Without detection and proper treatment, Lepto hardjo-bovis (LHB) — a primary cause of bovine leptospirosis in U.S. cow herds and a leading contributor to reproductive loss — could be lurking in cattle and robbing the herd’s profitability. “Leptospirosis is most often seen causing late term abortions, but it also is a cause of stillbirths, weak born calves, and occasionally infertility and early embryonic death,” said Dr. Craig A. Payne, director of the MU College of Veterinary Medicine’s Department of Veterinary Extension and Continuing Education.
“Leptospira strains colonize the kidney and reproductive tracts of cattle and the organism is shed in the urine,” said Payne. “Susceptible animals that come into contact with infected urine are at risk of becoming infected themselves. When conditions are right, this organism may survive in the environment up to six months.”
According to Payne, diagnosing leptospirosis caused by LHB is not easy and it is expensive. “It’s a combination of trying to detect the organism in a urine sample coupled with looking at antibody titers in a blood sample,” said Payne.
Despite the difficulty, the importance of detection remains high due to the potential financial losses if the organism remains in the herd. “When L. hardjo-bovis infects one cow, it affects the whole herd. Because of the organism’s presence in urine, all animals are considered exposed. In infected herds, 30 to 40 percent of infected cattle may be shedding the organism at any one time,” said Dave Sparks, DVM, OSU Area Extension Food Animal and Health Specialist.
“Because LHB can be host-adapted, it may not cause acute problems like other strains of Lepto,” Sparks said. “Being host-adapted, makes it more difficult to detect in serum and urine samples. It can hide more easily in herds and not be suspected until you start seeing increased infertility, weak calves, decreased milk production or still birth. Preventative vaccines help producers avoid the disease and the expensive diagnostic testing required to confirm LHB.”
“In the U.S., the primary means of controlling leptospirosis is through the use of a 5-way vaccine,” said Payne. However, Payne explained that these “5-way” vaccines may not provide adequate protection. The reason being that “these vaccines do not contain Leptospira borgpetersenii serovar Hardjo type Hardjo-bovis, which is the only type of serovar Hardjo isolated from cattle in the U.S. To address this, some companies are providing vaccines which contain Hardjo-bovis.”
Sparks suggested the best way to enhance the efficiency and effectiveness of vaccines is to work closely with a veterinarian and maintain annual boosters, being careful to abide by label requirements for administration and handling. “To maximize the immune response of adult cows to the 5-way vaccine, it should be given about six to eight weeks before breeding season starts,” said Sparks.
“Cattle are susceptible to LHB at all ages, so early vaccination is imperative,” said Tim O’Neill, DVM, owner of Country Veterinary Services, Farmington, Ark. “If you can prevent an episode versus having to administer high-dollar antibiotics, it makes good sense.”
“Heifers must be vaccinated and boostered against the five strains of Lepto after they are at least five months of age,” said Eldon Cole, MU Extension Livestock Specialist. “Another 5-way Lepto vaccine is required at the first pregnancy check which will be before they are 90 days along in the pregnancy. Vaccination times are critical to give the greatest protection during the last three months of gestation,” said Cole.
“Even when it costs extra, and even when cattle prices have dropped, producers will be ahead of the game if they get on a proper herd health program,” said O’Neill.
“Controlling LHB requires a combination of antibiotics, vaccination and isolation (of infected animals). Start by eliminating carriers through antibiotic treatment, combined with a vaccination program to prevent new infections. When selecting a lepto vaccine, make sure that it contains an L. hardjo-bovis serovar,” said O’Neill.
“Antibiotics alone can still leave cattle susceptible to LHB reinfection. An antibiotic regimen coupled with an effective vaccination program is the best way to prevent cattle reinfection,” said Sparks.
