Effects of Trichostrongylus colubriformis (Nematoda) on the nutrition and metabolism of sheep. II.* Metabolism of urea

Abstract

The effect of infection with Trichostrongylus colubriformis on the rates of production, excrehon and recycling of urea was studied in 24 Merino lambs. The production rate of urea was estimated as the irreversible loss rate of [¹⁴C]urea given as a single injection.

The feed intake of all sheep was maintained at 540 g/day throughout the experiment.

Parasitized sheep had a higher plasma urea concentration than their paired controls 15–35 days after they were infected. This was associated with an increase in the rate of irreversible loss and the rate of urinary excretion of urea. The additional urea lost in urine is apparently produced from ammonia released from amino acids in the tissues or in the digestive tract. ______________________
*Part I, Aust. J. Agric. Res., 24: 947 (1973).