NDDB veterinary and executive posts Livestock & Poultry Breeding: practice questions

Question 1 · medium

A pig breeding nucleus wants to improve lean meat percentage measured on the carcass. Candidate boars cannot be slaughtered. The appropriate source of information is:

1. The boar's own carcass record
2. The boar's own weaning weight only
3. Carcass records of full sibs slaughtered at a test station, in an index or BLUP
4. The dam's litter size and weaning weight records across all her previous parities

Question 2 · medium

Which of the following is New Zealand's national total-merit index for dairy cattle?

1. Breeding Worth (BW)
2. Net Merit dollars (NM$)
3. Profitable Lifetime Index (PLI)
4. Nordic Total Merit (NTM)

Question 3 · medium

In a dairy herd, milk yield falls by about 20 kg per lactation for each 1% increase in inbreeding. A heifer is the offspring of a half-sib mating (F = 0.125). Her expected loss in lactation yield due to inbreeding is:

1. 2.5 kg
2. 500 kg
3. 125 kg
4. 250 kg

Question 4 · hard

An FAO review of Bos taurus × Bos indicus crossbreeding for milk in the tropics (Cunningham and Syrstad, 1987) found that animals produced by mating crossbreds among themselves (F2 and later) usually:

1. Performed worse than the F1, partly because of loss of heterosis
2. Performed better than the F1 because of recombination
3. Performed the same as the F1
4. Performed better than purebred exotic cattle in every environment

Question 5 · medium

In a three-tier breeding pyramid, the genetic merit of commercial animals typically lags behind that of the nucleus by about:

1. Ten generations' worth of genetic gain
2. Two generations' worth of genetic gain
3. Nothing, if AI is used
4. Half a generation's gain

Question 6 · medium

In pastoral areas where there is little recording and no AI, the approach that organises selection of breeding males within villages, with farmers setting the breeding objective, is called:

1. A MOET nucleus scheme
2. A closed commercial pyramid
3. Genomic selection
4. A community-based breeding programme

Question 7 · hard

A state wants to raise milk production from its Sahiwal cattle in the breed's native breeding tract without threatening the breed. Consistent with India's breeding policy, the appropriate strategy is:

1. Crossbreeding Sahiwal cows with Holstein-Friesian bulls throughout the whole native breeding tract
2. Grading up Sahiwal to Jersey
3. Selective breeding within Sahiwal, using progeny-tested or pedigree-selected Sahiwal bulls
4. Replacing Sahiwal with non-descript cattle

Question 8 · medium

For which kind of trait does genomic selection bring the greatest relative improvement over traditional selection?

1. Low-heritability, sex-limited or late-recorded traits such as female fertility and longevity
2. Highly heritable traits recorded early on both sexes, such as growth rate and yearling body weight
3. Traits controlled by a single major gene with a known test
4. Traits with no genetic variation

Question 9 · medium

A breed is to be restored from a gene bank that holds only frozen semen. Females of another breed are inseminated, then their daughters and granddaughters are backcrossed with the stored semen. How many generations of crossing are needed before offspring first carry more than 90% of the original breed's genes?

1. Four (93.75%)
2. Two (75%)
3. Three (87.5%)
4. Five (96.9%)

Question 10 · medium

In a laboratory mouse facility, the foundation colony of an inbred strain should be maintained by:

1. Strict brother × sister mating with full pedigree records, from which expansion colonies are derived
2. Random mating of many unrelated breeders
3. Rotational mating between groups
4. Crossing with another strain every generation to prevent inbreeding depression in the foundation colony