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This month we farewell Emma our much loved Senior Large Nurse from her full time role.

Most of our clients, especially those with horses, know Emma well and we will all miss Emma's cheerful demeanour around the practice each day. She leaves large shoes to fill. Emma is pursuing her dream and has enrolled at University to further her career in the field of paramedics.

The good news is that she will stay with us in a casual role to keep her skills current so you will see her from time to time. 

Emma goodbye

Best of luck Emma with your studies

Contents of this newsletter

01  Easter Trading Hours

02  Pestivirus (BVDV) revisited

03  BVDV - the benefits of screening heifers for antibodies

04  More on worms

05  Time to review your equine first aid kit

01 Easter Trading Hours
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Easter falls the first weekend in April so we thought we should let you know our Easter Trading Hours in this March Newsletter. 

We are closed for the Public Holidays during this period except Easter Saturday when we will be open for normal Saturday hours. 

Good Friday - CLOSED

Easter Saturday - OPEN 8.30-12 midday

Easter Monday - CLOSED

We do have a vet on call for emergencies after hours . Please call 63618388. 

02 Pestivirus (BVDV) revisited
Pestivirus

PI calf (www.flockandherd.net.au)

Each year we work to educate our cattle clients about Pestivirus and the effect it can have in cattle herds. Vet Gabrielle Knight revisits this sometimes complex topic and reminds us why monitoring is so important.

What is pestivirus?

Pestivirus is a nasty disease that has the potential to cause some disastrous effects within your herd, including;

  • Poor conception rates
  • Abortions
  • Congenital calf abnormalities (birth defects)
  • Production of persistently infected animals
  • Respiratory disease
  • Increased rates of other disease

Infected animals may be transiently infected (have the disease for a short period and recover) or persistently infected (PI) meaning they remain carriers of the disease for life.

How is it spread?

Pestivirus is spread between animals in close contact, (primarily nose-nose) in areas of high density stocking (e.g. yarding, transport). Most bodily fluids can spread the disease (milk, urine, faeces, nasal secretions, foetal fluids, blood and semen).

Diagnosis

There are a number of diagnostic tests available for pestivirus. Samples include blood (serum), skin or hair. They may be performed individually or on pooled samples from numerous animals. We can determine the type of testing based on the aim of your investigation, your production system, herd management, biosecurity measures, cost and herd size.

Recognising a PI calf

Persistently infected calves can often be recognised as stunted, scruffy animals. They have a general ill-thrifty appearance and are susceptible to other infections. Rarely, these animals survive past 2 years of age. If you suspect a PI calf and are concerned about a pestivirus outbreak, please contact our clinic for testing.

What can you do if your herd is infected?

Ultimately the action plan will be determined in consultation with our vets. The options available include;

1.     Do nothing and allow the disease to run a natural course

  • Can be risky as transmission is unpredictable and often incomplete

2.     Use PI calves for auto-vaccination

  • Running a PI calf with small groups in yards can increase the rate of transmission
  • This should be conducted well before joining to minimise the risk of reproductive side effects of infection

3.     Establish a closed herd - Maintain thorough biosecurity and management practices to reduce the risk of introducing pestivirus

  • Test all animals to detect and eliminate PI animals
  • This option is risky on its own as it generates a naive herd
  • Generally it is conducted in conjunction with a vaccination program

4.     Implement a herd vaccination scheme

  • Complete - all heifers, cows and bulls vaccinated annually
  • Partial - only bulls and replacement heifers vaccinated

Conclusion

Pestivirus is a complicated disease process that has the potential to cause severe economic impacts (up to 25% losses) to your herd if it is not managed appropriately. As mention above, there are numerous options for management that can be tailored to suit your management practices. The best way to determine your herd’s pestivirus status is to consult with one of our vets for herd screening. Once the disease prevalence has been established they will be able to assist you in determining the best management protocol for your system. 

03 BVDV - the benefits of screening heifers for antibodies
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The embryo on the left is dying due to Pestivirus infection. The embryo on the right is normal.
Photo: Peter Kirkland

Bovine Viral Diarrhoea Virus (BVDV or Pestivirus) is very common in Australian cattle herds with around 90% of herds showing evidence of past infection. BVDV is capable of causing 25-50% production losses in recently infected herds and can decimate pregnancy rates. When cattle are infected with BVDV in the first month of pregnancy, it is likely the embryo will die. Further to this, it is estimated that 1% of the Australian cattle population is persistently infected (PI) with BVDV.

What is a PI?

A PI is a calf born with BVDV due to being infected with the virus as a foetus. Their immune system does not recognise the virus as foreign, and thus the animal is not capable of ever getting rid of the disease. PIs are the major source of infection in your herd.

Why and how do we screen replacement heifers?

Screening identifies the likelihood of a PI being among your replacement heifers.Heifers should be greater than 8 months old for screening and have had continuous contact with their herd mates for 2 months. 5% of the heifers, or at least 6 (whichever is more) are screened for antibodies.

  • If many heifers have antibodies to BVDV, then it they have been exposed to a PI - in this instance you find the PI
  • If heifers do not have antibodies to BVDV, then you should consider vaccination as an insurance policy

The ideal moment to do this for Autumn calving heifers is now. This gives you time to make decisions before the upcoming Autumn joining period.

04 More on worms
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Following on from our diatribe on worms in the previous newsletter, let's expand on the idea of increasing sheep resistance to worm disease by natural means.

Most animals are at risk of developing disease due to worms in the naïve and young. Lambs frequently fail to develop protective immunity to gastrointestinal nematodes. This results in direct losses from mortality and decreased production and indirect costs in the necessity for drenching post weaning.

Lamb weight is a function of birthweight, sex, genetics and growth rate. Nutrition and attention to the demands of the pregnant ewe are vitally important for a robust lamb of adequate birth weight. Diagnosis of twins, for example, by ultrasound pregnancy testing is an important management tool to help cope with the nutritional demands of the pregnant ewe. For the first 8 weeks of life, lamb growth rate is largely dependant on ewe nutrition and milk yield. After 8 weeks, pasture quality and availability to the lamb becomes increasingly important.

Under extensive grazing conditions, lambs frequently fail to reach the desirable target weight at weaning. Lambs should be approximately 45% of their adult weight at this time. Light lambs have limited fat reserves which may decrease their immunity to worms. Weaning itself has the potential to delay the development of immunity so it is critically important to wean lambs in adequate condition.

So, in summary, attention to ewe condition and nutrition and the quality of the lamb diet (including the possibility of early supplementation) are important ingredients in worm control on the farm. These measures, along with limiting the access of the naïve population to infected pastures, may reduce the need for non-strategic anthelmintic use and ultimately decrease the development of resistant worm populations on your farm.

05 Time to review your equine first aid kit
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There is nothing worse than being away from home, travelling or at a rally or competition, and needing some basic first aid for your horse. A first aid kit doesn’t need to be elaborate. Provided that you can apply some basic first aid yourself, this is often enough to get by until a vet is available if necessary.

Check that your first aid kit contains these essentials - and make sure everything is in working order:

  • Digital thermometer
  • Antiseptic wound cleaner such as Hibitane or Betadine
  • Clean leg wraps for emergencies. These should be separate to your everyday leg wraps
  • Gamgee, an absorbable padding for wounds to be placed under leg wraps
  • Self sticking bandage like Vetwrap to help keep bandages in place
  • Antiseptic cream or ointment like Septicide
  • Saline wound flush
  • Torch
  • Scissors
  • Notepad and pen
  • A record of your horse's resting heart rate, breathing rate and temperature for comparison when you think something might be wrong
  • Emergency contact details - like our phone number! You can call us if you're worried

Remember that a first aid kit should not become a medicine cupboard. If it becomes too large, it will get left behind rather than travelling with your horse.

The photos to the left show the same wound 6 weeks apart. It went on to heal well and the horse is back in action. All this was achieved with good cleaning, medication and bandages.