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Respiratory disease reduces daily gain, milk production

Martha Blum

NEW PRAGUE, Minn. — Respiratory disease is common in dairy heifers. However, cost estimates vary considerably.

“Some of the reasons they vary are due to the severity of the disease, how it is managed and protocols to treat or prevent vary considerably from operation to operation,” said Kevin Dhuyvetter, Elanco cattle technical consultant. “Probably the biggest reason costs vary is the method of analysis.”

In one study, Dhuyvetter said, the incidence rate of bovine respiratory disease in dairy heifers ranged from 21% to 90% in four herds located in New York and Georgia with the average at 61%. “In another study, the incidence was 25% birth through 90 days, 7.6% birth to 112 days and 6.2% birth to 120 days,” Dhuyvetter said during a webinar organized by the Dairy Calf and Heifer Association.

“What is being reported is all over the board and in many cases the incident cases that are reported are probably a little low due to not recording or detecting as accurately as we would like.”

The consequences of a dairy heifer with BRD are variable.

“You can see a decrease in feed intake, calves that are lethargic and not eating, a decrease in the rate of gain, costs to treat and some calves are going to die,” Dhuyvetter said.

“An animal that is treated has a higher risk of being culled, there’s a potential for a delay in first service, likely a delay in first calving and there can be a carryover effect in first lactation of lower milk production.”

Dhuyvetter noted a study that showed the effects of BRD on the daily gain of heifers. “During the first 30 days calves that had BRD gained 0.15 pounds less compared to calves without BRD,” he said. “In another study, calves with BRD from 60 to 120 days gained 0.37 pounds less, next three to six months they gained 0.15 pounds less and from six to nine months, 0.10 pounds less.”

Calves with BRD, Dhuyvetter said, calve considerably older than non-affected herd mates.

“This study shows 27% of heifers failed to calve by 25 months versus healthy calves,” Dhuyvetter said.

“If BRD is present, the calves are growing slower, and if we’re starting our reproduction program based on a minimum size, the heifers will be inseminated later and calve later,” he said.

Unique Vaccine “The Nuplura PH vaccine is really unique because it is the first ever cattle vaccine that uses recombinant technology to reproduce leukotoxin in fermentation vats,” said Mark Armfelt, dairy technical consultant for Elanco. “That allows us to get a consistent level of leuktoxin.”

In a study of feedlot cattle, 65% of the cattle did not receive a treatment for bovine respiratory disease and the lungs of the cattle were examined when they went to harvest.

“Although two-thirds of the animals were never pulled for respiratory disease, they had lung lesions,” Armfelt said. “Those animals had a reduced average daily gain of 0.17 pounds per day.”

This means, Armfelt said, that cattlemen have to do all they can to prevent BRD and minimize the consequences of the disease because they don’t find every animal that is sick.

“Prevention is more effective than treatment and an effective vaccination can be a part of minimizing calf pneumonia, death loss, the reduction of average daily gain and loss of milk in first lactation heifers,” Armfelt said. “But it’s not the only thing because you can’t vaccinate your way out of BRD, but vaccination is a part of it.”

When a vaccination is given to a cow, Armfelt said, it results in milk loss.

“The animal needs some energy to mount an immune response to the vaccine, so the immune system uses energy to make the antibodies that will prevent her from that disease down the road, so there is a little less energy available to go to milk production,” Armfelt said.

“The endotoxin load in the vaccine will make the animal a little sick, which lowers her average daily intake and decreases the amount of milk she will make,” he said. “Any time we handle, sort and restrain animals will have an impact on milk loss.”

Therefore, Armfelt said, a study was conducted to evaluate the impact of vaccinating cattle.

A group of 972 cows were divided into three groups for the study — 315 cows received Nuplura, 342 were treated with saline and 315 cows did not receive a shot.

The baseline for the average milk production was measured seven days prior to the treatment and the researchers evaluated milk production one, two and three days after vaccinating.

“By day four, milk production was back to normal,” Armfelt said.

“The saline cattle lost an average of 0.54 pounds of milk per day, which was not statistically different than the cows that got nothing,” he said. “The cows that got Nuplura lost an average of 1.54 pounds of milk per day, which was not statistically different than the cows that got saline.”

In addition to the cost of the vaccine, dairymen should also include the milk loss and cost to administer the vaccine.

“The cost of Nuplura is $2.49 per dose plus 60 cents for three days of lost milk that totals $3.09 to vaccinate each animal,” Armfelt said. “So, as we vaccinate cows, we need to consider the impact on milk loss.”



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