Wednesday, August 9, 2017

What's the environmental impact of pet food?

cat, Hero, hungry, cat food
According to a recent report, we should be concerned about the environmental footprint of pet food.

Should we be concerned about the environmental, and indeed animal welfare footprint, of pet food? A recent paper based on US figures argues that we should. Gregory Okin, from the University of California, Los Angeles, set out to determine how much energy and animal derived products pets consume, and the environmental impact.

The paper is, necessarily, based on a lot of assumptions – from the average sized American dog (22kg +/- 1.2kg) and cat (4.2kg +/- 0.2kg), and their energy requirements (544kJ/kg per day), to the amount of food consumed (the calculations were based on dry foods, as the author states these outsell wet foods by 3:1) to the proportion of animal vs plant derived energy in each food. You can read the methodology in full in the open access paper, published in PLoS ONE.

Assuming these assumptions are correct, the author concludes that in the US, dogs and cats consume 19 +/- 2% of the amount of total dietary energy that humans do, and a whopping 33 +/- 9% of animal derived energy. This is equivalent to the energy consumption of 62 million Americans (about one fifth of the US population). He also concludes that these pets produce a staggering 30 +/- 13% of the faeces that humans do (based on the assumption that humans produce – weight for it – 0.147kg per capita of faeces per day, while cats produce 0.042kg per cat per day, and dogs produce 0.15 +/- 0.07kg  per dog per day.

Because of their diets, Okin conclude that are responsible for 25-30 per cent of land, water, fossil fuel, phosphate, and biocide impacts related to animal production. He estimates that they are responsible for the production of 64 +/-16 million tonnes of greenhouse cases (C02-equivalent methane and nitrous oxide).

What can we do? Okin suggests either reducing the numbers of pet dogs and cats, and/or reducing overfeeding, reducing waste, and developing pet foods based on alternative protein sources would help. Given the number of animals that need homes, the latter solution seems to me more palatable than the former, although avoiding overfeeding of animals is important for their welfare as well as reducing their environmental impact. It also makes sense to consider the animal welfare impact of pet food, although it was not touched on in this paper.

It will be interesting to learn how pet food manufacturers digest this information. Certainly, it seems there is a need for pet foods that have reduced environmental impact.

Please read the full paper (link below).


Okin GS (2017) Environmental impacts of food consumption by dogs and cats. PLoS ONE 12(8):e0181301.