Animal Production: Nutrition, Genetics, Health and Welfare
Core concepts
Animal production questions reward a systems view. Understand the ruminant digestive system and why rumen microbes allow cattle and sheep to use fibrous pasture, contrasted with the monogastric digestion of pigs and poultry. Know the components of a ration: energy, protein, fibre, minerals, vitamins and water, and the meaning of a balanced ration. Understand digestibility, metabolisable energy, protein quality and the role of supplements such as urea or grain in correcting pasture deficiencies.
Genetics and breeding are central: heritability, selection, crossbreeding and hybrid vigour, estimated breeding values and the trade-off between production traits and fitness traits. Animal health requires knowledge of infectious versus non-infectious disease, vaccination, quarantine, biosecurity, parasites and their life cycles, and the principle of responsible antimicrobial use. Welfare is assessed against the five domains: nutrition, environment, health, behaviour and mental state.
Traps to watch
- Confusing a maintenance ration with a production ration; only energy above maintenance supports growth, milk or reproduction.
- Recommending antibiotics for a viral or management problem.
- Ignoring genotype-by-environment interaction: a high-performance breed may fail on poor pasture.
- Treating welfare as only the absence of disease; behaviour and mental state count.
Worked example
Rule of thumb: a ruminant on dry summer pasture is usually short of energy and protein, not minerals. If body condition score falls below the target, supplement energy first and check protein, because rumen microbes need both to digest fibre. Record the change and re-score in two to three weeks.
Exam technique
Answer evaluation questions with a benefit-cost-risk structure: what improves, what it costs, and what could go wrong.