Animals

Animal reproduction

Animal reproduction on a farm is the oestrus cycle, mating, pregnancy and birth, managed so young arrive when feed is there.

CAPS

Grade 11 · Agricultural Sciences · Animals

Agricultural Sciences splits animals from plants, soil and management.

The papers
Paper 1 is animal nutrition, animal production, reproduction and protection. Paper 2 is soil science, plant studies, and agricultural management. Each paper is 150 marks.
How to write it
Use the farming term, then the reason: a deficient mineral, a symptom, a management practice, and why it changes the yield or the health of the animal. A list with no cause does not explain.
How a marker reads it
A common mix-up is to use one pregnancy length for every species, or to think artificial insemination shortens pregnancy.

Data-response questions want you to read the table first. A general paragraph about farming that ignores the numbers scores as if you did not see them.

Diagram

Worked theory

Worked theory. A beef herd. The farmer watches for standing heat, brings the bull or the inseminator, and records the date. Nine months later, calves should fall in the months when the veld is green, not in the driest weeks. Miss the oestrus and the cow waits another cycle, and the calf arrives late, onto poor grass. Artificial insemination does not change pregnancy length. It changes which bull is the father, including a bull that never came to the farm. The record of the date is what makes the feed match the birth.

More worked examples

A missed heat in November
A cow on heat on 1 November is served that day. Pregnancy is about 280 days, so the calf arrives in early August, onto late-winter veld that is still poor. Miss that heat and the next one is three weeks later. The calf then arrives in September. Serve her in January instead, on purpose, and the calf arrives in October, when the grass has started. The bull did not change the 280 days. The date of service did.
One straw of semen
A good bull’s semen is stored in straws and used on many cows. The farmer does not need that bull in the camp, and a cow that is already pregnant is not inseminated. Heat still has to be detected, because the straw only works if she is in oestrus. Missing the day wastes the straw and slips the calving date by three weeks, the length of the cycle. The straw did not cancel the cycle. It replaced the bull.

In ordinary words

Oestrus is the time the female will accept the male. The length of the cycle and of pregnancy is typical for the species: a cow’s pregnancy is about nine months, a sow’s about three months, three weeks and three days, a ewe’s about five months. Signs of oestrus, such as restlessness and standing to be mounted, tell the farmer when to mate or to use artificial insemination. The sire and the dam both contribute genes. A good season of births is a plan, not luck.

In South Africa

A marked calving date on a herd card is this theory in the farmer’s pocket.

Part 1 / 4

What it is

Animal reproduction on a farm is the oestrus cycle, mating, pregnancy and birth, managed so young arrive when feed is there.

Animal breeding and the oestrus cycle — Diagram

More worked examples

Board walkthroughs on this topic. Open one, copy the working, then try the next.

Example 1 / 20

A cow's gestation is about 283 days. If she is inseminated on 1 March, roughly when will she calve?

4. Step-by-step working

01
Add
March (after the 1st) 30 + Apr 30 + May 31 + Jun 30 + Jul 31 + Aug 31 + Sep 30 + Oct 31 + Nov 30 = 274 days to 30 November.
02
Subtract
283 − 274 = 9 days into December → 9 December.

How we got there

Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

Explain in another language · 11

1. What is the question asking?

Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A cow's gestation is about 283 days. If she is inseminated on 1 March, roughly when will she calve?

In other words — as if you have never seen this before

If you have never seen this before: Count the days left in each month. We will name a method in words, write the formula with no numbers, then substitute one line at a time.

2. What do we already know?

283 days from 1 March.

3. Which method — and why this one?

Count the days left in each month.

4. Step-by-step working

01 / 05
Add
March (after the 1st) 30 + Apr 30 + May 31 + Jun 30 + Jul 31 + Aug 31 + Sep 30 + Oct 31 + Nov 30 = 274 days to 30 November.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
02 / 05
Subtract
283 − 274 = 9 days into December → 9 December.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
03 / 05
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
04 / 05
Step F — Box the answer with its unit
About 9 December.
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
05 / 05
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

5. The answer

About 9 December.

Copy onto your answer sheet — in this order

Answer: About 9 December.

6. Check it like a marker

Gestation: sheep ≈ 150 days, pig ≈ 114 days.

7. A trap first-timers fall into

First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

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