@conference {40370,
	title = {The value of ultrasound in assessing the leg muscling of lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {33-36},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Faecal worm egg counts (FEC) were recorded on 779 lamb progeny  in a performance recorded flock in Northland during summer-autumn 1990  to determine breed and sire variations. Progeny were ram lambs born in  1989 representing 4 Perendale, 4 Romney and 7 cross-bred sires.   The study protocol was that the lambs remained undrenched until the mean  FEC of representative {\textquoteright}monitors{\textquoteright} reached 1000-1500 eggs/g. Then all  stock were faecal sampled, drenched and the protocol repeated. Full  samplings occurred on 12 February (FEC1) and 12 March (FEC2). All  animals grazed as one mob throughout the programme.   There were significant variations within and between breeds in FEC.  Perendale and Crossbred lambs had significantly lower faecal egg outputs  than Romneys on both occasions (FEC1=3560, 4073, 4757; FEC2=2535, 3242,  3737, respectively).   One possible explanation of the results is that Perendales selectively  avoid parasite contamination on pasture through differences in grazing  behaviour. Alternatively, they may have consumed less pasture and  larvae because they were lighter. If these are not the cases these data  suggest that Perendales in this flock may be more resistant to internal  parasites.  },
	issn = {1176-5283},
	author = {Ward BG and Purchas RW and Abdullah AY}
}
