Blood test identifies feed-efficient cattle

Researchers from Inrae and Eliance have found that a blood test can predict which young cattle are most and least efficient at using their feed. By measuring two to three parameters from a blood sample, they can classify animals accurately before they begin their feeding period.

Focus on practical and affordable criteria

The researchers aim to find criteria that are both easy and inexpensive to measure in real-world farming conditions. They have identified inheritable plasma biomarkers that could be used to select the most efficient animals and tailor their diets accordingly.

Trials on Charolais cattle

The findings were tested on nearly 630 young Charolais cattle across four experimental farms. Researchers evaluated about ten blood biomarkers to determine their relevance in predicting feed efficiency.

Feed efficiency measured by residual feed intake

Feed efficiency is assessed using the residual feed intake index, which compares an animal's actual food consumption to the amount predicted based on its weight and growth performance. This is tested on two different diets: one based on maize silage (starch) and the other on grass (cellulose).

Practical application in fattening cattle

Between 2023 and 2025, the method was tested on 120 young Charolais cattle at the Etablières experimental farm. Animals were classified into two groups based on their blood biomarkers—most efficient and least efficient—and given different diets. This approach resulted in an average 7% reduction in feed usage compared to a uniform diet.

Results on cost and emissions pending

The economic benefits and impact on greenhouse gas emissions from this approach are expected to be published soon, offering further insight into the potential of precision nutrition in cattle farming.