Kelpies in Australia work cattle too. My experience with them is that they are all individuals, no matter what breed. My kelpies are all very different (like people) with different skill sets. They vary on yard versus paddock ability, how much push, how much eye, how much bark, whether they'll back the sheep and if they'll go under them down the race. Some are no good with cattle some are no good with sheep, some are pretty hopeless altogether and some are stars all-round.
For cattle you'll need one with decent push and not fearful.Nevertheless, kelpies are widely used with cattle in Australia.
I have given up on getting puppies to train, as I won't shoot unsuitable dogs. I now only buy ready-trained dogs that I try out to see that they do what I need. In Australia, this is about $1000 to $2000 for a dog about 2 year old.
And don't think they won't transfer to you becasue you haven't had them since a pup. Of course there could be some that don't adapt well, but I've not heard it happen. Mine sleep in or on bed with hubby and me - as far as they are concerned they are now in doggy heaven. I just got a 7 year old excellent yard dog a year or so ago, who was an outside working dog, lived on a chain etc. Her previous owner left and she looked totally bewildered for about one minute when I started giving her commands, then she just started working and has never looked back. She has now discovered the joys of having her ears and face poked and massaged and makes cute snorty sounds of contentment.
And such "spoiling" makes no difference either. My other kelpie girl lived in a battery of kennels (but was well cared for and exercised), never went in a house, was never fed at the table etc, was 2 or so when I got her, she is now a 7 year old. All our dogs come inside in the evening and she sleeps on the bed and gets kissed and cuddled a lot, and gets given tidbits to eat - she has not become disobedient, she has in fact become even better with maturity and ongoing reinforcement of her training.
Kelpies and collies are quite different too. If you are used to collies you need a change of mindset to work with kelpies. Good Border Collies in general tend to be more command driven and wait for direction. Good Kelpies tend to want to think for themselves more, so that they will appear to be less obedient than a collie.
I hope you can find a good one.