Using 3D Imaging to Optimise the Diet of Growing Cattle

Fast and safe three-dimensional (3D) imaging technology gives good in vivo estimates of body and carcass chemical composition in growing beef cattle.

Knowing the chemical composition of livestock is key for accurately estimating their dietary requirements and determining the ideal time for slaughter. Adapting their diet accordingly may improve their feed efficiency, thus helping to enhance the farm’s profitability.

The reference method used to quantify the chemical composition of a cow requires its slaughter so that tissues can be sampled for laboratory analysis. This is a costly and time-consuming method that wastes edible carcass and offal and can only be employed at a single time point along the animal’s life span. Accordingly, it is restricted to scientific research purposes.

Visual or palpation assessment, resulting in classification or scoring (e.g. CH-TAX scoring that evaluates carcass conformation and fat cover), are other available methods. It is also feasible to use imaging technologies such as ultrasound or X-ray imaging. The latter are not yet extensively used, however, due to their limitations (accuracy, costs, safety measures).

3D imaging: a fast, non-invasive and safe method

In this context, the rapid development of 3D imaging technology opens up new prospects. This non-invasive method is safe and easy to use, since it does not require direct contact with the animals. 3D imaging has already been used successfully on dairy cattle to measure specific morphological traits; however, its use to estimate in vivo body and carcass composition has not yet been tested on growing beef cattle.

The aim of this study was to calibrate and assess the precision of 3D imaging for determining in vivo the body and carcass chemical composition of crossbred growing bulls (Brown Swiss dams crossed with Angus, Limousin or Simmental sires).

The 3D images of 100 bulls were recorded at Agroscope Posieux in 2020-2021, either over the course of their growth (from 75 to 520 kg live weight and from 34 to 306 kg carcass weight), or at a fixed weight (517 kg live weight and 289 kg carcass weight) corresponding to the usual weight at which slaughter takes place in Switzerland. Linear, circumference, surface and volume morphological measurements were harvested from 3D images of the animals taken just before slaughter.

These 3D measurements were used as predictive variates in equations estimating the masses and proportions of water, lipids, proteins, minerals and energy in the body and carcass of the cattle which were measured according to the reference method after slaughter.

A promising technology in need of further validation

The 3D imaging method enabled precise estimation of the phenotypes of interest such as live weight, carcass weight and yield, and body and carcass chemical composition.

When the morphological traits measured in vivo by 3D imaging were added to the live weight in the predictive equations, the precision in estimating the body and carcass composition was systematically improved with respect to live weight alone and was comparable to that obtained from the live weight and the CH-TAX classification of the carcass.

This study constitutes a first stage in the development of 3D imaging for the non-invasive in vivo monitoring of body and carcass composition in growing cattle. The results must now be confirmed and validated based on additional studies. Use on-farm or at the abattoir also requires further technical development. If validated and deployed on-farm as part of a precision livestock farming approach, the 3D technology would provide useful data for improving feed efficiency and farm profitability.