Dag score is negatively correlated with breech bareness score of sheep
D. R. Scobie A C , D. O’Connell A , C. A. Morris B and S. M. Hickey BA AgResearch, Lincoln Research Centre, Private Bag 4749, Christchurch 8140, New Zealand.
B AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand.
C Corresponding author. Email: scobie@agresearch.co.nz
Australian Journal of Experimental Agriculture 48(7) 999-1003 https://doi.org/10.1071/EA07397
Submitted: 10 December 2007 Accepted: 16 April 2008 Published: 20 June 2008
Abstract
At weaning in two consecutive years, traditional Romney and composite lambs (crosses with East Friesian and Texel; n = 3254) were observed on a conventional farm and Perendale and composite lambs (crosses with Texel, Wiltshire and small numbers of Finnish Landrace; n = 2095) were observed on an organic farm. Both were ram breeding farms recording pedigree and performance, and the composite breeds were developed from, and run with, the original flock on each farm. Breech bareness was scored on the lambs between 80 and 120 days of age on a scale from 1, with wool right to the edge of the anus, to 5, where a large bare area surrounded the perineum. Dag score was recorded on a 0–5 scale where an increasing score indicated more dags. Within farms, mean dag score was more pronounced in traditional Romney (1.2) than in composite lambs (0.4), and Perendales were more daggy (1.3) than composite lambs (0.7) across both years (P < 0.001). Dag score was phenotypically correlated with breech bareness score on the Romney farm (−0.18 ± 0.02) and Perendale farm (−0.27 ± 0.03). Combining data from both flocks, heritabilities of breech bareness score (0.55 ± 0.04) and dag score (0.41 ± 0.05) were high, and a strong genetic correlation was observed between the two traits (−0.59 ± 0.07). Mean dag score of ram lambs was greater than ewe lambs (0.8 v. 0.7, P < 0.001) and lambs reared as twins were more daggy than singles (0.8 v. 0.7, P = 0.008). Composite sheep have been adopted throughout New Zealand for the advantages they deliver in lamb production, but through breech bareness they also provide an opportunity to limit dag production and thereby improve both welfare and profitability. Genetically increased breech bareness and decreased dagginess could be used in Australia as alternatives to mulesing.
Additional keyword: flystrike protection.
Acknowledgements
We are grateful to Meat and Wool New Zealand for the investment that allowed us to conduct this work and for the ongoing involvement of Dr Andy Bray. We are also very grateful to the Richardson family and the Welsh family for having us on their farms and in their homes during weaning.
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