New self-propelled forage harvesters come with hefty price tags, but only about 500 are bought in the U.S. and Canada each year. That can make for heated competition among chopper makers.

Especially when one manufacturer commissions an independent study comparing its machines to one of its rivals.

Last fall, Deere & Co. hired Randy Clark of RCI Engineering, Lomira, WI, to test and compare its 7500 and 7700 self-propelled harvesters to Claas of America's 900 model. The Deere models' advertised peak horsepower is 570; the Claas', 605.

The study showed that the two manufacturers offered somewhat comparable harvesting capacity; Claas averaged 253 tons/hour, the JD 7500 chopped 248 tons/hour and the JD 7700, 247 tons/hour. The Deere machines, however, exhibited higher fuel efficiency — an average of 10-11% higher — and increased harvesting efficiency — 7.8% — over the Claas.

“The study doesn't prove that we're a head-and-shoulders winner over Claas,” says Tim Meister, Deere forage product marketing manager. “If you look at some of the things, such as time to set the shearbar, it shows that Claas has an advantage.”

Yet Bob Armstrong, Claas of America's product marketing manager, questioned the study's validity and wondered if Clark, a former Deere design engineer, was biased. So did Phil Wright, hay and forage product specialist with New Holland, another chopper manufacturer.

“In doing our own tests, as a manufacturer comparing against competition, we try to make it as neutral an environment as possible,” comments Armstrong. Clark says he used machines of the same vintage and wear as well as operators experienced in the models they ran in the test.

Two machines of each model chopped corn silage on the same 250-acre field. “Each machine chopped about six loads at each of the lengths of cut,” says Clark, who adds that being biased toward Deere would be bad business for his company.

A few results Armstrong and Wright questioned were: that the harvest capacity of the wider model 7700 was lower than that of the 7500, and that average machine capacity decreased on the 7700 when length of cut increased.

Clark's reply: The differences were within 3% and considered “negligible” because of differences in operators, field conditions and the like. To see the study's full results, visit

“Those kinds of (independent) studies need to be done,” Wright says. “Manufacturers have a tendency to talk about all of these things that aren't always true. I like competition; I thrive on it as long as it's fair and truthful.”