The 2024 Oklahoma State University (OSU) Department of Animal and Food Sciences Research Summaries are currently in press. The publication will provide summaries of the cutting-edge research being produced in the department. Look forward to highlights of different research in this column in the upcoming months.
The publication will feature research by Emma Briggs, a Ph.D. student working with Dr. David Lalman at the OSU Range Cow Research Center- North Range Unit, “Using Gas-Flux Data to Estimate Dry Matter Intake for Cattle on a Grass-Hay Diet.”
New open-circuit gas flux technology has allowed measurement of enteric gas emissions for cattle in a pasture-based setting. If a significant relationship exists between feed intake and gas emissions, this system could be used to rank grazing cattle for forage intake and forage utilization efficiency much easier than previous methods.
Therefore, the objective of this research was to evaluate the relationship between gas emissions and forage intake using 100 Angus and Angus-Hereford crossed heifers over a three-year period.
Feeders designed to measure individual animal hay intake were stocked at a rate of 3.6 heifers per feeder to ensure heifers had ad libitum access to hay. Heifers were also used for collection of gas flux data using an open-circuit, portable, gas-quantification system to measure oxygen consumption, carbon dioxide production and methane production. Heat production was calculated using carbon dioxide and methane output along with oxygen intake.
Phenotypic correlations of hay dry matter intake with carbon dioxide, methane, oxygen and calculated heat production were 0.72, 0.49, 0.64 and 0.72, respectively. Average daily gain combined with the estimate of daily carbon dioxide production accounted for 58% of the variation in dry matter intake.
Thus far, results suggest that forage intake can be predicted using the GreenFeed gas quantification system along with average daily gain. The similarity of equations developed using average daily gain plus carbon dioxide or average daily gain plus heat production (which requires measurement of carbon dioxide, methane, and oxygen) suggests flexibility in gas quantification methods used.
In conclusion, these results suggest that there is an opportunity for using heifer average daily gain along with either calculated heat production or carbon dioxide as a method to rank individual animals for dry matter intake in a forage-based system. — Paul Beck, OSU Department of Animal and Food Sciences
