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Mob grazing suits smaller farms

Doing the math on mob grazing and paddock size

For family farms that might be feeling the crush of ever-larger neighbours, Williams’ message to optimize land use was welcome.

“This is our next step forward to keep the family farm going,” Ceri Phillips said.

“It’s nice to see that smaller farmers in Manitoba can actually make a good living off smaller acres instead of being a large grain farmer anymore,” she added.

Phillips plans to take over her family farm near Birtle. Claire Phillips, who attended along with the future farm owner, says their operation plans to shift to high stock density, holistic grazing in the near future and intends to shrink acres.

“The main focus is going to be a 400-acre block of land and that will be it to see what we can do with it and see what we can achieve and I’m very hopeful,” Claire Phillips said.

Doing the math on mob grazing and paddock size

Paddock size is the most common question for producers looking at mob grazing.

The answer, according to grazing workshop instructor Dr. Allen Williams, lies in dividing available forage with per-head feed requirements.

Available dry matter is a function of plant height and density, attendees heard. Plants are measured at sites throughout the field, making sure to include all species in the mix, to find average height. Then, looking from straight above, stand density is estimated. If no bare ground is seen, stand density is considered “excellent,” “good” if five per cent is open ground and “poor” if bare soil makes up 10 per cent of the view.

An “excellent” stand will offer 300 pounds of dry matter per acre for every inch of height, a number that falls 100 pounds for every downgrade in density, Williams said. Using that formula, total field forage per acre can be calculated.

Actual available dry matter will be much lower however, Williams said. Under his system, which gives high priority to soil health and maximum forage production, only 50 per cent of available forage should be grazed before livestock are moved.

Once available feed is calculated, ideal stock density can be found and, from there, paddock size.

An animal should eat three to 3.5 per cent of its body weight a day, Williams said, but added that he aims for 3.5 per cent, a least partially to take aging calves into account as they start to graze. Using that figure, feed per head per day can be found.

Dividing available feed per acre with the needed feed per head will then give the stock density, how many head can ideally graze a single acre per day.

The system is not perfect, he noted, but is easily adjusted if the farmer sees forage is too closely cropped (often because livestock are left in the area too long) or grazed in patches, a mark of low stock density.

About the author


Alexis Stockford

Alexis Stockford is a journalist and photographer with the Manitoba Co-operator. She previously reported with the Morden Times and was news editor of  campus newspaper, The Omega, at Thompson Rivers University in Kamloops, BC. She grew up on a mixed farm near Miami, Man.



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