@conference {41514,
	title = {Embryo transfer for improved feed conversion efficiency in cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {246-251},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Two experiments were conducted to understand the interactions between calf weaning date, level of nutrition and parasite  challenge. In the first experiment, spring-born calves were weaned at 6 or 9 months of age (early  or late weaning) and subject  to  natural parasite challenge, or natural plus an additional dose of 7500 infective larvae/day. Late weaned calves (with cows) also had  either high or low pasture allowance treatments imposed. When calves were 9 months of age, calf liveweights (kg) were 253, 302 and  277 (SED 3.9) for the early wean/high nutrition, late wean/high nutrition and late wean/low nutrition treatments respectively and high  and low nutrition cow liveweights were 494 and 479 kg (SED 4.8) respectively. At 9 months of age, early weaned calves showed  higher faecal egg counts (P<0.05). Dosing with additional parasitic larvae had no effect on early weaned calves, but lowered late  weaned calf weights. In the second experiment, calves were weaned at 6 months of age or left un-weaned until the age of 9 months  when all calves were slaughtered. Un-weaned calves showed lower gastro-intestinal worm counts than early weaned calves. In both  experiments, late weaned calves showed substantial liveweight advantage and lower parasite burdens. Reducing the nutrition of late  weaned calves and cows reduced the size of this liveweight benefit. Later weaning is a management option for farmers seeking to  reduce reliance on anthelmintic drenches without the associated production loss.  },
	issn = {1176-5283},
	author = {Smeaton DC and Scott ML and Webby RW and McGowan L and Cameron C and Brooky A}
}
