Let's Talk Organics: Making Quality Grass Silage on Organic Farms

Why It Matters

High‑quality silage cuts costly concentrate supplementation and boosts animal growth, directly enhancing farm profitability in organic livestock operations.

Key Takeaways

• Silage quality varies widely across organic farms, affecting performance.
• Top 20% silage meets DMD >70%, energy ≥10 MJ/kg, protein ≥14%.
• Poor silage reduces weight gain, requiring up to three times more concentrate.
• Better silage can cut supplementation costs by half, boosting profit.
• Regular silage analysis enables targeted improvements and cost savings.

Summary

The webinar focused on producing high‑quality grass silage for organic livestock operations and the financial impact of silage variability. Marianne presented data from 93 organic farms, revealing a stark contrast between the top and bottom 20 percent of silage samples. Top‑tier silage consistently exceeded the target dry‑matter digestibility (DMD) of 70%, metabolizable energy of 10 MJ kg⁻¹, and crude protein of 14‑16%, while the poorest samples fell to 61% DMD, 8.6 MJ kg⁻¹ energy, and 10% protein.

These nutritional gaps translate directly into animal performance. High‑quality silage supported near‑target daily weight gains of 0.5 kg for weanlings, whereas low‑quality silage stalled growth, forcing farmers to add up to three kilograms of concentrate per animal per day, often with higher‑protein (18%) feeds. The cost differential is stark: achieving a 1 kg daily gain on poor silage required €420 per animal versus €240 with premium silage, a €5,000 gap for a 30‑head finishing herd.

Marianne emphasized that regular silage testing—tracking DMD, energy, and protein—allows producers to pinpoint deficiencies and adjust harvest, ensiling, or supplementation strategies. By aligning silage quality with nutritional targets, farms can reduce concentrate use, improve milk yields or weight gains, and capture additional revenue—illustrated by an estimated €470 extra per weanling sold when growth targets are met.

The broader implication is that silage quality is a lever for profitability on organic farms. Investing in analysis and best‑practice silage production can lower feed costs, accelerate animal growth, and ultimately increase farm margins, reinforcing the economic case for rigorous feed management even in organic systems.

Original Description

The Teagasc Organics team hosted a webinar on Wednesday, 1 April which focused on making quality grass silage on organic farms. Webinar host Elaine Leavy, Teagasc Organic Specialist was joined by Marianne Mulhall and Cathal McCauley, Teagasc Organic Advisors.

Marianne discussed the impact of silage quality on animal performance, based off the results of samples taken on organic farms at the end of 2025.

Cathal provided an overview of how to make enough good quality silage on organic farms.

Watch back previous Let's Talk Organic webinars here https://teagasc.ie/rural-economy/organics/webinars/