A calf's immune system does not develop enough to be able to utilize vaccinations until he is approximately 3 months old, hence the importance of colostrum and passive immunity. I would not vaccinate before that age. To the best of my knowledge, this is true for all bovine's regardless of breed.
In my opinion they should at least get a blackleg vaccine, one lost calf pays for a lot of shots. Most vaccines state if vaccinated before 3 months to booster it later, that is the way we do it. We lost one once to blackleg that did not get vaccinated, right before weaning time found it dead. Not a cheap lesson.
I wouldn't let my kids go to schoool without vacinations, and I wouldn't let my calves/cattle out in a pasture without vacinations.
As far as time to do it: My vet said the same thing as above about the time to vacinate - does no good when they are just born - the absolute best thing for them is the cow's colostrum.
Around 3-4 months old is the time to run the calves at least through the chute and give them whatever your vet recommends for your area. With April calving I run the whole herd through the chute around mid July and everybody gets shots and wormer.
Waiting until they get sick is almost criminal to me when good vacines exist. The ROI on shots is also very good. It does not cost very much to do it right. jmho.
I would use the term "Rancher" loosely here. This person is either naive, lazy, no handling facilities, a serious tight-wad, stupid, or one of those idiots who likes to take chances. Personally, I'd stay at least 1/2 mile away from him/her, his/her equipment, or property...no telling what might be lurking on his/her place...blackleg, TB, brucellosis, anthrax, ebola, HIV, bird flu, every possible species of worm or parasite, etc.,etc. Then some wonder why the animals they buy at a sale barn end up sick or dying... And, I would not pay any attention to anything he/she said.
although there are some vets who don't keep up with the latest research, as well as some internet experts who only regurgitate what they have read in old textbooks or what they have heard from their pappy, there is plenty of modern research to indicate that vaccinating calves under the influence of maternal antibodies does indeed have a positive influence on immunity. this is known as a 'memory response' and is actually quite real. talk with researchers and they will confirm the value that this 'memory response' confers upon later vaccinations.
also, it's not really accurate to say that the immune system in young calves is not developed enough to utilize vaccines. it's actually more accurate to say that maternal antibodies interfere to some extent with the response to introduced organisms. in other words, the calf's immune system is functioning properly with the maternal antibodies and those maternal antibodies, for lack of a better word, 'cancel' to some extent the response from the vaccine. immune response is not always 'canceled' completely, however. also, even though calves vaccinated at young ages might not show a great titer response to the vaccine itself, when they are boostered at later ages they show an even greater immune response than those controls that were not vaccinated at an earlier age. this is the result of the aforementioned 'memory response' and is definitely something that has a dollar value, although hard to assess.
anecdotally, i have used thousands and thousands of doses of mlv's, often on calves as young as 1 week of age. in fact, most of us that vaccinate at branding are vaccinating calves under 3 months of age. i wouldn't spend the money on branding shots if i didn't feel like it was of significant value. i realize that i am not getting 100% immunity, but i am convinced that i am getting some immunity, along with the 'memory response' that helps confer added immunity later.
again anecdotally, in my experience calves that are vaccinated at branding, i.e. less than 3 months of age in most cases, show a response to boosters given at or just prior to weaning that results in treatments post-weaning of well under .1%. it's hard to argue with real results like that, so i suppose i will continue to 'waste' my money on early calfhood vaccinations.
keep in mind that if you wait until after 3 months of age to vaccinate calves, at some point you will lose a calf less than 3 months of age to something that you could have prevented. people that haven't lost those just haven't handled enough of them for the probabilities to catch up with them. my advice is to get vaccine into calves as early as you can, assuming that you follow the label directions and booster when they are older.
also keep in mind that no vaccine is ever 100% effective. the more shots you can get into an animal, the greater the immune response you will have. not only from boostering the initial shot in the calves that had a response, but in picking up the ones that had no response earlier.
a reminder is probably called for here: do not use mlv's on calves nursing bred cows unless the whole herd has been vaccinated with that mlv.