With up to 50,000 grandparent (GP) layer breeders and 142,500
parents on Hy-Line’s floors at any one time, UK breeder farms manager
Richard Beevis cannot afford any hiccups in production. Keeping birds
healthy and growing at a desired rate and uniformity are essential to
the success of his operation.
There’s also plenty of peer pressure — literally. Internal peer reports at Hy-Line compare his production efficiency against other company farms in France, Brazil and North America. “That keeps us motivated,” says Beevis, who is based at the company’s facility in Studley, Warwickshire.
For Beevis, the critical milestones in his operation are 7-day mortality, as well as the bodyweight and uniformity at 6 and 12 weeks.
“We’re typically targeting at least 80% uniformity,” he says. “We also try to get the bodyweight up at 12 weeks — about 100 grams higher than target — because they naturally go through a 5% to 12% weight loss when we move them from small colonies of 1,500 to 2,000 to colonies with 5,500.”
While Beevis and his veterinary consultant, Paul McMullin, MRCVS, need to keep their eyes on several intestinal and respiratory diseases in the GPs and parents, IB commands the most attention.
“There’s no question, we’re more conscious of IB than any other disease,” Beevis adds. “If left uncontrolled, IB could have a devastating impact on our operation. Fortunately, we’ve managed to stay a few steps ahead of the disease.”
Not just respiratory disease
When asked about the prevalence of IB, McMullin initially describes
the disease as the “chicken version of the common cold because, in essence, it will always be there in one form or another. There’s also a wide variety of strains, some more aggressive than others.”
But his common-cold analogy quickly ends there. “The trouble there is, comparing IB to a cold implies that IB is an upper respiratory problem, which it can be, but IB is able to infect a broad range of tissues," says McMullin, who has worked with the disease for 25 years in Brazil, Europe and Africa.
"In fact, the area where we can most readily demonstrate the presence of IB viruses for long periods after challenge is actually in the digestive tract, particularly those that are clustered in what's called the caecal tonsil. Kidneys can also be affected, as well as, of course, the reproductive tract. Calling the disease infectious bronchitis really is not giving it credit for everything that it can do.”
Uniform eggs essential
Not surprisingly, the biggest concern at an operation like Hy-Line — or
at least where the effect of IB is most visible — is its potential impact
on egg production. “If we were running tight on eggs and suddenly
had a large farm with a 5% or 8% drop in production from IB — eggs
that we were counting on to set for our customers — that would be a
big problem for us,” Beevis says.
Furthermore, the eggs that are produced by infected birds are usually poor quality, with thin shells. “We’re very strict in our criteria for selecting hatching eggs — an absolute minimum of 53 grams — so we can’t afford to have something like IB compromise our standards or chick quality,” Beevis says.
“With bronchitis,” he adds, “it’s not just the period of time that layer operations might see any production drop. It’s prior to the drop and post the drop as well. The egg drop might last only a couple of weeks, but IB could actually affect about 8 weeks of physical production — 2 or 3 weeks before the drop and another 2 or 3 weeks after the drop.”
Fortunately, Beevis says, they have yet to have a positive diagnosis for IB on any of their farms, but that doesn’t mean it hasn’t knocked on his door. According to McMullin, Hy-Line’s strategic approach to IB vaccination is designed to protect against a broad range of variants including the costly QX variant, which can attack the kidneys and central nervous systems of birds.
Hy-Line’s success managing IB is a good example of the phenomenon
known as Protectotype, he says. “Neither the Ma5 nor the 4/91 on
their own provide good immunity for the QX strain, but in practice,
when they’re used sequentially or sometimes in combination, they
have been shown to provide quite good protection,” McMullin adds.
The program starts on day 1, when chicks are vaccinated at the hatchery with Nobilis IB Ma5 and then at day 14 with Nobilis IB 4/91, both live vaccines. “Up to a couple of years ago, it was quite common to vaccinate broilers at day-old and not so common to vaccinate layers at day-old,” McMullin says. “That has changed, because clearly it's important with this particular QX strain, which is prone to cause damage to the oviduct if it occurs in early life.”
The Ma5 vaccine is used again at 5.5 weeks and 4/91 is repeated at 10 weeks. Birds are vaccinated at transfer — usually at 16 weeks — with Nobilis RT+IB Multi+ND+G (for GPs and breeders) or Nobilis RT+IB Multi+ND+EDS (for parents and pullets), inactivated vaccines that contain two IB serovars, plus avian pneumovirus, Newcastle disease and egg-drop syndrome viruses. At 18 weeks, they resume priming birds with live vaccines every 6 to 8 weeks and into lay.
“Technically, the local immunity achieved by the live vaccines we use in rearing will last up until 20 to 23 weeks of age,” McMullin says. “The problem, though, is that by 20 to 23 weeks flocks are coming into lay. That is a period of high physiological stress, so it's a very bad time for birds and they’re very susceptible to new infections.
"For that period of increased risk, after giving the inactivated usually on transfer, we generally recommend re-vaccinating with a live vaccine after about 7 days — after the flock has settled into the new accommodation, which also has its stresses," the veterinarian adds. "If we can avoid it, we don’t vaccinate for the following 10 weeks or until they are over peak production.”
Reflecting on their ability to fight off IB in the face of QX and other
variant strains, Beevis says, “The vaccines are doing their job, no doubt
about it. We see mild — very mild — IB challenges in most flocks
most years. But at the moment, it’s short-lived. IB comes and goes.
The QX variant is becoming more prevalent in the UK, yet we haven’t
changed our vaccination program for 12 months. I think that says
something about the vaccine products we’re using and when we’re
Beevis also credits Jonathan Perkins, a sales manager at MSD Animal Health, for the success of their IB-management program. “Jonathan has worked closely with us, providing training and auditing, which have been very useful,” Beevis says. “He’s conducted excellent workshops here for the people that actually handle our inactivated vaccine for us, as well as for the farm managers.
"These workshops keep everybody fresh," Beevis continues. "If people understand why they’re doing something, they’ll do a better job. If they understand the consequences on a rearing farm as to why they need to administer an IB spray vaccination correctly, and if they understand the consequences of what happens if they don’t perhaps toe the line, then they’ll focus more.”
Country Fresh Pullets
While consistency and uniformity might be the hallmarks of a
layer-breeder producer, diversity and customization are the bywords
at an operation like Country Fresh Pullets, Shropshire — the largest
pullet rearer in the UK.
“We are totally customer-driven,” says Richard Parsons, production manager. “We don’t advertise breeds. Whatever the customer wants, we will rear. We’ve got the space. Last year we reared in excess of 7 million.”
Country Fresh currently rears layers from Hy-Line, Lohmann, Goldline, Hendrix Genetics and at least five other breeding companies. “We also do some Columbia Blacktails. And we also do a few what we call specials — exotic things that lay blue eggs and brown eggs.”
Country Fresh has 34 contract and 15 company-owned farms ranging in capacity from 6,000 to 200,000 birds. Farms take delivery of day-old chicks and then rear them to week 16. During that time, birds are typically primed and boostered with vaccines 16 or 17 times, against a wide assortment of poultry diseases.
“Obviously, vaccination is critical to our own production, but it’s even
more critical to the end-user, our customer,” Parsons says. “We want
repeat customers. So it’s important that our product leaves us with
the highest level of protection possible.”
Parsons lists Marek’s and Gumboro as the most feared diseases in their rearing operations, but his radar is firmly fixed on IB and its changing variants.
“We don’t tend to see too many IBs in a rearing environment. It’s not something that would affect us here today,” he says. “But obviously, for our customers, it’s critical that the birds are protected because there’s a lot of bronchitis out there. If our birds get an early infection with an IB QX, for instance, then the repercussions to the lay of our customer could be severe. So basically, if IB is a concern for them, it’s a massive concern for us. We have to provide a bird that’s been given the maximum IB protection available.”
For that reason, Parsons continues, they were advised last year to introduce Nobilis IB Ma5 at day-old, which is administered in the hatchery, and then follow up with Nobilis IB 4/91 at 14 days, both live vaccines.
“Our vets, as well as the veterinary surgeons of our customers, tell us that’s the best cross-protection available against QX, which can be devastating in the laying environment,” Parsons reports. “And theoretically, they also cross-protect against IB 755 (Italian 02) and other variants. The tricky thing is, the variants change all the time. You never know what to expect. We do serology at 12 or 13 weeks to make sure the priming vaccines are doing their job. But in general, the vast number of IBs that we’re seeing are related to 793B (of the same Protectotype as 4/91) or QX."
No standard program
The Ma5 vaccine is administered again at day 35, this time as Nobilis
Ma5+ Clone ND, which includes protection against Newcastle disease,
followed by another IB primer vaccine at day 84 to protect against the
IB H120 and IB D274 variants. At transfer, birds are vaccinated with the
inactivated combination vaccine Nobilis RT+IB Multi+ND+EDS “for
extra IB barriers.”
“We’ve got something like 67 vaccination programs currently in our database that we use all the time,” Parsons says. “There’s no such thing as a standard program, but broad IB protection is something our customers need to have.”
When Parsons joined Country Fresh 21 years ago, the company predominately used one breed of bird. "They pretty much received all of the same vaccines and that was it,” he recalls. “Now, we have about 10 different breeds out there, all of which will be transferred to different types of farms, in different environments with different lighting and so on. We have to segregate houses by breeds, lighting and vaccination programs.”
More than anything, Parsons says, the industry's switch to free-range production — now practiced by about 70 percent of his customers — has increased flock exposure to diseases.
'Blown out of the water'
“When birds were in cages, they were in a controlled environment
and probably subjected to less stress,” he says. “Birds like routine;
they love routine. But when you put birds into a free-range situation,
routine is blown out of the water. Birds are being let outside, so
they’re exposed to more disease — not just the IBs, but farm-specific
problems. If people are raising pigs and sheep in the range area, for
example, erysipelas and E. coli can be a concern. The demand for
more complex vaccination programs is being driven by free range.”
To minimize stress on its birds, Country Fresh works under two auditing bodies — Freedom Food, the farm assurance and labeling initiative monitored by the Royal Society for the Prevention of Cruelty to Animals, and the British Lion Code of Practice administered by the British Egg Industry Council. Many of their farms now have slatted-perch flooring areas, which helps maximize production per square meter while allowing birds to be more mobile and develop better leg strength, Parsons says.
“That's a huge advantage for the free-range layer,” he adds. “The stronger the bird is, the better it will withstand the rigors of IB and other disease challenges.”