@conference {41699,
	title = {To wether - short scrotum or leave lambs as entire rams ? Revisiting an old question using new genetics},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {44-47},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {A comparison of wethers (WTH), short scrotum (SSC) and rams (RAM) was made on 552 7/16 Romney, 
3/16 Poll Dorset, 3/16 Texel and 3/16 East Friesianlambs. Lambs were drafted for slaughter using 
commercial criteria on weight and condition score at weaning (D81), D120, D154 and D192. Due to faster 
growth rates, by the end of the 2nd kill (D120) approximately 31\% of RAM and SSC lambs were slaughtered 
compared with 16\% of WTH lambs (P<0.01), although the difference was no longer significant by the end of 
the 4
th
kill. The carcass weight of WTH (17.6kg) was significantly heavier (P<0.01)than the RAM (17.2kg) 
but not significantly different to the SSC (17.5kg), despite similar kill liveweights, due to the increased 
dressing out percentages of the WTH lambs (43.6\%, 43.1\% and 42.5\% respectively; P<0.05). Based on GR, 
8.7\% of WTH carcasses graded overfat, compared with only 0.6\% of RAM and SSC carcasses (P<0.001). 
Over the kill period the price schedule ($/kg carcass weight) dropped, so for the WTH given their longer 
time to slaughter and poorer grading due to over fat carcasses the price for WTH carcasses ($49.16) was 
lower (P<0.01) than RAM or SSC carcasses ($50.37 and $50.70). When the added cost of feeding and 
drenching was taken into consideration, the net value of the WTH was evenless. Composite wether lambs of 
still potentially present an opportunity cost, except incertain situations where the management benefits 
outweigh the direct financial cost. },
	issn = {1176-5283},
	author = {PL Johnson and Kenyon PR and Burnham DL and West DM}
}
