Whiskey Cobbler (It's all in the Whiskey Book 6) by Jen Talty

Heather Cobbler has dedicated her life to the love and care of the horses at Whiskey Ranch. Having been born and raised on the land, her loyalty runs thick and deep. So, when horses start getting sick on her watch, Heather will stop at nothing to find out who is harming these glorious creatures and why. Even if that means teaming up the veterinarian who has been hitting on her for nearly ten years and doesn’t know how to take no for an answer. Not much happened in the sleepy little town of Buhl, Idaho, and that’s exactly why Detective Crew Irvin had moved there from the big city. So, when it appears a horse is murdered out on the Whiskey Ranch, Crew wants to wrap it up neatly and quickly. That means slapping the cuffs on the super sexy ranch hand, Heather Cobbler. Crew’s detective skills might be rusty, but he doesn't have cobwebs for brains and Heather is about as guilty as the sky is pink. Only he can't prove it without putting his heart on the line.