A novel way to increase forage intake by cattle – and possibly increase gain – could be as simple as providing them with their preferred forage varieties, say University of Guelph researchers.

Prof. Ann Clark and graduate student Sara Zippin, Department of Plant Agriculture, are studying if animals show a preference for specific common orchard grass varieties, when given a choice.

"If they like certain grass varieties they might eat more of them," says Clark. "And if they eat more they will probably gain more, which is great for producers."

Four orchard grass varieties were evaluated for palatability (ingestion) by grazing animals at the Elora Research Station during late spring and summer of 2000. The varieties – AC Splendor, Kay, Jay, and Okay – were planted in adjoining replicated plots to allow grazing animals to have equal access to all of the varieties.

The researchers matched the varieties for maturity. They found that all four varieties grew to the same height and yield, and had similar soluble carbohydrate and fibre levels.

Three grazing cycles were evaluated, using bred heifers to graze down the plots for a period of 24 hours. Measurements taken before and after grazing were compared to determine how much of each variety was consumed.

Results show that bred heifers tended to eat more of the AC Splendor variety, but it’s unclear if the increase consumption was due to preference or to canopy architecture. AC Splendor positioned more forage higher up in the canopy, where it’s more accessible for consumption.

Each of the four grass varieties also had plots fertilized with 50, 100, and 150 kilograms of nitrogen per hectare. The nitrogen promoted plant growth, but also appeared to have a positive impact on preference, apart from its effect on yield. Nitrogen may have affected crude protein content, herbage array within the canopy, or another unmeasured feature.

Clark aims to repeat the study in 2002, to determine if the results are replicable over years, and to clarify what may be causing consumption differences.

This research was supported by the Ontario Cattlemen’s Association and OMAFRA.