Riverina District Vet Newsletter | December 2022
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District Dashboard
The most common diagnoses made by our team over the past month and what we expect to see coming over the horizon...
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Strawberry Footrot
With wet conditions and lush pastures, we are seeing an increase in Strawberry Footrot, abscesses and lameness in sheep.
Read more about this here
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Scabby Mouth
With lush conditions again, scabby mouth is appearing in the district. Some as mouth lesions, others as foot lesions. While it doesn't directly cause deaths, is can affect production (weight gain) and can be zoonotic (cause illness in humans)
Read more about this here
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Worms
With favorable wet, lush seasonal conditions, we are seeing some high worm burdens and associated stock losses. Below is a link to Worm boss for when to wormtest, and when to drench, including a link to their drench decision guide
Read more about this here
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What we're looking out for
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Pulpy kidney
Please make sure your lambs have had their booster vaccination at least a month after marking, before entering lush pastures.
Read more about this here and here
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Red gut
Red gut is a severe intestinal accident seen in sheep grazing lush green pasture
Read more about this here
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Case Study: Anaemic Anomalies
By Kelsey Sibley, District Vet
Case History:
Recently, a producer lost 15 Merino lambs in a mob of 900 over a couple of days, plus a few deaths in other mobs. These lambs had been marked and vaccinated with 7-in-1 six weeks prior and were yet to be weaned and have their first drench. The producer had noticed some lambs had dropped in condition, while others were lethargic and noticeably pale.
Post-mortem and diagnosis:
A post-mortem was performed on a lamb that had died that day– it had very pale conjunctiva around the eyes, thin watery blood and live Barbers Pole in the abomasum. The lamb was in reasonable body condition and no abnormalities were detected otherwise.
The producer completed a worm egg count (WEC) to determine the extent of the worm burden across three mobs, however Mob 1 with lambs which appeared worst affected had the lowest average egg count. A larval culture would have been helpful in this case to differentiate between worm types, however it was not available where the WEC was conducted.
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Average Worm Egg Count |
| Mob 1 (worst affected) |
414 epg |
| Mob 2 |
618 epg |
| Mob 3 |
1014 epg |
To work out why Mob 1 was seeing the most animals affected, blood samples were then taken from 15 randomly selected lambs in the paddock to avoid taking lambs all the way to the yards. Blood was tested for Mycoplasma ovis and it was detected in this mob (other mobs were not tested).
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Above: Blood smear showing M. ovis (purple spots) in the red blood cells of sheep. (Sourced from Peter A. Windsor, 2022, ‘Anaemia in Lambs caused by Mycoplasma ovis: Global and Australian Perspectives’)
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What does this mean?
Mycoplasma ovis is a type of bacteria that invades the red blood cells of sheep, causing destruction of the blood cells and subsequent anaemia.
It is spread through blood, so therefore marking, mulesing, vaccination (needle sharing), ear tagging, shearing, crutching and insects such as mosquitos are important vectors for transmission. Infections can occur in any age group, however it is most common up to 6 weeks after marking in lambs. Lambs are most often affected due to lack of immunity, but other factors such as nutrition, and presence of concurrent infections (in this case, Barber’s Pole worm) can worsen the condition. Lambs with heavy M. ovis burdens may show clinical signs beofre 6 weeks.
Clinical signs include ill thrift, pale gums and conjunctiva around eyes, jaundice, lethargy and exercise intolerance, particularly when lambs are stressed or mustered, and death.
Diagnosis of M. ovis is made by considering history and clinical signs, ruling out other causes of anaemia (eg. Barber’s Pole worm and liver fluke) and through blood testing. In this case, the combination of Barber’s Pole and M. ovis likely compounded each other, resulting in a severe anaemia and deaths.
What can be done to prevent and manage it?
Unfortunately, there is no reliable treatment for M. ovis infections as antibiotics are ineffective, so therefore prevention and management is important.
Prevention is aided by good hygiene around risky practices – ensuring needles are changed frequently when vaccinating and keeping gear clean while marking and mulesing. The current booming mosquito population may make the prevention of insect vectors tricky, however reducing access to stagnant water may help.
If a diagnosis is made, then management practices may need to be altered to reduce stress and subsequent losses from M. ovis. With lambs, yarding or movement should be avoided for six weeks after marking or mulesing. Ensuring lambs are healthy by providing good nutrition and worm control will also help to reduce the impacts of M. ovis.
The management plan for these lambs was to leave them alone for two weeks to build immunity to M. ovis and ovoid further stress, then drench and wean them.
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Would you like flies with that?
By Grace Bond, CSU Final Year Veterinary Science
Given the current wet and humid start to summer, flystrike is expected to be a problem for many producers. It is important to be aware of the signs of flystrike as well as best practice treatment. Controlling flystrike leads to better health and welfare outcomes for your sheep as well as farm profitability.
When to monitor for flystrike?
Flystrike is most likely to occur following heavy rainfall or flood events. These conditions favour the breeding of blow flies. The moist wool can develop fleece rot which attracts blowflies to lay eggs on susceptible sheep.
General clinical signs:
- Sheep showing signs of irritation and discomfort (biting, scratching, leg stamping, ducking head)
- Lighter coloured wool from chewing/rubbing, wool becomes progressively darker
- Depression of wool
Advanced strikes will appear as:
- Signs of systemic illness (depressed, weight loss, recumbent, not eating/drinking)
- Large areas of strike wounds
- Visible maggots
- Swollen, inflamed skin
What to do if you find a struck sheep?
Any sheep suspected or identified with fly strike should be pulled from the mob immediately. These sheep should be examined closely.
Once identified…
- Clip the area with wide margins to allow the skin to dry out and remove all maggots
- Place the clipped wool and maggots in a black plastic bag in the sun to allow it to dry out and kill the maggots
- The struck area should be treated with a registered flystrike dressing
- Remove struck sheep from mob and run separately to reduce the risk of attracting flies to the mob
Prevention
There are a range of chemicals available to treat flystrike. As flies can develop resistance to chemicals, it is best to use an integrated management plan. To reduce the risk of resistance developing, you should not apply the same chemical class for treatment within a single wool cycle.
The best time to apply a flystrike preventative to the flock is during winter, however continuing preventive measures must be considered throughout the fly season. An integrated management plan involves chemical application, along with shearing, crutching and/or breech modification to further reduce the risk.
Shearing/crutching can provide up to 6-weeks protection against flystrike. This should be performed prior to the first fly wave occurring.
Good worm control via drenching is also important to minimise dags and reduce the risk of flystrike.
Flystrike is highly repeatable, therefore, in the long term, the best solution is to breed sheep that are less susceptible to flystrike. Wrinkles, breech cover and dags all increase the moisture on the skin, which attracts flies.
FlyBoss.com.au is a useful resource for further information about flystrike. There are useful tools to assess the effectiveness of particular chemicals in reducing the risk in your flock.
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Staying out of trouble with stubble
By Alexandra Thompson, CSU Final Year Veterinary Science
Coming into the summer months post-harvest it becomes the time of year where mixed farming enterprises utilise stubble pastures as a feed source for stock. The nutritional value of stubble varies widely due to crop species and variety, climate, soil management and paddock conditions but they can be utilised to minimise the summer feed gap. However, it is vital for producers to be aware of any potential animal health risks associated with the practice so proactive measures can be taken against them.
Key considerations prior to utilising stubble as a feed source:
- The quality of stubble alone is consistently below maintenance for commonly grazed crop species (barley, canola, lupins, wheat). Because of this, the majority of feed value comes from residual grain in the paddock which can vary greatly from stubble to stubble
- Prioritise ewe lambs on the highest quality stubbles, followed by pregnant ewes (or ewes prior to joining). Older or dry ewes should be given lower quality stubbles (e.g. wheat and canola)
- Utilise a rotational grazing system which allows high stocking rates for short periods of time on stubble pastures. This gives the best utilisation of feed resources and helps preserve ground cover and limit erosion by minimising overgrazing of particular areas
- Supplementary feeding will help increase utilisation of low-quality stubbles and reduce weight loss of sheep as stubbles become depleted
- Stock require 14% crude protein in their diet which is often not met with stubble grazing alone (typically <10% protein)
- Prolonged grazing of stubbles can contribute to low vitamin E
- Supplement salt: this will increase salivation and bicarbonate production to buffer against acidosis (see below)
- Acidosis: sheep are at risk if they are consuming large quantities of grain suddenly. Where possible provide slowly increasing grain supplementation (50-300g/hd/d) over two weeks prior to stubble grazing. Alternatively graze the sheep on barley or lupin stubbles first as they contain more fibre and less starch
- Annual ryegrass toxicity (ARGT): this is a cumulative toxin, building up in the body over time as it can’t be eliminated. Incidence in stubbles varies greatly but testing of stubbles that contain high levels of ryegrass seeds or in areas where ARGT has occurred before is recommended
More information about grazing stubbles can be found at:
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Are your animals fit to load?
By Grace Bond, CSU Final year Veterinary Science
With strong sheep and cattle prices at the moment, livestock are very profitable. Ensuring fit and healthy animals prior to transport is beneficial to both the producer and purchaser. Current consumer demand includes a high animal welfare standard. A way to achieve this is to ensure animals are fit and healthy prior to being transported.
Role and responsibilities
There is a chain of responsibility for the welfare of livestock in the transport process, this involves:
- The consignor- responsible for assembling animals and ensuring livestock are fit to load
- The transporter- responsible for the final inspection if the animals are fit to load, loading density, spelling periods and unloading
- The receiver- responsible for the animals after unloading
The person ‘in charge’ of the animals is responsible for the welfare of the animals.
How to assess if an animal is fit to load
Before livestock load, ensure this checklist is completed:
The animal…
- Can walk on its own bearing weight on all 4 legs
- Is free from visible signs of severe injury or distress or conditions likely to further compromise its welfare during transport
- Is strong enough to make the journey (e.g. not dehydrated or emaciated)
- Can see well enough to walk, load and travel without impairment or distress (e.g. is not blind in both eyes)
- Is not in late pregnancy or too young to travel
- Has had adequate access to water prior to loading to meet the maximum time off water standards
If all boxes are ticked, the animal is fit to load. If in doubt, leave it out! If one or more boxes are unticked, the animal is not fit to load.
What to do if the animal is not fit to load
- Treat the animal and reassess, then once recovered and fit to load, the animal may be transported
- Consult a vet and then only transport under veterinary advice
- Euthanise the animal
Ensuring your livestock are fit to load, not only helps meet the legal obligations required for transporting livestock, but benefits the livestock industry and helps meet consumer demand.
Information interpreted from Meat and Livestock Australia (MLA) guide ‘Is the animal fit to load?’
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Upcoming Events
MERRY CHRISTMAS & HAPPY NEW YEAR FROM THE LLS VET TEAM
Thanks for your support over 2022 in keeping our local livestock industries healthy and safe!
Our offices will be closed from 4.30 pm Friday 23 December 2022 for the Christmas break and will reopen at 8:30 am Monday 9 January 2023.
For life threatening emergencies, please call 000 immediately.
If you suspect a significant animal pest, disease, or residue or experience a large number of unexplained livestock deaths, please contact the Emergency Animal Disease Hotline on 1800 675 888.
If you need to report an exotic plant pest or disease, please call the Plant Pest Hotline on 1800 084 881.
For assistance with non-emergency livestock health issues, please contact your nearest private vet.
Enjoy the Christmas break, stay safe and we look forward to seeing you in 2023!
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Contact us
WAGGA - Dione Howard – 0428 115 134 or 6923 6300
GRIFFITH - Georgia Grimmond – 0427 418 006
Jess Dalton (Tues, Wed) – 0427 696 895
HAY - Elizabeth Ferguson – 0439 557 567
GUNDAGAI - Kristy Stone (Tues, Wed, Thurs) – 0428 262 112
TEMORA - Bianca Garnham (Mon, Wed) – 0455 489 296
Victoria Buck (Thurs, Fri) – 0457 332 736
YOUNG - Kelsey Sibley – 0499 546 389
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