Last update: September 2, 2011 01:18:49 PM E-mail Print


Breeding SA Mutton Merinos for the future.

GJ Erasmus


GENETIC improvement of a breed is extremely slow and therefore a long-term process. Much has been done to speed up the process but even if all modern technology is utilized, it remains relatively slow. When formulating breeding objectives this fact must always be considered. It implies that, although we must breed what the market requires, it is not the market demands of the present but rather the market demands of the future that are important. Breeding today is a science, not an art, but predicting future trends correctly appears to have everything to do with art - with a lot of luck thrown in. The success of a breeder and the size of his bank balance will eventually be determined firstly by how well he was able to foresee changes in market requirements and secondly by how successful he was in changing his sheep to meet those requirements.

Apart from predicting correctly which traits will need changing, knowledge is also needed of how readily a specific trait can be changed genetically and how changes in such a trait will affect other traits. The latter two questions are not as difficult to answer as it may seem and much is already known about how traits will react to selection and what correlated responses can be expected. An effort is already being made to estimate these parameters specifically for South African Mutton Merino flocks.

The question of where emphasis in selective breeding should be placed is far more difficult and potentially dangerous to try and answer as it involves more than just genetics. In fact, by using modern effective genetic procedures and evaluation techniques a breeder will reach his goal far sooner. If this goal happens to be misplaced, it will merely speed up his progress in the wrong direction and make it more difficult to turn back. For instance, a breeder with genuine fine wool sheep today could be laughing all the way to the bank at the advice given by other breeders (and scientists) until fairly recently that production was all that mattered and that this could be more easily achieved by breeding strong wool.

Three of the questions (there are no doubt many more) S A Mutton Merino breeders with an eye to the future are asking themselves are:


1. What must I do with that useful bonus, the wool that I shear off my sheep?

Firstly, all indications are that it would be foolish to neglect it completely and one could even increase production without this having a negative effect on the other more important properties of the breed. It is however essential that measurements are made on all the important traits so that selection can be made objectively and changes can be monitored accurately.


What about the price demands for S A Mutton Merino wool?

It is a known fact that, all other things (e.g. fibre diameter) being equal, Merino wool is the most sought after and therefore the most expensive. This was borne out in a recent study at the Fleece Testing Centre. However, it also emerged that the "breed" effect on price is relatively small compared to that of fibre diameter. It would therefore be economically more feasible and probably far easier to select for finer typical S A Mutton Merino wool than to try and breed a S A Mutton Merino with a typical Merino wool. If such a wool is bred on a S A Mutton Merino it would probably not even sell at a premium as it could be more weathered being less dense than that of a pure Merino.


2. What must I do about size?

The indirect effect of size on fertility and maintenance requirements is perhaps of more importance than its direct effect. The effect of body weight on fertility has, until fairly recently, been a confusing issue because of contradictory evidence. Researchers at the Animal and Dairy Science Research Institute at Irene have related body weight and fertility to the "genetic landscape" principle proposed by Prof. Lush. They have shown that increasing body weight leads to an increase in fertility but wonder whether this is the case with S A Mutton Merinos. At least one breeder claims he has evidence that those sheep that are slightly below average for mature body weight are the most fertile. Breeders participating in performance testing will be able to supply this information.

It stands to reason that the bigger the sheep, the higher its maintenance requirements. The ideal situation for prime Iamb production is a small fertile ewe and a ram that can sire a fast-growing lamb. In practice this can best be achieved by crossbreeding, but, of course, crossbreeding has other problems. The point is, S.A. Mutton Merino breeders will have to decide how important crossbreeding will become in prime lamb production. Will the S A Mutton Merino as a pure breed be able to compete with crossbreeding or does its future lie in providing terminal sires in crossbreeding programmes? The answer to this question will of course influence selection decisions especially as far as size or mature body weight is concerned.


3. What about future input costs?

This is probably the most important question: spiralling input costs are presently the farmer's biggest nightmare. If this spiralling tendency is to continue, the S A Mutton Merino's ability to utilize low quality roughage will not only become its most important attribute, but it will have to be exploited even further. This implies that the stud breeder will have to select his animals in a low cost environment to make doubly certain that he is selecting the animals best capable of producing under these conditions. Commercial producers are no longer impressed by maximum production irrespective of cost, but are interested in optimum production at the lowest possible cost. It is a delicate balance that ensures maximum profit. If stud breeders are becoming alarmed at the cost of preparing sale rams, think of the commercial producer who has to buy expensive rams and not sell them. If the commercial producer can no longer afford high input costs, the stud breeder will have to supply him with cheaper (not necessarily inferior but less well prepared) rams capable of producing progeny that can best utilize his prevailing conditions. If they have been raised and selected under more or less such conditions they would possibly do just that. The glamour of high prices and the prestige - not to mention the income -bestowed on a few select individuals are not to be scoffed at. However, the long-term success of a breed depends on how popular it is with commercial producers and this popularity is increasingly being based on economic considerations.

The increasing popularity of the S A Mutton Merino is a sign that the breeders have made good decisions in the past. The decisions they make today will determine the future of the breed in the extremely competitive small stock industry in South Africa.



Prestige South African Mutton Merino journal 1 (1)