A pilot evaluation of shedding sheep breeds compared with non- shedding breeds for susceptibility to nematodes and flystrike

A.J. Litherland, E. Sorenson, J. Niezen, D. Bishop

AgResearch, Flock House Agricultural Centre, Private Bag 1900, Bulls, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1992, 52: 233-236

Thirty ewe lambs each of Merino, Romney, feral (of Merino origin) and Wiltshire breeds were evaluated for dag score, flystrike and nematode resistance. The lambs were born in August 1990 with the feral lambs around one month younger. The lambs were transported to Flock House and shorn and grazed together from the 21 January 1991 until 1 June 1991.

There was no difference in the geometric mean of faecal egg counts between the different breeds (p=0.11). Lambs were fly struck from February to May with 33%, 10%, 10% of Merinos, Romneys and Wiltshires being attached. No feral lambs were fly struck. Most flystrike was caused by the Australian green blowfly (Lucila cuprina).

The Wiltshire breed had the lowest dag score while the feral sheep had a dag score consistently lower than the Romney and Merino breeds (p<0.001). The wet weight of dag clipped at the end of the experiment was 4 ± 15, 4 ± 16, 30 ± 18, 122 ± 16 g for feral, Wiltshire, Merino and Romney respectively. The dry weight percentage of dags was higher in the feral and Merino (79 ± 3%, 76 ± 3% respectively) than in the Wiltshire (69 ± 3%) or the Romney (61 ± 2%) (p<0.001).

Keywords: NZSAPAB; Feral; Wiltshire; Merino; Romney; flystrike; nematode; dags

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Last Updated 25-01-1997