Breed high-yield cows?
Reveal answer
Best cows × bulls from high-yield mothers → select → repeat.
Key words: bulls
6(b) SELECTIVE BREEDING · RECALL
6.11 Selective breeding of animals
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Why is inbreeding harmful?
Reveal answer
More homozygous recessive → genetic disorders.
Key words: recessive
Technique to use one bull's sperm widely?
Reveal answer
Artificial insemination.
Key words: insemination
Welfare issue in breeding?
Reveal answer
Bred features cause health problems.
Key words: health
What is meant by the term inbreeding?
Reveal answer
Breeding closely related individuals.
Key words: inbreeding
What is meant by the term milk yield?
Reveal answer
The volume of milk an animal produces.
Key words: milk yield
What is meant by the term temperament?
Reveal answer
The typical behaviour of an animal, for example docile or aggressive.
Key words: temperament
What is meant by the term artificial insemination?
Reveal answer
Placing collected sperm into a female without mating.
Key words: artificial insemination
Selective breeding in animals: for Dairy cattle, give the desired characteristic and the possible problem.
Reveal answer
Desired characteristic: High milk yield. Possible problem: Possible lameness or udder infection.
Key words: Dairy cattle
Selective breeding in animals: for Broiler chickens, give the desired characteristic and the possible problem.
Reveal answer
Desired characteristic: Rapid growth. Possible problem: Legs may struggle to support body mass.
Key words: Broiler chickens
Selective breeding in animals: for Sheep, give the desired characteristic and the possible problem.
Reveal answer
Desired characteristic: Fine, heavy fleece. Possible problem: Reduced genetic variation.
Key words: Sheep
Selective breeding in animals: for Dogs, give the desired characteristic and the possible problem.
Reveal answer
Desired characteristic: Particular appearance or behaviour. Possible problem: Inherited disorders from inbreeding.
Key words: Dogs
True or false, and why? “Animals adapt during their lives and pass on the change.”
Reveal answer
False. Only inherited alleles are passed on; breeders select individuals that already have the allele.
True or false, and why? “Selective breeding always improves animal health.”
Reveal answer
False. It may cause welfare problems if traits are selected without regard to health.
True or false, and why? “Inbreeding creates harmful alleles.”
Reveal answer
False. It increases the chance of two copies of an existing recessive allele coming together.