This sounds like a difficult dilemma. The older horse often begins to fail to thrive at Rufus' age. They require more intense feeding regimens (often requiring a complete feed +/- forage alternatives), they sometimes don't even have teeth yet, and they can begin to have organ system failures (kidneys, liver, heart, and/or neuromuscular). The latter can all negatively impact the horse's body condition, strength, and comfort.

When a horse gets to the point that they can no longer maintain at least a body condition score of 4/9, and begins to have trouble rising, something needs to be done. 1) You can attempt to identify an underlying cause of the failure to thrive by veterinary exam, blood work, and urinalysis. 2) You can make the decision to euthanize.

Occasionally, if you opt for the prior, a change can be made to the diet/vitamin ration, or a manageable medical problem (like equine cushings disease or equine lower motor neuron disease) is identified that can be appropriately addressed, returning the horse to adequate health. That is great! Other times, no major abnormality is found (this brings you back to just feeding more or euthanizing to prevent slow decline/starvation). And still other times problems are identified that are not manageable, and often make owner more sure that the end is near for their friend. If this is the case, then euthanasia should again be heavily considered.

On to the second part of your question... euthanasia and how to do it. Personally, I prefer a planned euthanasia as opposed to letting your horse get down without being able to get up. The latter situation is extremely stressful on the horse, the owner and the veterinarian. So regardless of which method you choose, you and your horse are better off to do a planned euthanasia.

The main difference between methods is really personal preference and cost. Euthanizing with pentobarbitol (OD of an anesthetic agent) is more costly and involves giving a large IV injectable dose. The horse collapses when succumbing to anesthesia, and then the heart stops (after seconds to minutes). The horse may do some irregular, gasping breathing during this procedure and rarely may paddle the limbs or vocalize. Some veterinarians will choose to sedate (and sometimes place an IV catheter) a horse prior to administering the euthanizing drug if a horse has a history of being bad for IV injections. Shooting a horse is also an acceptable means of euthanasia if done properly. Sedation can help with this as the horse needs to stand still while the barrel of the gun is placed in the appropriate location on the forehead, and the gun is discharged. Once shot in the appropriate place (draw two lines, one from each earbase to the inside corner of the opposite eye... X marks the desired entry point with the shot going perpendicular to the skull), the horse is literally deceased before he begins to fall. There is occasionally some muscle twitching, but no vocalization or weird breathing. The biggest problem with shooting a horse is having it done in the right spot. If this isn't done correctly, the horse just gets shot in the sinuses which is both messy and painful.

You can find more information on deciding when to euthanize at my practice website:

http://www.cedarrunvet.com/Home_files/page0011.htm

I hope that you feel more informed on the process and that I have given you a useful tool/advice on when to make the decision. Please let me know if you have follow-up questions. Otherwise, please accept my answer so that I may be compensated.