There are many environmental and animal welfare concerns associated with the dairy industry. Farmed cows are selectively bred to produce excessive amounts of milk beyond their natural capacity, with harmful impacts on their health such as increased udder infections, lameness, and reproductive problems. To maximize milk yields, they’re separated from their calves shortly after giving birth, which negatively affects the well-being of both. Male calves, considered surplus to the industry because they don’t produce milk, are usually killed at birth or raised for meat. At the same time, dairy production contributes to greenhouse gas emissions, land use, and water pollution disproportionately.

In contrast, plant-based milk alternatives such as soy, oat, or coconut milk provide essential nutrients while having a lower environmental impact — and all without using animals.

Many consumers are unaware of factory farming practices and informing them about what happens on farms has the potential to influence their food choices. In particular, images of animals suffering on farms may be an effective strategy to raise awareness and change consumer behavior.

In this study, researchers wanted to measure the impact of an anti-dairy social marketing campaign on people’s consumption of dairy and plant-based milks. The researchers chose to use billboards because people can’t easily avoid them, especially in crowded and high-traffic areas, and past studies have shown that they’re considered useful, trustworthy, and reliable sources of information compared to other forms of marketing.

The campaign was organized as follows:

• Design: The billboards included an image of a crying cow, the statement “Dairy cows cry when we take their babies away for milk,” a call to action to try plant-based milks, and a link to the study’s website.
• Location: Six billboards, two big and four small, were placed in locations around a U.K. city (the “Billboard City”) either in the city center or along high-traffic roads heading into the city center. Another U.K. city was chosen as the control (the “Control City”) and had no billboards.
• Length: The billboards were left up for one month.

The researchers then measured dairy and plant-based milk consumption using three novel methods:

1. The first method involved analyzing sales data from plant-based milk companies to compare the Billboard City to the rest of the United Kingdom. This data is commercially sensitive so only two companies ended up agreeing to participate under strict confidentiality agreements.
2. The second method involved collecting cafe sales data in both cities to compare the proportion of hot drinks sold containing dairy or plant-based milks. Ultimately, only six cafes in the Billboard City responded. No cafes in the Control City participated.
3. The third method involved examining residential waste to estimate milk consumption. The researchers photographed the top layer of communal garbage disposals in both cities (18 in the Billboard City and 32 in the Control City) before and after the billboard intervention. They analyzed these images, identifying the plant-based and dairy milks and the volume of the bottles.

Did The Billboards Impact Plant-Based Milk Sales?

Over the month of the campaign, the study’s website got 170 views from 45 unique users. However, the researchers weren’t concerned about this relatively modest traffic as the main ask of the billboards was to try plant-based milk, not visit the website.

Comparing the month before the campaign began to after the campaign ended, the proportion of sales of hot drinks with plant-based milk increased by 1.5 percentage points in the Billboard City cafes. Unfortunately, the researchers couldn’t determine if this was statistically significant or unique to the Billboard City because there was no data from the Control City for comparison.

Analysis of the two plant-based milk companies’ sales showed that the billboards had a positive impact when compared to the control. Sales for one company were 23 percentage points higher in the Billboard City for the month the billboards were up, which increased to 25 percentage points after the campaign. While less dramatic, sales for the other company in the Billboard City remained three percentage points higher during the campaign and four percentage points higher once the billboards were removed.

Finally, residential waste analysis showed a fall in the proportion of milk coming from plant-based milk in both cities, but the drop was much higher in the Control City (-49%) than in the Billboard City (-30%). This suggests that residents from the Control City consumed less plant-based milk than the Billboard City residents, which supports the positive effect of the billboards.

Limitations

Unfortunately, the billboards only ran for one month and data was only compared for the month after they were removed, which prevented measuring longer-term effects. Also, there were many factors outside of the researchers’ control that could have impacted people’s plant-based milk consumption. For example, other plant-based milk promotions, advocacy efforts, or the media could have affected consumer behavior and, of course, the results.

What Does This Mean For Advocates?

Overall, the study was inconclusive with respect to the impact of the billboards because of the various limitations the researchers encountered. However, as the findings indicated a positive — albeit small — impact on people’s consumption habits, the researchers suggest that billboards may be a simple and cost-effective form of advocacy. For the study, they managed to rent six billboards in a major U.K. city for around £6,000 in 2023, which means that animal advocates could feasibly sponsor a single billboard for as little as £500 for a two-week run.