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Cases

A split calving dairy herd with 500 autumn cows in peak lactation


Individual Sick Cow
A 7 year old jersey cow was slow out of the paddock and struggled to get to the shed. She was off her milk and lagging behind the rest of the herd the day before.

On examination she was unable to walk any distance without having to lay down/collapse. She was found to have pale jaundice membranes around her eyes and in her vulva. The primary causes of this would be liver failure or a breakdown of the cow’s red blood cells. The cow had a rapid heart rate (150) and was breathing very quickly. Her temperature was within normal limits and her rumen was turning over slightly slower than normal. She also had mucus casts (slimy faeces which contain the lining of the intestine).

With the signs seen at the clinical exam it was suspected that the animal had Theileriosis. Blood samples were taken and sent to the lab to look at how much blood had been lost and if the parasite could be seen. The other explanation was liver failure where the prognosis at the severity seen would ultimately have been death. The animal was given oxytetracycline antibiotic (Engemycin®) into the vein while the blood was rushed to the lab.
The blood result came back within three hours and we had confirmation of the veterinarians’ suspicions. After consulting with the client it was decided to carry out a blood transfusion on the affected animal. 4 litres of blood was collected from a large healthy cow and then transfused into the affected animal who was still down. The improvement was instant.
 
She recovered well and returned to milk. We suspect this farm has avoided a large outbreak due to the fact they already have good management plans in place for at risk cows, such as those with a low body condition score i.e. dropped to once a day milking.
   
The first and largest outbreak in the southern area of our practice

Large herd outbreak
This is a split calving herd with 160 autumn calvers. Post calving, several animals were showing the following clinical signs:
  • Lethargy
  • Weak
  • Severe rapid weight loss
  • Poor milk production
  • Mortality
The freshly calved cows were lethargic and over the space of 48 hours rapidly lost condition, their udders turned pale and they began to lag behind the other stock. The animals were treated with Eprinex® at first as the farmer suspected that worms could be a factor in the blood loss and ill-thrift. This unfortunately had no effect and veterinary involvement was sought when one of the animals went down in a paddock following afternoon milking.

It was evident from the beginning that the animals were all anaemic, the down cow died while the vet was walking to examine it. With an outbreak such as this a colleague was called to help out, as all the groups on farm needed to be assessed and a thorough history would be needed.

The post mortem showed that the whole carcass was severely jaundiced. The liver was normal size and texture but was an ochre colour and some lymph nodes were slightly enlarged. Otherwise the animal was normal.
 
Blood samples were collected from ten fresh cows in the shed and several other recently calved animals were examined. They had rapid heart rates, rapid breathing and one was found to have a raised temperature. They were treated with oxytetracycline antibiotic (Bivatop®).

The dry cows were looked at in their paddock and all the animals were in good condition and were not showing any of the signs the fresh calved group were.

Multiple samples were taken off and looked at that night or sent to the lab the following morning.
As the results came back from the lab it became evident that Theileria was a major factor in the outbreak. As it had previously only been suggested that it only occurs in animals which have been suppressed by another condition, further tests were suggested. The Ministry for Primary Industries was also informed and funded further testing into the outbreak.

Any thin cows prior to calving were given a dose of Engemycin® * antibiotic to try to lower the parasite numbers. Blood transfusions were also performed on several clinical cases.

As this was one of the first cases seen in the area and with such a large number of animals affected it was a difficult case to work through for everyone involved. During the calving period it became evident that certain treatment protocols worked while others didn’t seem to be as effective.

Animals affected with Theileriosis should be given a blood transfusion as oxytetracycline alone does very little to stop them from becoming dry.

Administering oxytetracycline pre-calving seems to level the playing field in terms of at-risk animals showing similar levels of parasite and anaemia as untreated good conditioned animals.

Ultimately about 10% of the herd ended up going dry. There were no further deaths once the diagnosis was reached. The source of the infection was identified and herd management plans were implemented to reduce further exposure of dry stock to infectious ticks. From the lab results it appears that almost 100% of the animals in the autumn herd had been infected at the run off, the young stock there were also infected while away from home.
 
As there is currently licensed treatment or vaccine to control Theileria, creating a management plan to reduce exposure of susceptible animals to ticks should therefore be high on the list of priorities. Franklin Vets have been at the forefront in developing strategies for control and treatment of this disease over the last 18 months. Our clinicians have talked at veterinary conferences and training days to raise awareness and the level of skills required to treat this disease.

Tick control is important during risk periods. This is commonly mid-August to mid-March, but as long as the mean air temperature is above 7˚C ticks will be active to some degree. Tick control is also important during periods of stress, for example calving and peak milk production.
We recommend Flumethrin for tick control;
Controls all life stages of ticks
Nil withhold period for meat or milk
Protects for 3-6 weeks
Python® Ear Tags (NB: only an aid to control ticks)
Aids in control of ticks on cattle
Two tags, one in each ear
Aids in control for at least six weeks
Nil milk and meat withhold
These are the only two products licensed in New Zealand for tick control. There are several other products used around the world, many of which are available here and used as part of a routine worm and lice control programme.
Pasture management
Try to identify high risk areas and ear mark them for preserved forage and maize during risk periods. High risk regions would be paddocks with or next to trees, scrub and rough grazing (i.e. around drains). Wildlife also poses a risk as small mammals and birds can also act as hosts for ticks.
 
Other animals (hosts) on the farm
Dogs and cats  Bravecto oral tablet for dogs, Frontline® Plus spot-on or spray, Seresto® Tick collar
Horses     Python® ear tags, Permoxin® rinse or
Insect repellent collar
Deer         Python® ear tags


When implementing a tick control program on your property it is worthwhile consulting your Franklin Vets veterinarian. It may be possible to integrate tick control into your existing parasite control program as some commonly used products may confer protection against ticks.

Franklin Vets have developed over the past year a number of helpful tools for farmers who are concerned about Theileria. 

There are still an awful lot of unanswered questions about this disease. The industry is working together to reduce its effects on the beef and dairy sectors and MPI continue to invest resources in research to better understand the disease. For this reason publications can become quickly outdated, if you have any concerns then your first port of call should be to contact a vet or refer to the MPI website for the most up-to-date information.