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ICAR AIEEA Livestock & Poultry Breeding: practice questions

ICAR AIEEA (PG): Master's entrance, Veterinary Science and Animal Sciences · India · NTA for ICAR

Original practice questions written to the published syllabus · not past papers
10worked here, free
59written to this exam in this subject
12syllabus units

What this subject covers

Selection and mating systems that improve herds and flocks, sire evaluation, genomic selection and the conservation of animal genetic resources.

In the exams: ICAR AICE-JRF core group 05; ICAR AIEEA-PG 14 (AGB); EGEL Plus reproduction and genetics 15

What ICAR AIEEA asks from it

ICAR AIEEA (PG), Code 14 Animal Sciences (AGB)

Definitions and formulae: selection differential and intensity, generation interval, methods of selection, crossbreeding systems, heterosis, sire evaluation methods, Indian composite breeds and breeding policy.

Where the 59 questions fall

How our questions for ICAR AIEEA spread across the units of Livestock & Poultry Breeding. Difficulty: 26 easy, 30 medium, 3 hard.

Outbreeding and crossbreeding8
Response to selection6
Inbreeding6
Heterosis6
Laboratory animal breeding6
Breeding strategies and national breeding policy5
Sire evaluation and progeny testing5
Conservation of animal genetic resources5
Selection index4
Methods of selection3
Genomic selection3
Selection experiments2

10 practice questions, worked

Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.

1 · Response to selection · medium

In a pig herd, mean body weight at 180 days is 90 kg. The boars and gilts selected as parents (mass selection in both sexes) average 102 kg at the same age. Heritability is 0.25. The expected response in the next generation is:

  1. 3.0 kg
  2. 25.5 kg
  3. 12.0 kg
  4. 22.5 kg
Answer and working

A. 3.0 kg

S = 102 − 90 = 12 kg. R = h²S = 0.25 × 12 = 3.0 kg. Multiplying h² by the selected mean (25.5) or by the herd mean (22.5) uses the wrong basis; 12 kg is the selection differential, not the response.

2 · Selection index · easy

The selection index was first applied to animal breeding by:

  1. H. Fairfield Smith (1936)
  2. C.R. Henderson (1973)
  3. Sewall Wright (1921)
  4. L.N. Hazel (1943)
Answer and working

D. L.N. Hazel (1943)

Smith (1936) introduced the discriminant function for plant selection; Hazel (1943) developed the index for animals using genetic and phenotypic parameters. Henderson developed BLUP; Wright developed path coefficients and the inbreeding coefficient.

3 · Inbreeding · medium

Two half sibs are mated. Their common parent has an inbreeding coefficient of 0.2. The inbreeding coefficient of their offspring is:

  1. 0.125
  2. 0.150
  3. 0.325
  4. 0.25
Answer and working

B. 0.150

F = (½)^(1+1+1) × (1 + FA) = 0.125 × 1.2 = 0.150. 0.125 ignores the ancestor's own inbreeding; adding 0.2 directly (0.325) is not how the formula works; 0.25 is the full-sib value.

4 · Outbreeding and crossbreeding · easy

The mule is produced by mating:

  1. A male donkey (jack) with a female horse (mare)
  2. A stallion with a female donkey (jenny)
  3. A male donkey with a female zebra
  4. A stallion with a mare of a draught breed
Answer and working

A. A male donkey (jack) with a female horse (mare)

Jack × mare gives the mule; stallion × jenny gives the hinny. Both are almost always sterile because horse and donkey chromosome numbers differ.

5 · Sire evaluation and progeny testing · easy

The contemporary comparison method of sire evaluation was introduced in the United Kingdom by:

  1. Henderson (1973)
  2. Hazel (1943)
  3. Lush (1937)
  4. Robertson and Rendel (1954)
Answer and working

D. Robertson and Rendel (1954)

Robertson and Rendel compared each daughter with contemporary heifers by other sires in the same herd and season. Henderson developed BLUP; Hazel the selection index; Lush wrote the foundational text Animal Breeding Plans.

6 · Sire evaluation and progeny testing · medium

Compared with lactation models, test-day models in dairy sire and cow evaluation:

  1. Use only the peak yield of each cow
  2. Ignore herd effects
  3. Use individual test-day milk records and account for the environment of each test day
  4. Can be used only for bulls with at least 100 daughters that have completed full lactations
Answer and working

C. Use individual test-day milk records and account for the environment of each test day

Test-day models analyse each recording separately, allowing for the specific herd-test-date environment and making use of incomplete lactations, which improves accuracy. They include herd effects.

7 · Conservation of animal genetic resources · easy

N'Dama cattle of West Africa are an important genetic resource mainly because of their:

  1. Very high milk yield
  2. Trypanotolerance
  3. Double muscling (myostatin)
  4. Natural polledness
Answer and working

B. Trypanotolerance

N'Dama and West African Shorthorn cattle tolerate trypanosome infection in tsetse areas, an adaptation that is hard to recreate and a key reason for conserving them.

8 · Laboratory animal breeding · easy

A mouse strain is considered inbred after at least how many consecutive generations of brother × sister mating?

  1. 5
  2. 10
  3. 20
  4. 50
Answer and working

C. 20

By convention, an inbred strain requires at least 20 consecutive generations of brother × sister (or parent × offspring) mating, giving F of about 0.986.

9 · Laboratory animal breeding · medium

Starting from a non-inbred base, three consecutive generations of full-sib mating give an inbreeding coefficient of:

  1. 0.750
  2. 0.375
  3. 0.125
  4. 0.500
Answer and working

D. 0.500

Using Ft = ¼(1 + 2Ft−1 + Ft−2): 0.25, 0.375, then ¼(1 + 0.75 + 0.25) = 0.500. 0.375 is the second generation; adding 0.25 per generation (0.75) overstates it; 0.125 is half-sib mating.

10 · Laboratory animal breeding · medium

F1 hybrid mice produced by crossing two inbred strains are:

  1. Genetically variable like outbred stocks
  2. Homozygous at all loci
  3. Genetically uniform and vigorous, but they do not breed true
  4. Identical to either parental strain
Answer and working

C. Genetically uniform and vigorous, but they do not breed true

All F1 animals receive one set of chromosomes from each inbred parent, so they are identical to each other and heterozygous wherever the strains differ, showing heterosis. Mating F1 × F1 produces a segregating F2.

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Read the subject

Livestock & Poultry BreedingThe full study manual, free ICAR AIEEAFormat, sections and how it has changed

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Livestock & Poultry Breeding for other exams

ASRB NET and ARS / SMS / STO · IndiaICAR AICE-JRF/SRF · India

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