Forward creep grazing of lambs to increase liveweight gain and post‐weaning resistance to endoparasites

Abstract

An experiment was conducted in New Zealand to assess the effect of creep grazing of lambs on their liveweight and resistance to endoparasites. Comparisons included creep versus non‐creep grazing at two herbage allowances and regular an‐thelmintic drenching. Treatments commenced with 6‐week‐old twin reared lambs, and ceased when they were weaned at 13 weeks, with the exception of the drench treatment which continued post‐weaning. Pastures used contained sheep endoparasites. At 8 weeks post‐weaning one lamb from each twin set was slaughtered, remaining lambs were then drenched, and 8 and 9 days later were orally dosed with 180 Trichostrongylus colubriformis L3/kg liveweight each day (averaging 12 650/lamb). Three weeks later these lambs were also slaughtered. Measurements included liveweight, faecal worm egg count (FEC) and adult endoparasite numbers. Neither herbage allowance nor creep grazing affected FEC or adult endoparasite numbers. Fortnightly drenching of creep grazed lambs on the high allowance had no effect on weaning liveweight, but it improved live‐weights post‐weaning. Neither creep grazing, pre‐weaning herbage allowance, nor drenching, affected lamb resistance to endoparasites. Creep grazing and the higher allowance both increased weaning liveweights. The response to creep grazing was highest at the lower allowance, increasing weaning liveweights by 4 kg. Pre‐weaning treatment had no effect on post‐weaning growth rate.