Horse worming

Our customer asked:

I have recently rescued a horse that I have been riding since March. During that time I know he hasn't been wormed at all, never mind regularly! He had been sharing a field with a least 5 other horses in the same situation, and on a field rotation with about another 25 horses... I have now made the decision to move him to another yard... I'm aware I need to worn him in order for them to take me on.. But I'm also concerned that he hasn't been wormed in so long so he may react bad. Please can you advice me what I should give him and for how long.. Also what do you recommend as a safe treatment programme as literature changes so frequently.

Our reply:

The ideal worming protocol varies depending on how many other horses share the same pasture, and how crowded they are, amongst other things. Generally it is best to collect some dung and send it to a lab (this is quite cheap) to check for any worms. Some mature horses develop a good immunity to worms and do not suffer much, even if they are never wormed. Other have more trouble. If your new yard requires a worm doe to be given, then I recommend using Equest horse wormer. It is a very effective and safe wormer, and has some slight environmental benefits too. After that, you will need to fit in with the worming regime used at the new yard, but worm egg counts are a good idea. They can save money on worming which is not needed too.