Pasture intakes by horses and ponies: control and management

Take home messages

Equines with free access to ample pasture have been reported to ingest between 1.3->5% of BW as DM/d although most estimates report intakes of 1.8-3.5% of BW/d. Dry matter intakes (DMI) of 2% of BW/d are generally considered sufficient for most equines to maintain an appropriate body condition, so for many animals with high pasture intakes there is a danger of their becoming obese. Therefore, some means controlling pasture intakes of such animals is necessary.

Methods of restricting pasture intakes explored:

Sward height: only very short swards (1-2cm) likely to be effective in reducing daily pasture DMI, probably due to physical limitations imposed on intake rates. Higher sward heights unlikely to be effective in reducing pasture intakes.

Strip grazing: Gradual access to fresh pasture by strip grazing, either with a lead fence only (so grazing area gets larger as time progresses) or with a lead and back fence (so grazing area stays the same with previously grazed areas recovering) were equally and highly effective in reducing weight gain in ponies compared with ponies that had free access to the same initial total herbage mass as the strip grazed ponies.

Time at pasture. Restricting time at pasture was only partially effective in reducing pasture DMI. Animals with restricted pasture time showed compensatory ingestive behaviour, accelerating their intakes such that they consumed disproportionately large amounts of pasture. Thus, DMI of animals with 3, 6, and 9 hours pasture access respectively consumed 43, 69 and 74 percent of the DMI of ponies with 24 h pasture access. Other animals with 3 hours pasture access increased their pasture intakes to 41 percent of their total daily DMI. Such information should be factored into regimens using restricted grazing times as a means of controlling intakes to allow appropriate forage provision when not at pasture.

Grazing muzzles. Consistently reduce pasture intakes, ranging from 30-80% reductions in DMI compared with when grazing unmuzzled. Reductions in intakes were apparently unaffected by season or grass species. Some ponies that were muzzled for 10h/day and allowed free pasture access for 14 h, maintained their current weight, whereas others gained as much weight as unmuzzled ponies grazing for 24 h. Thus, grazing muzzles may be most effective when used in conjunction with stabling when unmuzzled rather than with periods of being muzzled and unmuzzled at pasture.

References

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