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

What the hay: predicting equine voluntary forage intake using a meta-analysis approach

To properly formulate diets, the ability to accurately estimate feed intake is critical as the amount of feed consumed will influence the amount of nutrients delivered to the animal. Inaccurate intake estimates may lead to under- or over-feeding of nutrients to the animal. Individual differences in equine forage intake are well-known, but predictive equations based on animal and nutritional factors are not comprehensive. The objective of the present study was to consolidate the current body of knowledge in the published literature on voluntary forage DM intake (VFDMI) in equines and conduct a meta-analysis to identify driving factors, sources of heterogeneity, and develop predictive equations. Therefore, a systematic literature search was applied and identified 61 publications which met the inclusion criteria. From each study, the outcomes of interest (e.g., forage intake), diet composition (e.g., forage information, nutrient composition), and animal factors (e.g., sex, age, breed, BW, exercise level) were extracted. Forage intake was analyzed as two different outcome variables: (1) VFDMI in kg/d and (2) VFDMI in g/kg BW. Linear mixed model analysis treating study as a random effect was applied, using a backward-stepping approach to identifying potential driving variables for VFDMI (both units) where all terms have P < 0.1. The best fitting models for VFDMI included similar factors (also across kg/d and g/kg BW) such as forage quality (i.e., neutral detergent fiber or CP content), forage type (i.e., grass, legume, or mixed), the animals' size category (i.e., horses vs ponies), and some management factors (i.e., pasture access). As anticipated, forage intake increased when higher quality forages were fed (i.e., lower neutral detergent fiber or higher CP), potentially due to improved digestibility. Additionally, VFDMI increased as BW increased but ponies increased their VFDMI more per every kg increase in BW compared to horses. Lastly, pasture access (i.e., grazing) may influence VFDMI such that pastured animals consume less than stalled animals, possibly due to the time it takes to graze forage. In conclusion, equations to predict equine VFDMI with high accuracy and precision (concordance correlation coefficient  = 0.82 - 0.95; root mean squared error RMSE = 0.82-5.49) were developed which could be applied in practice by equine nutritionists or owners and managers. The results of this meta-analysis confirm that animal traits and forage quality have a significant impact on the VFDMI of equines and should be accounted for when formulating diets to ensure nutritional requirements are met.

Impacts of olfactory cues on equine feeding behavior

Anise has demonstrated equine palatability but its olfactory effect is underexplored. The objective was to investigate the effect of the aroma of anise on consumptive behavior. Stock-type horses (n = 8) were used in a crossover 6-day preference test. Palatability stocks were utilized. Bowls containing oats were situated on plates holding gauze soaked with 0.375 ml of anise or corn oil (control). Variables included first diet sniffed (FS), first consumed (FC), first action (FA), and amount consumed (AC). Each trial was video-recorded. Behavior data were analyzed using chi square and Kruskal-Wallis tests. FS and FC were elevated for anise treatment (P = 0.02; P = 0.04). For FA, sniffing was more frequent versus consuming (P < 0.01). AC for anise was twice the daily average of control (P < 0.01). Data represents an important relationship between olfactory stimuli and feeding in horses. To determine thresholds, more work is needed.

Odor exploration behavior of the domestic pig (Sus scrofa) as indicator of enriching properties of odors

Introduction and aim

Although the sense of smell in pigs is widely recognized as being highly developed, surprisingly little is known about their sensory ability. This study aimed to (a) identify which non-social odors pigs were able to detect and distinguish between, (b) investigate the types of behavior expressed when exploring odors and, (c) compare pigs' responses to the different odors to evaluate their interest in the odors.

Methods

Growing pigs (N = 192) of crossbred commercial breeds were enrolled in the experiment (32-110 days of age, weighing 64.9 ± 10.1kg). Littermate pairs of opposite sex were tested in test pens with two odor insertion points in the pen wall, 55 cm apart. All pigs were habituated to the test pens and experimenters. Twelve odors were tested (eight essential oils and four synthetic perfumes) in groups of three odors, with each pig pair tested once with one set of three odors (all possible orders of the three odors were tested on 24 pairs in total), always against a non-odor control (demineralized water). In a test, each of the three odors were presented during three trials in a row (a total of 9 trials per test; trial duration: 1 min; inter-trial breaks: 2 min; total test duration: 25 min). Response variables included: duration of sniffing, feeding-related behavior (licking, biting and rooting), agonistic behavior (biting, displacement and pushing) and no approach of the odor or control, recorded throughout each 1-min odor presentation.

Results

All pigs sniffed an odor less when repeatedly presented (LMM: all odors P < 0.05), and significantly longer at the subsequent presentation of a new odor [LMM (3rd vs. 1st presentations): P < 0.001]. Specific odor and odor type (essential oil vs. synthetic perfume) had no significant effect on sniffing duration. Overall, feeding-related behavior and agonistic behavior were expressed significantly more when pigs explored the odor compared with the control insertion point (Paired t-tests: P < 0.001), and specific odor only affected the expression of feeding-related behavior.

Conclusion

Collectively, pigs express sniffing, agonistic, and feeding-related behavior when exploring odors, which suggests that pigs perceive odors of non-social origin as a resource. Odors may thus constitute relevant enrichment material for pigs.

Diet Preference, Feed Efficiency and Expression of the Sodium-Dependent Glucose Transporter Isoform 1 and Sweet Taste Receptors in the Jejunum of Lambs Supplemented with Different Flavours

This study investigated the effect of dietary flavour supplements on the preference, feed efficiency and expression of the sweet taste receptor family 1 members 2 and 3 (T1R2 + T1R3), and sodium-glucose linked transporter 1 (SGLT1) genes in the lambs' small intestines. Eight, five-month-old, Israeli crossbred Assaf lambs were offered 16 different non-nutritive commercial flavours in rolled barley and ground corn. Capsicum and sucram were the most preferred non-aroma flavours (p = 0.020), while milky (p < 0.001) was the most preferred powder-aroma flavour. For the metabolic and relative gene expression study, eight lambs were randomly assigned to either sucram, capsicum, a mix containing sucram and capsicum at 1:1 ratio or no flavour for control in a 4 × 2 cross-over design. The total collection of urine (females only), faeces and refusals was carried out, and T1R2, T1R3 and SGLT1 relative gene expression evaluated from the proximal jejunum biopsies. Flavour had no significant effect on the feed intake (p = 0.934), but capsicum increased the average daily weight gain per metabolic body weight (p = 0.049). The T1R3 gene was expressed highest in the mix treatment (1.7; p = 0.005). Collectively, our findings indicate that flavours can be used to motivate feed acceptance and improve the weight gain in lambs.

Carbohydrate pellets to assess insulin dysregulation in horses

BACKGROUND

A glycemic challenge test is used for the diagnosis of insulin dysregulation (ID) in horses and ponies. Different forms of the test exist where the administrative route and dose of glucose vary, which makes interpretation of results challenging.

HYPOTHESIS/OBJECTIVES

To evaluate the palatability of, and blood glucose and insulin responses to, carbohydrate pellets fed as an oral glucose test (OGT), and to establish the diagnostic threshold for ID when using the pellets.

ANIMALS

University and privately-owned horses and ponies (n = 157) comprised of 31 breeds and both sexes.

METHODS

Multicenter cohort study. A custom-produced glycemic pellet was offered for free intake at 0.5 g/kg BW soluble carbohydrate and serum insulin and blood glucose concentrations measured before and after (60, 120, and 180 minutes) the pellets were offered. Pellet acceptance and intake time (those that finished within 10 minutes) were determined to assess palatability.

RESULTS

The pellets were palatable to 132/157 animals, and ponies found the pellets more (P = .004) palatable than horses. The median intake time (4 [3-6] minutes) was positively correlated with acceptance grade (r = .51; P < .0001). Consumption of the pellets elicited peak blood glucose (6.6 [5.8-7.8] mmol/L) and serum insulin (40.5 [19-99.8] μIU/mL) responses at 120 minutes. At 120 minutes the optimal cut-off was 83 μIU/mL (95% CI: 70-99 μIU/mL) for the IMMULITE 2000XPi assay.

CONCLUSIONS AND CLINICAL IMPORTANCE

The pellets were palatable and a suitable, novel carbohydrate source for the OGT.

Influences of Oil- Based Palatants on Eating Behavior in Gestating Mares

Gustatory and olfactory changes have been reported during gestation in multiple species. However, few data are available regarding feeding preferences in gestating mares. The objective of this research was to evaluate the effect of oil-based palatants on feeding behavior in late term gestating mares. Late-term gestating mares (n = 5) and reproductively sound, open mares (n = 4) were evaluated via paired preference testing during the final 120 days of gestation. Oil-based flavors (corn oil, anise, and apple) were topically applied to a basal pelleted diet (0.375 ml/0.23 kg). Diets were offered simultaneously using a ground level feeding platform and individual box stalls with 20 minutes allotted for engagement. Behaviors assessed included: sniffing, hovering, checking, chewing, chewing with the head lifted, uninterested, ingestion, pawing, flipping of feed pan, moving of feed platform, and defecation. Variables of interest included: first diet sniffed, consumed, and finished; time to finish first diet; time to finish all diets, and number of olfactory and consumption engagements for each diet. Data were analyzed using PROC FREQ and PROC MIXED in SAS Studio. Data analysis revealed a faster rate of consumption for first diet finished (P = 0.05) of gestating mares when compared to open mares. Additionally, gestating mares had a greater frequency of olfactory interactions across all diets (P < 0.01), but less consumption interactions across all diets (P = 0.01). These novel data suggest a previously unreported increase in olfactory investigation for gestating mares as well as new insights into gestational feeding behaviors of horses.

Reinforcer efficacy of grain for horses

Positive reinforcement is becoming more common in horse training. Identifying effective reinforcers is critical for training success. The aim of this study was to determine relative reinforcer efficacy of different grains. Four horses learned to muzzle touch a target, after which they were tested using a progressive ratio schedule of reinforcement with different grains as the consequence. Break points were used to determine relative reinforcer efficacy of each grain and were also converted into unit price per kilocalorie to determine if caloric value impacted reinforcer efficacy. Condition 1 compared three textured grains that spanned industry-accepted standards of low to high nonstructural carbohydrate content. Condition 2 compared three pelleted grains that similarly differed in nonstructural carbohydrate content, comparable to Condition 1, but that had a different texture than those of Condition 1. Finally, Condition 3 directly compared one grain each from Conditions 1 and 2. Results showed overall little difference in reinforcer efficacy or unit price between grains but found that all grains tested functioned as reinforcers for the horses. This suggests that a range of commercially available grains can maintain behavior and therefore be used for training. We also identified possible extraexperimental factors that impact reinforcer efficacy.

Horses wait for more and better rewards in a delay of gratification paradigm

Self-control, defined as the ability to forgo immediate satisfaction in favor of better pay-offs in the future, has been extensively studied, revealing enormous variation between and within species. Horses are interesting in this regard because as a grazing species they are expected to show low self-control whereas its social complexity might be linked to high self-control abilities. Additionally, self-control may be a key factor in training and/or coping with potentially stressful husbandry conditions. We assessed horses' self-control abilities in a simplified delay of gratification test that can be easily implemented in a farm setting. In Experiment 1, we gave horses (N = 52) the choice between an immediately available low-quality reward and a delayed high-quality reward that could only be obtained if the horse refrained from consuming the immediate reward. Different experimenters (N = 30) that underwent prior training in the procedures, tested horses in two test phases either with their eyes visible or invisible (sunglasses). Twenty horses waited up to the maximum delay stage of 60 s while all horses performed worse in the second test phase. In Experiment 2, we improved the test procedure (i.e., one experimenter, refined criterion for success), and tested 30 additional horses in a quality and quantity condition (one reward vs. delayed bigger reward). Two horses successfully waited for 60 s (quality: N = 1, quantity: N = 1). Horses tolerated higher delays, if they were first tested in the quantity condition. Furthermore, horses that were fed hay ad libitum, instead of in a restricted manner, reached higher delays. Coping behaviors (e.g., looking away, head movements, pawing, and increasing distance to reward) facilitated waiting success and horses were able to anticipate the upcoming delay duration as indicated by non-random distributions of giving-up times. We found no correlations between owner-assessed traits (e.g., trainability and patience) and individual performance in the test. These results suggest that horses are able to exert self-control in a delay of gratification paradigm similar to other domesticated species. Our simplified paradigm could be used to gather large scale data, e.g., to investigate the role of self-control in trainability or success in equestrian sports.

Horses’ Response to a Novel Diet: Different Herbs Added to Dry, Wet or Wet-Sweetened Oats

Simple Summary

The commercial horse feed industry uses palatants to mask undesirable tastes of feed and enhance consumption. However, an unknown smell or taste may also hinder feed intake, due to, among other aspects, novelty. The acceptability of herbs by horses has not been studied. We analysed whether five herbs (field mint, common yarrow, common chamomile, common sage and common nettle) added alternately to oats and presented within a dry, wet or wet-sweetened diet influence horses’ willingness to consume. Twenty horses were given different diet combinations of a feed presentation and a herb consecutively, once daily. Seven parameters showing the willingness to consume were measured: times of olfaction and consumption, times and numbers of intervals in consumption and drinking water, and mass of leftovers. The results show that the herbs in the amount offered did not influence the time of intake and only the dry oats with common sage added were smelled longer before consuming. However, wetting or wetting and sweetening the feed increased the willingness to eat. In conclusion, herbs in small amounts do not affect the feed intake, whereas wetting and sweetening the diet is of great importance and should be regarded when preparing horse diets.

Abstract

The commercial horse feed industry uses palatants to mask undesirable tastes of feeds and enhance product acceptance. However, an unknown odour or taste may also hinder feed intake, due to, inter alia, novelty. The objective of the study was to assess the horses’ response to novel diet: five different herbs added alternately to dry, wet or wet-sweetened oats. Twenty adult horses were given different diet combinations of a feed presentation and a herb: field mint, common yarrow, common chamomile, common sage and common nettle, consecutively, once daily. The response to novelty was assessed regarding traits showing the willingness to consume: times of olfaction and consumption, times and numbers of intervals in consumption and drinking water, and the mass of leftovers. The results show that properties of the herbs studied did not hinder the consumption and only the odour of the dry common sage delayed the intake. Wetting or wetting and sweetening the diet accelerated the intake. In conclusion, herbs in small amounts do not significantly affect the willingness to consume feed. Although wet and wet-sweetened diet presentations may be novel to horses, they increase the feed palatability and can be suggested for use when preparing horse diets.

Sensitivity of ponies to sodium in the drinking water

Horses lose high amounts of Na through excessive sweating. These fluid losses can often not be replaced completely by voluntary water intake, requiring saline solutions as rehydration therapy to regain electrolyte balance. The experiment aimed to evaluate the sensitivity and tolerance of Shetland ponies towards different Na concentrations in their drinking water and contained three phases: (1) control: only fresh water provided; (2) pairwise-preference test: choice between fresh water and saline solution with stepwise increasing sodium chloride (NaCl) concentration (0.25%, 0.5%, 0.75%, 1.0%, 1.25%, or 1.5%); and (3) free-choice test: six simultaneously provided buckets containing NaCl concentrations of 0%, 0.25%, 0.5%, 0.75%, 1.0%, or 1.25%. During the pairwise test, the ponies did not distinguish between fresh and 0.25% NaCl-water but demonstrated clear preference for 0.5%, whereas >0.75% NaCl was avoided/rejected. During the free-choice test, a pronounced preference of fresh over saline water was exhibited. The Na intake via salt lick was not reduced as response to higher Na intakes via water. The ponies exhibited a remarkable sensory discrimination capacity to detect different NaCl concentrations in their drinking water. The acceptance of solutions with low NaCl levels (0.25/0.5%) without adverse effects demonstrates potential as rehydration solution for voluntary intake.

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

BACKGROUND

Senecio jacobaea contains pyrrolizidine alkaloids that can induce severe hepatic intoxication in horses, either acute when ingested in high amounts or chronic when consumed over a long period. The aim of this study was to determine horses' rejection behaviour towards the presence of Senecio jacobaea in hay when fed ad libitum. We hypothesized that adult horses can sort Senecio jacobaea out of the contaminated hay when hay is fed ad libitum. Six warmblood geldings with a mean (±SD) age of 15 ± 2 years were included. In a randomized study, Senecio jacobaea contaminated hay (5% or 10% contamination level) was provided at several timepoints over the day for 1 hour to six. Hay was provided ad libitum for the rest of the day. The horses' rejection behaviour towards Senecio jacobaea was observed. If a horse ingested two Senecio jacobaea plants twice at different timepoints, then the horse was excluded from the experiment.

RESULTS

Two out of six horses had to be excluded from the study after three out of 12 observation periods due to repeated Senecio jacobaea intake. Two other horses had to be excluded after nine and 11 out of 12 observation periods. Only two horses were able to sort out the various amounts (5 and 10% contamination level) of Senecio jacobaea during the whole experiment.

CONCLUSIONS

Horses' intake of Senecio jacobaea cannot be avoided despite being fed with hay ad libitum. Due to the risk of chronic intoxication by pyrrolizidine alkaloids intake, feeding Senecio jacobaea contaminated hay must be avoided, and pastures with Senecio jacobaea growth are considered inappropriate for feed production.

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

BACKGROUND

Extensively used grasslands are frequently utilised for hay production for equines. Especially, extensive meadows have a great variety of plant species, which may include plants that are poisonous for equines such as meadow saffron (Colchicum autumnale L.). To authors' knowledge investigations about horses` avoidance behaviour towards dried meadow saffron in hay are missing. Reports of farmers are contrary to clinical symptoms described in case reports and associated with meadow saffron in hay.

OBJECTIVES

The aim of this study was to determine the rejection behaviour of horses for hay contaminated with meadow saffron (MS) when fed ad libitum.

STUDY DESIGN

An 18-day feeding trial with six adult geldings to observe the rejection behaviour for hay contaminated with MS.

METHODS

The horses were fed a basal diet containing hay ad libitum and a mineral supplement during the feeding trial. At six different daytimes, hay contaminated with 1% or 2% dried MS was provided to the horses over a duration of 1 h. The rejection behaviour was observed personally and by video recordings. If a horse ingested more than two plants of MS during one observation period, the observation was stopped and repeated at another day. When the observation period had to be stopped twice, the horse was excluded from the experiment.

RESULTS

Five of six horses ingested MS during the first feeding periods. One horse rejected leaves and capsules at the beginning of the study, but it showed repeated ingestion of MS after the seventh observation period.

MAIN LIMITATIONS

Lack of knowledge about secondary plant metabolites affecting taste and their variability between fresh and dried plants.

CONCLUSIONS

The intake of MS in hay by horses could not be ruled out with certainty. Therefore, feeding hay contaminated with MS should be avoided for equids.

Palatability of Horse Treats: Comparing the Preferences of Horses and Humans

Despite its importance to product development, few data compare preferences for horses with human consumers. The objectives of this research were to compare treat preferences of horses against horse owners. Product A was a disk-shaped cinnamon-flavored flax-based treat, and product B was a textured apple-flavored oat-based treat. Horses were presented with two treat products in a paired preference test which comprised separate olfaction and consumption periods. Consumers evaluated the treats separately for purchase intent as well as hedonic testing of sensory attributes. No difference was observed for first product sniffed, consumed, or finished during the horse preference test. However, moderate positive correlations were observed between first product sniffed and consumed (P = .01, ф = 0.40) as well as first product consumed and finished (P < .01, ф = 0.48). Horse owners rated product A lower in appearance, texture, size, and purchase intent (P < .01) than product B. These results indicate that consumer testing for animal food should be considered during product development.

The Influence of Packaging on Palatability and Shelf Life Stability of Horse Treats

Horse treat packaging may be composed of materials including plastic and paper which protect the product from the environment to improve shelf life. Objectives of this research were to 1) assess the impact of packaging on shelf life of horse treats and 2) evaluate the impact of packaging on horse preferences. Three packaging treatments (control, poly, and paper) were examined at five time points over a 12 month period. Treatments were analyzed for moisture, water activity, mold, yeast, pH, and volatile organic acids. Horse preference testing evaluated first treatment sniffed, consumed, and finished as well as number of treats consumed. Significance was set at P < .05 and trends at P < .10. Moisture content and water activity increased in all treatments (P < .01) from month 0 to month 12, with paper packaging providing a greater fluctuation and containing visible mold at month 12 (P < .01). No difference was observed for first treatment sniffed, consumed, or finished during preference testing. However a trend (P = .09) for the period∗treatment interaction was observed for number of treats consumed, with poly increasing while paper decreased. These data indicate that packaging impacts shelf life and horse preference of treats.

Sensory Abilities of Horses and Their Importance for Equitation Science

Vision, hearing, olfaction, taste, and touch comprise the sensory modalities of most vertebrates. With these senses, the animal receives information about its environment. How this information is organized, interpreted, and experienced is known as perception. The study of the sensory abilities of animals and their implications for behavior is central not only to ethology but also to animal welfare. Sensory ability, perception, and behavior are closely linked. Horses and humans share the five most common sensory modalities, however, their ranges and capacities differ, so that horses are unlikely to perceive their surroundings in a similar manner to humans. Understanding equine perceptual abilities and their differences is important when horses and human interact, as these abilities are pivotal for the response of the horse to any changes in its surroundings. This review aims to provide an overview of the current knowledge on the sensory abilities of horses. The information is discussed within an evolutionary context and also includes a practical perspective, outlining potential ways to mitigate risks of injuries and enhance positive horse-human interactions. The equine sensory apparatus includes panoramic visual capacities with acuities similar to those of red-green color-blind humans as well as aural abilities that, in some respects exceed human hearing and a highly developed sense of smell, all of which influence how horses react in various situations. Equine sensitivity to touch has been studied surprisingly sparingly despite tactile stimulation being the major interface of horse training. We discuss the potential use of sensory enrichment/positive sensory stimulation to improve the welfare of horses in various situations e.g. using odors, touch or sound to enrich the environment or to appease horses. In addition, equine perception is affected by factors such as breed, individuality, age, and in some cases even color, emphasizing that different horses may need different types of management. Understanding the sensory abilities of horses is central to the emerging discipline of equitation science, which comprises the gamut of horse-human interactions. Therefore, sensory abilities continue to warrant scientific focus, with more research to enable us to understand different horses and their various needs.

Equine atypical myopathy: consumption of sycamore maple seedlings (Acer pseudoplatanus) by pastured horses is driven by seedling maturity and might be associated with phenolic compounds

BACKGROUND

Poisoning with Acer pseudoplatanus L. in horses contradicts the hypothesis of coexistence between plants and vertebrate herbivores being mediated through antipastoral traits as toxins. However, incidental observations showed that horses evaded Acer seedlings with primary leaves. The objective of the present cross-discipline study was (i) to analyse whether developmental stages of A. pseudoplatanus L. differed as to phenolics hypothesised as antipastoral traits, and (ii) to observe systematically the selection behaviour of pastured horses towards A. pseudoplatanus seedlings.

METHODS

Phenolic profiles of five developmental stages from fruits to seedlings of progressing age up to adult leaves of A. pseudoplatanus and Acer campestre L. were characterised. Video recordings of grazing behaviour of 29 pastured horses towards seedlings of A. pseudoplatanus resulted into 117 sequences as additional field data.

RESULTS

The horses ingested 19.1 per cent of juvenile seedlings with cotyledons (1.65 mg total phenolics/g fresh weight (FW), 82 compounds, 0.02 mg total gallic acid/g FW) yet only 5.46 per cent of older seedlings with primary leaves (8.48 mg total phenolics/g FW, 120 compounds, 3.13 mg total gallic acid/g FW).

CONCLUSION

Horses distinguished between seedlings in distinct stages that could be chemically distinguished, too. Acer seedlings with primary leaves provide a strong, but not complete antipastoral effect that correlates with dramatic changes in phenolic compounds.

Nutrient content changes from steaming or soaking timothy-alfalfa hay: effects on feed preferences and acute glycemic response in Standardbred racehorses1

Soaking hay and steaming hay are strategies that are used to reduce respirable dust particles for horses but may result in variable nutrient losses, including nonstructural carbohydrates (NSC) and minerals. Since these losses have not been quantified in Canadian hay yet, the first aim of this study was to identify nutrient losses from first-cut timothy-alfalfa hay grown in southern Ontario, Canada, after soaking for 30 min or steaming for 60 min. It is uncertain whether horses prefer hay when it is dry, soaked, or steamed. To address this, 13 Standardbred racehorses were offered 2 of these hays side by side for 30 min on 6 consecutive occasions until all possible combinations had been offered. Quantity of hay eaten was determined and horses were video recorded during feedings to assess time spent eating and investigating hay. Additionally, consumption of feeds with differing NSC levels has been observed to influence glycemic response in horses; however, this has not been measured in horses consuming steamed hay before and the results from soaked hay studies have been inconclusive. As such, the final aim of this study was to examine acute glycemic response in horses after being fed dry, soaked, and steamed hays. Blood glucose was measured every 30 min from 9 Standardbred racehorses for 6 h following a meal of 0.5% of their body weight of treatment hay on a dry matter basis (DMB). Soaked, but not steamed, hay had lower concentrations of soluble protein, NSC, and potassium in contrast to the same dry hay (P < 0.05). Peak glucose, average blood glucose, total area under the curve, and time to peak did not differ among treatments (P > 0.05). We conclude that acute glycemic response of racehorses was not influenced by soaking or steaming hay. Horses also consumed less soaked hay (DMB) than dry or steamed hay (P < 0.05) and spent less time eating soaked hay than dry or steamed hay (P < 0.05).

Preference of Boer goats for Namibian native forage legumes and Lucerne (Medicago sativa)

The objective of this study was to determine the relative palatability of four native forage legumes (Otoptera burchellii, Crotalaria argyraea, Crotalaria podocarpa and Vigna lobatifolia) in comparison with each other and with Lucerne (Medicago sativa). Eight weaned Boer goats aged 6 months and weighing 25.2 ± 4.9 kg were grouped by sex, and then randomly allocated to individual pens. Goats were simultaneously offered 100 g of each of the four native legumes and 600 g of M. sativa (as-is basis) over a 10-day period. Grass hay (Cenchrus ciliaris), fresh water and mineralised salt licks were available at all times. Grass hay was given to allow diet mixing and possibly ameliorate any undesirable effects, such as bloat, due to feeding on legumes alone. The percentage of each species consumed of that offered was associated (P &lt; 0.001) with legume species, day and legume × day interaction. Over 95% of the O. burchellii, V. lobatifolia and Lucerne offered were consumed from Days 1 to 10. The amounts of Crotalaria spp. consumed fluctuated widely in the first 4 days, but increased thereafter to &gt;95% of that offered. This study demonstrated that hay of all the four native forage legume hays were palatable to Boer goats, with the inferred ranking being: (Lucerne, V. lobatifolia) &gt; O. burchellii &gt; Crotalaria spp. Further studies are required to investigate the productivity of goats feeding on these native forage legumes, which have potential for use in marginal lands.

Taste Preferences of Horses in Relation to Their Breed and Sex

The aim of this study was to determine the taste preferences of horses in relation to their breed and sex. Forty-eight adult purebred Arabian, Anglo-Arabian, Polish Konik, and Polish cold-blooded horses-stallions and mares in equal numbers-were examined in the study. During the experiment, five types of industrially processed feeds based on oats and natural dried products commonly regarded as horse treats (i.e., sour and sweet apples, carrots, sugar beet molasses, and barley with salt) were given to horses in buckets on three consecutive days. The behavior of the horses during the experiment was evaluated, as was the way in which they expressed their taste preferences, the sequence in which they consumed the pellets, the time they took to become interested in the pellets, and the time they took to consume each kind of pellet. The taste preferences of the horses were found to depend on their breed and sex. Pellets containing molasses were consumed more willingly by mares than stallions. Feeds with the addition of apples or carrots were the favorite treats of all tested breeds. The greatest variety in pellet taste preferences was found in purebred Arabian horses. Pellets with a distinct sweet taste or slightly salty cereals should be given to horses if other options are not available. In most cases, these two additions were chosen last by the horses in the experiment. Primitive horses had a distinct manner of expressing taste sensations. Horse behavior indicating an interest in a feed should not be taken as a proof of its tastiness. The first food chosen is not necessarily the one consumed most quickly.