Journal article
A critical evaluation of serum methylmalonic acid and vitamin B12 for the assessment of cobalt deficiency of growing lambs in New Zealand
52, Vol.52(3), pp.137-144
2004
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Abstract
<p>AIM: To derive reference ranges for serum methylmalonic acid (MMA) for the diagnosis of cobalt/vitamin B12-responsiveness in lambs and critique existing serum vitamin B12 reference ranges. METHODS: Individual animal data from earlier supplementation trials, involving 225 ewes, 106 suckling lambs, 301 lambs during the suckling and post-weaning periods and 414 weaned lambs, for which weight gain to supplementation was observed, were used to derive relationships between serum vitamin B12 and MMA, and liveweight gain. RESULTS: Serum MMA concentrations were rarely elevated above the norm of <2 >μmol/L when serum vitamin B12 concentrations were >375 pmol/L, and not elevated into the range where a liveweight response to supplementation occurred (>10 μmol/L) unless serum vitamin B12 concentrations were below 200 pmol/L. Suckling lambs were able to maintain high growth rates despite elevated serum MMA concentrations (>20 μmol/L). CONCLUSIONS: The current reference ranges used in New Zealand for serum vitamin B12 are set conservatively high. Serum MMA concentrations appear to allow better differentiation of a responsive condition than vitamin B12 concentrations. Serum MMA concentrations >13 μmol/L indicate responsiveness to supplementation whilst concentrations <7 >μmol/L indicate unresponsiveness. In the range 7–13 μmol/L, variation in response was observed and predictability of response is less certain, but supplementation is advisable. CLINICAL RELEVANCE: The current reference ranges for vitamin B12 responsiveness are conservatively high and lead to over-diagnosis of vitamin B12 defi ciency in ill-thriftiness of sheep.</p>
Details
- Title
- A critical evaluation of serum methylmalonic acid and vitamin B12 for the assessment of cobalt deficiency of growing lambs in New Zealand
- Creators
- Tini M Gruner - Southern Cross UniversityJ R Sedcole - Lincoln University, CanterburyJ M Furlong - Lincoln University, CanterburyA R Sykes - Southern Cross University
- Publication Details
- 52, Vol.52(3), pp.137-144
- Identifiers
- 1263; 991012821834102368
- Academic Unit
- School of Health and Human Sciences
- Resource Type
- Journal article