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EVALUATION OF GENETIC FINE WOOL ANIMALS UNDER NATURAL CONDITIONS IN THE

NON-TRADITIONAL FINE WOOL PRODUCING AREAS OF THE RSA

 

W.J. Olivier1# and J.J. Olivier2

1 Grootfontein ADI, Private Bag X529, Middelburg E.C. 5900

2 ARC: LBD (Animal Production), Private Bag X5013, Stellenbosch, 7590

#Corresponding author: E-mail: WJ Olivier

 


INTRODUCTION

During the past two decades there was a shift in the demand of wool, away from strong wool to fine wool. Prior to this, the proportion of fine wool (20 µm and finer) in the national clip, decreased from 69% in 1951/55 to only 4% in 1976/80 (Marx, 1981). This decrease was mainly due to more emphasis being placed on the selection for the amount of wool produced in the 1950's and 1960's. The price premium paid for finer wool during the 1980's lead to more emphasis being placed on the production of fine wool, rather than simply the amount of wool. The increased demand for finer wool and the associated price difference resulted in the proportion of fine wool (20 µm and finer) in the national clip to increase to 9.71% in 1998/99 (Olivier et al., 2002).

 

This shift in the emphasis of wool production led to more attention being paid to the production of fine wool types and the establishment of fine wool projects at the Cradock Experimental Station and at Grootfontein Agricultural Development Institute. Likewise, more producers in South Africa included decreased fibre diameter as one of the main breeding objectives in their selection programs (Olivier & Olivier, 2005). It is noteworthy that most of these flocks are kept under extensive farming conditions in the semi-arid and arid regions of South Africa where seasonal droughts regularly occur, subjecting these animals to nutritional stress. The general opinion was, however, that fine wool could not be effectively produced under the extensive and arid farming conditions of South Africa.

 

This resulted in a project at Grootfontein Agricultural Development Institute whereby genetically fine wool animals were evaluated under veld conditions from 1989 to 1999. As the farming and grazing conditions at Grootfontein is not representative of the RSA it limits the extrapolation of results from this study to the extensive sheep farming areas of South Africa (Olivier & Roux, 2006). A further project was therefore carried out to evaluate genetic fine wool animals under natural grazing conditions in the RSA.

 

MATERIAL AND METHODS

The project was conducted on the farms of four Merino producers in the non-traditional fine wool producing areas of South Africa. The participants were located in the Carnarvon, De Aar, Steynsburg and Wakkerstroom districts. The grazing on the farms of the Carnarvon and De Aar participants is mainly Karoo shrub veld, while at Steynsburg and Wakkerstroom it is mainly grass veld. In August 2000, 200 ewes of the Grootfontein fine wool flock (Olivier & Roux, 2006) were randomly divided into four groups and were collected by the participants between August and September 2000. These ewes were mated in May 2000 to rams from the Cradock fine wool Merino stud (Olivier et al., 2006). A group of each participant’s own ewes was also mated at approximately the same time as the fine wool ewes. The first lambs were born during October / November 2000. Replacement ewes born in 1999 were obtained from the original flock at Grootfontein. Rams from the Cradock fine wool Merino stud were used as sires in the respective fine wool lines, while the ewes of the control lines were mated to the rams of the respective participants.

 

The following production traits were recorded on the progeny: weaning weight (WW), body weight at 14 months of age (BW), greasy fleece weight (GFW), clean fleece weight (CFW), mean fibre diameter (MFD), staple length (STPL), coefficient of variation (CV) and staple strength (SS). The following traits were subjectively assessed prior to shearing at performance testing age: wool quality (QUAL), evenness over the fleece (VAR), staple formation (STAP), conformation of the front quarter (FQRT) and overall body conformation (CONF). The subjective traits were assessed on a scale from 1 to 50, where a score of 1 to 10 was poor, 11 to 20 was below average, 21 to 30 was average, 31 to 40 was above average and 41 to 50 was excellent, except for yolk and hocks where 25 was the ideal score. Body weight at mating (MW), fleece weight, fleece traits and total weight of lambs weaned per ewe per year (TWW) were recorded annually for the adult ewes.

 

The profit per hectare for the progeny of the two groups at each locality was calculated for each 14-month old animal by using the model, as described by Herselman (2004).  The production costs and product prices of October 2006 were used for the calculations.

 

Least-squares means (LSM) and standard errors (± s.e.) for all the traits were obtained with the Proc GLM-procedure of SAS, and significance levels between the treatment and control groups of each flock were obtained with the PDIFF-option under the PROC GLM-procedure of SAS (Littell et al., 2002).  Only the effects that had a significant effect on a specific trait were included in the final model, except for flock, which needed to be included in all the models, regardless of the significance level in order to obtain the LSM for the respective flocks.

 

RESULTS AND DISCUSSION

Lambs

The production traits of all the lambs born from 2000 to 2004 are summarized in Table 1. It is evident from Table 1 that the WW of the control lambs at De Aar and Wakkerstroom, as well as the BW of the control rams at Carnarvon and De Aar, were higher (P<0.05) than their counterparts. These weights did not differ between the fine wool and control groups at the other localities. The fine wool lambs produced finer and shorter wool (P<0.05) than the respective control groups at all four localities. The control lambs at Carnarvon, De Aar and Wakkerstroom produced more wool (P<0.05) than the corresponding fine wool lambs. The fine wool groups at De Aar and Wakkerstroom had a lower CV than their corresponding control groups., while at Steynsburg the control group had the lowest CV. The fine wool lambs at Steynsburg had a better (P<0.05) staple strength than their counterparts. It is evident from Table 1 that the fine wool groups at Steynsburg and Wakkerstroom had a higher (P<0.05) profit per ha compared to their counterparts. The higher profit could largely be ascribed to the differences in mean fibre diameter

 

Table 1. Production data of the lambs at the four participating farmers

 

Carnarvon

De Aar

Steynsburg

Wakkerstroom

 

Fine

Control

Fine

Control

Fine

Control

Fine

Control

WW (kg)

27.51

± 1.12

27.04

± 1.14

30.41b

± 1.13

32.31b

± 1.13

31.76

± 1.15

32.03

± 1.15

26.90d

± 1,24

29.80d

± 1.25

BW (kg)

43.52a

± 1.14

44.80a

± 1.18

51.17b

± 1.18

53.24b

± 1.18

41.01

± 1.28

41.86

± 1.31

45.75

± 1.21

46.48

± 1.16

CFW (kg)

2.81a

± 0.12

3.33a

± 0.12

3.42b

± 0.12

4.46b

± 0.12

2.26

± 0.13

2.25

± 0.13

2.59d

± 0.12

3.28d

± 0.12

MFD (mm)

17.74a

± 0.22

19.10a

± 0.23

18.18b

± 0.23

21.29b

± 0.23

16.03c

± 0.25

17.54c

± 0.25

17.54d

± 0.23

18.91d

± 0.22

STPL (mm)

85.28a

± 2.48

94.61a

± 2.58

91.93b

± 2.57

102.69b

± 2.56

76.71c

± 2.80

85.86c

± 2.85

 87.69d

± 2.63

 96.62d

± 2.53

CV (%)

18.88

± 0.38

19.03

± 0.39

18.94b

± 0.39

20.65b

± 0.39

21.00c

± 0.43

20.00c

± 0.44

19.56d

± 0.40

20.38d

± 0.39

SS (N/Ktex)

40.05

± 1.60

41.28

± 1.66

46.06

± 1.65

45.65

± 1.65

51.40c

± 1.79

43.52c

± 1.81

34.90

± 1.72

33.27

± 1.65

Profit (R/ha)1

34.86

± 7.08

31.09

± 7.35

68.48

± 7.32

65.39

± 7.32

110.86c

± 7.98

96.55c

± 8.14

405.47d

± 7.50

375.60d

± 7.22

a,b,c,d - Values with the same superscript differed significantly (P<0.05), a = Carnarvon, b = De Aar, c = Steynsburg, d = Wakkerstroom

1 Carrying capacity at Carnarvon is 30 ha/large stock unit (LSU), De Aar 18 ha/LSU, Steynsburg 12 ha/LSU and Wakkerstroom 3ha/LSU

 

The subjectively assessed traits are presented in Table 2. It is evident from this table that the wool quality of all the groups tended to be above average. The control lambs at De Aar and Steynsburg had better (P<0.05) wool quality than their fine wool counterparts. The VAR score for all the groups were above average, i.e. the fleeces of these groups were more even than the average. At Carnarvon, De Aar and Wakkerstroom the fleeces of the fine wool groups were more even than that of the control groups. The fine wool groups at Carnarvon and De Aar had thinner (P<0.05) staples than their corresponding control groups, while at Steynsburg the fine wool groups had thicker (P<0.05) staples.

 

The control group animals had better (P<0.05) hocks at all four localities than the fine wool groups and the only significant difference in pasterns was observed at Wakkerstroom, where the control animals had a higher score. The FQRT and CONF scores of the groups were average and the control animals had higher (P<0.05) scores for both these traits than the fine wool groups.

 

Table 2. Subjectively assessed traits of the lambs at the four participating farmers

 

Carnarvon

De Aar

Steynsburg

Wakkerstroom

 

Fine

Control

Fine

Control

Fine

Control

Fine

Control

QUAL

29.66

± 1.48

30.91

± 1.53

31.95b

± 1.52

34.35b

± 1.52

31.66c

± 1.62

34.79c

± 1.65

29.22

± 1.55

30.14

± 1.50

VAR

35.03a

± 1.25

31.12a

± 1.29

37.37b

± 1.28

31.02b

± 1.28

37.47

± 1.37

36.32

± 1.39

32.94d

± 1.31

30.33d

± 1,27

STAP

29.75a

± 0.92

30.71a

± 0.95

27.58b

± 0.94

32.98b

± 0.94

33.81c

± 1.01

31.46c

± 1.02

27.80

± 0.96

28.05

± 0.93

FQRT

22.83a

± 0.98

24.51a

± 1.01

23.93b

± 1.01

26.65b

± 1.01

26.00c

± 1.08

28.26c

± 1.09

22.79d

± 1.03

25.26d

± 1.00

CONF

24.40a

± 1.15

27.69a

± 1.18

25.85b

± 1.17

29.67b

± 1.17

28.95c

± 1.25

31.86c

± 1.27

23.35d

± 1.20

26.49d

± 1.16

a,b,c,d - Values with the same superscript differed significantly (P<0.05), a = Carnarvon, b = De Aar, c = Steynsburg, d = Wakkerstroom

 

Ewe flock

The production and reproduction data of the adult ewes from 2000 to 2004 at all four localities are summarized in Table 3. It is evident from this table that the fine wool ewes at Carnarvon and Steynsburg were heavier (P<0.05) than the control ewes at mating, while at De Aar and Wakkerstroom the control ewes were heavier (P<0.05) than the fine wool ewes.

 

Table 3. The wool production and reproduction data of the adult ewes at the four participating farmers

 

Carnarvon

De Aar

Steynsburg

Wakkerstroom

 

Fine wool

Control

Fine wool

Control

Fine wool

Control

Fine wool

Control

MW (kg)

47.09a

± 0.41

45.77a

± 0.42

52.56b

± 0.43

53.68b

± 0.42

51.51c

± 0.59

46.85c

± 0.59

52.25d

± 0.40

54.13d

± 0.39

CFW (kg)

3.06

± 0.05

3.13

± 0.05

3.41b

± 0.05

4.47b

± 0.05

3.49c

± 0.07

3.04c

± 0.07

3.37d

± 0.05

3.96d

± 0.05

MFD (mm)

19.45a

± 0.11

21.24a

± 0.11

20.03b

±0.11

23.99b

± 0.11

19.65c

± 0.16

20.95c

± 0.17

19.21d

± 0.11

21.74d

± 0.11

STPL (mm)

89.39

± 0.84

91.63

± 0.86

88.65b

± 0.86

96.31b

± 0.85

79.18c

± 1.24

89.06c

± 1.31

91.70d

± 0.82

97.46d

± 0.82

CV (%)

17.99a

± 0.13

19.04a

± 0.13

18.60b

± 0.13

19.89b

± 0.13

17.99

± 0.19

17.73

± 0.20

18.53d

± 0.13

19.58d

± 0.13

SS (N/Ktex)

44.87

± 0.93

45.67

± 0.94

43.99b

± 1.14

38.52b

± 1.13

43.47

± 1.40

45.75

± 2.03

49.63

± 1.11

51.41

± 1.12

TWW (kg/ewe/year)1

27.72

± 1.00

25.65

± 1.02

27.26

± 1.04

30.00

± 1.02

26.39

± 1.13

25.46

± 1.11

23.31

± 1.12

23.84

± 1.11

a,b,c,d - Values with the same superscript differed significantly (P<0.05), a = Carnarvon, b = De Aar, c = Steynsburg, d = Wakkerstroom

1 Weaning weight corrected to 120 days and sex, except at Wakkerstroom where weaning weight was corrected to 180 days

 

The fine wool ewes at De Aar and Wakkerstroom produced less wool (P<0.05) than their counterparts, whereas the fine wool ewes at Steynsburg produced more wool (P<0.05) than their counterparts. The fine wool ewes at all four localities were finer (P<0.05) than their counterparts. At three of the localities the staple length of the fine wool ewes was shorter (P<0.05) than that of the control ewes, except at Carnarvon where there was no differences. There were no significant differences observed between the total weight of lamb weaned per ewe per lambing opportunity of the two lines.

 

CONCLUSION

It is evident from the results of this project that the fine wool animals produced less and finer wool compared to the control animals. This was expected, as these traits are positively correlated. However, the most important conclusion is that the reproduction and body weight of the fine wool animals were in the same range as that of the control animals. The differences in mutton production between these groups were relatively small and would therefore not have a major effect on the profitability of a fine wool versus strong wool sheep farming enterprise.

 

ACKNOWLEDGEMENTS

The authors want to express their gratitude to Cape Wools of South Africa for funding the project, officials from the NWGA, BKB and CMW for assisting in the execution of the project and the four participating farmers for their contribution to the success of the project.

 

REFERENCES

Herselman, M.J., 2004. Description of a model for the calculation of breeding values for profitability. Proc. 40TH SASAS Cong.. 101.

Littell, R.C., Freud, R.J. & Struop, W.W., 2002. SAS-system for linear models, 4th Ed. SAS Institute. Inc. Cary, N.C., USA.

Marx, F.E., 1981. Die gehalte van die Suid-Afrikaanse Merinoskeersel oor dertig jaar.  Karoo Agric. 2(1):13-14.

Olivier, W.J., Olivier JJ, Snyman MA, Pretorius AP & Van Heerden M, 2002. Production and reproduction norms of fine woolled Merino sheep on natural pastures in the Karoo. Grootfontein Agric., 5: 29-31.

Olivier, W.J. & Olivier, J.J., 2005. Effect of feeding stress on the wool production of strong and fine wool Merino sheep. S. Afr . J. Anim. Sci. 35 (4), 273-281.

Olivier, W.J. & Roux, J.A., 2006. Production and reproduction norms of fine woolled Merino sheep on natural pastures in the Karoo. S. Afr . J. Anim. Sci. Submitted.


 

Published

Karoo Agric 7 (1)