Liver copper concentration in cattle and herbage copper, sulphur, iron and molybdenum concentrations on commercial farms in the Wairoa region
| Autor: | D. Smith, C.J. Korte, M.G. Lambert, C. Moffat, A.J. Litherland, J. Lee, A. Dowling |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Proceedings of the New Zealand Grassland Association. :75-78 |
| ISSN: | 1179-4577 0369-3902 |
| DOI: | 10.33584/jnzg.1999.61.2358 |
| Popis: | Seasonal changes in herbage elements (Cu, Mo, S, Fe), pasture growth, and soil moisture were measured and their relationships with liver Cu concentration in weaner heifers (n=10–12) and breeding cows (n=10–12) were determined on 7 commercial farms in the Wairoa region. Liver biopsy samples were collected at 2 to 4 monthly intervals and herbage and soil moisture monthly from spring 1996 to spring 1998. Mean Mo concentration of herbage offered to cattle on the 7 farms ranged from 0.7 to 3.2 mg Mo/kgDM and Cu herbage concentrations from 5.7 to 10.5 mg Cu/kgDM. Mean concentrations of Cu in cattle livers ranged from 85 to 204 µmol Cu/kgFW across farms. Herbage Cu, S and Fe concentrations were highly seasonal with low levels in late spring– summer and high levels in autumn and winter. In contrast, herbage Mo was less seasonal. There was a suggestion that variation in liver Cu across seasons was positively affected by increasing herbage Cu concentration and negatively affected by increasing herbage S concentration and unaffected by herbage Mo concentration. Over the two years 46% of nonCu supplemented cows and 32% of weaners had deficient ( |
| Databáze: | OpenAIRE |
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