MLV Vs. KilledMLV Vs. Killed
Used properly, modified-live vaccine corrals diseases and prevents reproductive problems.
February 25, 2013
By following the modified-live vaccine (MLV) label when vaccinating cows and first-calf heifers, producers can prevent diseases that can cause profit-killing respiratory and reproductive problems.
Dr. Doug Ensley, Professional Services Veterinarian at Boehringer Ingelheim Vetmedica, Inc. (BIVI), says ranchers can be confident that a properly used MLV will provide protection their cows and heifers need to prevent infectious bovine rhinotracheitis (IBR) and bovine viral diarrhea (BVD).
“An MLV contains living organisms, with no disease-carrying capacity,” Ensley says. “As a producer, you get a balanced immune response to IBR and BVD from an MLV as compared to a killed vaccine (KV).
“When a KV is administered, it puts a large number of killed virus into the animal. Animals vaccinated with a killed vaccine require two doses for protection and the immune response is generally not as balanced as you get with an MLV, so it takes longer to obtain that good protection.”
With BIVI’s EXPRESS® FP vaccine line, the producer has an MLV vaccine that provides protection against the major reproductive diseases such as IBR, BVD and Lepto hardjo-bovis, providing excellent fetal protection. “EXPRESS FP provides mama cows with broad protection against these viruses,” Ensley says. “That protection results in healthy mama cows and heifers that have healthy calves ready to grow.”
Ensley addressed a concern among some that scheduled reproduction can be altered by MLV. “Timely use of an MLV, according to its label, will actually aid in the prevention of abortion due to IBR,” Ensley says. “Use of an MLV will promote healthier calves that grow more efficiently and provide better return.”
According to EXPRESS FP vaccine labels, Ensley says cows that have not received the MLV within the previous 12 months should be vaccinated pre-breeding. “I’d like to see those cows vaccinated with the MLV 30 days before bulls are turned in,” he says. “Any disease impact is often early following breeding. They can impact conception and/or cause fetal loss early on. So we want the cow vaccinated as soon as possible.”
Of course, some ranches are not able to gather cows and get them vaccinated pre-breeding. “You can use the MLV in those cows at preg-check time, if they have been vaccinated with the MLV within the past 12 months.
“Timing is essential in all cases. For heifers that have never seen the vaccine, we really want to stress that the MLV be administered at least 30 days pre-breeding.”
There are many value-added calf (VAC) programs used by ranchers to help assure calves are healthy early on. Many stocker buyers, and especially feedyard operations, recommend these VAC programs. They see the value of a good vaccination program at any ranch or stocker animal health program.
Losses from unvaccinated females can happen early and often, such as those from IBR infections. Losses from cows that abort calves can’t be recovered. When cows abort calves due to an IBR infection, the interruption in their calving cycle has a ripple effect on the bottom line. Since one calf is worth $500 or more when it hits the ground and about $1,000 when sold, profits are heavily pinched.
Losses from BVD also mount quickly. This infectious agent can cause an increase in average open days in a herd and force early culling of cows, Ensley says. There are higher numbers of stillbirths, or calves dying shortly after birth. Surviving calves are often weaned lighter and likely will never reach their full performance potential.
“If BVD infects a pregnant cow, the calf can become persistently-infected (PI),” Ensley says. “A PI calf can shed BVD Types 1 and 2 viruses to other cattle in the herd, but we eliminate the PI calf with a MLV. And we recommend that if you’re buying replacements, use PI testing to make sure you’re not exposing your herd to PI animals.”
Properly used, the MLV also protects against Lepto hardjo-bovis, a major cause of reproductive failure in cattle, birth of weak calves and other problems. The vaccine prevents shedding of the disease bacteria through urine, which may occur for an extended length of time.¹
Ensley notes that research has shown that EXPRESS FP vaccine is safe in pregnant cows and calves nursing pregnant cows, provided the cows had received the vaccine in the last 12 months, according to label directions. Clinical studies show that vaccination with EXPRESS FP vaccines helps prevent abortion in heifers challenged with IBR 12 months post vaccination (see website listed below).
“Again, the MLV is safe if used according to label instructions,” Ensley says. “That’s the biggest factor.”
If there are situations in which an MLV cannot be used in a herd, then a KV is needed. “BIVI is unique, in that we have both the MLV and a KV, Triangle®,” Ensley says. “If you’re in a position where you can’t vaccinate at pre-breeding or at preg-check time, or you purchased animals with no prior health history, use the KV.
“No matter what, it’s important that you vaccinate cattle to provide them the utmost protection against IBR, BVD and Lepto hardjo-bovis. You’ll raise healthier, heavier calves. You’re going to make more money. That’s why we’re in the cattle business,” Ensley says.
¹-Boehringer Ingelheim Vetmedica, Inc. Protection for Lepto borgpetersenii serovar hardjo using EXPRESS FP. Technical Bulletin No. TB10-138, St. Joseph, MO
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