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.
Important Note on history of project
The investigations reported in this paper were conducted under strict, independent veterinary supervision. This was because the responsible animal ethics committee first stated that the proposed study of the efficacy of a novel means of meeting magnesium supplemental requirements was of no academic interest, and refused to assess an application for ethics approval on those grounds. When the first experiment reported suggested the possibility of a prebiotic effect, the committee said that because there was no prior publication of such an effect in ruminants, the experimental hypothesis could not be sustained. This was despite the fact that prebiotic effects were well-known in humans and monogastric animals. As a consequence, the Committee refused to assess the research.
Subsequent investigations (e.g https://peerj.com/articles/18103 ) clearly indicate that the material under investigation could exert the prebiotic effect seen in monogastrics. In light of the present interest in inhibition of methanogenesis, the results reported below are of particular interest, requiring that they be placed in the public domain. Note that across both experiments, no adverse events related to administration of the prebiotic were observed by the veterinarian.
Conduct of the investigations reported has been compared with the ARRIVE guidelines, and found to be compliant.