No 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.

Certificamos que a proposta intitulada "Impacto de intervenções nutricionais no valor da pegada hídrica do produto leite bovino", protocolada sob o CEUA nº 2267191017, sob a responsabilidade de Julio Cesar Pascale Palhares e equipe; Julio Cesar Pascale Palhares; Taisla Inara Novelli-que envolve a produção, manutenção e/ou utilização de animais pertencentes ao filo Chordata, subfilo Vertebrata (exceto o homem), para fins de pesquisa científica ou ensino-está de acordo com os preceitos da Lei 11.794 de 8 de outubro de 2008, com o Decreto 6.899 de 15 de julho de 2009, bem como com as normas editadas pelo Conselho Nacional de Controle da Experimentação Animal (CONCEA), e foi aprovada pela Comissão de Ética no Uso de Animais da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (CEUA/FMVZ) na reunião de 25/10/2017. We certify that the proposal "Impact of nutritional management on the dairy milk water footprint", utilizing 14 Bovines (14 females), protocol number CEUA 2267191017, under the responsibility of Julio Cesar Pascale Palhares and team; Julio Cesar Pascale Palhares; Taisla Inara Novelli-which involves the production, maintenance and/or use of animals belonging to the phylum Chordata, subphylum Vertebrata (except human beings), for scientific research purposes or teaching-is in accordance with Law 11.

The objective of this study was to compare cattle drinking water consumption collected electronically with that of direct human observation using water metres and to analyse whether an automated system compensates due to its greater precision. The study was conducted in the feedlot of Embrapa Pecuaria Sudeste. The reference unit had four pens: two with electronic drinkers and two with water metres. Experiment 1 utilised 52 Nelore steers and Experiment 2 utilised 44 Canchim steers. Nelore fed a conventional diet, the automated system median daily water intake (DWI) was higher than for animals drinking from the water metre, 17.9 L day-1 and 15.6 L day-1. The reverse was observed for animals fed the co-product diet, the automated system median DWI was 18.9 L day-1 and in the water metre pen was 23.0 L day-1. When the Canchim drank from water metres, the median DWI was lower than with the automated system group, 25.9 L day-1 and 27.8 L day-1, respectively. In Experiment 1, there was a statistical difference between the two sets of equipment for both diets. In Experiment 2, the animals were the same breed, had similar weights and were fed the same diet. There was no statistical difference between the equipment in these conditions. The results indicate that the water meter can have the same performance as high technology at a much lower cost. If a more simplified system for measuring water consumption has the same performance as an automated system, this will justify its use with environmental and economic advantages.

The aim of this study was to evaluate the nutrient fluxes for lactating cows in a pasture-based dairy system and the impact of a nutritional management strategy on the environmental performance indicators. Fourteen lactating cows were divided into two experimental groups with seven animals each. The nutritional managements were a diet containing 20% crude protein (Group 1) and a diet with adjusted protein (Group 2). The nutrient budget was calculated on a monthly basis for nitrogen, phosphorus, and potassium. The nutritional strategy of adjusted protein reduces the total surplus in the lactation period for nitrogen by 7.6% and for phosphorus by 6.3%. The total potassium surplus of the adjusted protein group was 8.5% higher. The average nitrogen use efficiency was 21% for group 1 and 22.7% for group 2. Phosphorus use efficiency ranged from 13.4 to 35% for group 1 and from 15.5 to 34% for group 2 and potassium average use efficiency was 14.2% for group 1 and 12.6% for group 2. Nutritional management reduced nitrogen and phosphorus surpluses as well as the values of the environmental performance indicator. Based on this, it is possible to improve the environmental efficiency of dairy systems through improved nutritional management.