For two years in New Zealand, ewes either grazed pasture alone or were supplemented daily for the first four weeks of lactation with 0.5 kg (1.1 lbs) of a high protein pellet.
Supplementation did not affect ewe live weight or body condition score or weight of lamb weaned per ewe. Ewe fecal egg counts (FEC) showed a time x supplementation interaction, being reduced by 50% from week six of lactation in both years. After weaning, there was no consistent parasitological benefit to lambs grazing areas where ewes had been supplemented that were reflected in either pasture larvae concentrations, lamb FEC, requirement for anthelmintic treatment, or lamb growth rate.
Despite supplementation of ewes during the first four weeks of lactation successfully reducing ewe FEC by 50 percent, this was not sufficient to provide a measurable and consistent epidemiological benefit to the lambs.
Source: NZ Society of Animal Production