Across population genetic parameters for wool, growth, and reproduction traits in Australian Merino sheep. 1. Data structure and non-genetic effects
E. Safari A G , N. M. Fogarty A , A. R. Gilmour A , K. D. Atkins A , S. I. Mortimer B , A. A. Swan C , F. D. Brien D , J. C. Greeff E and J. H. J. van der Werf FA The Australian Sheep Industry Cooperative Research Centre, NSW Department of Primary Industries, Orange Agricultural Institute, Orange, NSW 2800, Australia.
B NSW Department of Primary Industries, Agricultural Research Centre, Trangie, NSW 2823, Australia.
C CSIRO Livestock Industries, Armidale, NSW 2350, Australia.
D South Australian Research and Development Institute, Roseworthy, SA 7371, Australia.
E Department of Agriculture and Food, Western Australia, Great Southern Agricultural Research Institute, Katanning, WA 6317, Australia.
F School of Rural Science and Agriculture, University of New England, Armidale, NSW 2351, Australia.
G Corresponding author. Email: alex.safari@dpi.nsw.gov.au
Australian Journal of Agricultural Research 58(2) 169-175 https://doi.org/10.1071/AR06161
Submitted: 12 May 2006 Accepted: 16 October 2006 Published: 22 February 2007
Abstract
Accurate estimates of adjustment factors for systematic environmental effects are required for genetic evaluation systems. This study combined data from 7 research resource flocks across Australia to estimate genetic parameters and investigate the significance of various environmental factors for production traits in Australian Merino sheep. The flocks were maintained for several generations and represented contemporary Australian Merino fine, medium, and broad wool bloodlines over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, with over 2700 sires and 25 000 dams. Univariate linear mixed animal models were used to analyse 6 wool, 4 growth, and 4 reproduction traits. This first paper outlines the data structure and the non-genetic effects of age of the animal, age of dam, birth-rearing type, sex, flock, bloodline, and year, which were significant with few exceptions for all production traits. Age of dam was not significant for reproduction traits and fleece yield. Generally, wool, growth, and reproduction traits need to be adjusted for age, birth-rearing type, and age of dam before the estimation of breeding values for pragmatic and operational reasons. Adjustment for animal age in wool traits needs to be applied for clean fleece weight (CFW), greasy fleece weight (GFW), and fibre diameter (FD) with inclusion of 2 age groups (2 years old and >2 years old), but for reproduction traits, inclusion of all age groups is more appropriate. For GFW, CFW, and hogget weight (HWT), adjustment for only 2 dam age groups of maiden and mature ewes seems sufficient, whereas for birth (BWT), weaning (WWT), and yearling (YWT) weights, adjustments need to be applied for all dam age groups. Adjustment for birth-rearing type (single-single, multiple-single, multiple-multiple) is appropriate for wool, growth, and reproduction traits. The implications of adjustment for non-genetic effects are discussed.
Additional keywords: adjustment factors, dam age, birth-rearing type, age.
Acknowledgments
Funding for this study was provided by the Commonwealth Government through the Australian Sheep Industry Cooperative Research Centre. We also gratefully thank the many other scientists and technical and support staff who have contributed to the management of the flocks and collected the data over many years, from the Agricultural Research Centre, Trangie, and NSW Department of Primary Industries; CSIRO Livestock Industries, Armidale; Turretfield Research Centre and the South Australian Research and Development Institute; the Great Southern Agricultural Research Institute, Katanning, and the Department of Agriculture and Food Western Australia. Contributions of sheep breeders and industry funding bodies such as Australian Wool Innovation and Meat and Livestock Australia and their predecessors over many years to the various flocks are also gratefully acknowledged.
Brown DJ,
Tier B,
Reverter A,
Banks R, Graser HU
(2000) OVIS: a multiple trait breeding value estimation program for genetic evaluation of sheep. International Journal of Sheep and Wool Science 48, 285–297.
Brown GH,
Turner HN,
Young SS, Dolling CHS
(1966) Vital statistics for an experimental flock of Merino sheep. 3. Factors affecting wool and body characteristics, including the effect of age of ewe and its possible interaction with method of selection. Australian Journal of Agricultural Research 17, 557–581.
| Crossref | GoogleScholarGoogle Scholar |
Clément V,
Bibe B,
Verrier E,
Elsen JM,
Manfredi E,
Bouix J, Hanocq E
(2001) Simulation analysis to test the influence of model adequacy and data structure on the estimation of genetic parameters for traits with direct and maternal effects. Genetic Selection Evolution 33, 369–395.
| Crossref | GoogleScholarGoogle Scholar |
Cloete SWP,
Scholtz AJ,
Gilmour AR, Olivier JJ
(2002) Genetic and environmental effects on lambing and neonatal behaviour of Dormer and SA Mutton Merino lambs. Livestock Production Science 78, 183–193.
| Crossref | GoogleScholarGoogle Scholar |
Dickerson GE, Glimp HA
(1975) Breed and effects of lamb production of ewes. Journal of Animal Science 40, 397–408.
File GC
(1981) Highly fertile Merinos and their nutritional management through pregnancy and lactation. International Journal of Sheep and Wool Science 29, 7–11.
Gregory IP, Ponzoni RW
(1981) Genetic studies of South Australian Merino sheep. II. Environmental effects on wool and body traits at 15–16 month of age. Australian Journal of Agricultural Research 32, 657–667.
| Crossref | GoogleScholarGoogle Scholar |
Gregory IP,
Roberts EM, James JW
(1977) Genetic improvement of meat sheep. 4. Effects of age of dam on productivity of Dorset and Border Leicester sheep. Australian Journal of Experimental Agriculture and Animal Husbandry 17, 735–740.
| Crossref | GoogleScholarGoogle Scholar |
Hohenboken W,
Corum K, Bogart R
(1976) Genetic, environmental and interaction effects in sheep. I. Reproduction and lamb production in ewe. Journal of Animal Science 42, 299–306.
Lax J, Brown GH
(1967) The effects of inbreeding, maternal handicap and range in age on 10 fleece and body characteristics in Merino rams and ewes. Australian Journal of Agricultural Research 18, 689–706.
| Crossref | GoogleScholarGoogle Scholar |
Lewer RP,
Woolaston RR, Howe RR
(1992) Studies on Western Australian Merino sheep. I. Stud, strain and environmental effects on hogget performance. Australian Journal of Agricultural Research 43, 1381–1397.
| Crossref | GoogleScholarGoogle Scholar |
Lewis RM,
Shelton M,
Sanders JO,
Notter DR, Pirie WR
(1989) Adjustment factors for a 120-day weaning weight in Rambouillet range lambs. Journal of Animal Science 67, 1107–1115.
Lush JL, Shrode R
(1950) Changes in milk production with age and milking frequency. Journal of Dairy Science 33, 338–357.
Maniatis N, Pollott GE
(2003) The impact of data structure on genetic (co)variance components of early growth in sheep, estimates using animal model with maternal effects. Journal of Animal Science 81, 101–108.
| PubMed |
Mortimer SI, Atkins KD
(1989) Genetic evaluation of production traits between and within flocks of Merino sheep. I. Hogget fleece weight, body weight and wool quality. Australian Journal of Agricultural Research 40, 433–443.
| Crossref | GoogleScholarGoogle Scholar |
Mortimer SI,
Atkins KD,
Eissen J,
Van Heelsum A,
Burns AM, Isaac BR
(1994) Effect of changing Merino ram source on average hogget production and wool quality levels and between-animal variability. International Journal of Sheep and Wool Science 42, 243–252.
Mullaney PD, Brown GH
(1970) Some components of reproductive performance of sheep in Victoria. Australian Journal of Agricultural Research 21, 945–950.
| Crossref | GoogleScholarGoogle Scholar |
Notter DR
(2000) Effects of ewe age and season of lambing on prolificacy in US Targhee, Suffolk, and Polypay sheep. Small Ruminant Research 38, 1–7.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Notter DR,
Borg RC, Kuehn LA
(2005) Adjustments of lamb birth and weaning weights for continuous effects of ewe age. Animal Science 80, 241–248.
| Crossref | GoogleScholarGoogle Scholar |
Ponzoni RW,
Grimson RJ,
Jaensch KS,
Smith DH,
Gifford DR,
Ancell PMC,
Walkley JRW, Hynd PI
(1995) The Turretfield sheep breeding project: messages on phenotypic and genetic parameters for South Australian Merino sheep. Proceedings of the Australian Association of Animal Breeding and Genetics 11, 303–313.
Ponzoni RW,
Jaensch KS,
Grimson RJ,
Smith DH,
Ewers AL, Ingham V
(1999) South Australian Merino selection demonstration flocks: background and first hogget results. International Journal of Sheep and Wool Science 47, 83–94.
Safari E,
Fogarty NM, Gilmour AR
(2005) A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livestock Production Science 92, 271–289.
| Crossref | GoogleScholarGoogle Scholar |
Safari E,
Fogarty NM, Gilmour AR
(2006) Sensitivity of multi-trait index selection to changes in genetic correlations between production traits in sheep. Australian Journal of Experimental Agriculture 46, 283–290.
| Crossref | GoogleScholarGoogle Scholar |
Taylor PJ, Atkins KD
(1997) Genetically improving fleece weight and fibre diameter of the Australian Merino—the Trangie QPLU$ Project. International Journal of Sheep and Wool Science 45, 92–107.
Turner HN,
Brown GH, Ford GH
(1968) The influence of age structure on total productivity in breeding flocks of Merino sheep. II. Flocks with a fixed number of breeding ewes, producing their own replacements. Australian Journal of Agricultural Research 19, 443–475.
| Crossref | GoogleScholarGoogle Scholar |
Turner HN, Dolling CHS
(1965) Vital statistics for an experimental flock of Merino sheep. II. The influence of age on reproductive performance. Australian Journal of Agricultural Research 16, 699–712.
| Crossref | GoogleScholarGoogle Scholar |
Walkley JRW,
Ponzoni RW, Dolling CHS
(1987) Phenotypic and genetic parameters for lamb and hogget traits in a flock of South Australian Merino sheep. Australian Journal of Experimental Agriculture 27, 205–210.
| Crossref | GoogleScholarGoogle Scholar |
Yazdi MH,
Eftekhari-Shahroudi F,
Hejazi M, Liljedahl LE
(1998) Environmental effects on growth traits and fleece weights in Baluchi sheep. Journal of Animal Breeding and Genetics 115, 455–465.
