A review of literature on water medication revealed some detrimental effects on animal production can occur when supplements are fed in drinking water. Detrimental effects could include a reduction in water consumption leading to ill thrift and supplement losses from the water due to water quality problems. Supplement loss can occur without the knowledge of the users. Loss of urea from both the concentrate tanks and water troughs can occur as ammonia and loss of phosphorus can occur by the formation of insoluble compounds which precipitate to the bottom of the concentrate tanks and or water troughs. These supplement losses are normally associated with alkaline water and/or water containing dissolved calcium and magnesium salts. The quantity of supplement lost is not known, but it is likely that it ranges from minor amounts to a large proportion of the urea or P added to the concentrate tanks.
There are several possible practical solutions to avoid supplement loss, but further work is required to test the various possible solutions before water medication can be more widely advocated. Both the Dosatron and the Norprim water medictors offer considerable improvements on the previous equipment. Both medicators do have some problems and the need still remains for improved dispensing equipment. As a small but increasing number of producers are successfully using water medication, it is at least proven under certain field conditions. It is concluded from this that water medication technology is generally sound and considerable benefits can be gained by many more producers in the industry. As some aspects of water medication are not fully understood, caution should still be applied to its use. Further research and development on many aspects of water medication is required before this method can be more widely advocated as a practical and effective means of supplementing livestock. Information available to producers using water medication about supplement formulations and concentrations which can be safely fed is usually inadequate and ad hoc and sometimes misleading.