Any Way to Import Splines to DXF?

Hi, y'all. I read you guys all the time.

I tried to search here for my answer, but no-go.

I've sent my Amada guy many drawings- lines and circles. Geometric shapes. All worked well

But I think this is the first time, I sent him a bird. We do custom sheet metal work, on occasion, and I had to draw a big bird...Needless to say, it had a LOT of splines.

When he opened it in dxf, on the Amada, the only lines on his screeen were straight and radii.   But a couple of small splines seemed to form.

I tried "save splines as polylines", and a couple more appeared. But still, half of drawing is missing?

Any fix? (Bear in mind I'm still a semi-rookie)

Thanks as always, Mike