Breeding Fuel-Efficient, Profitable Cattle: A Data-Led Approach to Improvement

John Elliot, Rawburn Aberdeen Angus, Kelso

Feed efficiency sits at the centre of the Rawburn breeding programme because feed accounts for around 75% of total production costs in beef systems. Improving how efficiently animals convert feed into gain provides an immediate economic benefit and a clear reduction in environmental impact.

Early ambitions to measure intake directly were limited by the high cost of available technology. In 2016, the GrowSafe system required an investment of £200,000-£250,000, prompting a move toward importing proven feed-efficient genetics from North America. Through this work, Nichols Expectation emerged as a standout sire, combining high efficiency, strong growth and desirable phenotype. Within six years, eight of the ten highest combined-index Angus cattle ever recorded in the UK traced back to this bull.

By 2020, technology costs had fallen enough to justify installing a feed-efficiency unit with eight individual feed bunks, capturing every mouthful eaten by up to 70 bulls per trial. Animals weigh themselves at water troughs, and the system streams 24-hour data for the full test period of 60 days. The first trial revealed the scale of genetic variation. Among 67 bulls, the most efficient converted 3.06kg DM/kg gain, while the least efficient required 5.68kg. This translated into a £192 difference in post-weaning feed cost between two bulls of identical weight and growth. At a 50% transmission rate, this becomes £96 per calf, or £9,600 per 100 calves.

Repeated trials confirmed that feed efficiency is highly heritable (0.45) and strongly predictable from pedigree, with the same sires producing the most efficient offspring. Phenotype, however, showed no useful correlation; blind assessments proved that visual selection cannot identify efficient animals.

Trials also demonstrated age-related decline in efficiency. Bulls re-tested four months later maintained their ranking but required 1.12kg more dry matter per kg gain, highlighting the value of earlier finishing.

Commercial validation came through work with Foyle Food Group, where progeny from Rawburn-sired bulls reached identical carcass weights 40 days sooner, reducing feed use and methane output. A five-year partnership with MacKas Angus in Australia now underpins a carbon-neutral beef programme using over 100 embryos annually from the highest-efficiency Rawburn cows.

Within a generation, herd averages have improved from 4.38kg to 4.14kg DM/kg gain, demonstrating the rapid progress possible when efficiency is measured and selected consistently.

Take-Home Messages

• Feed efficiency is the strongest combined driver of profitability and environmental impact.
• Large, economically significant genetic variation exists and cannot be identified visually.
• Efficiency is highly heritable and predictable from pedigree, enabling rapid improvement.
• Earlier finishing supports higher lifetime efficiency and lower emissions.
• Industry feedback confirms that efficiency-led breeding delivers measurable commercial and environmental gains.