Dry pet foods are better for the environment

The population of pet dogs and cats is growing worldwide, with the U.S. estimated to have 76.8 million dogs and 58.4 million cats. Brazil has about 52.2 million dogs, and China has 53.1 million cats. Despite these significant increases, the environmental impact of pet diets is still unclear. 

According to a new study led by the University of São Paulo in Brazil, cat and dog owners could significantly reduce the environmental impact of their pets’ diets by feeding them dry food – such as kibbles or biscuits – rather than wet food with higher water content.

The scientists evaluated the environmental impacts – including greenhouse gas emissions, and land and water usage – of 618 diets for dogs and 320 diets for cats in Brazil. These diets included both commercial wet and dry diets found on the websites of three major Brazilian pet food retailers, and several homemade diets. In addition, the researchers also assessed the nutritional and caloric values of the different diets.

The investigations revealed that wet diets for both cats and dogs had the highest environmental impacts, particularly compared with dry diets. Homemade diets appeared to have intermediary environmental impacts, although water usage in homemade cat diets was about the same as that in dry diets. The scientists estimate that a ten-kilogram dog consuming on average 534 calories per day would be responsible for 828.37 kilograms of carbon dioxide per year when fed a dry diet, compared to 6,541 kilograms for a wet diet – a staggering seven-fold increase.

According to the researchers, dry diets provide the highest amount of energy per gram, while wet and homemade diets provide higher amounts of protein. Since in wet diets, almost twice as much energy is provided by animal ingredients than in dry diets (45.42 percent versus 89.27 percent), they have a much greater environmental impact.

These findings – published in the journal Nature Scientific Reports – highlight the massive environmental impact of pet foods and the urgent need to make them more sustainable.

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By Andrei Ionescu, Earth.com Staff Writer