Effect of commercial broiler house retrofit: A 4-year study of live performance

Transcription

1 2013 Poultry Science Association, Inc. Effect of commercial broiler house retrofit: A 4-year study of live performance Y. Liang,* 1 M. T. Kidd, S. E. Watkins, and G. T. Tabler * Department of Biological and Agricultural Engineering, and Department of Poultry Science, University of Arkansas, Fayetteville 72701; and Department of Poultry Science, Mississippi State University, Mississippi State Primary Audience: Flock Supervisors, Researchers, Poultry Producers SUMMARY Poultry producers have experienced increased production efficiency that is partially attributable to advances in housing technology and instrumentation. This advancement, coupled with continual strain improvements in commercial broilers for growth rate, FE, and livability, results in realized annual improvements in productivity. In this study, we present data on performance collected between 2004 and 2008 from a commercial 4-house farm at the University of Arkansas Applied Broiler Research Farm. Preretrofit years were 2004 to 2005 and postretrofit years were 2006 to Performance improvements due to housing and equipment changes, including replacing curtain-sided with totally enclosed housing systems, were quantified by measuring the difference between this farm and the industry live performance for corresponding years. In our comparison, we demonstrated that after the contribution of yearly strain improvements and associated nutritional and health programs are taken into account, modern broiler housing with better environmental-control capability is important for optimizing weight gain, feed conversion, and livability. Key words: broiler, feed conversion, mortality, performance, average daily weight gain 2013 J. Appl. Poult. Res. 22 : DESCRIPTION OF PROBLEM The low FCR achieved in the broiler sector make poultry production among the most efficient means of producing animal protein [1]. The domestic consumption of chicken meat per capita has grown 205% from 1960 to 2011 (from 19.2 pounds in 1960 to 58.5 pounds in 2011), accounting for 35% of US meat consumption [2]. In 2011, 8.6 billion broilers were raised in the United States, yielding a farm-gate value of $23 billion [3]. The gain in production efficiency, such as growth rate and calorie conversion, primarily comes from a combination of primary breeder genetic selection, nutrition, animal husbandry (including environmental control), and poultry health. During a period of 15 yr ( ), the time required to grow a broiler to 5 pounds live weight has decreased by more than a week [4]. Annual live production on a Georgia broiler farm, after ventilation and watering system upgrades, increased from 124 kg/m 2 (25.3 lb/ft 2 ) in 1986 to 171 kg/m 2 (34.9 lb/ft 2 ) in 1996 because of overall improved flock performance [5]. Proper management of the housing environment during cleanout and grow-out is critical to realize the genetic potential in broilers. 1 Corresponding author: yliang@uark.edu

2 212 JAPR: Research Report Broiler houses have gone through different configurations in terms of housing characteristics and equipment, with varying heating, ventilation, and cooling systems. Modern broiler houses have better environmental control due to the elimination of sidewall curtains and addition of central computer-controlled heating, ventilation, and cooling systems, including static pressure-controlled sidewall inlets and the capability for tunnel ventilation. As poultry producers face rapidly rising costs of energy, a trend was observed in recent years for producers to increase farm energy efficiency by converting conventional houses to solid-wall houses, improved insulation values in walls and ceilings, improved house tightness, improved energy-efficient lighting, and improved energy-efficient heating equipment [6]. Besides the potential energy savings as a result of the house retrofit, some technologies employed by the producers also help to improve flock performance. Traditionally, fabric-based curtains provide closure control for a large surface area of sidewalls, but allow infiltration above the top seam of the curtain or through the bottom or end-pocket [7]. By replacing sidewall curtains with solid walls, house tightness is greatly improved. It allows for better ventilation management, uniform temperature distribution inside the house, and less condensation on interior surfaces that could cause wet litter. To date, the synergistic effect of genetic strain, nutrition, and husbandry improvement of the broilers makes it hard to compare the production responses from different time spans. However, this information is needed for those who consider starting a poultry operation business or those who face a renovation decision. In this study, we evaluated a 4-house contract commercial broiler farm owned by the University of Arkansas. The broiler houses were constructed as curtain-sided conventional houses in 1990 and completely renovated as solid-wall enclosed houses in early Energy consumption before and after farm renovation was previously compared [8]. The objectives of this study were (1) to compare and elucidate production responses before and after farm renovation using data collected on 12 flocks before ( ) and 12 flocks after ( ) renovation (24 total flocks) and (2) compare the production responses from the test farm and the overall industry live performance over the same time period. MATERIALS AND METHODS Broiler Houses General description of the 4 broiler houses before and after the renovation was previously reported [8, 9], and is given here for clarification purpose (Table 1). Each house measured m ( ft). Due to the consideration of energy research when the farm was initially built, the 4 houses had a different configuration before renovation. Two of the 4 houses had drop ceiling, whereas the other 2 houses had rigidfoam roof insulation. Two of the houses had side curtains (height of 75 cm) along the full length of both south and north sides (i.e., naturally ventilated houses). The south side of the other 2 houses (i.e., tunnel houses) had 2 sections of 100-ft experimental cooling pads on the wall with the remainder as curtain. The cooling pad openings were covered by 2 rows of static pressure-controlled sliding doors on the inside when not in use. The tunnel inlet configuration of these 2 houses was different from the typical design of tunnel ventilation, where one of the 2 sections of pads occupies on each sidewall at the opposite end of the tunnel fans. Sidewalls below the curtains had a rigid foam insulation (R7.5, 1.32 m 2 C/W; unit area thermal resistance), corrugated steel siding, and plywood interior. Four equally spaced exhaust fans (91 cm or 36 in. diameter) were mounted in the north sidewal=l, whereas 14 cooling fans combined with low-pressure misting foggers were placed along the south curtain openings in the natural ventilated houses. None of the houses had sidewall air inlets. The top 10-cm sections of the air inlets in the tunnel houses were left open even when the sliding doors were closed, whereas the top 1-cm section of the south curtain served as air inlets in the cold season in naturally ventilated houses. The tunnel houses had 10 exhaust and cooling ventilation fans (120 cm or 48 in. diameter) at the east end of the houses. Air speeds during summer in tunnel houses, when all tunnel fans operated, were around 2.0 m/s (400 fpm) within 30 m (100 ft) of the fan area, and gradually decreased toward the

3 Liang et al.: BROILER HOUSE RETROFIT 213 Table 1. Housing characteristics of the 4-house test farm before farm renovation Item House 1 House 2 House 3 House 4 Sidewall Roof/ceiling Ventilation/cooling Control both sidewalls Extruded polystyrene in roof line, R = 1.76 m 2 C/W Natural ventilation when possible; 4 exhaust fans and 14 cooling fans with misting foggers Commercial 6-stage controller for fans north sidewall, pads and curtain on south sidewall Extruded polystyrene in roof line, R = 1.76 m 2 C/W Ten tunnel fans for exhaust and cooling Self-designed experimental controller for fans both sidewalls Cellulose over vapor barrier, R = 3.35 m 2 C/W Natural ventilation when possible; 4 exhaust fans and 14 cooling fans with misting foggers Commercial 6-stage controller for fans north sidewall, pads and curtain on south sidewall Cellulose over vapor barrier, R = 3.35 m 2 C/W Ten tunnel fans for exhaust and cooling Self-designed experimental controller for fans inlet area. All houses were equipped with pilotignited brooders and space furnaces of the same total supplemental heating capacity. During renovation, drop ceilings were added in the 2 open-truss houses with loose fill insulation in the attic to match the R value of 3.35 m 2 C/W in the 2 original drop-ceiling houses. All houses were converted to solid-sidewall (R = 1.94 m 2 C/W) with sidewall inlets, tunnelventilated houses with eight 1.27 m (50 in.) or 1.2 m (48 in.) diameter tunnel fans located at the west end and four 0.9 m (36 in.) exhaust fans on the north side walls, and 2 sections of recirculating evaporative cooling pads (21 m 1.2 m 15 cm) on both side walls on the east end. Air velocity during tunnel ventilation with all tunnel fans in operation averaged 2.5 m/s (500 fpm). Programmable environmental controllers (40-stage) were used in all houses. After renovation, each house contained 18 direct-ignite 12 kw (40,000 BTU/h) infrared radiant brooders to provide supplemental heat. Production Management Practices Chicks and feed were furnished by the integrator as part of the growing contracts for the flocks. Commercial pan feeders and nipple drinkers were used in all houses. Before renovation (between ), average flock market age was 41 d (ranging between d) and average chick placement was 22,700 per house. After renovation (between ), average flock market age was 52 d (ranging between d) and average chick placement was 19,300 per house. The average total BW sold per flock increased from 43,990 kg before renovation to 59,650 kg after renovation, indicating an increased bird density. Average BW of market birds from 2004 to 2008 ranged from 1.8 kg (3.9 lb) to 3.7 kg (8.2 lb). Partial house brooding was used for a period of 10 to 14 d before renovation, and 7 to 12 d after renovation. The birds had ad libitum access to feed and water throughout the entire growth periods. The lighting program followed the recommendation of the integrator. Before renovation, lighting was a combination of natural daytime light and incandescent artificial lights. After renovation, birds in all houses were raised under incandescent light before light bulbs were replaced with more energy-efficient lamps. These include cold cathode fluorescent light, compact fluorescent lights with different Kelvin ratings installed in 2008 for testing purposes. Internal air temperature over the growth periods was controlled to meet integrator recommendations. Before renovation, it started initially at 29.4 to 30.5 C and decreased about 2.8 C/ wk until the birds reached 4 wk of age. Summer cooling, by misting foggers in the conventional houses and by experimental evaporative cooling pads in the tunnel houses, was initiated at the internal air temperature of 27.2 C [10]. After renovation, internal air temperature was initially 33.0 to 33.6 C and decreased about 4 C during the first week, and 2.3 C/wk until the birds reached 4 wk of age. Summer cooling was

4 214 JAPR: Research Report achieved by the tunnel ventilation and recirculating evaporative cooling. Measurement and Analysis Live production parameters, such as FCR, adjusted feed conversion, livability, and ADG of 12 flocks before and 12 flocks after renovation, were compared with the overall improvements as a result of the combined gain of continual strain improvements, improved diet or nutrition program, and advances of housing technologies using a t-test [11]. As older birds naturally have a higher ADG, ADG up to a similar age for the pre- and postretrofit flocks were calculated. The ADG of preretrofit flocks were calculated based on processing plant weights at market ages, averaging 41 d. The ADG of postretrofit flocks were calculated based on live BW at 41 d, recorded by the bird scales in the houses. For postretrofit flocks, 3.1% was deducted from the 41-d scale weights to compensate for live shrink. The rates of the live shrink for broilers held without feed for 8 to 24 h varied between 0.18 and 0.6% (mean of 0.39%) of the bird s BW per hour of feed withdrawal [12, 13, 14]. The 3.1% used for compensation was a multiplication of 0.39% and 8 h of feed withdrawals, which was a common practice before retrofit. Actual FCR were difficult to compare between the younger market ages of flocks preretrofit and the older market age of flocks postretrofit. Therefore, FCR were adjusted to BW of 2.5 kg (5.5 lb) by increasing 1 point of FCR for each 7 points of BW increase (equivalent to 0.07 lb). Between 12 and 15 points of FCR are typically lost for 1 lb of BW gain [15] [16]; this adjustment is a typical industry practice to standardize FCR to a common weight for comparison purposes. To elucidate the production response improvement solely as a result of housing improvement, differences of means of the above parameters were derived by subtracting the industry live production performance that matches the weight categories of the flocks raised in the corresponding years [17] and compared using a t-test [11]. Data of broiler live performance of major US broiler companies, compiled by AgriStats [17], were used as benchmark parameters of the corresponding weight category and year. RESULTS AND DISCUSSION Comparison of Broiler Growth Responses Before and After Farm Renovation Average daily growth rates (up to 41 d) after farm renovation were higher than those before renovation (P < ; Figure 1 and Table 2). However, it was unclear to what extent the factors of strain or management contributed to this improved weight gain over the 4-yr period. Despite raising heavier birds after farm renovation, cumulative mortality rates at actual market age were not significantly different from those preretrofit (P = 0.062; Table 2 and Figure 2). Adjusted FCR to a common BW of 2.5 kg were 2.03 or 1.80 of pre- and postretrofit flocks (Table 2 and Figure 3). Adjusted FCR before renovation were significantly higher than those after renovation (P < ). The sooner birds reached the desired market size, the higher the percentage of feed consumed went to growth and muscle development instead of body maintenance. Comparison of Difference from Industry Live Performance Farm performance within each time frame was compared with industry averages generated within the same time frame by AgriStats [17] to minimize the differences in genetics, nutrition, and health attributed to time. Difference of ADG between the farm and the industry live performance of birds with corresponding BW showed that the farm under-performed before renovation ( 1.11 g/bird per day) but performed better than Figure 1. Average daily BW gains of 12 flocks before farm renovation ( ) at various market ages and 12 flocks after farm renovation ( ) at 41 d of age.

5 Liang et al.: BROILER HOUSE RETROFIT 215 Table 2. Means from the commercial 4-house farm before and after farm renovation Item ADG (g/bird per day) Mortality (%) Actual FCR Adjusted FCR 1 Preretrofit Postretrofit SEM P-value < < < Adjusted to 2.5 kg of BW. 2 Preretrofit = data collected from 2004 to 2005 before farm renovation. 3 Postretrofit = data collected from 2006 to 2008 after farm renovation. 4 Average daily BW gains of postretrofit flocks were calculated based on 41-d bird scale weights, with adjustment of shrinkage due to feed withdrawal, and so on. industry average after renovation (3.53 g/bird per day; Table 3). The industry comparison supports the belief that birds raised in modern housing reached market weights sooner than those raised in housing that did not provide uniform environmental conditions. This faster-to-market growth rate demonstrates the importance of advanced housing technologies in realizing the bird s genetic potential, allowing higher annual production throughput from the same production area on the renovated farm [5]. Cumulative mortality rates were higher than the industry average before renovation, but were lower than those at correspondent weight categories reported as industry average after renovation (Table 3). It is widely accepted that modern broiler houses equipped with environmental controllers, static pressure-controlled inlets, tunnel ventilation with evaporative cooling, and standby generators are better at achieving a uniform environment closely matching the needs of birds reared from 1 d of age to market weight. However, other factors, such as flock health (disease and vaccination), drinker management, chick quality, and so on, also contributed to the variability of mortality rates. Growth rate and livability directly influence feed conversion. Feed conversion from flocks sold before farm renovation were higher than industry average (0.024), but lower than industry average after farm renovation ( 0.036; Table 3). The calculated differences of adjusted FCR from flocks sold after farm renovation were again significantly lower than those from flocks sold before farm renovation (P < 0.001; Table 3). This study provided evidence of positive outcomes of farm retrofits for production benefits to producers and integrators. Factors such as housing, environment, management practices, and genetics are closely intertwined in the production of broilers; therefore it is difficult to recognize the full contribution of each individual factor. However, the comparison to pertinent industry averages does support the positive effect of improvements in housing technology. Figure 2. Cumulative mortality rates of 12 flocks at various market ages before ( ) and after ( ) farm renovation. Figure 3. Adjusted feed conversion to BW of 2.5 kg of 12 flocks at various market ages before ( ) and after ( ) farm renovation.

6 216 JAPR: Research Report Table 3. Mean differences from industry live performance of birds with corresponding market weight categories and years Item ADG (g/bird per day) Mortality (%) Actual FCR Adjusted FCR 1 Preretrofit Postretrofit SEM P-value < Adjusted to 2.5 kg of BW. 2 Preretrofit = data collected from 2004 to 2005 before farm renovation. 3 Postretrofit = data collected from 2006 to 2008 after farm renovation. CONCLUSIONS AND APPLICATIONS 1. Comparing to the flocks sold preretrofit, ADG of flocks raised postretrofit were 5.6 g/bird per day higher up to 41 d age, with similar cumulative mortality and better adjusted FCR (0.23) over a 4-yr span. This improvement was a combined result of continual strain and nutrition improvements and advances of housing technologies. 2. Compared with the industry average under the same weight categories during a similar time frame, live performance on the renovated farm was better, with higher ADG and lower adjusted FCR. These performance parameters on the preretrofit farm were worse than the industry average, with lower ADG and higher adjusted FCR. Modern broiler housing with better environmental control increased production efficiency after eliminating the contribution from broiler strain improvement and the associated nutritional and health program. 3. Better environmental control as a result of broiler housing retrofit is crucial in recognizing genetic and nutritional potential. Farm retrofits of older houses ensure competitiveness and higher returns of the producers. REFERENCES AND NOTES 1. Flachowsky, G Efficiency of energy and nutrient use in the production of edible protein of animal origin. J. Appl. Anim. Res. 22: USDA Statistical highlights of US Agriculture Livestock. Economic Research Service, USDA. Accessed Mar. 7, USDA Poultry Production and Value: 2011 Summary. National Agricultural Statistics Service, USDA. Accessed Mar. 7, usda/current/poulprodva/poulprodva pdf. 4. Donohue, M How poultry breeding companies help improve broiler industry efficiency. Cobb Business Focus. Accessed Nov Cunningham, D. L Contract broiler grower returns: A long-term assessment. J. Appl. Poult. Res. 6: Campbell, J., G. Simpson, and J. Donald Poultry house energy retrofits for fuel and cost savings. The Poultry Engineering, Economics and Management Newsletter, Issue # 43, Auburn University. 7. Hoff, S Assessing air infiltration rates of agricultural use ventilation curtains. Appl. Eng. Agric. 17: Liang, Y., G. T. Tabler, S. W. Watkins, H. Xin, and I. L. Berry Energy use analysis of open-curtain and enclosed systems at a commercial-scale broiler research farm. Appl. Eng. Agric. 25: Berry, I. L., R. C. Benz, and H. Xin A controller for combining natural and mechanical ventilation of broilers. ASAE Technical Paper No American Society of Agricultural Engineering, St. Joseph, MI. 10. Xin, H., I. L. Berry, T. L. Barton, and G. T. Tabler Feed and water consumption, growth, and mortality of male broilers. Poult. Sci. 73: JMP Pro SAS Institute Inc., Cary, NC. 12. Veerkamp, C. H Fasting and yield of broilers. Poult. Sci. 65: Buhr, R. J., J. K. Northcutt, C. E. Lyon, and G. N. Rowland Influence of time off feed on broiler viscera weight, diameter, and shear. Poult. Sci. 77: Fletcher, D. L., and A. P. Rahn The effect of environmentally modified and conventional housing types on broiler shrinkage. Poult. Sci. 61: Cooper, M Cobb-Vantress Inc., Fayetteville, AR. Personal communication. 16. Price, L Sanderson Farm Inc., Laurel, MS. Personal communication. 17. AgriStats Allied Live Production General Run. AgriStats Inc., Fort Wayne, IN.