Sheep industry needs long-term plan, says U.K. meat expert

Press, 3 December 1982, Page 19

Sheep industry needs long-term plan, says U.K. meat expert

The importance of a longterm plan for New Zealand's sheep industry has been stressed by Dr A. J. Kempster, chief technical officer of the U.K. Meat and Livestock Commission. Such a plan would allow the sheep industry to be better placed to meet future market requirements, Dr Kempster said in a report to the New Zealand Meat Board. Dr Kempster visited New Zealand earlier this year to review existing research and development work in sheep breeding, carcase evaluation and grading. His report is concerned essentially with the market for lamb, but Dr Kempster said that a number of his recommendations had implications for beef cattle production. Dr Kempster’s recommendations involve largely the collection of basic information. Obtaining that data should be part of a strategic study of the sheep industry, the breed resources available, how they differed in basic characteristics, and how effectively they were matched to different production conditions and market requirements. “Such a study would focus on the longer term rather than the immediate future and highlight areas for promotion and development,” said Dr Kempster. Lamb was competing poorly with other meat and meat products and was seen by the British consumer as the least versatile, fattest and most wasteful meat, said Dr Kempster. Because of the trend away

from traditional meat retailing to self-service supermarkets, together with the development of the convenience food market, lamb would find it increasingly difficult to compete with other meats unless costs were reduced significantly. Dr Kempster recommended that a target area for lamb for the European market be defined. In Britain the target was defined as a carcase weight of 15 to 20kg in fat classes 2 and 3L of the Meat and Livestock Commission's sheep classification scheme (no more than smm of fat over the eye muscle) at the twelfth rib. "A similar target would be sensible for the New Zealand sheep industry, although it would be more difficult to achieve because the average carcase weight is substantially lower,” said Dr Kempster. The target area for carcase characteristics should be kept in perspective with other factors which influenced the over-all profitability of sheep production. Producers should be advised to put as many lambs as possible into the target area provided the returns exceeded the costs. Dr Kempster suggested that producers who are achieving target area lambs should be identified and studied to determine how their production circumstances differed from other producers. “If these producers are also among the most profitable they can be used as a model for improvement.” This was carried out relatively simply in Britain using information from the M.L.C. commercial recording scheme. Commercial recording was not as well developed in New Zealand where it was used primarily for the collection of national statistics — consideration should be given to the extension of the scheme as a management tool. Genetic improvement could be made through two channels, the substitution of existing breeds with improved ones or selection within breeds. Breed substitution was normally the easier channel and could be brought about more rapidly, but this required accurate information on the contemporary performance and carcase characteristics of different breeds. “Such information for carcase characteristics is relatively limited at the moment for the New Zealand sheep population although there is much discussion about the merits of the different breeds. The information available is from relatively small-scale trials and it is not clear how well the sample of animals is representative of national breed populations." Dr Kempster recommended that a national breed trial be carried out to provide the necessary base-line information for decision making. This should involve the contemporaneous comparison of different breeds in a range of production environments. Within-breed selection was a long-term channel for improvement with most of the returns from investment in a breeding programme being recouped between 10 and 15 years in the future. Selection, objectives required careful consideration and response to selection was likely to be weakened considerably if objectives were changed in the course of the selection programme. Dr Kempster said that he gained the impression in New Zealand that selection objectives for carcase characteristics were centred on fat thickness measurements and differentials between

grades in the current export grade schedule. “This is short-sighted and unlikely to lead to an optimum long-term response." The daily rate of lean tissue gain (L.T.G.R.) should be the only carcase objective to be included with other objectives (prolificacy and weight of wool) in selection indexes. L.T.G.R. was a function of three components — daily live-weight gain, kill-ing-out percentage and carcase lean percentage. Breeding research should be aimed at identifying the sires which are ahead of the field in these characteristics. Performance testing offered the simplest and most effective method of selection for L.T.G.R. provided accurate methods were available to measure leanness in live rams. Genetic studies in Britain indicated that selection based on daily live-weight gain would result in lambs with faster lean tissue gain and leaner carcases at a given slaughter weight. “The genetic relationship between daily live-weight gain and L.T.G.R. is a particularly important one and efforts should be made to estimate it as accurately as possible so that within-breed selection programmes can proceed with confidence," said Dr Kempster. “Tissue separation is required to obtain a true indication of carcase lean content: fat thickness measurements are not sufficient.” Dr Kempster recommended that as large a population as possible of the main dual purpose breeds be screened for daily liveweight gain (this could , be done effectively using Sheeplan records), and the best rams and ewes brought together into a central nucleus flock. In this flock ram performance testing for L.T.G.R. would be practiced with high selection intensity. Initially, daily live-weight gain would be the main measured character for carcase improvement, but ultrasonic techniques and other developments in carcase evaluation techniques would be introduced as soon as they are shown to be cost effective for L.T.G.R. improvement. Such a programme should also be considered for the main meat sire breeds although this would have lower priority because of their smaller influence on the national slaughter population. Progeny testing was a possible alternative to performance testing but had added costs and increased generation intervals. Dr Kempster advised against progeny testing unless central testing stations were established with a clearly defined structure of nucleus breeders and multipliers giving rapid dissemination of genetic improvements to the national slaughter population. “In my opinion, the comparison of rams from different breeders to obtain between flock information would be a better use of such a central test facility although this view may not find favour among geneticists who believe that between flock genetic variation is limited.” Among the techniques available for live animal evaluation, ultrasonic machines at present appeared to have the greatest practical value. They are used routinely in pig breeding programmes and increasingly in cattle breeding and research. Dr Kempster said he gained the impression that the level of precision of the D.S.I.R.’s ultrasonic probe had been over-estimated because the probe had been used on samples of sheep with considerable variation

in fatness. The probe was unlikely to be any better than the machines already tested and part of the claimed precision would probably be obtained from visual assessment and handling techniques alone. “This observation requires confirmation before any decisions are taken about the future use of the probe. The research workers should be encouraged to continue their work with the probe to determine what additional precision of prediction is achieved from ultrasonic techniques after live weight, age and handling methods have been taken into account." Future research should focus on new developments in medical scanners which were relatively cheap compared with purpose-built animal machines. Caution should be exercised in the use of conformation as a selection objective. urged Dr Kempster.

“The chances are that response for the selection of

lambs with high L.T.G.R. will be weakened considerably by the identification of fatter rather than more muscular animals. “Consideration should not be given to conformation unless it can be clearly demonstrated that its measurement improves selection response for L.T.G.R.” Dr Kempster defined conformation as the thickness of muscle and fat in relation to the size of the skeleton. Dr Kempster said he was surprised to find that little information on the physical composition of carcases was being collected in the course of research and development programmes. He recommended that tissue separation be carried out as a base-line technique in research and development programmes. A wellequipped carcase evaluation unit had been built at Ruakura and thought should be given to making it the national centre for all carcase evaluation work in New Zealand.