Animal Health Update
November 2018
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Local disease watch
Alex Stephens – District Vet for Yass, South East Local Land Services
The last 4 weeks have seen a swift transformation from spring into early summer with most areas drying off without a lot of spare dry feed. Murphy’s law would have it that this spring the District Vet team still saw some occasional cases of bloat and pulpy kidney, but these cases were mostly over before they had begun. Although queries about the ultilisation of failed crops and rapid feed changes has still made the 5 in 1 pulpy kidney booster our favourite recommendation.
Many producers are looking at the summer months ahead and continuing to destock and planning for options such as early weaning. LLS has been running producer workshops looking at the use of Stockplan to cost different destocking options relative to the cost of feeding.
Disease wise District Vets have been investigating cases of abortion in goats and cattle and poorer lamb marking to scanning percentages in sheep. Seasonal conditions certainly contribute to these disappointing results but it is worth ruling out diseases such as Neospora, Leptospirosis, Vibriosis and Pestivirus in cattle and Campylobacter as a contributor in sheep, especially if results are worse in the maidens.
The tough seasonal conditions have also contributed to higher lice numbers and treatment enquiries in both cattle and sheep due to both nutritional stress and increased comingling.
Blood tests have also confirmed fluke as a cause in a couple of cases of ill thrift. District Vets in all areas have continued to support producers, police and the RSPCA wherever the welfare of stock has become a concern. In some of these cases producers have been feeding stock but the feed tests on the fodder have shown extremely disappointing results.
Energy and protein levels have been far below expected levels. Feed test bags are available from all LLS offices, the cost of a test is around $70 and results are back within a week. This provides vital information for the formation of rations.
Worm watch
Lou Baskind – District Vet for Palerang, South East Local Land Services
While spring storms do a lot to lift our spirits (and the stock seem a little more contented too) there are worm risks associated with this period of increased moisture and temperatures.
With the average daily temperatures on the increase and a little bit of moisture around from storms, internal parasites are likely to become active, particularly if barbers pole worm is present on the property.
The ‘first summer drench’ is an important strategic drench, given as pastures dry off at the start of summer and as sheep are moved to a new pasture.
Drought, and drought feeding, contribute to factors that favour worms, including:
- Short pasture: Most worm larvae occupy the first 5cm of pasture, while above 15cm there are almost no worm larvae. With our current short pastures, many stock are grazing right in the “worm zone”.
- Increased grazing pressure on “flukey” areas such as springs, creeks and seepages. Tactical grazing strategies are difficult to implement when options for feed are so limited.
- Condition of livestock: Nutrition and condition have a major impact on resistance and resilience to worms. Energy and protein are essential for resilience and protein, in particular, has an effect on resistance. Micronutrient deficiencies also contribute to susceptibility to worms.
- Stock age and stage of gestation: Lactating and young stock have lower immunity to worms.
All these factors combined have the potential for parasite levels to escalate. Costs associated with internal parasites include deaths and significant production losses from weight loss and scours.
Some strategies to manage the worm burden at this point in time include:
Sheep
Start doing your faecal egg counts (FEC) now as you plan for the first summer drench. The kits are available from the Local Land Services offices or you can order them from the State Veterinary Diagnostic Laboratory on 1800 675 623 or at https://www.dpi.nsw.gov.au/about-us/services/laboratory-services/kits-and-media/order-sample-collection-kits.
For your first FEC we recommend you choose Worm Test Gold ($61) with Worm Typing ($22). Don’t forget to request an additional Fluke test as well - costs can be reduced by choosing the Fluke Bulk 2 ($55). Remember to contact your District Vet to assist with interpretation of results.
Cattle
Don’t forget your routine drenches for weaners and yearling cattle. This is probably a year for a December drench for yearlings, especially if you have been unable to prepare worm-safe pastures. Always drench calves at weaning and then at intervals throughout their first year. For intestinal worms, adult cattle over 24 months should not need drenching unless they show signs of being “wormy” such as scouring or loss of condition or if condition is very poor due to nutritional stress. Contact your DV or private vet to discuss whether poor condition could be due to internal parasites in your adult cattle.
Fluke
If you know you have a fluke problem then use of strategic drenches in April and August help to prevent the build-up of fluke numbers over the summer. Summer drenches may also be required in December and February if strategic control has not been undertaken or effective enough. Over summer fluke problems become obvious as bottle jaw, stock doing poorly, or deaths. These symptoms should be investigated. If you don’t know if you have a fluke problem then a fluke surveillance program is a great idea. This involves checking for fluke at least 3 times yearly using any of the methods of faecal egg counts blood tests or abattoir surveillance. Contact your DV or private vet to discuss.
Integrated Approach
As always with parasite control, use an integrated management approach to reduce reliance on chemicals and slow the resistance to the chemicals currently available. Drenching is only one part of internal parasite management. See the Wormboss site for detailed information on tools such as grazing management, drench combinations and drench rotations at www.wormboss.com.au/tests-tools/management-tools.php
The Natural Resource Management (NRM) team at Local Land Services have funding available for fencing creek lines, alternate water supply and paddock subdivision which can all be utilised in an integrated management approach to worms and fluke.
Contact the Local Land Services offices to see if you fit into the catchment area and criteria for these projects.
Cattle Lice
Lou Baskind – District Vet for Palerang, South East Local Land Services
Plenty of cattle herds in the Braidwood region have been affected by cattle lice over the past few months. Lice cause cattle to rub, and the resulting bare patches of skin are usually seen on the neck, shoulders and rump.
Lice are small, flat-bodied, wingless insects with legs modified for gripping hairs. Lice species are specific to their host, which means cattle lice are not the same as sheep lice, or human lice. Lice are spread by direct contact between cattle and don’t survive very long if they drop off into the environment. Female lice lay eggs (called nits) which they cement to the hair shafts. After one to three weeks the egg hatches to a nymph stage, which feeds and moults several times to develop into an adult. The whole lifecycle can take as little as three weeks. Even though they are specific to their host, they can sometimes “hitch a ride” on another species, but they will not feed or complete their lifecycle on the wrong host.
Lice can be categorised into two types, biting lice and sucking lice. The biting louse, which feeds on skin material at the base of hairs, is reddish-brown and up to 2mm long. The sucking louse feeds on blood. There are several different species of sucking louse which range from 1.2mm - 5mm in length.
Lice itch and distress cattle causing them to groom and to rub against fence posts, trees and other objects. The result is loss of hair and heavy rubbing can cause open sores.
Lice do not like hot skin or direct sunlight and so are usually more active in autumn and winter. Egg laying activity and egg survival is reduced when temperatures increase. Small numbers will survive the summer by sheltering under the tail or jaw.
Well-fed healthy cattle do not tend to develop heavy lice burdens. Poor condition cattle with poor energy and protein diets are the worst affected because adequate dietary energy and protein are required to maintain the immune system. One can assume a herd with heavy lice infestation is also at risk of internal parasites and other diseases.
It is a matter of debate whether lice directly affect growth and production, but discomfort and distress do have welfare implications. When cattle are in poor condition, lice can add to their overall depletion and worsen un-thriftiness.
Before attempting to treat for lice, firstly confirm that lice are present by examining the skin. There are other conditions that can cause hair loss or rubbing, such as moulting of the winter coat, or the fungal infection called ringworm. Carefully inspect the hair and skin in good light (wearing your reading glasses if required). Often the nits are easier to see than the lice. Biting lice will move when the hair is parted, while sucking lice may be clustered in patches that look like scabs. On closer inspection these “scabs” are a mix of eggs, adults and nymphs.
Various chemical treatments are available for lice control. These chemicals will also have impacts on internal worms so think very carefully about how these will fit into your strategic drench program to manage drench resistance. If cattle need to be drenched for internal worms, an oral worm drench that will also control lice is recommended. Oral drenches that include a “mectin” (ML) product will have activity against lice.
If cattle do not require a worm drench, then an “external parasite” product is recommended. These include the “methrin” group of chemicals, or the products diazinon or diflubenzuron. These treatments are applied as pour-ons or sprays. Most insecticides are not effective against the lice egg (nit) because it is protected by a tough outer layer. As such, a second treatment may be required 3 weeks after the first.
All of the chemicals used for lice control have the potential to be toxic to humans and other animals. Read the label and follow the safety directions precisely during preparation, application and disposal. Also be aware of the withholding periods and export slaughter intervals.
Another approach used by some is to apply yellow dusting sulphur along the backline. This treatment gives relief to the cattle by knocking back some of the lice population, but is unlikely to eliminate lice and frequent re-application may be necessary. Dusting sulphur is a serious eye irritant and can be a skin irritant so wear protective gloves, protective clothing, and eye protection if using it.
Increasing summer temperatures should put a stop to lice breeding, but if heavy burdens are causing distress and body condition is poor, a chemical treatment for lice should be considered.
Beware of giving livestock unusual feed
Petrea Wait, District Vet for the Monaro, South East Local Land Services
With the drought affecting much of NSW, farmers are sourcing feeds that may not normally be fed to livestock. There have been reports of stock being fed rations containing products as diverse as tree trimmings, fruit and vegetables, sawdust and used cooking oil.
When feeding stock material that is not normally considered as stock feed care needs to be taken to ensure that it does not contain prohibited or restricted substances or chemical residues.
For ruminant animals, prohibited substances include those that contain or are produced from tissue, blood or feathers derived from the carcass of an animal, although milk products, tallow and gelatin are exempt. For pigs, prohibited substances include any product from a mammal (including tissue or blood) except if authorised. The feeding of these products is an offence under the Biosecurity Act 2015 with a maximum penalty of $11,000.
Chemical residues should also be avoided by requesting a Commodity Vendor Declaration (CVD) with any feed sourced for livestock. If the material being fed has not been produced specifically as stock feed and does not have a CVD the product should be withheld from the stock for 60 days prior to sale for slaughter, or a 'yes' answer must be given on the National Vendor Declaration (NVD) to the questions regarding the feeding of by-products or materials within a withholding period.
For more information you can access the Primefact "Dangers in feeding waste material to livestock" (link below), or contact your local District Veterinarian.