Problem solving pays off

Leics producer Alan Smith is investing in his business this summer with a new 40-point rotary parlour and plans to go up to 400 cows. He is also protecting his investment in top Holstein genetics by vaccinating heifers against IBR.

Like many producers seeking to reduce the workload at home while maximising output from a family farm, Mr Smith contracted out part of the heifer rearing enterprise three years ago. Youngstock are now sent to Cheshire at 12 months of age, returning ready to calve down and join the 300-cow Bumblebee Hall herd at Sharnford. But it soon became obvious these young animals weren’t performing as they should.

“We were getting up to 50 litres/day in younger cows, but then they got flu-like symptoms, lost their milk for a week and when they started milking again were only giving 40 litres/day,” says Mr Smith, who runs the farm with his father Leonard and brother Ian. “They did this several times in a lactation and the more stale they were, the poorer the recovery in milk yield seemed to be.”

It wasn’t just heifers. For some time, the odd cow would abort while others would have severe flu, or pneumonia, and die suddenly. “They would have a runny nose, be off their feed and sick, with high temperatures. With such high yielding cows – our lactation average is now 10,811kg – we couldn’t afford to put up with this level of disease.

“We had noticed our rolling 12-month average yield dropping as we weren’t getting cows back in-calf. It went from 9,800kg to 8,900kg, not a great amount every month, but it soon starts to show up over a year. Our calving interval was also slipping, from 415 days to 450 days over a 15-month period. Also, the high level of infection circulating was playing havoc with cell counts, they were going through the roof and down again for no apparent reason.”

A change to a new vet practice set things in motion. As part of developing a proactive health plan, prompted by the new practice, The Park Veterinary Group, Mr Smith had bulk milk samples tested for IBR, BVD and leptospirosis. The results surprised his vet, Peter Orpin . While the herd was positive for IBR, it was free of both BVD and leptospirosis.

“Using the results, we drew up an action plan with Peter. We tested milk from first and second lactation animals and they were quite bad with many cows showing high IBR antibody levels. Then we blood tested 6-15 month old heifers and found they were clear,” says Mr Smith.

“Potentially heifers were picking up the IBR infection when they went away. That said, we also expanded the herd rapidly in 1996 from 120 cows with bought-in stock, so IBR could have come from any source,” he adds.

Mr Orpin explains that although the herd was infected, because calves and heifers are reared separately, they remained IBR negative. This meant that when heifers joined the herd, they were naïve and highly susceptible to infection at a time of great stress. “I can’t think of a worse time to get IBR than after calving,” he says.

“Heifers reared away became infected as soon as they return to the unit. So we need to make sure they have the same immune status as the cows to withstand any IBR infection that is circulating. Vaccination damps down virus excretion and also boosts immunity.”

Every animal was duly vaccinated in January this year with Bovilis® IBR: a total of 400 head. Heifers were done before they went away and, for added protection, were also vaccinated against leptospirosis and BVD. Baby calves, however, were put on a programme of routine blood tests to monitor their IBR-free status. Bulk milk levels are now tested quarterly for IBR, BVD and leptospirosis.

Since vaccination, Mr Smith reports no abortions and says he can’t believe the difference it’s made. “We had a third calver who aborted twin bulls in November last year and she was struggling to give 10-15 litres/day. After vaccination, she’s gone up to 51 litres/day; that tells its own story. Cows that have calved since vaccination have achieved record peak yields, they are milking so well: 60 litres/day with 45-50 litres from heifers. We’ve done quite a bit of flushing as well and had fantastic results: 33 grade A embryos from one cow in three ET flushes.”

A DCAB diet introduced for dry cows has also played its part, he adds. With cows such as Bressingham Storm Rachael EX92 producing a third lactation of 19,103kg at 4.05% fat and 3.29% protein, and Bumblebee Hall Outside Lucy, VG87 2 year old, a first 305-day lactation of 14,801kg, Mr Smith is understandably keen to protect his income. He accepts there are health risks rearing stock off-farm, but it takes pressure off the family at harvest time and stock return well-grown. From now on, as part of the veterinary health plan, bought-in cows will be sourced from herds with a known health status and either blood tested or given an IBR booster vaccination before joining the herd.

“The clinical signs of IBR are very varied which, coupled with the fact that recurrence of the disease is brought on by times of stress such as calving, moving or even just the weather suddenly turning cold, is incredibly hard to manage without vet input and vaccination. My advice to others is, if you see these flu-like symptoms, get testing. IBR can be a small problem, but soon accelerates and it’s only a small cost to put right. Vaccination is about £3/cow and we’ve spent £1,000. What’s that compared with the cost of a commercial cow these days?”

IBR in the rest of Europe is classed as a disease to eradicate, whereas in the UK it’s often ignored and reacted to. However, vet Peter Orpin of The Park Veterinary Group, Leics believes vets and farmers need to move towards a clear plan of action to manage and control it. “But the key is to do so economically,” he adds.

The problem is the impact of this disease is hard to quantify as it can be hard to spot. “Some herds may see cows that are just a bit under the weather which may be explained away for another reason. It’s possible smaller herds may not see such extreme symptoms, or that heifers may just look off-colour because they are not under the stress of milking,” he explains.

However, with some 80% of herds in the practice testing positive for IBR it is a common problem which is draining production and profits. “In our experience, cows with IBR infections are more likely to have other problems such as mastitis. In breeding herds, there is no point in embryo transfer work if the results end as abortions. Value of health control, therefore, depends on the value of stock. Unfortunately, most people put up with endemic diseases.”

Mr Orpin suggests the starting point is to test bulk milk samples to establish whether a herd is infected with IBR or not by using Intervet’s subsidised DairyCheck screening service.  Then look at whether it is causing a problem. “If the bulk milk test is positive, the next step is to look at first lactation heifers and some youngsters. The disease becomes more evident in animals under stress as they excrete the virus. This includes those producing more milk, under housing stress and potentially energy deficient.”