Match Stocker Numbers with Resources & Management Style

Producers need to ask themselves a number of questions before deciding on how many stockers to put to pasture. Their carrying capacity will be dependent on their grazing management, available time and labour, combined with goals for market weight and date. Marketing goals can be important in helping a producer decide to utilize pasture resources for quality (higher gain per animal) or quantity (higher gain per acre).

When pastures are continuously grazed, individual animal gain is highest because the animal is able to select high quality forage until late in the season. As grazing pressure is increased, with increased stocking rate and more management-intensive grazing (MIG), selectivity of grazing goes down. With this system, there is a higher forage yield and consequently more pounds of beef per acre produced even though individual animal gains are not as high.

Andy Macdonald, a custom stocker grazier, and 1998 Ontario Pasture Competition award winner, states that average daily gain decreases as management becomes more intensive. If producers want cattle to gain well individually, rotate faster. Jim Johnston, Forage Researcher at New Liskeard Research Station, states that rotational grazing will give at least 20 to 40% more pounds per acre with 8 paddock rotation vs "set stocking". There is no expected increase in gain per head.

Producers need to determine number of acres of pasture available and type of grazing system to be able to calculate their potential carrying capacity.

Assumptions:

• One (1.00) animal unit is equivalent to 1000 pounds of live weight. May adjust up or down by adding or subtracting .10 animal units for every 100 pounds over or under 1,000 lbs live weight. For example, a 700 lb stocker = .7 animal units
• Dry Matter Intake (DMI) - According to University of Wisconsin - Extension publication "Pasture for Profit, livestock need to have daily access to approximately 4% of their live weight in forage (2.5% intake, 0.5% trampling and 1% buffer).
• Estimated Hay Yield: 3.5 tonnes/acre/year. Forage availability for continuous stocking is 4620 lbs/acre/year and for rotational stocking (MIG) is 1540 lbs/acre/rotation and with 5 rotations pasture would yield 7700lbs/acre/year. Reference: Darrell Emmick, Grasslands Specialist, Soil Conservation Service, New York State.

Producer Goal: Producer has 50 acres of available pasture. His goal is to purchase 700 lb steers on May 5^th to market on September 9^th at 925 lbs. This is a total of 127 grazing days and would require approximately 1.8 lbs per day gain which is attainable on good quality pasture. Each animal unit (1000lbs) would require 5080 lbs DM (127 days x 40lbs per day) per season. Keep in mind that the forage demand increases over the grazing period as the livestock gain weight. To plan a system, use an average weight that would be expected midway through the grazing season, i.e. 800 lbs.

Carrying Capacity (# animal units) = # acres ________ X # lbs DM/acre/year _______ divided by 5080 lbs DM required per animal unit.

Continuous Stocking = 4620 lbs/acre/year X 50 acres divided by 5080 = 45 animal units or 56 - 800 lb steers (.8 animal units).

Rotational Stocking = 7700/acre/year X 50 acres divided by 5080 = 75 animal units or 93 - 800 lb steers (.8 animal units).

These calculations should be used only as guides to help you get started. Actual numbers will vary from site to site and year to year because of variations in the weather, soil type, type of cattle, and pasture condition. Keep in mind that shrink will play an important role in your bottom line. Producers have experienced up to 40-50lbs weight loss between the farm gate and the sales barn.

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