Bloat in sheep, cows and goats

What is bloat?

Bloat is a dangerous buildup of gas in the rumen (first stomach). Ruminants produce large volume of gas during the normal process of digestion. This gas either is belched (burped) up or passed through the gastrointestinal tract naturally. Bloat can occur from a build-up of foam which is called a frothy bloat, otherwise from gas which is called free-gas bloat.

Frothy bloat occurs after rapid engorgement of high protein, highly digestible feed (lush, young pasture or legumes like clover and lucerne) which results in formation of excess amounts of stable foam in the rumen. Gas is trapped in small bubbles in this foam in the rumen and the animal cannot belch up the gas. Free- gas bloat occurs when any physical (obstruction) or functional problem prevents normal belching (burping) of the gas.

Cattle often develop bloat when laying down because it is difficult for cattle to burp unless positioned upright.

Frothy/pasture bloat is common in New Zealand and Australia due to high content of clover.

Signs of bloat-

Frothy bloat usually occurs within an hour of feeding and free gas bloat happens sporadically.

Clinical signs-

·         Distended left abdomen but can be whole abdomen

·         Not grazing

·         Reluctance to move

·         Uncomfortable- restless, kicking at stomach, vocalising

·         Straining to urinate and defecate

·         Rapid/ trouble breathing

·         Falling down or sudden death in severe cases

How is bloat treated?

Please contact your veterinary straight away if you are not experienced in dealing with bloat, before giving any at home treatment!!

Cattle-

All animals should be moved off the offending pasture immediately and caution should be taken when moving or handling animals with bloat, as this may cause collapse and death from cardiac and/or respiratory failure. For cattle in distress but not life-threatening it is best to treat with an oral drench with a proprietary pluronic or alcohol-ethoxylate based bloat drench. If still current after 1 hour a further dose may be given. Paraffin or vegetable oils (500mls) are also very effective. A trocar and cannula inserted into the rumen can release gas and a stomach tube may be inserted to help deliver anti-foaming agents directly into the rumen. However, this is only useful in mild cases of frothy bloat and in the case of a life-or-death situation an incision/ scabbing (which is called a rumenotomy) may be required in the hope of survival. Bloat wounds are always contaminated and should be treated with antibiotics.

Sheep and goats-

Just like in cattle if your sheep or goat is displaying signs of bloat you can give them a drench if you are experienced enough to do so. If in doubt, please consult your vet and do not drench your animal if not experienced as this can cause more healthy issues- drenches can include.

·         110-200mls of any non-toxic vegetable or mineral oil

·         A proprietary non-ionic surfactant polymer bloat drench (bloat guard, agrimi)

·         8-10ml medical turpentine in 100mls paraffin oil

·         15-20ml turpentine in 100-150ml linseed oil

·         In an emergency, 10ml washing up liquid will suffice.

Massaging the abdomen to spread the oil. A vet may insert a trocar or 14-16g needle into the rumen on the left-hand side to help release the gas and an oil or bloat remedy can be introduced directly into the rumen through a cannula. A stomach tube can also be passed to help release gas.

Prevention-

·         Monitor animals carefully for the first 12 hours after access to the pasture

·         Allow only limited access to grazing or strip-grazing: move animals onto the pasture in the afternoon, not the morning, so the animals have already eaten. Feed hay, silage or non-legume pasture in the morning before moving

·         Frost increases the risk of bloat, so remove the animals before any frosts occur

·         The bloat risk is low in fields containing less than 50% legume

·         Wilting the forage significantly recues the risk of bloat so “cutting and carting” or allowing the animals to eat wilted forage off the ground is beneficial

·         Avoid any sudden introduction of fermentable material to the diet and provide sufficient fibre in the form of hay

·         Smearing vegetable oil on the coat before grazing will promote a regular intake of oil by licking so preventing gas build up

·         Do not feed bottle fed lambs warm milk or mixing milk replacer with warm water as it is a major risk factor for abomasal bloat Only mix tap water to bottle fed with