Phosphorus and the grazing ruminant. 4. Blood and faecal grab samples as indicators of the P status of cattle

Author: M.V.P. Read, E.A.N. Engels & W.A. Smith
Year: 1986
Issue: 1
Volume: 16
Page: 18 - 22

Blood plasma and faecal grab samples were evaluated as indicators of P status of cattle grazing at two experimental sites (Glen and Armoedsvlakte). Plasma Pi levels clearly identified the – P cattle at Armoedsvlakte as being P deficient whilst at Glen the – P group tended towards lower levels than the supplemented cattle although differences between them were seldom significant. Plasma levels well below the critical range (2 mg/100 ml plasma) can be useful for identifying a P deficiency but higher levels seem insensitive for distinguishing between groups, as was often observed at Glen. Faecal P levels tended to rank the groups according to their respective intake of P. Poor feed intake of – P cattle at Armoedsvlakte depressed faecal output severely; analysis of grab samples for analysis of percentage P may lead to erroneous conclusions regarding P status. Under these circumstances it would seem advisable rather to determine total P excretion via the faeces to differentiate between the two groups.








Keywords: faecal P grazing cattle, P deficiency, P status, phosphorus, plasma P levels
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