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THE EVALUATION OF NOOITGEDACHTER STALLIONS

IN SOUTH AFRICA’S FIRST NATIONAL EVALUATION TEST

 

1A. Theunissen, 2M.A. Snyman & 3M. van Dyk


1Vaalharts Research Station, Private Bag X9, Jan Kempdorp, 8550

2Grootfontein ADI, Private Bag X529, Middelburg EC, 5900

3P.O. Box 94, Vaalwater, 0530

 


1.  Introduction

The Nooitgedachter horse, which is pre-eminently known for its natural affection and affinity to people, is probably one of the scarcest horse breeds in the world and is indigenous to South Africa. It descended from the original Cape Horse from which the Basuto pony developed in the 18th and 19th centuries. The Basuto ponies had to fend for themselves in the inhospitable highlands of Lesotho (Basutoland) and inherited characteristics such as spiritedness, intelligence and stamina from their Oriental ancestors – the Arab, the Barb and the Javanese pony.

 

These traits made the Basuto pony eminently suitable for use as a military horse and as such, it was used during the Anglo-Boer War (1899-1902). It loyally served Boer and Briton alike. The pony’s fame spread and thousands of Basuto ponies were used as mounts in wars all over the world. Because of the mass export, drought and neglect, the Basuto pony teetered on the verge of extinction in Lesotho by the 1940s.

 

In 1951, the South African Department of Agriculture purchased a nucleus group of animals and initiated a breeding project at Nooitgedacht Research Station near Ermelo from where the Nooitgedachter developed. In 1967, eight separate studs were established as part of the breeding programme. In the same year the Nooitgedachter Breeders’ Association was established. The breed was recognised by the South African Stud Book Association as South Africa’s first indigenous horse breed in 1976. A year later, the Department of Agriculture sold its stud at a public auction, entrusting the further development of the Nooitgedachter to the Breeders’ Society. Since then the horse has proven itself as being very versatile. It is popular as a show horse, particularly as mount for women and children. It is also used as sport horse in gymkhana, jumping, endurance riding and hacking. On farms it is used for patrolling, livestock herding and game viewing (www.sa-breeders.co.za/org/nooitgedachter).

 

The first field test in which the performance of potential breeding sires from different studs was evaluated under the same conditions, was done in the Noupoort district. This was done in an attempt to improve the accuracy of selection of colts based on performance traits.

 

The objectives of this paper were to estimate phenotypic correlations between the traits scored in the stallion performance tests, in order to evaluate the various indices used for performance evaluations and to determine the opportunities of improving or simplifying the stallion performance tests for continued evaluation of young colts.     

 

2.  Materials and Methods

2.1  Description of the experimental location

The colts were kept for a year on a private farm, Winterhoek, in the Noupoort district in the Karoo region of the Republic of South Africa. The farm is representative of the extensive, low potential areas of the Karoo region. The climate is characterised by severe winters and hot summers.

 

2.2  Experimental animals and data recorded

During May 2001, 20 two-year old Nooitgedachter colts from different studs in the RSA were sent to the farm for a period of one year during which the colts were kept on the veld without any supplementation. They were all either studbook progeny (SP) or appendix B breeding material and were not subjected to any previous selection.

Only 17 colts were used in the final evaluation and selection, due to the death of one colt during the year, a balance problem in one colt due to an injury when he was still a young foal and another colt being injured during the training process. The colts in the project appear in Table 1 with their names, dates of birth, height measured at the time of evaluation and condition after the period of training.

 

Table 1. Details of colts in the first year of evaluation

Name

Date of birth

Height (cm)

Condition

Test number

Boesman

19-01-1999

142

Good

1

Lukas

12-12-1998

155

Good

2

Janu

14-01-1999

150

Good

3

Gulliver

13-12-1998

143

Reasonable

4

Cobra

01-01-1999

143

Good

5

Markus

09-01-1998

150

Good

6

Kwagga

01-11-1999

139

Good

7

Julius

03-12-1998

150

Excellent

8

Poon

16-02-1999

150

Reasonable

9

De Wet

22-11-1998

145

Excellent

11

Hoogmoed

05-11-1998

150

Excellent

12

Cedar

20-11-1998

149

Good

14

Legend

01-07-1999

138

Poor

15

Haastig

15-01-1999

143

Good

17

Ceaser

24-10-1998

146

Good

19

Spark

24-11-1998

150

Good

20

Parmant

10-05-1999

145

Good

21

 

A team of four young trainers backed and trained the colts during the fortnight of 22 March to 4 April 2002. The final evaluation was done on 5-6 April 2002 by the four young trainers, six national riders, six members of a national jury box and three senior selectors from the Breeders’ Society.

 

2.2.1  Conformation traits

Firstly, the six members of the jury box subjectively assessed several conformation traits. Table 2 gives a description of these traits, as well as the maximum score for each trait. A total score was calculated for each colt by adding its individual scores for all traits assessed. Subsequently, a conformation index was calculated for each colt, based on the total score.

 

Table 2. Means, standard errors, coefficients of variation and description of the traits analysed in this study

Trait

Max. score

Mean ± SE

CV (%)

Description of the trait

Conformation traits

Assessed by 6 members of the jury box (See 2.2.1)

Conformation

8

5.99±0.93

15.38

Good balance between the quarters, square on the legs, good posture and stand with hocks underneath, straight in proportion. Sturdy and compact.

Head

8

5.78±1.30

22.49

A lean, clean head with a straight profile. Good width between the eyes.  Nostrils must be flexible. Jaws well apart. Ears of medium size.  Must show type and character.

Head/Neck

8

5.07±0.81

15.98

Head set on correctly. Together, it forms the balancing mechanism of the horse. The attachment must not be coarse. Head must be able to bend so that nose can be carried in a vertical line. It must have definite muscle definition.

Neck length

8

6.58±1.28

19.45

Not too long or too short. It must be moderately long and must taper off to the attachment of the head.

Neck muscle

8

5.45±0.76

13.94

The neck must be flexible, not too thin or too thick. It must be longer at the top than the bottom.

Neck/Shoulder

8

5.60±1.06

18.93

Smooth attachment, high from the shoulder. Must be defined at the bottom chest attachment.

Shoulder length

8

5.55±0.70

12.61

Long from the top to the bottom of the shoulder blade across the middle. The blade must be broad for muscle attachment.

Shoulder angle

8

5.11±0.86

16.83

The angle between the middle of the shoulder blade and a horizontal line at the whither, must be as large as possible.

Whithers

8

6.70±0.98

14.63

Must be higher than the croup, but not too high so that saddle can do damage.

Back length

8

5.24±0.98

18.70

Not too long, with enough width and without a prominent spinal ridge. Flat.

Back

8

7.34±0.71

9.67

Not too long, with enough width and without a prominent spinal ridge. Flat.

Loin

8

5.94±0.88

14.81

It should be moderately short, broad and strong. An important indication of athleticism..

Croup

8

6.47±0.59

9.12

It should have width and in a more horizontal position. A slight slope is good.

Croup length

8

5.17±0.71

13.73

It should have length.

Thigh muscle

10

5.51±0.79

14.34

It must be well developed.

Front leg muscle

10

6.00±0.79

13.17

It must be well developed.

Stance of front legs from side

8

7.12±0.85

11.94

Square, straight and perpendicular.

Stance of hind legs from side

8

6.55±0.93

14.20

Square, straight, perpendicular and under the horse.

Stance of front legs from front

10

6.24±1.21

19.39

Square, straight and perpendicular.

Stance of hind legs from back

10

6.18±1.38

22.33

Square, straight, perpendicular and underneath.

Cannon bone

10

6.37±0.71

11.15

Tendons light, clean, strong and tight and broad looking from the front to the back. Must be straight, right under the knee, not too thin and 20 cm long. No contraction under the knee.

Front leg bone ratio

10

6.92±0.79

11.42

The cannon bone must be shorter than the upper leg

Hoofs

10

6.99±1.02

14.59

The angle, size, quality and form is taken into consideration.

Pastern angle

8

6.77±0.75

11.08

A 45-degree slope is usually considered correct.

Pastern length

8

6.28±0.91

14.65

Too long tends to the horizontal and strains the tendons and ligaments. Too short a pastern becomes vertical and does not break the jarring effect.

Tail attachment

8

7.18±0.81

11.28

Reasonably high, straight with the spine.

Constitution

10

6.61±1.52

23.00

Hardiness, a fine but strong bone structure and capacity. See flanks, ribs and coat quality.

Conformation trait index

 

100±7.55

7.55

Based on the total score for all traits awarded for each colt.

 

 

 

 

 

Riding traits

Assessed by 6 riders, 6 members of the jury box and 4 trainers (See 2.2.2)

Riding comfort

10

6.84±1.17

17.11

Ease of riding in all the gaits.

Walk

10

6.84±1.11

16.23

Good posture, ground cover, hoof placement, rhythm and motion. Acceptance of the bit.

Trot

10

6.14±1.55

25.24

Good posture, ground cover, hoof placement, rhythm and motion. Acceptance of the bit.

Canter

10

6.62±1.10

16.62

Good posture, ground cover, hoof placement, rhythm and motion. Acceptance of the bit.

Character

10

7.50±1.00

13.33

The horse must accommodate the rider and give his cooperation.

Temperament

10

7.64±1.18

15.45

Good-natured, fond of people, intelligent, spiritedness.

Manageability

10

7.32±0.99

13.52

Easy to handle and reliable.

Posture

10

7.04±1.19

16.90

A good appearance with nothing to spare; his form is one essentially of utility. The head is carried with pride. Bones are to carry weight and the muscles are the moving power.

Riding trait index

 

100±14.76

14.76

Based on the total score for all traits awarded for each colt.

 

 

 

 

 

Endurance test

See 2.2.3 for details

Initial pulse rate

 

40.41±4.56

11.28

Pulse rate before test

Recovered pulse rate 1

 

50.82±8.97

17.65

Pulse rate taken 10 minutes after arrival of 1st leg of test

 

Recovered pulse rate 2

 

52.29±8.49

16.24

Pulse rate taken 10 minutes after arrival of 2nd leg of test

Initial respiration rate

 

23.35±4.44

19.01

Respiration rate before test

Recovered respiration rate 1

 

28.47±5.56

19.53

Respiration rate taken 10 minutes after arrival of 1st leg of test

 

Recovered respiration rate 2

 

27.00±4.98

18.44

Respiration rate taken 10 minutes after arrival of 2nd leg of test

Endurance index

 

100±5.29

5.29

See 2.2.3

 

 

 

 

 

Total evaluation point

Combination of conformation traits, riding traits and score for movement (See 2.2.4)

Conformation traits

60

43.03±3.24

7.53

From total points awarded for conformation traits

Riding traits

30

21.01±3.09

14.71

From total points awarded for riding traits.

Movement

 

10

6.07±1.08

17.79

The extent to which the horse is propelled and covers ground, the proper use of his legs, neck, head, back, etc. Balance and rhythm.

Total evaluation point

 

100±9.08

9.08

See 2.2.4

 

 

 

 

 

Jumping ability

10

6.20±1.43

23.06

The height, willingness and strides.

 

 

 

 

 

Selection point

100

72.29±4.52

6.25

Assessed by 3 senior selectors (See 2.2.5)

 

 

 

 

 

 

2.2.2  Riding traits

Secondly, the six riders, the six members of the jury box and the four young trainers assessed eight riding (internal) traits. Table 2 gives a description of these traits, as well as the maximum score for each trait. Again, a total score was calculated for each colt by adding its individual scores for all traits assessed. Subsequently, a riding index was calculated for each colt, based on the total score.

 

2.2.3  Endurance test

Thirdly, the colts were subjected to an endurance test. The colts were taken for two successive rides of 2 km at a canter with an estimated speed of 13 km/h, with a resting period of 20 minutes between the rides. Pulse- and respiratory rates were taken before the test (initial rates), directly after arrival and also 10 minutes after arrival of the two rides. For the initial pulse and respiration rates, averages were calculated for the group of colts and indices were calculated for each colt. Colts with lower pulse- and respiratory rates were favoured with indices above 100 and vice versa for colts with higher counts than the average, due to the negative correlation between these rates and fitness in the horse.

 

The pulse and respiratory rates after the 10-minute recuperative period of each ride were taken as the recovered pulse or respiration rates after the respective rides. The extent, to which the colts’ pulse- and respiration rates recovered to the initial rates or the recuperative capability, was calculated as an index after each ride. All indices for each colt were summed and an index for endurance ability for each colt was calculated from these totals.

 

2.2.4  Total evaluation

Total evaluation indices were derived for each colt as follows: The evaluation committee recommended that conformation traits must account for 60% and the riding traits for 40% of the total evaluation point of each colt. The total points for conformation traits were recalculated to a point out of 60, whilst the total points for riding traits were recalculated to a point out of 30, in order to add a point for movement out of 10 points. Total evaluation indices were derived from the total points.

 

2.2.5  Selection point and jumping ability

A further selection point, awarded by the three senior selectors, was also given for each colt. Lastly, each colt’s jumping ability was evaluated under a rider, as there were no facilities where colts could be tested for free jumping. However, Gerber Olsson et al. (2000) estimated a genetic correlation of 0.93±0.23 between free jumping and jumping under a rider. Therefore jumping ability under a rider, instead of free jumping, can be included in the evaluation test if suitable facilities for free jumping are not available.

 

2.3  Data analyses

Data were analysed by means of the PROC CORR-procedures of SAS (SAS, 1990) to obtain correlations among and between assessed traits and calculated indices.

        

3.  Results and discussion

3.1  Means, standard deviation and coefficient of variation

The means, standard deviation and coefficient of variation for all traits assessed and calculated are presented in Table 2. The coefficients of variation of most of the traits assessed, fall within the range for the majority of biological production traits. Head, stance of hind legs from the back and constitution had the highest coefficients of variation of the assessed conformation traits, while back and croup had the lowest values. The conformation trait index, which includes all assessed conformation traits, however, had a low coefficient of variation (7.55%). The highest scores were awarded for back, stance of front legs from the side and tail attachment, while the lowest scores were given for thigh muscle and head/neck attachment.

 

With the exception of the coefficient of variation for trot of 25.24%, coefficients of variation for the riding traits ranged from 13.33% to 17.11%. These are similar to coefficients of variation (15.4 % to 19.2 %) obtained for riding traits by Gerber Olsson et al. (2000). Temperament had the highest mean score (7.64±1.18) and trot the lowest score (6.14±1.55). From Table 2 it is evident that there was more variation among colts with regard to riding traits (CV = 14.76%), when compared to conformation traits (CV = 7.55%).

 

As far as the endurance traits are concerned, slightly lower coefficients of variation were obtained for the various pulse rates, compared to the respiration rates. Very little variation was present among the colts with regard to endurance performance, as is evident from the low coefficient of variation of 5.29% for the endurance trait index.

 

A relatively large variation in jumping ability (CV = 23.06%) was present among the colts participating in the test. Furthermore, Gerber Olsson et al. (2000) estimated heritabilities of 0.47±0.13 for free jumping and 0.32±0.14 for jumping under a rider for Swedish riding horses in stallion performance tests. Similar heritability estimates of 0.30±0.17 and 0.31±0.17 were obtained by Huizinga et al. (1991a) for Dutch Warmblood riding horses. Therefore, jumping ability in the breed could be improved through selection based on individual sire performance.

 

Low coefficients of variation were calculated for the total evaluation point as well as for the selection point awarded by three senior selectors. Generally, individual traits had larger coefficients of variation than the calculated indices or points assessing a combination of traits.

 

3.2  Correlations among conformation traits

Correlations estimated among the various conformation traits are presented in Table 3. Significant positive phenotypic correlations, ranging from 0.53 to 0.71, were estimated among most of the traits relating to body dimensions, namely shoulder length, back length, croup length, croup, loin, thigh muscle and front leg muscle. 

 

Conformation and constitution were also positively correlated with each other (0.80), as well as with back length, loin, croup, croup length, thigh muscle and tail attachment.

 

Only a few significant correlations were estimated for leg and hoof traits. These were the correlations of 0.59 between cannon bone and hoofs, 0.55 between front leg bone ratio and shoulder angle, 0.49 between front leg bone ratio and back length, 0.52 between stance of hind legs and croup length, 0.57 between stance of hind legs and hoofs, 0.67 between stance of hind legs and stance of front legs and 0.52 between stance of hind legs and shoulder length.

 

Table 3. Correlations (P-value) among conformation traits

 

Confor-mation

Head

Head/

neck

Neck length

Neck muscle

Neck/

Shoulder

Shoulder length

Shoulder angle

Whithers

Back length

Back

Loin

Constitu-

tion

Confor-mation Index

Confor-mation

 

0.16(0.54)

0.05(0.85)

0.34(0.18)

-0.05(0.84)

0.49(0.05)

0.29(0.25)

-0.02(0.93)

0.27(0.29)

0.73(0.00)

0.33(0.19)

0.71(0.02)

0.80(0.00)

0.79(0.00)

Head

 

 

0.34(0.18)

0.31(0.23)

0.16(0.53)

0.27(0.29)

0.17(0.52)

0.44(0.08)

0.14(0.59)

0.32(0.20)

0.08(0.75)

0.28(0.28)

0.41(0.10)

0.34(0.18)

Head/

neck

 

 

 

-0.10(0.69)

0.45(0.07)

0.59(0.01)

-0.11(0.68)

0.17(0.51)

-0.34(0.19)

0.02(0.93)

-0.12(0.64)

-0.12(0.65)

0.10(0.71)

0.08(0.76)

Neck length

 

 

 

 

0.37(0.14)

0.23(0.38)

0.40(0.12)

0.48(0.05)

0.50(0.04)

0.25(0.32)

0.45(0.07)

0.14(0.59)

0.28(0.27)

0.50(0.01)

Neck muscle

 

 

 

 

 

0.62(0.01)

-0.22(0.40)

0.18(0.48)

0.08(0.77)

-0.19(0.46)

0.12(0.65)

-0.35(0.17)

-0.14(0.60)

0.11(0.67)

Neck/

Shoulder

 

 

 

 

 

 

0.03(0.92)

0.08(0.75)

0.07(0.79)

0.47(0.05)

-0.14(0.59)

0.11(0.67)

0.47(0.06)

0.52(0.03)

Shoulder length

 

 

 

 

 

 

 

0.71(0.00)

0.65(0.00)

0.42(0.09)

0.16(0.55)

0.35(0.16)

0.39(0.12)

0.69(0.00)

Shoulder angle

 

 

 

 

 

 

 

 

0.42(0.10)

0.17(0.51)

0.10(0.71)

0.02(0.95)

0.03(0.91)

0.44(0.08)

Whithers

 

 

 

 

 

 

 

 

 

0.17(0.52)

0.19(0.46)

0.26(0.32)

0.37(0.14)

0.52(0.03)

Back length

 

 

 

 

 

 

 

 

 

 

0.11(0.66)

0.67(0.00)

0.82(0.00)

0.74(0.00)

Back

 

 

 

 

 

 

 

 

 

 

 

0.26(0.30)

0.15(0.57)

0.39(0.13)

Loin

 

 

 

 

 

 

 

 

 

 

 

 

0.80(0.00)

0.58(0.01)

Constitution

 

 

 

 

 

 

 

 

 

 

 

 

 

0.72(0.00)

Croup

0.57(0.02)

0.18(0.49)

-0.31(0.23)

0.09(0.74)

-0.30(0.24)

0.15(0.56)

0.44(0.08)

0.03(0.90)

0.49(0.05)

0.66(0.00)

0.24(0.35)

0.43(0.09)

0.62(0.01)

0.64(0.01)

Croup length

0.69(0.00)

-0.08(0.77)

-0.39(0.12)

0.27(0.30)

-0.35(0.16)

-0.01(0.97)

0.56(0.02)

0.05(0.85)

0.40(0.11)

0.46(0.06)

0.29(0.26)

0.70(0.00)

0.57(0.02)

0.64(0.01)

Thigh muscle

0.62(0.01)

-0.06(0.81)

-0.32(0.22)

0.34(0.18)

-0.23(0.38)

0.08(0.76)

0.53(0.03)

0.11(0.68)

0.37(0.15)

0.55(0.02)

0.58(0.01)

0.46(0.06)

0.51(0.04)

0.69(0.00)

Front leg muscle

0.20(0.43)

-0.05(0.84)

-0.26(0.31)

0.09(0.72)

-0.11(0.67)

-0.02(0.93)

0.53(0.03)

0.21(0.41)

0.40(0.11)

0.36(0.15)

0.45(0.07)

0.14(0.60)

0.23(0.38)

0.49(0.05)

Stance front legs side

0.28(0.27)

0.37(0.14)

0.20(0.45)

0.25(0.34)

0.37(0.15)

0.31(0.22)

-0.04(0.87)

-0.03(0.92)

0.07(0.78)

0.17(0.50)

0.44(0.08)

0.08(0.76)

0.32(0.21)

0.43(0.09)

Stance front legs front

0.34(0.19)

-0.11(0.68)

0.28(0.27)

-0.24(0.36)

-0.17(0.52)

0.14(0.59)

0.31(0.22)

0.10(0.71)

-0.09(0.72)

0.36(0.15)

0.21(0.42)

0.30(0.24)

0.22(0.40)

0.37(0.14)

Stance hind legs side

0.33(0.18)

-0.11(0.67)

-0.32(0.20)

0.02(0.94)

-0.04(0.86)

0.07(0.80)

0.18(0.49)

0.09(0.72)

0.18(0.49)

0.13(0.63)

-0.04(0.88)

0.27(0.30)

0.10(0.71)

0.37(0.14)

Stance of hind legs back

0.34(0.19)

0.04(0.87)

0.31(0.23)

0.05(0.85)

0.01(0.97)

0.15(0.57)

0.52(0.03)

0.35(0.17)

0.21(0.41)

0.18(0.49)

0.26(0.31)

0.18(0.49)

0.27(0.30)

0.55(0.02)

Cannon bone

0.18(0.49)

0.54(0.02)

0.12(0.65)

0.20(0.45)

0.16(0.53)

0.21(0.41)

0.15(0.55)

0.48(0.05)

-0.01(0.96)

0.23(0.38)

0.18(0.49)

0.15(0.58)

0.00(1.00)

0.39(0.12)

Front leg bone ratio

0.05(0.85)

0.18(0.49)

0.31(0.22)

0.19(0.47)

0.07(0.78)

0.32(0.22)

0.45(0.07)

0.55(0.02)

-0.06(0.81)

0.49(0.04)

-0.07(0.76)

0.09(0.72)

0.23(0.37)

0.39(0.12)

Tail attach-

ment

0.69(0.00)

0.10(0.69)

-0.28(0.28)

0.17(0.50)

-0.26(0.31)

0.15(0.57)

0.24(0.35)

-0.20(0.44)

0.38(0.13)

0.53(0.03)

0.28(0.28)

0.64(0.01)

0.64(0.01)

0.60(0.01)

Hoofs

0.16(0.55)

0.05(0.85)

-0.14(0.58)

-0.15(0.57)

0.15(0.59)

0.16(0.53)

0.09(0.73)

0.21(0.41)

0.07(0.79)

0.20(0.44)

0.09(0.73)

0.07(0.78)

-0.11(0.67)

0.34(0.18)

Pastern angle

0.09(0.72)

-0.26(0.31)

-0.03(0.92)

0.24(0.34)

0.24(0.36)

0.33(0.20)

0.32(0.22)

0.24(0.35)

0.05(0.86)

0.23(0.38)

-0.02(0.94)

0.06(0.82)

-0.07(0.80)

0.34(0.18)

Pastern length

0.32(0.21)

-0.56(0.02)

-0.10(0.69)

0.15(0.56)

0.02(0.94)

0.28(0.27)

0.37(0.14)

-0.01(0.96)

0.19(0.46)

0.23(0.39)

-0.13(0.61)

0.07(0.78)

0.15(0.55)

0.38(0.13)

 

Table 3. Correlations among conformation traits (continued)

 

Croup length

Thigh muscle

Front leg muscle

Stance front legs side

Stance front legs front

Stance hind legs side

Stance of hind legs back

Cannon bone

Front leg bone ratio

Tail attach

Hoofs

Pastern angle

Pastern length

Croup

0.50(0.04)

0.65(0.00)

0.67(0.00)

0.21(0.42)

0.37(0.15)

0.14(0.60)

0.33(0.20)

0.15(0.58)

-0.03(0.92)

0.70(0.00)

0.27(0.30)

-0.05(0.84)

0.14(0.58)

Croup length

 

0.71(0.00)

0.43(0.09)

0.06(0.83)

0.24(0.36)

0.52(0.03)

0.30(0.24)

-0.05(0.86)

-0.05(0.85)

0.63(0.01)

0.10(0.69)

0.15(0.57)

0.49(0.05)

Thigh muscle

 

 

0.66(0.00)

0.30(0.25)

0.21(0.41)

0.35(0.16)

0.29(0.25)

0.18(0.49)

0.18(0.49)

0.57(0.02)

0.13(0.61)

0.18(0.48)

0.37(0.14)

Front leg muscle

 

 

 

0.13(0.62)

0.41(0.10)

0.01(0.96)

0.27(0.29)

0.00(1.00)

0.11(0.68)

0.29(0.26)

0.31(0.22)

0.49(0.85)

0.23(0.38)

Stance front legs side

 

 

 

 

-0.18(0.48)

0.25(0.33)

0.28(0.28)

0.37(0.15)

0.20(0.44)

0.34(0.18)

0.14(0.59)

-0.12(0.65)

-0.02(0.93)

Stance front legs front

 

 

 

 

 

-0.23(0.37)

0.67(0.00)

-0.05(0.84)

0.14(0.60)

0.11(0.66)

0.19(0.46)

0.23(0.38)

0.17(0.52)

Stance hind legs side

 

 

 

 

 

 

0.04(0.88)

0.40(0.12)

0.08(0.76)

0.40(0.11)

0.57(0.02)

0.27(0.29)

0.40(0.11)

Stance of hind legs back

 

 

 

 

 

 

 

0.15(0.58)

0.26(0.31)

0.15(0.57)

0.04(0.88)

0.14(0.59)

0.25(0.33)

Cannon bone

 

 

 

 

 

 

 

 

0.30(0.24)

-0.01(0.96)

0.59(0.01)

0.13(0.62)

-0.31(0.22)

Front leg bone ratio

 

 

 

 

 

 

 

 

 

-0.18(0.50)

0.10(0.71)

0.42(0.09)

0.25(0.33)

Tail attach

 

 

 

 

 

 

 

 

 

 

0.18(0.49)

0.09(0.73)

0.35(0.17)

Hoofs

 

 

 

 

 

 

 

 

 

 

 

0.34(0.18)

0.05(0.85)

Pastern angle

 

 

 

 

 

 

 

 

 

 

 

 

0.60(0.01)

 

3.3  Correlations among riding traits

Estimated correlations among the various riding traits are summarised in Table 4. From the table it is evident that all riding traits assessed were significantly correlated with each other. The highest genetic as well as phenotypic correlations among the three gaits were estimated between trot and gallop. Gerber Olsson et al. (2000) reported the same result, namely a genetic correlation of 0.71±0.16 between trot and gallop. High heritabilities, ranging from 0.37 to 0.73 were also reported by Gerber Olsson et al. (2000) and Huizinga et al. (1991a, 1991b) for the different gaits, suggesting that genetic improvement of the gaits is possible through selection based on sire evaluation tests.

 

Table 4. Correlations among riding traits

 

Walk

Trot

Canter

Character

Tempera-ment

Manage-ability

Posture

Riding Index

Riding comfort

0.90(0.00)

0.92(0.00)

0.93(0.00)

0.73(0.00)

0.69(0.00)

0.76(0.00)

0.90(0.00)

0.97(0.00)

Walk

 

0.84(0.00)

0.84(0.00)

0.66(0.00)

0.61(0.01)

0.60(0.01)

0.75(0.00)

0.89(0.00)

Trot

 

 

0.95(0.00)

0.55(0.02)

0.58(0.02)

0.61(0.01)

0.79(0.00)

0.89(0.00)

Canter

 

 

 

0.62(0.01)

0.63(0.01)

0.65(0.01)

0.85(0.00)

0.92(0.00)

Character

 

 

 

 

0.94(0.00)

0.91(0.00)

0.67(0.00)

0.84(0.00)

Temperament

 

 

 

 

 

0.87(0.00)

0.57(0.02)

0.82(0.00)

Manageability

 

 

 

 

 

 

0.78(0.00)

0.85(0.00)

Posture

 

 

 

 

 

 

 

0.89(0.00)

 

3.4  Correlations between riding and conformation traits

These correlations are summarised in Table 5. Riding comfort, posture and the various gaits (walk, trot and canter) were all significantly positively correlated with neck length, shoulder length, shoulder angle, whithers, croup, stance of hind legs, conformation and constitution. A correlation of 0.70 was estimated between conformation trait index and riding trait index, indicating that horses that performed better in the riding evaluation, also received higher scores for the conformation traits during the latter assessment. Simultaneous selection for improved riding traits and for conformation traits, without any detrimental effect on any trait, is therefore possible.

 

Table 5. Correlations between riding traits and conformation traits

 

Riding comfort

Walk

Trot

Canter

Character

Tempera-ment

Manage-ability

Posture

Riding

Index

Conformation

0.36(0.16)

0.32(0.22)

0.43(0.09)

0.47(0.06)

0.35(0.17)

0.36(0.16)

0.27(0.30)

0.26(0.32)

0.41(0.11)

Head

0.30(0.24)

0.24(0.35)

0.06(0.83)

0.15(0.58)

0.63(0.01)

0.52(0.03)

0.41(0.10)

0.24(0.35)

0.35(0.17)

Head/neck

0.03(0.92)

0.10(0.71)

-0.01(0.96)

0.01(0.95)

-0.02(0.95)

-0.22(0.40)

-0.09(0.72)

0.23(0.38)

0.01(0.97)

Neck length

0.43(0.08)

0.50(0.04)

0.45(0.07)

0.45(0.07)

0.46(0.06)

0.58(0.01)

0.24(0.35)

0.19(0.46)

0.48(0.05)

Neck muscle

0.03(0.90)

0.15(0.57)

0.05(0.85)

0006(0.81)

0.03(0.90)

0.01(0.96)

-0.11(0.67)

0.14(0.60)

0.06(0.82)

Neck/Shoulder

0.30(0.23)

0.38(0.13)

0.31(0.22)

0.39(0.12)

0.38(0.13)

0.25(0.33)

0.27(0.29)

0.47(0.05)

0.39(0.12)

Shoulder length

0.74(0.00)

0.57(0.02)

0.65(0.00)

0.74(0.00)

0.54(0.03)

0.40(0.01)

0.66(0.00)

0.71(0.00)

0.73(0.00)

Shoulder angle

0.43(0.08)

0.41(0.10)

0.42(0.10)

0.31(0.22)

0.35(0.16)

0.44(0.08)

0.34(0.18)

0.41(0.10)

0.44(0.08)

Whithers

0.38(0.00)

0.43(0.08)

0.72(0.00)

0.70(0.00)

0.47(0.06)

0.63(0.01)

0.55(0.02)

0.59(0.01)

0.68(0.00)

Back length

0.37(0.15)

0.38(0.14)

0.35(0.17)

0.49(0.05)

0.60(0.01)

0.60(0.01)

0.53(0.03)

0.35(0.17)

0.51(0.04)

Back

0.02(0.94)

-0.10(0.70)

0.07(0.79)

0.07(0.78)

0.01(0.97)

0.14(0.59)

-0.04(0.88)

-0.14(0.61)

0.01(0.97)

Loin

0.28(0.27)

0.18(0.48)

0.29(0.27)

0.38(0.12)

0.33(0.20)

0.35(0.17)

0.26(0.32)

0.15(0.55)

0.32(0.21)

Croup

0.44(0.08)

0.23(0.37)

0.42(0.09)

0.44(0.08)

0.59(0.01)

0.66(0.04)

0.72(0.00)

0.42(0.09)

0.54(0.03)

Croup length

0.38(0.14)

0.24(0.36)

0.34(0.19)

0.42(0.09)

0.32(0.22)

0.36(0.15)

0.34(0.19)

0.26(0.32)

0.38(0.13)

Thigh muscle

0.25(0.34)

0.06(0.83)

0.27(0.30)

0.34(0.19)

0.36(0.16)

0.47(0.06)

0.44(0.07)

0.21(0.41)

0.33(0.20)

Front leg muscle

0.23(0.37)

-0.01(0.98)

0.18(0.49)

0.31(0.26)

0.30(0.25)

0.39(0.12)

0.46(0.06)

0.35(0.17)

0.29(0.25)

Stance front legs side

0.10(0.69)

0.07(0.77)

-0.02(0.94)

0.00(1.00)

0.35(0.17)

0.30(0.24)

0.23(0.37)

0.14(0.60)

0.16(0.55)

Stance front legs front

0.26(0.31)

0.24(0.35)

0.30(0.23)

0.35(0.17)

0.02(0.94)

-0.02(0.93)

0.18(0.50)

0.32(0.20)

0.24(0.35)

Stance hind legs side

-0.03(0.91)

-0.06(0.82)

-0.10(0.70)

-0.06(0.82)

0.00(1.00)

0.05(0.85)

0.04(0.87)

-0.01(0.98)

-0.02(0.93)

Stance of hind legs back

0.57(0.02)

0.53(0.03)

0.53(0.03)

0.51(0.04)

0.27(0.29)

0.25(0.33)

0.41(0.11)

0.57(0.03)

0.52(0.03)

Cannon bone

0.12(0.65)

0.13(0.63)

-0.08(0.77)

-0.01(0.97)

0.28(0.28)

0.25(0.34)

0.21(0.41)

0.08(0.75)

0.13(0.63)

Front leg bone ratio

0.21(0.41)

0.35(0.16)

0.14(0.61)

0.28(0.27)

0.31(0.22)

0.31(0.23)

0.28(0.28)

0.31(0.21)

0.30(0.24)

Tail attachment

0.26(0.32)

0.10(0.70)

0.29(0.25)

0.23(0.37)

0.38(0.13)

0.41(0.11)

0.42(0.09)

0.20(0.45)

0.32(0.21)

Hoofs

-0.05(0.84)

-0.09(0.73)

-0.14(0.58)

-0.05(0.85) )

-0.06(0.83)

-0.02(0.93)

0.04(0.88)

0.06(0.82)

-0.06(0.83)

Pastern angle

0.26(0.31)

0.40(0.11)

0.31(0.23)

0.31(0.22)

0.11(0.68)

0.10(0.70)

0.17(0.51)

0.30(0.24)

0.29(0.26)

Pastern length

0.25(0.33)

0.30(0.23)

0.35(0.17)

0.34(0.19) )

0.05(0.84)

0.07(0.79)

0.18(0.50)

0.35(0.17)

0.28(0.28)

Constitution

0.48(0.05)

0.38(0.12)

0.47(0.05)

0.57(0.02)

0.65(0.01)

0.63(0.01)

0.54(0.02)

0.43(0.08)

0.59(0.01)

Conformation Index

0.64(0.01)

0.54(0.02)

0.58(0.01)

0.68(0.00)

0.64(0.01)

0.66(0.00)

0.62(0.01)

0.62(0.01)

0.70(0.00)

 

3.5  Correlations among traits measured during the endurance trial

From Table 6 it is evident that there was no significant correlation between pulse rate and respiration rate, neither between initial pulse rate and recovered pulse rates taken after the two legs of the trial. Initial respiration rate was, however, positively correlated with the recovered respiration rates.

 

Table 6. Correlations among traits measured during the endurance trial (endurance traits)

 

Recovered pulse rate 1

Recovered pulse rate 2

Initial respiration rate

Recovered respiration rate 1

Recovered respiration rate 2

Endurance index

Initial pulse rate

0.42(0.10)

0.38(0.13)

0.19(0.46)

0.03(0.92)

0.13(0.61)

-0.13(0.62)

Recovered pulse rate 1

 

0.72(0.00)

0.10(0.70)

-0.16(0.55)

0.03(0.90)

-0.62(0.01)

Recovered pulse rate 2

 

 

0.14(0.58)

0.01(0.96)

-0.02(0.94)

-0.70(0.00)

Initial respiration rate

 

 

 

0.51(0.04)

0.74(0.00)

-0.37(0.15)

Recovered respiration rate 1

 

 

 

 

0.38(0.13)

-0.51(0.03)

Recovered respiration rate 2

 

 

 

 

 

-0.41(0.10)

 

3.6  Correlations of riding and conformation traits with endurance index, movement, jumping ability and selection point

These correlations are summarised in Table 7. Endurance index was significantly correlated with conformation (0.70), constitution (0.58), most of the traits relating to neck, back, loin and croup, as well as with most of the riding traits. However, there were no significant correlations between endurance index and leg and hoof traits.

Movement was only correlated with pastern angle, trot and canter, while jumping ability was only significantly related to stance of front legs, riding comfort and trot. Selection point was positively correlated with all the riding traits, as well as with constitution, shoulder traits, back length and stance of front and hind legs.

 

Table 7. Correlations of riding and conformation traits with endurance index, movement, jumping ability and selection point

 

Endurance index

Movement

Jumping ability

Selection point

Conformation

0.70(0.00)

0.24(0.35)

0.21(0.42)

0.46(0.06)

Head

0.41(0.10)

0.12(0.63)

-0.01(0.96)

0.35(0.17)

Head/neck

-0.03(0.88)

0.08(0.76)

0.05(0.85)

0.43(0.09)

Neck length

0.51(0.04)

0.32(0.21)

-0.02(0.95)

0.43(0.09)

Neck muscle

-0.10(0.69)

0.11(0.68)

-0.02(0.95)

0.24(0.35)

Neck/Shoulder

0.25(0.33)

0.39(0.12)

0.17(0.51)

0.59(0.01)

Shoulder length

0.60(0.01)

0.26(0.32)

0.22(0.40)

0.61(0.01)

Shoulder angle

0.54(0.02)

0.14(0.59)

0.05(0.85)

0.47(0.05)

Whithers

0.34(0.18)

0.26(0.31)

0.19(0.47)

0.36(0.15)

Back length

0.64(0.01)

0.37(0.14)

0.14(0.58)

0.56(0.02)

Back

0.25(0.33)

-0.09(0.72)

0.12(0.65)

0.18(0.49)

Loin

0.60(0.01)

0.24(0.36)

0.01(0.97)

0.31(0.22)

Croup

0.46(0.06)

0.04(0.86)

0.40(0.11)

0.33(0.19)

Croup length

0.63(0.01)

0.04(0.88)

0.01(0.98)

0.19(0.48)

Thigh muscle

0.53(0.03)

-0.06(0.81)

0.07(0.78)

0.25(0.33)

Front leg muscle

0.20(0.45)

-0.02(0.93)

0.18(0.49)

0.25(0.34)

Stance front legs side

0.03(0.91)

-0.34(0.18)

-0.14(0.60)

0.15(0.56)

Stance front legs front

0.32(0.22)

0.16(0.34)

0.58(0.01)

0.52(0.03)

Stance hind legs side

0.33(0.20)

-0.24(0.36)

-0.16(0.54)

-0.17(0.52)

Stance of hind legs back

0.42(0.09)

-0.18(0.48)

0.41(0.10)

0.55(0.02)

Cannon bone

0.49(0.05)

-0.02(0.94)

0.20(0.45)

0.20(0.44)

Front leg bone ratio

0.26(0.31)

0.11(0.67)

-0.17(0.52)

0.45(0.07)

Tail attachment

0.34(0.18)

0.10(0.71)

0.27(0.30)

0.26(0.31)

Hoofs

0.20(0.45)

0.08(0.75)

0.32(0.22)

0.09(0.72)

Pastern angle

0.20(0.45)

0.48(0.05)

0.40(0.11)

0.50(0.04)

Pastern length

0.10(0.70)

0.14(0.58)

0.09(0.72)

0.28(0.27)

Constitution

0.58(0.02)

0.23(0.36)

0.00(1.00)

0.49(0.04)

Riding comfort

0.50(0.04)

0.45(0.07)

0.47(0.05)

0.75(0.00)

Walk

0.50(0.04)

0.46(0.06)

0.42(0.10)

0.73(0.00)

Trot

0.43(0.08)

0.52(0.03)

0.53(0.03)

0.73(0.00)

Canter

0.52(0.03)

0.55(0.02)

0.40(0.11)

0.77(0.00)

Character

0.53(0.03)

0.23(0.36)

0.18(0.50)

0.57(0.02)

Temperament

0.59(0.01)

0.17(0.52)

0.12(0.66)

0.49(0.05)

Manageability

0.44(0.07)

0.16(0.53)

0.35(0.17)

0.56(0.02)

Posture

0.31(0.22)

0.39(0.12)

0.44(0.08)

0.76(0.00)

 

3.7  Correlations among indicators for evaluation of excellence

Correlations among the various calculated indices/points, movement, jumping ability and the selection point are presented in Table 8. With the exception of movement and jumping ability, significant positive correlations were estimated among the traits in Table 8. Movement was only correlated with total evaluation point, which was to be expected, as it forms part of the total evaluation point. Jumping ability was not significantly related to any of the other performance indicators.

 

Table 8. Correlations among indicators for evaluation of excellence

 

Riding index

Endurance index

Total evaluation point

Movement

Jumping ability

Selection point

Conformation index

0.70(0.00)

0.76(0.00)

0.90(0.00)

0.26(0.31)

0.30(0.24)

0.73(0.00)

Riding index

 

0.55(0.02)

0.92(0.00)

0.43(0.09)

0.42(0.10)

0.77(0.00)

Endurance index

 

 

0.69(0.00)

0.18(0.48)

0.19(0.48)

0.48(0.05)

Total evaluation point

 

 

 

0.51(0.03)

0.44(0.08)

0.87(0.00)

Movement

 

 

 

 

0.47(0.06)

0.63(0.01)

Jumping ability

 

 

 

 

 

0.59(0.01)

 

4.  Conclusion

Numerous traits were assessed during the evaluation test. Many of these have no significant relation to any of the other functionally important traits. The number of traits could possibly be reduced to include only those with a significant relation to the indicators of excellence. Some of these traits could even be measured objectively, instead of being assessed subjectively.

Correlations estimated among the traits assessed during the sire evaluation test, together with information obtained from the literature, indicate that such a test could be an efficient tool for the selection of breeding stallions for breed improvement, as well as for the development of specific lines for the different equestrian disciplines. It can also be deduced that the evaluation test can improve the accuracy of selection and that future breeding programmes can benefit from the project.

More data from further tests are needed to estimate genetic parameters for the traits assessed, and to build up a database for Nooitgedachter stallions in South Africa.

 

5.   Acknowledgement

The authors are indebted to the Nooitgedachter Breeders’ Society for allowing them to analyse the data.

 

6.   References

Gerber Olsson, E., Arnason, T., Näsholm, A. & Philipsson, J., 2000. Genetic parameters for traits at performance test of stallions and correlations with traits at progeny tests in Swedish warm blood horses. Livestock Production Science, 65 : 81 – 89.

Huizinga, H.A., Van der Werf, J.H.J., Korver, S. & Van der Meil, G.J.W., 1991a. Stationary performance testing of stallions from the Dutch Warmblood riding horse population. 1. Estimated genetic parameters of scored traits and the genetic relation with dressage and jumping competition from offspring of breeding stallions. Livest. Prod. Sci. 27(2/3) : 231 - 244

Huizinga, H.A., Van der Werf, J.H.J., Korver, S. & Van der Meil, G.J.W., 1991b. Stationary performance testing of stallions from the Dutch Warmblood riding horse population. 2. Estimated heritabilities of and correlations between successive judgements of performance traits. Livest. Prod. Sci. 27(2/3) : 245 – 254

SAS Institute. Inc., SAS Procedures Guide, Version 6, 3rd Ed., Cary, NC : SAS Institute. Inc., 1990.

 

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Karoo Agric 6 (1)