1、4720 (RP-1044) Heat and Moisture Production of Poultry and Their Housing Systems: Pullets and Layers H. Justin Chepete, Ph.D. Hongwei Xin, Ph.D. Member ASHRAE Manuel C. Puma, Ph.D. Richard S. Gates, Ph.D. Member ASHRAE ABSTRACT Heat and moisture production rates (He MP) of modern pullets and laying
2、hens were measured using large-scale indi- rect calorimeters that mimic commercial production settings. The experimental birds were Hy-Line W-36 strain at 1-5, IO, 21, 37, and 64 weeh of age and Hy-Line W-98 strain at 1-5 weeks of age. Total HP (THP) was partitioned into latent and sensible HP (LHe
3、SHP) at bird level (excluding moisture evaporation from feces) or room level (including fecal mois- ture evaporation from feces). The W-98 and W-36 pullets reached their metabolic peak at about 10 and 14 days of age, respectively. The W-98pullet showed higher THP than the W- 36 counterpart. Modernpu
4、llets have significantly higher THP (12% to 37%; P 0.05) than pullets of 20 to 50 years ago. At the initial stage of egg production, the W-36 layers showed 12% higher THP than that predicted by the CIGR (1999) model, and the diference diminished with time. Evaporation of fecal moisture elevated room
5、 LHP by 8% to 38% (average 14%) during lightperiod and by 21% to 79% (average 43%) during darkperiod but reduced room SHP by 4% to 17% (aver- age Il%) during light period and by 14% to 33% (average 22%) during dark period with reference to bird LHP or SHl? All HP responses in the dark were significa
6、ntly (P and SHP of the bird or room to bird body mass were established. Results of this studyprovide an updated thermal load database for design and operation ofpoultry housing ventilation systems, as well as the latest bioenergetics of modern pullets and hens. I NTROD U CTION Heat and moisture prod
7、uction rates (HP, MP) of animals and their surroundings are the basis for eficient design and operation of environmental control systems of production facilities. The magnitude of HP and MP is subject to influence of animal genetics, nutrition, housing type, production equip- ment, and management pr
8、actices, all of which have witnessed significant advancements over the years (Reece and Lott 1982a, 1982b; Gates et al. 1996; Xin et al. 1998). For instance, Havenstein et al. (1991) reported a 350% increase in growth rate of modem broiler chickens compared with those in 1957. Sensible HP (SHP) and
9、MP of a litter floor-type broiler house was found by Reece and Lott (1982a) to be, respectively, much lower and higher than SHP and MP of the bird reported from earlier calorimetric studies in the literature (Longhouse et al. 1960). Light or darkness has been shown to have significant impact on HP a
10、nd MP of poultry (Riskowski et al. 1977; Zulovich et al. 1987; Xin et al. 1996). An extensive literature review of HP and MP of poultry (pullets, layers, broilers, and turkeys) and their housing systems recently performed by Chepete and Xin (2002) revealed that most HP and MP data in the literature
11、are 20 to 50 years old, and that considerable gaps exist in the data for certain species or production stages. For example, the only HP and MP data documented for pullets covered the growth period of 1 to 7 weeks of age (Zulovich et al. 1987), and there were no data for pullets and layers between 7
12、and 33 weeks of H. Justin Chepete is a former graduate research assistant, Hongwei Xin is a professor, and Manuel C. Puma is a former post-doctoral research associate in the Agricultural and Biosystems Engineering Department, Iowa Sate University, Ames, Iowa. Richard S. Gates is a professor and chai
13、r in the Biosystems and Agricultural Engineering Department, University of Kentucky, Lexington, Ky. 286 02004 ASHRAE. age. The result further confirmed the need to systematically update HP and MP characteristics of modern poultry for design and operation of environment-controlled poultry hous- ing,
14、as had been suggested by Gates et al. (1996), Xin et al. (1998), and ASHRAE (2001). This study was a part of the effort toward accomplishing the aforementioned need. The specific objectives of this study were (1) to measure HP and MP of pullets and layers using large-scale indirect calorimeters that
15、 mimic commercial production settings with respect to thermal environment, stocking density, feeding and water scheme, photoperiod, and manure handling practices; (2) to compare the results with those currently available in the literature; (3) to evaluate the contribution of fecal and surrounding mo
16、isture sources to room MP by separately quantifying latent HP (LHP) of bird vs. room; and (4) to establish functional relationships between HP or MP and bird body mass. MATERIALS AND METHODS Experimental Facility and Bird Handling An indirect calorimeter system, consisting of four calo- rimeter cham
17、bers (1.5 W x 1.8 DI x 2.4 HI m) (Xin and Harmon 1996; Xin et al. 1998), was used for this study (Figure 1). In particular, the gas (O2 and CO2) analyzers were cali- brated daily throughout the experimental periods to ensure an HP measurement system uncertainty of h0.5 watt per chamber (65 watt HP o
18、utput per chamber). In each trial performed for both pullets and layers, two randomly selected chambers had oil pans placed under the cages to submerge the feces, thereby preventing interference of fecal moisture evaporation with measurement of HP and MP from birds only. The other two calorimeters h
19、ad no oil in the catching pans (as would be the case with manure belt), and, thus, MP included contribution from both birds and feces. Manure was removed from all chambers twice weekly, after which oil was replenished to ensure complete submergence of feces. Birds were group- weighed weekiy througho
20、ut the trials, so that regression models could be established and used for calculation of specific HP and MP. Bird mortality was continuously monitored and excluded from calculation of total body mass for determination of specific HP and MP. The commercially practiced management schemes (feeding, li
21、ghting program, temperature, stocking density, and manure handling) were followed throughout all the trials, as described below. At the end of each trial, the calo- rimeter chamber system was cleaned, disinfected, maintained (as needed), and unoccupied for a week or longer before the next trial. Mea
22、surements of HP and MP Pullets. Two separate groups of Hy-Line W-36 and W-98 pullets were measured for the pullet study, each covering a zero- to five-week growth period. Each group consisted of 720 chicks. Upon delivery from the commercial hatchery to the measurement laboratory, the chicks were gro
23、up-weighed and Fresh Air Supply Bleed Valve Needle Valve Figure 1 A schematic representation of the indirect calorimeter system used in the present study. ASHRAE Transactions: Research 287 randomly allocated to the four indirect calorimeter chambers. Each chamber had a movable supporting stand with
24、nine cages (55 LI x50 W x 41 HI cm each). Twenty-day-old chicks were initially allocated to each cage and were thinned down to 15 and 1 O at the start of weeks 3 and 4, respectively, which led to 180,135, and 90 birds per chamber, respectively. These bird numbers ensured sufficient changes in air co
25、mposition (O, and CO2) of the calorimeter chambers for the instruments to make accurate measurements. Thermoneutral (TN) air temperature was maintained in all chambers during the growth and measurement period. Specifically, air temperature inside the calorimeters was kept at 32C during the first two
26、 days and was reduced by 1 “C every three days thereafter until 2 1“C, where it remained constant. The corresponding relative humidity (RH) ranged from 35% to 50% throughout the trial. The chicks were provided contin- uous lighting for the first two days, then 15hL:9hD until two weeks of age and, th
27、ereafter, 12hL:12hD until the end of the trial at five weeks of age. Light intensity was 16-2 1 lux for the first two days and 5-1 1 lux for the remainder of the trial. Free access to feed and water through nipple drinkers was provided. A prestarter ration was fed for the first week, followed by a s
28、tarter ration (Table 1). To bridge gaps in the literature data, HP and MP of W-36 pullets at ten weeks of age were measured, involving a total of 324 birds. The pullets were group-weighed and randomly allo- cated to the calorimeters with 81 birds per chamber (9 birds per cage). The measurement laste
29、d for four weeks. The room temperature was 22C during the first week, 28C during the second and part of the third week, and back to 22C during part of the third and the fourth week. Light intensity was 5-1 1 lux throughout the trial period. RH varied from 35% to 50% the entire time. Photoperiod was
30、12hL:12hD. The birds had free access to feed (Table 1) and nipple drinkers. Laying hens. HP and MP of W-36 laying hens were measured for 21, 37, and 64 weeks of age to reflect various production stages of the hens. Each age group was studied over a three-week period. The temperature regimen was 24C
31、(TN), 30C (warm), and back to 24C during the first, second, and third week, respectively. Only data associated with the first week are presented in this paper. Each age group involved a total of 252 hens procured from local commercial farms. The hens were randomly allocated to the calorimeter chambe
32、rs, 63 birds per chamber, 7 hens per cage. RH ranged from 35% to 50% for the entire measurement period. Light scheme of 13hL:llhD, 16hL:8hD, and 16hL:ghDat anintensityof5-11 lux was used, respectively, for 21-, 37- and 63-week old hens. Eggs were collected twice daily to minimize breakage that would
33、 otherwise interfere with MP measurement. Free access to feed (Table 1) and water through nipple drinkers was provided. Data Analysis and Presentation For each 24-h period of the trials, data were separated into dark and light periods and their time-weighted averages (TWA) determined. Total HP (THP)
34、 was further partitioned into latent HP (LHP) and SHP of bird or room, as described above. The data were subjected to analysis of variance using statistical analysis software. Regression models were devel- oped to relate the HP responses to body mass (M of the bird. Table 1. Dietary Ingredients (“YO
35、, Unless Otherwise Noted) of Feed Used in the Study W-36 and W-98 Pullets (0-35 d) W-36 Birds Prestarter Dietary Content Ration Starter Ration 10 wk 21 wk 37 wk 64 wk ME (MJkg) 12.20 12.20 12.70 11.80 11.60 12.20 Crude protein 21.00 20.20 16.50 18.00 14.82 15.80 Crude fat 3.10 3.30 3.60 NIA 2.77 NIA
36、 Crude fiber 3.50 4.10 3.80 N/A 2.37 NIA Calcium 1 .O4 1 .O4 1 .O4 4.25 4.42 4.12 Total phosphorus 0.75 0.65 0.66 0.76 0.47 NIA Available phosphorus 0.52 0.43 0.47 0.57 NIA 0.31 Sodium 0.18 0.18 0.16 0.21 0.21 0.18 Total Iysine 1.19 1.11 0.83 NIA 0.80 NIA Lysine NIA NIA NIA 1 .O3 NIA 0.82 Methionine
37、 NIA NIA NIA 0.51 N/A 0.36 Total methionine 0.50 0.48 0.39 NIA NIA N/A Methionine and Cystine 0.86 0.82 0.69 NIA 0.61 NIA Choline (mglb) NIA NIA NIA NIA NIA 518.50 N/A = Information not available 288 ASHRAE Transactions: Research The HP and MP data of pullets during the first two days inside the cal
38、orimeter chamber and the first day for the 10- to 64-week old birds were excluded in the development of the models as the birds were acclimating to the new environment. Data collected during cleaning and weighing of the birds were also excluded from analysis. RESULTS AND DISCUSSION Body mass (Mkg) a
39、nd age (D day) of the birds had the following functional relationships: For W-98 pullets (3 5 D I35), M = 1.46 x lo4 D2 + 3.71 x low3 D + 0.0295 (R2= 1.000) (1) For W-36 birds (3 ID I 70), M =-3.00 x lo4 D3 + 0.0004D2 - 0.00040 + 0.0463 (R2 = 0.999) (2) For W-36 birds (70 ID 5448), M=910-0-8x 1(T5D2
40、 + 0.02180 - 0.3533 (R2 = 1.000) (3) These relationships are shown in the graphs of THP, LHP, and SHP as a function of M. The THP, LHP, SHP, and respiratory quotient (RQ, CO2/ 0,) at bird and room levels (LHP and SHP) for light, dark, and TWA conditions at various growth and production stages are su
41、mmarized in Table 2. There was no significant difference in THP between the calorimeters with or without oil pans (i 0.52). Thus, THP values from all four calorimeters were pooled in the analysis. The THP regression models developed had the form of THP = ah# and are presented in Table 3. Selection o
42、f the THP model form was based on the physiological phenomenon that metabolic rate is directly proportional to Mraised to a certain power or metabolic mass unit (Brody 1945). The regression models for LHP and SHP were quadratic polynomials in the form of LHP or SHP (W/kg) = aM2 + bM+ c and are prese
43、nted as bird or room values in Tables 4 and 5, respectively. Although THP remains unchanged under a given TN condi- tion, the partitioning of THP into SHP and LHP can be greatly influenced by the contribution of ambient moisture and heat sources. This explains the use of polynomial equations to desc
44、ribe the relationships between the SHP or LHP and bird body mass. The numerical differences in LHP or SHP between the table values and those derived from regression models were inevitable. For design purposes, use of the table values (e.g., Table 2) is recommended, whenever possible. The contributio
45、n of feces and other surrounding elements to the elevation of room LHP and reduction of room SHP can be noted for various growth and production stages in Figures ASH RAE Transactions: Research 2 and 3. While bird LHP and SHP provide insights into delin- eation of thermoregulation, room LHP and SHP p
46、rovide a more realistic basis for design and operation of the housing ventilation system. Metabolic Peak Period During the initial stage of growth, specific THP of the pullets increased progressively and reached its peak at a certain age (Figure 2 for W-98 and Figure 3 for W-36). This period is know
47、n as the “metabolic peak period“ (Brody 1945). The W-98 pullet reached the metabolic peak (17.8 Wkg) at about ten days of age, while the W-36 counterpart reached the peak (15.4 Wkg) at about 14 days of age (Table 2). This result parallels a report from the industiy that the W-98 strain reaches matur
48、ity at an earlier age than the W-36 strain. Specif- ically, W-98 birds begin egg production at 16 to 17 weeks of age, as compared with 18 to 19 weeks for W-36 hens (Hy-Line 2000-2001). During this peak period, THP of the W-98 pullet rangedfiom 16.Oto 17.8 W/kg,ascomparedwithTHPof 12.8 to 15.4 Wkg fo
49、r the W-36 pullet. Figure 3 shows a somewhat higher metabolic peak for the W-36 pullet. This resulted from a curve-fitting artifact while making the two curves meet. However, for W-98 pullets (Figure 2), the two curves fit well. The LHP steadily increased to a maximum by six days of age for both W-98 and W-36 pullets and then declined, while SHP increased sharply for both species prior to the metabolic peak. This may have resulted from increased metabolic rate as the pullets physiologically develop. SHP of the W-98 pullets continued to rise slightly after metabolic
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