Complications secondary to hospitalization or prolonged immobilization

Hospitalization or prolonged stall immobilization is an unnatural experience for a horse. Feral horses typically roam in stable, social groups over large grazing territories, spending 16–20 hours per day foraging on mid- to poor-quality roughage. In contrast, the immobilized horse will be living in relatively small stalls, eat a limited—but rich—diet at specific feedings, and typically live in social isolation. Although the horse has been domesticated for more than 6000 years, there has been no selection for an equid who no longer requires an outlet for these natural behaviors. Researchers have utilized equine stereotypies as a welfare indicator, and have proposed the psychological wellbeing of horses kept in a stall to be compromised. A “stressed “horse will have increased cortisol levels which can be a detriment to the horses’ natural immunity. The following complications secondary to hospitalization or prolonged immobilization will be discussed ; Small Airway Inflammation, Gastric Ulceration, Hospital associated infections, Laminitis, Gastrointestinal disorders (Impaction and Antibiotic induced diarrhea), and Physiologic wellbeing.

Respiratory Conditions

Horses with a medical condition that must be prohibited from laying down will sometimes have their heads tied to either a stall wall or a highline will be ask risk for developing lower airway inflammation. In a study looking at the confinement of horses with their heads elevated for periods up to 24 hours evaluated the extent and the effects of bacterial contamination of the equine lower respiratory tract. Significant (P < 0.05) increases in bacterial numbers (up to 109 colony forming units/mL in transtracheal aspirate derived samples) occurred within 6 or 12 hours in most horses. Pasteurella/Actinobacillus spp and Streptococcus spp were most commonly isolated. Lowering of the head for 30 minutes every 6 hours to facilitate postural drainage did not prevent multiplication of organisms to levels equivalent to those achieved by horses where the head was elevated for 24 hours. When horses were released from confinement and heads were no longer maintained in an elevated position, clearance of accumulated secretions and bacteria occurred within 8 to 12 hours. Thus, confinement with the head elevated resulted in significant bacterial contamination and multiplication within the lower respiratory tract during a period often encountered in routine management procedures, such as transportation. The clearance of accumulated secretions occurred over a prolonged period after release from such confinement.

Exposure to airborne dust and other irritants present in the barn environment appears to play a major role on the pathogenesis of airway inflammation. Development of airway inflammation in otherwise healthy horses occurs upon introduction to barn confinement and higher dust environs increase the degree of airway inflammation, as do higher respirable endotoxin concentrations.

Gastrointestinal Conditions:

Long confinement periods are related to gastric ulcer prevalence. Periods in stalls longer than 19 hours per day increased the risk of gastric ulcer onset, although other studies did not show any difference in gastric lesions intensity when comparing full-time with part-time confinement or permanent grazing. Husted et al. (2009) determined no significant changes in the gastric pH of horses divided into three groups ; grass paddock, stall alone or stall with adjacent companion. This suggests the involvement of other factors in the pathophysiology of gastric ulcers.

Confined horses experience changes in feeding management in relation to the amount, frequency, and type of food. In addition, confinement, contrary to the gregarious and social nature of equines, induces stressors and behavioral, neuroendocrine and metabolic changes that impact different organic systems. [...]