Actually, anti-toxin does come with some serious risks.
"There is a disease syndrome called “serum hepatitis” that affects horses. This is a very rare event and is linked to administration of equine serum origin products. About 20% of horses with idiopathi (unknown cause) acute hepatic disease (IAHD) show clinical signs of liver failure (anorexia, lethargy, jaundice) within 4 – 10 weeks after receiving an equine origin biologic – hence the name “serum” hepatitis 1. One of the most common equine serum origin products used in the field today is tetanus antitoxin. Many other equine serum products, including normal horse plasma, have also been linked to serum hepatitis 2, 3, 4. This link between equine serum origin products and hepatitis has been well documented for almost 90 years 6. The cause of serum hepatitis is not known 2, 5. As mentioned earlier, it is a very rare event (incidence is ~1:500,000 doses sold - based on Colorado Serum data), but “outbreaks” 1, 4 have been reported every few years with multiple horses in the same and sometimes different geographic areas involved. Some horses will develop hepatitis having never received an equine serum product before 1, 5. Some toxic plants, moldy corn and blue-green algae can also cause hepatitis 1. There is not an equine specific virus that causes hepatitis and there has been no causative agent identified in cases of serum hepatitis despite repeated attempts to do so 2, 5. Attempts to transmit the disease experimentally have also failed 2, 4, 5. The most plausible causative explanation/theory is a type III hypersensitivity reaction 1, 7 which is a type of allergic reaction where antigen-antibody complexes form in the liver which results in hepatitis and has a mortality rate of 50 – 83% once symptoms begin....Tetanus antitoxin is usually a very safe biologic that has its place in the equine world, but its use, like all biologics, is not without risk and serum hepatitis is a unique and very rare risk associated with equine serum products. For this reason it is wise for horse owners and veterinarians to be aware of these risk factors when using biologics and to understand when tetanus antitoxin is indicated vs. a tetanus toxoid booster. "--Randall J Berrier, DVM
Definitely if you are having to rely on feed store employees to pick your vaccines for you then you shouldn't be purchasing vaccines yourself. There is too much risk for missing a vital vaccine or being given the wrong product. People who work in feed and farm supply stores don't necessarily (or often) have any more knowledge about vaccinations or basic medical care of your horse than you do.
If you want to cut your vet bills by not having exam or farm call charges, simply pick up the vaccines from your vet and administer them yourself. Then you still have a record at your vet's office as to when vaccines were given and what was given and you have your vet's professional advice on what to give and he and his staff know what they are giving you.
