The importance of precalculating pasture days


Source: Alberta Agriculture and Forestry,

Each pasture season has its challenges whether its periodic drought or cool weather that can slow or halt forage growth, cattle numbers change as beef producers adjust to markets and overhead costs always seem to be on the rise. In facing these challenges, producers strive to find ways to create more profit.

To increase profit, the best way is usually to keep down the cost per pound of animal raised. Pasture is cheaper than feeding mechanically harvested hay or silage systems. High pasture production is needed for all grazing animals and for a cowherd the ability to extend the grazing season is particularly important. Pastures can only meet these goals if they are managed with some planning. A plan for a grazing season starts before cattle are turned out on grass. Decisions are based on the information gathered from a fall assessment of pastures. Just as a winter feed inventory is done in fall to determine if there are enough bales or silage to last the winter, the same should be done with pastures in winter time before spring turnout arrives.

“To start, first look at the big picture,” says Grant Lastiwka, pasture specialist with Alberta Agriculture and Rural Development. “It’s easiest to use percentages and compare them to normal. If your cattle numbers are 10 per cent more, you will need 10 per cent more grass. Also, if pastures were hurt by drought and grasshoppers or hammered with overgrazing, they could be 30 per cent less productive. If this is the case, it means that there is going to be a 40 per cent shortage of grass.

“Planning early is very important because if you determine that you have a shortage of pasture, there is still time to make other decisions such as renting more pasture, seeding annuals, selling cattle, fertilizing or feeding longer so that the grass can get the jump start it needs. Knowing what you’ve got and deciding how best to manage your grass is an important step in meeting pasture needs and helping with next year’s cash flow.”

To start, do an inventory to see if animal numbers and the desired length of the grazing season are in balance with pasture production. Whether it is written down or not, everyone knows roughly when they start and end grazing, so begin by calculating the number of grazing pairs and yearlings. Pasture production can then be calculated as Animal Days (AD) or Animal Unit Months (AUM).

For example, 150 cow/calf pairs grazed from May 25 to October 30, 2003 (150 days) is equivalent to 22,500 AD of grazing. If there are 165 pairs (10 per cent more), an additional 2,500 AD are needed if the goal is to graze until October 30. If all weather factors stay constant and no extra grass is grown and no cows are sold, the grazing season will be done by October 15. Presuming grazing is about half the cost of feeding hay or silage, this means the operation is set up for some extra costs and may face a cash flow problem. From the pasture production side, the pasture in this example produced 22,500 AD of grazing from 600 acres or each acre produced 37 AD. Due to factors such as dry falls and compound effects from previous grazing years, the beef operator may feel that pastures will produce 30 per cent less than normal – in this example that means 15,750 AD or 26 AD/acre. The calculation of 15,750 AD/165 animals works out to a 95-day grazing season. In this example pasture will be done by August 28, far before the October 30 date.

“By knowing the shortfalls, it’s possible to effectively take action before damage is done to pastures, cattle performance and cash flow,” says Lastiwka. “The best economic solution may be to sell a few of the poorer cows or early wean and ship the culls rather than taking the risk of loosing out on grazing days. In addition, if some winterfeed is left, delaying turnout will help to set up a grass buffer. As a general rule, for every day cattle are held off grass, three more days of grazing can be added to the season. Later turnout, on average, means a net return of two days. At pasture costs of $1/day, this means $2 more from your own land in grazing this year for every day held back.”

Another option is renting pasture. Using the same example, the grazing shortfall is calculated as 25,000 AD – 15,750 AD = 9,250 AD (26 AD per acre) = 356 additional acres needed to graze 165 cows until October 30.

“Seeding annuals, fertilizing, arranging for crop aftermath use and early weaning can also be used to offset pasture production shortfalls,” adds Lastiwka. “Being flexible with grass and cash gives producers options to make wise cattle decisions. Fewer animals grazed longer and each making a profit may be more profitable than more animals going onto winter feed earlier and each losing money.”

Ag-Info Centre 310-3276, Alberta Agriculture & Forestry


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