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Table 1 Pre-ovulatory follicular growth rates: a comparison between the first ovulation after winter anoestrus and later ovulations in the same mares

From: Growth rate of ovulatory follicles during the first ovulatory oestrus (after seasonal anoestrus) and subsequent oestrous period in Irish Draught mares

 

Follicle diameters up to 11 days before ovulation (mm)

Days before ovulation

−11

−10

−9

−8

−7

−6

−5

−4

−3

−2

−1

0

First ovulations of the season

Jan 14th to Feb 22nd

No. of observations

15

16

16

16

16

16

16

16

16

16

16

16

Mean diameter

20

23.5

26

27.7

30.1

33.1

34.3

36.2

39.1

41.7

43.5

44.6

Feb 25th to May 22nd

No. of observations

16

16

16

16

16

16

16

16

16

16

16

16

Mean diameter (mm)

20.3

22.3

25

27.5

30.1

33.3

35

38

40.2

42.1

42.7

44.8

Jan 14th to May 22nd

Total no. of observations

31

32

32

32

32

32

32

32

32

32

32

32

Mean diameter (mm)

20.1

22.9

25.5

27.6

30.1

33.2

34.6

37.1

39.6

41.9

43.1

44.7

Range (mm)

<10-36

<10-37

10-41

10-43

10-44

12-45

15-48

18-48

20-53

25-55

31-57

35-59

Subsequent ovulations

Jan 15th to Mar 12th

No of observations

2

4

3

4

9

5

11

11

14

15

14

17

Mean diameter (mm)

19

24.8

20.3

25.8

28.2

32.6

34.7

36.6

39.3

41.9

44.8

44.2

Mar 14th to June 16th

No. of observation

3

3

3

5

5

8

7

11

13

14

17

17

Mean diameter (mm)

26

23.6

29.2

28.2

31.4

30.4

33.7

36.5

39

41.5

41.6

42.8

Jan 15th to June 16th

No. of observations

5

7

6

9

14

13

18

22

27

29

31

34

Mean diameter (mm)

23.2

24.3

24.8

27.1

29.3

31.3

34.3

36.5

39.1

41.7

43

43.5

Range (mm)

14 - 32

17 - 34

18 -36

16 -37

15 -41

23- 39

24 - 43

24.5-47

26 - 52

27.5-52

31.5-55

31-57.5

Difference in mean diameters

−3.1

−1.4

0.7

0.5

0.8

1.9

0.3

0.6

0.5

0.2

0.1

1.2

Mean growth rate (mm/day)

Day −11 to 0

 

Day −8 to 0

 

Day −5 to 0

       

First ovulations

2.20

 

2.14

 

2.02

       

Subsequent ovulations

2.19

 

2.37

 

1.84

       

Difference

0.01

 

0.23

 

0.18