Retention of intravenously administered 15N-labelled urea in sheep
Havassy, I.; Boda, K.; Kosta, K.; Rybosová, E.; Kuchár, S.
Physiologia Bohemoslovaca 23(4): 297-303
1974
ISSN/ISBN: 0369-9463 PMID: 4278253 Document Number: 81182
A daily intake of 7.6 g N was raised to 24 g by addition of 22 g urea and each diet was given to 4 adult sheep, twice daily, for a month. Then 301 mg 15N as urea was injected into the jugular vein of 2 sheep. Urine was collected for 24 h and the sheep were then killed. Within 24 h 24 and 56% of 15N from the administered dose was excreted in the urine from sheep on the low- and high-N diets. 15N enrichment of N in the contents of omasum, abomasum, small intestine and in the faeces after 24 h was very small. When 8.4 mg 15N/kg bodyweight was given to the other 2 sheep on the 1st and 3rd day, excretion of label was high only on the day after administration and small amounts were excreted up to the 9th day. Less than 1% of the label was excreted through the gastro-intestinal tract.