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Numerous young calves have been dying in North West since early in December without having showed any significant disease symptoms beforehand. Lichtenburg, Ventersdorp, Swartruggens, and Coligny are among the areas where cases have been reported.
In some instances, autopsy reports have confirmed that some of the deaths could be linked to foot-and-mouth disease (FMD) which damaged the calves’ heart muscle.
Kobus Bester, a stud breeder from Ventersdorp and chairperson of the South African Stud Breeders Federation, as well as a director of the Livestock Registration Federation (LRF) says that many animals, especially calves aged three months or younger, have already died in the Ventersdorp district. While calves appear to be healthy and in good condition, their hearts suddenly fail, leading to sudden deaths. At this stage, the cause of death is still under investigation.
Social media speculation denied
Meanwhile, social media has been abuzz with claims that these deaths are the result of FMD vaccinations in adult animals. Dr Danie Odendaal, director of the Veterinary Network (V-Net), and Dr Shaun Morris, director of Octavoscene, have dismissed these social media claims as pure nonsense. Both veterinarians are members of the Ministerial FMD Task Team. They disregard the rumours because government has not yet initiated vaccination programmes against the state-controlled disease in these areas.
Bester says FMD has now reached its highest level in many years, as indicated by the number of outbreaks, the number of animals affected, and the surface area on which outbreaks are occurring. The disease is affecting animals to such extent that deaths among young calves, cows, and especially bulls, are now common. As a result, producers are suffering significant production losses. Infected bulls become infertile, which in itself has a significant negative impact on production.
While adult animals and even older calves have only exhibited minor lesions in their mouths, young calves have suddenly started succumbing to heart failure.
Vaccine delays
Bester says although the Ministerial FMD Task Team has the necessary expertise and has made the correct recommendations, industry has yet to see any tangible implementation of these recommendations. There is an urgent need for a high-quality, long-term DIVA vaccine (a vaccine that allows for immunological differentiation between infected and vaccinated animals). Such a vaccine is expected to bring the problem under control, especially if administered preventatively.
It is therefore crucial that viral material is sent to the Pirbright Institute in Britain as soon as possible. This will ensure that an analysis of South African FMD field strains can be carried out with certainty, enabling the development of effective vaccines against local strains.
Dr Odendaal says import permits for FMD vaccines are still difficult to obtain. Bureaucratic processes are the main reason for this delay. Vaccines are expected to be imported by the end of the month. He believes the slow import process is the main reason why the country is struggling to control the disease effectively.
“This outbreak began four and a half years ago, and only now that the disease has increased to such an extent that it can no longer be stopped, there is light at the end of the tunnel. We will no longer be able to stop the disease; all we can do now is try to reduce production losses on individual farms through vaccination.”
New FMD syndrome
Dr Odendaal has spoken with several veterinarians in the areas where calves have died. They confirmed that adult animals and even older calves had only minor lesions in their mouths, but that young calves nevertheless started dying from heart failure. Post-mortem examinations found that the virus had affected the lungs and heart muscles of the young calves, without the typical FMD symptoms, except for a few lesions in the mouth.
He describes this as a new FMD syndrome in the country. “The cases initially occurred in herds that had never been vaccinated against FMD. These herds show no association with a syndrome of calf deaths due to vaccination. We have sent samples to Onderstepoort’s laboratory for confirmation.”
FMD is everywhere
Dr Morris says FMD should now be regarded as endemic throughout South Africa. However, it is nonsense to claim that there are general pathogens on the veld that can infect calves with FMD. “The infection in calves are transferred from the older animals, but because it affects the young calf’s heart, sudden deaths can occur.”
These incidents have also occurred in dairies and feedlots where many animals are confined to a small area. However, these are the first cases in South Africa where veld-reared beef cattle have become so infected that young calves are dying in great numbers.
Dr Morris explains that the disease has already produced several strains and syndromes, making it difficult to control. However, he expects breakthroughs using vaccines that can be imported by the end of the month, which should bring the disease under control.
Contributing and supporting factors
Dr Paul Reynolds, a veterinarian at the Warden and Vrede animal hospitals, says FMD spreads faster in certain areas than others, yet the progression of the disease within a herd is relatively similar. He points to three important aspects to pay attention to:
- The age of the calves.
- The immunity of the cows, especially heifers.
- The animals’ mineral status and condition.
According to him, deaths of between 5 and 20% have been recorded among calves younger than three months of age. Stress and handling are the biggest contributing factors. Cows whose vaccinations are up to date do not need to fight off other diseases at the same time. The calves of these cows therefore possess good immunity, for example, against pneumonia, which can flare up under normal circumstances and stressful weather conditions.
He believes that adequate minerals and good condition are two factors that help livestock to better combat any disease, including FMD. — Koos du Pisanie and Christal-Lize Muller, Plaas Media
