Last update: December 6, 2010 02:15:25 PM E-mail Print

 

EVALUATION OF THE GENETIC POTENTIAL FOR GROWTH AND WOOL PRODUCTION OF SHEEP

IN THE COMMUNAL AREAS OF THE EASTERN CAPE



P.G. Marais, B.R. King & C.G. Stannard


Grootfontein Agricultural Development Institute, Private Bag X529, Middelburg (EC), 5900

 


INTRODUCTION

This project forms part of a larger livestock improvement project for woolled sheep development in the communal areas of the Eastern Cape. It entails the provision of 3000 commercially bred rams annually by the National Wool Growers’ Association (NWGA) to these farmers. The aim of this project was to evaluate the impact of these rams on the production potential of the wool sheep in the communal areas. This project was done in two phases, namely, 1) to evaluate the progeny from communal and commercial bred rams under commercial conditions and 2) evaluation of the progeny of commercial and communal bred rams on communal ewes under communal conditions.

 

MATERIAL AND METHODS

The project commenced in March 2004 at four localities in the Tarkastad and Cathcart districts. With the exception of one farmer, the rest were all suppliers of rams to the NWGA livestock improvement project. At the start of the project, at each farm a flock of 200 ewes was randomly divided into two groups and each group was individually tagged and numbered. One group of 100 ewes was mated to six commercial bred rams and the other 100 ewes to six communal rams. The groups were placed in different camps, comparable in size and veld quality and quantity, for a 6-week mating period. After mating, the groups were run together as one flock.

 

Four communal areas were selected on the basis that they were representative of the average farming conditions in this region. The four participating communities were Ncorga Inagatu Irrigation Scheme (Umgababa Community, Ngcobo), Quatsa New Mines Community (Mbheku shearing shed, Tsomo), Sokapasa Community (Nqamakwe) and Singinquni Community (Kentani). A number of ewes were randomly chosen in each community, divided into two groups and each group was individually tagged and numbered with different colour ear tags. One group of ewes was mated to six commercial (breeding project) rams and the other group to six communal rams. Shepherds kept the groups separate for the mating period. After mating, the ewes were allowed to return to their respective owners. Ewes lambed from the middle of March 2005 and lambs were tagged in each community on a weekly basis. Statistical analysis was performed by using the GLM procedures of SAS (Littell et al., 1991).

 

RESULTS AND DISCUSSION

The average weaning and 6-month weight of the progeny born from commercial ewes mated to commercial and communal rams are summarised in Table 1.

 

Table 1. Weaning and 6-month weight (±s.e.) of the progeny born from commercial vs. communal rams on commercial ewes 

Weight (kg)

Commercial

Communal

Ewes

Rams

Overall

Ewes

Rams

Overall

Weaning

22.6±0.2

23.7±0.2

23.2a±0.2

21.4±0.2

22.5±0.2

21.9b±0.2

6 months

29.4±0.2

32.3±0.2

30.2a±0.3

27.8±0.2

30.3±0.2

28.62b±0.2

a,b values in the same row with different superscript differ significantly (P<0.05)

 

The weaning and 6-month body weight of the progeny from commercial rams was significantly higher than that of communal rams.

 

The average weaning, 7-month and 14-month weight of the progeny born from communal ewes mated to commercial and communal rams are summarised in Table 2.

 

Table 2. Average body weight (±s.e.) of the progeny born from commercial vs. communal rams on communal ewes 

Weight (kg)

Commercial

Communal

Ewes

Rams

Overall

Ewes

Rams

Overall

Weaning

10.9±0.3

12.1±0.5

11.5±0.4

10.5±0.2

11.5±0.3

11.0±0.3

7 months

16.5±0.5

19.1±0.8

17.8±0.8

14.3±0.2

18.9±0.8

16.6±0.7

14 months

23.2±0.5

27.6±0.4

25.4±0.4

22.5±0.4

27.3±0.3

25.0±0.3

 

 

 

No significant differences in the weaning weight, 7-month weight and 14-month weight between the progeny of the two mating groups could be detected. Due to the fact that the trial at the commercial farmers was terminated when the offspring reached the age of 6 months, all the lambs were shorn. The respective wool traits at 6 months of age of the offspring of ewes mated with commercial and communal rams at the four commercial localities are summarised in Table 3.

 

Table 3. Wool traits (±s.e.) of the progeny of commercial ewes mated with commercial vs. communal rams

Traits

Commercial

Communal

Greasy fleece weight (kg)

Fibre diameter (µm)

Coefficient of variation (%)

Standard deviation (µm)

Comfort factor (%)

Clean yield  (%)

Clean fleece weight (kg)

Clean wool price (R/kg)

Clean wool income (R/Sheep)

2.8a±0.1

18.4a±0.1

19.8±0.2

3.7a±0.1

99.4a±0.1

76.3a±0.3

2.14a±0.2

43.38±1.0

92.67a±0.2

2.4b±0.3

20.0b±0.1

20.7±0.2

4.1b±0.1

98.2b±0.1

68.5b±0.3

1.64b±0.1

36.55±0.9

60.09b±0.1

a, b values in the same row with different superscript differ significantly (P<0.05)

 

With reference to the different wool traits of the progeny of the two groups at the commercial farms, it is evident that differences did occur (Table 3). The average greasy fleece weight of the progeny at 6 months of age differed significantly between the commercial group (2.8 kg) and that of the communal group (2.4 kg). The average wool traits (fibre diameter, standard deviation, comfort factor, clean yield and clean fleece weight) of the commercial ram group were better (P<0.05) than that of the communal group. The clean wool price of each group was obtained from the auction catalogue price of the specific wool type. The average clean wool income (R/sheep) of commercial bred progeny (R92.67) was significantly higher than that of the communal progeny (R60.09).

 

At 3 months of age all the lambs in the communal trial were shorn. After 12 months of wool growth (15 months of age), these lambs were again shorn for comparisons between ram breeding groups. The respective wool traits of the offspring of ewes mated with commercial and communal rams at the four different localities are summarised in Table 4.

 

The greasy fleece weight of the progeny from the commercial group (2.0 kg) was significantly higher than the communal group (1.7 kg). With the exception of clean yield, the other wool traits did not differ significantly between the groups. The clean wool price of each group per community was obtained from the auction catalogue price of the specific wool type. The average clean wool income (R/sheep) of the commercial bred progeny (R54.87) was significantly higher than that of the communal bred progeny (R37.53).

 

Table 4. Wool traits (±s.e.) of the progeny of communal ewes mated with commercial vs. communal rams

Traits

Commercial

Communal

Greasy fleece weight (kg)

Fibre diameter (µm)

Coefficient of variation (%)

Standard deviation (µm)

Comfort factor (%)

Clean yield  (%)

Clean fleece weight

Clean wool price (R/kg)

Clean wool income (R/sheep)

2.0a±0.1

19.4±0.2

22.0±0.7

4.3±0.2

98.5±0.5

66.9a±1.3

1.34a±0.1

41.01±1.0

54.87a±0.2

1.7b±0.1

20.5±0.2

23.4±0.5

4.8±0.1

96.7±0.3

60.5b±0.9

1.03b±0.2

36.49±0.7

37.53b±0.2

a, b values in the same row with different superscript differ significantly (P<0.05)

 

CONCLUSIONS

The results of this study suggest that the commercial rams have a higher growth potential compared to communal rams, but the general grazing conditions in the communal areas is a limiting factor in realising it. By introducing commercial rams into the communities, greasy fleece weight as well as clean yield percentage increased significantly. The results further indicated that an improvement in the clean wool income of R17.34 per sheep was possible with the introduction of commercial rams in the communal areas.

 

REFERENCES

Littell, R.C., Freud, R.J. & Spector, P.C., 1991. SAS System for Linear Models. Third Edition. SAS Institute Inc. Cary, NC.

 

ACKNOWLEDGEMENTS

The following organisations supported / participated in the project:

Eastern Cape Department of Agriculture

National Wool Growers’ Association

Participating communities

Participating farmers

Agricultural Research Council: Livestock Business Division

BKB

 

Published

Grootfontein Agric 8 (1)