Effects of Trichostrongylus colubriformis (Nematoda) on the nutrition and metabolism of sheep. I. Feed intake, digestion, and utilization

Abstract

The effect of infection with Trichostrongylus colubriformis on feed intake and its digestion and utilization by young Merino sheep was determined in two separate experiments. Intake of a pelleted chaff diet by infected sheep from 11 to 60 days after infection was 20-30% lower than that of the control animals. Digestion and utilization of the same feed were studied in similar sheep fed hourly a ration of 540 g per day. Infected sheep gained body weight more slowly and produced less wool than the controls. Apparent digestibility of organic matter, energy, and nitrogen was not affected. Urinary excretion of urea nitrogen was increased 21 to 30 days after infection, but excretion of creatinine and other nitrogenous compounds was not affected. Nitrogen retention was lower in infected sheep from 20 to 40 days after infection. The urea nitrogen concentration in plasma samples taken at 20 and 30 days after infection was higher in the infected sheep.