6. oestrus sync

Question 1

define synchronization of oestrus

Answer 1

A management tool to bring females into oestrus at the same time

Question 2

list 5 advantages of synchronization of oestrus

Answer 2

• Reduces time spent in heat detection
• maximizes the use of artificial insemination
• improves management
• shortens the breeding season
• having a number of females in oestrus at the same time during a short space of time

Question 3

list 4 disadvantages of sync of oestrus

Answer 3

• expensive
• good management practices are essential
• low conception rates where progestagens
• labour intensive

Question 4

list the requirements of oestrus sync

Answer 4

• normal fertility
• method used needs to be effective
• method must be safe
• must have a beneficial effect on cost

Question 5

list the types of oestrus syncs and examples of each

Answer 5

1) natural methods:
a) male effect
b) photoperiod

2) hormonal methods:
a) luteolytic drugs:(PGF2a) shorten life of CL
b) progesterone and its analogues: suppress follicular development

Question 6

list the 4 sync methods in cows

Answer 6

• prostaglandin
• progestin
• ovulation sync
• managed breeding

Question 7

explain the prostaglandin method

Answer 7

single PGF2a injection during day 5-17 of the estrus cycle

regression of CL

return to estrus in 32-72 hours

cows between days 0-5 and 17-21 do not respond to injections since they have no functioning CLs

Question 8

give 5 factors that play a role in successful synchronization of cows

Answer 8

• selection of fertile cows
• know pregnancy status
• skill of inseminator
• flush feeding of animals before insemination
• sufficient semen