When comparing the behavior of wild animals and livestock in a production setting there are many behaviors that have remained the same over the course of domestication, as well as, many behaviors that occur that previously were unobserved in the species. Using Equus as an example, I will summarize the general feeding behavior of the wild horse and compare this to the feeding behavior of the domesticated horse to reveal possible issues caused by production management and discuss the way the problems may be alleviated.
Wild horses on an open range will consume grasses, forbs, and browse. The horses may also utilize mineral licks, as well as, participate in coprophagy, the ingestion of feces to achieve required nutrition. There are no restrictions to their foraging and the seeking and consuming of quality forages in the wild causes great time expenditures. The consumption of these forages requires the mechanical action of retrieval, requiring a portion of energy as the action is carried out. Energy becomes a larger factor when considering that these herds selectively graze which requires frequent movements. While a group of mares naturally lead a harem of horses in the direction of forages and water a stallion will take lead if there is a safety concern.
Horses are a prey species and must maintain an alertness in the wild. Their natural existence is in a harem within a herd. Horses are naturally social and in so find comfort in the presence of others when dominance has been previously established. Despite a need to retain their safety from predators, the ability to forage 24 hours a day offsets the need to ingest forages at a faster rate. It has been shown that restriction of time at pasture increases dry matter intake in the domesticated horse (Dowler, Siciliano 2009). Foraging in the wild is carried out at the desire of each individual when the opportunity has arisen and natural behaviors related to feeding are not discouraged by anyone outside of the harem except predators.
Horses that are part of the production setting are under supervision and their diet supplied. These diets may differ drastically. A large part of this is the carbohydrate and protein sources that are provided. Foodstuffs are often quick and easy to consume and when given in larger quantities can lead to picking through the feedstuff for the more desired components. Grains are high energy sources. Hay may be supplemented with other feedstuffs when a horse is stalled. The required vitamins and minerals, as well as water, is all provided. The ability to naturally exercise and feed on fresh sources of nutrients is denied to the stalled horses. Their exercise is widely dependent on the actions of their owner or caretaker which is dependent on what use the horse serves.
Energy reserves may not be spent accordingly. Horses that are set out to pasture have the ability to forage like their ancestors of the wild, although the experience of foraging can vary as the size of pasture, quality of plant life, and exposure to other horses present can spread across a wide range. In a study comparing feral horses to domestics, it was observed that there was actually a higher level of aggression in paired feeding tests of the domesticated horses.(Houpt, Keiper 1982).
Horses that are required to seek out their nutritional requirements in the wild are exposed to a range of forages that provide an extensive variety of nutrients whereas the nutrients provided by man for the domesticated horse has been formulated but far from match the variety of the wild or the require great physical means to do so. Differences are more evident in horses that are not regularly exposed to a pasture setting. The preparation of feedstuffs by man has drastically reduced the time required within appetitive and consummatory stages of behavior in obtaining food resulting in extensive time and energy surpluses.
The retention of energy may lead to a heightened or pent up feeling by the horse. This situation is also often blamed for some of the stereotypies known to horses such as cribbing and stall kicking. These behaviors may be of concern as the time and effort spent on these unfruitful activities may interfere with the execution of other life requirements such as rest or feeding. During cribbing bouts aerophagia, swallowing of air, occurs. This activity can lead to dangerous conditions in the horse and management protocol is to eliminate this behavior. Efforts to curb this behavior in cases can include a cribbing strap or shock collar to prevent the activity.
In extreme cases surgery and pharmacology is utilized. (Houpt, McDonell 1993). Scientists are now considering that some behaviors may be caused by an equivalent to the human Tourette Syndrome as pharmacologic treatments in the human show promising results in the horse (Dodman et al., 2009). Tourette Syndrome not being fully understood leads to a consideration of environmental triggers in the disease. With the knowledge of a genetic linkage that is involved we could make better decisions in selective breeding. It can also be speculated that the occurrence of stall kicking is a learned process of the horse conceiving that the action is the source of a feeding reward when carried out in that order. When attempting to curb this behavior the allotment of food has to be dispensed in a reverse way where the horse is not fed after the bout of stall kicking and is actually fed small portions when the actions are not exhibited (Houpt, 1981)
Behaviors in the horse may not be immediately exhibited after the original stimuli. In the case of diets and energy surplus a solution must be obtained as both of these behaviors can be dangerous causing colic like symptoms caused by aerophagia and injuries to the legs with stall kicking. I believe the return of the horse to its more natural environment such as extended pasture time may abolish these behaviors. The ability of the horse to carry out more appetitive behaviors in the ways of food choices may alleviate the need to carry out the latter behaviors that cause possible health issues. Social interaction may play a role as comfort and allelomimetic behavior may cause more focus on eating rather than unproductive behaviors. These suggestions may not be possible as they are dependent on the actions of the owner which may include a restriction to resources in some settings.
- Dodman, N., Schuster, L., Patronek, G., & Kinney, L. (2004). Pharmacologic Treatment of Equine Self-Mutilation Syndrome. Retrieved from http://www.jarvm.com/articles/Vol2Iss2/DODMANJARVMVol2No2.pdf
- Dowler, L., & Siciliano, P. (2009). Prediction of Hourly Pasture Dry Matter Intake in Horses. Journal of Equine Veterinary Science,29(5), 354-355. doi:10.1016/j.jevs.2009.04.061
- Houpt, K. A. (1981). Equine Behavior Problems in Relation to Humane Management. Int. J Stud Anim Prob,6(2), 329-337.
- Houpt, K. A., & Keiper, R. (1982). The Position of the Stallion in the Equine Dominance Hierarchy of Feral and Domestic Ponies. Journal of Animal Science,54(5), 945-950. doi:10.2527/jas1982.545945x
- Houpt, K. A., & McDonnell, S. M. (1993). Equine stereotypies. The Compendium on continuing education for the practicing veterinarian (USA).