The months of April and May are an ideal times for routine herd health work for the cattle producer. Calves receive antibodies through their mother's colostrum that help to give them passive immunity from disease, but by three months of age, this maternal protection is fading. This is an ideal time to vaccinate January and February calves to help jump-start their immune system.

As well, parasites that have been dormant during winter, are now becoming active, and will infest their hosts. By deworming now, you will keep parasite populations lower into fall. This strategic deworming, manages parasites on the pasture, not in the cow.

Vaccinations with a clostridial vaccine will help to reduce incidence of blackleg and other soil born infections, and a respiratory vaccination will give protection against the major bovine respiratory diseases. Modified live respiratory vaccines give more protection, than killed types, but can cause abortions, so make sure the product is safe for pregnant, or lactating cows. These are best administered to open cows, as even giving a modified live vaccine to the calf can cause abortion in the mother who is bred back.

Most vaccines require two shots initially, then an annual booster. If you aren't going to give the second shot, there is no need to bother with the first, as you'll have very little protection. Only giving one shot of a two shot series won’t give enough protection, and can also interfere with later boosters.