Leptospirosis Vaccination: Overcoming milk drop in Co. Kilkenny

Leptospirosis is one of the most common causes of abortion in dairy and beef herds in Ireland and according to Richard Ryan from Ormonde Veterinary Hospital, now is the ideal time to take control of the disease through an effective vaccination programme.

“With the breeding season just around the corner, we have to watch out for key diseases that are going to impact herd fertility. Leptospirosis can be detrimental to fertility as it can contribute to decreased conception rates as well as abortions weeks after the initial infection.”

Patrick Darmody explains how he protects his herd against leptospirosis while local vet Richard Ryan gives some pre-breeding advice

One farmer who has seen the benefits of implementing a vaccination programme against Leptospirosis is Kilkenny farmer, Patrick Darmondy. A fourth-generation farmer, Patrick runs a dairy and beef enterprise alongside his mother and wife.

Achieving optimum herd health, fertility and survival are key priorities for Patrick. His herd is made up of 50% Holstein Friesian, British Friesian crosses to promote hybrid vigour and 100% AI is carried out on the farm in order to maintain a closed herd policy. 

Clinical signs of Leptospirosis

The first step in protecting against any animal disease is identifying the cause of the problem. 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.

According to Richard, Leptospirosis can affect cows in a variety of ways. “Similar to what was happening on Patrick’s farm, your herd may experience milk drop syndrome. However, one of the biggest problems we see on farm is decreased conception rates and also abortions, which can typically occur 6-12 weeks after the initial infection.”

Diagnosing Leptospirosis

Diagnosis of the disease is based on blood sampling and looking for high antibody levels in affected animals, however this can prove difficult. Often the infection is present 6-to-12 weeks before clinical signs become apparent (e.g. low pregnancy rates picked up at scanning).

It can also be based on the culturing of urine samples. In addition, leptospiral abortion diagnosis is best based on the identification of bacteria in the foetus.

Failure to control the disease can not only have a detrimental effect on the health and production of the herd, but it can affect people too as it is a zoonotic disease – it can cause disease in humans. Common forms of transmission include contact with urine, afterbirth or the aborted foetus of an infected animal.

Vaccination is the number one control strategy

Vaccination is the most reliable way of protecting your herd from Leptospirosis and according to Richard, “We vaccinate to protect your herd but also to help to protect you.”

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 2 ml dose, given under the skin to all cattle greater than one month of age. The correct use and timing of vaccination are vital to their success and always read the manufacturers recommendations.

Leptavoid-H
Leptavoid-H is the only vaccine that provides protection against two strains of leptospirosis

Why vaccinate with Bovilis Leptavoid-H?

Vaccination is a crucial part in controlling this highly infectious disease, however to provide full protection, it is vital to vaccinate against both strains of bacteria that cause the disease.

Bovilis Leptavoid-H is unique in the fact that it is the only vaccine licensed to protect against both strains of Leptospira hardjo. It is also the only vaccine that is licensed to improve conception rates where Leptospirosis has been diagnosed as a cause of infertility. Another additional benefit of Bovilis Leptavoid-H is that it can be used on the same day as Bovilis BVD (to cattle greater than eight months of age).

According to Patrick, “Since vaccinating with Bovilis Leptavoid-H, there has been no going back. I know the vaccine works; fertility has improved, we have had no milk drops and with Leptospirosis being a zoonotic disease, there is reduced risk to anyone working here on the farm.

“We also find it extremely convenient that we can vaccinate with Bovilis Leptavoid-H at the same time as vaccinating against BVD using Bovilis BVD.”

BVD eradication – Update and control measures

The incidence of BVD among Irish herds has declined dramatically since the introduction of the eradication programme in 2013. In 2013, there was 16,194 cattle identified as positive for BVD. In 2020, there was 804 cattle identified positive for BVD. As of week 9 2021 there has been 159 animals identified as positive for BVD in comparison to 168 for the same period in 2020. While these results indicate great progress has been achieved in eradicating this disease, these figures show that the virus still circulates in our national herd. To ensure this disease is eradicated we must continue our approach, as outlined below, at farm level since the introduction of the eradication programme.

How does BVD spread?

This mainly occurs by nose-to-nose contact between infected cattle within the herd. Introduction of infected animals (either transiently or persistently) to the herd provides the greatest risk. Contact with infected animals from neighbouring farms, at marts or shows and during transport facilitates spread of disease. Animals can be infected by exposure to contaminated equipment, other species including sheep or by visitors to the farm.

What is a transiently infected (TI) animal?

Acute or transient infection occurs when an animal becomes infected for the first time at any point in its life after it is born. The animal may scour and occasionally it can result in death of the affected individual but often this infection is not associated with any obvious signs. When animals are transiently infected with BVD their immune system recognises the disease and responds by producing antibodies to protect against the effects of BVD.
Transiently infected (TI) animals test virus positive at the time of infection but become virus negative within 3 weeks after infection. Once TI animals become clear of BVD virus they are no longer a threat to the rest of the herd. The majority of PI animals are born to cows which were transiently infected in the first 4 months of pregnancy.

Why do I need to vaccinate if I am testing all calves and removing PI’s?

Removal of PI animals will decrease the amount of virus circulating within the herd. However, if cows are not protected during pregnancy, transient infection during the first 4 months of pregnancy can result in the birth of future PI calves. The most effective approach to BVD control within the herd is to test and eradicate PI carriers, vaccinate to protect pregnant cows and be vigilant regarding biosecurity. On-going monitoring to ensure the herd control measures are working, form the last critical aspect of a comprehensive control plan.

Bovilis BVD Vaccination Protocol


8 CRITICAL POINTS RELATING TO BVD ERADICATION

  1. Tissue tag testing remains compulsory in 2020.
  2. Take tissue tag samples from all calves as soon as possible after birth.
  3. Submit samples to a designated laboratory.
  4. Tissue tag and test all calves born including still births.
  5. Carry out all necessary follow up testing once a PI is identified e.g. test dam of PI. If the dam is also positive all her other offspring must be tested. Where a decision is taken, based on veterinary advice, to re-test the calf, this must be done by means of a blood sample only (this also applies to testing of dams). DAFM will meet the costs of the visit by the herd’s veterinary practitioner and of testing the calf (and dam
    if sampled at the same time).
  6. A PI animal should not be sold but should be isolated and culled at the earliest opportunity. DAFM will automatically restrict movements into and out of herds that retain PI animals for more than 21 days after the date of the initial test (in the absence of a recorded date of death on AIM). DAFM supports for removal of PI calves remain at the following rates:
    BEEF HERDS:
    i. €220 for beef breed animals removed with a registered date of death on AIM within 10 days of the initial test, reducing to €30
    if removed between 11 and 21 days after the initial test.
    DAIRY HERDS:
    i. Dairy heifers and dairy cross calves: €160 if removed within 10 days of the initial test, reducing to €30 if removed between 11
    and 21 days after the initial test.
    ii. €30 for removal of bull calves within 14 days of the initial test.
    It is anticipated that from 1st April 2020, there will be a legal requirement to test pre-2013 born animals.
  7. Vaccinate all breeding animals before service each year to protect against infection.
  8. Maintain high level biosecurity and continue monitoring to ensure freedom from disease.

To find out more about BVD vaccination, please contact your veterinary practice.

Use Medicines Responsibly
Bovilis® BVD Suspension for injection for cattle vaccine contains inactivated antigen of cytopathogenic
BVD virus strain C-86.
Legal categories: ROI: POM (E) . NI: POM-V . Withdrawal period: zero days.
For further information please contact your vetinary practioner or MSD Animal Health Technical Team,
MSD Animal Health, Red Oak North, South County Business Park, Leopardstown, Dublin 18, Ireland.
Tel: +353(1) 2970220. E-Mail: vet-support.ie@merck.com
Web: www.msd-animal-health.ie