The health of a herd will be challenged during expansion which can either make or break the farm.

Smooth expansion can only be achieved when a farmer plans for financial, structural and herd health aspects in the business.

It is best to achieve a herd that is efficient and healthy before expansion, as increasing numbers in the midst of disease could be catastrophic.

It is also preferable to expand from within rather than purchasing from many outside sources.

This expansion from within will limit the introduction of new diseases into the herd, but farmers must consider that it is also important to prevent an existing disease from spreading within the herd.

Ventilation, housing and overcrowding challenges together with feed space shortage and labour stress, can all combine to act as tipping points in favour of clinical and subclinical disease.

Fertility has improved through the use of the EBI, but this improvement can be quashed if infectious diseases such as BVD, Leptospirosis or Neospora get a grip in the herd.

However, it is now virtually impossible to buy an animal Persistently Infected (PI) with BVD as tissue tagging has reduced this risk, the only avenue these animals can be purchased is through a PI foetus in a purchased pregnant heifer.

At present, 70% of herds have a Leptospirosis infection, and the only way to protect your herd from this infection is through the use of a vaccine. There is no argument other than to vaccinate!

The disease can be spread through the urine and results in abortion, a milk drop and it also poses risks to human health.

Salmonella also poses a risk, do not buy in Salmonella, your life will be hell after the introduction of this disease!

Expanding farms will have more calvings, more calves and more bugs during the spring time.

These extra numbers will likely mean an increase scours, navel and joint infections and pneumonia cases by the end of March.

Key questions for the expanding herd

Farmers considering expansion must first look at their system and identify how increasing cow numbers will impact on the disease and nutritional status of the herd.

Here are a few key questions farmers must answer before they consider increasing cow numbers.

Introducing Parasites
  • Will increased numbers change the grazing dynamic and increase the parasite pressure?
  • If calves or heifers are purchased have they previously been exposed to bowel or lungworm and what is their immune status to these parasites?
  • Could you be introducing fluke or rumen fluke in purchased animals?

Infectious Disease
  • How can you avoid the introduction of IBR, Salmonella or Leptospirosis into a herd that is relatively well settled?
  • What are the chances of buying an animal transiently infection (TI) with BVD? And what are the consequences?
  • What is the best way of buying animals free of Johnes disease?

Calf Disease
  • Will colostrum management suffer because of increased numbers?
  • Will Cryptosporidia be a squatting tenant in your calf house? Or will RSV spread through the lungs of all calves?

  • With increased cow numbers, have you adapted your paddock size and number to maximize grazing efficiency?
  • Will DMI (Dry Matter Intake) be limited by reduction in feed space?
  • Could heifers be bullied during competition for feed space and cubicles?

Other Health Issues
  • Is there a chance that new stock may introduce digital dermatitis or Mortellaro?
  • Is there a danger of introducing nasty mastitis bacteria by purchasing older cows?
  • Are your milking, calving and housing facilities sufficient to manage expansion without deterioration in hygiene and clinical and subclinical mastitis?

Frank O’Sullivan works in Patrick Farrelly & Partners Veterinary Practice in Co. Meath. The UCD graduate is also a member of Animal Health Ireland’s Technical Working Group and is the current Chair of the One Health Committee with Veterinary Ireland.