathing
- There may be mouth breathing
- The animal may stamp its feet on the ground
- Sometimes green froth comes out of the mouth and nose
- There may be extension of the tongue from the mouth
- Diarrhoea is common in cases of Frothy Bloat
- Animals may collapse and die after only an hour or so
There is often frequent urination
Prevention - Control - Treatment
Prevention of bloat
1. Feed the animals with dry grass or hay to fill them up before you turn them out onto new wet lush pasture. For this to be effective the hay or dry grass should form at least one third of the diet.
2. Do not water the animals just before you put them on to wet pasture
3. Do not graze the animals on wet green pasture early in the morning. Wait until the pasture has been dried up by the heat of the morning sun
4. You should gradually increase the grazing hours of the animals on wet green pasture over the first week. Do not put the animals out all day and leave them there.
5. Avoid abrupt changes in the diet of animals and always give newly introduced feeds in small quantities.
6. If possible try to strip graze animals to reduce intake and to maintain grass dominance in the stretch of grass. The pasture ideally should have at least 50% grass.
7. During the risk period the continual administration of anti-foaming agents such as Stop Bloat should be considered.
8. Watch animals closely at all times during the risk period.
9. Keep anti-foaming agents close at hand during the risk period.
10. In feedlot or zero grazing situations rations must contain 10-15% chopped roughage mixed into the complete diet. This should be a cereal, grain straw, grass hay or equivalent. Grains should be rolled or cracked, not finely ground.
Treatment of bloat
Depending on the type of bloat, several methods of treatment can be applied:
- Do not feed the animal for a few hours and make the animal move around (remember it can die within 1 hour if the bloat is severe)
- For less severe cases of frothy bloat, give 500ml to large animals and 100ml to small animals of any edible vegetable oil, solid cooking oil, butter oil, ghee or milk orally (by mouth). Non-toxic mineral oils can also be used effectively.
- Severe bloat is an emergency and rapid action is required to save the animal's life. In life-threatening cases where the animal can not breathe, an emergency rumenotomy may be necessary. Puncture carefully the skin and the rumen of the animal on the left flunk to let the gas out. Use a knife or any sharp thing but the best instrument to use is the trochar and cannula. The hole should be made at a hands' width behind the last rib and a hand away from the edge of the backbone. Push hard because the skin is very tough. Gas and froth will come out when you make the hole. It helps to put a tube or cannula through the hole to keep the hole open. There will be an explosive release of gas and rumen contents. Remember that in severe cases if this is not done the animal will die. SO DO IT (for more information on how to use a trocar please also see Tools for livestock)
- Pour some vegetable oil into the rumen through the hole to help stop further gas or froth formation. Complications are rare. Call a veterinarian to attend to a punctured abdomen or a difficult case of bloat.
- Another aid is to tie a stick in the mouth to stimulate the flow of saliva, which is alkaline and helps to denature the foam.
- Forceful walking may help to coalesce the foam into larger bubbles and stimulate belching.
- Give bloat medicine such as the following: Stop Bloat, Bloat Guard or Birp once daily for 3 days
In cases of Free Gas Bloat due to a foreign body lodged in the oesophagus, it may have to be dislodged by using a probang or stomach tube, for which the services of a veterinarian will be required.
Common traditional practice
Some of the following practices may have some merit in case of emergencies where no vegetable oil is available:
- Gabbra: Mix 4 teaspoons of laundry detergent with 1 litre of milk. Drench 1 litre for an adult cow (0.5 litre for sheep and goats)
- Turkana: Mix 500g Magadi soda with 1 litre of water. Stir well and drench adult cattle with the mixture. For calves, goats and sheep use 0.5 litre. For large camels give 2 litres.
- Luo: Mix 0.5 litre of paraffin oil with a handful of olulusia (Vernonia amygdalina) leaves and 2 spoons of salt. Drench with half this amount.
- Kamba: Mix a handful of wood ash with 1 soda bottle (300ml) of water. Sieve and drench adult cattle with this amount. Use half the amount for calves, sheep and goats.
(Source:ITDG and IIRR 1996)