Tunnel Ventilation for Commercial Turkeys

When re-designing a ventilation system, it is important to consider both the extremes of hot weather in the summer and minimum ventilation during the winter, according to Dr John Menges of Hybrid Turkeys in Canada,

"Energy efficiency is the name of the game in the turkey business these days," he stressed, "whether it's feed, electricity or propane because all these costs are going up."

He explained that while almost all broilers in North America are now kept in tunnel-ventilated buildings, this trend has only been adopted more recently for turkeys. It has the advantages of improving performance during hot weather as well as lowering mortality from heat stress, he said, adding that these aspects are especially important as turkeys are now reared to heavier weights (to over 19kg) and feed becomes more expensive.

Dr Menges went on to compare the differences between conventional and tunnel ventilation, particularly emphasising the benefits of tunnels during hot weather. He covered the principles for designing a typical tunnel system and how evaporative cooling can be used to reduce the temperature further.

* "Energy efficiency is the name of the game in the turkey business these days"

He stressed the importance of using the environmental controls correctly, as young turkeys are particularly susceptible to high air speeds and excessive evaporative cooling before they are fully feathered. If they become chilled, they will tend to huddle and neither eat not drink. On the other hand, the performance of older turkeys suffers if the tunnel fans are not used early enough.

Tunnel ventilation can be an effective tool to maintain animal performance and sound animal welfare during hot weather, Dr Menges concluded.

He added: "Managers must look to the cost of constructing new turkey barns or converting existing facilities as well as the cost of maintaining and powering these systems.

"As with any system, if it is managed poorly and young turkeys are chilled or older birds are not cooled early enough, tunnel ventilation will not perform to expectations," he warned.

"However, as we continue to improve the efficiency of our production systems by raising heavier and more efficient turkeys, we must also examine our facilities and make the necessary improvements to accommodate these additional pressures," Dr Menges concluded.

Using Diet to Improve Turkey Litter Condition

* "Feeding diets with a lower crude protein content improved litter condition for growing turkeys"

Dr Vasil Pirgozliev of Scottish Agricultural Colleges (SAC) presented a study on the effects of turkey diet formulation on litter quality. From the results, he concluded that feeding diets with a lower crude protein content or with a higher ratio of apparent metabolisable energy to crude protein (AME:CP) improved litter condition for growing turkeys.

There is little published information on litter quality in turkeys, Dr Pirgozliev explained, although it can have important impacts on both welfare and carcass quality. 'Bad' litter could be defined as that exceeding 25 per cent moisture, he added.

The researchers used five dietary treatments, containing 77, 85, 100, 110 or 130 per cent of the crude protein recommended for the breed, BUT 8 birds.

Dr Pirgozliev and his co-authors found there was a linear relationship between crude protein level and litter moisture, litter ammonia and litter score. Hock burns and pododermatitis tended to increase as litter moisture increased although the birds remained generally healthy and the mortality was low and similar for all groups.

The researchers did note that the protein levels in the experimental diets were raised by increasing the proportion of soybean meal, a feed ingredient that is associated with wet litter problems in broilers because its high potassium content causes the birds to drink more.

Dr Pirgozliev concluded: "The results suggest that a reduction in dietary crude protein levels can reduce the moisture in excreta and improve overall litter quality.

"This may also be achieved by an increase in the dietary amino acid digestibility coefficients," he added.

Further Reading

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You can view our previous article from the Turkey Science and Production Conference 2010 by clicking here.

August 2010