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EVALUATION OF A GENETICALLY FINE MOHAIR ANGORA GOAT FLOCK

 

M. A. Snyman & P. J. Griessel

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

 

 

1.  Introduction

During 1999, South Africa produced 62 % of the world production of 7.2 million kg mohair. Taking into account the decline in world mohair production, and the large proportion of total world mohair production produced in South Africa, it is essential that the quality of the clip, especially in terms of fineness, be maintained in order to qualify as a speciality fibre. Fibre diameter is of critical importance in determining the eventual textile qualities and final manufacturing applications of mohair.

After the exceptionally high prices paid for mohair in South Africa during the mid 1980's, the mohair clip was getting stronger, due to virtually every mohair producing animal being kept by the farmers. There was a concern amongst leaders in the mohair industry that the world renowned quality of the South African clip might be in danger of deteriorating. The Grootfontein Agricultural Development Institute was requested to investigate the possibility of establishing a genetically fine mohair flock in South Africa. One of the perceptions which existed in the mohair industry at that stage, was that it was impossible to breed a genetically fine mohair goat which was not a small, unthrifty goat and, which conformed to the breed standards set for South African Angora goats. A project which involved the establishment and evaluation of a genetically fine mohair flock was subsequently initiated at the Angora Goat Experimental Station near Jansenville in the Eastern Cape Province of South Africa in 1988. In this paper, the productive performance of the established fine hair flock is compared with that of a control flock which was run together with the fine hair flock for the duration of the project.

 

2.  Material and Methods

2.1 Establishment of the fine mohair flock

From 1988 till 1992, Angora ewes were bought from Angora goat stud breeders and commercial flock farmers to form the basis for a fine hair flock. Since April 1991, the fine hair flock size was kept at approximately 150 ewes. To date, 14 stud rams, 12 commercial flock rams, as well as 31 rams bred in the flock itself, were used as sires in the fine hair flock. The fine hair flock is managed together with a control flock of 100 ewes, which are representative of the average Angora goat in South Africa.

 

2.2  Description of the experimental location

The project was carried out at the Angora Goat Experimental Station (32E 58' S, 24E 41' E) near Jansenville in the Eastern Cape Province of South Africa. The veld type at the Experimental Station consists of noors- and succulent mountainous veld (Veld 24, Acocks, 1988). Jansenville has a mean annual temperature of 19EC, the mean minimum and maximum temperatures being 11.5EC and 26.5EC respectively. The area is largely frost-free. The average long term annual rainfall is 264 mm.

 

2.3  Management practices and data recorded

The ewes were mated during April each year. An individual mating system was followed, where each ram was run in a small camp together with his allocated number of ewes for a 35 day mating period. During 1993 to 1998, ewes in the fine hair flock were artificially inseminated, due to a shortage of genetically fine hair rams. During the 1995 and 1996 mating seasons, all ewes of the control flock were also artificially inseminated with fresh semen from fine hair rams, in an effort to increase the genetic basis of, and number of offspring available for selection purposes in the fine hair flock. Since 1997, the control ewes have again been mated to control rams. Therefore, there were no data available on control flock kids for 1995 and 1996.

During kidding in September, the following data were recorded for each kid : Kid ID, Dam ID, Sire ID, date of birth, birth weight, sex and birth status of the kid. Body weight at 42 days and weaning weight at 120 days of age were also recorded. Thereafter, kids were weighed monthly.

Due to the thorny nature of the Noorsveld, all ewes and rams were shorn three times a year during March, July and November. Kids were shorn at five months of age for the first time (February), then at 10 (July), 14 (November) and 18 (March) months of age. During each shearing a midrib fleece sample (50 g) was taken for analysis of fibre diameter, clean yield and staple length. Fibre diameter was measured using the air-flow method. Body weight and fleece weight were determined just after shearing of each goat.

Before the second, third and fourth shearings, fleece traits of all kids were subjectively assessed on a linear scale ranging from one to 50. Prior to the second and third shearings, fleece samples were taken on three positions on the back line (between the withers, in the lumbar region and posterior to the tail) of each kid. These samples were mixed for each kid and used for objective measurement of kemp and medullated fibres with a projection microscope.

 

2.4  Replacement procedures in the fine hair and control flocks

During the early years of the project, very little selection on actual performance traits was done in the fine hair flock, due to the fact that the ewe numbers in the flock needed to be increased. Since 1996, however, selection of young replacement rams and ewes was based on the following selection index (SI), which has as its aim to increase body weight, decrease fibre diameter and maintain fleece weight (Snyman et al., 1996) :

            SI = (13 x Body weight) + (4 x Fleece weight) - (23 x Fibre diameter)

The body weight, fleece weight and fibre diameter measured at the third shearing at 14 months of age were used in the selection index.

After the ewe flock numbers were stabilized, 20 % of the ewes were replaced with young ewes each year. Mature ewes were culled on condition of their teeth and udder abnormalities. Ewes which failed to reproduce for three years were also culled. Selection of young replacement ewes and rams took place at 18 months of age just before their fourth shearing. Visual appraisal of fleece traits was done, and goats with cull faults according to breed standard or with conformation abnormalities were culled. Final selection was done on the basis of the above mentioned selection index, in combination with independent culling levels for percentage kemp and medullated fibres measured at 10 and 14 months of age.

Replacements in the control flock were done according to the procedures described by Erasmus & Heydenrych (1984) for the maintenance of a genetic control flock. All rams and 20 % of the ewes were replaced with young goats each year. Where possible, each ram or ewe were replaced by one of his sons or her daughters.

 

2.5   Statistical analysis

2.5.1   Kid data

Data from kids born from 1989 to 1998 in the fine hair (n=1120) and control (n=710) flocks were available. For the purpose of evaluating the established fine hair flock against the control flock, only data from kids born from 1994 till 1998 were used. Least‑squares means for the various traits were obtained from the least‑squares mean method analyses of Harvey (1990). The PDIFF-option under the PROC GLM-procedure of SAS (Littell et al., 1991) was used to obtain levels of significance between fine hair and control flock ram and ewe kids.

 

2.5.2  Ewe data

Data collected on the ewe flock from 1988 to 1999 were available, but for the purpose of this study, only data from ewes present in the flocks from 1993 till 1999 were included for analysis. Before analysis, the data were edited as follows : Total fleece weight produced per year was calculated by adding the fleece weight of the March, July and November shearings of each year for each ewe. The average performance in terms of body weight, fibre diameter, clean yield percentage and staple length was  calculated by averaging all measurements recorded for each ewe for each year. Clean fleece weight per year was calculated by multiplying the total fleece weight with the average clean yield percentage for each ewe. Data of the ewes were analysed by means of least‑squares mean methods (Harvey, 1990). For the analyses of variance for all traits mentioned above, fixed effects for flock, year and age of the ewe were included in the models.

 

2.5.3   Reproduction data

Reproduction data collected on the ewe flock from 1988 to 1999 include number of ewes mated, number of ewes kidded, number of kids born, number of still born kids and number of kids weaned, as well as total weight of kids weaned per ewe per year (kg). A total of 1395 and 1052 individual ewe reproductive records were available for the fine hair and control flock ewes respectively. These comprised records from 419 fine hair and 301 control flock ewes.

 

3.  Results

3.1  Body weight and fleece traits of kids and young goats

Least‑squares means for birth weight, weaning weight, body weight and fibre diameter at 5 and 10 months of age and body weight and fleece traits at 14 and 18 months of age are summarised in Table 1 for the fine hair and control flock ram and ewe kids respectively.

 

Table 1. Body weight and fleece traits (SE) of fine hair and control flock kids from birth till 18 months of age

 

 Trait

Ewes

Rams

Fine hair

Control

Fine hair

Control

Birth weight (kg)

2.74 (0.13) a

2.89 (0.14) a

2.99 (0.12)

3.02 (0.14)

Weaning weight (kg)

14.59 (0.19) a

13.61 (0.40) a

16.68 (0.18) b

15.71 (0.38) b

5m. Body weight (kg)

15.58 (0.21) a

14.63 (0.43) a

17.68 (0.20) bb

16.42 (0.42) bb

5m. Fibre diameter (Fm)

23.22 (0.10) aa

24.13 (0.20) aa

23.51 (0.09) bb

24.54 (0.19) bb

10m. Body weight (kg)

17.62 (0.25) aa

16.24 (0.49) aa

20.36 (0.23) bb

18.77 (0.51) bb

10m. Fibre diameter (Fm)

24.50 (0.14) aa

25.93 (0.27) aa

24.45 (0.12) b

25.11 (0.27) b

14m. Body weight (kg)

20.87 (0.29) a

19.54 (0.59) a

24.13 (0.27) bb

21.22 (0.62) bb

14m. Fleece weight (kg)

0.92 (0.01) aa

1.02 (0.02) aa

0.91 (0.01) bb

1.02 (0.02) bb

14m. Clean yield (%)

77.47 (0.48) aa

68.60 (0.97) aa

76.11 (0.44)

75.91 (1.01)

14m. Clean fleece weight (kg)

0.71 (0.01)

0.72 (0.02)

0.69 (0.01) bb

0.77 (0.02) bb

14m. Fibre diameter (Fm)

26.06 (0.16) aa

28.37 (0.33) aa

25.61 (0.15) bb

27.08 (0.34) bb

14m. Staple length (cm)

10.65 (0.07)

10.63 (0.13)

10.49 (0.06)

10.50 (0.14)

18m. Body weight (kg)

24.89 (0.32)

23.58 (0.66)

30.29 (0.30) bb

26.53 (0.62) bb

18m. Fleece weight (kg)

1.40 (0.02) aa

1.54 (0.03) aa

1.58 (0.02)

1.62 (0.03)

18m. Clean yield (%)

75.65 (0.30)

76.77 (0.61)

74.53 (0.28)

74.09 (0.58)

18m. Clean fleece weight (kg)

1.05 (0.01) aa

1.18 (0.03) aa

1.18 (0.01)

1.20 (0.02)

18m. Fibre diameter (Fm)

31.13 (0.16) aa

33.34 (0.33) aa

31.13 (0.15) b

31.88 (0.32) b

18m. Staple length (cm)

9.99 (0.09) a

9.58 (0.18) a

10.30 (0.08) b

 9.87 (0.17) b

 a, b      = Values with the same superscripts within the same sex, differ significantly (P<0.05)

 aabb = Values with the same superscripts within the same sex, differ significantly (P<0.01)

 

Birth weight of control flock ewe kids was 0.15 kg heavier (P<0.01) than that of the fine hair ewe kids. However, from weaning till 18 months of age, fine hair ewe kids were heavier than the control flock ewe kids. There was no significant difference in birth weight between the control flock and fine hair ram kids. Recorded body weights of fine hair rams were heavier than those for control flock rams at weaning (P<0.05), 5, 10, 14 and 18 (P<0.01) months of age.

Fibre diameter of the fine hair kids was finer than that recorded for the control flock kids at all ages, the difference being larger for the ewe than the ram kids. Fine hair ewe and ram kids produced hair that was respectively 2.31 Fm and 1.47 Fm finer than that produced by control flock kids at 14 months of age. These differences were 2.21 Fm and 0.75 Fm at 18 months of age.

Fleece weight of the fine hair kids was lower than that produced by the control flock kids (P<0.01), except for the rams at 18 months of age, where no difference in fleece weight was recorded. The difference in fleece weight was 0.10 kg and 0.11 kg less at 14 months of age for fine hair ewe and rams kids respectively, compared to the corresponding fleece weight produced by the control flock kids. The corresponding difference for the ewes at the 18 month shearing was 0.14 kg.

There was no difference in clean yield percentage between control flock and fine hair ram kids at 14 or 18 months of age, while clean yield percentage of fine hair ewe kids at 14 months of age was 9 % higher than the corresponding value for the control flock kids. Staple length did not differ between fine hair and control flock ewe kids at 14 months of age, but the fine hair kids produced longer staples (P<0.05) than their control flock contemporaries at 18 months of age.

 

3.2  Subjective fleece and conformation traits of young goats

Least‑squares means for the various subjective fleece and conformation traits assessed at 18 months of age are summarised in Table 2 for the fine hair and control flock ram and ewe young goats respectively.

 

Table 2. Subjective fleece and conformation traits (SE) of fine hair and control flock young goats assessed at 18 months of age

 Trait

Ewes

Rams

Fine hair

Control flock

Fine hair

Control flock

Head and horns

32.23 (0.29)

31.70 (0.60)

33.76 (0.28)

33.73 (0.62)

Pigmentation

32.74 (0.38) a

30.57 (0.77) a

31.80 (0.36)

30.22 (0.81)

Face cover

31.17 (0.42)

31.44 (0.86)

32.21 (0.40)

31.52 (0.90)

Neck cover

29.96 (0.33)

30.91 (0.67)

30.99 (0.31)

31.01 (0.70)

Softness of face

39.52 (0.29) a

38.16 (0.59) a

38.43 (0.28)

37.17 (0.62)

Softness of fleece

33.28 (0.35) aa

27.83 (0.72) aa

33.59 (0.33) bb

31.01 (0.75) bb

Style

30.85 (0.34) aa

26.13 (0.69) aa

30.57 (0.32) b

29.06 (0.73) b

Character

24.05 (0.30) a

22.52 (0.62) a

23.86 (0.29)

24.08 (0.65)

Evenness of fleece

35.98 (0.30) aa

32.70 (0.62) aa

38.30 (0.29) bb

34.24 (0.65) bb

Density of fleece

32.39 (0.26)

32.16 (0.53)

31.86 (0.25)

32.50 (0.56)

Yolk

23.59 (0.25)

24.01 (0.51)

23.19 (0.24)

23.27 (0.53)

Bellies and Points

32.89 (0.31)

32.07 (0.64)

33.16 (0.30) bb

30.56 (0.68) bb

Kemp score

40.24 (0.28)

41.06 (0.56)

41.13 (0.26)

40.65 (0.59)

% Kemp & medullated fibres

 

0.35 (0.03)

 

0.32 (0.06)

 

0.28 (0.03)

 

0.33 (0.06)

 a, b      = Values with the same superscripts within the same sex, differ significantly (P<0.05)

 aabb = Values with the same superscripts within the same sex, differ significantly (P<0.01)

Head and horns, face cover, neck cover and softness of face did not differ between fine hair and control flock goats. There was also no difference in pigmentation between fine hair and control flock rams, while the fine hair ewes had more pigment than their control flock counterparts. The fine hair goats had softer fleeces than the control flock goats, which is a reflection of the lower fibre diameter. Fine hair ewes had better style of the fleece and more ideal character of the fleece than control flock ewes, which had less style and straighter hair. Fine hair rams tended to produce hair with better style, compared to the control flock rams. Evenness of fleece in terms of variation in fibre diameter, staple length, style and character from the neck to the britches, was better (P<0.01) in the fine hair goats than in the control flock goats.

There were no differences in density of the fleece, fullness of bellies and points or the amount of yolk in the fleece between fine hair and control flock goats, with the exception of fine hair rams having better bellies and points (P<0.01) than the control flock rams. Furthermore, there were no differences between fine hair and control flock kids in terms of subjective kemp score and percentage kemp and medullated fibres in the fleece.

From Table 2 it is evident that above average scores were given for all conformation and fleece traits for both fine hair and control flock goats, with the exception of character and yolk which got ideal scores. According to these results, the fine hair animals conform to the breed standards set for South African Angora goats.

 

3.3  Body weight and fleece traits of the ewe flock

Least‑squares means for body weight and fleece traits of the fine hair and control flock  ewes are summarised in Table 3.

 

Table 3. Body weight and fleece traits (SE) of fine hair and control flock ewes

Trait

Fine hair ewes

(n=1576)

Control ewes

(n=1124)

Body weight (kg)

35.57 (0.15)

35.83 (0.15)

Fleece weight (kg/year)

3.55 (0.02) aa

3.91 (0.03) aa

Clean yield (%)

77.52 (0.10) aa

78.13 (0.13) aa

Clean fleece weight (kg/year)

2.74 (0.02) aa

3.03 (0.02) aa

Fibre diameter (Fm)

34.39 (0.08) aa

36.94 (0.09) aa

Staple length (cm / 4 month clip)

10.32 (0.03) aa

10.61 (0.04) aa

 aa  =  Values with the same superscripts within the same row, differ significantly (P<0.01)

 

There was no significant difference in body weight between ewes in the fine hair and control flocks. Fine hair ewes produced 0.36 kg less hair per year, which was 2.55 Fm finer than the hair produced by the control flock ewes. Clean yield percentage of control flock ewes was 0.61 % higher and their hair was 0.29 cm longer than the hair produced by the fine hair ewes.

 

3.4  Reproductive performance of the ewe flock

Least‑squares means for the various reproductive traits of the fine hair and control flock  ewes are summarised in Table 4.

 

Table 4. Reproductive performance of fine hair and control flock ewes

Trait

Fine hair ewes

(n=419 ewes)

(n = 1395 records)

Control ewes

(n=301 ewes)

(n = 1052 records)

% Ewes kidded / ewes mated

75.05 % a

78.71 % a

% Kids born / ewe kidding

117.10 % aa

127.22 % aa

% Kids born / ewe  mated

87.86 % aa

100.30 % aa

% Still born kids

6.20 %

5.03 %

Kid survival rate

84.96 %

83.00 %

% Kids weaned / ewes mated

70.04 % aa

78.81 % aa

Total weight of kids weaned/ewe/year (kg)

13.46 (0.43)

14.18 (0.34)

 a, aa     = Values with the same superscripts within the same row, differ significantly;  a = (P<0.05);  aa = (P<0.01)

 

The percentage of ewes that kidded per number of ewes that was mated, was 75.05 % and 78.71 % for the fine hair and control flocks respectively. Control flock ewes produced more kids (P<0.01) per ewe that was mated (100.30 % vs. 87.86 %) or eventually kidded (127.22 % vs. 117.10 %) than fine hair ewes. The weaning percentage, in terms of kids weaned per number of ewes mated, was 8.77 % in favour of the control flock ewes. There were no differences between the two flocks in the percentage of still born kids, the kid survival rate or the total weight of kids weaned per ewe per year.

Unfortunately, reliable conclusions as to the relative reproductive performance of the fine hair and control flock ewes could not be drawn, due to the fact that the data are not comparable, as the fine hair ewes were artificially inseminated from 1993 to 1998.

 

4.   Discussion

Fleece traits which contribute to the economic value of mohair, are fibre diameter, staple length, style and character and evenness of fleece. Of these, fibre diameter has the overriding influence on price, as is evident from the price difference between kid hair, young goat hair, fine adult hair and strong adult hair. For mohair with the same fibre diameter, the traits staple length and then style and character, have the biggest influence on price (Geyer, 1987). According to a study done by Hunter et al. (1997), superior style and character had a significant beneficial effect on the textile performance of mohair, and it is therefore justified to ascribe a greater value to mohair possessing superior style and character. For all the traits mentioned here, the fine hair goats performed better than the control flock goats.

During the classing process, the neck and britches are removed and classed separately, because they differ in fibre diameter and length from the rest of the fleece (Van der Westhuizen et al., 1988). Lower prices are also obtained for these lines. The importance of evenness of fleece lies therein that a much smaller proportion of the fleece would go into the neck or britches lines, and a larger proportion into the more expensive fleece lines. The fine hair goats had an advantage over the control flock goats with regard to better evenness of fleece (Table 2).

The decline in fleece weight in the fine hair flock could be regarded as the only negative outcome of this study. The higher prices obtained for the finer hair, would however, offset this disadvantage of the fine hair ewes. Since 1998, more emphasis was placed on fleece weight in the selection of fine hair sires.

Results from this project have been passed on to the mohair industry on a continuous basis throughout the duration of the project. Already the general trend in the industry is towards breeding finer haired animals, as is evident from the selection objectives of most of the Angora ram breeders (Snyman et al., 1996). The South Africa clip comprised of 17 % kid hair, 19 % young goat hair, 19 % fine adult hair and 45 % strong adult hair during 1999 (Anon, 1999). This indicates a shift towards finer hair, when compared to the 53 % strong adult hair produced in 1985 (Anon, 1985). The positive results obtained with this project contributed to this shift in the industry towards a finer mohair clip. Genetic parameters estimated for the various body weight and fleece traits for South African Angora goats indicate that selection for lower fibre diameter, while increasing body weight and increasing or maintaining the other economic important fleece traits, is viable (Snyman & Olivier, 1996, 1998).

 

5.   Conclusion

The results of the study proved that it is possible to breed a genetically fine haired Angora goat which conforms to the standards of excellence laid down for South African Angora goats. Apart from the fact that the fine hair ewes did not have a lower body weight than the control flock ewes, they produced finer fleeces which had better style and character, and were more even than those produced by the control flock ewes. In a selection programme aimed at decreasing fibre diameter in Angora goats, fleece weight should also be monitored.

 

6.   References

ACOCKS, J.P.H., 1988. Veld types of South Africa. 3rd.Ed, Botanical Research Institute, Dept. of Agric. and Water Supply

ANONYMOUS, 1985. Twentieth Yearly Report of the Mohair Board

ANONYMOUS, 1999. Review 1999. Mohair South Africa

ERASMUS, G.J. & HEYDENRYCH, H.J., 1984.  Die gebruik van genetiese kontrolekuddes in diereteling. Karoo Agric 3(3), 7-11

GEYER, A.C., 1987. Die relatiewe ekonomiese belangrikheid van sekere eienskappe van sybokhaar met spesifieke verwysing na jongbokhaar. M.Sc - thesis, University of the Orange Free State, Bloemfontein, South Africa

HARVEY, W.R., 1990. Mixed Model Least‑Squares and Maximum Likelihood Computer Program. Walter R Harvey

HUNTER, L, SMUTS, S. & DORFLING, L., 1997. The influence of style and character on the textile performance of Cape Mohair. Angora Goat and Mohair Journal, 39(1) : 47-51

LITTELL, R.C., FREUD, R.J. & SPECTOR, P.C., 1991. SAS-system for linear models, 3rd Ed. SAS Institute. Inc. Cary, NC

SNYMAN, M.A. & OLIVIER, J.J., 1996. Genetic parameters for body weight, fleece weight and fibre diameter in South African Angora goats.  Livest. Prod. Sci., 47(1) : 1-6

SNYMAN, M.A. & OLIVIER, J.J., 1998. Repeatability of objective and subjective fleece traits and body weight in South African Angora goats. Small Rum. Res. 34(2) : 103-109

SNYMAN, M.A., OLIVIER, J.J. & WENTZEL, D., 1996. Breeding plans for South African Angora goats. Angora Goat and Mohair Journal, 38(1) : 23-31

VAN DER WESTHUIZEN, J.M., WENTZEL, D. & GROBLER, M.C., 1988. Angora goats and Mohair in South Africa. NMB Printers, Port Elizabeth, South Africa

 

Published

Proceedings 33rd SASAS congress, Warmbad, 28-31 March