Voluntary limb-load distribution in horses with acute and chronic laminitis

Objectives-To compare limb-load distribution between horses with and withou t acute or chronic laminitis. Animals-10 horses with carbohydrate-Induced acute laminitis, 20 horses with naturally occurring chronic laminitis, and 20 horses without foot abnormal ities (controls). Procedures-Limb-load distribution was determined, using a custom-designed s ystem that allowed simultaneous quantification of the mean percentage of bo dy weight voluntarily placed on each limb (ie, mean limb load) and the SD o f the mean load over a 5-minute period (ie, load distribution profile [LDP] ). Load distribution profile was used as an Index of frequency of load redi stribution, Results-Mean loads on fore- and hind limbs In control horses were 58 and 42 %, respectively, and loads were equally and normally distributed between le ft and right limbs, In addition, forelimb LDP was greater, compared with hi nd limbs, and was affected by head and neck movement. In comparison, limb-l oad distribution in horses with chronic laminitis was characterized by an I ncrease in the preferential loading of a forelimb, a decrease in total fore limb load, and an increase in LDP that was correlated with severity of lame ness. In horses with carbohydrate-Induced acute laminitis, mean limb loads after onset of lameness were not different from those prior to lameness; ho wever, LDP was significantly decreased after onset of lameness. Conclusion and Clinical Relevance-Quantification of limb-load distribution may be an applicable screening method for detecting acute laminitis, gradin g severity of lameness, and monitoring rehabilitation of horses with chroni c laminitis.