Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-19T07:24:29.617Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of rapid inbreeding and of crossing inbred lines on the growth of linear body dimensions of sheep

Published online by Cambridge University Press:  02 September 2010

G. Wiener ,
G. J. Lee  and
J. A. Woolliams
G. Wiener
Affiliation:
AFRC Institute of Animal Physiology and Genetics Research, Edinburgh Research Station, Roslin, Midlothian EH25 9PS
G. J. Lee
Affiliation:
AFRC Institute of Animal Physiology and Genetics Research, Edinburgh Research Station, Roslin, Midlothian EH25 9PS
J. A. Woolliams
Affiliation:
AFRC Institute of Animal Physiology and Genetics Research, Edinburgh Research Station, Roslin, Midlothian EH25 9PS
Get access

Abstract

Sheep of three hill breeds and the crosses among them were closely inbred for four generations to create five levels with inbreeding coefficients 0·0 (F2/O2), 0·25 (I1,), 0·375 (I2), 0·50 (I3), and 0·59 (I4). Inbred females were also mated to unrelated inbred males of the same breed or crossbred type to produce line-crosses (LC). Mating was arranged so that the effects of inbreeding on the individual could be differentiated from maternal inbreeding. A total of 2369 animals were available up to 78 weeks of age and 1062 to the age of 4 years. This study examines the effects on six linear body dimensions and draws comparison with the effects on body weight. There were significant reductions in the size of the body dimensions with increasing inbreeding but the maximum depression was usually at the I2 stage for individual inbreeding and the I3 stage for maternal inbreeding. Most of the linear and many of the non-linear effects of inbreeding of the individual were significant and the effects of maternal inbreeding were also significant in a majority of cases. Inbreeding effects were more marked for relatively late-maturing parts (shoulder and hook widths) than for early-maturing (cannon bone and tibia lengths) with head width and body length intermediate but closer to the early-maturing parts. This was seen separately at each age, and in the effects of advancing age. By 78 weeks of age, the effects of inbreeding of the individual on absolute size had increased with age and by 4 years of age, in spite of a small recovery in size relative to F2/O2, was still greater than in early life. The effects of maternal inbreeding became progressively less with advancing age relative to non-inbreds. The changes with inbreeding could not be explained by dominance effects alone and epistasis is therefore likely also to be involved.

Keywords

body measurementsgrowthinbreedingline differencessheep
Type
Research Article
Information
Animal Production , Volume 55 , Issue 1 , August 1992 , pp. 101 - 114
Copyright
Copyright © British Society of Animal Science 1992

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

Blaxter, K. L., Fowler, V. R. and Gill, J. C. 1982. A study of the growth of sheep to maturity, journal of Agricultural Science, Cambridge 98:405–420.CrossRefGoogle Scholar
Butterfield, R. M., Griffiths, D. A., Thompson, J. M., Zamora, J. and James, A. M. 1983. Changes in body composition relative to weight and maturity in large and small strains of Australian Merino rams. 1. Muscle, bone and fat. Animal Production 36: 29–37.Google Scholar
Harvey, W. R. 1977. Users' guide to LSML76. Mixed model least squares and maximum likelihood program. Ohio State University, Columbus.Google Scholar
Slee, J., Wiener, G. and Woolliams, C. 1988. A comparison of inbred and outbred sheep on two planes of nutrition. 2. Responses to acute cold and heat exposure. Animal Production 46: 221–229.Google Scholar
Wiener, G. and Hayter, S. 1974. Body size and conformation in sheep from birth to maturity as affected by breed, crossbreeding, maternal and other factors. Animal Production 19: 47–65.Google Scholar
Wiener, G., Lee, G. J. and Woolliams, J. A. 1992. Effects of rapid inbreeding and of crossing of inbred lines as the body weight growth of sheep. Animal Production 55:89–99.Google Scholar
Wiener, G., Woolliams, C. and Slee, J. 1988. A comparison of inbred and outbred sheep on two planes of nutrition. 1. Growth, food intake and wool growth. Animal Production 46: 213–220.Google Scholar
Woolliams, J. A. and Wiener, G. 1981. The effect of breed type and inbreeding on characteristics of the fleece and skin of 12-week-old Iambs. Animal Production 32: 9–22.Google Scholar