Water use on nonirrigated pasture-based dairy farms: Combining detailed monitoring and modeling to set benchmarks

Abstract

Water use in intensively managed, confinement dairy systems has been widely studied, but few reports exist regarding water use on pasture-based dairy farms. The objective of this study was to quantify the seasonal pattern of water use to develop a prediction model of water use for pasture-based dairy farms. Stock drinking, milking parlor, and total water use was measured on 35 pasture-based, seasonal calving dairy farms in New Zealand over 2 yr. Average stock drinking water was 60 L/cow per day, with peak use in summer. We estimated that, on average, 26% of stock drinking water was lost through leakage from water-distribution systems. Average corrected stock drinking water (equivalent to voluntary water intake) was 36 L/cow per day, and peak water consumption was 72 L/cow per day in summer. Milking parlor water use increased sharply at the start of lactation (July) and plateaued (August) until summer (February), after which it decreased with decreasing milk production. Average milking parlor water use was 58 L/cow per day (between September and February). Water requirements were affected by parlor type, with rotary milking parlor water use greater than herringbone parlor water use. Regression models were developed to predict stock drinking and milking parlor water use. The models included a range of climate, farm, and milk production variables. The main drivers of stock drinking water use were maximum daily temperature, potential evapotranspiration, radiation, and yield of milk and milk components. The main drivers for milking parlor water use were average per cow milk production and milking frequency. These models of water use are similar to those used in confinement dairy systems, where milk yield is commonly used as a variable. The models presented fit the measured data more accurately than other published models and are easier to use on pasture-based dairy farms, as they do not include feed and variables that are difficult to measure on pasture-based farms.

Application of circular economy principles to New Zealand pastoral farming systems

“…In 2006, 78% of New Zealand's extracted water was used for irrigation, 3% for livestock drinking, with the remainder for public and industry use (New Zealand Parliament 2011). An estimated 26% of stock drinking water is lost through leaks, which, in turn, can damage pasture and increase energy use for pumping water (Higham et al 2017). Electricity use in New Zealand produces average emissions in CO 2 equivalents (CO 2 e), of approximately 150 g CO 2 e/kWh (unpublished data S. Falconer and S. Ledgard 2020), compared to 2,990 g CO 2 e/L diesel and 2,760 g CO 2 e/L petrol (Ledgard et al 2020).…”

A Global Review of Monitoring, Modeling, and Analyses of Water Demand in Dairy Farming

“…Across four AMS brands, Brøgger Rasmussen and Pedersen [27] calculated an average parlor water consumption of 0.4 L w kg −1 milk, equal to that consumed by the traditional milking systems. Higham et al [28] also monitored and analyzed 35 pasture-based dairy farms (herd size range = 160-1150 cows) in New Zealand over a period of two years (June 2013 to May 2015) and calculated a parlor water usage value of 3.9 L w kg −1 milk. In Germany, Krauß et al [29] analyzed the cleaning water use within a dairy barn (herd size = 176 cows), autonomously monitoring hourly water usage across two milking systems (a herringbone and an AMS) over 806 days.…”

“…This concurred with findings reported by Robinson et al [33] in which 17 Ontario dairy farms were analyzed and found to consume greater volumes of water during the summer months than in winter (p < 0.05). In New Zealand, Higham et al [28] utilized 35 pasture-based dairy farms to calculate an average drinking-water consumption of 60 L w cow −1 day −1 , although this figure was corrected to 36 L w cow −1 day −1 when adjusted for leakage (mean milk production of 12.8 kg cow −1 day −1 ). Contradictory to Brugger and Dorsey [26] and Robinson et al [33], Higham et al [28] reported reduced total water usage during the summer months.…”

“…Higham et al [28] utilized metered water data from 35 New Zealand dairy farms (herd size range = 160-1150 cows) and data related to climatic conditions, farm characteristics, and milk production to develop regression models to predict dairy-farm total direct water demand (drinking plus parlor). They selected model input variables based upon their ability to explain the variability of the observed data.…”

“…Model accuracy was then assessed on unseen data using 50-fold cross-validation. Higham et al [28] found that the regression model with six input variables of maximum ambient temperature, evapotranspiration, radiation, milk solids (MS), milk volume, and whether a rotary or herringbone milking parlor was employed was able to explain 90% of the overall variability (R 2 = 0.90). Model coefficients are shown in Table 4.…”