Suitability of litter amendments for the Australian chicken meat industry

Abstract

The Australian chicken meat indutstry is rapidly expanding due to the increasing consumption of chicken meat. As a result, the industry has growing issues of sourcing new bedding materials and disposing of spent litter, which can be attributed, in part, to a lack of widespread litter re-use for rearing chickens. According to insights and perspectives recently gathered from industry stakeholders, it is believed that re-using litter will become more common in the future, so as to reduce production costs and ease pressures on both the supply of new bedding materials and disposal of spent litter. However, there are potential risks that need to be addressed if litter re-use increases, particularly with regard to the production and mitigation of ammonia, which can negatively affect chicken health if not managed correctly. The present review discusses the potential benefits reported for different types of litter amendments, which have the primary goal of reducing ammonia volatilisation, but may also contribute to improvements in bird performance, welfare, pathogen loads, fertiliser value of spent litter, and reduced costs associated with purchasing new bedding materials. Acidifiers have been shown to be the most effective of all amendment types, with sodium bisulfate or alum being among the most commonly tested products mentioned in research literature. Litter amendments are currently rarely used in Australia, but it is hoped that the information provided in the present review, based mostly on overseas usage and research, will help inform future decision-making on the use of these products in Australian poultry production systems.

Review of litter turning during a grow-out as a litter management practice to achieve dry and friable litter in poultry production

“…Once caked, chickens cannot naturally mix excreta into the litter resulting in the top layer of litter “slicking” over, causing cake to form on the litter surface ( Miles et al., 2008a , Miles et al., 2008b ). The properties of all bedding materials change during the grow-out as the ratio of manure to bedding increases, and litter used for multiple grow-outs can have superior water holding and water activity properties ( Dunlop et al., 2015 ; Dunlop, 2016a , Dunlop et al., 2016b , Dunlop et al., 2016c , Dunlop et al., 2016d ) and be more cost-effective than new bedding ( Roll et al., 2011 ), even if chemical litter amendments are added to manage ammonia production ( Worley et al., 2000 ; Cockerill et al., 2020 ).…”

“…Minimal published information was found that directly focused on the impacts of turning or breaking up litter on ammonia concentration. The concentration of ammonia in the house is affected by multiple factors ( Cockerill et al., 2020 ) including amount of ammonia produced in the litter (affected by diets, temperature, manure and moisture content ( Miles et al., 2006 ; van Emous et al., 2019 )), amount of ammonia exchanged between the litter and the air, amount of fresh air brought into the house (to dilute the ammonia), and amount of ammonia extracted from the house through the ventilation exhaust fans. Litter turning will not directly affect dilution or removal of ammonia by the ventilation system but will alter litter conditions affecting formation and emission of ammonia from the litter.…”

“…Accelerated moisture, gas, and particle emissions from the litter will occur at the time of litter turning due to increased surface area and potential exchange sites for molecules of water and other compounds ( Czarick et al., 2006 ; Estellés et al., 2011 ; Dunlop, 2016a , Dunlop et al., 2016b , Dunlop et al., 2016c , Dunlop et al., 2016d ; Malone and Marsh Johnson, 2017 ). Aerating the litter will also promote aerobic microbial activity and heat production that will further increase volatilization of water vapor and promote microbial decomposition of uric acid in the litter, which is one of the recognized sources for ammonia production ( Cockerill et al., 2020 ). Also, long-term aeration of litter has previously been shown to reduce ammonia production emissions ( Allen et al., 1998 ).…”

Effects of a Partially Perforated Flooring System on Ammonia Emissions in Broiler Housing—Conflict of Objectives between Animal Welfare and Environment?

“…In addition, the use of acids in pig and cattle slurry has proven to be effective in reducing the pH and thus the NH 3 release [ 65 , 66 ]. Similar approaches exist with pH-lowering litter additives in poultry production [ 67 , 68 ]. The partially perforated flooring system offers the possibility of testing a system to acidify the material below the elevated perforated area and thus reduce NH 3 volatilization.…”

Potential contaminants and hazards in alternative chicken bedding materials and proposed guidance levels: a review

“…Recent reviews of litter treatments showed that several litter amendments are suitable for use in poultry houses to reduce litter moisture and hence ammonia generation ( Cockerill et al., 2020 ; de Toledo et al., 2020 ).…”