Comparing the performance of finishing hill lambs indoors on three organic forage-based diets, Teagasc Research Officer, Dr. Frank Campion shares some early results from the GROFarmS hill lamb finishing study.

Scottish Blackface male lambs were assigned to one of three treatments over the winter of 2024, all with the aim of evaluating the impact of different finishing diets on lamb performance, environmental outcomes and economic viability.

At a starting weight of ~29kg, these lambs were assigned to one of three feed treatments: grass silage + 500g/head/day of concentrate, red clover silage + 500g/head/day of concentrate, or wholecrop silage (barley, oats, peas) + 500g/head/day of concentrate. All silage was fed in bale form, and the concentrate was composed of organic barley, oats and peas.

For the hill lamb finishing study, lambs were managed under fully organic conditions, with straw lie-back housing. Throughout the feeding period, lambs were weighed fortnightly and drafted for slaughter at 44kg liveweight with appropriate fat cover.

“Initial findings from the first year of the study suggest that overall performance across all treatments was lower than we would have envisaged. Weight gains of 119g/day for the grass silage treatment, 95g/day on the red clover silage treatment and 45g/day on the wholecrop silage treatment were recorded,” Dr. Campion added.

“Despite its higher cereal content, selective browsing proved a challenge when feeding the wholecrop silage and its inclusion as a diet did not lead to increases in average daily gain.

“Additionally, due to the wet summer experienced in 2024, we did note some palatability issues with our red clover silage, highlighting the importance of achieving adequate preservation at ensiling,” Dr. Campion added.

Although still early days in the experiment, with repeated trials planned for this coming winter, Dr. Campion noted that initial findings (available in table 1 below) point to the need to starting liveweights to be higher for hill lamb finishing and feed intake is emerging as a key driver of performance.

Table 1: Initial findings from the organic hill lamb finishing study

“Further data collection and repeated studies will aim to identify optimal diet formulations and management practices that support organic hill lamb performance,” Dr. Campion concluded.

Find out more about Growing Resilient Organic Farming Systems (GROFarmS) here.