Author
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AIKEN, GLEN |
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Submitted to: Cow Country News
Publication Type: Popular Publication Publication Acceptance Date: 1/10/2017 Publication Date: 2/1/2017 Citation: Aiken, G.E. 2017. From the Lab Bench: Do you manage pastures for maximum gain per animal or gain per acre?. Cow Country News. Pg. 52. Interpretive Summary: An important decision for cattle producers is to manage their pastures to either maximize output (weight gain, weaning weights, etc.) per animal or output per acre. Output per animal is maximum over a range of light stocking rates that results in pasture growth to be greater than pasture intake by the animals. Unfortunately, these stocking rates for most forages are too light to be economical and too much forage is wasted. Heavier stocking rates will cause a decrease in output per animal, but increase in output per acre; however, excessive stocking rates are not sustainable and both output per animal and acre will be low. The sustainable stocking rate falls within a range of rates where pasture growth and forage intake are in balance. When directly selling calves from the farm, the challenge may be to stock pastures in the upper range of optimum stocking rates. The other option to retain ownership of the calves into the feedlot could necessitate that body weights be maximized by using a stocking rate that is in lower range of optimum stocking rates. This information is of interest to cattlemen that want to use sustainable stocking rates that can meet production goals targeted to maximize either output per animal or per acre. Technical Abstract: An article was written to discuss managing cattle pastures to maximize either weight gain or milk output per acre or per animal. There is no or little change in output per animal over a certain range of light stocking rates that allows pasture growth to be greater than forage intake, and increasing the stocking over this range will directly increase output per acre. However, there is a critical stocking rate beyond which forage intake is greater than forage growth and average daily gain (ADG) will decrease and the increase in total gain per acre is more gradual. Over this range of moderate stocking rates, cattle are forced to graze less palatable and nutritious plant material (less leaf and more stem). Further increases in stocking rate will lead to less forage available for cattle to consume and ADG and total gain per acre will both plunge. The optimum stocking rate for a given pasture is not one that provides the greatest gain per acre and not necessarily the one that provides the maximum ADG (dotted vertical line in figure). It actually is a compromise between the maximum ADG and gain per acre, with it being centered in a narrow range of rates that are both economically optimum and sustainable. If cattle are sold directly off the farm, the goal may be to maximize output per acre by maintaining stocking rates in center or slightly higher in the range of optimum stocking rates. If ownership of the cattle are being retained in the feedlot, then the production goal could be to maximize output per animal by maintaining stocking rates on the lower end of the range of optimum stocking rates. |
