This is the 7495th most frequent Polish word.
końskich
"Końskich" means "of horses" or "horses' (related to horses)."
In this sentence, 'końskich' is the genitive plural form referring to characteristics belong to horses.
Lubię zapach końskich grzyw i sierści.
I like the smell of horses' manes and fur.
Here, 'końskich' is used as a possessive adjective describing attributes typically associated with horses.
W gospodarstwie mamy kilka końskich narowków.
On the farm, we have several horses' habits.
In this case, 'końskich' metaphorically describes a level of strength and durability comparable to that of a horse.