Horses are usually vacinated yearly.
Once
Your horse should have a tetanus every year. It should be included in the 4 and 5 way vaccines from your vet or some feed and tack stores.
It depends: ask your vet.
Yes, donkeys often graze with horses.
That depends on the specific "5-way" vaccine that you are considering. There are several different vaccines on the market for horses that provide protection against 5 different disease and the combinations are not all the same.
ticks
To the best of my knowledge, there are no legally required vaccines for equids in California. However, individual shows, events or stables may require certain vaccines such as those for rabies, strangles, West Nile Virus, EEE/WEE/VEE, herpesvirus, etc. The AAEP (American Association of Equine Practitioners, the core association for equine veterinarians) advocates that all horses should receive Rabies, Tetanus, West Nile Virus, Easter, Western and possibly Venezuelan Equine Encephalomyelitis vaccines. Depending upon your horse's individual risk profile and geographic location, other vaccines may also be recommended by your veterinarian.
That depends on the horse's age, location (country, state, even county), reproductive status, use and management/stabling. For example, the commonly recommended vaccines for horses in the US are very different than for horses in the UK. This is why it is important to contact an equine veterinarian to have an appropriate vaccination regimen designed based on each horse's risk factors.
In horses, parturition(the birthing process) is often called "Droping the foal."
Vaccines do not prevent infection. Vaccines prepare the immune system to fight infection by allowing the immune system to produce antibodies to a specific invading organism, kill it, and remember it in the future. In vaccines, this organism is often weakened or dead. If the invading organism is found by the immune system in the future following immunization, the immune system remembers it and produces the specific antibodies needed to kill it quickly.
Yes. It helps the mare of course but it also boosts the foal's immunities. But talk to your vet first.
Edible vaccines are vaccines produced in plants genetically modified through bioengineering.