Animals - Evaluate management techniques (repro)

Question 1

Evaluate ‘Artificial insemination’ - description and pros/cons + judgement

Answer 1

A.I. - the act of using instruments to deposit semen in the female reproductive tract with the aim of achieving pregnancy

Pros:
- A genetically superior bull can spread his favourable characteristics over far more cows than if natural matings were used (1000-2000 cows compared to about 100 for natural mating) resulting ina genetically superior (e.g. faster growth rate) herd in a shorter time. Farmers may be able to sell animals earlier, allowing a faster return on investment.

• improvement of genotypes of offspring (e.g. better weight gain)
• Eradication or prevention of sexually transmitted disease
• Introduction of new bloodlines from overseas

Cons:

• shrinking of the gene pool = increases the likelihood of recessive lethal or deleterious alleles being expressed.
• requires a certain level of expertise from the farmer - must know how to inseminate and detect when animals are on oestrus
• Expensive: semen from the best bulls can cost hundreds of dollars

Judgement:
- good

Question 2

Evaluate ‘Multiple ovulation’ - description and pros/cons + judgement

Answer 2

Description - crossing animals with breeds that naturally have a high rate of ovulation (e.g. Wensleydale breed in sheep)

Pros:
- Increasing the ovulation rate increases the number of offspring a single female can produce in her lifetime. This would be used in conjunction with embryo transfer.

• Increasing the ovulation rate increases the likelihood of more than one offspring

Cons:
- Increasing the ovulation rate often requires extra labour (e.g. treating animals with gonadotropins)and extra costs (e.g. hormone treat more, more feed required to support additional offspring)
- high variation in the number of eggs released by the donor female due to variables such as animal age, breed and nutrition.

Judgement:
- Increasing the ovulation rate in females should result in an increase in the number ofoffspring produced in a production cycle, which would lead to farmers having an increase in the number of animals available for sale, increasing profit margins

Question 3

Evaluate ‘Flushing’ - description and pros/cons + judgement

Answer 3

Description - given more food before and after birth to increase body weight and condition -increasing fertility.

Advantages:
- Increased chances that an animal will become pregnant.
- increases survival of off-spring
- retains health of mother

Disadvantages:
- extra costs (e.g. feeding more food during flushing)
- requires the farmer to have a level of knowledge/ expertise to manage animals

Judgement: Increased ovulation rate. = increased off-spring