31st August 2018
Over the past twelve months we have investigated a number of herds with sub-optimal conception rates and have noticed an alarming increase in the number of vibrio cases detected.
Vibrio (also known as Campylobacteriosis) is a sexually transmitted disease caused by the organism Campylobacter fetus venerealis. The bacteria is carried by bulls within their sheath and transmitted to cows at mating, generally causing significantly reduced conception rates and occasionally abortions. Once the vibrio bacteria is passed from the bull to the cow it causes an inflammatory reaction within the uterine lining. This will then likely prevent an embryo from attaching to the uterine wall and will cause early embryonic death. The bacteria can be spread from bull to bull if they both serve the same cow.
The cows will eventually mount an immune response and clear the infection within 2-3 further oestrus cycles, however in most instances this will be too late to then get pregnant again within a 9-12 week joining period. Unfortunately this immunity is only relatively short lived (months rather than years) and therefore most cows will be susceptible again at each joining.
As the most common outcome is early embryonic loss you are unlikely to observe signs of an abortion. The most common sign will be a delayed return to heat i.e. the heifer is mated and conceives before undergoing early embryonic loss around day 30-40. Hence she will return to oestrus after 40-50 days rather than the usual 21 days.
We may not get an indication that there has been a problem until pregnancy testing where we may see a much lower than normal conception rate or a trend towards more pregnancies in the latter half of the joining period.
Vibriosis will have more significant deleterious effects where a reduced mating period is present because the females will not have long enough time to get back into calf if infected. Hence the effects on a six week heifer joining can be quite spectacular.
With Vibriosis prevention is the best method of attack. This is achieved through annual vaccination of all bulls in the herd as the bulls are the sole carriers of the disease. Initially 2 doses of 5ml are required 4-6 weeks apart with an annual 5ml booster for the remainder of their working life. Most bulls purchased from recognised studs will have received two vaccinations however sometimes they may have received only one or even no vaccinations so it is best to read the catalogue or ask the vendor.
On properties with confirmed cases of Vibrio we will need to undergo an initial eradication phase before reverting back to a prevention phase. Initially it may be best to cull some of the oldest bulls within the herd and replace them with younger bulls as they are more likely to act as carriers. The remaining bulls should all then be given 2 doses of vaccine 4-6 weeks apart as this be enough to treat most carrier bulls. Additionally it is recommended that a female vaccination program is undertaken where heifers and first calvers are vaccinated for 2-3 years until the disease is under control.
If you have any questions about Vibrio feel free to ask us about control and diagnosis options and if not remember to get in and give existing bulls their annual vibrio vaccination shortly because joining is just around the corner.