Acceptance of novel food by horses: The influence of food cues and nutrient composition

Abstract

Compared to ruminants little is known about how horses modulate food intake and learn about flavour-to-post-ingestive consequences. While it has been suggested that due to hindgut fermentation horse's foraging preferences may be largely influenced by sensory input (e.g. volatiles), it has been established that horses are able to differentiate and select familiar foods (e.g. concentrates and hay) based on nutritional content. Yet it remains unclear how this translates to the acceptance of nutritious novel foods (NF). Therefore, the influence of food cues and nutrient composition on NF acceptance were examined in two experiments using 11 adult mares. In experiment 1, we investigated the influence of a familiar odour (FO) on the acceptance of a nutritious NF and in experiment 2, we determined if horses have the ability to select nutritious NF based on the nutritional content, regardless of sensory preferences. In experiment 1 horses received identical NF in a two-choice test with one of the choices being masked with a FO over a 9-day period. In experiment 2 horses were offered a high or low protein option of an otherwise identical NF in a two-choice test in which the NFs were paired with two unfamiliar flavours (odours). The two-choice test lasted for 14 days and the flavour-protein pairing was switched after 7 days. NF intakes were recorded over a 10 min test period on each test day and analysed using Bayesian hierarchical models. The results of experiment 1 indicate that a FO had a strong positive influence on the NF intake for the first 5 days (90-100% of total consumption and strong evidence for nonzero temporal effects (Bayes factor B 12 =110)). This was followed by a more even distribution of intake for the remaining period. In experiment 2 horses had a greater intake of high protein NF regardless of the flavour on days 4, 6 and 7 (80-87% of total consumption) and this continued after the switch over (Day 9 to 14; 57-81% of total consumption). However, 4 out of 11 horses showed neophobia throughout the testing period, which could have been associated with the novel odours as horses scanned the buckets with little to no sampling. The results suggest that pre-ingestive cues (e.g. smell, taste) of foods play an important role in diet selection and that a FO can increase the acceptance of NF. This new knowledge could be applied by the horse industry to encourage the consumption of new food or forages by horses.

Palatability assessment in horses in relation to lateralization and temperament

“…According with van den Berg and Hinch (2016), an adaptation of 3-4 days seemed to be necessary to reduce the variability following the introduction of a new odour in horses. These results were in accordance with another study of the same researchers (van den Berg et al, 2016c). Similar conclusion were found by Hinch et al (Hinch et al, 2004) showing that the association of a novel feed (wheat) with a familiar odour or flavour (alfalfa) seemed to decrease the variability in intake and to increase the total intake of the novel feed compared to the control group.…”

The influence of odour, taste and nutrients on feeding behaviour and food preferences in horses

“…This difference was less evident when a sweetener was added to the diet, an observation supported by the mean intake measures showing a ranking based on protein content but there were no significant differences in intake for the LP+ and HP diets. A similar ranking was also recorded in the multiple-choice test and these findings are in accord with other studies that have reported that preferences and intake are linked to macronutrient content (Laut et al, 1985;Cairns et al, 2002;Goodwin et al, 2005a;Redgate et al, 2014;van den Berg et al, 2016b). Such studies demonstrate that horses can discriminate between diets based on both energy and CP content, even if foods are novel and regardless of flavour (odour) preferences.…”

Rejection behaviour of horses for hay contaminated with meadow saffron (Colchicum autumnale L.)

“…Sweet odour (banana, coconut) increased the forage intake in comparison with the same feedstuff without sweet odour (Van den Berg, Giagos, Lee, Brown, Cawdell‐Smith, et al, 2016). In another study, a familiar odour (fresh lucerne) has been shown to have a positive effect on the intake of a novel food in horses (Van den Berg, Giagos, Lee, Brown, & Hinch, 2016). Whether MS has such a sweet or familiar odour is unknown.…”

“…Not only the presence of secondary metabolites, such as bitter substances, may influence the taste of forages but also various studies have shown that horses prefer feeds rich in carbohydrates, such as sugars (Redgate et al, 2014), or high in protein (Rodiek & Jones, 2012; Van den Berg, Giagos, Lee, Brown, Cawdell‐Smith, et al, 2016; van den Berg et al, 2016; van den Berg et al, 2016). In the present study, MS had higher content of CP, NFE, such as sugars or starch, and CFAT compared to hay, which may relate to a high palatability of MS.…”