06/02/2025 10:03:24
Livestock Production Final Exam
What does the term estrus mean?
In heat
Young female pig
Gilt
Castrated male sheep
Wether
Mature male pig
Boar
Young female cattle
Heifer
Castrated male horse
Gelding
Castrated male cattle
Steer
Cow gestation length
273 days
Sheep gestation length
152 days
Pig gestation length
3 months, 3 weeks, 3 days
Horse gestation length
340 days
What hormone is responsible for females showing "heat"
Estrogen
In what organ does the fetus develop?
Uterus
Artificial insemination
Introduction of semen into the vagina by artificial means
Name 2 species that use AI a great deal.
Cows
Turkeys
Give 2 reasons people would choose to artificially inseminate their livestock.
1. allows females to become pregnant quickly
2. allows lots of females to be impregnated by the same male at the same time.
What is estrous synchronization?
When female livestock come into heat the same time.
What is embryo transfer?
Taking an embryo from one female and planting it into the uterus of another female.
Why do some farmers decide to use embryo transfer in their livestock?
You can get multiple surrogate females pregnant with good breeding stock, allowing
more expensive and better quality calves to be born.
Why would someone want to use sexed semen in cattle breeding?
If one gender is better quality or more expensive, they would get more for calves of
that gender.
What is the union of sperm and ovum called?
Fertilization
1
, 06/02/2025 10:03:24
Heterosis is the same as
Hybrid vigor
Phenotype = Genotype +
Environment
DNA carries the code to produce
Proteins
What is the term for the average age of the parents when their offspring are born?
Generation interval
What is the term for the average superiority of animals selected to be parents
(replacements) over the average of the total group from which they are selected?
Selection differential
Name a sex limited trait.
How much milk a lactating mother produces.
The % of total phenotypic differences that is due to breeding value.
Heritability
What is inbreeding?
Breeding animals that are related
ex: brother-sister, father-daughter, mother-son
Why do people advice against inbreeding?
It keeps diseases and undesirable traits in the family with a high % chance of
showing up in the offspring.
What is crossbreeding?
Mating individuals of different breeds.
What is a reason people want to cross breed?
To produce offspring with the best traits from both breeds.
Give evidence that genetic change is occurring in livestock.
Animals are living longer, have better quality meat and produce more offspring.
Which method of selection involves selecting for only one trait at a time?
Tandem
Which method of selection involves a formula for ranking individuals against all
others by combining several traits and obtaining an overall score?
Selection index
Which method of selection uses cut-off points or levels to eliminate undesirable
animals?
Independent culling level
What is grading up?
Crossing one breed with another enough times that it is considered purebred.
Length of a horse's estrous cycle?
21 days
Length of a cow's estrous cycle?
21 days
Length of a sheep's estrous cycle?
17 days
Length of a pigs estrous cycle?
21 days
Explain the major function of effect of progesterone.
Stimulates the growth of a cushion lining of the uterus where the fertilized egg can
grow.
Explain the major function of the effect of testosterone.
2
Livestock Production Final Exam
What does the term estrus mean?
In heat
Young female pig
Gilt
Castrated male sheep
Wether
Mature male pig
Boar
Young female cattle
Heifer
Castrated male horse
Gelding
Castrated male cattle
Steer
Cow gestation length
273 days
Sheep gestation length
152 days
Pig gestation length
3 months, 3 weeks, 3 days
Horse gestation length
340 days
What hormone is responsible for females showing "heat"
Estrogen
In what organ does the fetus develop?
Uterus
Artificial insemination
Introduction of semen into the vagina by artificial means
Name 2 species that use AI a great deal.
Cows
Turkeys
Give 2 reasons people would choose to artificially inseminate their livestock.
1. allows females to become pregnant quickly
2. allows lots of females to be impregnated by the same male at the same time.
What is estrous synchronization?
When female livestock come into heat the same time.
What is embryo transfer?
Taking an embryo from one female and planting it into the uterus of another female.
Why do some farmers decide to use embryo transfer in their livestock?
You can get multiple surrogate females pregnant with good breeding stock, allowing
more expensive and better quality calves to be born.
Why would someone want to use sexed semen in cattle breeding?
If one gender is better quality or more expensive, they would get more for calves of
that gender.
What is the union of sperm and ovum called?
Fertilization
1
, 06/02/2025 10:03:24
Heterosis is the same as
Hybrid vigor
Phenotype = Genotype +
Environment
DNA carries the code to produce
Proteins
What is the term for the average age of the parents when their offspring are born?
Generation interval
What is the term for the average superiority of animals selected to be parents
(replacements) over the average of the total group from which they are selected?
Selection differential
Name a sex limited trait.
How much milk a lactating mother produces.
The % of total phenotypic differences that is due to breeding value.
Heritability
What is inbreeding?
Breeding animals that are related
ex: brother-sister, father-daughter, mother-son
Why do people advice against inbreeding?
It keeps diseases and undesirable traits in the family with a high % chance of
showing up in the offspring.
What is crossbreeding?
Mating individuals of different breeds.
What is a reason people want to cross breed?
To produce offspring with the best traits from both breeds.
Give evidence that genetic change is occurring in livestock.
Animals are living longer, have better quality meat and produce more offspring.
Which method of selection involves selecting for only one trait at a time?
Tandem
Which method of selection involves a formula for ranking individuals against all
others by combining several traits and obtaining an overall score?
Selection index
Which method of selection uses cut-off points or levels to eliminate undesirable
animals?
Independent culling level
What is grading up?
Crossing one breed with another enough times that it is considered purebred.
Length of a horse's estrous cycle?
21 days
Length of a cow's estrous cycle?
21 days
Length of a sheep's estrous cycle?
17 days
Length of a pigs estrous cycle?
21 days
Explain the major function of effect of progesterone.
Stimulates the growth of a cushion lining of the uterus where the fertilized egg can
grow.
Explain the major function of the effect of testosterone.
2
