- Afrino Wool - Quo Vadis?
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Afrino Wool - Quo Vadis?
S.A.Fleece Testing Centre, A.D.S.R.I.
Wool is undoubtedly a unique fibre, but in order to maintain this indisputably unique status, the physical qualities of the fibre have to conform to certain standards, which firstly are to be defined and then implemented through breeding.
Social changes such as political and economical pressures as well as ethical viewpoints influencing selection objectives, determine the philosophy behind animal breeding (Land 1981) and therefore it is extremely dangerous for a geneticist to lay down a breeding policy. Lerner and Donald (1966) arrived at the conclusion that: "Animal genetics stands ready to help in reaching the objectives of society. It is for society to decide where its ambitions lie and what are its purposes." At their utmost, scientists can be directive in formulating a breeding policy by a meaningful evaluation and adaptation of information currently at their disposal, such as market trends, long-term tendencies, forecasts and biological and genetic knowledge on the breed.
Market directed production should be the main object in product supply and because of a relatively long generation interval with animals, causing a long period between "action" and "result" and accentuating the fact that the flexibility to change course quickly is very limited in animal breeding (Skjervold, 1984), the long-term trends influencing price tendencies should play a decisive role in laying down a breeding strategy in terms of wool production for the Afrino.
In 1950, wool comprised 11,9% of the world fibre production, as against a mere 5,396 in 1980 and it will decrease to a predicted 396 in the year 2 000 (Moolman, 1982). The decrease is the result of wool having to compete with other natural (cotton 45%; cellulose fibres 11,896; mohair 0,05%) and synthetic fibres (polyester 37,3%) while synthetic fibres have the advantage of continuous supply and uniform qualities. However, wool has special and exclusive qualities such as draping abilities, high moisture absorptivity, natural fire resistance, good elasticity, colour-fastness, etc (Grobbelaar, 1985). As finer wool fibres cannot be imitated and still possess an even and satisfactory tensile strength, together with the qualities mentioned, and as technology has not yet advanced to the stage of processing high-micron wool into popular, light garments, fine wool has to be regarded as a speciality textile fibre, which indicates a clear directive for a breeding policy.
Erasmus and Delport (1985) established that during the 1984/85 season, wool buyers had paid enormous premiums for finer wool (Fig. 1) and as objective measuring by the Wool Board has a stabilising effect, a breeding policy to produce a quality fibre in terms of fibre thickness will ensure the survival of the Afrino not only in its own right, but also as a sire-breed for crossbreeding with woolled breeds for fatlamb production.
Before a breeding strategy for wool qualities can be worked out, it is important to ascertain the Afrino's present wool production, what the wool looks like, and what the ultimate ideal is. Wool statistics available for the Afrino is minimal but endeavours are made to create a picture of the breed's wool qualities from statistics collected by the Carnarvon experimental farm (Table A).
It is difficult to make a prognosis for the ultimate ideal wool qualities for the Afrino and anyone venturing into this aspect, should not lose sight of the purpose for which the breed was developed and the environment in which it is to be bred. Its unique and outstanding characteristics afford the Afrino its own identity and to exemplify the characteristics of any other breed as a standard to pursue is dangerous and will be prohibitive on the breed's striving after and establishing its own breeding policy standards. In view of the breed having been defined as a mutton/woolled sheep, a breeding policy for wool production may not be framed so as to be detrimental to mutton production. The proportion of the total body mass of a Merino that consists the fleece is generally calculated as approximately 10%, being a mutton:wool ratio of 10:1. In the case of the Afrino, 3,7% and 27:1 respectively was arrived at, which is an acceptable standard as body mass, which is highly correlated with lambing percentage, is afforded the necessary attention which consequently benefits mutton production. Also, body mass and fleece mass are phenotypically positively correlated which will result in a proportionate increase in wool when selecting for body mass. Selection for an increase in fleece mass is therefore not recommended by only maintaining the present minimum production, as a change in the wool:mutton ratio can possibly develop an animal which will be detrimental to many of the existing special qualities of the breed and proper research will have to precede a change in this ratio. As the Afrino does not compete with breeds that are primarily wool producing, the aforementioned ratio can be considered favourable, provided that the wool is a quality fibre.
Quality traits that can be judged subjectively and described in the breed standards of the Afrino are "quality", which is described as soft to the touch, clear and regular crimp and the absence of foreign and abnormal fibres, while colour in the fleece and watery staples are disqualifications and creeping bellies are discriminations.
Quality traits, which can only be judged objectively, are fibre diameter and staple diameter deviation (Duerden standard). A deviation from Duerden standard is wrongly over-emphasized by breeders as only significant deviations cause problems during processing. Under-stapled wool felts during the washing process, while overstapled wool forms tassels during the carding process. Afrino wool is slightly over-stapled (approximately 110) and although not ideal, it is preferred above understapled wool because the latter weathers more during the wool growth period because the staples become mushy and fall open. Fibre diameter is the factor with the most significant effect on making wool a quality fibre. This is a new trend since the 1984/85 season, which is reflected in the prices of wool of 22 micron and finer (Fig. 1).
This once again underscores the fact that, if wool is a speciality fibre, (22 micron and finer), it will not easily give up its share on the fibre market. Afrino wool's fibre diameter(21,8 micron) is within these limits, but selection for a lower fibre diameter can only increase the revenue realised from wool (Table 2). Length and density are over-estimated and were used in earlier days as a criteria to estimate the quantity of wool. With the advent of modern techniques and equipment, however, wool production can be weighed accurately and thus the criterion whereby quantity was evaluated has developed from an estimation to an exact measuring technique. The use of wool-oil as a preservative should not be overlooked, but the many misconceptions about this characteristic, can easily be observed by simply making a retrospective observation of the South African wool industry. As the production of wool-oil requires much energy and is, in any case, not very effective in its preserving function (Erasmus and Delport, op cit), these two options should be counterbalanced, namely to apply all energy for the production of wool keratin, and to accept that there would be more weathering, or to produce less wool that is also less weathered. Studies will have to determine in which case the consumption efficiency of energy will be best, measured in terms of the quantity of clean wool finally available for processing. Considering the higher calorie content of wool-oil as against wool fibres, it appears that much will have to be sacrificed for the improvement of wool-oil, and probably also mutton and reproductive traits. Erasmus and Delport also raise the question whether an environmental rather than a genetic solution should not be sought, which can vary from a blanket to a chemical, which could probably perform the function better than the natural wool-oil.
A breeding policy to maintain the quantity of wool constant but to improve the quality, in other words, to keep fleece mass constant and decrease fibre diameter will retain the same adapted animal for mutton production, but will ensure an increase in wool revenue which will also increase the total efficiency of the breed, considering the environment in which the breed has to produce.
To realise the breeding policy as spelled out, an objective measuring by the South African Fleece Testing Centre of fibre diameter of young rams will be the only method after selection for mutton qualities and perceptible deviation of wool qualities have taken place. Measuring of fibre diameter in the ewe-flock is not recommended. Although ewes with too strong and deviating wool qualities should also be culled, selection for reproduction and mother qualities should here also be subject to the maximum selection pressure.
ERASMUS, G.J. DELPORT, G.J., 1985. 'n Kritiese beskouing van seleksiedoelwitte by wolskape Simposium oor skaap- en vleisbeesteling. Dept. Veekunde Universiteit van Pretoria. 109 - 122. .
GROBBELAAR, P.D., 1985. Wolprodusente - u moet 'n goeie gehalte produk produseer. Karoo Streeksnuusbrief, Winter 1985. 7.
LAND, R.B., 1981. An alternative philosophy for livestock breeding. Livest. Prod. Sci., 8,95-99.
LERNER, I.M. and DONALD, H.P., 1966. Modem developments in Animal Breeding Academic Press, London.
MOOLMAN, J.L., 1982. Verbruikerseise aan tekstielvesels. S.A. Tydskrif vir Veekunde. 12,235 - 238.
S.A. WOLRAAD, 1985. Wolmark oorsig.
SKJERVOLD, H., 1984. Livestock breeding to meet the needs of the 21st century, pswc.
Afrino Manual 1986 (vol 3)