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Thinking Of Swath Grazing Your Calves?

Swath grazing mature cows has become a common practice across the Prairies. But researchers at the Western Beef Development Centre (WBDC) wanted to know if swath grazing would work to reduce the cost of backgrounding weaned calves, as well.

WBDC research scientist Bart Lardner expected the calves to do well in a swath grazing system, and they didn’t disappoint. Last winter calves grazing millet or barley swaths did as well or better in terms of health and rate of gain than calves fed ground hay in a pen. Better yet, their cost of gain was 35 per cent less on average, with no adverse effects on performance as they were moved into a finishing program at the University of Saskatchewan’s research feedlot.

Lardner is repeating the trial this winter and hopes to run it again next winter to solidify the data.

Based on these early findings, he offers the following views on implementing a program to swath graze backgrounders.

First, the feed

A 40-acre field at the WBDC Termuende Research Ranch near Lanigan, Sask. was subdivided into four 10-acre paddocks.

Two paddocks were seeded to Ranger (forage) barley and two to Golden German (foxtail) millet. The crops received 50 pounds of nitrogen per acre at seeding and were sprayed at the four-leaf stage with 2,4-D amine for broadleaf weed control.

When swathed in early September, the barley was in the soft-dough stage and the millet 30 per cent headed. For research purposes, they aimed for similar feed quality in the two crops. In real life Lardner says it would be prudent to swath barley a bit earlier — in the late milk stage — and the general recommendation for millet is to swath at 20 to 30 per cent headed.

The barley yielded 3.6 tons per acre, the millet 4.1. Typical yields in the Lanigan area would be 2.5 to 3.0. Larder attributes the superior yields to good weed control, good moisture and lots of heat right from June through August — ideal conditions for warm-season millet.

Crude protein and total digestible nutrients (TDN) on a dry-matter basis were 12.1 per cent and 52.8 per cent in the hay; 13.5 and 64.6 per cent in the barley swaths; and 15.4 and 58.5 per cent in the millet.

The cost of growing the crops worked out to 35 cents per head per day for barley and 30 cents for millet swaths. To put up the hay cost 33 cents per head per day.

Target your rate of gain

To calculate how much swath to allow per calf per day, you’ll first need to determine your targeted rate of gain. In this trial it was 1.8 pounds per day. At this rate a 500-pound calf requires a ration with 11 per cent crude protein and 62 per cent TDN. The amount of total nutrients supplied by the forage is limited by the amount the calf can eat. A 500-pound calf consumes about 3.5 per cent of body weight on a high-forage diet or about 15 pounds per day of dry matter. All the calves in the trial received the same level of supplement in the form of range pellets and trace minerals to balance the ration.

If you’re backgrounding calves for grass, a target of 1.5 to 1.8 pounds per day is appropriate because you don’t want them to get too fleshy then lose condition for the first while on pasture. Calves destined for a feedlot could gain two to 2.5 pounds per day.

The calves

Crossbred steers and heifers born at Termuende in the spring of 2007 were weaned then sorted by body weight into one of three backgrounding systems: drylot (DL), swathed barley (B) and swathed millet (M). The average start-of-test weight of the calves in each group was 513 pounds in mid October.

DL calves were bunk-fed a daily ration of ground hay and supplement, with continuous access to the watering bowl, and bedding.

Both swath-grazing groups were given access to three days worth of feed at a time, about 15 pounds per

day based on the weight of the swaths in the fall. Lardner suspects a week’s supply would be more practical and reduce labour cost on a typical farm working with large groups of calves.

He was pleasantly surprised to see how quickly the calves caught onto snow grazing, particularly with no permanent winter water supply in the field. Water was delivered to troughs every day to start, and every second day after the snow came.

Portable windbreaks with bedding provided shelter, which kept the calves from bedding down in the swaths.

Lardner highly recommends taking 10 to 14 days to wean and settle the calves before starting them on the swaths. Putting in a trainer cow to lead the way to the feed also helps.

Backgrounding performance

Weights were taken four times. Swath-grazed calves lagged behind the DL calves for much of the backgrounding period. The widest discrepancies were noted at the 43-day weight with DL calves weighing 637 pounds, B calves 594 s and M calves 566.

But by the end of February, at day 98, calves on swathed barley averaged 705 pounds, 29 more than drylot calves and 66 more than calves on millet. That’s an ADG of 1.9 on the barley, 1.6 in the drylot and 1.3 on millet.

The performance of the barley calves was somewhat unexpected but Lardner notes barley swaths did test higher in energy than the millet and hay and the calves on barley tended to select the heads over the straw. That wasn’t an option for the calves on millet, so they consumed the entire plant. Millet swaths also had a higher moisture content so pound-for-pound barley swath were more concentrated.

Feedlot performance

Just the opposite happened when these calves hit the feedlot. Compensatory gain gave the millet calves nine per cent better ADG and seven per cent better feed-to-gain (F:G) conversion than the barley calves.

At the end-of-test DL calves averaged 1,388 pounds with a F:G of 7.1:1, barley calves, 1,373 at 7.3:1 and millet calves, 1,338 and 6.7:1.

Bottom line

Total backgrounding costs were $1.86 per head per day ($1.17/lb. of gain) in the drylot, $1.20 (63) for calves on barley swaths and $1.15 (87) for calves grazing millet.

The big differences in cost were for corral cleaning and yardage on the drylot calves, although Larder admits research costs in these areas tend to me higher than real-farm costs. Costs of gain on-farm, for example, would probably been closer to 85 for the drylot, 50 for barley calves and 63 for millet calves.

“The preliminary findings show that calves backgrounded for a slower rate of gain have the advantage of compensatory gain when they hit the feedlot,” Lardner explains. If you retain ownership of your calves at the feedlot, you’ll capture the cost advantage of that compensatory gain, that is, the calves have the potential to gain more on less feed and finish in fewer days on feed. Even if you sell your calves outright to the feedlot, you will have had the advantage of the lower cost of gain during the backgrounding period swath grazing than if you had pen fed the calves.

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