The Derrypatrick herd is a grass-based, suckler calf-to-beef research herd located at Teagasc Grange in Co Meath. In previous years, late-maturing heifers and steers were finished indoors on a grass silage plus concentrate-based diet at 20 and 24 months of age, respectively. Under this system, the main variable costs were silage production, concentrate supplementation and chemical fertiliser, respectively.

By 2022, rising input prices, particularly fertiliser at approximately €1,000/t, increased fixed costs associated with building sheds, labour constraints, relatively low beef prices (circa €5/kg carcase weight) alongside growing environmental pressures and policy ambition, prompted the establishment of a new research project.

In response to these challenges, we developed a lower-input, grass-clover-based production system, coupled with targeted animal genetics, designed to finish cattle at a younger age from pasture, thereby reducing winter housing and silage costs, while also lowering reliance on chemical fertiliser and concentrate feed.

Using an 80-cow spring-calving herd stocked at 170kg organic nitrogen (N)/ha (2.2 LU/ha), a production system was established to finish steer and heifer progeny off grass at 19 months of age without concentrate supplementation. The study is comparing two pasture systems (grass vs grass-clover) and two sire breed maturity types (Aberdeen Angus vs Charolais) and will run for three production cycles. Progeny remained in the same pasture system from birth-to-finish.

On the grass-clover system, white clover was used on the grazing platform (75kg N/ha or 60 units N/acre) and a red clover grass mix (zero N) was used on the three-cut silage block.

An obvious challenge with this pasture-finishing system was achieving an adequate carcase fat score (=2+), especially for the late-maturing breed, and attaining sufficient carcase weight at 19 months of age. In this regard, specific sires were chosen within breed, with a focus on ‘weight-for-age’ and ‘improved’ fat cover at young ages. The following criteria were used to select the Aberdeen Angus and Charolais sires used on mature cows:

  • Calving difficulty < 8 % (ie easy-calving).
  • Carcase weight: five-star (ie heavy).
  • Carcase fat: 1- and 2-star within or across breed (ie improved ‘fleshing’ ability).
  • Age to slaughter: four- and five-star within or across breed (ie early finishing age).

    • Pasture systems results

    To date, two of the three full production cycles have been completed. Lactating cows grazing grass-white clover swards gained an extra 16kg liveweight and + 0.1 body condition score (scale 1-5) from calving to weaning, compared with those grazing grass swards.

    Their calves also benefited, weighing 14kg heavier at weaning compared to grass-only calves. At a weanling value of €5.50/kg, this represents an extra €77/calf at weaning.

    During the first indoor winter, weanlings on the grass-clover system were offered grass–red clover silage plus 1.5kg of concentrates per day.

    In the course of this indoor period these cattle gained 11kg more liveweight (0.72 vs 0.61 kg/day) than weanlings on the grass system, which were offered grass silage and the same level of concentrate. As a result, by turnout the following spring, the yearling cattle on the grass-clover system were 25kg heavier than the grass system (at 12 months of age).

    However, because the winter liveweight gain of weanlings was greater for the grass-clover system than the grass system (0.72 vs 0.61 kg/day), the slower-growing cattle on the grass system had greater compensatory growth during the second grazing season, achieving higher daily gains (0.94 vs 0.88 kg/day) than the grass-clover cattle.

    Consequently, the liveweight difference decreased from 25kg to 15kg at finishing but was still in favour of the grass-clover system (601 vs 586kg), resulting in a 10kg heavier carcase at the same age – equivalent to an extra carcase value of €75/head at today’s beef price.

    Finishing heifers were supplemented at grass towards the end of the grazing season.

    Sire breed maturity results

    Throughout their lifetime, cattle received an average of 241kg of concentrates/head, with no concentrates fed during the finishing phase at pasture. All cattle were finished on the same day for experimental treatment comparisons.

    Overall, there was no significant difference in carcase weight between the two sire breeds; however, the Charolais-sired cattle had lower fat and higher conformation scores. With the exception of one animal, the Angus-sired cattle were all ‘finished’ (carcase fat score, = 2+). In summary:

  • 100% of Aberdeen Angus heifers were finished (average 301kg carcase; R–, 4–).
  • 98% of Aberdeen Angus steers were finished (average 335kg carcase; R–, 3=).
  • 93% of Charolais heifers were finished (average 312kg carcase; R=, 3–).
  • 78% of Charolais steers were finished (average 336kg carcase; R=, 2+).

    • The early-maturing Aberdeen Angus were well suited to a pasture finishing system at 19 months of age, as were the Charolais heifers. Good forage management and careful within-breed selection for sires with superior weight-for-age and earlier fat cover allowed a high proportion of cattle to be finished off grass with minimal concentrate input.

    While the majority of the Charolais steers were finished, it is obvious that such late-maturing breeds are more suited to production systems that allow them to express their genetic potential to achieve heavier carcases.

    Therefore, finding an optimum system for late-maturing steers will be examined in the next phase of the research (commencing in spring 2026), where Charolais cattle will be offered different concentrate finishing strategies to target heavier carcase weights of 380kg for steers at circa 19 months of age.

    Herbage production

    To date, annual herbage production was similar (12.2t DM/ha) across the two sward types as measured via PastureBase, with the grass-clover system receiving half the level of chemical N fertiliser than the grass-only system (150kg N/ha (120 units/acre) vs 75kg N/ha (60 units N/acre)).

    Incorporating red and white clover into grassland systems requires a high standard of grassland management, particularly in the case of red clover. It is best practice for farmers to become familiar with clover management before introducing these swards. Guidance on managing clover is available on the Teagasc Grass10 website.

    Over the three-year experimental period at Derrypatrick, no fatalities from bloat were recorded. However, appropriate precautions remain essential, especially where clover content is high (greater than 30%), or where cattle are not accustomed to grazing clover-rich swards.

    Managing tips to prevent bloat include, anti-bloating agent in drinking water 24 hours in advance, ensuring consistent access to fibre (silage/hay), using strip wires to prevent gorging and avoiding turning hungry cattle onto lush, wet clover pastures.

    Upcoming events

    More information about this experiment (eg cattle intake, enteric methane emissions, soil nitrate leaching, seasonal milk yields, etc) will be available at the BEEF2026 open day in Grange on Wednesday 1 July.

    A full economic analysis of both pasture systems is currently underway, with results to be presented at the Teagasc Grange Webinar on 25 February. Farmer discussion groups are also welcome to come visit the experiment on request (peter.doyle@teagasc.ie).

    Acknowledgments

    Peter Bennett, Walsh scholar, is responsible for collecting and analysing the production system data. Sarah Armstrong, also a Walsh scholar, is measuring cattle enteric methane emissions as part of the Department of Agriculture, Food and the Marine funded RumenVentory project.

    The support of the farm manager, research technicians and farm staff at Teagasc Grange is gratefully acknowledged.