Agricultural Science (AS)·Animal science · NSSCAS 4.3
Reproduction in farm animals & reproductive rates
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Two neighbours near Otjiwarongo each run eighty breeding cows on the same veld, under the same rain. One weans seventy-two strong calves to sell; the other weans only forty. Where did the missing calves go? In this lesson we follow a calf from the very first sex cells, through a well-cared-for pregnancy, past the diseases and problems that steal calves, and finally learn to score a whole herd with conception, calving, weaning and mortality percentages.
What you'll learn in this lesson
By the end you should be able to (NSSCAS Agricultural Science (AS) 4.3):
- Describe gametogenesis — spermatogenesis in the bull and oogenesis in the cow — as the formation of gametes
- Describe the secondary sexual characteristics of mature cattle and how they are used to tell bull from cow
- Assess the needs and requirements for caring for and handling pregnant animals (nutrition, gentle handling, separation, vaccination, shelter, avoiding stress)
- Discuss the factors causing infertility in male and female farm animals
- Discuss the impact of venereal diseases such as trichomoniasis, vibriosis and brucellosis on animal production
- Explain how artificial insemination is used in breeding and disease control
- Calculate conception, calving, farrowing, kidding and weaning percentages
- Calculate the mortality rate of a herd or flock and interpret the results
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Miss Elina and Mike talk through the whole topic — with the figure and working drawn live.