In the first article of this series we noted the importance of water in dairy cattle rations. By weight, water is the most important nutrient in a milking cow’s ration easily making up greater than 80% of the ration’s total weight. The previous article focused on the chemical and mineral composition of dairy cattle drinking water. Hopefully that article motivated you to have your farm’s drinking water tested for the constituents most often leading to water quality issues: total dissolved solids (TDS), sulfate (SO4), chloride (Cl), iron (Fe) and nitrate-nitrogen (NO3-N).
In our previous article we suggested that further water testing and/or treatment should be considered if the above named constituents are greater than acceptable levels (see Table 1), because at these higher levels these constituents may negatively affect animal health and/or milk production, interfere with the germicidal activity of cleansers and sanitizers (e.g., chlorine) and cause problems with water system components (e.g., pipes and pumps). In fact, some water quality problems such as excess iron can lead to such poor animal performance (e.g., health problems, reduced milk production) that it can be a “business-breaker” (2). High levels of some constituents (e.g., iron, nitrate-nitrogen) can also endanger human health if people are drinking from that water source (1). If levels of these constituents reach “retest levels”; further testing is warranted and one should even consider sending multiple samples to multiple certified laboratories to confirm/deny whether these constituents are problematic. If on further testing a constituent reaches or exceeds “actionable levels” dairy producers should consider consulting professional water treatment options for their cattle’s drinking water.
Water treatment options vary somewhat depending on the water quality issue involved. A major difficulty in treating drinking water on dairy farms is posed by the huge volumes of water involved. Recall that high producing dairy cows may consume up to, or even greater than, 50 gallons of water per day. Multiplying this use over hundreds, or thousands of cows, quickly results in a staggering daily volume of water requiring treatment. Thus, one of the best water “treatment” options may be finding an alternate water source that isn’t plagued with the offending constituent (2).
Water treatment options include distillation (too costly), reverse osmosis (RO), ion exchange resin system (traditional water softener employing salt), oxidation + filtration via aeration (often called an “iron curtain”) and hydrogen peroxide (H2O2) injection systems (2).