Horses require a balanced diet with adequate forage to maintain health and behavioral norms.
A diet below 80% forage can lead to several behavioral issues.
Selection of forage types, such as high-fiber grasses over enriched grains, can promote better health outcomes in horses.
Grazing Behavior
Locomotion is crucial in grazing behavior as horses typically cover large areas, rarely consuming more than two mouthfuls at one spot before moving.
Stabled Horses: Constrained movement leads to distinct behavioral adaptations. Increasing locomotion mimics free-ranging behavior, which is beneficial for health.
Horses in larger areas of pasture exhibit increased speed and stride length while grazing, facilitating healthy behavior.
Track formation emerges in sloped pastures, guiding daily grazing paths; spacing depends on terrain incline.
Diet Management: Protocols that require horses to travel between feeding and watering stations in paddocks simulate free-ranging behaviors, which may confer health benefits, e.g., strengthening hooves.
Example of Grazing Behavior
Horses may paw at snow to access grass or roots or paw to break ice for water.
Anticipation of feeding is reflected in increased vocalizations and heart rate before feeding sessions, alongside a significant elevation in heart rate during meals.
Health Implications
Transient post-prandial hypovolemia occurs in horses fed large meals episodically, affecting blood flow to extremities.
Prolonged vascular responses, such as laminitis, may occur due to stabled horses not moving between bite-sized meals.
Social Dynamics and Feeding
Horses are social animals that benefit from group living, which increases vigilance against predators.
Spacing Strategies: Anti-predator strategies relate to herd size. For example, distance between Thoroughbred yearlings grows significantly with herd size, indicating a need for safety during feeding.
Social Facilitation: Grazing durations increase with group size; behavior varies by social structure (dominance hierarchies affect feeding).
Studies show stabled Shetland ponies benefit from visual contact with peers while feeding. Design features like feeding bays may optimize individual feeding experiences, reducing anxiety.
Nutritional Influences on Behavior
Horses on forage have a higher plasma serotonin level than those on grain, affecting demeanor and behavior.
Diets high in starch may induce 'hot' behavior, characterized by increased reactivity.
An example includes ponies showing less adverse reactions to changes in social or environmental context when on higher fiber diets.
Sleep Patterns and Diet
Diet Transition Effect: Switching from hay to oats briefly increases total sleep time, possibly due to physiological changes. However, normal patterns resume quickly.
Stress coping ability may also improve with dietary changes, particularly with the inclusion of fats and fibers.
Dysphagia, Anorexia, and Hypophagia
Dysphagia: Difficulty in swallowing may be caused by several conditions: trigeminal nerve injuries, esophagitis, stomatitis, etc.
Example symptoms include neck arching due to esophagitis or drooling in stomatitis cases.
Anorexia and Hypophagia: Reduced food intake often relates to social dynamics; subordinate horses may be outcompeted by dominants.
Environmental stressors like moving or loss of companions might also induce a lack of appetite, prompting a need for behavioral changes during stressful environments.
Hyperphagia
The tendency to overeat can lead to issues like colic; feeding schedules should accommodate horses' natural feeding behaviors to avoid rapid eating.
Techniques for management include: providing adequate forage, reducing competition, and spreading feeding opportunities throughout the day to mimic natural conditions.
During fasting, post-prandial effects can escalate problems like gastric ulcers.
Abnormal Behavioral Patterns
Wood-Chewing and Bed-Eating
Common behaviors in horses restricted to stable feeding, indicative of stress or nutritional deficiencies.
Horses often consume non-food items due to dietary imbalances or boredom. Increasing fiber intake in diets can mitigate these issues.
Coprophagy and Geophagia
Normal behaviors in foals can become problematic in adults when linked with nutritional deficiencies. Horses have been noted to consume their own feces or that of conspecifics possibly to obtain additional nutrients.
Oral Stereotypies
Licking and crib-biting behaviors can lead to serious health concerns like dental erosion and colic. The management of these behaviors intersects deeply with dietary and environmental factors.
Crib-Biting and Wind-Sucking
Crib-Biting: Involves horses seizing fixed objects and makes a specific noise while ingesting air.
Wind-Sucking: Similar actions without the involvement of an object, leading to differing health implications and seemingly less direct oral motion.
Environmental Stressors: Approximately 10.5% of horses initiated crib-biting at a young age, especially when increasing concentrate feeds during weaning, creating a need for careful environmental management post-weaning.
Physiological Links
Increased plasma cortisol levels in crib-biters may align with observed weight loss in these horses due to fixation on this behavior rather than foraging.
Research indicates a potential link between dietary manageability and oral stereotypies, meaning interventions with diet can affect behavioral expression.
Treatment Protocols
Interventions include the use of collars to discourage crib-biting, though they often lead to increased behavior upon removal (post-inhibitory rebound). Surgical interventions have been explored but raise welfare concerns.
Treatment efficacy may also relate to addressing the underlying dietary and environmental causes of these behaviors.