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Sulfur and chlorine play a non-acid base role in periparturient calcium homeostasis
Citation
Roche, JR and Morton, J and Kolver, ES, Sulfur and chlorine play a non-acid base role in periparturient calcium homeostasis, Journal of Dairy Science, 85 pp. 3444-3453. ISSN 0022-0302 (2002) [Refereed Article]
DOI: doi:10.3168/jds.S0022-0302(02)74432-9
Abstract
The increased risk of periparturient hypocalcaemia through offering high-K feeds in the precalving period has been reported previously. Two experiments (experiment 1 and 2) investigated the effect of KCl fertilizer on pasture mineral concentration, the dietary cation-anion difference (DCAD), and the subsequent effect of this on periparturient plasma and urine mineral status. Experiment 2 examined the effect of precalving Mg source (MgO, MgSO 4 , and MgCl 2 ) and postcalving Ca supplementation on the concentration of Ca and Mg in plasma and urine. Unexpectedly, pasture DCAD increased (P = 0.06) from 434 to 535 mEq/kg DM in experiment 1 as pasture K concentration decreased from 4.2 to 3.5%, primarily because of a corresponding and greater decrease in pasture Cl concentration (from 1.9 to 1.3%). Plasma Ca or Mg concentrations were not affected by pasture K concentration. A linear decline (P < 0.10) in urine Mg suggested a decline in Mg absorption as pasture K increased. In experiment 2, pasture DCAD decreased (P < 0.05) linearly from 403 to 350 mEq/kg DM as pasture K concentration decreased from 3.8 to 3.3%. However, precalving urine pH was not affected by the declining DCAD. Postcalving plasma Ca concentration was affected by precalving Mg source with MgSO 4 > MgCl 2 > MgO. Differences in acid-base balance do not explain the difference between Mg salts. These results indicate that precalving dietary S and Cl concentration plays an important role in Ca homeostasis, in addition to its role in acid-base balance. Supplementation with Ca postcalving increased plasma Ca concentration for 2 d postcalving. Milk production was not affected.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Agricultural and Veterinary Sciences |
| Research Group: | Animal Production |
| Research Field: | Animal Nutrition |
| Objective Division: | Animal Production and Animal Primary Products |
| Objective Group: | Livestock Raising |
| Objective Field: | Dairy Cattle |
| Author: | Roche, JR (Dr John Roche) |
| ID Code: | 40813 |
| Year Published: | 2002 |
| Web of Science® Times Cited: | 48 |
| Deposited By: | Agricultural Science |
| Deposited On: | 2007-10-22 |
| Last Modified: | 2007-10-22 |
| Downloads: | 0 |
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