Fertility problems (Yr 4)

Question 1

what are the three possible fates of the first dominant follicle after parturition in cattle?

Answer 1

1. ovulates (CL and dominant follicle present)
2. LH pulse frequency isn’t sufficient enough for ovulation to occur so follicles turnover (negative energy balance, health…)
3. cystic (not large enough rise in oestrogen to cause LH surge and ovulation)

Question 2

what are some factors that will increase the number of inseminations per pregnancy?

Answer 2

drop in social status
caesarians and bad calving
mastitis
lameness
milk fever

Question 3

what can milk fever be a risk factor for?

Answer 3

difficult calving
retained foetal membranes
endometritis
subclinical low calcium (poor fertility)

Question 4

how does lameness effect the first oestrus and conceptions?

Answer 4

lame cows have first luteal activity after calving later, hence their first oestrus later and ultimately take longer to conceive

Question 5

what is a major cause of lame cows taking longer to conceive?

Answer 5

longer from calving to first oestrus
show less signs of oestrus (painful to walk around)

Question 6

how are follicles affected by mastitis?

Answer 6

follicles are smaller, LH pulse frequency is lower so growth isn’t being driven as heavily

Question 7

how can yield effect conception rates?

Answer 7

more silent heats as yield rises
less signs of oestrus

Question 8

how does nutrition effect fertility?

Answer 8

negative energy balance causes smaller follicles and less oestrogen release, this delays their first ovulation after calving and the signs of oestrus

Question 9

when approaching herd fertility issues, which cows should be focused on?

Answer 9

those causing the issues (worst performing cows)
this allows management and removal of risk factors for poor fertility