Abstract

The interaction between parasitism and crude protein (CP) nutrition on calf liveweight gain (LWG) was investigated. One hundred and twelve calves were either administered 21,000 parasite larvae (73% Cooperia oncophora, 16% Ostertagia ostertagi, 11% Trichostrongylus axei) twice per week or drenched fortnightly with anthelmintic for 12 weeks. Calves grazed ryegrass pastures and received 40% of their diet as either low (15% CP) or high (26% CP) protein pellets. Half of the calves switched diets after six weeks. All treatments averaged a liveweight gain of at least 1 kg/d. After 12 weeks non-parasitised calves were 13 (standard error of difference (SED 2.0)) kg heavier than parasitised calves (P <0.001), and calves fed a high protein supplement were 12 (SED 2.8) kg heavier than those fed low protein supplement (P <0.001). There was no interaction between diet and parasitism (P = 0.74). Subsequentlycalves grazed together for a further 12 weeks with no supplements or parasite dosing. The liveweight advantage of the high protein supplement was lost, while non-parasitised calves maintained a liveweight advantage of 15 (SED 4.9) kg (P <0.01). While protein supplementation did not affect faecal egg count or blood pepsinogen it has the potential to improve LWG with less reliance on anthelmintics under field conditions.

VT, Burggraaf, MR Puha, and AA Adler

Proceedings of the New Zealand Society of Animal Production, Volume 68, Brisbane, Australia, 113-116, 2008