Below are guidelines for vets who don't have gas anaesthetic machines
e.g. animal shelter work in the field and cost considerations. Zoletil, Domitor and isoflurane are costly.
1. XYLAZINE + ZOLETIL ANAESTHESIA
Xylazine 0.1 ml + Zoletil 100 0.1 ml in one syringe IM
If insufficient, top up with Zoletil 0.01 ml IV to effect.
In one case of a 5kg male
cat, I topped up with Zoletil 100 at 0.05 ml + 0.1 ml saline IV after 10 minutes of the xylazine 0.1 ml + Zoletil 0.1 ml IM combination. Effective analgesia for neuter.
2. XYLAZINE + KETAMINE
Xylazine 0.1 ml + Ketamine 0.4 ml in one syringe IM. If insufficient, top up with Zoletil 0.01 ml IV to effect.
For cats 4-6 kg, double the above dosage IM.
I use this formula frequently for spay and neuter of cats without problems.
Duration of anaesthesia is half an hour.
3. DOMITOR + XYLAZINE
Domitor 0.1 ml + Xylazine 0.1 ml in one syringe IM.
If insufficient, top up with Zoletil 0.01 ml IV to effect. Domitor is expensive for stray cat spays.
I have not used this before.
4. IF USED ALONE, adverse effects are as follows:
1. Insufficient analgesia. Needs to top up IV.
2. Salivation and legs rigid (ketamine IM)
3. Wakes up fast
Combined with xylazine will make the cat sleep longer.