A preliminary study of grazing intakes of ponies with and without a history of laminitis

Abstract

One possible factor involved in the aetiology of laminitis is grazing intake. Whilst some studies have looked at grazing intake in healthy animals, there has been little comparison made between animals with and without a history of laminitis. The aim of this study was to compare grazing intake between health animals and those with a known history of laminitis. Sixteen mature grass-kept (maintained at grass 24h a day) native breed ponies from World Horse Welfare in Norfolk were used in the study, which was conducted in the month of July for a period of 12 days. All animals were grazed under identical conditions. Grazing areas were of that suitable for the management of animals predisposed to laminitis (for ethical reasons) and therefore herbage mass was low (Yield: 124kg dry matter/ha; sward height of 1–2cm). Faecal samples were collected from 8 clinically normal horses (NOR) and from 8 that were predisposed to laminitis (LAM) in July 2005. Grazing intake was measured using the alkane technique. Dry matter intakes (DMI) per kilogram bodyweight were low in both groups of animals: 1.32±0.31 percent versus 1.62±0.74 percent for NOR and LAM, respectively. There was no difference in DMI between the two groups of ponies (4.43 versus 4.25kg/day for NOR and LAM, respectively). Mean DMI per kilogram bodyweight per day were 1.32 and 1.62 for NOR and LAM, respectively (20 percent difference).There was a greater variability of DMI within the LAM group with intakes ranging from 0.81 to 2.36 percent bodyweight. The low DMI values were attributed to the overgrazed nature of the pasture used in this study, which was unavoidable due to the welfare issues associated with grazing overweight, laminitis-prone horses on good grazing pasture. Further work is required with a larger study population grazing pastures with greater herbage mass.