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Project Shows Overgrazing Causes Damage

A forage project undertaken by the South East Research Farm (SERF) in Redvers, Saskatchewan is demonstrating that heavily grazed pastures can lead to permanent damage.

The 2010 Fairlight Grazing Project showed the negative effects of overgrazing by dividing a section of southeast Saskatchewan land into six paddocks. Two paddocks were planted with a sainfoin- alfalfa-meadow brome grass mixture, two were planted with a cicer milk vetch-alfalfa-meadow brome mixture and two were planted with native grass and alfalfa seed.

One paddock of each mixture was overgrazed (season-long grazing where plants did not exceed six inches in height), while the other was moderately grazed (two passes of grazing with the second not occurring until regrowth reached 12 to 18 inches in height).

The findings clearly demonstrated that in the overutilized pastures, broadleaf weeds began to emerge. If this trend continued, which often is the case, cattle would have access to far less nutrients over time.

Even though there was some tall growth left, the remainder of the grass had been severely overgrazed by being bitten or utilized several times in the growing season without the plant being able to put reserves in its roots system, said Darcy Boon, lead technician for the South East Research Farm. If continuous overgrazing is experienced, Boon said pastures could have to be rested to allow desirable species to re-establish themselves.

With the wet year experienced in 2010, the moderately grazed paddocks produced heavy growth which led to lodging once fall arrived. The rapid growth of grass in the moderately grazed paddocks and the inability of the cattle to keep up with the oversupply of food led to valuable conclusions about stockpiled forage. It was found that stockpiled forage does present a viable food source for cattle and a good alternative to haying when wet conditions prevent it.

When the cattle returned to their normal wintering pasture location, they preferred to graze on the available lodged forage versus eating from a round bale of hay. The project cattle also were able to forage through a layer of snow, however, it was determined that this was learned behaviour exhibited by mature cattle.

In my opinion, the forage should have been lightly grazed early on, so that it did not lodge, but stayed in an upright position, said Boon, adding that farmers may have encountered some of the same issues this year, considering the wet conditions.

My advice if you can t get in to hay in a wet year, is to lightly graze the pasture in early fall and then let it stand until the cows move in later in the year, which can be after a snowfall.

The second part of the research project involved the study of water supply in the various paddocks. Solar pumps were used to draw dugout water into drinking troughs.

Research shows that cattle gain weight better on clean water pumped into troughs, said Boon, adding that the solar water system used by SERF was a summer-only unit. With the system costing about $8,000, it s a good investment for cattle producers as fouled dugout water can lead to increased algae growth.

SERF research manager Lana Shaw said the study is valuable for cattle producers as very few research farms have grazing projects.

The hope is that it will increase the knowledge of sustainable grazing practices.

ChristaleeFroesewritesfromMontmartre, Saskatchewan

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Christalee Froese writes from Montmartre, Sask.



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