Broiler leg health: Must do more

By Poultry World staff

PROGRESS in the past decade in improving broiler leg health in the UK was not denied by anyone at a one-day workshop last month

But the industry clearly is expected to do more.

In this on-going scenario of seeking higher welfare standards for all food animals, lameness is the characteristic of broiler chickens that will go on getting the main attention in that sector, but who will pay when the measures increase costs?

Broiler growers among the delegates at Bristol Universitys School of Veterinary Science, Langford, could not see any bonuses coming their way for higher costs that would be incurred for some management factors that may reduce lameness in their birds.

They are not unwilling, but they cannot be uncompetitive.

Some simple elements of management in this complex picture would cost more, such as reduced stocking density, but there are others which could actually more than repay the investment by improving performance and efficiency.

If the return was not seen immediately, then it would be in the future.

That was the message from chairman Professor John McInerney of Exeter University when he opened the workshop – animal welfare was becoming a public value and increasingly people would pay for it.

But he warned that the industry could not afford to wait for higher prices or it could be in danger of turning consumers off chicken.

Hence it had to have a clear strategy to resolve the lameness issue if it was to sustain demand.

Causes and cures are gaining in complexity, as more is known about leg problems, for breeders and growers.

Work at Bristol has led to gait scores of 0 (sound) to 5 (should be culled) being developed subjectively by Dr Steve Kestin, who has refined the technique to such a degree that nobody has come up with anything better.

The causes were divided into two main categories by Andy Butterworth of Bristol, infectious and skeletal abnormalities.

Broadly these could be influenced by selection and management, to overcome poor conformation, bacterial infections, too rapid growth and insufficient activity.

The genetic aspects were dealt with by Dr Barry Thorp of leading breeders Aviagen, which during the past decade has put great emphasis on leg strength with many different selection measurements and removal of families with leg disorders from the breeding programme.

He quoted the success of reducing the incidence of tibial dyschondroplasia through early detection by the Lixiscope hand-held-X-ray-like device.

He also pointed out that breeders can only improve the condition where it is heritable and they were faced with selection for more traits every year, which were now governed by moral values of society and ethics as well as economics.

Veterinarian Dr Mark Pattison of Sun Valley Foods noted that genetic selection had reduced losses due to lameness up to 40 days of age and he saw scope for management making further gains by good ventilation, dry litter, at least 4 hours dark in every 24 and programmed feeding.

He suggested that there could be a place in future for a vaccine against staphylococci, the most common bacterial infection.

Going into more detail on some of these management factors, David Filmer of Flockman showed the cumulative benefits that could come from better management of nutrition on bird performance, welfare and health.

He demonstrated the knock-on effects of feeding whole wheat, which makes gizzards more active, leading to a reduction in coccidiosis, improved digestibility and beneficial changes to gut micro-flora.

These changes lead to reductions in nitrogen and water excretion, ammonia production and sticky litter.

Controlled feeding is the other nutritional key to bring widespread benefits, David claims.

He has shown that by step-down feeding of protein and controlling the birds intake, to achieve the desired growth curve, that more consistent live weights, lower mortality and reduced lameness can be achieved.

The important influence of high hygiene standards in minimising leg problems was stressed by Malcolm Pye of RL Consulting, who showed that this began as early as the hatching eggs, the elimination of floor eggs had reduced femoral head necrosis and metabolic problems in the subsequent broilers.

He stressed that production benefits could come from increased costs that addressed ways to reduce leg problems, one of which was to slow early growth rates.

In discussion of all of these factors, better drinking water hygiene was another that was acknowledged as beneficial and one where benefits could well outweigh costs.

Among this audience that represented the full range of interest and expertise – scientists, economists, welfarists, veterinarians, farmers, nutritionists, politicians – there was broad agreement that we have got to find practical solutions and they are there, it is just a matter of putting them into practice.

The incentive may not immediately be rewarding, but industry must heed the warning from John McInerney, who is a member of the Farm Animal Welfare Council (FAWC), which set off the national survey into broiler lameness with its 1992 report.

It is accepted that lameness matters to the bird, as shown by Dr Claire Weeks work at Bristol.

The nations most popular meat can only sustain that position in the long term if consumers are comfortable with the way it is produced.

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