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EFSA: Zeolite and the reduction of risk of Milkfever in Dairy of Cows 2.
Posted by Administrator (admin) on 22-06-2008
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Summary

Milk fever is a hypocalcaemic paresis (disorder of nerve and muscle function) at parturition, caused by the sudden and large demand of calcium from blood due to the onset of lactation. Milk fever, more frequent in older cows with high milk yields, is an economically important disease of dairy cows. If left untreated, about 60 to 70% of such cows die. Surviving cows show reduced milk yield and productive life time.

Most dietary prevention principles of milk fever are directed to the homeostatic regulation of blood calcium and its efficacy, respectively. Low dietary calcium in the prepartum period is seen as one of these preventative dietary regimes. The decrease of availability of feed calcium by adding calcium binding substances may be seen as a further development of the low dietary calcium principle. The crystalline clay mineral zeolite (sodium aluminium silicate) may act as such a calcium binder exchanging its sodium ion with calcium ions and/or other cations.

Zeolite is approved as an anti-caking and anti-coagulant feed additive (Directive 70/524/EC) for all species or categories of animals, for all feedingstuffs. Synthetic sodium aluminium silicate is also used as food additive (E 554).

The present submission requests the use of Zeolite A, a synthetic sodium aluminium silicate with a high cation-exchange-capacity. Its use is proposed at 500-1000 g per day to pregnant dairy cows during the last 2-4 weeks before parturition, subsequently reduced to 500 g for 2 weeks, as calcium binder for the particular nutritional propose of reducing the risk of milk fever in dairy cows. The European Commission asked the European Food Safety Authority to evaluate the effects of these zeolite concentrations on human or animals health or on the environment.

Seven experiments comprising a total of 148 calvings were carried out under a variety of farm conditions. Emphasis was given on the zeolite dose (500-1000 g day), the duration of application (14 or 28 days before expected calving), on the mineral content of the daily ration offered and the effects on Ca, Mg and P blood concentration. No attention was given to animal nutrition details (feed intake etc.) and milk composition.

In nearly all experiments zeolite A supplementation increased the mean serum calcium concentration on the day of calving. Inorganic phosphate and magnesium concentration in blood was lower than in control cows around calving. No information was provided on trace element concentrations.

Zeolite A has the potential to reduce the risk of milk fever in dairy cows, but optimal dosage and duration of treatment are not well established. The FEEDAP Panel is aware of the short term intended use of zeolite, but needs to know also the potential longer term consequences (3 months) in the view of animal health and welfare. The risk for the health of the dairy cow can not be fully assessed because there is insufficient data on magnesium supply and bioavailability of trace elements in treated cows.

No data are given on the potential influence of a zeolite treatment on composition and quality of milk, including the possibility that aluminium content in milk may be increased by release from zeolite at pH < 4.0.
No detrimental effects of zeolite on the environment is expected.

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Last changed: 22-06-2008 at 07:41