Best practice production to reduce the water footprint of dairy milk

Abstract

This study evaluated the impact of diet as a mitigation action to improve the water efficiency of lactating cows. An intensive pasture dairy system was considered to calculate direct and indirect water use. Group 1 was fed with a diet containing 20% crude protein content. The crude protein content of Group 2 was adjusted according to milk production, ranging from 23% to 14.5%. The total water footprints had a value of 502.4 L kg-1 fat protein corrected milk for Group 1 and 451.2 L kg-1 fat protein corrected milk for Group 2. The diet with the adjusted protein provided a reduction of 10% in the footprint value. The green water footprint was the most representative of consumption in the total value of the water footprint, 86.4% and 85.5% for Groups 1 and 2, respectively. The animals in Group 1 had a mean total drinking water consumption of 83.3 L animal-1 day-1 and those of Group 2, 80.4 L animal-1 day-1. This study demonstrated that high crude protein content in the diet provided a greater water footprint, therefore lower water efficiency. The proposed nutritional practice proved viable as a water-mitigating action, making the ratio of liters of water per liter of milk more advantageous. The results of this study could be considered a validation of a nutritional mitigation practice to improve water efficiency and could be used as best management for the dairy supply chain.

Environmental life cycle assessment of cow milk in a conventional semi-intensive Brazilian production system

“…The estimation of the drinking water requirements of the animals is in line with typical practices for the region. Nevertheless, the values were lower than those by Palhares et al ( 2020 ), who determined the drinking water intake for lactating cows by daily recording and measuring. For instance, water footprints observed by Palhares et al ( 2020 ) were 502.4 L per 1 kg FPCM for an animal group fed with a 20% crude protein content diet (group 1) and 451.2 L per 1 kg FPCM for another animal group fed with a diet adjusted according to its milk production (group 2).…”

“…Water is an essential input in dairy farms and demanded for cleaning, for irrigation purposes and for watering the herd (Palhares et al 2020 ).…”

“…There is no way to reduce the water intake, as physiological animal requirements and milk production influence it. However, proper water management, such as automated watering systems, can help minimize water losses, as Palhares et al ( 2020 ) used.…”

Blue Water Footprints of Ontario Dairy Farms

“…It is a direct method to assess the system and evaluate sustainability and it is applicable to many agricultural activities. The blue WF of milk production was calculated per unit kg of FPCM [4,14]. This was achieved by dividing the FPCM [2] from the direct farm water use (washing, spraying/cooling and drinking water of dairy cattle, including lactating cows, dry cows, heifers and calves).…”