Unhappy cow? A closer look at cow personalities as they mature

A recent study has documented noticeable personality changes in Holstein cows when they undergo puberty, but the media buzz may be overblown.
calendar icon 24 February 2020
clock icon 4 minute read

The Guardian, Smithsonian Magazine and The Cut have all reported on a Royal Society study that focused on the long-term personality traits of cattle. The study suggests that cattle personalities are relatively stable in early life and in adulthood but can undergo noticeable changes when the cows enter puberty. Naturally, the puns were amazing (The Guardian’s “Moo Swings” is a particular gem), but some of the science may have been lost in translation.

Though other research indicates that cows do have a “personality” – behaviours in individual animals that are consistent across different contexts and times – no studies have explored how personality traits develop as individual cows mature. There’s also a gap in the research when it comes to whether personality traits are stable through different development phases or if they change as cows reach sexual maturity and adulthood. This gap interests behavioural researchers since cows, like humans, undergo significant neurological and physiological reorganisation during puberty.

However, some elements of the study design make it difficult to generalise the findings – the “moo swings” recorded in this study could be a one-off observation instead of a reliable behaviour milestone.

How do you give cows a personality test?

Sadly, the researchers couldn’t give the cows a Myers-Briggs test. Instead, personality had to be inferred by observing the cows’ responses to novelty or isolation in standardised tests. The common traits the researchers tracked were boldness (the propensity to take risks when exposed to novelty), exploration (behaviour that gains information about the environment) and sociability (whether or not the cows sought contact with or remained close to other cows).

The researchers carried out three tests that measured the cows’ behavioural responses to novelty during four different development periods: pre-weaning, post-weaning, puberty and during first lactation. The tests were carried out individually and the cows were kept visually isolated from the testing area.

The first test measured the cow’s response to a new environment. Researchers introduced individual cows to an unfamiliar empty arena for 30 minutes and recorded their reactions. The second test recorded the cows’ responses to an unfamiliar person standing in the centre of the arena for 10 minutes. The third test looked at how the cows responded to an unfamiliar object in the centre of the arena for 15 minutes.

After collecting data, the researchers conducted a principal components analysis. This type of test is used on survey data and sees if traits or responses can be reliably grouped together and if there are relationships between them.

The methods are madness

Despite the sound rationale for the study, it falls down in its methodology and implementation. The first issue is that the cows, which were separated into two different cohorts, were selected based on a convenience sample. Though this isn’t cause to discount the results, it does mean that the sample isn’t random or representative, two crucial elements that would make the study more generalisable.

The researchers also collected different data points between the two cohorts – there’s no data for the pre-weaning phase for cohort one, and no data on puberty for cohort two. Because of this, data that establishes baseline personality factors is missing from the analysis.

A final issue is the sample size: both cohorts had fewer than 60 individuals and by the time the cows reached adulthood, the cohorts had 22 and 26 members respectively.

The results

The results from the principal components analysis indicate that the cows had consistent behaviour responses to novelty during early life periods (pre- to post-weaning) and during later periods (post-puberty to lactation). Behavioural responses during puberty showed the biggest departure from early and later development – suggesting that the cows’ personalities changed noticeably when they were adolescents. The results also indicate that behaviour returns to baseline after puberty.

Why it matters

Other research has shown that there’s a link between the personality of domestic animals and their overall productivity, health and welfare. In this case, understanding the individual personalities of calves and cows could help improve management techniques and boost productivity measures.

For example, since previous research demonstrates that cows produce less milk when stressed, identifying easily stressed individuals and taking corrective measures could improve welfare and outputs simultaneously. It can also transition herd-based management strategies to individualised ones, a potential innovation for the cattle industry.

However, the current study doesn’t give conclusive evidence on the relationship between personality and physical development. Despite the researcher’s findings being in line with other publications in the field, additional field trials need to be conducted before the industry can make evidence-based recommendations.

Read the original research paper here.

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