26 Aug 2022
David Rendle, BVSc, MVM, CertEM(IntMed), DipECEIM, FRCVS and Tamzin Furtado BA(Hons), PhD consider psychology and parasitology in this article about educating clients
Image: © Jag_cz / Adobe Stock
A certain irony exists in the fact we can’t seem to get horse owners to vaccinate enough, yet we can’t seem to dissuade them from deworming too frequently. To determine why, we need to try to understand what motivates horse owner behaviour.
Some may think that understanding horse owners is an impossible task, but this is an evolving science with an increasing amount of work being performed into the social science of pet ownership.
Regrettably, horse owners may be influenced more by social norms than professional advice and are, therefore, potentially more likely to do what everyone else on the yard is doing than what their vet suggests they do. This highlights the value of managing populations of horses as a herd and seeking the engagement of the yard-owner/manager in implementing change.
Infectious diseases, including parasites, cannot be controlled effectively through implementation of change at an individual horse level; change is required at herd level. Herd management can be challenging in dynamic equine populations or populations with mixed ownership, but this mindset is necessary if we are to optimise protection against infectious disease and anthelmintic resistance.
Different models exist for analysing human behaviour; however, the COM-B model1 is a framework that has been applied widely within human and animal health2-5. Similar analytical approaches are also exploited in commercial settings to encourage consumer spending6.
Application of the COM-B model to horse owner behaviour, alongside application of key principles of behaviour change, can assist in clarifying how changes in infectious disease control might be achieved. The COM-B model suggests that “behaviour” is influenced by three areas:
For the past two decades, equine health care providers have been encouraging horse owners to move away from routine use of anthelmintics at calendar-based intervals toward a diagnostic-led approach.
However, the increasing prevalence of anthelmintic resistance would suggest that change has not been fast enough, and genuine fears now exist that equine welfare and the viability of equine businesses will be compromised by untreatable endoparasitic disease.
Rates of horse keeper engagement with diagnostic-led parasite control appear relatively low7,8 and sales of anthelmintics have not diminished significantly in the UK9. Furthermore, premises that have the highest stocking densities and present the greatest risk for anthelmintic resistance are least likely to adopt diagnostic-led approaches10, and an overdependence remains on the newest class of equine anthelmintics, the macrocyclic lactones7,8,10,11.
A review of factors that motivate human behaviour change highlights why efforts to date have had limited impact and provides insight into the measures that need to be implemented if meaningful reductions in anthelmintic use are to be achieved12.
Any specific behaviour, such as the act of using a faecal worm egg count (FEC) to target the use of anthelmintics, happens because of a complex interplay of factors including: a person’s knowledge, the physical skills they might need, their social environment, how the physical environment shapes what they can and cannot do, and their automatic behaviours or habits13,14.
Current approaches to encourage diagnostic-led approaches rely on education, aiming to improve horse keepers’ knowledge and motivation, in the hope this will change their behaviour. However, this approach is limited in that it targets only one area of potential behavioural influence, and we need to move beyond our assumption that change in knowledge will alter behaviour.
Approaches relying on educating people often fail to consider the wider context of behaviour15,16. For example, decades of education aimed at reducing the use of free plastic bags in supermarkets failed to achieve its aim, while small simple changes to the physical environment (a small charge and having to request a bag rather than having them readily available at checkout) markedly reduced disposable plastic bag consumption17.
Despite educational initiatives, the level of understanding of anthelmintic use among horse owners has been demonstrated to be poor, even among those who are regularly performing FEC and believe they have a good understanding of parasite control7,10.
Even when they are performed, diagnostics are often integrated inappropriately and opportunities to reduce the use of anthelmintics are missed.
Equine endoparasite control is complex and must consider multiple variables. It is, therefore, inevitable that information from different sources will vary, and while it may be accurate in each individual situation, the apparent inconsistency of message tends to undermine trust and compliance18.
Questionnaire surveys have demonstrated that most horse owners think about deworming on a regular basis and, while most horse owners value the opinion of their vets, a minority use them as their primary source of advice7. The advice that horse owners obtain from other sources is not always reliable; they frequently turn to other horse owners or yard owners who may have no qualifications, and even when they refer to suitably qualified persons, the advice received may not be more in line with datasheet recommendations than current best practice.
Further challenges arise from the application of risk to an owners’ individual situation. People find it hard to apply abstract risks to their personal situation, unless they have personal experience of that risk19,20. This is true of anthelmintic resistance: while horse keepers are aware it is an issue, they do not consider that it relates to their own horses, and do not perceive that parasitic disease will happen to their horses or on their property21; they suffer from an optimism bias.
This effect is likely to be amplified by the low rate of testing for anthelmintic resistance, which prevents horse keepers from gaining first-hand experience of resistance in their own horses.
Many owners make ad-hoc decisions on deworming, and do not have a herd or even individual horse plan that considers parasite control in the round. Therefore, an opportunity exists for greater veterinary engagement in the development of annual plans for parasite control.
Annual health plans would ideally consider the prevention of other infectious disease risks in addition to the threats posed by parasites. The process needs to be made as simple as possible, and messaging needs to be consistent to minimise confusion and maximise trust in the programme.
Unfortunately, diagnostic-led parasite control will always be less convenient for both horse keeper and animal health care provider. More work is required, and on premises with mixed horse ownership logistical and political challenges must be overcome.
It is far easier to buy and administer a tube of anthelmintic than it is to keep horses segregated to obtain faecal samples, collect and label them, submit them, discuss the results and then treat the minority of horses that require anthelmintics.
It is recognised that owners of larger numbers of horses are less likely to engage with diagnostic-led parasite control22 – likely because the amount of effort required increases. With the reduction in cost of anthelmintics over recent decades, it is far cheaper to treat than to perform diagnostics, and as the number of horses increases, so the perceived financial penalty for acting responsibly also increases.
A few studies have identified cost as a factor that discourages horse owners from adopting a diagnostic-led approach23-25.
The ease with which horse keepers can purchase and use anthelmintic products (particularly online) in the absence of any professional advice severely hampers efforts to promote change, because the undesirable behaviour is so much easier than the desirable behaviour. Horse keepers are not obliged to follow advice and can simply select a different source of anthelmintic if they do not receive the advice they want.
For owners who have made the move towards diagnostic-led approaches to anthelmintic use, evidence suggests that reflective motivation is a factor, as these owners showed an understanding of the potential risks of anthelmintic resistance or had a desire to avoid the use of chemicals in their horses21.
Increasing interest in sustainability and the environment may become an increasingly powerful motivator of behaviour change as evidence of the ecotoxicity of some equine anthelmintics emerges.
Convincing horse owners of the importance of vaccination can feel like a constant struggle. Despite the recent prominence of vaccination and its obvious benefit in controlling COVID-19, it remains difficult to persuade owners of the benefit to their individual horse.
We all have a tendency toward an optimism bias and many horse owners see influenza as something that is unlikely to affect them, and so they take the decision that they do not need to vaccinate.
With far less than 50% of the UK’s horses vaccinated against influenza and far lower numbers vaccinated against other contagious diseases, a powerful social norm for not vaccinating exists. Regrettably, many owners are more likely to be influenced by the majority of their peers who are not vaccinating than the vet who advises that they should vaccinate.
If we can increase rates of vaccination then the social norm could become a powerful motivator in favour of vaccination; however, with vaccination rates having remained relatively static for many years, this seems an unlikely prospect unless, as with diagnostics for parasite control, use of vaccines is mandated.
Rates of vaccination in the UK are far lower than in other northern European countries of similar socioeconomic status and it is unclear why the UK lags so far behind. In Finland, rates of vaccination are estimated to be from 85% to 95% – more than double the influenza vaccination rate in the UK26.
Despite the challenges, veterinary surgeons play a very important role in educating horse owners, yard managers and event organisers about the importance of vaccination, in addition to wider infectious disease control and preventive measures.
Equestrian bodies and sporting organisations may have the greatest potential to change horse owner behaviour through encouraging and potentially insisting on vaccination at gatherings of horses. Influenza remains a constant threat, with outbreaks being recorded frequently across the UK – invariably triggered by disease in unvaccinated horses. In the past 12 months, 26 outbreaks have been recorded.
While education of the morbidity and mortality associated with influenza virus is important, experience of low vaccine uptake against the far more emotive Hendra virus (which is transmissible between and rapidly fatal for both horses and humans) suggests that education of the potential consequences of not vaccinating may not be sufficient27.
Concerns around side effects in a new and “untested” vaccine, and a lack of trust in health care professionals (veterinary surgeons and doctors) and the pharmaceutical industry, were the primary reasons for not vaccinating against Hendra virus27. Research into vaccine hesitancy around human vaccines was growing even before the COVID pandemic brought it into sharp focus, and could provide insight into possible outcomes for vaccine roll-out and uptake in animals28,29.
Vaccine hesitancy is defined by a reluctance or refusal to be vaccinated, or to have an individual vaccinated. The World Health Organization considers vaccine hesitancy to be in the top 10 global threats to human health.
In a 2019-20 study of equine veterinary surgeons in the UK, 86.4% of respondents reported vaccine hesitancy from horse owners – most commonly due to perception of over-vaccination, cost and concern regarding adverse events30.
A survey of nearly 5,000 UK horse owners in 2016 identified several factors that were associated with lower vaccination rates; some geographical locations, increasing horse owner age, annual household income of less than £15,000 and owning more than one horse31.
Horse-related factors that were associated with lower influenza vaccination rates included age ranges of less than 4 years old and more than 20 years old, use as a companion or breeding animal, or leaving their home premises either never or at most once a year. The most common reasons cited for failing to vaccinate horses was no competition activity, lack of exposure to influenza and expense of vaccines.
In contrast, the most common underlying reasons given by horse owners who vaccinated their horse were protection of the individual horse against disease, veterinary advice and to protect the national herd31.
What under-vaccinating and over-worming behaviours have in common is that they are each the path of least resistance, given that giving one anthelmintic product is easier than conducting an FEC and acting accordingly, and not vaccinating is obviously easier than arranging a vet visit by a specific date –particularly if the date is missed and the horse then requires additional boosters. Additionally, both actions have the lowest immediate cost, although they may have a higher long-term cost.
Choosing the easiest option behaviour-wise reflects a well-known construct of human behaviour, which is that people often choose the most “frictionless” short-term behaviour possible, even if longer-term drawbacks may exist; an aspect discussed at length by numerous behaviour numerous change theorists32-34.
Given that this effect is pervasive and visible across a number of areas of our lives, from poor uptake of pension plans through to exercising adequately, it is easy to see how initiatives using education or persuasion to encourage more complex behaviours might not be enough to overcome our innate inclination towards behavioural lethargy.
Further, in both instances, horse owners across multiple studies discussed previously showed that both under-vaccinating and over-worming were framed as responsible behaviours; vaccinations are perceived as unnecessary intervention for horses not at risk, while horses wormed without FECs may be perceived as still being effectively protected from parasites. Therefore, messaging that seeks to educate owners may miss its mark if those owners feel they are already engaged in a “right” or “responsible” behaviour – particularly given their chosen behaviour is also the easiest option. To overcome this, one option is to make the “right” behaviour easier, for example by offering health plans, simplifying booking systems, using reminders and reducing costs as far as possible.
Additionally, making alternate behaviours more problematic can also facilitate behaviour change; for example, many countries have made anthelmintics prescription-only, adding an additional behavioural friction.
Updated competition, clinic and livery yard rules, which prevent the movement of horses that are not appropriately vaccinated or dewormed, might increase the uptake of preventive health measures.
The factors that determine whether horse owners comply with veterinary recommendations around parasite control and vaccination are complex, and different owners will have different motivators.
Having an understanding of the drivers of human behaviour and an appreciation of how owners integrate veterinary advice (or not) into the management of their horses can help in breaking down barriers and improving engagement.
Yard managers and sporting bodies have a major role to play in encouraging appropriate preventive health and creating social norms around responsible behaviours; therefore, veterinary attention in working with these stakeholders may be an effective use of resources.
Whether communicating with horse owners directly or with other stakeholders, consistency of message and trust is essential in the development of veterinary-led health plans that are ideally population-based rather than focused on individual horses.
