Vaccinating pregnant cows: Reproduction

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When a cow is in the chute for pregnancy checking, many cow-calf producers take advantage of the opportunity to perform other necessary procedures to get their cows ready for the winter and the subsequent calving season. For some producers, vaccinating cows is on this list of tasks. But should it be? 

There are two main disease categories for which most producers vaccinate cows. One of them is to boost colostrum quality by vaccinating against calf scours organisms. The other is for infectious reproductive pathogens such as IBR, BVDV, leptospirosis and vibriosis. 

Most vaccines against reproductive pathogens are labeled to be given prior to breeding. In some herds, however, management and labor constraints result in situations where preg-check time is the only chance to get the cows vaccinated. 

While it may be convenient, vaccinating for reproductive diseases during gestation is not exactly ideal. Most of the reproductive diseases we can vaccinate for can have substantial effects early (first two months or earlier) in gestation. Vaccinating a spring-calving cow herd in November means that 7-8 months might elapse between vaccination and the beginning of the next breeding season. This is long enough for the vaccine’s effects to have waned, as peak immunity probably occurs within a couple weeks of vaccination and then slowly declines. For this reason, gestational reproductive vaccine programs lack optimal timing.

It should be pointed out that there is little downside to using reproductive vaccines during pregnancy, if — and this is a big “if” — killed vaccines are used.  Vaccinating the herd during gestation with a killed reproductive vaccine will probably provide the herd a better level of protection than not vaccinating at all. 

In recent years, several vaccine manufacturers have promoted using modified live vaccines (MLV) in pregnant cow vaccination programs. It has long been known that administering modified live IBR vaccines to pregnant cows will result in abortions. This latest recommendation is therefore given with the caveat that animals must have been properly vaccinated pre-breeding that year with the same MLV vaccine. 

However, evidence is mounting that this practice is a bad idea.Stories of devastating abortion storms following pregnant cow MLV vaccination exist. These initially were noted to occur as a result of producers not following the label precautions regarding properly vaccinating cows with the same product before breeding the first year. But in recent years reports of abortion storms in cattle herds using MLV vaccines according to the label directions have surfaced (O’Toole, et al), making even label use of these vaccines suspect. 

Cattle producers know how difficult it is to maintain good reproductive rates in a cow herd when everything goes right. Given current information, it seems that the risk of using MLV vaccines in pregnant cows is not anywhere near the benefits that may be gained. Producers with questions about their vaccine program should consult with their veterinarian.

Source: Russ Daly

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Dr Dan    
Ohio  |  November, 01, 2012 at 04:33 PM

We have been using MLV in preg cows and have not had a problem. The results that have been quoted are from a "test" that was not scientific and makes presumptions that are not valid

TX Cowman    
Colorado  |  November, 01, 2012 at 04:52 PM

I am really supprised that a publication like Drovers would let an article with such little basis in scientific fact onto its pages! MLV vaccines that are "bred cow safe" have been available for several years. If used according to lable directions, they have been found, scientificly, to be superior to comparable Killed vaccines. Lets spread information that can be backed up, not cause panic.

Dr Roy    
SE South Dakota  |  November, 02, 2012 at 11:45 AM

We have been using the MLV product on pregnant cows ever since the products became available but we adhere to the label. We have not had any reported abortions in the last 5- 7 years or however long it has been on the market.

earl aalseth    
November, 03, 2012 at 01:20 AM

russ this is not a responsible story that you have written. You need to do much more investigation on this topic to understand what you are talking about all the pro and cons and what is necessary to use MLV vaccines in pregnant cows. the dairy industry does not need this type of confusing reporting-inaccurate facts can actually do harm.

SD rancher    
South Dakota  |  November, 04, 2012 at 08:51 PM

Well said!! Our industry has always been a group of people who believe that your word is your bond and a handshake is better than most lawyer produced paper. It really disappoints me when a publucation that i frequently read front to back would print an article that flies in the face of established husbandry without some valid research to authenicity.

texas  |  November, 05, 2012 at 03:53 PM

Give me one example of a verifiable "abortion storm" from using MLV vaccines used according to lable. This is one area where we can make a difference in this business. We need to look at the facts and move on into the 21st century. Provide "one" example!

Vet Student    
iowa  |  November, 06, 2012 at 09:35 AM

MLV vaccines have been used for years in pregnant cows and the vast majority have never seemed to have any problems, however, some have and that is a problem. As a current veterinary student they are teaching us that the use of MLV vaccines in pregnant animals is no longer the normal. Check out the studying done by the University of Wyoming that was published in JAVMA.

cowdoc lana    
Michigan  |  November, 06, 2012 at 06:44 PM

The study referred to by the vet student is actually a report where a cohort of synchronized, AI'ed, and confirmed 7-8 mo pg by ultrasound heifers were vaccinated according to label instructions with MLV. This was a university herd and the heifers were Angus X. Abortions began at 32 d after vaccination - 8 if 55 heifers aborted 32 to 55 days after vaccination. Six aborted fetuses were submitted for necropsy. "Immunohistochemical analysis revealed the presence of BoHV-1 antigen in multiple tissues; it was most abundant in liver, kidney, and lung tissues. Furthermore, BoHV-1 was isolated from pooled tissues (liver, lungs, spleen, kidneys, and placenta) obtained from a fetus that had been expelled 47 days after vaccination of one of the heifers." Similar linked events have been reported in Wyoming, Texas, Colorado and SD. It is impossible to distinguish the vaccine strain of bovine herpes 1 from the field strain. The authors conclude "Although most post vaccination abortions appear to reflect inadvertent extralabel use of BoHV-1 vaccines by owners and veterinarians, some involve appropriately vaccinated heifers. Until there is a method to distinguish vaccine strains from field strains of BoHV-1, diagnosticians will be unable to confirm whether an episode like that described in the present report reflects a wider problem due to vaccine-induced reproductive failure." Novartis technical update July 2012 "This peer-reviewed article provides the latest and strongest evidence to date that MLVs can cause abortions in pregnant heifers—even when administered following label directions." Perhaps one should look a little further before shooting the messenger -

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