SELLS Animal health update November/December 2021

South East Local Land Services District Veterinarians

Your District Vet is a source of impartial advice and work with your private practitioner 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 over the last month.

Staffing

We congratulate Henry Clutterbuck on his recent wedding, but it is with great sadness that we farewell Henry from the LLS at the end of this year as he has earned a position studying Medicine. Petrea Wait has been granted a 12-month extension on her recruitment to DPI.  We welcome Peter Rolfe to the District Vet team at Yass, commencing a job share with Alex Stephens. Peter comes with wealth of experience due to a long and distinguished career. We are currently recruiting to fill the Cooma and Goulburn District Vet positions and we thank producers for their patience while these positions are vacant. 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

Lead toxicosis

A steer which died after showing neurological signs including aimless wandering, blindness and tongue protrusion and repeated licking was diagnosed as having been poisoned by lead. One other steer in the small mob also had high lead levels on blood tests. These inquisitive hand-raised young steers had accessed an old shed which was storing several lead-containing items including old batteries. Old lead acid batteries are the most common cause of lead poisoning in livestock. Battery cases become brittle over time and are easily broken by cattle. The lead and lead salts that they contain are easily accessed and readily licked or eaten by stock. Stock exposed to abnormal lead intake must not be slaughtered for human consumption until their tissues meet food standards. For more information go to www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/health-and-disease/general/lead-poisoning-in-livestock

Fluke and selenium deficiency

An investigation into substandard growth, poor body condition and retained winter coat in a mob of yearling steers revealed evidence of both liver fluke infection and selenium deficiency. A blood test for liver fluke antibodies is available, which detects evidence of the immune system reacting to the presence of the parasite. GSHPX levels, which test for selenium deficiency, were very low in this case. The normal range for this test is 40 – 300 units, and the range of results in this cohort were ranged from 2 to 7. A long-acting injectable selenium supplement and a fluke-specific chemical drench was recommended for all steers, heifers and cows on the property.

Factors which make selenium deficiency more likely are:

• Granite-based or sandy soils
• Acid soils
• Higher rainfall areas of Australia, or periods of high rainfall
• Time of year, with levels being lower in spring and higher in autumn
• Clovers in the pasture
• Young animals (growth has a higher requirement for selenium)
• Any practice that intensifies and improves pasture production such as application of fertilisers, cropping or sowing
• High stocking rate
• Change from drought conditions to lush pasture growth

Weaner ill thrift

A case of weaner ill-thrift and mortalities has been investigated in Autumn born merino lambs. Internal parasites have been challenging the sheep on the property for the past 12 months, since the wet weather. It was thought likely that the ewes of these lambs produced less milk because of worm burden, resulting in lambs grazing more to compensate for poor milk supply. Because lambs graze behind their mothers they will have picked up infective worm larvae hatched from worm eggs dropped onto pasture from ewes. The worm parasitism of lambs reduced feed intake and growth, resulting in weaners with no stores of fat and unable to unable to withstand the stressors of weather. It is thought that drench resistance has also played a part in this problem. Effective drenching, frequent worm egg count monitoring and nutritional support has been provided in response.

Theileriosis

Theileriosis has been a significant issue for coastal cattle this spring/summer. Introduced/naïve stock are most at risk and cases have been occurring in locally born calves and introduced cattle. Theilieria Ikeda is a blood-borne parasitic organism transmitted between animals by vectors, mostly ticks but also other biting insects.  It causes a breakdown of red blood cells and anaemia which results in ill thrift and extreme lethargy and can, in worse-case scenarios, cause abortion and even death. Using pour on Deltamethrin products to control vector numbers seems to help in reducing numbers affected in an outbreak.

Barbers pole worm

With the rising temperatures > 15°c barber’s pole worm numbers are on the rise, and infections are building quickly. Counts are rapidly rising, and in many cases these counts are a mixed infection of barber’s pole and scour worms. Faecal egg counts (worm egg counts) are our best weapon against internal parasites.  Conditions are so ideal for worms we recommend using FECs to monitor your mobs every 4-6 weeks during the spring/summer and taking early action on worms.

Anal prolapse in sheep

Several Aussie white breeders have reported issues with anal prolapses in their ewes this spring. Although causes of this problem are multifactorial and high protein feed was contributing, short tail docking has also contributed. Aussie white and dorper type sheep should not need to have their tails docked at all for fly control. If they are docked, they should be docked to the third coccygeal joint, similar to merinos. This preserves the innervation to the anal and tail area, maximising fly control and minimising prolapses.

Foot rot in sheep

Continued rain has put continued pressure on feet, with conditions being ideal for both benign and virulent footrot, caused by the bacteria Dichelobacter nodosus. There are many different strains with variable amounts of power to underrun the heel and damage feet.   Foot rot is a notifiable disease, meaning that you must call your local District Veterinarian if you notice lame sheep and underrunning of the hoof at the heel. The District Vet will look at the proportion of sheep that are affected, and how severely affected they are, to classify the disease as benign or virulent. They will then work with you to develop a short and long-term plan to minimise and eliminate the disease if required. Foot bathing is a very effective management tool. 10%-20% Zinc sulphate is the most frequently used chemical. To use it most effectively it requires a contact time of at least 5 minutes, followed by at least an hour of drying time. For more information review our Fact sheet.

Take great care when restocking that you don’t buy foot rot in.  Keep any new sheep that you have purchased isolated from the rest of the flock until the end of spring.  Ensure your boundary fencing is good and that you check all strays.

FLY STRIKE TREATMENT AND PREVENTION

Alexandra Stephens District Veterinarian Yass

Flies are becoming a major issue again this spring/summer. To understand fly control, it is important to understand the fly life cycle.

Each season we grow our own green strike flies from pupa burrowed in the soil from the previous season. The adult flies are attracted to the smell of wet wool and lay eggs which become maggots and eventually drop off and burrow back into the soil. The fly wave then builds as warm temperatures speed up the life cycle and as each fly successfully lays more maggots. Unfortunately, last year's bad fly year will contribute to more fly problems this year.

Prevention of a fly wave is about preventing flies from striking sheep, by minimizing strike opportunities of wet smelly wool through shearing, crutching, conformation, sheep selection, chemical application and prevention of scours. It is also about monitoring sheep regularly and preventing strike maggots getting back into the soil. Purchase quality electric clippers, clip off the area of strike before you apply chemical and place the maggoty wool in a bag to seal and leave in the sun to kill the maggots.

Not only does this help to prevent the build of the fly wave it also greatly delays the development of resistance.

Best practice principles to delay resistance

1. Use an integrated approach to decrease your reliance on chemicals: breed for resistance to flystrike, shear or crutch at times that maximise protection against flystrike, dock tails to correct length, use breach modification if required, manage scouring.
2. Minimise number of insecticide applications: utilise other management strategies, such as shearing and crutching, to minimise the length of time flies may be exposed to inadequate levels of insecticides on the sheep.
3. Application: Shorter protection periods are often due to poor application, not resistance. Be sure to apply insecticides carefully according to the label instructions. Watch particularly for rain after application.  Poor application can expose flies to sub-lethal levels of insecticides; this can contribute to an increase in resistance.
4. Monitor regularly for flies: Check sheep every 2–3 days during high-risk periods to identify struck sheep early. Treat sheep and kill maggots before they become larger and are harder to kill, or drop off and pupate. Document when strike occurs in relation to preventive treatments and send maggots for resistance testing if required.
5. Collect and kill maggots- Clip struck wool from sheep before treatment.Place maggots and shorn wool into a sealed plastic bag and leave in the sun so the maggots are killed.
6. Utilise Flyboss.com to plan your chemical applications and management to maximise fly strike control
7. Rotate your chemicals: use a different chemical for treatment of struck sheep to treatment for prevention.  If you need to apply multiple fly treatments over a summer, try to rotate chemical groups.
8. Know your Chemical groups: when looking for alternatives, change to a different chemical group, don’t just change insecticide brands.
9. Rotate away from lice treatments: exposure to insecticides used for treatment of other parasites (particularly lice) can contribute to resistance selection in blowflies, and vice versa. Where possible, use a different chemical group to treat flies and lice.

Know Your Chemical Groups - Blow fly strike preventative options

Know Your Chemical Groups - Blow fly strike treatment options (must kill maggots)

ARE YOU WORRIED ABOUT WORMS?

Lou Baskind, District Veterinarian

This season has been very favourable for the development of internal worms in animals. Worms are parasites, which means they derive nutrients from the host at the expense of that host. They cause damage to the stomach or gut lining, interfering with appetite and nutrient absorption, and can cause diarrhoea. The host animal suffers malnutrition by not eating enough and by having nutrients “stolen” by the parasite.

By the time you visually observe the external signs of worms in livestock, such as weight-loss or diarrhoea, much damage has already been done. Before these signs are seen, animals with worms are producing less milk, wool, growth or muscle, their immunity is suppressed, and their reserves are being used up. All this can be happening without you even knowing it!

So, waiting until you see diarrhoea to indicate it is time for chemical treatments can be a dangerous game. As well as the damage already done, sheep with dags (staining of the breech with diarrhoea) are very susceptible to fly strike. Fly strike is a horrid condition with serious welfare implications. So, it makes sense that identifying a worm problem early allows you to manage it before there are significant welfare and economic impacts.

There is an easy way to know for sure if your animals are suffering under a worm burden - it’s by having the microscopic worm eggs in a sample of fresh dung examined and counted. Worm egg count tests (WormTests) are provided by the State Veterinary Diagnostic Laboratory as well as several commercial testing providers and some local veterinarians.

Simply pick up a testing kit from the Local Land Services office, order kits from the State Veterinary Diagnostic Laboratory website or contact a private testing provider for a kit. The kit has all you need including instructions, sample jars and the post bag to return your samples to the laboratory. Testing for horses and livestock costs around $100 and provides the egg count result for 10 dung samples as well as defining the proportion of different species of worms.

Get yourself on the front foot by using WormTests to regularly monitor the level of parasitic worms in your livestock and horses. I guarantee this will help you to implement better worm management strategies such as grazing management and effective (but not excessive) chemical drenching.

For more information about worm monitoring, treatment and prevention, contact your Local Land Services District Vet, local private veterinarian or agricultural advisor.

Paraboss also has plenty of information to help learn about parasite control.

IS YOUR CALVING PADDOCK UP TO SCRATCH THIS YEAR OR NEXT?

Evelyn Walker, District Veterinarian Berry

There have been increased reports of arthritis, respiratory disease and scours in young calves. Most of these infections are picked up at the time of calving or shortly thereafter. Bacteria and viruses can enter a susceptible calf via the naval, sucking on a dirty udder or via inhalation or ingestion. These cases appear more frequent in cooler wet seasons when plenty of feed about.

Given this unusually wet season, care should be taken to manage the calving and calf environment as much as possible. By implementing the below strategies, you can help reduce your disease risk.

Are there any high-risk areas in your calving paddock? Overstocking, poorly draining areas, waterlogging, mud, poo and water accumulation are all breeding grounds for pathogen exposure. Ensure water troughs are not leaking. If using hay rings or round feeders, regularly move them to avoid mud and poo accumulation.

Are your boots wet or muddy all day? Either of these conditions are too dirty to calve in. Imagine how much mud would accumulate on a 500kg cow with big teats.

Asses your paddock rotation practices. Avoid using the same calving paddock year after year as some virus and bacterial pathogens can live in the environment for up to 12 months. If you are strip grazing or shifting the fence regularly of your calving herd, any more than two pats of poo per square metre is too much.

Ensure calves get their first drink. Newborn calves should be up and drinking within 30 minutes to a few hours of being born so they get adequate colostrum. (The colostrum window closes after 24 hours.)  If your cows are quiet and handled often, spraying the navel of neonatal calves with iodine may also help reduce infections entering via the navel. If you notice young calves at foot that are ill or not quite right, early veterinary treatment is best to ensure calf survival.

CONTACT US

To get in touch with you district vet, visit our contact us page for local office contact.