- Lamb and mutton production - general survey of breeding policies
|Last update: April 10, 2012 11:59:23 AM|
Lamb and Mutton Production
General Survey of Breeding Policies.
L. L. Roux, D. J. Engela and S. W. Bosman
THE desire of farmers to cater to the newly created market grades of mutton and lamb is apparent from the numerous enquiries upon breeding matters received at this College.
Most farmers realize that the quality of slaughter sheep can be improved by using good rams of mutton breeds. It is important, however, to bear in mind that the growth and quality of the lamb and the condition or finish of the mutton sheep depend, very largely upon the quantity and quality of feed provided. A good mutton type of lamb kept under ideal conditions as for example on winter cereal grazing may attain a marketable live weight of 65 lb. within 90 to 120 days. A good hardy mutton type of lamb with a Merino or Persian basis may attain the same weight on excellent veld within 100-130 days. But when veld conditions are adverse, the growth of the lamb will be retarded and it may attain 65 lb. live weight only at the age of 130-200 days. Furthermore, the carcases of lambs, which have been run under hard conditions, do not have sufficient finish and quality to be placed in the higher market grades when the animals are slaughtered at a carcase weight of 30 lb., although they may attain a good finish when the carcase is 5 to 10 lb. heavier.
The Merino as Basis
Considering the breeding aspect it is common knowledge that most mutton and lamb in the Union comes from Merino flocks and non-woolled, fat-rumped and fat-tailed flocks. Relatively little mutton is produced in high-grade and purebred mutton flocks.
Merino-sheep breeders keep their hamels as long as they can because they obtain a lucrative return of approximately 15s. per sheep from their wool. Mature Merino hamels sell well when they are well grown and in good condition. These sheep are generally fattened cheaply, on veld. Few farmers in this country fatten sheep in dry-lot on such feed as maize and lucerne-feeds from which it is possible to make up a most efficient fattening ration. The reason for this is undoubtedly that economic returns are doubtful In other countries the great majority of sheep which are fattened are lambs, this fact being due to their more rapid response in weight increases and, consequently, their greater economic gains. There is also a special demand for the meat of lambs, which therefore sell at a higher price per pound.
At present South African farmers are more concerned with finding types which will make maximum use of available veld and which will put on additional weight and finish when given specially saved good veld or cereal pasture. Hence Merino sheep farmers often resort to crossbreeding to produce a product, which is quicker maturing, superior in conformation and fleshing and, in fact, which is a better all round mutton sheep than the best type of Merino hamel. For this purpose one of the mutton breed rams such as Romney Marsh, Border Leicester, Dorset Horn, German Merino, Ryeland or Southdown is used on well-grown Merino ewes. The merino ewe is not a good milker, however, and, although she does yield a good return from wool, her lamb is not likely to produce a high-grade carcase unless the grazing is particularly good. The crossbred lambs of some of the above-mentioned breeds are kept for further breeding; the hamel lambs are sold when they attain a marketable weight. Dorset Horn, Border Leicester, German Merino and Romney Marsh rams produce a good type of large -framed ewe when crossed with the Merino. When mature, these crossbred ewes weigh from 120-150 lb. and annually produce from 1 to 11 lb. of wool which, at the present prices of wool, means a return of about 7s. to 10s per sheep. What is most important is that these ewes are excellent milkers and also highly fertile.
Excellent results in fat-lamb production may be expected from the above-mentioned types of crossbred ewes when they are mated to a good compact mutton ram, such as the Southdown. Due to the scarcity of purebred mutton tams, their high price, frequent low fertility and high mortality, three-quarter-bred and high-grade Southdown rams have been tried and have been found to give very good results. Information recently published upon research work at the Losperfontein Experiment Station, indicates that when the mother ewe is a crossbred with a Merino base, the use of a high-grade Southdown-Persian ram is strongly recommended. These grade rams are hardy, vigorous, and fertile; they are also ready for use at 9 months of age or even sooner.
It is not recommended that Blackhead Persian and Ronderib Afrikaner rams be mated to Merino ewes for lamb and mutton production. Neither is this recommended In the case of the large-framed crossbred ewes referred to above. Also, the use of a half-bred Southdown-Blackhead Persian or a half-bred Dorset Horn-Blackhead Persian is not recommended for use on Merino ewes and the abovementioned types of crossbred ewes with a Merino basis. Far better results would be obtained by using a three-quarter-bred Southdown-Blackhead Persian or Dorset Horn- Blackhead Persian ram. All the progeny should be sold as they are unsuitable for breeding purposes.
The Non-Woolled Types as Basis
Another aspect of mutton and lamb production in the Union is that involving the use of the non-woolled fat-tailed and fat-rumped breeds and types as mother stock. These breeds are highly fertile and very hardy and also do exceedingly well under semi-arid conditions. Unfortunately they are slow maturing; the young sheep reach 65 lb. at the age of about 5 to 8 months, most of them at the latter age. In addition, they are easily adversely effected by internal parasites and by cold wet weather. What is very important is that their conformation and mutton qualities are poor, and that they have a very undesirable localization of fat. This type of lamb and mutton is becoming more unpopular as greater attention is being paid to better grade products.
Extensive experiments conducted by this College and at other centres have proved that very considerable improvement is brought about by mating rams of various improved mutton breeds, such as the Southdown, Dorset Horn, Suffolk, etc., to ewes of the non-woolled breeds and types. It was found that the half-bred type was most hardy; further infusions of improved mutton blood reduce hardiness. Hence the ¾- and ⅞-bred improved mutton-breed grades are less hardy than the ½-bred.
Unfortunately, many of the exotic pure breeds of mutton sheep have not proved to be readily adaptable to the environmental conditions in this country. In most cases disease, especially of the lungs, shortens the life of the animals and, consequently, restricts their period of usefulness. Furthermore, most exotic breeds lack the type and degree of hardiness and vigour which are essential in most areas in this country. It is highly probable that many of the improved mutton breeds, such as the British mutton breeds, will become better adapted to South African conditions when they have been bred and reared in this country for a number of generations.
The objects aimed at by the use of improved mutton breeds rams on non-woolled ewes are largely as follows:
The breeding of lambs and sheep which are suitable material, in themselves, for slaughter.
The breeding of material suitable for further breeding with the object of improving the female breeding stock to ensure more rapid growth und better mutton qualities.
In the first object mentioned above, the intention should be to use sires capable of contributing the maximum amount of good mutton qualities to their progeny. The purebred improved mutton breeds are most capable of accomplishing this. Of the many breeds tested, the Southdown has given the best results when mated to the non-woolled types of sheep. In view of the difficulties involving disease, etc., in the pure-breds, grades of these breeds have been tested and found to be very satisfactory. The results obtained by using either ¾-or ⅞-grade rams are very similar. It has been found that, when purebred Dorset Horn rams are used, lambing difficulties are sometimes experienced, especially in the case of maiden ewes and when conditions are favourable and the lambs are well developed.
The second breeding policy indicated above aims at the establishment of more suitable breeding material. As the half-bred type is the most hardy, it is recommended that a new type be established at the half-bred level by breeding the half-bred inter se and selecting for the desirable characteristics. For instance, rapid conversion of the flock of Blackhead Persian can be brought about by using (preferably) Dorset Horn rams on Persian ewes. The half-bred rams selected for breeding should be of the desired types by well-bred rams out of good ewes. An attractive ram which has been sired by a well-bred ram, but out of a nondescript ewe, should not be used for building up a type. A slightly longer process, but less involved and somewhat less costly, is the use of good half-bred rams on the Blackhead Persians from the start. This obviates the danger of loss of the purebred rams, and also considerably simplifies mating management. The same procedure should be followed in the case of conversion of a nondescript flock of non-woolled sheep. Rams for further breeding, however, should not be selected from those bred out of the flock, but, as previous indicated, should be by a purebred improved mutton sire such as a Dorset Horn out of good Persian ewes.
In the selection of the material for establishing a uniform half-bred type, particular attention should be paid to uniformity within the flock and individuals should exhibit good mutton conformation with symmetry and a minimum amount of localized fat.
An advantage in using the Dorset Horn in establishing the half-bred type is that this, breed has two breeding seasons a year, which permits the breeding of autumn as well as spring lambs and under very favourable conditions, may allow farmers to obtain three lambs in .two years. Most British breeds of sheep, which have been under observation in this country, lamb only in the spring and crossbreds obtained from these breeds inherit this characteristic. The Dorset Horn has been found to possess excellent milking qualities which are transmitted to the hardy crossbred type mentioned. All farmers appreciate the advantages of having ewes which are good mothers. Experimental evidence has established the fact that normal and healthy growth of the lambs can be attained by supplying favourable conditions during the first 5 to 6 months of its life. Differences of over 50 per cent in weight increase may be experienced by lambs of the highest as compared to those of the lowest milk-producing ewes.
The point it is intended to emphasize especially is that sufficient information is available to permit guidance along certain very definite lines of lamb and mutton breeding procedure under intensive and extensive conditions. The object is to induce farmers to make the best use of the material, woolled and non-woolled, at present available in the country and to aim at the establishment of types which, because of their special characteristics, will play an important role, in the lamb and mutton production of the Union in the future.
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