Study explores most effective grazing method

LINDELL BEACH, B.C. – Grazing cattle like lots of leaves growing in easy reach of their tongues, which they use to wrap around the leaves and pull them off the stem.

This means less roaming, more nutritious intake and less expense of energy.

Agricultural scientists call it the herbage intake rate, a key factor in determining weight gain for pasture raised cattle.

The practical side of this for ranchers is that by knowing the height and leafiness of plants, they can determine how long to leave cattle in a pasture before moving them.

Read Also

Hogs’ transport stress called costly

Poor trailer design and transportation stress are killing pigs and costing the pork industry millions of dollars in penalties, meat quality downgrades and failed welfare audits, according to research by a federal scientist.

“Herbage intake depends not only on herbage nutritive value but also on its availability and accessibility, with the latter being directly related to sward canopy structure,” said Stacey Gunter, research leader with the U.S. Department of Agriculture’s Southern Plains Range Research Station in Woodward, Oklahoma.

Gunter, who published his research in theJournal of Animal Science,said cattle like the taste and nutrition of large leaves and prefer them to grow high on the stem so they can use their tongues to pull them off.

Being able to take larger, more frequent bites allows them to achieve their daily nutrient rations with less caloric output.

Gunter said most advances in understanding the relationship between cattle and plants are often based on artificially modified or constructed pastures.

In an experiment to study steers’ short-term grazing and foraging activities, Gunter’s team used wheat pastures blocked off into three 18 by 1.7 metre corridors that had been planted using three tillage methods: conventional tillage (CT), minimum tillage (MT) and no tillage (NT).

Plastic posts were set every two metres so observers could watch and record the cattle’s grazing patterns. The grazing corridors were assessed on plant height, mass, tiller and bulk density one day before the beginning of the grazing sessions.

The researchers studied three Angus steers by turning each loose in a corridor and allowing them to graze freely until it had moved the length of the corridor.

Each steer had its own video operator and two trained observers who counted bites and steps during the grazing session.

The steers were fasted the night before and fed two kilograms of ground corn three hours before the beginning of the experiment to reduce their differences in appetite.

The steers were adapted to the support team and trained to graze the corridors one month before the experiment began.

“Each steer goes down one corridor once,” Gunter said.

“Each corridor is only used one time. The steers could not go up and down the corridors but grazed along it.”

He said ruminants generally remove only the uppermost parts of plants, which could be a mechanism imposed by the physical structure of plant tissue to overcome resistance to defoliation.

The three corridors had similar leaf-to-stem ratios but different sward surface heights, which likely influenced leaf accessibility.

The no tillage corridor had the tallest sward surface height.

“We found that the steer spent more time in the NT because there was more food and it needed to spend less time walking (between bites). In the CT and MT they grazed faster because they were taking more bites more rapidly and more time walking.”

Gunter said previous tillage trials had found that no tillage produced the best results for pasture because the grasses grew more upright with a taller canopy, which was the preferred presentation for cattle.

Because the no tillage corridor had the greatest surface height and leaf accessibility, the steer could more easily penetrate the growth with its muzzle and use its tongue to wrap around the leaves and pull them free.

“Pastures with greater leaf accessibility and similar herbage quality may lead grazing cattle to reach the same herbage intake amount in less time while possibly grazing more efficiently per unit area,” Gunter and his colleagues wrote in their report.

“Consequently, when cattle are grazed by using intermittent defoliation methods, it would be logical to think of reducing the area and time allocation in pastures where taller swards with leafy upper canopy strata are found.”

———

The new Case IH Precision Hoe 800 air hoe drill is ideal for small-seeded crops on large acreages. The unique parallel link row-unit provides superior depth control in uneven field conditions. The single shank design precisely delivers both seed and fertilizer at the proper depth, ensuring every seed reaches its potential. Wide working widths cover more acres in less time, yet the narrow transport width lets it travel safely from field to field. And, it’s ideally matched with the industry-leading Case IH Precision Air aircarts. See us today for all the details.

CASEIH.FORTHOSEWHODEMANDMORE™

Hi-Way Service Ltd.

Balzac, Lethbridge, Medicine Hat, Taber, Bow Island, Picture Butte, High River, Milk River, Vermilion,

Drumheller, AB ……………………………………………310-CASE

Camrose Farm Equipment

Camrose, AB …………………………………………780-672-9136

Gateway Farm Equipment

Grande Prairie, AB ………………………………….780-532-9161

AgriTrac Equipment Ltd.

Westlock, Barrhead, Vegreville, AB …………..888-349-3720

Hi Line Farm Equipment Ltd.

Wetaskiwin, AB ………………………………………780-352-9244