SELLS Animal Health Update March 2020

March 2020

LOCAL DISEASE WATCH

Alex Stephens District Veterinarian Yass.

How great is the rain!! Such a change in circumstances in a month has brought welcome green feed and relief to water stresses on many farms. With the summer rainfall we have a new list of diseases seen last month and to be aware of for the month ahead.

Vit A, D and E - At the beginning of this month, due to the extended dry, we were investigating cases of tails in feed lot situations. The results showed young animals being fed grain and hay since weaning had become deficient in Vit A and E. Animals being maintained in feed lot situations require an A, D and E booster every 3 months if they had not had access to green pick. Where sheep are getting green grass for a few weeks their levels of Vit A, D and E should be okay.

Malnutrition - When feed is very short or very fresh, we often still need to continue supplementary feeding our stock until the pasture bulk has increased. Cows that did not have their calves weaned early and had not been receiving supplementary feed, will have fed their caves with the fat and then muscle off their backs. They now have minimal reserves. Cows that have gotten to condition score 1/5 will need to have their calves weaned and be fed to improve their condition before they can be sold through the yards or trucked long distances. Feeding 10% roughage in a sheep feedlot situation will help to maintain ruminal health and look after the tail end of fussy eaters. Without this, your death rate will be higher. Early weaning of calves was a very good idea this year, but attention to the type of diet they were fed was important. Young stock require minimum protein and energy levels in the diet and have a higher requirement (20%) for physically effective roughage to enable healthy rumen development.

Nitrate poisoning - With the breaking rains after a prolonged dry we have seen some cases. Remember that this disease is seen more often when you have hungry animals, in a poorer body condition, given sudden access to a flush of green feed that may be high in nitrates. These are plants that are grown in highly fertilized areas, such as around yards or after urea fertiliser, and will also absorb more nitrates from the soil in the first flush of growth after a dry period. With sunny days they will utilize the nitrates for plant growth and become less dangerous. Some plant types, such as many summer weeds, our forage brassicas and oat, rye and sorghum crops are higher in nitrates. Fill animals with hay before introducing them to the crop, introduce for small periods of grazing first and watch closely for respiratory distress during the first 8 hours.

Pulpy Kidney - as soon as the flush of green pick kicked in we had some fatal cases of pulpy kidney in both sheep and cattle. One of the best things you can do to prepare your animals for the seasonal break and rapid change in diet is to give a minimum 5-in-1 vaccination pulpy kidney booster. 6-in-1 and 7-in-1 vaccines also protect against Pulpy Kidney as well as other diseases. In high risk situations such as these, a booster every 3 months is recommended.

Mannheimia Haemolytica - Due to the heatwave conditions earlier in the month we had some cases of respiratory disease in sheep feed lots. Prompt diagnosis via post mortem and effective treatment of affected sheep with appropriate antibiotics results in the best possible outcome.

Toxic weeds - With summer rain comes the growth of weeds and pasture plants that may be toxic. Beware panic species grasses and caltrops (cats head) for causing liver problems and photosensitization. Some older phalaris species can cause phalaris staggers and sudden death in sheep. If you are concerned it is best to talk to your district veterinarian about grazing management and prophylactic options.

Pinkeye has been causing issues in both cattle and sheep. Prompt treatment is recommended for both welfare and production reasons. See the article below for more treatment and prevention tips.

Grass tetany (hypomagnesemia) - With the short green pick and minimal roughage available this disease is a real risk. See the article below for more information and prevention options.

Barbers pole worm/second summer drench -it is a very important time to worm test your flock to assess the requirement for a second summer drench. In some properties the worm tests have shown no worms at all, but other properties have shown significant numbers of scour worms and barbers pole worm which could rapidly escalate into a problem if sheep are not drenched onto clean pastures in these warm wet conditions.

SOUTH COAST MOSQUITOS

Evelyn Walker District Veterinarian South Coast

The surplus rainfall and flood conditions in some areas of the South Coast have led to explosive populations of mosquitos, flies, midges and other biting insects. Not only is this a nuisance to people but can potentially have detrimental effects on livestock.

With increased insect activity, there is a greater risk of disease spread. These biting insects are capable of transmitting bacteria, protozoa and viruses from one animal to the next. In the Shoalhaven, we have already seen increased cases of pink eye and other bacterial related eye infections in cattle. A recent case of Theileria causing mortalities and abortions was also detected in the Illawarra region. High on the radar as we near Easter and autumn months is a viral disease called Three Day Sickness transmitted by biting insects.

Three Day Sickness (also known as Bovine ephemeral fever) causes fever, profound muscle weakness, lameness and stiffness in cattle. While cattle may recover in “three days,” stock at greatest risk are those that are late pregnant, lactating and heavily weighted animals such as cows and bulls.

NSW DPI and LLS District Veterinarians currently monitor the distribution of Three Day Sickness and other mosquito and midge borne viruses via sentinel herds throughout NSW. This is part of our contribution to the national arbovirus monitoring program (NAMP). Visit this site to see mapped out disease distributions https://www.animalhealthaustralia.com.au/what-we-do/disease-surveillance/national-arbovirus-monitoring-program/

In the South East, we regularly monitor herds located along the length of the South Coast and across to the Southern Highlands and Southern Tablelands. To date, there have been no detections of Three Day Sickness in these herds. It is recommended however that producers consider vaccinating at risk and/or valuable stock as a preventative. This vaccine is available from private veterinarians.

Regular herd application of tick, fly and lice treatments, at recommended retreatment intervals, is a good management practice doing this high risk season. Not only does this help from a disease minimization point of view, it reduces stress so stock can spend more time grazing rather than expending energy on swishing, stomping, rubbing or shaking their heads to remove biting insects.

Speak to your local District Veterinarian or private veterinarian if you have any questions or concerns regarding the risk of Three Day or other insect borne diseases in your cattle.

BEWARE OF THEILERIA RISKS IF INTRODUCING CATTLE

Evelyn Walker District Veterinarian South Coast

If you are considering buying or introducing cattle from non-coastal areas to your South Coast property, or from a coastal area to non-coastal one should be aware of Theileria and its risks and do some planning before the cattle arrive.

Theileriosis is a disease of cattle including beef and dairy caused by microscopic protozoa Theileria that attack the red blood cells. Theileria is primarily spread by biting ticks. But other biting insects such as flies, mosquitos and sucking lice have been implicated in disease spread.

There are many different protozoal species of Theileria. Theileria orientalis is the one associated with disease in Australia. The deadliest form of Theileria is not present in Australia.

Theileriais endemic on the South Coast of NSW from Wollongong to as far south as Bega. This means that the protozoa are widespread because of our conducive environment for ticks. Most of our cattle on the coast have developed some immunity to the disease as they have been naturally exposed to it. In local cattle, losses in productivity and deaths have generally been in young stock but adults (even if previously exposed) may also become affected. Homebred calves born in the warmer biting insect months are highly susceptible around 6-16 weeks of age due to their poorly developed immune system. Heavy tick burdens have not always been associated with disease. Previously exposed cattle may also succumb to theileriosis during lowered immunity especially around time of time of calving.

SinceTheileriaattacks red blood cells, a common feature is anaemia (pale pink and/or white appearance to the gums, eyes and vaginal mucus membranes). Occasionally, yellowing of these membranes may also be seen, due to the breakdown of the red blood cells. Other signs observed in affected animals may include lethargy and weakness, coughing, sunken eyes, drooling, sham drinking (put their nose in water, but fail to drink), poor appetite, drop in milk production, abortions, still births and deaths.

Theileriosis is diagnosed by a veterinarian using a combination of history, physical examination and diagnostic blood tests.

When introducing potentially non-exposed cattle into the South East, the following is recommended:

Avoid introducing new cattle in the warmer months when ticks and biting insects are most active.
Avoid introducing calves, late pregnant or lactating cattle. These classes of cattle are more vulnerable to illness and reproductive losses if exposed to Theileria.
If introducing susceptible stock, discuss with your local veterinarian the use of antibiotics for four weeks after arrival.
Introduce any heifers to the local area for a “settling in period” before joining.
Avoid paddocks where ticks may be more likely e.g. tall pastures and wooded areas.
Minimise tick and biting insect exposure by applying tick, fly and lice treatments regularly during high risk seasons. Beware if you are treating just once or twice with a short acting tick product, tick numbers in your paddock will not be substantially reduced. Follow recommended label claims for retreatment intervals to reduce parasite loads.
When introducing potentially exposed cattle from the coast to a non-coastal area, especially if mosquitos are active, you risk introducing this disease to your herd.

Speak to your local District Veterinarian if you have any questions or concerns regarding Theileria in your area.

THE RISK TO THE RESTOCKER

Lou Baskind District Veterinarian Palerang

Most areas of the South East have received, or are expecting to receive, a reasonable autumn break. There is also the prediction of warmer than average temperatures through autumn. So, we are expecting a fair amount of pasture growth through this autumn growing season.

As a result, many may be looking for opportunities to utilise this feed with restocking or trading. Demand for restockers has already jumped in the last few weeks and the market is likely to remain strong. Given the constraint of a strong market, you may be in a situation of “take what you can get” when looking to buy. While this approach may be necessary from a financial point of view, it is essential you manage the risks associated with this decision.

The impact of poor biosecurity can be extremely costly and have a long-lasting negative effect on your business. Before heading to the saleyard or buying online, refresh your understanding of the key principles of biosecurity. A good resource is farmbiosecurity.com.au which offers species specific tools and information. There is also a farm biosecurity app.

The key considerations are:

Read through the National Vendor Declaration that comes with the livestock. Wherever possible request an Animal Health Statement as well. Keep records of the origins of each group.
Buy from a trusted source.
Inspect animals before purchase and on arrival.
Isolate new stock well away from current stock for a period of 21 days, frequently checking for signs of parasites or disease. This should be in a ‘sacrifice’ area that will allow for later weed control or spelling.
Speak with a vet or advisor about vaccinating your current animals prior to introduction of new stock. Diseases such as leptospirosis, pestivirus, scabby mouth, vibrio (campylobacter) and Ovine Johnes disease have vaccination control options.
Speak with a vet or advisor about options for testing for disease in newly acquired stock prior to mixing them in with your current stock.
Treat all new animals for parasites while in quarantine. Guidelines for correct quarantine drenching of sheep and goats can be found on wormboss.com.au.

PINKEYE (INFECTIOUS BOVINE KERATOCONJUNCTIVITIS)

Iveta Martinsons (DVM4) Sydney University

Key Points:

Pinkeye is a bacterial infection of the eye which can be spread by flies and dust. Bright sunlight and physical irritation to the eye by wind and long grass will predispose cattle to pinkeye. Cattle that have not been previously exposed and young stock are most at risk particularly in spring and summer. Pinkeye is very painful and so treatment is advised for the welfare of the animal and to avoid production losses in affected animals. The earlier you treat affected animals the better.

Common Causes:

There are several bacteria that can cause pinkeye. The main one is Moraxella bovis. which has several strains.

Observations:

The signs can be broken up into stages.

Stage 1: First two days – Weeping eyes, red and swollen eye membranes, closed eyes. Both eyes may be affected. As this progresses the cornea becomes cloudy or white in one spot. Some may start to heal at this point, and this stage responds rapidly to treatment with eye ointment.

Stage 2: Over two weeks – In more severe cases the cloudy/white spot becomes bigger and the cornea can ulcerate. The eye will be swollen, the white spot may become yellow and then red. The cornea may rupture and causing the eye to shrink. This stage is best treated with eye ointment, patching +/- antibiotics.

Stage 3: Three to five weeks after infection – This is the recovery phase. The eye will be red and may have blood vessels across the eye. The eye will become a cloudy blue colour and may become clear, or a scar can develop and look like a blue/white spot. Cattle may become blind with this disease, and some cases may develop a non-healing ulcer.

Actions:

Topical antibiotics in the form of an eye ointment such as cloxacillin (Orbenin®) can be used to treat pinkeye. These must be purchased from a veterinarian. Both eyes should be treated. The antibiotic may need to be reapplied every 24 to 48 hours. In more severe cases veterinarians can also inject antibiotics and anti-inflammatories into the conjunctiva around the eye or treat with systemic antibiotics.
Glue-on eye patches should be used to minimise pain by preventing further irritation to the eye and keeping light, flies and dust out of the eye. Eye patches may be purchased from your veterinarian or from an online source.
If there is an abscess or a rupture, the eye it may need to be removed by a veterinarian.

Prevention:

Piligard® vaccine is available. However, it only covers 3 of the 7 strains of Moraxella bovis. It is beneficial in most cases but may not be protective in all outbreaks. Piliguard® is a one dose vaccine but needs to be given 3 to 6 weeks before the pinkeye season starts. It can be given to cattle as young as 2 weeks old. Therefore, this can be a consideration for vaccination at marking.
Managing other predisposing factors can reduce the risk of pinkeye.
1. Dust - avoid mustering in dusty condition, wet down dirt tracks when mustering if possible.
2. Flies - encouraging dung beetles, fly traps or pour-on repellents such as a synthetic pyrethroid which includes deltamethrin, will greatly reduce transmission of pink eye during high risk periods. As well as mustering early in the morning.
3. Eye trauma - thistle control, avoid grazing cattle with calves on spikey pastures.

References:

ARREST® EASY DOSE pour-on lice and fly treatment for cattle (Virbac Australia 2018): https://au.virbac.com/products/cattle-fly-lice/arrest-easy-dose-drench

Piliguard (Coopers Animal Health 2020): http://www.coopersanimalhealth.com.au/products/Piliguard

Pinkeye in Cattle (DPI 2007): http://www.dpi.nsw.gov.au/content/agriculture/livestock/health/images/information-by-species/cattle/pinkeye-cattle

GRASS TETANY (HYPOMAGNESAEMIA)

Iveta Martinsons (DVM4) Sydney University

Key Points:

Grass tetany is an important disease for cattle in the south east areas of Australia. Particularly for beef cattle grazing on improved pastures (grass dominant or cereal crops) on solodic, solodised soils or pastures that have received potash fertiliser in higher rainfall regions. Grass tetany is most commonly seen in freshly lactating cows around late winter and autumn but can also be see in younger stock on high risk crops.

Common Causes:

Low levels of magnesium in the blood is the main cause of grass tetany. The simple form is caused by a magnesium deficiency and a complex form caused by high potassium in the diet interfering with magnesium uptake from the rumen.

Observations:

Down cows, muscle twitching, staggers and aggression may be seen. Convulsions are a progression of this disease and death may follow soon after. Excitable behaviour changes in stock may indicate subclinical hypomagnesaemia.

Actions:

Calcium and magnesium injection. This in available at a 4 in 1 flow pack from rural stores or your veterinarian and can be given under the skin.
Feed supplementation with magnesium (60g/head/day Causmag® fed out on hay), looselicks (Salt:Lime:Causmag®; 1:1:1), magnesium lick blocks or oral magnesium boluses (Rumevite® Magnesium Capsule).

If treated early the prognosis can be good.

Prevention:

Move calving time to spring if possible.
Supplement cattle with magnesium (60g/head/day Causmag® fed out on hay), looselicks (Salt:Lime:Causmag®; 1:1:1), magnesium lick blocks or oral magnesium boluses (Rumevite® Magnesium Capsule).
Managing fibre intake. Feed more roughage to encourage rumination and salivation. This encourages magnesium absorption from the rumen.
Controlling potassium intake (managing fertiliser programs).
Minimize stress in grazing stock and recognise high risk situations.

References

Beef Cattle Health and Husbandry for the NSW North Coast (LLS North Coast 2016): https://northcoast.lls.nsw.gov.au/__data/assets/pdf_file/0011/685388/Beef-cattle-health-and-husbandry-for-the-nsw-north-coast.pdf

Grass Tetany in Cattle (DPI 2009): https://www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/health-and-disease/general/grass-tetany-cattle

Grass Tetany in Cattle – predicting its likelihood (DPI 2008):https://www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/health-and-disease/general/grass-tetany-predicting-likelihood

Grass Tetany in Cattle – treatment and prevention (DPI 2009): https://www.dpi.nsw.gov.au/animals-and-livestock/beef-cattle/health-and-disease/general/grass-tetany-treatment-prevention

Priority List of Endemic Diseases for the Red Meat Industries (GHD & MLA 2015): https://www.mla.com.au/Research-and-development/Search-RD-reports/RD-report-details/Animal-Health-and-Biosecurity/Priority-list-of-endemic-diseases-for-the-red-meat-industries/2895

Rumevite® Magnesium Capsules (Ridley n.d.): https://www.rumevite.com.au/product/rumevite-magnesium-capsules/

Contact Us

South East Local Land Services
District Veterinarians

Far South Coast

Mark Doyle
02 6491 7800

Goulburn