- Email: [email protected]
Effects of frequency of multiple applications of litter amendment on litter ammonia and live performance in a shared airspace
©2013 Poultry Science Association, Inc.
Effects of frequency of multiple applications of litter amendment on litter ammonia and live performance in a shared airspace J. L. Purswell,*1 J. D. Davis,† A. S. Kiess,‡ and C. D. Coufal§ *Poultry Research Unit, USDA-Agricultural Research Service, Mississippi State, MS 39762; †Agricultural and Biological Engineering Department, and ‡Poultry Science Department, Mississippi State University, Mississippi State 39762; and §Poultry Science Department, Texas A&M University, College Station 77843 Primary Audience: Flock Supervisors, Researchers, Producers SUMMARY Mitigation of ammonia (NH3) volatilization from litter is of particular interest given its effects on broiler health and production efficiency, as well as air and water quality concerns. Typical management guidelines recommend aerial NH3 concentrations be limited to 25 ppm. However, concentrations in excess of this recommendation are common in winter months due to limited minimum ventilation to conserve heat. Litter amendments are an effective means to reduce ammonia volatilization and are applied to the litter before chick placement. In this study, we evaluated the effects of differing application frequencies of a sodium bisulfate-based litter amendment on bird performance and equilibrium litter NH3 concentrations. Treatments consisted of no amendment application (negative control), initial application before placement (positive control), and varied application schedules at 14, 28, and 43 d at 0.49 kg/m2 (100 lb/1,000 ft2). Repeated application of litter amendment did not affect live performance or foot pad quality. More frequent application of litter amendment significantly reduced equilibrium litter NH3 concentration when compared with the negative and positive controls. The most effective application program was biweekly, with significant reductions of 56.6 and 21.8% at d 42 and 57, respectively. Therefore, repeated application during growout can effectively mitigate ammonia volatilization from litter without incurring reductions in live performance or foot pad quality. Key words: litter management, ammonia, air quality 2013 J. Appl. Poult. Res. 22:469–473 http://dx.doi.org/10.3382/japr.2012-00669
DESCRIPTION OF PROBLEM Mitigation of aerial ammonia (NH3) remains an important topic of interest in commercial poultry production due to its effects on bird health, well-being, and production efficiency, as well as the potential for environmental effects. Ocular and respiratory health can be 1
Corresponding author: [email protected]
compromised from chronic exposure to aerial NH3 [1, 2]. Significant performance reductions occur as chronic exposure levels exceed 25 ppm, including reduced BW and poorer feed conversion [3]. Therefore, chronic exposure of poultry to aerial NH3 can also have significant detrimental economic effect to poultry producers.
JAPR: Research Report
470 Elevated NH3 concentrations typically occur in commercial broiler houses as a result of recycled litter usage coupled with reduced ventilation rates for fuel conservation. With properly designed and operated ventilation systems, ventilation rates sufficient for moisture removal should remove air contaminants [4]. In lieu of reducing NH3 production through reducing litter moisture via ventilation, the application of litter treatments, such as sodium bisulfate, aluminum sulfate, sulfuric acid, and ferric sulfate, to reduce NH3 production [5, 6] and volatilization [7] through litter acidification has become a widespread management practice throughout the commercial broiler industry. Application rates recommended by manufacturers range from 0.24 to 0.73 kg/m2 (50 to 150 lb/1,000 ft2) depending on the active ingredient (i.e., sodium bisulfate, alum, and so on) and previous litter management (e.g., in-house windrowing) [8]. Fairchild et al. [9] evaluated increased application rates for sodium bisulfate litter amendment (poultry litter treatment; PLT) to determine the lifespan of NH3 mitigation ability. Overall aerial NH3 concentrations were reduced as application rates increased from 0.24 to 0.73 kg/m2 and extended NH3 suppression for an additional week. In addition, more nitrogen was retained in the litter in the form of ammonium. Given the limited extensions of the duration of mitigation potential from increased initial application, another strategy to consider would be multiple applications over the life of the flock. Li et al. [10] evaluated weekly application of PLT in environmental chambers at application rates of 0.18 and 0.37 kg/m2 (37.5 and 75 lb/1,000 ft2). No significant differences in live performance were observed; however, NH3 emission rates were significantly reduced. The objective of this research was to evaluate the effects of application frequency of a sodium bisulfate litter amendment at the manufacturer’s recommended rate on performance of broiler chickens and litter ammonia volatilization.
MATERIALS AND METHODS A total of 920 straight-run broiler chickens [11] were obtained from a commercial hatchery for each trial and randomly allocated to 20 pens in a tunnel-ventilated research facility, result-
ing in 4 replicate pens per treatment. A total of 2,760 broilers were used over the 3 trials in the study. The first trial began in September 2011, and the time between each flock was kept at 14 d to mimic industry practice. Birds were housed in pens measuring 1.5 × 2.7 m (5 × 9 ft) to 56 d of age and stocked at 42 birds/pen. Each pen was equipped with tube feeders and nipple drinkers, and feed and water were available ad libitum. Ventilation was managed according to typical poultry housing guidelines [12, 13], with ventilation rates of 0.17 m3/h per bird (0.10 ft3/min per bird) and 0.42 m3/h per bird (0.25 ft3/min per bird) during wk 1 and 2, respectively, and to maintain temperature setpoints from wk 3 to 8. The pens contained pine shavings litter that had been used with 1 previous flock. Treatments were held constant in each pen for all 3 trials to assess the effects of repeated amendment application over multiple flock cycles. A sodium bisulfate-based litter amendment [14] was used for each application in each trial. The litter amendment was applied to the surface of the litter according to the schedule in Table 1 at the manufacturer’s recommended rate (0.48 kg/m2; 100 lb/1,000 ft2). Ammonia volatilization from the litter was assessed by measuring equilibrium NH3 concentrations [15, 16] with a photoacoustic infrared gas analyzer [17] and a dynamic flux chamber [18] placed on the litter on d −1, 13, 27, and 42, and on d 57 after birds were removed from the pens. The dynamic flux chamber method was used to measure equilibrium NH3 concentrations, as all pens shared a common airspace and emissions could not be measured directly. All equilibrium concentrations measurements were taken before the litter amendment application in 1 location near the center of each pen to avoid areas near the drinker line and feeder that typically have increased litter moisture and may increase the variability of equilibrium NH3 concentrations. Chick placement was considered d 0 for each trial. The following 4-phase feeding schedule was used: starter (placement to d 14), grower (d 15–29), finisher (d 30–43), and withdrawal (d 44–56). Diet compositions have previously been reported by Dozier et al. [19]. The weight of all birds in each pen and feed consumption were obtained on d 14, 29, 43, and 56. Foot pad quality was assessed on flocks 1 and 3; foot pad
Purswell et al.: LITTER AMENDMENT APPLICATION Table 1. Litter amendment application frequency treatment schedule1 Treatment
Application schedule (d)
A B C D E
Negative control −1 (positive control) −1 and 28 −1, 14, 28, and 43 −1, 28, and 43
1
Day −1 = the day before chick placement.
scores (FPS) were obtained for 6 birds per pen (3 male and 3 female) [20] per Nagaraj et al. [21] on d 56. All procedures were approved by the USDA-Agricultural Research Service Animal Care and Use Committee at the Mississippi State location. For statistical analysis, a randomized complete block design was used, with trial serving as the blocking factor. All analyses were performed using PROC MIXED in SAS [22]. No treatment × trial interactions were observed, and data from all 3 trials were pooled for analysis. Means were separated using Fisher’s LSD, with significance considered at P ≤ 0.05.
RESULTS AND DISCUSSION Live performance results are shown in Table 2. No significant differences in live performance were observed among treatment groups, indicating multiple applications of the litter amendment did not affect live performance or mortality. These findings agree with those of Li et al. [10]. The shared airspace in the current study precluded determinations of potential effects on performance due to changes in aerial NH3 concentration resulting from repeated amendment application. Additionally, Li et al. [10] reported similar results from a larger scale study with a limited aerial NH3 concentration at a maximum of 25 ppm, which may not realistically simulate typical commercial conditions. Foot pad quality was generally improved through addition of litter amendment (Table 3), with treatment B having the best footpad quality. The negative control (treatment A) and application at d −1, 28, and 42 (treatment C) had fewer birds with no foot pad lesions (FPS = 0). The negative control also had a significantly higher incidence of lesions <1.5 cm (FPS = 1) when
471
Table 2. Live performance responses for straight-run broilers under different litter amendment application frequencies during growout to 56 d of age1 Treatment2
BW gain (g/bird)
FI3 (g/bird)
FCR (g:g)
Mortality (%)
A B C D E SEM P-value
3,883 3,915 3,851 3,869 3,919 32 0.483
7,362 7,285 7,271 7,285 7,357 41 0.377
1.88 1.86 1.87 1.87 1.86 0.01 0.554
1.5 0.4 1.1 1.0 0.9 0.1 0.646
1
Table values represent LSM for 12 pens (4 replicate pens × 3 trials) having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 3 FI = feed intake.
compared with the remaining treatments. Cumulative FPS for trials 1 and 3 are presented in Table 4; foot pad quality decreased significantly in trial 3 (P ≤ 0.0001). Biweekly application (treatment E) and single application (treatment B) had the lowest cumulative FPS in trial 3; thus, reduced FPS does not appear to be correlated to frequency of application in this study. Nagaraj et al. [21] evaluated the effects of application rate of PLT on pododermititis and found no differences in FPS attributable to the addition of PLT. However, Li et al. [10] found significant improvements in FPS with weekly applications at
Table 3. Mean incidence (%) of broiler foot pad scores (FPS) for different litter amendment application frequencies during growout assessed at 56 d of age1 Treatment2
FPS3 = 0 (%)
FPS = 1 (%)
FPS = 2 (%)
A B C D E SEM P-value
78.1c 98.9a 87.5bc 92.7ab 94.8ab 3.6 0.0011
20.8a 1.0b 8.3b 2.1b 5.2b 3.1 <0.0001
1.0 0.0 4.2 5.2 0.0 1.8 0.14
a–c Means within a column having different superscripts are significantly different at P ≤ 0.05. 1 Table values represent LSM for 8 pens (4 replicate pens × 2 trials) having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 3 Foot pad quality was assessed using a 3-point system where lesions were assigned the following scores according to severity: 0 = no lesions, 1 = lesions <1.5 cm, and 2 = lesions >1.5 cm.
JAPR: Research Report
472 Table 4. Mean cumulative foot pad scores for different litter amendment application frequencies during growout assessed at 56 d of age1 Treatment2 A B C D E SEM P-value
Trial 13 a
0.15 0.00b 0.00b 0.00b 0.00b 0.02 <0.0001
Trial 3 0.31a 0.02c 0.33a 0.25ab 0.10bc 0.07 0.0054
a–c
Means within a column having different superscripts are significantly different at P ≤ 0.05. 1 Table values represent least squares means for 4 pens/trial having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 3 Foot pad quality was assessed using a 3-point system where lesions were assigned the following scores according to severity: 0 = no lesions, 1 = lesions <1.5 cm, and 2 = lesions >1.5 cm.
both 0.18 and 0.37 kg/m2 (37.5 and 75 lb/1,000 ft2) when compared with no application. Mean dynamic flux chamber equilibrium NH3 concentrations are shown in Table 5. No significant differences in chamber equilibrium NH3 concentrations were observed through d 27 for any treatment. All treatments resulted in reduced NH3 concentration from d −1 to 14; this reduction is likely a product of increased NH3 volatilization from heating and bird activity and low rates of feces deposition on the litter with young birds. Significant reductions were observed at d 42 (56.6% reduction) and 57 (21.8% reduction) for a 2-wk application frequency (treatment D) when compared with the negative control (treatment A). Significant reductions were also observed at d 42 (60.4% reduction)
and 57 (31.1% reduction) for treatment D when compared with the positive control (treatment B). Reductions in equilibrium NH3 concentration over time are likely higher than those reported here, as measurements were taken at the end of each 2-wk period; Li et al. [10] noted increased reductions in emissions immediately after repeated applications of PLT. Whereas treatment E showed significant reductions at d 42 and 57 when compared with the positive control (39.6 and 9.0%, respectively), it was not different from the negative control. Treatments D and E were not significantly different, suggesting that application after the brooding period (i.e., d 14) is less critical than achieving a threshold amount of litter amendment applied for reduction of litter NH3. Significant reductions in performance have been observed when broilers were subjected to aerial NH3 concentrations in excess of 25 ppm [3]; hence reductions in aerial NH3 will likely translate into improved performance under commercial conditions [23]. As ventilation rates increase with bird age to control temperature during moderate and warm weather, aerial NH3 concentrations are normally kept below 25 ppm, thus repeated application may not improve performance under these conditions, but will likely provide reductions in NH3 emissions. However, this may not always be the case in periods of extremely cold weather, and mitigation of ammonia volatilization in the later stages of growout may result in improved broiler performance. Repeated application of the litter amendment in commercial-scale poultry production facilities will require development of distribu-
Table 5. Mean dynamic flux chamber equilibrium ammonia concentrations for different litter amendment application frequencies during broiler growout to d 561 Treatment2 A B C D E SEM P-value a–c
d −1 (ppm) 64.0 70.3 82.4 64.0 80.1 18.2 0.920
d 13 (ppm) 15.6 10.5 10.3 12.7 13.8 2.2 0.396
d 27 (ppm) 24.8 15.8 15.1 11.8 11.9 3.5 0.074
d 42 (ppm) ab
219.9 241.0a 148.1abc 95.4c 132.8bc 36.5 0.038
d 57 (ppm) 255.8ab 290.1a 243.3b 199.9c 232.7bc 14.8 0.003
Means within a column having different superscripts are significantly different at P ≤ 0.05. Table values represent least squares means for 12 pens (4 replicate pens × 3 trials) having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 1
Purswell et al.: LITTER AMENDMENT APPLICATION tion systems; distribution system development should be focused on accurate placement of litter amendment to minimize equipment maintenance issues. Further studies under commercialtype ventilation and environment are warranted to determine how live performance may be affected, and the economic effect of repeated application.
CONCLUSIONS AND APPLICATIONS
1. Multiple applications of the sodium bisulfate litter amendment at the manufacturer’s recommended rate (0.48 kg/m2; 100 lb/1,000 ft2) on a biweekly basis reduced litter ammonia concentrations by 56.6 and 21.8% at d 42 and 57, respectively. 2. Live performance was not affected by repeated additions of the sodium bisulfate litter amendment. 3. Further studies under commercial-type ventilation and environment are warranted to determine the effects of repeated litter amendment applications on live performance, equipment maintenance issues, and economic effect.
REFERENCES AND NOTES 1. Miles, D. M., W. W. Miller, S. L. Branton, W. R. Maslin, and B. D. Lott. 2006. Ocular responses to ammonia in broiler chickens. Avian Dis. 50:45–49. 2. Kristensen, H. H., and C. M. Wathes. 2000. Ammonia and poultry welfare: A review. World’s Poult. Sci. J. 56:235–245. 3. Miles, D. M., S. L. Branton, and B. D. Lott. 2004. Atmospheric ammonia is detrimental to the performance of modern commercial broilers. Poult. Sci. 83:1650–1654. 4. Albright, L. D. 1990. Environment Control for Animals and Plants. ASAE, St. Joseph, MI. 5. Pope, M. J., and T. E. Cherry. 2000. An evaluation of the presence of pathogens on broilers raised on poultry litter treatment-treated litter. Poult. Sci. 79:1351–1355. 6. Blake, J. P., and J. B. Hess. 2001. Sodium bisulfate (PLT) as a litter amendment. ANR-1208. Alabama Cooperative Extension Service, Auburn University, Auburn, AL. 7. Choi, I. H., and P. A. Moore Jr. 2008. Effect of various litter amendments on ammonia volatilization and nitrogen content of poultry litter. J. Appl. Poult. Res. 17:454–462. 8. Shah, S., P. Westerman, and J. Parsons. 2006. Poultry litter amendments. AG-657. North Carolina Cooperative Extension Service, Raleigh.
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9. Fairchild, B. D., J. W. Worley, M. Czarick, and C. W. Ritz. 2006. Effects of heavy application of litter amendment on broiler house ammonia concentration. ASABE Meeting Paper No. 064187, ASABE, St. Joseph, MI. 10. Li, H., C. Lin, S. Collier, S. White-Hansen, and W. Brown. 2012. Assessment of repeated litter amendment application on ammonia reduction. ASABE Meeting Paper No. 12–1337336, ASABE, St. Joseph, MI. 11. Ross × Ross 708. Aviagen Inc., Huntsville, AL. 12. Donald, J. O., M. Eckman, and G. Simpson. 2002. Cardinal rules for wintertime broiler house ventilation. Alabama Poult. Eng. Econ. Newsletter, Vol. 15. Alabama Cooperative Extension Service, Auburn. 13. Aviagen Inc. 2009. Broiler management manual. Aviagen Inc., Huntsville, AL. 14. Poultry Litter Treatment (PLT). Jones-Hamilton, Walbridge, OH. 15. Gates, R. S., J. L. Taraba, N. S. Ferguson, and L. W. Turner. 1997. A technique for determining ammonia equilibrium and volatilization from broiler litter. ASAE Paper No. 97–4074, ASAE, St. Joseph, MI. 16. Bilgili, S. F., J. B. Hess, K. S. Macklin, B. Saenmahayak, and J. L. Sibley. 2009. Influence of bedding material on footpad dermatitis in broiler chickens. J. Appl. Poult. Res. 18:583–589. 17. Chillgard RT. MSA Safety, Murrysville, PA. 18. Woodbury, B. L., D. N. Miller, R. A. Eigenberg, and J. A. Nienaber. 2006. An inexpensive laboratory and field chamber for manure volatile gas analysis. Trans. ASABE 49:767–772. 19. Dozier, W. A., III, A. Corzo, M. T. Kidd, and M. W. Schilling. 2008. Dietary digestible lysine requirements of male and female broilers from forty-nine to sixty-three days of age. Poult. Sci. 87:1385–1391. 20. Foot pad quality was assessed using a three-point system, where lesions were assigned the following scores according to severity: 0 = no lesions, 1 = lesions < 1.5 cm, and 2 = lesions > 1.5 cm. 21. Nagaraj, M., C. A. P. Wilson, B. Saenmahayak, J. B. Hess, and S. F. Bilgili. 2007. Efficacy of a litter amendment to reduce pododermatitis in broiler chickens. J. Appl. Poult. Res. 16:255–261. 22. SAS/STAT User’s Guide. 2008. Version 9.2 ed. SAS Inst. Inc., Cary, NC. 23. Terzich, M., C. Quarles, M. A. Goodwin, and J. Brown. 1998. Effect of Poultry Litter Treatment® (PLT®) on the development of respiratory tract lesions in broilers. Avian Pathol. 27:566–569.
Acknowledgments
The authors gratefully acknowledge the efforts of USDA-Agricultural Research Service, Poultry Research Unit engineering technicians Jason Johnson and William Elliott in data collection during this study and Brian Fairchild (University of Georgia, Athens) and Yi Liang (University of Arkansas, Fayetteville) for critical review of the manuscript.
Effects of frequency of multiple applications of litter amendment on litter ammonia and live performance in a shared airspace J. L. Purswell,*1 J. D. Davis,† A. S. Kiess,‡ and C. D. Coufal§ *Poultry Research Unit, USDA-Agricultural Research Service, Mississippi State, MS 39762; †Agricultural and Biological Engineering Department, and ‡Poultry Science Department, Mississippi State University, Mississippi State 39762; and §Poultry Science Department, Texas A&M University, College Station 77843 Primary Audience: Flock Supervisors, Researchers, Producers SUMMARY Mitigation of ammonia (NH3) volatilization from litter is of particular interest given its effects on broiler health and production efficiency, as well as air and water quality concerns. Typical management guidelines recommend aerial NH3 concentrations be limited to 25 ppm. However, concentrations in excess of this recommendation are common in winter months due to limited minimum ventilation to conserve heat. Litter amendments are an effective means to reduce ammonia volatilization and are applied to the litter before chick placement. In this study, we evaluated the effects of differing application frequencies of a sodium bisulfate-based litter amendment on bird performance and equilibrium litter NH3 concentrations. Treatments consisted of no amendment application (negative control), initial application before placement (positive control), and varied application schedules at 14, 28, and 43 d at 0.49 kg/m2 (100 lb/1,000 ft2). Repeated application of litter amendment did not affect live performance or foot pad quality. More frequent application of litter amendment significantly reduced equilibrium litter NH3 concentration when compared with the negative and positive controls. The most effective application program was biweekly, with significant reductions of 56.6 and 21.8% at d 42 and 57, respectively. Therefore, repeated application during growout can effectively mitigate ammonia volatilization from litter without incurring reductions in live performance or foot pad quality. Key words: litter management, ammonia, air quality 2013 J. Appl. Poult. Res. 22:469–473 http://dx.doi.org/10.3382/japr.2012-00669
DESCRIPTION OF PROBLEM Mitigation of aerial ammonia (NH3) remains an important topic of interest in commercial poultry production due to its effects on bird health, well-being, and production efficiency, as well as the potential for environmental effects. Ocular and respiratory health can be 1
Corresponding author: [email protected]
compromised from chronic exposure to aerial NH3 [1, 2]. Significant performance reductions occur as chronic exposure levels exceed 25 ppm, including reduced BW and poorer feed conversion [3]. Therefore, chronic exposure of poultry to aerial NH3 can also have significant detrimental economic effect to poultry producers.
JAPR: Research Report
470 Elevated NH3 concentrations typically occur in commercial broiler houses as a result of recycled litter usage coupled with reduced ventilation rates for fuel conservation. With properly designed and operated ventilation systems, ventilation rates sufficient for moisture removal should remove air contaminants [4]. In lieu of reducing NH3 production through reducing litter moisture via ventilation, the application of litter treatments, such as sodium bisulfate, aluminum sulfate, sulfuric acid, and ferric sulfate, to reduce NH3 production [5, 6] and volatilization [7] through litter acidification has become a widespread management practice throughout the commercial broiler industry. Application rates recommended by manufacturers range from 0.24 to 0.73 kg/m2 (50 to 150 lb/1,000 ft2) depending on the active ingredient (i.e., sodium bisulfate, alum, and so on) and previous litter management (e.g., in-house windrowing) [8]. Fairchild et al. [9] evaluated increased application rates for sodium bisulfate litter amendment (poultry litter treatment; PLT) to determine the lifespan of NH3 mitigation ability. Overall aerial NH3 concentrations were reduced as application rates increased from 0.24 to 0.73 kg/m2 and extended NH3 suppression for an additional week. In addition, more nitrogen was retained in the litter in the form of ammonium. Given the limited extensions of the duration of mitigation potential from increased initial application, another strategy to consider would be multiple applications over the life of the flock. Li et al. [10] evaluated weekly application of PLT in environmental chambers at application rates of 0.18 and 0.37 kg/m2 (37.5 and 75 lb/1,000 ft2). No significant differences in live performance were observed; however, NH3 emission rates were significantly reduced. The objective of this research was to evaluate the effects of application frequency of a sodium bisulfate litter amendment at the manufacturer’s recommended rate on performance of broiler chickens and litter ammonia volatilization.
MATERIALS AND METHODS A total of 920 straight-run broiler chickens [11] were obtained from a commercial hatchery for each trial and randomly allocated to 20 pens in a tunnel-ventilated research facility, result-
ing in 4 replicate pens per treatment. A total of 2,760 broilers were used over the 3 trials in the study. The first trial began in September 2011, and the time between each flock was kept at 14 d to mimic industry practice. Birds were housed in pens measuring 1.5 × 2.7 m (5 × 9 ft) to 56 d of age and stocked at 42 birds/pen. Each pen was equipped with tube feeders and nipple drinkers, and feed and water were available ad libitum. Ventilation was managed according to typical poultry housing guidelines [12, 13], with ventilation rates of 0.17 m3/h per bird (0.10 ft3/min per bird) and 0.42 m3/h per bird (0.25 ft3/min per bird) during wk 1 and 2, respectively, and to maintain temperature setpoints from wk 3 to 8. The pens contained pine shavings litter that had been used with 1 previous flock. Treatments were held constant in each pen for all 3 trials to assess the effects of repeated amendment application over multiple flock cycles. A sodium bisulfate-based litter amendment [14] was used for each application in each trial. The litter amendment was applied to the surface of the litter according to the schedule in Table 1 at the manufacturer’s recommended rate (0.48 kg/m2; 100 lb/1,000 ft2). Ammonia volatilization from the litter was assessed by measuring equilibrium NH3 concentrations [15, 16] with a photoacoustic infrared gas analyzer [17] and a dynamic flux chamber [18] placed on the litter on d −1, 13, 27, and 42, and on d 57 after birds were removed from the pens. The dynamic flux chamber method was used to measure equilibrium NH3 concentrations, as all pens shared a common airspace and emissions could not be measured directly. All equilibrium concentrations measurements were taken before the litter amendment application in 1 location near the center of each pen to avoid areas near the drinker line and feeder that typically have increased litter moisture and may increase the variability of equilibrium NH3 concentrations. Chick placement was considered d 0 for each trial. The following 4-phase feeding schedule was used: starter (placement to d 14), grower (d 15–29), finisher (d 30–43), and withdrawal (d 44–56). Diet compositions have previously been reported by Dozier et al. [19]. The weight of all birds in each pen and feed consumption were obtained on d 14, 29, 43, and 56. Foot pad quality was assessed on flocks 1 and 3; foot pad
Purswell et al.: LITTER AMENDMENT APPLICATION Table 1. Litter amendment application frequency treatment schedule1 Treatment
Application schedule (d)
A B C D E
Negative control −1 (positive control) −1 and 28 −1, 14, 28, and 43 −1, 28, and 43
1
Day −1 = the day before chick placement.
scores (FPS) were obtained for 6 birds per pen (3 male and 3 female) [20] per Nagaraj et al. [21] on d 56. All procedures were approved by the USDA-Agricultural Research Service Animal Care and Use Committee at the Mississippi State location. For statistical analysis, a randomized complete block design was used, with trial serving as the blocking factor. All analyses were performed using PROC MIXED in SAS [22]. No treatment × trial interactions were observed, and data from all 3 trials were pooled for analysis. Means were separated using Fisher’s LSD, with significance considered at P ≤ 0.05.
RESULTS AND DISCUSSION Live performance results are shown in Table 2. No significant differences in live performance were observed among treatment groups, indicating multiple applications of the litter amendment did not affect live performance or mortality. These findings agree with those of Li et al. [10]. The shared airspace in the current study precluded determinations of potential effects on performance due to changes in aerial NH3 concentration resulting from repeated amendment application. Additionally, Li et al. [10] reported similar results from a larger scale study with a limited aerial NH3 concentration at a maximum of 25 ppm, which may not realistically simulate typical commercial conditions. Foot pad quality was generally improved through addition of litter amendment (Table 3), with treatment B having the best footpad quality. The negative control (treatment A) and application at d −1, 28, and 42 (treatment C) had fewer birds with no foot pad lesions (FPS = 0). The negative control also had a significantly higher incidence of lesions <1.5 cm (FPS = 1) when
471
Table 2. Live performance responses for straight-run broilers under different litter amendment application frequencies during growout to 56 d of age1 Treatment2
BW gain (g/bird)
FI3 (g/bird)
FCR (g:g)
Mortality (%)
A B C D E SEM P-value
3,883 3,915 3,851 3,869 3,919 32 0.483
7,362 7,285 7,271 7,285 7,357 41 0.377
1.88 1.86 1.87 1.87 1.86 0.01 0.554
1.5 0.4 1.1 1.0 0.9 0.1 0.646
1
Table values represent LSM for 12 pens (4 replicate pens × 3 trials) having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 3 FI = feed intake.
compared with the remaining treatments. Cumulative FPS for trials 1 and 3 are presented in Table 4; foot pad quality decreased significantly in trial 3 (P ≤ 0.0001). Biweekly application (treatment E) and single application (treatment B) had the lowest cumulative FPS in trial 3; thus, reduced FPS does not appear to be correlated to frequency of application in this study. Nagaraj et al. [21] evaluated the effects of application rate of PLT on pododermititis and found no differences in FPS attributable to the addition of PLT. However, Li et al. [10] found significant improvements in FPS with weekly applications at
Table 3. Mean incidence (%) of broiler foot pad scores (FPS) for different litter amendment application frequencies during growout assessed at 56 d of age1 Treatment2
FPS3 = 0 (%)
FPS = 1 (%)
FPS = 2 (%)
A B C D E SEM P-value
78.1c 98.9a 87.5bc 92.7ab 94.8ab 3.6 0.0011
20.8a 1.0b 8.3b 2.1b 5.2b 3.1 <0.0001
1.0 0.0 4.2 5.2 0.0 1.8 0.14
a–c Means within a column having different superscripts are significantly different at P ≤ 0.05. 1 Table values represent LSM for 8 pens (4 replicate pens × 2 trials) having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 3 Foot pad quality was assessed using a 3-point system where lesions were assigned the following scores according to severity: 0 = no lesions, 1 = lesions <1.5 cm, and 2 = lesions >1.5 cm.
JAPR: Research Report
472 Table 4. Mean cumulative foot pad scores for different litter amendment application frequencies during growout assessed at 56 d of age1 Treatment2 A B C D E SEM P-value
Trial 13 a
0.15 0.00b 0.00b 0.00b 0.00b 0.02 <0.0001
Trial 3 0.31a 0.02c 0.33a 0.25ab 0.10bc 0.07 0.0054
a–c
Means within a column having different superscripts are significantly different at P ≤ 0.05. 1 Table values represent least squares means for 4 pens/trial having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 3 Foot pad quality was assessed using a 3-point system where lesions were assigned the following scores according to severity: 0 = no lesions, 1 = lesions <1.5 cm, and 2 = lesions >1.5 cm.
both 0.18 and 0.37 kg/m2 (37.5 and 75 lb/1,000 ft2) when compared with no application. Mean dynamic flux chamber equilibrium NH3 concentrations are shown in Table 5. No significant differences in chamber equilibrium NH3 concentrations were observed through d 27 for any treatment. All treatments resulted in reduced NH3 concentration from d −1 to 14; this reduction is likely a product of increased NH3 volatilization from heating and bird activity and low rates of feces deposition on the litter with young birds. Significant reductions were observed at d 42 (56.6% reduction) and 57 (21.8% reduction) for a 2-wk application frequency (treatment D) when compared with the negative control (treatment A). Significant reductions were also observed at d 42 (60.4% reduction)
and 57 (31.1% reduction) for treatment D when compared with the positive control (treatment B). Reductions in equilibrium NH3 concentration over time are likely higher than those reported here, as measurements were taken at the end of each 2-wk period; Li et al. [10] noted increased reductions in emissions immediately after repeated applications of PLT. Whereas treatment E showed significant reductions at d 42 and 57 when compared with the positive control (39.6 and 9.0%, respectively), it was not different from the negative control. Treatments D and E were not significantly different, suggesting that application after the brooding period (i.e., d 14) is less critical than achieving a threshold amount of litter amendment applied for reduction of litter NH3. Significant reductions in performance have been observed when broilers were subjected to aerial NH3 concentrations in excess of 25 ppm [3]; hence reductions in aerial NH3 will likely translate into improved performance under commercial conditions [23]. As ventilation rates increase with bird age to control temperature during moderate and warm weather, aerial NH3 concentrations are normally kept below 25 ppm, thus repeated application may not improve performance under these conditions, but will likely provide reductions in NH3 emissions. However, this may not always be the case in periods of extremely cold weather, and mitigation of ammonia volatilization in the later stages of growout may result in improved broiler performance. Repeated application of the litter amendment in commercial-scale poultry production facilities will require development of distribu-
Table 5. Mean dynamic flux chamber equilibrium ammonia concentrations for different litter amendment application frequencies during broiler growout to d 561 Treatment2 A B C D E SEM P-value a–c
d −1 (ppm) 64.0 70.3 82.4 64.0 80.1 18.2 0.920
d 13 (ppm) 15.6 10.5 10.3 12.7 13.8 2.2 0.396
d 27 (ppm) 24.8 15.8 15.1 11.8 11.9 3.5 0.074
d 42 (ppm) ab
219.9 241.0a 148.1abc 95.4c 132.8bc 36.5 0.038
d 57 (ppm) 255.8ab 290.1a 243.3b 199.9c 232.7bc 14.8 0.003
Means within a column having different superscripts are significantly different at P ≤ 0.05. Table values represent least squares means for 12 pens (4 replicate pens × 3 trials) having 42 birds/pen at placement. 2 Refer to Table 1 for treatment descriptions. 1
Purswell et al.: LITTER AMENDMENT APPLICATION tion systems; distribution system development should be focused on accurate placement of litter amendment to minimize equipment maintenance issues. Further studies under commercialtype ventilation and environment are warranted to determine how live performance may be affected, and the economic effect of repeated application.
CONCLUSIONS AND APPLICATIONS
1. Multiple applications of the sodium bisulfate litter amendment at the manufacturer’s recommended rate (0.48 kg/m2; 100 lb/1,000 ft2) on a biweekly basis reduced litter ammonia concentrations by 56.6 and 21.8% at d 42 and 57, respectively. 2. Live performance was not affected by repeated additions of the sodium bisulfate litter amendment. 3. Further studies under commercial-type ventilation and environment are warranted to determine the effects of repeated litter amendment applications on live performance, equipment maintenance issues, and economic effect.
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Acknowledgments
The authors gratefully acknowledge the efforts of USDA-Agricultural Research Service, Poultry Research Unit engineering technicians Jason Johnson and William Elliott in data collection during this study and Brian Fairchild (University of Georgia, Athens) and Yi Liang (University of Arkansas, Fayetteville) for critical review of the manuscript.