Replacement tests keep BVD away

Screening beef replacements for disease before they join the herd is helping a Hampshire suckler herd maintain its BVD-free status and prevent losses due to abortions or poor fertility.

As suckler herd owners recognise they can no longer carry passengers from one calving to the next, vet Jonathan Harwood of Stock1st, believes it is an ideal chance to establish a herd’s disease status, then take measures to protect it.

One of the simplest ways to do this – and achieve cost-effective results – is to focus on screening for BVD (bovine viral diarrhoea), he says.

This common cause of pregnancy loss is easy to test for and control.

But it is also particularly important for suckler herds which source dairy bred replacements, as 90% of dairy herds have been exposed to BVD.

“Most suckler herds seem to live with BVD and cyclical losses.

There are waves of infection every five years or so when up to 10% of pregnancies can be lost from failure to conceive, late abortions or the production of deformed calves.

Plus, carrier cows always have carrier calves,” he says.

“It costs from 6 to blood test an animal for BVD with vaccination costs at 4 a head the first year and 2 a year thereafter. But the cost of cows not getting back in-calf is high.”

Herds diagnosed as BVD-free can maintain their status by testing all bought-in stock to identify infected or carrier animals.

This option has been taken up by Mr Harwood’s client Nigel Powell, farm manager for Graham Mellstrom’s 283ha (700-acre) Walmer Farm at Bramshott, Liphook.

The farm’s 220-cow Simmental cross herd has just bought-in its first batch of heifers from a local farm and is awaiting blood test results.

Mr Powell switched from home-bred replacements to simplify management.

“Progeny are finished at 16-20 months and we need a minimum batch of 25 for transport, so we block calve in spring.

Previously we served 40 cows with a Simmental to get 20 heifers.

But then we had to sell Simmental cross bull calves.

I wanted to rear and sell only Angus cross animals on contract.

We sell at a deadweight of 280-300kg and earn a 30p/kg premium under a Waitrose contract.”

Fortunately, Mr Powell was able to source locally.

He found 29 Belgian Blue cross heifers bred in a local dairy herd and reared by a neighbour for an average £400 a head.

Aged 16-18 months they were the right age to breed to calve between March and May next year.

But conscious of the herd’s BVD-free status, established by Mr Harwood on a routine PD visit, Mr Powell put the heifers into quarantine when they arrived at the farm two months ago.

They were wormed with a pour-on product, which also helped get rid of any external parasites and stocked in a paddock across the road from other livestock to avoid any nose-to-nose contact.

Quarantine has also given him the chance to see whether the heifers were carrying any respiratory disease, ringworm or other skin disorders, or injuries.

After two months, the heifers were blood tested and fitted with a fly ear-tag and will stay in quarantine until test results are available.

If a carrier is identified, Mr Harwood will suggest it is removed from the group and fattened away from breeding stock to avoid risk of infection.

“Even if it is good news, I would advise a further month in quarantine before these heifers go in with breeding bulls and cows for peace of mind,” he says.

He also recommends Mr Powell maintains herd biosecurity rather than vaccinate the heifers.

This will involve securing boundaries so there are no break-ins or break-outs, allowing no stock to attend shows or markets, and disinfecting any humans or vehicles on their return.

With no other livestock on the unit, Mr Harwood also advises that no sheep are brought on, as they get Borders Disease, another form of BVD.

In future, Mr Powell plans to extend blood testing for any replacements, including the seven stock bulls.

He hopes to test stock pre-movement.

“We will be repeating the process and consider doing it at the farm we buy from, testing a few more than we need to in case there is a positive animal,” he says.