A preliminary genetic analysis of breech and tail traits with the aim of improving the welfare of sheep
D. R. Scobie A C , D. O’Connell A , C. A. Morris B and S. M. Hickey BA AgResearch, Lincoln Research Centre, PB4749, New Zealand.
B AgResearch, Ruakura Research Centre, PB3123, Hamilton, New Zealand.
C Corresponding author. Email: scobie@agresearch.co.nz
Australian Journal of Agricultural Research 58(2) 161-167 https://doi.org/10.1071/AR05444
Submitted: 19 December 2005 Accepted: 25 October 2006 Published: 22 February 2007
Abstract
The area of naturally bare skin around the perineum was scored at weaning in lambs (n = 2152) from a composite flock of New Zealand crossbred sheep. Breech bareness was scored on a range from 1, where wool was growing right to the edges of the anus, to 5, where a large bare area surrounded the perineum. Bareness on the under surface of the tail was measured on a linear scale at tail docking. Dag score (degree of breech soiling) was recorded at weaning, on a scale of 0–5, where an increasing score indicated more dags. Dag score was taken as a measure of the risk of flystrike in the breech. Female lambs tended to have slightly greater (P < 0.001) breech bareness score (mean score 2.7) than males (mean score 2.6), whereas mean dag score of females was lower than that of males (0.45 v. 0.53; P < 0.05). Breech bareness score had a heritability of 0.33 ± 0.06, and the length of bare skin under the tail had a heritability of 0.59 ± 0.06. The genetic correlation between breech bareness score at weaning and length of bare skin under the tail at docking was positive (0.35 ± 0.10). These 2 traits had phenotypic correlations with dag score of –0.17 ± 0.02 and –0.03 ± 0.03, respectively, and genetic correlations with dag score of –0.30 ± 0.13 and 0.03 ± 0.12, respectively; negative values indicated a favourable relationship. Tails were removed at docking, so the phenotypic correlation of about zero between tail data and dag score at weaning was of little utility. Our results suggest that selecting for these 2 bareness traits could reduce dag formation and the associated risk of breech strike.
Additional keywords: genetic mulesing, crutching, jetting, sheep welfare.
Acknowledgments
The authors thank the staff who were previously with AgResearch and assisted with the practical aspects of this work, Stuart Young, Phil Barnes, Malcolm Smith, Colin Clemens, Peter Cunningham, Keith Hewitt, Warwick Howie, and Tom Leitch. Norma Merrick was very helpful with respect to both the scientific and practical aspects. Andy Bray was invaluable in encouraging the establishment of the breeding program and latterly in encouraging this manuscript and most importantly the transfer of this technology to New Zealand and Australian sheep breeders. A host of sheep breeders have supported this project, most notably Robin Campbell. This project was funded by Meat and Wool New Zealand and the New Zealand Foundation for Research, Science and Technology.
Archer K,
Farrell R,
Swinton DA, Jackson N
(1982) Scores for variation in wool cover of sheep. Wool Technology and Sheep Breeding 30, 125–132.
Bisset SA, Morris CA
(1996) Feasibility and implications of breeding sheep for resilience to nematode challenge. International Journal for Parasitology 26, 857–868.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
French NP,
Berriatua E,
Kaya G, Morgan KL
(1998) Case control study of diarrhoea and faecal soiling in two to six-month-old lambs. Veterinary Record 143, 408–412.
| PubMed |
Gilmour AR
(1997) ASREML for testing fixed effects and estimating multiple trait variance components. Proceedings of the Association for the Advancement of Animal Breeding and Genetics 12, 386–390.
Heath ACG, Bishop DM
(1995) Flystrike in New Zealand. Surveillance 22, 11–13.
James PJ
(2006) Genetic alternatives to mulesing and tail docking in sheep: a review. Australian Journal of Experimental Agriculture 46, 1–18.
| Crossref | GoogleScholarGoogle Scholar |
Larsen JWA,
Anderson N,
Vizard AL,
Anderson GA, Hoste H
(1994) Diarrhoea in Merino ewes during winter: association with trichostrogylid larvae. Australian Veterinary Journal 71, 365–372.
| PubMed |
Leathwick DM, Atkinson DS
(1995) Dagginess and flystrike in lambs grazed on Lotus corniculatus or ryegrass. Proceedings of the New Zealand Society of Animal Production 55, 196–198.
Leathwick DM, Atkinson DS
(1996) Influence of different proportions of Lotus corniculatus in the diet of lambs on dags, flystrike and animal performance. Proceedings of the New Zealand Society of Animal Production 56, 99–102.
Litherland AJ,
Sorenson E,
Niezen J, Bishop D
(1992) A pilot evaluation of shedding breeds compared with non-shedding breeds for susceptibility to nematodes and flystrike. Proceedings of the New Zealand Society of Animal Production 52, 233–235.
Merrick NC
(2003) Assessment of fleece cover in crosses between Coopworth, Dorper, Damara, New Zealand Wiltshire, Poll Dorset and Suffolk sheep. Proceedings of the New Zealand Society of Animal Production 63, 160–163.
Meyer HH,
Harvey TG, Smeaton JE
(1983) Genetic variation in incidence of daggy sheep—an indicator of genetic resistance to parasites? Proceedings of the New Zealand Society of Animal Production 43, 87–89.
Orwin DFG, Whitaker AH
(1984) Feral sheep (Ovis aries L.) of Arapawa Island, Marlborough Sounds, and a comparison of their wool characteristics with those of four feral flocks in New Zealand. New Zealand Journal of Zoology 11, 201–224.
Pascoe H,
Mullaney PD, Hodge RW
(1976) A comparison of the progeny of a Wiltshire Horn ram mated to Merino, Southdown, Border Leicester-Merino and Corriedale ewes. Proceedings of the Australian Society of Animal Production 11, 33–36.
Rathie KA,
Tierney ML, Mulder JC
(1994) Assessing Wiltshire Horn-Merino crosses: 1. Wool shedding, blowfly strike and wool production traits. Australian Journal of Experimental Agriculture 34, 717–728.
| Crossref | GoogleScholarGoogle Scholar |
Reid TC, Cottle DJ
(1999) Dag formation. Proceedings of the New Zealand Society of Animal Production 59, 52–54.
Scobie DR,
Bray AR, O’Connell D
(1997) The ethically improved sheep concept. Proceedings of the New Zealand Society of Animal Production 57, 84–87.
Scobie DR,
Bray AR, O’Connell D
(1999) A breeding goal to improve the welfare of sheep. Animal Welfare 8, 391–406.
Scobie DR, O’Connell D
(2002) Genetic reduction in tail length in New Zealand sheep. Proceedings of the New Zealand Society of Animal Production 62, 195–198.
Scobie DR,
O’Connell D,
Bray AR, Cunningham P
(2002) Breech strike can be reduced by increased area of naturally bare skin around the perineum of lambs. Proceedings of the Australian Society of Animal Production 24, 201–204.
Thatcher LP, Pascoe HJ
(1973) Who ever heard of a sheep without wool? Journal of Agriculture, Victoria 71, 2–5.
Tierney ML
(1978) Easy care Merinos through cross-breeding with Wiltshire Horn sheep. Wool Technology and Sheep Breeding 26, 21–25.
Waghorn GC,
Gregory NG,
Todd SE, Wesselink R
(1999) Dags in sheep: a look at faeces and reasons for dag formation. Proceedings of the New Zealand Grassland Association 61, 43–49.
