Meanwhile, Briggs and Tatum are working on an oral vaccine that can be given to animals via their feed. Some of the calves received the oral vaccine 4 days before shipping and others didn't. All of the calves fed the oral vaccine were protected, while 10 non-vaccinated calves died from pneumonia. If proved effective, producers might find that feeding the vaccine is easier and less time-consuming than intramuscular injections. Heifer Development, Selection and Breeding By Lochrane A. Gary Developing replacement heifers is a critical element to improving reproductive performance in a herd.
Many managers fail to recognize how important it is to keep heifers growing after weaning.
The emphasis should be placed on skeletal growth more than just weight gain. The period from weaning at 5-9 months of age to breeding at 15 months is critical if you expect a high percentage to conceive. Heifers selected for breeding should be born during the first half of the calving season. These heifers should be older, heavier and out of the more fertile cows. They should have a better chance of reaching puberty and conceiving early.