Water use and conservation on a free-stall dairy farm

Abstract

Livestock watering can represent as much as 20% of total agricultural water use in areas with intensive dairy farming. Due to an increased emphasis on water conservation for the agricultural sector, it is important to understand the current patterns of on-farm water use. This study utilized in situ water meters to measure the year-round on-farm pumped water (i.e., blue water) on a ~419 lactating cow confined dairy operation in Eastern Ontario, Canada. The average total water use for the farm was 90,253 ± 15,203 L day-1 and 33,032 m3 annually. Water use was divided into nutritional water (68%), parlour cleaning and operation (14%), milk pre-cooling (15%), barn cleaning, misters and other uses (3%). There was a positive correlation between total monthly water consumption (i.e., nutritional water) and average monthly temperature for lactating cows, heifers, and calves (R2 = 0.69, 0.84, and 0.85, respectively). The blue water footprint scaled by milk production was 6.19 L kg-1 milk or 6.41 L kg-1 fat-and-protein corrected milk (FPCM) including contributions from all animal groups and 5.34 L kg-1 milk (5.54 L kg-1 FPCM) when excluding the water consumption of non-lactating animals. By applying theoretical water conservation scenarios we show that a combination of strategies (air temperature reduction, complete recycling of milk-cooling water, and modified cow preparation protocol) could achieve a savings of 6229 m3 annually, a ~19% reduction in the total annual water use.