Hostname: page-component-848d4c4894-xfwgj Total loading time: 0 Render date: 2024-06-21T06:32:02.287Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of selection for divergent ultrasonic fat depth in rams on progeny fatness

Published online by Cambridge University Press:  02 September 2010

G. L. Bennett ,
H. H. Meyer  and
A. H. Kirton
G. L. Bennett
Affiliation:
Ruakura Animal Research Station, Private Bag, Hamilton, New Zealand
H. H. Meyer
Affiliation:
Ruakura Animal Research Station, Private Bag, Hamilton, New Zealand
A. H. Kirton
Affiliation:
Ruakura Animal Research Station, Private Bag, Hamilton, New Zealand
Get access

Abstract

Fat depths of Southdown and Suffolk rams were ultrasonically measured several times prior to 18 months of age. Ultrasonic measurements were regressed on live weight and deviations from this regression were standardized and summed to select rams with high and low fat depth to produce crossbred progeny for slaughter. An average of 3·24 standard deviations separated high and low sires. Progeny were slaughtered at two ages to determine differences in carcass fatness and its development. A significant difference of 0·5 mm fat depth over the loin eye muscle was found between progeny of low and high sires. Progeny from Suffolk high sires had greater tissue depth over the rib and higher kidney fat weight than those from Suffolk low sires but differences were small or reversed in Southdown progeny. Low progeny had significantly less estimated carcass chemical fat than high progeny. Fat depth C increased less in low progeny between early and late slaughter ages. However, no difference in partition of carcass weight gain to fat weight gain was observed between high and low progeny. Differences in fat weight between high and low progeny, as well as between Southdown and Suffolk progeny, appeared to have occurred prior to the earlier slaughter age.

Type
Research Article
Information
Animal Production , Volume 47 , Issue 3 , December 1988 , pp. 379 - 386
Copyright
Copyright © British Society of Animal Science 1988

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bass, J. J., Woods, E. G. and Paulsen, W. D. 1982. A comparison of three ultrasonic machines (Danscan, AIDD (NZ) and Body Composition Meter) and subjective fat and conformation scores for predicting chemical composition of live sheep. Journal of Agricultural Science, Cambridge 99: 529–532.CrossRefGoogle Scholar
Bennett, G. L., Meyer, H. H. and Kirton, A. H. 1983. Ultrasonic selection for divergence in loin fat depth in Southdowns and Suffolks. Proceedings of the New Zealand Society of Animal Production 43: 115–117.Google Scholar
Botkin, M. P., Riley, M. L., Field, R. A., Johnson, C. L. and Roehrkasse, G. P. 1971. Relationship between productive traits and carcass traits in lambs. Journal of Animal Science 32: 1057–1061.CrossRefGoogle Scholar
Cameron, N. D. and Smith, C. 1985. Estimation of carcass leanness in young rams. Animal Production 40: 303–308.Google Scholar
Clarke, J. N.Bennett, G. L. and Kirton, A. H. 1984. Relative performance of meat breeds of sheep in New Zealand and overseas. Proceedings of the New Zealand Society of Animal Production 44: 239–242.Google Scholar
Fennessy, P. F., Greer, G. J. and Bass, J. J. 1982. Progeny test of selected lean and fat rams. Proceedings of the New Zealand Society of Animal Production 42: 137–140.Google Scholar
Harville, D. A. 1977. Maximum likelihood approaches to variance component estimation and related problems. Journal of the American Statistical Association 72: 320–340.CrossRefGoogle Scholar
Kempster, A. J., Arnall, D., Alliston, J. C. and Barker, J. D. 1982. An evaluation of two ultrasonic machines (Scanogram and Danscanner) for predicting the body composition of live sheep. Animal Production 34: 249–255.Google Scholar
Kirton, A. H., Barton, R. A. and Rae, A. L. 1962. The efficiency of determining the chemical composition of lamb carcasses. Journal of Agricultural Science, Cambridge 58: 381–386.CrossRefGoogle Scholar
Kirton, A. H., Woods, E. G. and Duganzich, D. M. 1984. Predicting the fatness of lamb carcasses from carcass wall thickness measured by ruler or by a Total Depth Indicator (TDI) probe. Livestock Production Science 11: 185–194.CrossRefGoogle Scholar
Nicol, A. M. and Parratt, A. C. 1984. Methods of ranking two-tooth rams for fat-free carcass growth rate. Proceedings of the New Zealand Society of Animal Production 44: 253–256.Google Scholar
Palsson, H. 1939. Meat qualities in the sheep with special reference to Scottish breeds and crosses. Journal of Agricultural Science, Cambridge 29: 544–574.CrossRefGoogle Scholar
Wolf, B. T. and Smith, C. 1983. Selection for carcass quality. In Sheep Production (ed. Haresign, W.), pp. 493–514. Butterworths, London.Google Scholar