Livestock diseases

Signs of sickness and major diseases

A sick animal is dull, separates from the herd, eats little, stops rumination (chewing the cud), has a dry muzzle, abnormal temperature (normal for cattle is about 38.5 °C), changed dung or urine, rough coat and a sudden drop in milk. Sick animals should be isolated and treated by a veterinarian; vaccination prevents many diseases.

Cattle and buffalo diseases:

• Rinderpest (cattle plague): viral; high fever, erosions in the mouth, severe diarrhoea, high death rate. It has been eradicated worldwide (declared in 2011).
• Foot-and-mouth disease (FMD): viral, highly contagious; fever, blisters in the mouth and between the hooves, drooling of saliva, lameness, fall in milk yield. Affects cloven-hoofed animals. Prevented by vaccination; wounds are washed with mild antiseptic such as potassium permanganate solution.
• Black quarter (BQ): bacterial (*Clostridium chauvoei*); usually young cattle of 6 months to 2 years; hot painful swelling in heavy muscles of the hind or fore quarter that crackles when pressed (gas under skin); lameness; often fatal.
• Haemorrhagic septicaemia (HS): bacterial (*Pasteurella multocida*); common in buffaloes in the rainy season; high fever, swelling of the throat region, difficult noisy breathing; death may be quick.
• Mastitis: inflammation of the udder, usually bacterial; swollen, hot, painful quarter; clots, flakes or blood in milk. Prevented by clean milking, full milking and teat dipping; detected by tests such as the California Mastitis Test.

Poultry diseases:

• Ranikhet disease (Newcastle disease): viral; respiratory distress, greenish diarrhoea, twisted neck and paralysis; high mortality. Prevented by vaccination.
• Fowl pox: viral; wart-like scabs on the comb, wattles and face (dry form) or lesions in the mouth (wet form).
• Coccidiosis: protozoan (*Eimeria*); young chicks; bloody diarrhoea, droopy birds; favoured by damp litter. Controlled with coccidiostats in feed and dry litter.

Key points

• Viral: rinderpest, FMD, Ranikhet, fowl pox.
• Bacterial: BQ, HS, most mastitis.
• Protozoan: coccidiosis.
• Rinderpest: globally eradicated (2011).

Exam tips

Classify each disease by cause and match key symptoms (crepitating swelling → BQ; twisted neck → Ranikhet; bloody droppings → coccidiosis).

Common mistakes

• Calling coccidiosis bacterial; it is protozoan.
• Confusing FMD blisters with fowl pox scabs.