\"Considerable experimental evidence suggests that supplementation with protein can enhance both immune responsiveness and resilience of sheep to infection with gastrointestinal nematode parasites. Practical application of this knowledge is an objective of the Australian Sheep Industry CRC. Field trials were carried out in NSW, WA and SA targeting the most susceptible classes of sheep, i.e., young weaner lambs and/or pregnant ewes. Improved nutrition during pregnancy to maintain a condition score of 3 may lower faecal egg count in ewes in late gestation and during lactation and, importantly for resilience to infection, may produce heavier lambs at weaning. Significant reductions in faecal egg count and improvement in liveweight of ewes and lamb survival were also obtained following short-term protein supplementation pre-partum and the beneficial effects persisted until weaning. Short-term, high-protein supplementation of young weaners was generally beneficial in terms of improving resilience to parasite infection and enhancing liveweight gain and wool growth, but did not always result in lower parasite burdens. The cost-effectiveness of these strategies appears dependent on the level of parasite infection encountered together with the price of supplement used. Environmental factors in the particular region also clearly play a role through influences on forage availability and pasture infectivity.
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