Work

Comparing energy intake estimates derived from using respiratory gas flux measurements with backward dietary energy partitioning for beef cattle

Year: 2025

Type: article

Abstract: The objectives of this experiment were to refine the use of open-circuit gas-quantification methodology to estimate energy intake by ruminants and compare 4 different approaches to account for urinary N (UN) excretion. Eight cross-bred beef steers with a beginning body weight (BW) of 244 ± 15.1 kg were used in a 77-day feeding experiment. Steers were assigned to 1 of 3 multiples of the calculated metabolizable energy (ME) requirement at maintenance (10.7 megacalories of ME), which are 1.1 x maintenance, 1.4 x maintenance and 1.8 x maintenance. Diets were long-stemmed wheat ( Triticum aestivum L.) hay and supplemental alfalfa ( Medicago sativa ) pellets. Respiratory gas fluxes were measured using an automated head chamber system (AHCS; GreenFeed, C-Lock, Inc., Rapid City, SD, USA). Urinary N excretion was accounted for with 1 of 4 approaches and included estimating UN excretion using prediction models based on either 1) diet quality and dry matter intake , 2) BW, 3) assuming a constant value centered on the average of the 2 model estimates (60 g/day), and 4) assuming UN excretion to be 0. Pearson correlations between estimated gross energy (GE) (r = 0.95), digestible energy (DE) (r = 0.88), and ME intake rates and measured values were highly positive (r = 0.85) regardless of the approach used to estimate UN excretion. Approaches to estimate UN excretion differed by 0.81 % at the most when calculating ME intake and concordance of correlations coefficients showed good or better agreement between the estimated and measured GE, DE, and ME intakes (r c ≥ 0.45). This experiment confirmed that short-term breath measurements from an AHCS, together with BW change , can be used to estimate GE, DE, and ME intake by cattle.

Source: Journal of Agriculture and Food Research

DOI: 10.1016/j.jafr.2025.101912

Authors: Stacey A. Gunter, Corey A. Moffet, Colleen Bell, Pablo Gregorini

Institutions: Agricultural Research Service, Lincoln University

Language: English

Topic: Ruminant Nutrition and Digestive Physiology

Subfield: Agronomy and Crop Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Zero hunger

Open Access status: gold

Estimated APC paid: $2,530