For young cats and dogs, surgery does not require a great deal of home preparation. The most important thing is to ensure that their stomachs are empty when you drop them off for the operations. Food or water in the stomach may cause them to regurgitate during the procedure, which can lead to pneumonia or throat problems. Your veterinarian should provide specific fasting instructions prior to the surgery.
Some veterinarians prescribe oral pain medications or antibiotics to be given the day before surgery. These are not used in all cases. If your vet has prescribed these medications, be sure to follow the instructions carefully. If your pets are on regular medications that have not been prescribed specifically for the surgeries, ask your veterinarian whether they should be administered in the period leading up to the operations.
Although you did not ask about the days after the surgeries, I have some advice to offer on the matter. Monitor your petsappetites, thirst and production of urine and feces carefully. It is not abnormal to have a mildly depressed appetite for 24 hours after surgery. Mild constipation is also common. However, call your vet if your pet experiences complete loss of appetite or total inability to urinate or defecate.
As well, monitor your petsactivity levels. They should be kept quiet for several days after surgery. Do not let them play roughly together. And, call your vet if either one seems exceptionally lethargic or inactive.
All pets need medications to treat pain after surgery. Follow your veterinarians instructions for these medicines.
Check the incisions daily. Call your vet if you notice swelling, redness, discharge, a strange odor, or an open area on the incision. Do not allow your pets to lick their incisions.
I have one final piece of advice. The vast majority of spays and neuters go well and do not lead to complications. Nonetheless, do not hesitate to call your vet if you have any questions or suspect that something might be wrong. It is better to be safe than sorry.