South East Local Land Services animal health update June 2022

03 Jun 2022

South East Local Land Services District Veterinarians

Your district vet is a source of impartial advice for herd health and welfare concerns on your farm. They provide over the phone advice, property visits and veterinary sampling where required. They work with your private practioner veterinarians, rural resellers and agricultural advisors to provide you with an accurate diagnosis of the cause of disease and treatment and prevention options. The monthly surveillance results share the significant cases seen and reported over the last month.

Staffing

Recruiting is still under way to fill the Cooma district vet position. Please ring the office if you have an enquiry and you will be redirected to an available vet on our team. We aim to get back to all enquiries promptly but please allow extra time for us to return your calls and for interstate and export documentation.

South East monthly disease surveillance results

South Coast update-cattle

Due to continually wet conditions, ongoing cattle health issues of concern on the South Coast are mastitis, lameness, three-day sickness, theileria, pneumonia, worms and liver fluke. In previous seasons, small intestinal worm (Cooperia) was more common in young cattle in the district, but recently barber’s pole worm (Haemonchus placei) has been reported in calves. The barber’s pole worm is a blood sucking worm that has the potential to be fatal in immunosuppressed cattle especially young calves and first lactation cows. You will not see scours with this type of worm and may see signs of ill-thrift, profound lethargy and anaemia (pale or white gums or conjunctiva). This worm has the potential to be the ultimate deadly combination especially if calves are battling an underlying theileria infection.

To know how much Haemonchus placei is present on the South Coast, we would need more producers to request a larval differentiation (also referred to as larval culture) on their cattle worm test. The larval differentiation takes longer because the lab incubates the worm eggs to see what types of worms grow. Knowing this extra information is beneficial. For example, some species of worms have known resistance issues and not all worms have the same health or economical impacts on production. A drench may or may not be required. Your Local Land Services district veterinarian or private veterinarian can assist you in this decision-making process.

Barbers pole worm-sheep

The mild and wet conditions have continued to see barbers pole worm and flies cause immense problems across the Tablelands, Monaro and down the South Coast. Please don’t hesitate to consult with us to work on a plan for better parasite management if you have had issues.

Grass tetany (Hypomagnesaemia) in cattle.

Vets and producers in the tablelands area have been reporting confirmed grass tetany deaths in cattle. As winter approaches the risk of grass tetany many get even higher with colder, wet soils, low legume levels in pastures and weather fluctuations. Cold weather followed by warmer days favours potassium uptake by fresh grasses. Plants containing high levels of potassium block magnesium (Mg) absorption in the rumen leading to an acute Mg deficiency. For prevention options and more information read the article in the April animal health update.

Gudair staggers in weaner sheep

The Gudair vaccine is used to prevent Ovine Johnes disease. The vaccination is oil based and if injected into muscle it can causes a large tissue reaction. Administration is advised to be subcutaneously high on the neck, behind and below the base of the ear. Incorrect injection into the midline of the neck can lead to an abscess which grows and migrates towards and into the spinal cord causing progressive paralysis. Signs of Gudair staggers can be seen in weaner sheep with weakness and swaying gait in the hindlimbs which progresses to collapse and death.

Watch these instructional videos that demonstrate best practice vaccination.

Photosensitivity in lambs grazing Brassica

Grazing brassicas are an extremely useful crop, high in protein and energy, but certain toxins within the plant can cause photosensitization. Lambs are most susceptible to this condition. It is important to avoid grazing premature plants and monitor stock regularly. If signs of photosensitivity are noted, remove affected animals from the crop and provide shade. When grazing brassicas, it is also important to always supplement with ad lib roughage. Read more about photosensitisation in stock.

Risks of introducing cattle from out of area and interstate

Lucy Creer, final year Veterinary Science CSU

Buying and agisting cattle from different states and climates is something that is occurring more frequently as producers restock their properties and build up their cattle numbers post drought. Unfortunately, this can incur the risk of transferring diseases from other areas. Being aware of the hazards is important to get the best from the stock brought in and to protect your own herd.

Frequently encountered risks

Theileriosis

Theileria is a blood borne parasite that is carried via insects but most commonly the bush tick. When the tick bites the cattle, the parasite is injected into the blood stream where it infects red blood cells. Once in the red blood cells the parasite destroys them causing severe anaemia which can result in death. It is normally found (endemic) in coastal regions of NSW, QLD and VIC however it is being found more commonly inland of these states.

In these endemic regions, if herds that are born and raised there, they are exposed to the disease early in life and they can go onto to recover and develop lifelong immunity. However, when inland cattle herds that have had no exposure (and have no immunity) encounter a tick or biting insect carrying the disease, they become infected and are likely to suffer from severe disease and death is much more likely. Young calves, heavily pregnant and recently calved cows are most at risk. Diagnosis is most commonly made via a PCR blood test. There is currently no registered treatment or vaccination for the Theileria. If moving cattle from ‘bush tick free’ areas (Southern/Western parts of NSW and Southern states) the cattle are most at risk of developing the disease 6-14 weeks after introduction. For further reading visit the Meat and Livestock Australia website.

3 Day Sickness in Cattle

Bovine ephemeral fever (BEF) or ‘3 day sickness’ is a viral disease that is spread by mosquitoes and biting midges. The disease is usually found in northern and coastal regions of Australia however due to the increased rainfall across much of Eastern Australia, mosquitoes and midges are carrying the disease further inland and south.

The name comes from the duration of symptoms typically lasting 3 days; these symptoms include sudden onset of fever (temperature up to 41 degrees Celsius), depression, lack of interest in feed, muscle stiffness, reluctant to move, drooling of saliva, nasal discharge and recumbency. Lameness is one limb only appearing on the second day is a common feature. By the third day the animal is usually standing again however lameness can persist. Young stock are more commonly affected but heavier, pregnant and older stock are more severely affected. Diagnosis can be made on clinical signs or via PCR through a blood test.

Non-lactating or young stock may not require treatment, but treatment will be required for bulls, pregnant and well condition cows. Nursing care is particularly important in animals that are recumbent, as muscle wastage and nerve injuries can become long term damage. Nursing care includes feed, shelter and water being provided, as well as the animal being rolled over several times a day to avoid loss of circulation to the underside limbs. Anti-inflammatories are recommended in recumbent animal as well as calcium injections if the disease is caught early on. Once infected, cattle will develop life long immunity and are unlikely to be reinfected. Vaccination is available at $15-20/ dose (2 doses required) and is recommended to be given prior to the wetter seasons. If vaccination of whole herd is not achievable, it is recommended to vaccinate the high value animals. For further information please the NSW Department of Primary Industries website.

Respiratory disease

There has recently been an increase in cases noted to have bovine respiratory disease (BRD). Bovine respiratory disease is an umbrella term encompassing a number of different viral and bacterial diseases affecting the respiratory system in cattle. It is a major disease seen in feedlot situations due to stress and close proximity of cattle. However, stress is the main factor that exacerbates BRD which means that non feedlot systems are also at risk of obtaining the disease. Commonly stressful situations which can predispose animals to BRD are:

transporting
yarding
handling
change in climate (big fluctuations in temperature, environment, dust)
mixing of groups or changes in social hierarchy.

Younger cattle have less resilient immune systems, so weaning is a particular time to look for BRD. Viruses and bacteria in the back of the throat begin to damage the windpipe. This then allows bacteria to enter the damaged lungs and cause pneumonia. Often the first signs of BRD may be sudden death. Early clinical signs of BRD are an elevated temperature, slow and lethargic stock, watery nasal discharge, occasional cough. As the disease progresses signs are:

harsh cough
cloudy nasal discharge
dull
standing on their own
short shallow breaths
low outstretched neck.

If any of these signs are noted, the private or district vet should be called. Treatment may involve anti-inflammatories to assist with the fever and antibiotics to target the bacteria. Vaccinations are available however need to be given before an outbreak and should be used in conjunction with management strategies that reduce stressors as much as possible. For more information read this article on bovine respiratory disease.

Pestivirus

Bovine viral diarrhoea virus (BVDV) more commonly known as ‘Pestivirus’ is a widespread problem throughout the Australian cattle population. Up to 90% of herds will be exposed to the virus at some stage, and up to 60% of cattle will show prior or active exposure. There is a risk that you can introduce this virus to your herd when you buy in cattle, particularly young trade steers or heifers which may include a persistently infected calf (PI).

The economic cost of the disease is high due to disruption to reproduction if cattle are exposed to the virus while pregnant. Cattle can become infected via exposure to bodily fluids from an infected animal (Saliva, urine, nasal discharge, uterine fluid, milk, semen, faeces) or via contact with an aborted foetus from an infected cow. If a healthy, non pregnant animal gets the virus it is unlikely you will notice the virus is even present within the herd. These animals will build an immune response and will recover from the infection, then they are protected for life from the virus. Losses occurs when cattle are infected for the first time during pregnancy. The stage of gestation will affect the outcome for the cow/ calf. Reproductive loss, abortions, still births, delayed conceptions, deformed calves, PI calves, ill thrift/ stunted growth, diarrhoea and death are all possibly outcomes to the foetus of a cow that acquires pestivirus while pregnant.

Diagnosis can be made via taking blood, an ear notch or a tail hair sample. Vaccinations are available and recommended. To discuss the merits of vaccination in your herd, please contact your Local Land Services distract veterinarian or private veterinarian. For more information read NSW Department of Primary Industries primefact on bovine pestivirus infection.

Barber’s pole worm in Cattle

Barbers pole worm of cattle (Haemonchus placei) is a blood sucking parasite commonly found in Queensland and northern half of NSW where summer rainfall is dominant. Animals get infected with the worms through eating pastures contaminated with the worm larvae. The ingested larvae mature and survive in the abomasum (the last ruminant stomach) through sucking the blood of the animal. They can suck 0.05ml of blood per day. Signs that an animal has a high worm burden are anaemia, lethargy, ill thrift, failure to gain weight, bottle-jaw (swelling under the jaw) and death.

There has recently been an increase in resistance of Barbers Pole worms to single acting mectin and white drench actives. To target these resistant worms, it is advised to use the more potent of the mectins (Moxidectin) in combination with Levamisole or a triple action drench. The best way to determine to effectiveness of the drenches is via sampling fresh faeces for worm egg counts.

South East Paraboss State Outlook (May)

Evelyn Walker, District Veterinarian South Coast - Berry

On the South Coast, worm egg counts have been staggeringly high in all ruminant species including mixed ages of sheep, goats and alpacas and in young cattle. Worm types have varied across the South Coast with mixtures of barber’s pole worm, black scour worm and brown stomach worm. Symptoms reported in all species have included sporadic deaths, ill-thrift, weight loss, slow to muster, collapse, anaemia (low red blood cells) and no symptoms at all. Please do not wait until you experience symptoms in your herd or flock before taking action. Use regular worm egg counts as a monitoring tool to detect potential worm problems lurking in your animals well before they display signs of ill health.

Your worm egg count results and your larval differentiation (also referred to as larval culture) results are equally valuable as proactive tools to use. You can make some determinations on the following:

the level of worm burden present;
the actual worm types present;
whether a drench is required;
how soon you need to prioritise drenching
how soon you need to do a repeat worm egg count if results indicate drenching is not warranted.

During these exceptional times of prolonged wet conditions coupled with mild temperatures, combined with a lack of available low worm risk paddocks or unsuitable paddock conditions, for example (e.g. water logged, damaged feed, etc.), many have been forced to put stock back into heavily worm contaminated paddocks or less than ideal paddocks. I encourage everyone to be doing regular worm egg counts every 4 to 6 weeks during this time.

Beware drench resistance is common. There have been a few cases where producers have been caught out using older single active ingredients which only marginally reduced their worm burdens in their stock. If you are unsure of your chemical effectiveness for your property, a drench check 10 to 14 days after drenching is highly recommended. This will give you an idea of how well the drench you administered to your stock actually worked. The results of the post drench check will give you some clues to possible drench resistance on your property. A single chemical might be ineffective on one or several worm types. And remember, every property is unique in terms of worm burden, worm types, animal susceptibility and drench effectiveness.