Nutritional management of finishing beef cattle

Emily Roskam David Argue Niall Kerins Mark McGee

In 2025, the national average finishing age of prime beef cattle was 26.5 months. To improve environmental sustainability of Irish beef production systems a goal, embodied in the national Climate Action Plan, is to reduce mean age at finish by ~three months by 2030 relative to 2018. This can be achieved by improving animal nutrition, genetics and health. Beef production system blueprints are broadly based around finishing spring-born cattle at the end of the second grazing season (~20 months of age), during the second winter (~23-24 months of age), or extending into the third grazing season (~26-27 months of age). Factors such as animal sex (steer, heifer, bull), origin (suckler-bred, dairy-bred) and genotype (early- vs. late-maturing) will determine the most suitable production blueprint to achieve optimum carcass specifications of 280-380 kg carcass weight, fat score (2+ to 4=) and conformation score (≥O=).  Beef farmers should focus on optimising animal health and nutrition within their chosen beef system rather than moving between different systems as a reaction to short-term changes in market prices.

Finishing cattle at pasture

Animals can be finished directly off pasture either in the second or third grazing season, with or without concentrate supplementation. Regardless of the blueprint employed, the provision of adequate allowances of high-digestibility grass through informed grassland management is essential to maximise system performance. Maintaining a rotational grazing system and targeting a pre-grazing herbage mass of ~1,800 kg dry matter (DM)/hectare (ha) will optimise both herbage production and grass intake. Research from Teagasc Grange has demonstrated that grazing suckler-bred cattle to a post-grazing sward height of 6 cm compared to 4 cm during the second grazing season, resulted in 11 kg extra carcass weight at finish. This additional growth performance was driven by increased animal DM intake, and although this increases herbage requirement it is not really an issue for most beef cattle farms, which have a relatively low stocking rate. Furthermore, research at Grange has shown that the incorporation of white clover in perennial ryegrass swards resulted in superior cattle growth during the second grazing season compared to animals grazing grass-only swards (Further information: Producing beef from grass-forage-based systems).

Early-maturing breed cattle and heifers may achieve adequate carcass finish off pasture-only, whereas late-maturing breeds typically require concentrate supplementation to maximise carcass weight and achieve target carcass fatness, especially at a young age (< 20 months).  In practice, grass digestibility often declines from mid-summer into autumn which is characterised by an increase in fibre content. Additionally, herbage supply is often restricted in autumn due to declining grass growth and inclement grazing conditions.   Carcass growth response to concentrate supplementation at pasture is higher where grass supply is low and where grass digestibility is poorer and usually declines as concentrate supplementation level increases. Studies at Grange have shown that at adequate grass allowances (~20 g DM/kg live weight) in autumn, feeding ~0.50-0.75 kg fresh weight of concentrate per 100 kg live weight resulted in carcass growth responses in steers between 30 and 110 g carcass per kg concentrate. For grazed grass, dietary energy rather than protein is usually the limiting factor. Grass swards can contain between 15 and 30% crude protein on a DM basis depending on nitrogen fertiliser application rates, clover inclusion rate, time of year and rotation length. This crude protein concentration is in excess of protein requirements for finishing heifers and steers (~12% crude protein) with bulls benefiting from slightly higher levels. Consequently, supplementation with concentrate energy sources is required. Three studies at Teagasc Grange showed that cattle performance was similar for starch-based (barley) compared to fibre-based (pulp) concentrates as supplements to autumn grass.

Finishing cattle indoors on grass silage-based diets

Indoor finishing systems in Ireland are typically based on grass silage as the basal forage. Dry matter digestibility (DMD) is the primary factor influencing the nutritive value of forage. The performance of beef cattle increases with increasing grass silage DMD and the greater the proportion of silage in the diet the higher the impact of DMD. Consequently, the production of high-digestibility silage is fundamental to achieving target animal growth rates and carcass specifications. Several factors influence silage ‘quality’ (Further information: Making quality silage on beef farms). Harvest date is the primary factor influencing silage DMD. Research at Teagasc Grange has shown that each week post-heading date, grass silage DMD will decrease by ~3.3 percentage units.

Concentrate supplementation strategies

Quantity and quality of concentrates

Silage DMD determines concentrate supplementation requirements. Each unit decrease in silage DMD, requires an additional ~0.33 kg concentrates per animal daily to achieve target growth rates (Table 1). Therefore, every percentage unit increase in silage DMD has the potential to improve animal performance, while reducing feed costs.

Table 1. Concentrate supplementation necessary for finishing steers (~600 kg) to achieve ~1 kg live weight gain/day and the respective costs during the finishing period for grass silage differing in dry matter digestibility (DMD)

*Concentrate costs based on €350/tonne fresh weight

Increasing the level of concentrates in the diet reduces grass silage intake (substitution rate) but increases live and carcass weight gains, although at a diminishing rate (i.e. curvilinear response), especially when high-DMD silages are offered. Feeding a total mixed ration (TMR) offers no performance advantage over feeding silage and concentrates separately but may be a practical option where (home-grown) feed ingredients can be sourced and incorporated cost-effectively.

Energy is the most limiting nutrient in finishing diets. For finishing cattle, energy is expressed as Unité Fourragère Viande (UFV), where 1 UFV is equivalent to the net energy value of 1 kg air dried barley. The nutrient composition of a concentrate is more important than the specific ingredients used provided it is formulated to the same net energy (and protein) levels. Research conducted at Teagasc Grange has shown that equivalent animal intake and growth performance is obtained from concentrate rations containing contrasting energy sources (i.e. rapidly-fermentable starch (e.g. barley-based) vs. slowly-fermentable starch (e.g. maize-based) vs. ‘digestible’ fibre (e.g. pulps) -based concentrates), offered as a supplement to grass silage or ad libitum with silage, when formulated to be isoenergetic and isonitrogenous.

Indeed, research at Grange has shown that intake and growth performance of finishing steers was similar when offered grass silage ad libitum and supplementary (40-50% of dietary DM intake) concentrates based on maize meal, rolled wheat or rolled oats, compared to rolled barley. Similarly, the feeding value of protein-rich feed ingredients, namely flaked beans, flaked peas, maize distillers grains and corn gluten feed, were equivalent to each other when included in a cereal-based ration offered as a supplement to grass silage. In a second experiment, however, the feeding value of flaked beans was superior to peas.

Pattern of concentrate supplementation

Supplementing grass silage with an equivalent total quantity of concentrates offered at either a flat rate (e.g. 5 kg/head/day for the duration of the finishing period), a stepped regime (e.g. 2.5, 5.0 and 7.5 kg for first, second and third one-thirds of the finishing period) or ad libitum over the final half of the finishing period, resulted in large performance differences at different timepoints. Cattle offered the flat rate feeding started off with high live weight gains, which diminished over time; the stepped regime initially had lower live weight gains, which increased over time with increasing concentrate inclusion; and the ad libitum group had a very low live weight gain (0.2 kg/day) for the first half when offered solely silage followed by a very high live weight gain (1.9 kg/day) when offered concentrates ad libitum with grass silage. However, overall, pattern of concentrate feeding had no effect on live weight gain, carcass gain or carcass conformation score.  As concentrate inclusion progressed from flat rate, to stepped, to ad libitum, carcass fat score decreased significantly.

Managing high-concentrate feeding systems

High-concentrate diets, particularly cereal-based rations, increase the risk of digestive disorders such as ruminal acidosis. To minimise this risk, concentrates should be introduced gradually over a three- to four-week period. Animals should always have access to forage, which should account for at least 10% of total DM intake to maintain rumen health. Concentrates should be continuously available in ad libitum systems to prevent gorging and associated digestive upsets. Fresh, clean water should be freely available.

Duration of the finishing period

As the maintenance energy requirement of cattle is proportional to their metabolic body weight, more feed is required to put the same increment of live weight gain on a ‘heavy’ than on a ‘light’ animal. Furthermore, as slaughter weight increases, the proportion of fat in the gain increases – this is important because energetically, the accretion of fat tissue is less efficient than lean tissue, meaning that animals will require more feed to put on weight as they begin to deposit fat.

Daily live weight gain of cattle over the finishing period is not constant. In general, live weight gain is higher at the beginning and declines, often progressively, with increasing duration of finishing period, and this is associated with poorer feed efficiency. For example, research at Grange has shown that over a 132-day finishing period, live weight gain of suckler-bred steers offered grass silage ad libitum and 5 kg concentrate fresh weight daily, decreased from 1.13 kg/day to 0.77 kg/day, total DM intake increased from 9.9 kg to 10.3 kg/day and feed conversion ratio increased from 8.8 kg DM to 13.4 kg DM per kg live weight gain, between days 0-62 and days 63-132. In other words, 52% more feed was required to gain a kg of live weight in the second half compared to the first half of the finishing period.  To optimise feed efficiency, cattle should be drafted for slaughter once they reach a carcass fat score of 3=/3+, as this is the optimum market specification, and efficiency declines rapidly when animal fatness is excessive. Early-maturing breeds and heifers generally require shorter finishing periods due to their greater fat deposition potential at an earlier age, whereas late-maturing continental breeds and bulls typically require a longer period to achieve adequate carcass finish.

Beef budgets

Profitability in beef finishing systems depends on balancing purchase prices, animal performance, feed costs and carcass value. Budgets help farmers assess the suitability of different systems under current input and beef prices, while identifying the maximum affordable purchase price for stores or weanlings. Table 2 outlines a sample budget for a continental 24-month steer finishing system. This budget only serves as a general guide and should be adapted to individual farm conditions and market circumstances.

Table 2. Beef Budget 2025/2026 – Continental weanling-to-beef 24-month steer system

Assumptions: DMI at 2% of live weight; concentrates €350/ tonne FW; 72% DMD grass silage costing €45/t FW, grazed grass costing €0.10/kg DM equating to €204/animal over a 200-day grazing season; vaccinations, dosing and vet visits, €39/animal; levies and transport, €40/animal

Conclusions

Beef finishing systems should aim to achieve target carcass specifications at the youngest feasible age through use of high-quality forage and targeted concentrate supplementation. Overall, the most sustainable and profitable systems are those that consistently optimise forage quality, align nutrition with animal requirements, and calculate budgets within a clearly defined production system.

Compiled and edited by Mark McGee and Paul Crosson, Teagasc, Grange Animal & Grassland Research and Innovation Centre, and first published in BEEF2026 – Driving Sustainable Performance, additional reading from BEEF2026 is available here.