Repro: Oestrus Detection & AI

Question 1

Why is oestrus detection performed?

Answer 1

• to time natural mating and/or AI
• to determine the success of mating (non-return to oestrus)
• to determine the onset of puberty
• to determine the start of the breeding period
• to determine if a female is ready for mating
• to indirectly assess animals’ health and nutritional status

Question 2

What are the impacts of poor oestrus detection?

Answer 2

• missed breeding opportunity
  
  • breeding delayed
  • female reduced performance
  • unnecessary veterinary interventions to treat false anoestrus
• inefficient use of feed
  
  • offering a non-pregnant animal the allowance for a pregnant animal
• unintended/unplanned breeding

Question 3

What are the advantages of artificial insemination?

Answer 3

• increases selection intensity (selectively breed best females with chosen sire)
• provide access to otherwise unavailable sires (location, dead)
• limit the spread of sexually transmitted diseases
• introduction of new breeds
• reduces the cost of keeping large/dangerous sires
• allows for out of season breeding
• access to proven sires (from a progeny testing scheme)
• selecting offspring gender (semen can be sexed)

Question 4

What are the disadvantages of artificial insemination?

Answer 4

• can be associated with lower conception rates
• highly dependent on good oestrus detection
• requires skilled technician
• requires industry organisation if done on a large scale
• needs to be used with synchronised oestrus in many farming situations
• may result in the loss of genetic variation (everyone wants the same good sire)
• some males shed viruses in the semen without clinical signs of disease

Question 5

What factors affect the male side of AI?

Answer 5

• fertility of the male and semen quality
• collection technique
• use of semen extenders
• chilling or cryopreservation

Question 6

What factors affect the female side of AI?

Answer 6

• anatomy of the species
• oestrus detection
• timing of insemination relative to ovulation
• conception rates

Question 7

When should insemination be done for optimal results?

Answer 7

12-24 hours before ovulation

Question 8

What causes true anoestrus (TA)?

Answer 8

• pregnancy
• post-partum period
• arrest of ovarian activity
• other endocrine disturbance (luteal or follicular cysts)

Question 9

What can cause non-detected oestrus?

Answer 9

• true anoestrus (TA) and detection failure

Question 10

How can you differentiate true anoestrus and non-detected oestrus?

Answer 10

• physical examination of cows
• history
• herd records

Question 11

What are the causes of detection failure?

Answer 11

• lack of training
• insufficient personnel
• lack of time/frequency
• surface
• other conditions (laminitis, mastitis)
• weekend syndrome (not paying attention)

Question 12

What are the consequences of detection failure?

Answer 12

• low submission rates
• low conception rates
• low pregnancy rates
• late conception
• increased culling rate

Question 13

Poor oestrus detection in a dairy cattle can be due to…

Answer 13

• errors in diagnosis
  
  • cow recorded in oestrus when she is not
  • results in insemination at wrong time and low conception rates
• errors of omission
  
  • oestrus cow not detected, missed mating opportunity
  • results in a later insemination and thus later calving date
• errors of identification
  
  • oestrus cow is identified but the wrong number is recorded, thus wrong cow inseminated
  • results in lower conception rates

Question 14

Where are cattle artificially inseminated?

Answer 14

intrauterine deposition

Question 15

Where are small ruminants artificially inseminated?

Answer 15

vaginal (maybe intracervical)

Question 16

Where are sows artificially inseminated?

Answer 16

intracervical deposition

Question 17

Where are mares artificially inseminated?

Answer 17

intrauterine deposition