News & Articles
for Farmers
 

Newsletter April 2017


Neospora abortion in cattle.
Abortion is the production of a dead or weak calf which then dies within 270 days of insemination.  In the early stages (up to 4 months), most go undetected.  Most herds have an abortion rate of < 2% per year, but if this is over 5% it is likely there is a problem worth investigating. 
There are a series of well recognised agents known to cause abortion, however, anything which causes stress and/or a high temperature / severe infection in a pregnant cow can lead to that cow aborting.  So the list of causes is endless. 
All abortions in cattle need to be reported to the local animal health office who then decide if a statutory abortion investigation is needed.  This is focussed solely on brucellosis, additional investigation is an added cost but will be useful where its not just a one off.
Common causes of abortion are as follows: neospora, Leptospirosis, schmallenburg, brucella, IBR, BVD salmonella, and campylobacter. 
There are some unifectious causes too, of which mouldy feed (old silage) is one of the most common.  We will focus on Neospora caninum today as it is the most commonly diagnosed on lab submisstions – at about 26% of aborted foetal tissues. 
Neospora  can also be picked up by foxes, dogs, deer and rodents.   In dogs and foxes it is usually ingested when they eat infected meat.  They then shed the oocyts in their poo for a few weeks and this can be a source of infection for cows.  The parasite may then become latent in the dog but will no longer be a source of infection.  Occasionally older or immune suppressed dogs or puppies can show clinical signs but this is relatively rare.
 Neospora can be transmitted in one of two ways : firstly by ingestion of oocyts in feed or pasture contaminated by infected dog or fox or rodent poo, and secondly by vertical transmission.  This is probably more common in cattle herds, and means that a seropositive cow is likely transmit the infection to her calves.  This infection is quite often subclinical though so it doesn’t always cause abortion, but may do so at any time during the cows life.  It doesn’t cause infertility, but can affect the milk yield of the cow.  The infection always develops in mid to late stage pregnancy. 
Due to the high seroprevalence of this disease and the fact that there is no treatment or vaccination, eradicating it completely from a herd would be very difficult.  However where it is confirmed to be causing a problem the best ways to manage it are to minimise the chances of infection for instance by making sure dogs, foxes etc don’t have any access to cattle feed at all.  It might also be sensible to not keep or breed from heifers that are out of seropositive cows.  The important thing to remember here though is that there are many other causes of abortion in cattle and these drastic steps shouldn’t really need to be taken unless you are sure it is the neospora causing a lot of abortions.  Where cattle are very valuable, the vertical transmission can be interrupted by taking embryos out of a seropositive cow and implanting them into a seronegative recipient.
Neospora rarely causes abortion storms or outbreaks.  It tends to be more likely to cause a small number of abortions every year.  Those cows that are seropositive are at risk of aborting for the rest of their lives.  However where there is a high infectious load – for instance a lot of oocyst contamination of feed then numbers of abortions in a herd might be higher.


 


Previous Newsletters

March 2017
Pre-lambing nutrition:
Vaginal prolapse in ewes
Avian Influenza

January 2017
Bird Flu
Calf Scour

December 2016
Sudden deaths in lambs
Worms: Trichostrongylosis

CCN

Clostridial diseases and pasteurella pneumonia
Pneumonia in cattle

November 2016
Clostridial Considerations

September 2016
Abortion in sheep, its vaccination time!
Cattle Pneumonia

August 2016
Rumen bloat in cattle:
Frothy Bloat:

July 2016
Parasitic Gastroenteritis (Gut worms in sheep)
Coccidiosis
Joint ill: calves and lambs. 

June 2016
BVD sheep abortion and microchip reminder

April 2016
Congenital abnormalities in calves and lambs

March 2016
Calf Scour

February 2016
Lambing Special

January 2016
Pneumonia: the causes:

December 2015
A bit on cattle lameness: The common foot problems

November 2015

Anthrax
Brucellosis

October 2015
Pneumonia, and cattle shed design.

September 2015

Lungworm in cattle

August 2015
Sheep Farmers: wormer resistance

Bull Management in suckler herds

July 2015
Sheep diseases

Jaasiekte; OPA (Ovine, pulmonary adenocarcinoma)
CLA; Caseous Lymphadenitis

June 2015
the changing regulations for disease testing and control

May 2015
Joint –ill a reminder
Disbudding, dehorning and castrating


 

Strathbogie Veterinary Centre, 39,Gordon Street Huntly Aberdeenshire AB548EQ Tel: 01466792627 Fax: 01466 794962.