E
ENameLearner

Animals

Animal reproduction

Animal reproduction at Grade 12 is breeding: choosing parents so the next generation is more of what the farm sells.

CAPS

Grade 12 · 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 select on a trait that was feed, not genes, or to breed a sire to his daughters without a reason.

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.

RL

Diagram

Worked theory

Worked theory. Two bulls. One is heavy because he grew in a feedlot. One is heavy on the same veld as the herd. The second bull’s daughters are the fair test. If they grow well on that veld, the weight was heritable in the place the herd actually lives. Keeping a bull’s daughters as his next mates raises the chance of hidden defects showing. Crossing a hardy indigenous breed with a heavier exotic breed can give calves that grow fast and still walk the farm. The worked theory is the parent you can defend with a record.

More worked examples

  • Two bulls, one camp

    Bull A is heavy off a feedlot ration. Bull B is heavy on the same veld as the cows. Bull A’s daughters, put back on that veld, grow no better than the herd. Bull B’s daughters do. The extra kilograms on A were feed, and feed is not inherited. Using A as a sire because he looked bigger at the sale is a selection on the wrong cause. The scale on the camp, not the sale photo, is the record that matters.

  • A broken horn is not inherited

    A cow with a high milk record is worth selecting. A cow with a broken horn is not, unless her records are also good, because the horn broke in a gate and breakage is not passed on. Milk yield is partly heritable, so her daughters tend to milk more, not as a promise to each one but as a tendency. Selecting on the horn changes nothing in the next generation. Selecting on the milk record does.

In ordinary words

Heritability is how much of a trait is passed on, rather than caused by feed or weather. Selecting a bull because he is heavy works only for the share of his weight that is genetic. A cow thin from drought is not genetically small. Inbreeding concentrates genes, good and bad. Crossbreeding mixes breeds and often gives a vigorous first cross. Records of birth dates, weights and parents are what make selection possible. Memory is not a herd book.

In South Africa

A herd book with weights, not a memory of which animal looked big, is the tool.

Part 1 / 4

What it is

Animal reproduction at Grade 12 is breeding: choosing parents so the next generation is more of what the farm sells.

Diagram

More worked examples

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

Example 1 / 20

Explain the role of FSH, LH, oestrogen and progesterone in the cow's oestrous cycle.

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: Explain the role of FSH, LH, oestrogen and progesterone in the cow's oestrous cycle.

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

If you have never seen this before: Follicle → ovulation → corpus luteum. 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?

Reproductive hormones.

3. Which method — and why this one?

Follicle → ovulation → corpus luteum.

4. Step-by-step working

  1. 01 / 07

    Step A — Read the question twice

    Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

    Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

  2. 02 / 07

    Step B — Write the given in a column

    Reproductive hormones.

    Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

  3. 03 / 07

    Step C — Name the method in words

    Follicle → ovulation → corpus luteum.

    Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

  4. 04 / 07

    Explain

    FSH: follicle growth; oestrogen: heat signs; LH: ovulation, corpus luteum; progesterone: maintains pregnancy.

    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.

  5. 05 / 07

    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.

  6. 06 / 07

    Step F — Box the answer with its unit

    FSH → follicle; oestrogen → heat; LH → ovulation; progesterone → pregnancy.

    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.

  7. 07 / 07

    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

FSH → follicle; oestrogen → heat; LH → ovulation; progesterone → pregnancy.

Copy onto your answer sheet — in this order

Answer: FSH → follicle; oestrogen → heat; LH → ovulation; progesterone → pregnancy.

6. Check it like a marker

Prostaglandin breaks down the corpus luteum.

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…”

Share on WhatsApp

Next lesson →

Agricultural genetics

Agricultural Sciences

Take topic quiz

Ntsako · fx-991ZA PLUS. Tap to calculate.