Development and consistency of fearfulness in horses from foal to adult

Exploring factors that influence the behavior response to novel object tests in young thoroughbred horses: investigating sex, test site and auction history

Introduction

The novel object test is one of the three most common fear tests in veterinary science and employed in several different species. Although having been applied in several different studies in horses, it is surprising that there is no standardized test procedure available for these kinds of tests.

Methods

This study investigated the performance of the novel object test on 42 young Thoroughbred horses to determine the effect of sex (mare or stallion), test sites (round pen or paddock) and whether the horses had previously participated in an auction or not on the behavior during the novel object test.

Results

Differences in horses' behavior during the novel object test were primarily attributed to the test sites. The animals showed significant (p < 0.05) intra-individual differences in the novel object test in the round pen and in the paddock. Sex did not affect the direct interaction with the novel object. The horses that had not participated in an auction seemed to actively perceive the novel object more quickly, so that the latency to first fixation on the object was significantly shorter.

Discussion

In order to obtain comparable results, it is recommended that novel object tests should be performed at the same location and under identical conditions. Furthermore, it is important to consider the individual behavior of each horse.

The effect of the fat to starch ratio in young horses' diet on plasma metabolites, muscle endurance and fear responses

High-starch diets may affect equine hindgut microbiota and increase blood glucose levels, which may cause unwanted physiological changes, but may also elicit behavioural changes such as increased fear reactions. The purpose of the current study was to feed a high starch (300) and low fat (43; HS_LF) or a low starch (60) and high fat (85; LS_HF, g/kg of DM) concentrate within the available commercial range and investigate how muscle endurance and fear reactions of horses respond to different diets. Twenty Danish Warmblood stallions (4 years) were randomly allocated to two treatments: LS_HF (n = 10) and HS_LF (n = 10) for 9 weeks. During the two last weeks, a single step exercise test was performed, and plasma metabolites and blood gases were measured before and after exercise in a 2 × 2 factorial design. The effect of two diets on fearfulness was tested by exposing the horses to novel objects test (T1 and T2). Plasma metabolites was not affected by diets. However, plasma level of glucose post-exercise (4.9) was lower than pre-exercise (5.6 mmol/L; p < 0.001). Similarly, plasma level of insulin post-exercise (4.2) was lower than pre-exercise (13.1 pmol/L; p < 0.001). Plasma level of lactate dehydrogenase (p < 0.001), non-esterified fatty acids (p = 0.002), β-hydroxybutyrate (p = 0.001), and fructosamine (p = 0.01) post-exercise was higher than pre-exercise. Regardless of type of diets, RRR-α-tocopherol was the dominance α-tocopherol stereoisomers in plasma. In conclusion, during aerobic exercise, fat to starch ratio in horse diets within the normal range had no significant effect on plasma metabolites. However, horses fed LS_HF tended to show more investigative behaviour than horses fed HS_LF.

Animal affect, welfare and the Bayesian brain

According to the Bayesian brain hypothesis, the brain can be viewed as a predictive machine, such that predictions (or expectations) affect how sensory inputs are integrated. This means that in many cases, affective responses may depend more on the subject's perception of the experience (driven by expectations built on past experiences) rather than on the situation itself. Little research to date has applied this concept to affective states in animals. The aim of this paper is to explore how the Bayesian brain hypothesis can be used to understand the affective experiences of animals and to develop a basis for novel predictions regarding animal welfare. Drawing from the literature illustrating how predictive processes are important to human well-being, and are often impaired in affective disorders, we explore whether the Bayesian brain theories may help understanding animals' affective responses and whether deficits in predictive processes may lead to previously unconsidered welfare consequences. We conclude that considering animals as predictive entities can improve our understanding of their affective responses, with implications for basic research and for how to provide animals a better life.

Effects of weaning-related stress on the emotional health of horses-A scoping review

BACKGROUND

Weaning represents one of the most stressful events in the life of a horse, and may have long-term impacts on behaviour. There are a range of approaches used to wean foals from mares, including abrupt and progressive separation methods. There is currently a lack of consensus on how stress and impact are measured.

OBJECTIVES

To conduct a scoping review to identify and chart measures of weaning-related stress on the mare and foal.

STUDY DESIGN

Scoping review.

METHODS

The scoping review was conducted using the PRISMA extension for scoping reviews. Systematic searches were conducted in three scientific databases (CAB abstracts, Medline and Embase). The title, abstract and full text of retrieved studies were reviewed against inclusion and exclusion criteria. Publications that remained after full text review were analysed. Data on study design, population characteristics, weaning method and health and behavioural outcomes were extracted and charted.

RESULTS

A total of 366 publications were identified; 22 were retained for inclusion and charting. Eighteen studies reported behavioural measures, four only reported physiological measures and 12/22 studies used a combination of both. Fifteen studies analysed foal behaviour only (15/22), six analysed foals with their dams and one analysed the mare only. Duration of most studies (19/22) was a maximum of 12 months post weaning; three studies continued measurements until the foal age was 3-4 years old.

MAIN LIMITATIONS

Limited number of studies available for analysis.

CONCLUSIONS

There is significant variation in the current evidence around weaning-related impacts in the mare and foal. This includes variation in how weaning methods and management of mares and foals are described, and very limited research evaluating long-term impacts, or the impact on the mare. This scoping review makes recommendations on how to improve the future evidence base.

Horse Owners' Knowledge of Fundamental Care and their Perceptions on the Implementation of a Mandatory Certificate of Knowledge

The aims of this study were to first determine the extent of owners' fundamental knowledge of equine care, second, gain their opinions on the implementation of a mandatory certificate of knowledge and third, to investigate the association of certification on horse owner knowledge. An online survey comprising 23 questions (18 closed, 5 open) was distributed worldwide via snowball sampling, and completed by 1847 horse owners who were all ≥18 years old from 17 different countries. Almost all (96%, n = 1781) completed surveys were usable. Just over half (52%) of participants held a current equine knowledge certification, and 59% believed a mandatory certificate of knowledge should be necessary to buy, own, or sell a horse. Horse owners with an equine certificate of knowledge were more likely to be in favor of a mandatory certificate (Pearson's Chi-squared = 50.79, df = 1, p < 0.0001). The mean correctly answered knowledge questions was 68%, indicating that approximately 1/3 of horse owners lacked fundamental horse care knowledge. Further examination indicated that participating horse owners showed the least understanding in the behavioral interactions domain (ANOVA F(4, 24) = 4.98, p < 0.01), specifically in relation to pain recognition and learning theory terminology. Arguably, this deficit in knowledge and likely correct application increases the risk of owners using misinformed or inappropriate techniques to manage horse behavior and training, predisposing the horse to experiencing a sub-optimal quality of life. Overall no significant difference was found between the total correct scores of horse owners with or without a certificate (ANOVA F(1, 56) = 0.78, p > 0.05); however, a series of Chi-squared tests revealed that for the more complex questions, horse owners with a certificate scored better than those without (all p < 0.05). Further work is needed to develop an evidence-based assessment framework if mandatory certification of horse owners is to become an effective tool for improving horse welfare and quality of life.

Heterospecific Fear and Avoidance Behaviour in Domestic Horses (Equus caballus)

Ridden horses have been reported to be fearful of cows. We tested whether cows could provoke behavioural and cardiac fear responses in horses, and whether these responses differ in magnitude to those shown to other potential dangers. Twenty horses were exposed to cow, a mobile object or no object. The time spent at different distances from the stimulus was measured. In a separate test, heart rate (HR), root mean square of successive differences between heartbeats (RMSSD) and the horses' perceived fear were assessed at various distances from the stimuli. The horses avoided the area nearest to all stimuli. During hand-leading, the cow elicited the highest HR and lowest RMSSD. Led horses' responses to the cow and box were rated as more fearful as the distance to the stimulus decreased. Mares had a higher HR than geldings across all tests. HR positively correlated with the fearfulness rating at the furthest distance from the cow and box, and RMSSD negatively correlated with this rating in cow and control conditions. Our results show that these horses' avoidance response to cows was similar or higher to that shown towards a novel moving object, demonstrating that potentially, both neophobia and heterospecific communication play a role in this reaction.