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

Abstract

Highlights (for review):-The effect of odour, taste and nutrients on diet intake by horses was examined.-Two-choice and multiple-choice tests were used to evaluate feeding behaviour.-Nutrient content appeared to be the main driver for diet choices.-Taste appeared secondary to nutrients in determining the diet selected.-The multiple-choice test was able to more clearly differentiate in diet ranking. AbstractWhile it has been established that nutrients and flavours (odour, taste) play an important role in diet selection by horses, previous studies have not always clarified what type of flavouring (e.g. non-nutritive or nutritive) was used. Therefore, the objective of this study was to determine the influence of distinct food characteristics (odour, taste, nutrients) on the preference of horses using different preference testing protocols. This experiment consisted of three phases; adaptation (P1), two-choice testing (P2) and multiple-choice testing using a chequerboard design (P3). Four pelleted diets equal in digestible energy, but contrasted in crude protein (LP; 14% and HP; 27%) and added non-caloric (natural) sweetener (i.e. LP, LP+, HP, HP+) were consecutively fed to each of sixteen adult horses. The diets were paired with four non-nutritive odours (coconut, banana, cinnamon, spearmint), with a unique odour and diet combination allocated to each group of four horses. In P1, each diet was presented solely for five days to facilitate pre-and post-ingestive associations; in P2 a two-choice test was conducted with four diet combinations (contrasts) over three days; and in P3 the four diets were presented simultaneously in a checkerboard fashion over a 5-day period. Feed intake, bucket/zone visits and time spent foraging or moving were recorded. The key findings of this study were: (1) In P1 an initially large variation in intake was recorded with only some horses showing a neophobic response to a new odour/food, but variation declined within 2 days with the majority of the horses consuming over 90% of the diets. (2) Nutrient (HP) content appeared to be the main driver for diet intake in P2 (P<0.05) and P3 (P<0.001). (3)

Horses’ rejection behaviour towards the presence of Senecio jacobaea L. in hay

“…In the study by van den Berg et al ( 2016) nutrient content was mentioned as the most important criterion for food rejection in horses followed by the food's taste. Odour had the lowest effect on food intake [21]. In another study, van den Berg et al ( 2016) stated that a well-known non-nutritive odour like fresh lucerne reduced the neophobic effect in horses when lucerne odour was added to a novel food [22].…”

“…Furthermore, the findings of the studies previously mentioned demonstrated that horses had a greater preference for familiar diets and that horses showed a strong neophobic response towards unfamiliar diets. A discrimination based on macronutrient content required an adaptation period for at least three meals [21,23,24].…”

Palatability assessment in horses in relation to lateralization and temperament

“…In our trials, ponies tended to sample from both hay alternatives (flavoured and water) and to select an equal proportion of feed from both buckets, whenever new flavours were accepted. As reported by Van den Berg (2016a, 2016b, 2016d horses display patch foraging behavior sampling from all foods offered and an equal proportion of familiar and new feed eaten during multiple choice test (van den Berg et al, 2016d). The same authors showed also a similarity for the time spent walking towards different "forage zones".…”

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

“…Beside palatability or stimulating odour, adaptation periods to feedstuff seemed to be important in selection behaviour of horses. Several studies showed that horses preferred feeds with high content of proteins, carbohydrates (starch and sugar) or energy levels if they were adapted to these diets for at least three to five days or 10 feeding sessions (Cairns et al, 2002; Redgate et al, 2014; Van den Berg, Giagos, Lee, Brown, Cawdell‐Smith, et al, 2016). However, in our study, the intake of MS was mainly observed at the beginning of the experiment within the first two observation periods.…”