Shot placement has everything to do with the blood trail, as experienced. If too high all/most the blood remains within the animal and does not leak out to give a good blood trail. I arrowed a deer that produced similar results...no blood to speak of for over 60 yards, but piled up dead within 100. Also as mentioned animal position and animal condition will have its effects of covering the wounds and preventing a good blood trails.
As mentioned, a single experience is not a realistic sample of overall performance. Do not lose faith in your rifle/ammunition combination too quickly.
And if you are really concerned and want to ensure good blood trails every single time an animal runs after the shot (the norm, not the exception, regardless what people show on tv or claim on-line), then a larger caliber placed lower in the vitals (lower third of chest) will potentially provide such a result.
Don't get me wrong, I love the 6.5's! My favourite is the Swede (on my 4th rifle), and I still have my Creedmoor. Have also owned rifles in 260 Rem and 6.5x284. Next rifle added to the stable will be a 6.5 PRC. Have never had an issue or disappointment on game with a 6.5 in28 years of using them. Just plain fun to shoot!
As for does vs bucks...if you have followed the successful game management practices used in several other countries around the world (but unfortunately not in Canada to the same extent, if at all), a healthy buck

oe (or bull:cow) ratio is required for healthy herds and fawn/calf recruitment. Shooting all the bucks and no does means there aren't enough bucks required to ensure the does are properly covered to maximize fawn production.
An equally important factor that is often overlooked in this equation, is managing the predator populations too.