Milk fever prevention
Hypocalcaemia (or in its extreme form: clinical milk fever) around calving is caused by the massive draw of calcium (Ca) from the blood to the udder. Three principles to prevent hypocalcaemia are:
- Forcing the Ca metabolism of the dry cow to remain active by keeping its Ca intake low.
- Increasing (the effect of) hormone (PTH) that mobilizes Ca from the skeleton during the last two to four weeks of pregnancy.
- Increasing passive diffusion of Ca across the rumen or gut during the critical period just around calving.
The first principle is highly efficient, provided that the daily intake of Ca can be kept around 20g Ca per cow. The Danish study investigated the use of a calcium binder, synthetic zeolite A (X-Zelit®) in the feed. Zeolite A is known as a water softener in cloth and dish washing products, but also used in many feeding stuff, registered in the EU as a filler and anti caging component in animal feeds.
Methods
The study involved 259 calvings on 22 private dairy farms with a milk fever problem in Denmark. On each farm, treatment and control groups were formed of ten cows each. Heifers were excluded. Thirteen herds were tested on a daily dose of 500 g synthetic zeolite A, nine herds on 250 g/d.
From cows developing milk fever, blood samples were drawn before therapeutic treatment was given and Ca, Mg and inorganic P levels were determined.
Conclusion
Under commercial farming conditions, zeolite treatment at the level of 500g net/d reduced the incidence rate of milk fever among high risk cows from 26.4% to 3.8%.
Palatability
Feed additives to reduce milk fever have a major drawback: low palatability. This is known for anionic salts and is also true for synthetic zeolite A. X-zelit® was accepted by most dairy cows. It is recommended to divide the daily dose into two feedings and mix it instead of putting it on top of the feed.
Presentation
The detailed results of this study by Thilsing, Jørgensen, Eiland and Hansen will be presented on the EBF 2009 - European Buiatrics Forum in Marseille, France, 1-3 December 2009.
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