I do this as my living, but, this is my first few years and there is a lot of startup costs. Thankfully I do have my husband to "really" support us. I am fairly sure that 2008 I will see an actual profit on my tax returns. Business is picking up very quickly
I started as an horse show photographer and people do buy. Rated shows are worth doing(though exhausting) as people are used to paying $35 for an individual photo. The smaller shows people aren't willing to spend as much, You still get sales, as long as your product is good. It is a lot of work for the amount of return
I don't know what the coursing photographers are charging in Canada, but, around here, they charge $2.75 an original file. That is fine if that is a business model you can live with. I cannot. It is a hot/wet/long day sitting on a field with no shade. I watched him shoot when it was 102f with no shade.
I am also a dog sport person, finished my (then) 12m old whippet's ASFA Fch in 2 weekends at 12m. My daughter wants to start to do agility with my older bitch. My youngest whippet should be an amazing courser.
Your images are plenty good enough to sell. It is very hard to be at an event in a professional context and participate. It starts taking away the fun. Not to mention that you will need to start thinking about business licenses, insurance, paying taxes etc; and so on
And as far as event photography goes, everybody has a DSLR now. So, it is getting harder and harder to make it a worthwhile business. People like Dave have multiple proofing on site computers and I believe he also prints on site.
It looks easy and easy to make quick money. If you do it halfway and just cover entries, you could probably do that. Though, do check to see if there is an official photographer there. If there is, don't shoot and sell also. That will bite you on the butt down the road if you ever do want to do it as a profession