Renal Excretion of Urea in Reindeer Effect of Nutrition

Abstract

Renal reabsorption of urea was studied in 8 9-month old reindeer calves fed low protein (19–34 g crude protein, mostly lichens) and high protein (68–69 g crude protein, lichens + soybean meal) diets.

Low protein diets fed for a 3-month period resulted in an average renal reabsorption of 93% of the filtered urea, while only 50 % was reabsorbed on the high protein ration. It was calculated that if the reabsorbed urea was used completely for protein synthesis in the rumen, 4 g crude protein could be made daily in the lichen fed animals. This amount would be a very significant contribution to the nitrogen economy of animals which are usually in a negative nitrogen balance when lichens are the main food consumed.

Sammendrag

Nyrenes reabsorpsjon av urea ble studert hos 8–9 måneder garnie reinkalver foret en lavprotein diett (19–34 g råprotein, hovedsaklig reinlav) eller en høyprotein diett (68–69 g råprotein, reinlav + soyamel).

Foring med lav proteindiett i 3 måneder resulterte i en gjennomsnittlig reabsorpsjon på 93% av den filtrerte ureamengde, mens bare 50% ble reabsorbert på høyprotein dietten. Beregninger viser at den reabsorberte ureamengde forutsatt fullstendig utnyttelse til proteinsyntese i rumen tilsvarer ca. 4 g råprotein pr. dag hos de lavforede dyr. Denne proteinmengde vil være et signifikant bidrag til reinens nitrogen balanse i perioder hvor reinlav er hovedføden.