Table 2 Normal sperm head morphometry of Thai native crossbred (T; T1 – T5) and purebred (F; F1 – Standardbred; F2 – Warmblood; F3 and F4 – Thoroughbred) stallions (mean ± SE)

6.24 ± 0.03^a

2.99 ± 0.02^a

0.35 ± 0.002^a

15.98 ± 0.04^a

15.88 ± 0.09^a,b

2.09 ± 0.01^a

0.78 ± 0.002^a

1.63 ± 0.006^a

0.92 ± 0.004^a

6.07 ± 0.02^b

3.19 ± 0.02^b

0.31 ± 0.003^b

15.73 ± 0.04^b

16.23 ± 0.09^b

1.90 ± 0.01^b

0.82 ± 0.002^b

1.57 ± 0.007^b

0.94 ± 0.003^b

6.33 ± 0.02^c

3.19 ± 0.01^b

0.33 ± 0.002^c

16.10 ± 0.04^a

16.67 ± 0.08^c

1.98 ± 0.01^c

0.81 ± 0.001^c

1.60 ± 0.005^c

0.95 ± 0.002^b

6.18 ± 0.02^ab

3.11 ± 0.02^c

0.33 ± 0.003^c

15.76 ± 0.04^b

15.90 ± 0.09^a,b

1.99 ± 0.01^c

0.80 ± 0.002^c

1.60 ± 0.008^b,c

0.95 ± 0.004^b

6.18 ± 0.02^a

3.08 ± 0.01^c

0.33 ± 0.002c

15.71 ± 0.03^b

15.77 ± 0.07^a

2.02 ± 0.01^c

0.80 ± 0.002^c

1.61 ± 0.005^a,c

0.95 ± 0.002^b

6.22 ± 0.01*

3.09 ± 0.0*

0.34 ± 0.001*

15.88 ± 0.02*

16.09 ± 0.03*

2.01 ± 0.005*

0.80 ± 0.001*

1.61 ± 0.003*

0.94 ± 0.002*

4.5

6.2

8.5

3.3

6.6

6.5

3.3

4.6

4.2

6.00/6.40

2.90/3.20

0.31/0.35

15.60/16.20

15.40/16.80

1.94/2.10

0.79/0.82

1.56/1.66

0.92/0.97

5.94 ± 0.02^a

2.99 ± 0.01^a

0.33 ± 0.002^a

15.14 ± 0.03^a

14.83 ± 0.07^a

1.99 ± 0.07^a

0.81 ± 0.001^a

1.62 ± 0.004^a

0.94 ± 0.002^a

5.98 ± 0.01^a

2.92 ± 0.01^b

0.34 ± 0.002^b

14.89 ± 0.03^b

13.97 ± 0.05^b

2.06 ± 0.01^b

0.79 ± 0.002^b

1.62 ± 0.004^a

0.98 ± 0.001^b

6.15 ± 0.03^b

2.92 ± 0.01^b

0.36 ± 0.002^c

15.24 ± 0.05^a

14.41 ± 0.09^c

2.11 ± 0.01^c

0.78 ± 0.002^c

1.64 ± 0.006^b

0.98 ± 0.003^bc

5.85 ± 0.01^c

2.80 ± 0.01^c

0.35 ± 0.001^c

14.55 ± 0.03^c

13.20 ± 0.05^d

2.09 ± 0.01^c

0.79 ± 0.001^c

1.64 ± 0.004^b

0.98 ± 0.002^c

5.94 ± 0.08

2.89 ± 0.01

0.35 ± 0.001

14.88 ± 0.02

13.90 ± 0.04

2.06 ± 0.004

0.79 ± 0.001

1.63 ± 0.002

0.97 ± 0.001

5

6.5

8.8

4

8.5

6.8

3.4

4.7

3.5

5.70/6.20

2.80/3.10

0.33/0.36

14.50/15.20

13.10/14.70

1.97/2.14

0.77/0.81

1.58/1.68

0.95/0.99