# Horse Olfactory Exploration of Various Plants with Regard to Smell and Taste Familiarity

## TL;DR

Horses explore unfamiliar herbs more intensely, showing that prior smell and taste experiences influence their feeding behavior.

## Contribution

The study reveals how prior sensory experiences affect horses' olfactory exploration of plants.

## Key findings

- Horses explored least familiar herbs the longest, indicating neophobic behavior.
- Herbs known by smell and taste were explored the shortest, showing quicker recognition.
- Taste experience significantly influences olfactory recognition of plants.

## Abstract

The senses of taste and smell are important in food selection and acceptance. Horses may exhibit a neophobic response to a novel odour or flavour, and they usually show preferences for known feed. The current study investigated if previous experience with the smell and taste of herbal plants influences horses’ olfactory exploration of those plants. The horses were allowed to smell nine herbs, three of which were of the least level of olfactory familiarity for them, three were known only by smell, and the remaining three were known by smell and taste. Herbs were placed in a special crib that prevented them from eating the plants. The horses paid more attention to the least familiar herbs, as indicated by the longest exploration times (sniffing, licking, nibbling, touching the crib), whereas the herbs known by smell and taste were explored for the shortest time. The taste experience plays a significant role in the olfactory recognition of plants. Prior olfactory exposure to a plant can induce a comparably rapid response to that seen in the case of taste–olfactory experience. Geldings and warmbloods are more cautious when exposed to the scent of less familiar plants and rely more on a previous taste experience.

The sense of smell is the first sense by which horses determine the suitability of feed for consumption. The aim of the study was to assess the influence of the degree of familiarity with the smell and taste of plants on horses’ olfactory exploration. Behavioural responses of twenty adult horses to nine herbs of three degrees of familiarity—least familiar (unknown in the first trial), known only by smell, and known by smell and taste—were investigated. During the tests, the horses were allowed to explore the individual herbs placed in a crib constructed to prevent them from eating the contents. Horses’ pre-consuming behaviour towards olfactory cues of plants was mainly expressed by different times of exploration. The horses explored herbs known by smell and taste less intensively than those initially unfamiliar, but not less intensively than herbs known only by smell. Thus, having more sensory experience (taste and olfactory) with a plant in the past, horses are often quicker to recognise plants based solely on the sense of smell in the future. The sex and type of the horse (warmblood, pony) may influence responses towards herbs of different levels of familiarity.