Livestock Products
Senior 1 · Agriculture
Livestock Products
Lesson 1 of 4
22 min
Walk through a craft market in Kigali and you will find cattle everywhere, even though there is not a cow in sight: leather sandals and bags, drums covered with cowhide, combs and ornaments carved from horn, and black-and-white imigongo panels whose raised patterns are moulded from cow dung. At the nearest shop there is milk, yoghurt and butter; at the butcher's, beef.
A cow is kept mainly for milk or meat, but almost every part of the animal, living or slaughtered, has a use. A farmer or cooperative that knows these uses, and sells or uses every one, earns far more from the same animals. This lesson sorts cattle outputs into products and by-products and explains what each is used for. (How to keep these products from spoiling is studied in S2.)
Whether something is a main product or a by-product depends on why the animal is kept. On a dairy farm the hide of a culled cow is a by-product; nobody keeps a cow for its hide.
A dairy cooperative near Nyabihu lists what it gets from its cows in a year: milk, cheese, calves, dung, urine, a hide from a cow that was culled and slaughtered, and bones and blood from that slaughter. Sort them.
| Product | What it is and why it matters |
|---|---|
| Milk | A nearly complete food. Cow's milk is roughly 87% water, with the rest made up of fat (butterfat), protein, milk sugar (lactose), minerals such as calcium, and vitamins. In Rwanda the Girinka programme and school milk schemes have made milk a key food for children. Most farm milk is taken to a milk collection centre, where it is tested and cooled. |
| Beef | Meat from mature cattle; veal is meat from young calves. Rich in protein and iron. |
| Offal | Edible internal organs: liver, kidneys, heart, tongue and tripe (stomach). Sold more cheaply than beef but highly nutritious. |
| By-product | Uses |
|---|---|
| Hide (skin of a large animal) | Tanned into leather for shoes, belts, bags, furniture; traditional drums (ingoma) are covered with cowhide |
| Dung | Farmyard manure and compost; fuel for a biogas digester; the raw material of imigongo art, moulded from a mixture of cow dung and ash; plastering floors in some rural homes |
| Urine | Liquid fertiliser, rich in nitrogen and potassium |
| Blood | Dried and ground into blood meal, a protein feed and a nitrogen fertiliser |
| Bones | Ground into bone meal, a source of calcium and phosphorus in pig and poultry feed and a slow-release fertiliser; also used to make gelatin and glue |
| Horns and hooves | Carved into combs, buttons, cups and ornaments; ground into horn and hoof meal (fertiliser) |
| Fat (tallow) | Soap and candles |
When an animal is slaughtered, the head, hide, feet, blood and internal organs are removed. What remains is the carcass. The dressing percentage (also called the killing-out percentage) tells you how much of the live animal becomes carcass:
Dressing percentage = carcass weight ÷ live weight × 100
For cattle it is commonly between about 50% and 70%, depending on breed, fatness and how full the gut was.
Worked example
A bull weighing 360 kg live gives a carcass of 198 kg.
Tip
Memory hook: "Main is why you keep it; by comes by the way." The main product is the reason the animal is kept; a by-product comes along with it.
Exam technique: when asked for "uses of a by-product", be specific: "bones are made into bone meal, which supplies calcium and phosphorus in animal feed" earns more than "bones are used for feed".
Distinguish between a main product and a by-product, using a beef farm as your example.
Solution: The main product is the output the animal is kept for: on a beef farm, meat. A by-product is a secondary output obtained along the way: for example the hide, bones, blood and dung.
Give three uses of cow dung in Rwanda.
Solution: Any three of: farmyard manure or compost for crops; fuel for a biogas digester; the raw material of imigongo art; plastering floors.
Name two value-added products made from milk and say why a farmer might make them.
Solution: For example yoghurt (ikivuguto), butter, ghee or cheese. They keep longer than fresh milk and sell for more per litre of milk used.
A steer weighing 420 kg live gives a carcass of 231 kg. Calculate its dressing percentage.
Solution: 231 ÷ 420 × 100 = 55%.
What is blood meal, and what is it used for?
Solution: Blood collected at slaughter, dried and ground into a powder. It is used as a protein-rich ingredient in animal feed and as a nitrogen fertiliser.
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.
