Submitted to: University of Kentucky Cooperative Extension Bulletin
Publication Type: Government Publication
Publication Acceptance Date: August 25, 2006
Publication Date: N/A
Interpretive Summary: Decision on which stocking rate to graze a horse pasture is critical, particularly if the forage is expected to meet the nutrient needs of the horses. Over- and under-grazing will have major implications on economic stability of a horse operation. Forage growth with light stocking rates will be in excess of consumption and cause an accumulation of mature, lower quality forage, which eventually reduces the ability of horses to graze selectively. Continuous heavy stocking inevitably results in the deterioration of pastures. A good indicator of excessive stocking rates is when manure piles are readily seen, and when horses are observed grazing closer to these piles. Stocking rates should be based on total body weight per acre, and not number of horses per acre. This is because a 1000 lb horse will consume daily approximately 40% more forage dry matter than one that weighs 600 lb. Qualified decisions on setting or adjusting stocking rate for a particular pasture come from knowledge of the growth potential of the forage base, which is based on soil characteristics, fertility, and the prevailing weather patterns. Lack of this knowledge and experience will require the horseman to be conservative in setting a stocking rate. A stocking rate of 600 to 700 lb/acre should be a good starting stocking rate for most pastures. Stocking adjustments can be made gradually according to increases or decreases in visually observed changes in forage supply, and should account for the prevailing rainfall. All horsemen that rely heavily on pastures to meet the nutrient needs of their horse herds can maintain productive pastures by making carefully thought decisions on stocking rates.
Technical Abstract: Decision on which stocking rate to graze a horse pasture is critical, particularly if the forage is expected to meet the nutrient needs of the horses. Challenges and management for targeting the optimum stocking rate, defined as the stocking rate that allows forage consumption to approximately equal pasture growth, was presented and discussed. Under-grazing results in accumulation of mature, lower quality forage leads to spot grazing, which encourages weed encroachment. Conversely, over-grazing will limit forage supply and eventually weaken grass stands, making them vulnerable to weed encroachment. Grazing management systems should be developed to optimally graze horse pastures by reducing over- and under-grazing that can occur seasonally. These managements can entail stocking rate adjustments and some reliance on hay and concentrates. Careful decisions on setting and adjusting stocking rates should improve chances of maintaining productive pastures and economic stability of the horse farm.