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Veterinarian View | August 2023

Overview of Preconditioning Programs For Optimum Calf Value

contributed article by Dr. Vince Collison, Collison Embryo and Veterinary Services,

Rockwell City, Iowa


It is getting to be the time of year when we should start thinking about preconditioning calves. With historic calf prices, it’s even more important to do what we can to maintain calf health.


Preconditioning Vaccines

When we give our preconditioning vaccines to the calves it is important to have the calves be in their best physiological state to get the best results. This would probably be while the calf is on grass and still nursing its dam. At this time the calf is in a clean wide-open environment and has not undergone any stress from weaning.


As calves reach the age of 4 to 6 months, their maternal antibodies from colostrum are going to start to wane. This is one of the reasons why we will see more respiratory disease in weaned or newly purchased calves. By giving the first set of preconditioning vaccines preweaning, we can initiate some immunity prior to all of their maternal antibodies regressing. Ideally, calves will be 4 to 5 months of age at the time vaccine is given. The other advantage to doing it at this time, is that you can reap some of the benefit at weaning as well as the future buyer of the calves.


Vaccine Recommendations

Our recommendations for preconditioning still are the 5-way viral vaccine along with a vaccination for 7-way Clostridium and H. somnus. We also like to deworm and treat for external parasites during the first round of vaccinations. Parasites are also a major cause of stress and immune suppression. Many producers want to wait to deworm after weaning since calves will be still on cows that are not treated for parasites. My feeling is that by deworming during the first round prior to weaning, your calves will have a better response to the vaccines due to the reduction of stress from parasitism. I am also amazed at how much calves will bloom prior to giving the second round of booster vaccine 2 to 3 weeks later, giving them even more advantage at weaning time.


Any surgeries that need to be done such as castrations or dehorning are best performed preweaning as well. Often producers are concerned with flies when performing these procedures in August and early September, but in my experience if you spray these surgical wounds with a screw worm spray they will heal very nicely.


Provide Mineral

Make sure that calves have had access to a good mineral prior to the time of preconditioning. If they have not, you may want to consider giving an injectable or oral drench trace mineral at the time of the first vaccinations to help the immune response. Also, response to vaccinations can deplete some of the trace mineral stores in the calf’s body.


Modified Live Vaccines

For the 5-way vaccines we still prefer to give modified live vaccine. This is what the buyers want when they buy calves and is a requirement if performing vaccinations for the Iowa Gold tag program. If using modified live 5-way on calves still nursing cows, consult your veterinarian to see what your options are and what will work best in your case. Also, on the viral vaccines we often are asked if we should give an intranasal product in conjunction with an injectable product. In my experience this is not necessary and can be too stressful, causing the calves to be set back excessively. At this age we feel the injectable viral vaccines are adequate.


When we booster calves, this is often done at weaning. At this point we recommend just giving a modified live 5-way viral and a 7-way/ Somnus for boosters. Or even just the 5-way viral by itself. By doing all of the other work on the cow, we get the booster vaccinations down to just 1 or 2 injections at weaning, making it a pretty simple process.


Coccidia Prevention

Also, during the post weaning phase a coccidiostat such as Amprolium can be fed to prevent the effects of coccidia. If a producer has had any problems with coccidia in calves, it can be prevented fairly well with this feed additive and it does not require a VFD. In addition to causing bloody stools, coccidia can also cause calves to be more prone to respiratory disease due to immune system suppression.


It is important for producers to work closely with their herd veterinarian prior to weaning to develop a program that works the best for their herd. Your nutrition, environment, closed herd or open herd are some of the many factors that can affect what you do for your herd and how well they respond. The herd veterinarian is there to help assess your program and determine what is best for your herd.



Dr. Vince Collison is co-owner of Collison Embryo and Veterinary Services PAC

in Rockwell City, Iowa.

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