Coles, G.; Rowarth, J. S.; Pearce, R. J.

Providing a semi-refined chelate of magnesium with mixed organic acids gave controlled magnesium supplementation of equivalent effectiveness to conventional uncontrolled administration of MgO in regard to prevention of milk fever in dairy cows. The supplement was palatable and supplementation produced no adverse health effects as adjudged by veterinary supervision. Monitoring productivity of cows provided with the supplement compared with controls indicated that the use of the supplement provided a paranutritional improvement in feed utilisation, resulting in a significant increase in milk solids yield of up to 23% through the period of supplementation, together with an improvement in body reserves sufficient to sustain a continuing milk solids yield advantage of up to 5% for two months after cessation of feeding. Since this increase in productivity was achieved without an increase in feed intake, use of the experimental supplement is considered to have resulted in a prebiotic effect in ruminant fermentation and consequently a commensurate reduction in methane intensity of production.