Week 2 - Species Differences in Oestrus Cycle

Question 1

State the average Length of Oestrus cycle for (days):
- Cow
- Ewe
- Sow
- Mare
- Bitch

Answer 1

21-22

17

21

21-23

about 210

Question 2

State the average duration of Oestrus for:
- Cow
- Ewe
- Sow
- Mare
- Bitch

Answer 2

5-18 hours

24-36 hours

48-72 hours

4-8 days

7-14 days

Question 3

For Cow:
How long is oestrus?
- When do they ovulate?
- Why does this make mating timing easy?
- Why does the length of oestrus make cows difficult?

Answer 3

5-18 hours

12 hours after oestrus

mate at oestrus or a few hours later

there is a very small window to detect oestrus

Question 4

State the average timing of ovulation for:
- Cow
- Ewe
- Sow
- Mare
- Bitch

Answer 4

12 hours after end of oestrus

30-36 hours from beginning of oestrus

35-45 hours form beginning of oestrus

1-2 days before end of oestrus

often 2 days after onset of standing oestrus

Question 5

For Ewe:
- How long is oestrus?
- When do they ovulate?
- Why are ewes generally easy to inseminate? (2)
- What are the biggest problems for inseminating ewes? (2)

Answer 5

24-36 hours

30-36 hours from beginning of oestrus

they can be mated throughout oestrus
ram can run with ewes so ram is detecting oestrus

getting the correct ram to ewe ratio
identifying mated ewes

Question 6

For Mare:
- How long is oestrus?
- When do they ovulate?
- Why are Mares problematic for optimising mating time? (2)
- Therefore, what is normal practice for mating mares? (3)
- Give an example of a Clinical tool that can be used to check for the optimum time to mate

Answer 6

4-8 days

1-2 days before end of oestrus

the length of oestrus is variable and we don’t know how long it will be until it has ended
and they ovulate during oestrus

tease mare with a less valuable stallion daily to detect oestrus
use clinical tools to determine optimum time to mate
start mating from onset of oestrus signs

ultrasounding the ovaries

Question 7

For Sow:
- How long is oestrus?
- When do they ovulate?
- Why is oestrus detection so important for sows?
- When after oestrus detection would we mate them?
- If artificially inseminating, how many rounds would we do?

Answer 7

48-72 hours

35-45 hours

because the sow and boar are housed separately
so sow must be presented to boar for mating

one day after oestrus

2

Question 8

For Bitch:
- How long is oestrus?
- When do they ovulate?
- Why is it important to detect oestrus?
- What clinical tools do we use to detect oestrus? (2)

Answer 8

7-14 days

often 2 days after onset of standing oestrus

because oestrus cycle is 210 days long
so next fertile window could be over 200 days away

vaginal cytology
plasma progesterone concentration

Question 9

Oestrus Behaviour in Cows:
- When does 70% of their oestrus behaviour occur?
- When would be a bad time to be observing for oestrus behaviour in cows? (2)

Answer 9

at night

when bringing them in for milking
when feeding

Question 9

Oestrus Behaviour in Cows:
- State the gold standard for detecting oestrus and the optimal time to mate in cows
- State other signs of oestrus and when they are likely to be displayed (5)

Answer 9

standing to be mounted by another cow or bull

mounting other cows
- coming into heat and standing heat

reduced yield of milk
restlessness
chin pressing
- mostly coming into heat

swelling of vulva, mucous discharge
- coming into heat, standing heat, going out of heat

Question 10

Oestrus Detection in Cows:
- Give details of 3 ways of detecting oestrus in cows

Answer 10

observing cows at least 4 times a day for 30 minutes a time

using detection aids that change appearance when another cow mounts

electronic aids monitoring cow movements

Question 10

Oestrus Behaviour in Cows:
- State the name of a key indicator, commonly displayed by bull, that the cow is in oestrus?
- Explain it (2)

Answer 10

flehmen reaction

curling of the lip
to present all the pheromones to the vomeronasal organs

Question 11

Oestrus Detection in Cows:
State factors that might inhibit oestrus behaviour (7)

Answer 11

hard slippery floors
high environmental temperatures
high milk yield
overcrowding
recent stress
lameness
feeding

Question 12

Oestrus Detection in Cows:
What clinical assessments would suggest a cow is in oestrus?

Answer 12

low plasma or milk progesterone

ultrasonography showing a large dominant follicle and no corpus luteum

Question 13

Oestrus Detection in Cows:
- How can you make oestrus detection easier?
- how does it work?
- Give 2 benefits of it

Answer 13

synchronising ovulation with ovsynch

giving GnRH and progesterone
so we know when ovulation is going to occur

it almost removes the need for oestrus detection
it reduces the time from calving to oestrus detection

Question 14

Oestrus Detection in Ewe:
- Give common oestrus behaviours (6)
- in an AI set up, how would you detect oestrus?

Answer 14

restless
stands for ram
waggles tail
moves tail laterally to allow mating
swollen vulva
vulval discharge

use a vasectomised ram with a raddle

Question 15

Oestrus Detection in Sow:
The time from weaning to coming into oestrus is very consistent in sow
- how long is it?
- When should you NOT observe for oestrus?
- How often should you observe for oestrus?

Answer 15

5-7 days

when feeding

multiple times a day

Question 16

Oestrus Detection in Sow:
Give common signs of oestrus in sow
- If using AI, how far apart should you give the AI rounds?

Answer 16

stands firmly to be mounted
swollen red vulva prior to oestrus
restless

12-24 hours apart

Question 17

Oestrus Detection in Mare:
- Why is it so important to accurately detect oestrus in mares (in terms of safety)?
- The presence of what factor can minimise oestrus signs?
- Give typical signs of oestrus (6)

Answer 17

because a mare not in oestrus can lead to damage of the stallion

a foal

swollen vulva
vulval discharge
elevated tail
spreading of hindlimbs
winking (repeated exposure of clitoris)
flehmen reaction from stallion

Question 18

Oestrus Detection in Mare:
- Clinically, what are we looking for in a clinical assessment to determine the mare is in oestrus? (3)

Answer 18

a large follicle of more than 20mm
absence of corpus luteum
thickened follicle wall

Question 19

Oestrus Detection in Bitch:
- How long is Pro-oestrus in Bitch?
- What behaviour do you expect during this period?
- What clinical signs do you expect during this period? (2)

Answer 19

about 9 days

the bitch is attractive but will not allow mating

swollen vulva
red serosanguinous discharge

Question 20

Oestrus Detection in Bitch:
- How long is the Oestrus period in Bitches?
- Give signs of being in oestrus (4)

Answer 20

about 9 days

stands to be mated
deviation of tail
discharge becomes paler
reduction in vulval swelling

Question 21

Oestrus Detection in Bitch:
If assessing Oestrus Clinically-
We can do Vaginal cytology or Plasma concentration of progesterone
- What are we looking to detect in Plasma Progesterone conc that is different from other species?

Answer 21

a rise in progesterone that precedes ovulation

Question 22

Oestrus Detection in Queen:
- What type of Ovulation is the Queen?
- Give signs of oestrus (6)

Answer 22

induced ovulation

increased vocalisation
rubbing and rolling
stands to be mated by lowering front quarters
tail erect and deviated
increased activity
possible vulval discharge