Instructions:

1. Peel and finely chop the onion, carrot, and celery.
   
2. Heat the oil in a pot and sauté the vegetables over medium heat for a few minutes, stirring often.
   
3. Add the ground horse meat to the pot and cook for 5 minutes, stirring occasionally and breaking up the meat into small pieces.
   
4. Pour in the red wine, increase the heat, and let the alcohol evaporate.
   
5. Add the tomato puree and half a cup of water (about 120 ml), and stir well. Once the mixture begins to boil, lower the heat. Cover the pot with a lid slightly ajar (or completely if your lid has a steam hole) and cook the ragù for 3 hours, stirring occasionally and adding water if necessary to maintain the right consistency (it shouldn't be too thick).
   
6. Once cooked, season with salt and mix well.