Ruminal Tympany (Bloat, Hoven)Ruminal Tympany (Bloat, Hoven)• Normally, microbial fermentation continually generate a

prodigious volumes of gas in the rumen that is eliminated by eructation or belching,.

• Anything that interferes with eructation will cause major problems for a ruminant called ruminal tympany or, simply, bloat.

• The disorder is perhaps most commonly seen in cattle, but certainly is not uncommon in sheep and goats.

• Tympany is characterised clinically by: Elevated extended hunger fossa. Progressive Dyspnea and discomfort. Finally death due to respiratory failure.

Bloat: Contributing FactorsBloat: Contributing Factors

1. Animal factors: It may be hereditary in some spp.

2. Dietary factors.Substances in the plant material make

rumen fluid thicker and more viscousGrains (barley, wheat, soybeans)Particle sizeRate of change

3. Microbial

Bloat: Contributing FactorsBloat: Contributing Factors

3. MicrobialFoaming agents (polysaccharides)

contained in rumen bacteriaFluctuations in rumen environment

(grain feeding) = ↑ cell ruptureSubstances released by bacteria make

rumen fluid thicker and more viscous

PathogenesisPathogenesis• Bloat is the overdistension of the

rumen and reticulum with gases derived from fermentation.

• Two types of bloat are observed, corresponding to different mechanisms which prevent normal eructation of gas:

11 . .Frothy bloatFrothy bloat (primary tympany) (primary tympany)• In which gases are trapped in a stable,

persistent foam which is not readily eructated.

• As quantities of this foam build up, the rumen becomes progressively distended and bloat occurs.

• Bloat on pasture is frequently associated with "interrupted feeding" - animals that are taken off pasture, then put back on, or turned out on pasture for the first time in the spring.

•

PathogenesisPathogenesis• This type of bloat occurs most commonly in two settings:1. Pasture bloat : Occurs on pasture, those containing alfalfa or clover

that are rapidly digested in the rumen, results in a high concentration of fine particles that trap gas bubbles.

Additionally, some of the soluble proteins from such plants may serve as foaming agents.

1. Feedlot bloat Animals feed high levels of grain, especially when it is

finely ground results in rapid digestion and an abundance of small particles appear to trap gas in bubbles.

Additionally, some spp. of bacteria that are abundant in animals on high concentrate rations produce an insoluble slime that promotes formation of a stable foam

22 . .Free gas bloat (secondary tympany)Free gas bloat (secondary tympany)• Occurs when the animal is unable to eructate

free gas in the rumen ??. Obstructive bloat: The conditions that partially

obstruct the esophagus (foreign bodies, abscesses, tumors) or interfere with rumenoreticular motility (i.e. reticular adhesions, Vagus indigestion) clearly can be involved.

Posture bloat: Another cause of free gas bloat that in which a ruminant cannot eructate when lying on its back, and if a cow falls into a ditch and is unable to right itself, she will bloat rapidly. Ruminants that are to undergo surgery in dorsal recumbancy should be starved for 12 to 24 hours prior to surgery, to avoid posture bloat during surgery.

PathogenesisPathogenesis• Regardless of whether bloat is of the

frothy or free gas type, distention of the rumen compresses thoracic and abdominal organs.

• Blood flow in abdominal organs is compromised, and pressure on the diaphragm interferes with lung function.

• The cause of death is usually hypoxia due to pulmonary failure.

DiagnosisDiagnosis• History: Bloat is an acute disease with a

short course, commonly manifest as sudden death, in unoticed animals.

• Clinical signs: Diagnosis of bloat is typically simple, and the clinical picture largely reflects how long the condition has existed.

• Palpation and percussion findings.

Clinical Signs includeClinical Signs include : :• Abdominal distension onto the left side. As

distention continues, the entire abdomen may become distended.

• Reluctance to move and cessation of feeding • Signs of distress: anxiety and vocalization • Respiratory distress: rapid breathing, neck

extended with protruding tongue.• Staggering and recumbancy: once a animal

with bloat is recumbant, death occurs rapidly.

• Although bloat is primarily an acute disorder, chronic, recurrent forms are recognized in calves.

Free gas TympanyFree gas Tympany

Frothy Tympany assoc. Vagus indigestionFrothy Tympany assoc. Vagus indigestion

Dwarf with BloatDwarf with Bloat

Tympany in goatTympany in goat

Frothy tympany in goatFrothy tympany in goat

Tympany in camelTympany in camel

Post-mortem findingsPost-mortem findings• Obvious distension of the rumen is certainly observed in

animals that die of bloat, but also occurs rapidly after death from almost any cause in ruminants, and is not a useful diagnostic lesion.

• Animals that die from bloat is ch. by congestion and hemorrhages in the cranial thorax, neck and head, and compression of the lungs.

• Pressure from the distended rumen leads to congestion and hemorrhage of the esophagus in the region of the neck, while the esophagus in the thorax is pale.

• Bloat line :Demarcation between congestion and pallor seen in the region of the thoracic inlet

• Usually, the liver is also pale because of displaced blood and interruption of blood supply.

Postmortem bloatPostmortem bloat

Bloat lineBloat line

Treatment and ControlTreatment and Control• Bloat is a life threatening condition and must be

relieved with haste باستعجال.• For animals in severe distress, rumen gas should be

released immediately by emergency rumenotomy. • Insertion of a large bore rumen trochar through the

left flank into rumen is sometimes advocated, it is often complicated with peritonitis.

• In less severe cases, a large bore stomach tube should be passed down into the rumen.

• Free gas will readily flow out the tube, although it may need to be repositioned repeatedly to effectively relieve the pressure.

• .

Treatment and ControlTreatment and Control• In the case of frothy bloat, antifoaming

medications can be delivered directly into the rumen through the tube; with close observation to insure that the treatment is effective and the animal begins to belch gas, otherwise a rumenotomy may be indicated

• Antifoaming agents to relieve frothy bloat include:

Vegetable oils (corn, peanut) or mineral oil, which are administered in 100-300 ml volumes to cattle.

Effective commercial antifoam as polaxalene (a surfactant) or alcohol ethoxylate (a detergent).

Trocer and canulaTrocer and canula

Frothy tympanyFrothy tympany

Frothy R. contentFrothy R. content

Trocerization of left flank in camelTrocerization of left flank in camel

ControlControl

• Control of bloat relies on management coupled with medications,

• Also, some of the techniques advocated may be applicable to small herds, but are too labor intensive to use with large herds.

• Many of the techniques used are based on reducing the rate of fermentation that occurs in the rumen.

• Examples of control strategies include:

ControlControl

1. Maintain pastures that have grasses mixed with legumes such as alfalfa

2. Feed animals hay before turning out on bloat-inducing pastures

3. In feedlots, feed roughage such as straw or grass hay in addition to concentrate

4. For animals on high grain rations, the grain should be cracked or rolled rather than finely ground

5. Apply antifoaming agents prophylactically, either by drenching individual animals, incorporating into feed, or spraying on small pastures

Bloat: Preventive MeasuresBloat: Preventive Measures• Ionophores: Antibiotics feed additive (e.g

monensin (Rumenson ®), lasalocid (Bovatec®), and laidlomycin (Cattlyst)

• It alter the flow of cations across cell membranes leading to reduction in G +ve bacteria which cause the bloat and other digestive problems associated with high carbohydrate diets.

• Surfactants: mineral oil ↓ activity for microbial bloat

• Nutritional management: longstemmed grass hay, probiotics