173
Views
8
CrossRef citations to date
0
Altmetric
Scientific Article

A critical evaluation of serum methylmalonic acid and vitamin B12 for the assessment of cobalt deficiency of growing lambs in New Zealand

, , &
Pages 137-144 | Accepted 22 Aug 2003, Published online: 22 Feb 2011
 

Abstract

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 deficiency in ill-thriftiness of sheep.

Acknowledgements

AR Sykes is grateful to MeatNZ and WoolPro for financial support of this project.

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

Issue Purchase

  • 30 days online access to complete issue
  • Article PDFs can be downloaded
  • Article PDFs can be printed
USD 213.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.