I'm a strong believer of MLV vaccines. If you use any killed vaccine, DO NOT forget the boosters. Most killed is only good for 6 months and is more expensive. MLV cannot be given to pregnant cows UNLESS she has been vaccinated with equal product within 12 months.
Lepto should be given 2 x a year.
For calves, I use BoviShield 5L5HB & OneShot Ultra at 3-5 months - also I deworm with both, Valbazen drench and Pour On. Then at 4-6 months, they get the BS 5L5HB & UltraChoice 8 (booster). BS does not need a booster, but you only get like 90% efficiency in any vaccine. By giving it again 30 days later, I feel confident they are 100% covered. Then I don't vaccinate until after weaning stress is over.
Spring calving cows get the BS in the fall and fall calving cows get BS in the spring. They all get Lepto shot - either spring or fall whichever they are not getting their BS.