I always vaccinate my horses with tetanus toxoid as part of the yearly vaccinations, but give tetanus antitoxin any time they get an injury, etc. I haul to places where we get around other horses, so I vaccinate for West Nile, all 3 sleeping sickness, the influenzas, rhino, and strangles, too. I use the weakened live virus vaccines that I get from the vet, rather than the killed virus versions you can get online or at TSC, etc. Probably costs about $35 or so per year per horse for all of this. Cheapest money you can spend on your horses. I might be a little OCD about it, but If I take one in for training, they have to give me a vet certificate and I want the vaccinations to be between 30 days and 6 months . Even if they have been on a yearly vaccination schedule, if it has been 7-11 months since they were vaccinated, I make them do it again 30 days before I take them in. I want their Coggins test to be within 6 months, too, even though GA just requires an annual Coggins.I attended a food animal-oriented veterinary continuing education meeting a couple of weeks back.
It takes a minimum of 17 days for any detectible anti-tetanus antibodies to be produced following an initial dose of tetanus toxoid (as would be present in the 8- or 9-way bacterin/toxoid). Booster, given after that point, will boost (that's why we call it that) antibody levels exponentially.
So... if you're giving an initial dose at the same time as banding... you're essentially 'rolling the dice' and hoping your calves just don't develop tetanus, because they are not going to be immune by the time the organisms would normally be producing the toxin in those devitalized tissues. In that scenario, if you don't lose any, you just had some good luck.
Now... if you're giving a dose of tetanus antitoxin AND the initial tetanus toxoid at the time of banding, the antitoxin will provide 'immediate' protection, while not interfering with response to the toxoid. I'd still give the booster 3-4 weeks later...
My own preference is to give an inital dose of toxoid, with booster at 3-4 weeks, then band. Ideally, you'd wait 3 weeks after the booster for maximum protection, but I have just banded at the time I administered the booster dose.
As an aside... the first case of tetanus I ever saw was in one of my own steers that I knife-cut at about 350 lbs; found him 'sawhorsed' out in the pasture, 2 weeks later.
We lost a 4-month old heifer to tetanus once; never determined her exposure, but we started using an 8- or 9 way Clostridial bacterin/toxoid containing tetanus, on everything from that point on.
While the tetanus organism and it's spores are widely distributed in nature, it also appears to be part of the normal gut flora of some horses, so if you have one-toed hayburners around, there may be a greater likelihood that you'll encounter tetanus in your cattle.
Granted, It is a lot easier on the wallet to run a fully comprehensive program like this for 6-8 horses, than it would be on a 200 head cow herd, but at todays prices, losing even one would have paid for the vaccines. That being said, in over 30 years fooling with the Corrientes, we have never given one vaccine or one wormer to any of them. In the past we calved the 100-120 cow herd in February, and by about this time of year, we'd cut or band the bull calves. With this herd now, calving between January and end of May or so, we are going to start with the ones at the end of this month, giving them a tetanus anti toxin when we turn the bulls into steers. Now those 5 nurse cows and their calves, we are keeping them on a vaccination and worming regimen.