The parts most likely to be affected are an animal's foot pads and belly, which have less fur than other areas and have the most contact with cold surfaces.
(The parts most likely; to be affected; ) (The parts most likely to be affected; are; an animal's foot pads and belly, which have less fur than other areas and have the most contact with cold surfaces) (an animal's foot pads and belly; have; less fur than other areas) (an animal's foot pads and belly; have; the most contact with cold surfaces)
The parts most likely The parts most likely to be affected an animal's foot pads and belly an animal's foot pads and belly
to be affected are have have
an animal's foot pads and belly, which have less fur than other areas and have the most contact with cold surfaces
less fur than other areas
the most contact with cold surfaces