Atlanta Meeting Took a New Look at Litter

by 5m Editor
24 February 2010, at 12:00am

With conventional litter material getting ever more expensive and scarce, the search is on to look for alternatives. Several groups of researchers are looking into this area, and reported their findings at the International Poultry Scientific Forum (IPSF) in Atlanta last month, writes Jackie Linden, editor of ThePoultrySite.

Alternative Bedding Materials

The first of four papers on alternative bedding materials was presented by E.M. Shepherd from the University of Georgia. He and his colleagues investigated the suitability of gypsum as a bedding material for broiler chickens. He explained that the increasing price of bedding materials is putting a strain on broiler producers. As products such as pine shavings and rice hulls become more difficult to obtain, the law of supply and demand results in high prices of bedding materials.

Gypsum is a by-product of the housing industry and has shown some promise as a bedding material, he said, and so a trial was conducted to evaluate a 50:50 gypsum:pine shavings combination compared to pine shavings as a bedding material. These data suggest that gypsum could serve as a litter material for broiler production, as there were no differences between the groups housed on gypsum or shavings (control) in terms of performance, mortality or paw scores. There were some advantages in favour of the gypsum regarding ammonia concentration, litter moisture and pH, while percent caking was not different between the bedding materials.

Chopped switchgrass was evaluated as a sustainable litter material by J.D. Davis of Mississippi State University, who explained that switchgrass is a fast growing forage plant capable of producing eight to 12 tons per acre in Mississippi. He reported no differences in terms of live performance, mortality or carcass weights between groups of broilers kept on hammermilled switchgrass or pine shavings (control), and the researchers remarked that mean foot pad scores were better on chopped switchgrass.

A group from Pennsylvania State University also looked at biomass materials as bedding materials for broilers. R.M. Hulet reported on a comparison between conventional pine shavings and poplar shavings, chopped willow and chopped miscanthus grass. He and his co-workers concluded that these alternative bedding materials can be part of an overall sustainable system, grown by the producer (while providing benefits as vegetative buffers), harvested to use as a less expensive and readily available bedding and possible fuel source.

They found that body weight and feed intake were significantly lower at 14 days for the willow bedding but all were equal at 42 days. Feed conversion and mortality were not affected by bedding material at any age. At the end of the trial, the willow and poplar bedding resulted in significantly better litter scores than the pine shavings bedding. After 42 days of use, willow litter was found to be significantly higher in percent solids, and grass in total nitrogen. On an as-is basis, significant differences were found in stochiometric fuel analysis for percent carbon, hydrogen and oxygen, but not for overall gross energy value.

Another paper from Pennsylvania State University reported an investigation of turkey hen performance on river sand and pine shavings. R.M. Hulet concluded that while sand is not a satisfactory substitute for pine shavings during brooding, it did seem to perform equally well to pine shavings during the turkey finishing period. Hulet and Cravener had reared poults from day-old on sand or pine shavings. They found that body weight was significantly lower for birds brooded on the sand than the pine shavings at 12, 27, and 42 days of age although the difference was no longer significant by day 131. Mortality to 42 days was 11.5 per cent on sand and 1.9 per cent on shavings but bedding type did not affect mortality thereafter. No significant differences in litter scores or litter moisture were found between the two treatments.

Exploring the Link Between Litter Moisture and Broiler Welfare

Food pad dermatitis (FPD) incidence and severity in broiler chickens following exposure to wet litter were reported in a poster by O. Cengiz of Adnan Menderes University in Turkey and others at Auburn University. They found that FPD lesions as a result of exposure to litter moisture can be reversed if litter conditions subsequently improve, and that exposure to wet litter late in the growing period can increase both FPD incidence and severity.

In the first of their experiments, which used day-old chicks, wetting the litter increased the incidence of FPD on 14 day of the trial (53 versus eight per cent) but significantly reduced the FPD severity on day 46 (three versus 43 per cent) compared to un-wetted litter. Live body weight and feed conversion rate were similar for both treatments.

The second experiment involved 46-day-old broilers, with and without existing FPD. FPD incidence and severity were assessed on day 62. In birds without FPD at the start of the trial, FPD incidence was eight per cent on dry litter and 28 per cent on wetted litter on day 62. For those birds with FPD at the start of the trial, the severity of FPD increased to 63 per cent when kept on wetted litter but reduced to 11 per cent for the un-wetted litter. FPD incidence remained high (94 per cent) when birds were kept on wetted litter.

Litter as a Source of Chicken and Food-Borne Pathogens

Also from Auburn University, Z. Williams and colleagues presented a poster demonstrating the concentrations of different types of pathogenic bacteria at different depths in used broiler litter (pine shavings). They found fewer bacteria in the lower levels, which will help to develop litter management techniques in future that will reduce these disease threats.

The group measured total aerobes, anaerobes, Staphylococcus, E. coli, Clostridium perfringens concentrations, as well as testing for the presence of Salmonella and Campylobacter in litter samples were taken from the top two inches, the exact middle and the bottom two inches of the litter. Samples were taken every week from one week before bird placement until one week after bird removal.

Total numbers of all types of bacteria declined as the samples approach the bottom of the litter. No Campylobacter, E. coli, Salmonella or Cl. perfringens were recovered until the broilers were one week old. At certain sampling times, Salmonella, E. coli, Campylobacter and Cl. perfringens were not detected in the bottom layer of litter, while Staphylococcus was found at all depths.

The researchers stated that since litter management is crucial in maintaining good bird health, their results can be used to develop or refine litter management techniques to eliminate human pathogens from the litter, especially Staphylococcus.

Measuring and Reducing the Environmental Impact of Litter

Two oral papers presented at IPSF covered ammonia (NH3) emission from poultry litter.

In the introduction to his paper on NH3 concentrations downstream of broiler operations during the winter, Dr B.D. Fairchild from the University of Georgia explained that previous work indicated that NH3 emissions from broiler facilities dissipate rapidly during hot weather. The latest work, measuring NH3 emission during the winter, indicate that complaints from neighbours within around 100 metres of the experimental facility would be unlikely.

Repeating the previous experiment during the winter, open-path laser spectrometers were placed 300 and 500 feet from the houses, and data were collected during the last four weeks of a 56 day grow-out cycle.

The maximum NH3 concentrations measured was 1.3 ppm, which is considerably lower than the summer experiment, when the highest concentration was 2.9 ppm. These NH3 concentration were well below the reported EPA odour-detection threshold values of five to 50 ppm.

Also reporting work at the University of Georgia, C. Ritz discussed feeding char to broilers to reduce NH3 volatilisation from broiler litter. The NH3 concentration in the air was reduced significantly by the inclusion of char, without any negative effects on bird performance.

In the paper, it is explained that chars obtained by the pyrolysis of biomass can be transformed into activated carbons, which have been used to remove ammonia from air – mostly through its interaction with the carbons' oxygen functional groups via hydrogen bonding. The Georgia researchers used pine chips to produce the char.

In the study, broilers were fed standard diets containing 0, 1.6, 2.3 or 5.1 per cent char. The addition of char in broiler feed brought about a significant exponential decrease in NH3 concentration in the air that averaged 70 per cent at rates of char between two and five per cent, yet no adverse effects of char on broiler performance were detected.

A New Use for Turkey Litter

Heat Transfer International of Kentwood, Michigan has commercialised the world's first fixed-bed, starved air, low-temperature gasifier plant to convert turkey litter to green energy at Sietsema Feed Farms in Howard City, Michigan, according to that company's G.H. Shahani.

The technology simultaneously addresses three issues important to the turkey industry: environmental, energy and economics. The litter is converted to a dense ash that can be used for odourless fertiliser or cement additive, reducing concerns for nutrient run-off from over-application of animal manure. Furthermore, the process produces green energy in a cost-effective manner, it is reported, and the technology is ready for widespread commercial deployment in the poultry and meat industries.

Cengiz O., J.B. Hess and S.F. Bilgili. 2010. Effect of early and late exposure to litter moisture on foot pad dermatitis in broiler chickens. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. P149.

Davis J.D., J.L. Purswell and A.S. Kiess. 2010. Evaluation of chopped switchgrass as a sustainable litter material. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. T137

Fairchild B.D., M. Czarick, C.W. Ritz, J.W. Worley, L.A. Harper and N.P. Naeher. 2010. Ammonia concentrations downstream of broiler operations during winter. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. T139

Hulet R.M. and T.I. Cravener. 2010. Turkey hen performance on river sand and pine shavings bedding. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. T135.

Hulet R.M., P.H. Patterson, T.L. Cravener and T.A. Volk. 2010. Alternative bedding for broilers: from vegetative buffers to fuel. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. T138.

Shahani G.H., D. Prouty, H. Sietsema, and R. Sietsema. 2010. Green energy from turkey litter. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. T136.

Shepherd E.M., C.W. Ritz and B.D. Fairchild 2010. Evaluation of gypsum as a bedding material for broiler chickens. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. M42.

Tasistro, A., C. Ritz, D. Kissel and B. Fairchild. 2010 Feeding char to broilers to reduce ammonia volatilization from broiler litter. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. T133.

Williams Z., A. Segrest, M. Bailey, J. Krehling and K. Macklin. 2010. Concentrations of different types of pathogenic bacteria in varying levels of used broiler litter: top, middle and bottom. Proceedings of International Poultry Scientific Forum 2010, Atlanta, US. P153.

Further Reading

- You can view our previous report from IPSF 2010 by clicking here.

February 2010