Drones provide high-tech way of measuring bunk silo feed

Farm Progress covered Aurox’s drone-based bunker silo measurement work in a 2019 piece that has held up well — most of the technical points are still the right ones to make.

Read the original Farm Progress article → Drones provide high-tech way of measuring bunk silo feed

Why measuring bunker silo feed is hard

Bunker silos look like they should be easy to measure. Three walls, one open face, a flat-ish top — math, right?

In practice, bunkers are one of the harder silage storage systems to measure accurately:

1. The top is rarely flat. Crowned piles, settling, and uneven feedout produce a complex top surface that a tape measure cannot describe.
2. Density varies by depth. Packing density is highest at the bottom and lowest at the top. A simple volume × density estimate misses meaningful tonnage.
3. The face moves daily. Feedout shaves the face back unpredictably, so any inventory number is stale within hours.
4. Manual measurement is dangerous. Probing or measuring near the face exposes people to silage avalanches — a meaningful safety concern that often pushes farms to skip the measurement entirely.

The conventional fix has been to weigh harvest loads, weigh feedout loads, and back into inventory by subtraction. The error compounds across thousands of loads, so dairies end up running on multi-month-old estimates that drift further from reality every week.

How drones changed the math

A drone flying a structured grid pattern at 50–100 feet, taking ~80% overlapping images, produces enough data to build a centimeter-resolution 3D model of the entire bunker. From that model, volume measurements are direct rather than estimated — the software measures the pile, not a simplified geometric stand-in.

Three things make the workflow trustworthy enough for dairy operations:

• Ground Control Points (GCPs). Surveyed reference markers placed around the bunker before the flight. They eliminate the drift that plagues unverified drone volumetrics.
• Repeated flights at known intervals. Volume change between flights, integrated with feedout records, reveals shrink at the pile level with high confidence.
• Sampled density. The 3D model gives you volume; targeted density sampling at the face turns volume into tonnage.

The Farm Progress piece highlighted the safety angle: drones move people away from the face. As the Vitaplus team in the article put it, the value isn’t just better numbers — it’s that no one needs to walk up to the face anymore.

Bunker silo feed measurement, today

Since the article was published, the workflow has matured into a complete software product. SilagePlan handles the drone imagery upload, the photogrammetry, the volume measurement, the density tracking, and the run-out forecasting in a single workflow. Farms that don’t fly drones can use 2.5D satellite mapping to measure piles from a browser.

The economic argument has only gotten stronger:

• A 2,500-cow dairy at modern $6.50/cow/day rations carries roughly $6 million per year in feed cost.
• Reducing feed-system shrink by 5 percentage points on that operation is $300,000 of recovered margin annually (each point = 1% of the annual feed bill).
• Drone measurement is a four-figure annual investment.

That ratio is why bunker silo drone measurement has gone from novelty to standard practice on most large dairies in the US and Canada.

Where the conversation is going next

The next frontier in bunker silo measurement is integration: connecting drone-based inventory to ration management, harvest planning, and feed-purchase decisions automatically. SilagePlan customers already use inventory data to anticipate run-out dates, plan ration transitions, and identify which bunkers consistently lose more than the operation average.

The drone is the front door. The data flow it unlocks is the value.

Further reading: The Importance of Measuring Silage Shrink · Accurate Forage Inventory: Will Any Drone Work? · Drones on Dairy Farms — Practical Guide · Bunk Silo (glossary) · SilagePlan