The Aberdeen Angus Cattle Society are committed to improving the health of the national herd, with a working group of vets and breeders (a sub group of Council) continually looking at ways to help advance Herd Health and ensure that all members within the Society are supported and assisted as required. Herd Health is the most important issue affecting your enterprise, be it if you are starting up or long established. Never assume, always ask questions, know your own Herd Health status and protect your herd with good biosecurity. Join one of the Herd Health scheme providers, who will lead you to an accredited status or control of the diseases. CHeCS providers can be found at: https://www.checs.co.uk/about-us/cattle-health-licensed-schemes/. They will help your vet work to progress and successfully manage your herd health
There are a large number of cattle diseases that can be passed on by poor farm biosecurity, including buying in infected cattle. The costs can be considerable, for example, it is known that in just 10 years, uncontrolled BVD in a 100-cow herd can cost at least £45,000, and for Johne’s Disease, more than £20,000. Defra estimates that BVD costs the cattle sector between £25-61 million per year whilst Johne’s is estimated at £13 million per year. These are considerable and often underestimated costs.
By clicking on the links below, you can find key information around some of the most common diseases affecting Herd Health within the cattle industry.
BVD is a viral disease of cattle and other ruminants that is caused by the bovine viral diarrhoea virus (BVDV). BVD is transmitted in a number of ways, either through a congenital infection of the foetus or after birth. Congenital infections may cause resorption, abortion, stillbirth, or live-birth. Congenitally infected foetuses that survive in utero infection (i.e., the live-births) may be born as BVDV-infected calves. The BVDV infection in these calves will persist during the entire life of the calf, and they will shed BVDV continuously in the farm environment.
In adults, clinical signs are highly variable. Signs of acute infection include fever, lethargy, loss of appetite, ocular discharge, nasal discharge, oral lesions, diarrhoea and decreasing milk production. Chronic infection may lead to signs of mucosal disease. In calves, the most commonly recognised birth defect is cerebellar hypoplasia. The signs of this include Ataxia/lack of voluntary coordination of muscle movements, tremors, wide stance, stumbling or failure to nurse. In severe cases, the calf may die. Transient infections include diarrhoea, calf pneumonia, decreased milk production, reproductive disorders, increased occurrence of other diseases, and death. The losses from foetal infection include abortions; congenital defects; weak and abnormally small calves; unthrifty, persistently infected (PI) animals; and death among PI animals.
Treatment of BVD is limited primarily to supportive therapy. Once identified, infected animals should be culled. A strategic vaccination programme is the best way to avoid the difficulties of the disease on farm and eliminate reproductive loss and losses due to the subsequent effect on herd health. Good measures would include the removal of PI cattle from the herd, alongside a vaccination programme and enhanced biosecurity for the herd. Available BVD vaccines are; Bovela (live) Bovilis BVD (inactivated). These are available through your veterinary surgeon and should be used under their advice only, with the complete knowledge of the ongoing health status monitoring and disease control.
M. paratuberculosis grows and multiplies inside the cells of an animal’s immune system and are excreted in the faeces, and to a lesser extent in milk and saliva. When the microbe is excreted, it can contaminate the soil or water. Outside the host animal, the organism multiplies poorly, if at all, but it can survive over a year in the environment because of its resistance to heat, cold, and drying. The primary cause of the spread of Johne‘s Disease is contact with the faeces or saliva of an infected animal. Prenatal exposure may be a source of infection for calves. Becoming infected before birth is possible for a foetus if its mother is in the late stages of Johne’s Disease. Another source of infection is milk from infected dams.
Because of the slow, progressive nature of the infection, signs of Johne’s Disease may not show up until years after initial infection. When they finally do occur, the signs are long-lasting diarrhoea and weight loss despite good appetite. Once clinical signs appear the animal will not recover and will continue to deteriorate.
There is no treatment for Johne’s disease, prevention is the most cost-effective way to manage the disease. It is far less expensive to block introducing Johne’s Disease into a herd/flock than it is to control or eradicate the infection once it creeps in and invisibly starts to spread. Testing ill-looking animals can confirm whether Johne’s Disease is present. If it is, the most economical route to control it would be to cull infected animals. If not, the animal must be managed to ensure no young animals are exposed to their milk or manure. Newborn animals must be protected from infection by being born and raised in a clean environment and fed milk and water free of M. paratuberculosis contamination. The primary source of contamination is manure from an infected adult animal.
Producers are advised to purchase animals from a source herd free of Johne’s Disease. Second best is to work with a producer who knows the level of Johne’s Disease in his or her herd, follows good infection control practices, and then purchase test-negative animals from test-negative dams. Johne’s Disease is a herd problem, and knowing the test-status of numerous adults in the source herd will give you a much better sense of the risk of purchasing an infected animal than the one test result you might get on the one animal you wish to buy.
A vaccine for Johnes was only ever produced by DEFRA, under strict license. It is very rarely used these days, only under exceptional circumstances where the herd level of infection is so great that this is the only economic option available.
After the first infection, the virus is never fully removed. It stays behind in nerve cells in the brain as a life-long hidden infection. However, at times of stress the virus can begin to multiply again and may be re-excreted, generally from the nose and the eyes; an animal which has been infected can never be considered safe. Purchase of infected animals is the main source of new infections. Diseases caused by the virus can be serious; therefore, it is a barrier to international trade. Cattle with BoHV-1antibody cannot be exported to BoHV-1-free countries. Neither can they be accepted into an artificial insemination (AI) centre.
Symptoms include fever, coughing, depression, loss of appetite, mucosla lesions, nasal discharge, conjunctivitis, drop in milk production, infertility and abortion. There is no direct treatment for viral diseases. Infected animals should be isolated from the rest of the herd and treated with anti-inflammatory drugs and antibiotics for secondary infections if necessary. Carrier cattle should be identified and removed from the herd.
There are a number of IBR vaccines available for use on the market today from a number of manufactures:
- Zoetis Brands include – Rispoval IBR marker live, Rispoval IBR marker inactivated, Tracherine non-marker [live] and Rispoval 4 (non-marker), which has an inactivated IBR component
- MSD Brands include – Bovilis IBR marker live and Bovilis IBR marker inactivated
- Hipra Brands include – Hiprabovis IBR marker live (double gene deleted)
Zoetis is the only company which make non-marker IBR vaccines. These are not suitable for pedigree herds, as serological testing doesn’t allow us to distinguish between natural infection with wild-type IBR versus just having been vaccinated. Pedigree herds wishing to monitor their herds regarding IBR infection, and also present cattle for certain European country exports, would be best advised to vaccinate with marker vaccines to allow this. Tracherine and R4 are generally only used in commercial cattle set-ups where the aim is not to do any testing or exports etc, but just to protect the calves against IBR as part of their pneumonia prevention strategies.
Remember, AI studs and some EU countries will not allow cattle to be vaccinated against IBR at all, which is an important point for some pedigree herds of course. It is important to remember that, as always, appropriate biosecurity will also reduce risk on farm.
An animal may be infected by serovars maintained by its own species (maintenance host infection or host-adapted infection) or serovars maintained by other species (incidental infection or nonhost-adapted infection). Leptospirosis is transmitted either directly between animals or indirectly through the environment. The clinical signs of Lepto depend on the herd’s degree of resistance or immunity, the infecting serovar, and the age of the animal infected.
Leptospira hardjo-bovis is the only host-adapted Lepto serovar in cattle and can infect animals at any age, including young calves. Infections with hardjo-bovis can persist in the reproductive tract. The infertility that can result from persistent reproductive tract infections is perhaps the most economically damaging aspect of Leptospirosis. Low antibody titers are typically associated with hardjo-bovis infections, making detection and diagnosis difficult.
Leptospira pomona, icterohaemorrhagiae, canicola, and grippotyphosa. Because cattle are incidental hosts for these Lepto serovars, the signs are typically very different than infection with hardjo-bovis. When leptospirosis associated with nonhost-adapted Lepto serovars occurs in calves, the result is high fever, anemia, red urine, jaundice, and sometimes death in three to five days.
In older cattle, the initial symptoms such as fever and lethargy are often milder and usually go unnoticed. In addition, older animals usually do not die from leptospirosis. Lactating cows produce less milk, and, for a week or more, the milk they produce is thick and yellow. Leptospirosis with nonhost-adapted Lepto serovars also affects pregnant cows causing embryonic death, abortions, stillbirths, retained placenta, and the birth of weak calves. Abortions usually occur three to ten weeks after infection.
Antibiotic therapy should be prescribed for animals with leptospirosis. Antibiotics can also eliminate persistent infections. Infected animals should be segregated from others to avoid transmission of the disease. Vaccination is relied on to increase resistance to infection. Lepto vaccines are;
- Spirovac (inactivated)
- Leptavoid-H (inactivated)
These are very similar vaccines, but Leptavoid-H data sheet claims to protect against two variants of Lepto in cattle, versus Spirovac which only claims to do one. There is strong evidence that Spirovac gives cross protection against the other Lepto strains so they probably both do the same job. Management methods to reduce transmission include rat control, fencing cattle from potentially contaminated streams and ponds, separating cattle from pigs and wildlife, selecting replacement stock from herds that are sero negative for leptospirosis and chemoprophylaxis and vaccination of replacement stock. In some cases, streptomycin is added as a precautionary measure to semen from bulls held at artificial insemination centres.
There has been a recent increase in awareness of Neospora in the UK, and this is largely because of the negative effects the disease can have on cattle production, with abortions in the later stages of pregnancy and stillbirths being the primary effect when cattle become infected. This inevitably leads to reduction in margins with stretched calving intervals, decreased productivity, and increased culling within the herd.
While infected dairy cows are more likely to abort each pregnancy after initial infection, the beef breeds of cattle tend to be more resistant to repeated abortion and following initial infection may abort once and then maintain a normal pregnancy thereafter. However, an infected cow will pass the disease on to their calves in excess of 90% of the time. This means that apparently healthy heifers born to Neospora positive cows can harbour the disease within a herd. The passing of disease from cow to calf is the primary route of Neospora infection.
The Neospora parasite is also shed in aborted material from infected cows (afterbirth or tissue of aborted calf) which, if eaten by a dog, can allow the Neospora to multiply. Infected dogs will pass on the disease to all subsequent litters of puppies. The parasite can multiply within the dog and is shed in the dog faeces. If cattle come into contact with the faeces of an infected dog via soiling on pasture, watercourses or feed stores or clamps they can then be infected. Neospora infection from dog faeces is generally a minor route of infection. Due to the necessity for a dog to have come into contact with aborted material from an infected cow it is very unlikely that town dogs walking on public footpaths play any real part in the disease spread. Indeed, most research would point to farm dogs being the culprits for spreading the disease via this route. It is therefore important to prevent farm dogs from eating any aborted material and ensure that they do not muck near feed stores or grazing pasture.
Once a cow is infected there is no treatment or cure for the disease, the risk of abortion or passing on the disease to offspring is so high that in pedigree herds the best option is to remove the animal from the herd. If the genetic value is high enough, embryos from the infected cows can be trypsin washed prior to use, which will reduce risk of the disease passing on if implanted into clean recipients.
Testing for Neospora is carried out at most of the commercial laboratories and the major health scheme providers now offer the option to test and become accredited free. Testing for the disease should be carried out on all females in a specific window between 12 and 4 weeks prior to calving, as the disease is more likely to show at this point in pregnancy. Two clear tests 12 months apart will allow the herd to become accredited free. When buying in breeding cattle, a blood test outside the specific window still has some merit as a positive animal will always be positive and has no place in a pedigree breeding herd, whereas a negative result outside this window may be less reliable.
- bovishas been found in several wild mammal species. High rates of infection have been found in badgers, and the consensus of scientific opinion is that badgers are a significant source of TB in cattle in the UK herd. However, there appears to be a relationship between the type of landscape (e.g. south west England) and the risk posed by badgers. Animals are probably more likely to be infected by M. boviswhen they are poorly nourished or under stress. Growing heifers and younger cows are most at risk.
- bovisis spread in a number of ways by infectious animals – in their breath, milk, discharging lesions, saliva, urine or droppings. In cattle, excretion (Infectious stage) of M. bovisbegins around 87 days after infection occurs. Entry is usually by inhalation (especially if housed) or ingestion (when badgers are the source of infection). Once in a herd, infection probably spreads from cow to cow by inhalation. Spread from cows to calves may occur via the milk or colostrum.
Various body systems can be affected, but signs are usually confined to the respiratory tract. A soft, chronic cough occurs once or twice at a time. In more advanced cases, there is a marked increase in the depth and rate of respiration as well as dyspnoea (difficult or laboured breathing). Areas of dullness can be heard in the chest on auscultation (Listening with a stethoscope) or percussion. Some cases may squeak, whistle or have a snoring respiration.
Diagnosing bovine tuberculosis is complicated, and a diagnostic gold standard that can detect all infected animals is not currently available. Conventional diagnostic tools (i.e., detection of antibodies or antigens) can be used only in the late stages of the disease. Consequently, the most widely used first bovine tuberculosis diagnostics are based on the cell-mediated immune response, which is determined by either skin or blood testing (IFN-y test). You can find more information about the blood test by following the link below:
Differences exist among bovine tuberculosis tests with respect to the time point and the sensitivity for detection of the disease. The IFN-y test (i.e., BOVIGAM assay) allows for the earliest detection, followed closely by the skin test. Serology tests for antibody response or antigen detection and pathological examinations can be used in later stages of the disease. You can find out more about this Veterinary use only test by following the link here:
PCR is a reliable diagnostic tool for confirmation of the presence of mycobacteria belonging to the tuberculosis complex. Results using the PCR approach can be returned much faster when compared to bacterial culture testing methods. While the results of a M. bovis culture can take up to six weeks, results using PCR – from sample preparation to testing – take just three hours. The information is then delivered to the farmer or veterinarian in two to three days. For more information on the PCR testing method click on the link below:
The choice of tests and their applications is dependent on both the risk of bovine tuberculosis infection in a region and the goal of a bovine tuberculosis program. Optimal TB programs enable sanitary decisions to be made sooner, increase the speed of a test and cull program and helps minimize the duration of farm closures. The TB hub is the ‘go-to’ place for British beef farmers to find practical advice on dealing with bovine TB on their farm, covering everything from biosecurity measures to understanding trading rules:
CHeCS bovine TB herd accreditation health Scheme for buyer reassurance: