Identifying sources of yield advantage in beef carcases entered in a commercial bone out competition

Abstract

Proc. Aust. Soc. Anim. Prod. 1996 Vol. 21 IDENTIFYING SOURCES OF YIELD ADVANTAGE IN BEEF CARCASES ENTERED IN A COMMERCIAL BONE-OUT COMPETITION E.R. JOHNSONA, J.C. COWARDB and K. PORTER C * Dept Farm Animal Medicine and Production, The University of Queensland, P.O. Box 125, Kenmore, Qld. 4069 B Queensland Livestock and Meat Authority, P.O. Box 440, Spring Hill, Qld. 4004 'Woolworths Brismeat, Berry Street, Churchill, Qld. 4305 SUMMARY In 30 carcases involving 7 breed types entered in a domestic bone-out competition, 6 carcase components - saleable beef yield, total cuts, hindquarter cuts, forequarter cuts, manufacturing meats and fat trim - were studied in an effort to identify sources of commercial superiority in yield. Piedmontese cross-bred car-cases, with significant advantages in proportions of saleable beef yield, total cuts and forequarter cuts, and a significantly lower fat trim were the greater yielding carcases. There was evidence that this superiority was primarily because of heavy muscling. Limousin cross-bred and Charolais car-cases were generally similar to the Piedmontese cross-bred carcases but each yielded a significantly lower proportion of saleable beef yield. Charolais cross-bred and Poll Hereford carcases were the lowest yielding group, particularly in terms of saleable beef yield, total cuts and hindquarter cuts. The carcases of European breeds of cattle held a distinct yield advantage over those entered in this domestic bone-out competition. Keywords: saleable beef yield, commercial differences, breeds INTRODUCTION Each year the Royal National Association (RNA) of Queensland and the Queensland Livestock and Meat Authority hold a bone-out competition for beef car-cases suitable for the domestic market. The entrants' pens of 3 cattle are slaughtered, dressed, chilled and boned out, using standard procedures (Anon. 1987). The saleable beef yield components (hindquarter cuts, forequarter cuts and manufacturing meats) are priced differentially, and the total car-case value is then related to chilled car-case weight to give a price per kilogram of chilled side weight which enables all entries to be placed in an order of merit for commercial yield. While this is a logical commercial approach to evaluation, it does not identify exactly where or why commercial superiority exists among carcases. The following study was conducted on car-cases entered in the 1995 RNA domestic bone-out competition to define, more clearly, where important commercial differences occurred. MATERIALS AND METHODS Ten pens of cattle, constituting 7 breed types (see Table l), were entered in the competition. The value of each carcase was decided by a differential pricing system for components, which remained the same for all carcases (Table 2). , Table 1. Details of cattle domestic market c&e in the 1995 National Association of Queensland bone-out competition 189 Proc. Aust. Sot. Anim. Prod. 1996 Vol. 21 Because saleable beef yield is usually influenced by degree of fatness of the carcase (Murphey et al. 1960; Preston and Willis 1970; Kempster 1978), the percentages of various carcase components (saleable beef yield, total cuts, hindquarter (HQ) cuts, forequarter (FQ) cuts, manufacturing meats and fat trim) were regressed on rump P8 fat thickness (Moon 1980), treating all 30 carcases as a group. The 10 'pen' groups of car-cases were placed in their 7 represented 'breed type' groups and a test between means of car-case components was applied using Tukey' Studentized Range (HSD) Test (Table 3). Because of close s similarities in data and results between groups of similar genotype, the 7 'breed type' groups were contracted into 4 'breed' groups featuring the predominant genotype. This resulted in 'Charolais', 'Limousin', 'Piedmontese' and 'Poll Hereford' groups in which the means of the carcase components were re-tested (Table 4). Table 2. Prices paid for components of beef carcases suitable for the domestic market RESULTS Regressions of the percentages of saleable beef yield, total cuts, HQ cuts, FQ cuts, manufacturing meats and fat trim on rump P8 fat thickness were non-significant. Table 3 shows the results of the comparison of means for the above 6 carcase components in the 7 'breed type' groups. Table 3. Tukey' HSD test for differences in means of carcase components in 7 'breed type' groups s Table 4 shows the results of the comparison of means of the carcase components in 4 'breed' groups. In the bone-out competition where placement was determined by differential pricing and tissue distribution differences, the Piedmontese cross-bred carcases were placed first followed by Limousin x Droughtmaster, Charolais, Charolais, Limousin cross-bred, Limousin x Santa Gertrudis, Charolais cross-bred, Poll Hereford, Poll Hereford and Charolais cross-bred carcases. The results of the yield study agreed closely with the competition placements, though not precisely. 190 Proc. Aust. Sot. Anim. Prod. 1996 Vol. 21 Table 4. Tukey' HSD test for differences in means of carcase components in four 'breed' groups s DISCUSSION The breed-ignored regressions of percentage saleable beef yield, total cuts, HQ cuts, FQ cuts, manufacturing meats and fat trim on rump P8 fat thickness were not significant, suggesting that fat thickness would not play a major role in yield differences among the lightweight, low-fat carcases entered in this competition. Apart from the Limousin cross-bred carcases, in which the P8 fat thickness range extended from 7 to 18 mm, all groups had similar, narrow, ranges of fat thickness which could be expected to reduce the influence of this measurement in deciding yield differences. The percentage saleable beef yield of the Piedmontese cross-bred carcases was significantly greater than that of the other 'breed types', except for Limousin x Droughtmaster and Limousin cross-bred groups. This yield advantage was attributable mainly to an increased percentage of total cuts which, in turn, was due largely to an elevated percentage of FQ cuts. For the expensive cuts of the HQ, the proportion in the Limousin x Droughtmaster carcases was significantly higher than in the Charolais cross-bred and Poll Hereford groups. The percentage of manufacturing meats did not vary significantly among breeds but Piedmontese cross-bred carcases had significantly less fat trim than the Charolais cross-bred group. Studies of these groups, termed 'breed types', suggested that Piedmontese cross-bred cattle had yield advantages over the Limousin types, which were generally superior in yield to the Charolais and Poll Hereford groups. The method of placing carcases in the bone-out competition, based on differential pricing, was generally confirmed by the yield studies. When analyses were conducted again on the basis of prevailing genotype, loosely termed 'breeds' (Table 4), the Piedmontese carcases had a higher saleable beef yield than the other 3 'breeds' (PcO.OOl), attributable mainly to a greater percentage of total cuts. Limousin carcases had a significantly greater percentage of HQ cuts than the other 'breeds'. There were no significant differences in the proportion of manufacturing meats but Charolais carcases had more fat trim than the other groups. In the characters of commercial importance which were examined in this study, the carcase groups separated basically into 3 groups. The Piedmontese cross-bred carcases showed a yield advantage over the Limousin types which, in turn, were generally superior to the Charolais and Poll Hereford groups. The Piedmontese cross-bred carcases entered in this competition were the progeny of Piedmontese bulls so there was no information available on the yield performance on the maternal side of the cross. Muscle-bone ratio, which is a carcase measurement of particular importance in yield studies (Hankins et aZ. 1943; Berg and Butterfield 1966, 1976) could not be determined in these carcases. However, saleable beef yield-bone ratio, which could be measured, should be a useful substitute in these low fat, lightweight carcases. The Piedmontese cross-bred carcases, with the lowest levels of fat and a saleable beef yield-bone ratio significantly greater than that of the other groups except Limousin types, appeared to owe their yield advantage to greater muscling. Carcases with a high content of European beef breeding show ideal characteristics to satisfy current domestic consumer requirements. Because buyers want highly muscled carcases with a relatively low fat content, European breeds, with fast muscle growth tendencies and a low fat finish at domestic carcase weights, are ideal types. They are likely to be efficient beef producers and frequent winners in domestic carcase competitions which emphasise yield. 191 Proc. Amt. Sot. Anim. Prod. 1996 Vol. 21 ACKNOWLEDGEMENTS We are indebted to personnel of the Queensland Livestock and Meat Authority and Woolworths Brismeat for technical assistance and the provision of facilities to conduct the bone-out competition. REFERENCES ANON. (1987). AUS-MEAT Language, Authority for Uniform Specifications Meat and Livestock, (Australian Meat and Live-stock Corporation: Sydney). BERG, R.T. and BUTTERFIELD, R.M. (1966). Anim. Prod. 8: l-l 1. BERG, R.T. and BUTTERFIELD, R.M. (1976). 'New Concepts of Cattle Growth', (Sydney University Press: Sydney). HANKINS, O.G., KNAPP, B.Jr. and PHILLIPS, R.W. (1943). J. Anim. Sci. 2: 42-9. KEMPSTER, A.J. (1978). In 'Patterns of Growth and Development in Cattle', (Eds H. De Boer and J. Martin) (Nijhoffi The Hague). MOON, J.B. (1980). An Investigation of Alternative Sites for Measuring Fat Depth in Beef Carcases. (Queensland Department of Primary Industries: Brisbane). MURPHEY, C.E., HALLETT, D.K., TYLER, W.E. and PIERCE, J.C. Jr (1960). J. Anim. Sci. 91: 1240. PRESTON, T.R. and WILLIS, M.B. (1970). Intensive Beef Production, (Pergamon: Oxford). 192