Any alteration in state of the body of an animal or its organs which interferes with proper performance of its functions.


Visible signs of a disease.

Specific conditions that are observed. 

  • Pulse rate and respiration rate.
  • Body condition.
  • Visible mucous membrane.
  • Skin of the animal.
  • Defecation
  • Urination
  • Feeding/appetite.
  • Level of production.

Causes of diseases.


  • Protozoa
  • Bacteria
  • Virus
  • Fungui

Non pathogenic causes.

  • Poor nutrition.
  • Physical injuries.
  • Chemical poisoning.
  • Parasitic infestation.

Predisposing factors.

Conditions inside or outside the body of an animal that lead to the animal contracting a disease or injury.


  • Age of the animal.
  • Sex of the animal.
  • Colour of the animal.
  • Change of climate/environment.
  • Animal coming into contact with sick animals.



  • Incubation period.

Duration between the time of infection and when the first symptoms shows up.

  • Mortality

Likelihood of death occurring in a disease outbreak. Mortality rate is expressed as a percentage.

Mortality rate= (animals that die/animals affected) X100.

  • Treatment

Application of physical and chemical means to an animal to help it recover from a disease or prevent it from contracting a disease.


  • Preventive treatment.
  • Curative treatment.
  1. a) Curative treatment.

Tries to restores a sick animal back to health.  Include:

  • Good feeding.
  • Provision of a clean environment.
  • Neutralising the ill effects produced by the diseases.
  • Inducing repair of damaged tissues.
  • Reliving discomfort or injury to the animal.
  • Preventing further spread of the disease.
  1. b) Preventive treatment.

Involves administration of drugs to prevent occurrence of a disease. Include:


Use of prophylactic drugs e.g. coccidiostats to prevent Coccidiosis.

4) Immunity. 

Ability of an animal to resist the infection of a disease.

Types of immunity.

  1. a) Natural immunity/inborn immunity.

Ability of an animal to maintain itself free from infection.

  • Actively acquired natural immunity.
  • Passively acquired nature immunity.

Inherited immunity is acquired from parents to offspring.

Actively acquired immunity depends upon a previous attack.

Passively acquired immunity is passed through the mother’s blood, colostrum or milk.

  1. b) Artificial immunity.
  • Active artificial immunity.
  • Passive artificial immunity.

Active artificial immunity. Obtained when an animal resists a disease causing organism.

(Induces the body produce its own antibodies).

Passive artificial immunity. Anti-serum is injected to a healthy animal. (Dose not induce the animal to produce its own antibodies).


Preparations of dead or altered disease causing organism.

Vaccines stimulate an animal’s body to produce its own antibodies.



  • Protozoan diseases.
  • Bacterial diseases.
  • Viral diseases.
  • Nutritional diseases.


  • East Coast Fever.
  • Anaplasmosis
  • Coccidiosis
  • Tryposonomiasis(Nagana).


Animals attacked.


Causal organism.

Protozoan. (Theirelia parva).

Transmitted by brown ear tick. (Rhipicephalus appendiculatus).

Incubation period is 15 days.

Symptoms of ECF.

  1. Swollen lymph nodes especially around the base of ears, shoulders and stifle joints.
  2. Animal develops high temperatures (Fever). iii. Profuse salivation, production of a lot of saliva. iv.         Lachrymation, production of a lot of tears from the eyes.
  3. Difficulties in breathing especially at late stages of the disease due to fluid accumulation in lungs.
  4. Haemorrhages in the vulva and mouth. vii. viii. Sight impairment.

 Control and treatment.

  • Control of ticks through regular spraying, dipping or hand dressing using acaricides.
  • The farm should be fenced to keep out strange animals and confine animals within. Treatment using appropriate drugs.


Animals attacked.

  • Cattle
  • Sheep
  • Goats.

Causal organism.

Anplasma marginale.

Transmitted by:

  • Blue tick. (Boophilus decoloratus). S Hypodermic needle.

Incubation period is 3-4 weeks.


  1. Constipation/hard dung.
  2. Paleness in gums, eyes and lips in later stages, an indication of anaemia.
  3. Fever.
  4. Milk flow into the udder ceases hence production goes down.


Control and treatment.

  1. Control of ticks and biting insects such as mosquitoes and flies.
  2. Intramuscular injection of antibiotics and iron-giving injections.


Animals affected.

  • Young rabbits.
  • S Calves. S Kids.

Causal organism.

Coccidian of Eimeria species.

Coccidian infects the lining of alimentary canal.

Incubation period is 7 days for poultry and 4 weeks for cattle.


  1. Dysentery/blood in dung. iii. Animal becomes emaciated. iv. Birds have ruffled feathers.
  2. Birds become dull with dropping wings.
  3. Sudden death in birds, rabbits and kids.

Control and treatment.

  1. Isolation of infected animals in cattle. Use of portable calf pens is recommended,
  2. Use of coccidiostats drugs e.g., Amprol and Furexol for treatment and control.       Avoid wet, filthy and unhygienic animal surrounding. iv.     Avoid common watering points for cattle from different farms.
  3. Avoid overcrowding in poultry houses.


Animals affected.

  • Poultrey
  • Horses
  • Cattle
  • Sheep
  • Pigs.

Causal organism.

  • Trypanosoma spp.
  • Trypanosoma brucei brucei. S Trypanosoma evansi, horses.

Transmitted by a vector that is tstetste fly. Has an incubation of 1-3 weeks.


  1. High temperatures/fever. Intermittent body temperatures.
  2. The animal become dull. iii. Loss of appetite/anorexia. iv.     General body weakness.
  3. Swollen lymph nodes.
  4. Lachrymation that leads to blindness.     Diarrhoea. viii.            Coat is rough sometimes without hair and may be cracked. ix.    Swelling of parts of the belly.
  5. Milk production decreases,
  6. Loss of hair at tail end.
  • xiii. Abortion in pregnant females due to high temperatures.

Control and treatment.

  1. Treatment with trypanocidal drugs. ii. Effective control of tstetste flies. iii.           Confinement of game animals in game parks.



  1. Mastitis.
  2. Foot rot.
  3. Contagious abortion/brucellosis.
  4. Black quarter.
  5. Fowl typhoid.

1) Mastitis.

Infectious disease of mammary gland. May be acute or chronic.

Animals affected.

All animals with mammary glands. Cattle, sheep, goats, pigs, camel and horses.

Causal organism.

There are two types of mastitis.

  1. Streptococcal mastitis.

Streptococcal agalactiae.

  1. Staphylococcal mastitis.

Staphylococcus urens. 

Predisposing factors.

Older animals are more likely to be infected as compared to younger ones.

  1. Stage of lactation period.

Animals are likely to suffer from mastitis at the beginning and at the end of lactation.

  1. Udder attachment.

Animals with a long pendulous or loosely hanging udders and long teats are more susceptible. Such udders are liable to mechanical injuries.

  1. Incomplete milking.

Milk left in the teat canal acts as culture media for bacteria.

  1. Mechanical injuries.

Wound on teats or udder allow micro-organisms entry into the udder.

  1. Poor sanitation.

Increases the multiplication of bacteria.

  1. Poor milking technique.

May result in mechanical injury of the teats and weakening of sphincter muscles of the teat.


  1. Milk contains pus, blood, thick clots or turns watery. ii. When the udder and teat are swollen, animals reject suckling or milking and kicks due to pain.

iii.      Death of infected quarter may result. iv.        Milk has a salty taste and there are fine clots or flakes particularly the fore milk.

Control and treatment.

  1. The affected quarter of the udder is emptied of milk and an antibiotic is instilled.
  2. Use of the right milking technique.
  • After every milking, use teat dip on every quarter.
  1. Strict cleanliness and use of disinfectants during milking.
  2. Dry cow therapy. Infusion of long acting antibiotics into the teat canal when drying off the cow.
  3. A strip cup should be used to detect infection. Infected cows should be milked last. vii. Use separate udder clothes for each animal or disinfect after milking each animal.
  • Sharp objects should be removed from grazing and milking areas to prevent teat injuries.
  1. Open wounds on teats should be treated immediately. 


Animal affected.

Domestic birds: chicken, turkey and ducks.

Causal organism.

Salmonella gallinarum.


  1. Birds shows signs of depression. They appear obviously sick.
  2. Respiratory distress and are dull. iii. Drooping wings and sleepy eyes. iv. Combs and wattles become pale and shrunken because of anaemia.
  3. Greenish yellow diarrhoea.
  4. Birds dies within a few days.

Control and treatment.

  1. All affected birds should be killed and properly disposed off.
  2. Poultry house should be clean, dry and well ventilated. Regular vaccination. iv.          Eggs for hatching and chicks rearing should be obtained from reliable sources.
  3. Sulphur drugs mixed in water or mash for treatment. E.g. Furazolidone at 0.04% in mash for ten days.



Animals affected.

Infectious and contagious disease. Affect all cloven hoofed animals. Cattle, sheep and goats.

Causal organism.

Bacteria of Fusiformis family.

S Fusiformis necrophorus. S Fusiformis nodosus.

 Predisposing factors.

  1. Filthy surroundings such as wet and muddy areas. Wetness causes skin between the hooves to soften and get cut by objects.
  2. Overgrown hooves that leads to their cracking.


  1. The animal’s foot becomes swollen.
  2. There is a sign of pain as the animal walks making it limp. Lameness is observed.     Pus and a rotten smell from the hoof. iv.       When the front legs are affected sheep are found kneeling when grazing.
  3. Animals spend most of their time lying down when the hind feet are affected. vi. Animals become emaciated due to lack of feeding.


  1. Avoid dampness and muddy conditions.
  2. Regular foot examination and hoof trimming.
  • Practise regular walk through a copper sulphate foot bath at 5-10% solution or formalin 2-5% solution.
  1. Wounds should be treated with antiseptics.
  2. Healthy sheep should be moved to dry clean areas.


Animals affected.

Cattle, sheep, goats and pigs.

It is a zoonotic disease that is contagious and infectious.

  • Brucella abortus.
  • Brucella suis.
  • Goats and sheep. Brucella malitensis.


  1. Spontaneous abortion or pre-mature birth.
  2. During the later stages of pregnancy, if abortion occurs, there will be retained afterbirth.           The cow may become infertile while bulls have low libido and inflamed testis (orchitis). iv.            A yellowish brown, slimy, odourless discharge from the vulva may occur after abortion.


  1. Use of artificial insemination.
  2. Affected animals should be culled, slaughtered and disposed well.
  • Vaccinating all young animals against the disease. iv. Avoid direct contact with the aborted foetus.
  1. Blood test should be carried out for all breeding animals to detect the infected ones.
  2. Cleanliness should be maintained in the animal’s houses. vii. There is no effective treatment.


Animals affected.

Calves, piglets, lambs and kids.

Causal organism.


Predisposing factors.

  1. Unhygienic conditions in the houses of young ones.
  2. Poor feeding which includes:
  • Feeding calves on cold milk.
  • Lack of colostrum.
  • Feeding at irregular intervals.


  1. White or yellowish diarrhoea in calves.
  2. Faeces of affected animals have a pungent smell.
  • High temperatures/fever. iv. Animal becomes restless.
  1. Loss of appetite/anorexia.
  2. Sunken eyes. vii. Undigested milk and mucus with blood spots in faeces. Faecal matter sticks to the hindquarters.

viii.      Sudden death if no treatment is given. ix.           Recovered animals generally remain weak.


Treatment and control. 

  1. Maintain cleanliness in animals’ houses.
  2. Dampness on the floor of the houses should be avoided.            Fingers must be disinfected if used to train young calves to drink from the bucket. iv.       Calving should be in a clean and disinfected area.
  3. Have separate attendants for infected calves to prevent spread.
  4. When the first symptoms are observed, replace milk feeding with warm water mixed with glucose for a day. 1:1 milk: water ration mixed with glucose for 2 days and normal milk ration on the 4th
  • Calf houses should have a raised floor. viii. Treatment with antibiotics.


Animals affected.

All ruminants 8-18 months old. Cattle, sheep after shearing and goats.

Causal organism.

Clostridium chauvei.

Chauvei septicum .which is spore forming and predominately living in the soil.

Enters the body through contaminated water or through wounds.


  1. Lameness. Becomes severe and the animal is forced to lie down. ii. Affected parts become swollen immediately. (Hind quarters, shoulders and chest.)

iii. Rise in body temperatures. iv. Heavy and fast breathing.

  1. When swollen parts are touched they crackle (fizzing, popping sound).
  2. Animal becomes dull and goes off feed. vii. The animal stops chewing cud.
  • Sudden death occurs.
  1. There is grunting and grinding of teeth.
  2. Bloody froth with a characteristic smell of rancid butter. xi. Blood oozes from the anus and nose of the dead animal. xii.      If the affected muscles are cut, they appear dark.


  1. Treatment using antibiotics e.g. penicillin, oxytetracycline and chlorotetracycline.
  2. Vaccination with Blanthax.          Carcass should be buried deep or burnt completely.


Acute infectious and notifiable zoonotic disease.

Animals affected.

All warm blooded animals; cattle, sheep, goats, man and wild animals.

Causal organism.

Bacillus anthracis.


  • Bites from insects.
  • Grazing in infected pastures. (Faeces of affected animals).
  • Open wounds.
  • Infected roughages, bones and bone meal.

Symptoms (in less severe form)

  1. The animal is swollen on the underside of the belly. Extensive bloating of the stomach after death.
  2. The animal develops fever. iii. Blood stains in faeces and in milk. iv. Swelling of throat in pigs that may cause death due to suffocation.
  3. Tar-like watery blood comes off the orifices e.g. nose, anus and mouth. Blood does not clot easily.
  4. Carcass of an anthrax lack rigor mortis that is stiffness of body after death.


  1. Curative treatment. Large doses of anti-anthrax serum antibiotics e.g. procaine penicillin. ii. Treatment of wounds.
  • The dead animal must be burnt or buried very deep 2M deep and thorns put in the hole before refilling with soil. The area is then fenced to prevent other animals from grazing in that area. Calcium oxide is sprinkled on the carcass to kill any bacteria.
  1. Carcass should never be opened.
  2. Vaccination using Blanthax. vi. Quarantine in case of an outbreak. 8)  

Infectious lung fever.

Animals affected.

Calves, kids, lambs, piglets, poultry.

Causal organism.

S Bacteria or viruses.

E.g. contagious bovine pleuropneumonia is caused by Mycoplasma mycoides.

S Dust and worms in the lungs also cause the disease.


Predisposing factors.

  1. Poor ventilation leading to lack of enough oxygen.
  2. iii. Age. Young animals are more prone to the disease. iv.   Effects of diarrhoea and other illness.


  1. Animals become dull and reluctant to move.
  2. Loss of appetite. iii. Animals become emaciated. iv.          The animals breathes rapidly.
  3. Abnormal lung sounds e.g. hissing, gurgling and bubbling when breathing.
  4. If chest is pressed, the animal starts coughing. vii. Fluctuating body temperatures. viii.   The animal develops a rough hair coat. ix.      Nasal mucous discharge.

 Control and treatment.

  1. Young animals should be kept in warm pens. ii. Proper sanitation should be maintained.  iii.    Affected animals should be isolated for proper nursing in a warm pen. iv.    Early cases should be treated using antibiotics.



  • Foot and mouth disease.
  • Fowl pox. 4)

5) African swine fever.


Notifiable disease and is highly contagious.

Animals affected.

Cattle, sheep, goats, pigs and wild animals that are cloven footed.

Causal organism.

Virus with an incubation period of 3-15 days.


  1. High temperatures.
  2. Starring coat. iii. Discharge in the mouth and nose. iv.          Eyes appear watery.
  3. Diarrhoea and dysentery.
  4. Mucus membrane of the mouth and nose become red, develops wounds or ulcers. vii. The animal becomes emaciated.

viii.      Animals grinding their teeth. ix.         Death in 2-10 days in acute cases or 3 weeks and above in less acute cases.


Vaccination every six months.

Quarantine during an outbreak.

Killing of affected animals.

Nurse animals with disinfectants on wounds. Antibiotics prevent entry of other diseases.


Contagious and infectious disease of poultry. It is a notifiable disease.

Animals affected.


Symptoms are in less acute forms.


  1. Birds have difficulties in breathing. Produce a harsh, grating rasping sound when breathing.
  2. Beaks remain wide open and necks are strained. iii. Birds become dull. iv. Birds stand with eyes closed all the time.
  3. Birds loose appetite.
  4. Nasal discharge which force birds to shake their heads to clear it.
  • Birds walk with staggering motion because the nervous system is affected. Paralysis of wings and legs may occur,
  • Often the birds have their beaks and wings down. ix. Birds produce watery greenish diarrhoea.
  1. Eggs laid have soft shells.


Control and treatment.

  1. No treatment.
  2. During outbreak all birds should be killed and the houses disinfected before bringing new stock. iii.
  3. Quarantine.


Infectious disease of poultry.

Animals affected.

Chicken, turkey, pigeons.

Causal organism.

Avian fox.

Predisposing factors.

Presence of wounds.

Presence of mosquitoes, ticks, lice and other biting insects.


There are 2 types of fowl pox.

S Cutaneous type. S Diptheric type.

              Symptoms of cutaneous fowl pox.

  1. Lesions on the combs and wattles. At first they are small greyish white. Later they turn into a yellowish brown colour and are bigger in size.
  2. Lesions may occur on legs, vent, and feet and under the wings. iii. In severe attack birds lose appetite, become emaciated and eventually die.

Symptoms of Diptheric fowl pox.

S Affects inside of throat and mouth mucous membrane.

  1. In early stages the eyes and nose have a watery liquid discharge.
  2. Loss of appetite. iii. Birds become dull.
  3. Birds are emaciated.

Control and treatment.

  1. All affected birds should be removed and killed. ii. The remaining healthy birds should be vaccinated.


Reported first in Gumboro in East coast of America.

Animals affected.

Chicken, turkey, pigeons and ducks.

Causal organism.

Birna virus.

Affects B-lymphocytes in bursa of fibricus (glands above the vent of birds).

Affects the thymus, spleen and caecal tonsils.

Incubation period is 2-3 days.


  1. The gland above the vent (Bursa) becomes swollen.
  2. Decrease in egg production. iii. Respiratory distress.
  3. Affected birds’ shows low water intake.
  4. Severe immune-suppression making birds more susceptible to the diseases. vi. In hot weather and high humidity mortality rate increases.


  1. Vaccinate healthy birds with attenuated vaccines e.g. PGB98.
  2. Use vitamins especially B12 for fast manufacture of blood.



Highly contagious, infectious and fatal disease of domestic pigs.


Direct contact with reservoir animal.


Infected farm structures e.g. pig pens.

Animals affected.

All breeds of domestic pigs especially female pigs.

Causal organism.

Irido virus. It is highly resistant to putrefication heat and dryness. Survives in chilled carcass for up to six months.

Incubation period is 5-15 days.


  1. Rise in temperatures up to 40-41 degree Celsius.
  2. Loss of appetite. iii. Animals becomes depressed. iv.
  3. Nasal discharge. vi. In serious cases the pigs start to diarrhoea.


  1. Vaccinate animals in case of outbreak.
  2. Impose quarantine. iii. Kill and dispose affected animals as well. iv.     Prevent consumption of pig products from pandemic areas.
  3. Institute double fencing to keep wild animals away.


MILK FEVER. Parturient paresis. 

Animals affected,

  • Cows that have recently calved.
  • Goats and pigs in similar conditions may be affected.


  • Low calcium levels in blood. This leads to increase in magnesium and sugar level.
  • Occurs in high producing cows in first few months of lactation.


  1. Muscular twitching causing the animal to tremble.
  • The animal staggers as it moves. iv. The animal falls down and become unconscious.
  1. The animal lies down on its side and the whole body stiffens.
  2. Body functions such as urination, defecation and milk secretion stop. vii. Sudden death if treatment is not prompt.
  • Stomach contents are drawn into the mouth which later causes lung fever when breathing in.
  1. Complete loss of appetite.

Control and treatment.


Intravenous injection of soluble calcium salt in form of calcium borogluconate 60gms dissolved in 500cc of water that is boiled and then cooled.

Nursing care.

Sick animal should be kept in a comfortable position that is resting on its sternum.

Mechanical removal of urine will speed up recovery.

Do not give the animal medicine orally because of:

  • It will not be able to swallow.
  • The medicine may get into the lungs promoting lung fever thus speeding up death.


  • For cows with past cases of milk fever, partial milking is done for the first 10days.
  • Give high yielding cows’ rations containing phosphorous and calcium. S High doses of vitamin D and parathyroid extraction.



Accumulation of gases as a result of food fermentation in the rumen.

Animals affected.

Attacks ruminants: cattle, sheep, and goats.

Causal organism.

  • Obstruction of the oesophagus due to bulky food particles such as potatoes, carrots and mangoes.
  • Abnormal pressure exerted on the oesophagus by a swelling in the wall of the chest.
  • Caused by an accumulation of gases due to paralysis of the rumen and its entrance. E.g. due to ingestion of poisonous herbs or due to sudden change of feeds especially from soft green forage taken in large amounts.


  1. Left side of abdomen is excessively distended filled with gases that can be felt by pressing with hand.
  2. Death may occur within hours to the much pressure exerted on blood vessels, lungs and heart.

Control and treatment.

Feed ruminants with dry roughage during wet season before grazing on the lush.

Treatment involves the release of accumulated gases through:

Manual means. Exercising the animal and rubbing its abdomen with both hands and making slow prodding movement with fists. Stimulates the rumen movement.

Surgical means. Use of stomach pump, or piercing the abdomen wall using trocar and canula or a sharp knife.

Chemical means.

  • Drenching using suitable oils e.g. turpentine oil mixed with vegetable oil.
  • Administering Epsom salt to clean the reaming rumen content. Given as a drench.
  • Administration of methyl silicone as an injection directly into the rumen. Prevents frothy (bubble) type of bloat by increasing surface tension of the food mass in the rumen.



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