Ruminants
Senior 2 · Agriculture
Ruminants
Lesson 4 of 5
25 min
Let's begin
Regular disease epidemics, with too few veterinary services, are one of the main reasons why Rwandan livestock produce less than they could. One case of East Coast fever can kill an exotic cow worth hundreds of thousands of francs in less than a month. An outbreak of foot-and-mouth disease can close a whole district's cattle markets.
A farmer does not have to be a veterinarian, but must recognise the signs of the common diseases early, know how they spread, and know how to prevent them. That is what this lesson teaches.
| Healthy animal | Sick animal |
|---|---|
| Alert, stays with the herd, eats and chews the cud | Dull, stands apart, stops eating or stops chewing the cud |
| Smooth, shiny coat | Rough, dull coat; hair standing up |
| Clear eyes, moist nose without discharge | Discharge from eyes or nose; pale or yellow eyelids |
| Normal dung and urine | Diarrhoea, blood in dung or urine, or no dung |
| Normal temperature (a cow about 38.5 °C) | Fever; fast or difficult breathing; sudden drop in milk |
Diseases are grouped by their cause: viruses (foot-and-mouth disease, lumpy skin disease, PPR, Rift Valley fever), bacteria (anthrax, brucellosis, mastitis, foot rot), protozoa (East Coast fever), parasites (ticks, worms, mites), and nutritional or management causes (bloat, mineral deficiency). A disease that can pass from animals to people is called a zoonosis.
| Disease | Animals | Cause and spread | Main signs | Prevention and control |
|---|---|---|---|---|
| East Coast fever (theileriosis) | Cattle, especially exotic breeds | Protozoan Theileria parva, carried by the brown ear tick | High fever; swollen lymph nodes (first near the ear); difficult breathing; frothy nasal discharge; death within weeks | Tick control by spraying or dipping with acaricide; treatment by a vet with buparvaquone; vaccination where available |
| Foot-and-mouth disease (FMD) | Cattle, goats, sheep, pigs | Virus; spreads by contact, air, and contaminated vehicles, tools and feed | Fever, then blisters in the mouth and near the hooves; heavy drooling; lameness; sharp fall in milk | Vaccination; quarantine and a ban on animal movement during outbreaks; disinfection |
| Lumpy skin disease | Cattle | Virus spread by biting insects | Fever; firm, round lumps all over the skin | Vaccination; control of biting flies |
| Anthrax (zoonosis) | Cattle, goats, sheep | Bacterium whose spores survive in soil for many years | Sudden death; dark, tarry blood that does not clot oozing from nose, mouth and anus | Yearly vaccination; never open or eat the carcass; report to the vet; bury deep or burn |
| Brucellosis (zoonosis) | Cattle, goats, sheep | Bacterium; spreads through aborted foetuses, afterbirth and raw milk | Abortion late in pregnancy; retained afterbirth; poor fertility | Vaccinate young females; test and remove infected animals; boil or pasteurise milk |
| Mastitis | Cows, does, ewes | Bacteria entering the udder through the teat canal; dirty milking and bedding | Hot, swollen, painful udder; clots, blood or watery milk | Clean, dry bedding; clean milking; teat dipping; treatment by a vet |
| Peste des petits ruminants (PPR, "goat plague") | Goats and sheep | Virus; spreads by close contact | Fever; discharge from eyes and nose; mouth sores; diarrhoea; pneumonia. Up to 80–100% of a flock may die in severe outbreaks | Vaccination; quarantine new animals |
| Worms (e.g. the barber's pole worm) | Especially goats and sheep | Worm eggs in dung hatch on wet pasture and are swallowed with grass | Pale eyelids and gums (anaemia); swelling under the jaw; weight loss; diarrhoea | Regular deworming; rotational grazing; raised slatted floors |
| Foot rot | Sheep and goats | Bacteria in wet, muddy conditions | Lameness; foul-smelling rotten hoof | Dry housing; hoof trimming; footbath with copper or zinc sulphate |
| Bloat | Cattle, goats, sheep | Nutritional: gas trapped in the rumen after eating lush, wet legumes or young grass | Swollen left side; distress; difficult breathing | Wilt legumes before feeding; give hay first; call a vet at once |
A Friesian cow in Rubavu, bought three weeks ago from a farm with many ticks, has a fever, has stopped eating, and the lymph node in front of her shoulder is swollen. Her breathing is fast and there is froth at her nose.
A dewormer label says: 1 mL per 10 kg body weight. A goat weighs 35 kg.
Dose = 35 ÷ 10 × 1 mL = 3.5 mL. Always weigh or estimate the weight carefully: too small a dose leaves worms alive and helps them become resistant to the drug.
Tip
Memory hook: "Ticks bring Theileria": East Coast fever is the tick disease. "Boil milk against Brucellosis." "Anthrax: Always leave the carcass closed."
Exam technique: for a disease question, organise your answer under five headings: cause, animals affected, signs, spread, control. Examiners award marks under each.
Name the cause and the vector of East Coast fever.
Solution: Cause: the protozoan Theileria parva. Vector: the brown ear tick (Rhipicephalus appendiculatus).
A goat found dead has dark blood oozing from its nose that does not clot. What should the farmer suspect, and what must he NOT do?
Solution: Anthrax. He must not open, skin or eat the carcass, because this releases spores that infect people and contaminate the soil for years. He should call the vet and have the carcass buried deep or burned.
Why does brucellosis matter to a family that drinks raw milk?
Solution: Brucellosis is a zoonosis: the bacteria pass to people through raw milk and cause long, repeated fevers. Boiling or pasteurising milk kills them.
A dewormer is dosed at 1 mL per 10 kg. A farmer has 12 goats averaging 30 kg. How much dewormer does he need in total?
Solution: Dose per goat = 30 ÷ 10 = 3 mL. Total = 12 × 3 = 36 mL.
Several sheep are lame, and their hooves smell rotten after a very wet month. Suggest the disease and two control measures.
Solution: Foot rot. Control: move the sheep to dry housing, trim the hooves, and walk them through a footbath of copper or zinc sulphate.
Summary
Sources and credits
The Rwandan examples, worked examples and practice questions are written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
