We are currently in the middle of unprecedented times with regard to human health. We must all adhere to guidelines from the HSE with regard to personal hygiene and social distancing to slow the spread of COVID-19. Despite the global pandemic facing humans, animal health remains a priority for farmers.
Grazing systems have been largely disrupted by the weather this spring. Calving is drawing to a close and turnout to grass is beginning to happen in parts of the country where ground conditions allow. As calving comes to an end, focus turns to breeding management. Selecting the correct genetics is vital to the performance of the herd and in order to fully achieve the genetic potential of the herd, correct decisions with regard management, nutrition and animal health must occur. For the purpose of this article, we will focus on Leptospirosis, a disease that cattle are exposed to while at pasture and can effect their reproducitve performance.
In the pre-recorded video below, Cara Sheridan (Technical Advisor – MSD Animal Health) outlines the effect of Leptospirosis disease on cattle performance and mechanisms by which Leptospirosis can be controlled.
Leptospirosis is one of the most common causes of abortion in cattle in Ireland. It is an endemic disease, meaning that the majority of herds test positive for it.
Leptospirosis is a zoonotic disease meaning it can cause disease in humans. Leptospirosis can be acquired from contact with urine, afterbirth or aborted foetus of an infected animal. Esentially, all those working with stock are potentially at risk. Clinical signs of the disease in humans are flu-like, with headaches and fever, occasionally progressing to meningitis.
- There are two serovars of Leptospirosis commonly found in cattle in Ireland;
Leptospira interrogans hardjo and Leptospira borgpetersenii hardjo
Leptospirosis circulates in a herd by direct transmission from infected animals (new infections or carrier animals) or by indirect transmission through urine, birth fluids, milk, contaminated water or other species e.g. sheep. Leptospirosis is very difficult to eradicate as some cows can become carriers. Leptospires can also survive for up to six weeks in wet soil and stagnant water or slow moving streams.Clinical Signs of Leptospirosis
Early signs are usually mild and transient and therefore may go unnoticed.
The most common clinical signs include;
- Milk drop – A sudden decrease in milk yield
- Abortions – Usually occur 6-12 weeks after the initial infection.
Abortion rates may be up to 30% in a herd infected for the first time.
- Infertility – Low pregnancy rates and therefore increased culling due to low fertility
- Weak calves – Infection in late pregnancy can result in the birth of weak calves that die within a few hours of birth
Diagnosis of Leptospirosis
- Blood sampling and looking for high antibodies level in affected animals (which can prove difficult as often the infection were present 6-12 weeks before clinical signs become apparent e.g. low pregnancy rates picked up at scanning)
- Culture of urine samples
- Leptospiral abortion diagnosis is best based on finding bacteria in the foetus
Speak to your vet about investigating Leptospirosis in your herd.
Control of Leptospirosis
- Isolation of the sick cow and aborting cow
- Biosecurity – Avoid the introduction of infected animals
- Quarantine until test negative
- Double fencing at perimeters
- Vaccination – The only practical way of controlling Leptospirosis
Timing of Vaccination
It is essential to vaccinate heifers before their first pregnancy. The primary vaccination course consists of 2 injections 4-6 weeks apart and thereafter an annual booster before turnout and at least 2 weeks before breeding. It is a 2ml dose, given under the skin to all cattle >1 month of age. The correct use and timing of vaccination are vital to their success, always read the manufacturers recommendations.
Why vaccinate with Leptavoid-H?
- Leptavoid-H is the only vaccine licensed to protect against both strains of Leptospira hardjo
- Leptavoid-H is the only vaccine that is licensed to improve conception rates where Leptospirosis has been diagnosed as a cause of infertility
- Leptavoid-H can be used on the same day as Bovilis BVD (to cattle >8 months of age)