Heat and Moisture Production of Broilers

FLAVOR COMPARISON

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REFERENCES Batzer, O. F., A. T. Santoro, M. C. Tan, W. A. Landmann and B. S. Schweigert, 1960. Meat flavor chemistry: Precursors of beef flavor. J. Agr. Food Chem. 8: 498-501. Batzer, O. F., A. T. Santoro and W. A. Landmann, 1962. Identification of some beef flavor precursors. J. Agr. Food Chem. 10: 94-96. Beatty, C. H., R. D. Peterson and R. M. Bocek, 1963. Metabolism of red and white fiber groups. Amer. J. Physiol. 204: 939-942. Crocker, E. C , 1948. Flavor of meat. Food Res. 13: 179-183. Froning, G. W., M. H. Swanson and H. N. Benson, 1960. Moisture levels in frozen poultry as related to thawing losses, cooking losses, and palatability. 1. Chicken broilers. Poultry Sci. 39: 373-377. Hurley, W. C , O. J. Kahlenberg, E. H. Funk, L.

Heat and Moisture Production of Broilers 2. WINTER CONDITIONS1 J. W. DEATON AND F. N. REECE U. S. Department of Agriculture, State College, Mississippi 39762 AND

Department

C. W . BOUCHILLON of Mechanical Engineering, Mississippi State University, State College, Mississippi 39762 (Received for publication April 7, 1969)

P

OULTRY-HOUSE ventilation systems must be designed to maintain optimum conditions over a wide range of climatic conditions. The ventilation requirements 1

Trade names are used in this publication solely to provide specific information. Mention of a trade name does not constitute a guarantee of warranty by the U. S. Department of Agriculture and does not signify that the product is approved to the exclusion of other comparable products.

for summer conditions are vastly different from those for winter; however, the same ventilation system must be adaptable for both seasons. In summer, when important functions of ventilation are to limit house temperatures during the hot part of the day and to maintain optimum conditions by removing heat and moisture, the required ventilation rate may be as high as ISO liters per minute per bird. In winter,

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G. Maharg and N. L. Webb, 1958. Factors affecting poultry flavor. 1. Inorganic constituents. Poultry Sci. 37 : 1436-1440. Krum, J. K., 1955. Truest evaluations in sensory panel testing. Food Engr. 27(7): 74-83. Little, A. D., Inc., 1958. Flavor Research and Food Acceptance. Reinhold Publishing Corp., New York. Peterson, D. W., 1957. The source of chicken flavor. Chemistry of Natural Food Flavors, p. 167. The Quartermaster Food and Container Institute for the Armed Forces, Chicago, 111. Pippen, E. L., A. A. Campbell and I. V. Streeter, 1954. Flavor studies: Origin of chicken flavor. J. Agr. Food Chem. 2 : 364-367. Pippen, E. L., and A. A. Klose, 1955. Effects of ice water chilling on flavor of chicken. Poultry Sci. 34: 1139-1146. Pippen, E. L., and M. Nonaka, 1963. Gas chromatography of chicken and turkey volatiles: The effect of temperature, oxygen, and type of tissue on composition of the volatile fraction. J. Food Sci. 28: 334-341. Spencer, J. V., 1961. Factors associated with the flavor of poultry meat. Ph.D. Thesis, Purdue University, Lafayette, Indiana.

experimental work. Appreciation is extended to the Department of Foods and Nutrition for the use of its facilities and for assistance in conducting the taste panels.

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J. W. DEATON, F. N. REECE AND C. W.

OBJECTIVE The objective of this study was to obtain heat and moisture production, and associated performance of broiler chickens grown on litter under winter conditions typical of the major broiler producing area of the Southeast U. S. EXPERIMENTAL PROCEDURE Approximately 2,100 broiler chickens were reared in a windowless poultry house located at State College, Mississippi under actual winter conditions. The husbandry practices used for the winter test were essentially the same as for the summer test as reported by Reece et al. (1969). Important points were: 1) Stock: Straight-run, commercial broiler chicks from Mycoplasma gallisepticum-iree flock. 2) Diet: First 6 weeks—23.S percent protein, 2,381 kilocalories/kilogram of productive energy. Last 2 weeks—21.0 percent protein, 2,424 kilocalories/kilogram of productive energy. 3) Vaccination: Combination B 1 type Newcastle, and Massachusetts and Connecticut types bronchitis at 10 days of age. 4) Light: Continuous at 8.1 lux. Description of the house, pen arrangement, and instrumentation for measuring heat and moisture removed from the house in the ventilation air were the same as for the summer test reported by Reece et al. (1969). The major points on instrumenta-

tion for measuring heat and moisture removed from the house were: dry-bulb temperatures were measured with nickle resistance-type sensors located in the air supply and exhaust ducts. The sensors were connected to a recorder, as described by Reece and Deaton (1968), so both supply and exhaust temperatures were recorded on the same chart. Dewpoint temperatures of supply and exhaust air were measured by Honeywell Dewprobes connected to a second recorder. The continuous records obtained with the Dewprobes were cross-checked at 4-hour intervals with a Cambridge Systems hygrometer connected to a third recorder. Ventilation rate was measured by continuously recording the fan speed, which was calibrated in liters of air per minute by means of a standard pitot-tube traverse taken at mid-point in a 0.61- by 0.61-meter duct 12 meters long attached to the inlet of the fan. The dry-bulb and dewpoint temperature differences and ventilation rate data were then converted to sensible heat and latent heat (moisture) production by means of digital computer program using a psychometric subroutine devised by McKie (1967). The chicks were brooded in a conventional manner for the first 3 weeks. Collection of heat and moisture data was started at the beginning of the fourth week. At that time, all supplementary heat used during brooding was turned off, and subsequently the house temperature was maintained at 15.6° ± 2.8°C. by varying the ventilation rate with a variable speed fan controlled by a proportional thermostat. RESULTS AND DISCUSSION Pertinent data associated with sensible heat and latent heat (moisture) production were summarized by weekly periods and are presented in Table 1. The climatic conditions during the test were typical for mid-winter in the South.

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when important functions are to maintain optimum temperatures by conservation of heat and to remove excess moisture, the ventilation rate may drop to 10 percent or less of the summer requirements. Data such as those by Ota et al. (1961) and Longhouse et al. (1960) are required for rational design of poultry house ventilation systems. These data should be supplemented with data covering a wide range of conditions.

BOUCHILLON

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BROILER HEAT AND MOISTURE PRODUCTION TABLE 1.—Test conditions and chicken performance for a study to determine heat and moisture production of broilers reared in a windowless house in the winter in Mississippi

Age period, weeks (Dec. 23, 1968 to Jan. 27, 1969) Fifth 4 to 5

Sixth 5 to 6

Seventh 6 to 7

Eighth 7 to 8

13.9 7.2 10.7 18.2 7.5 0.8 8.3 2,052 1,294

12.2 5.6 8.9 17.3 8.4 0.0 8.4 2,046 1,469

Average Average Average Average Average Average Average Average Average

maximum inlet dry-bulb temperature, °C minimum inlet dry-bulb temperature, °C. inlet dry-bulb temperature, °C. exhaust dry-bulb temperature, °C. temperature difference, (exhaust-inlet), °C inlet dewpoint temperature, °C. exhaust dewpoint temperature, °C. number of birds weekly weight, grams/bird*

11..7 3..3 8..3 16..2 7..9 - 1 . .2 8.4 2,066 500

5.6 0.0 3.7 15.8 12.1 -5.7 10.3 2,063 758

10.0 1.7 4.7 14.8 10.1 -5.4 5.8 2,058 1,054

Average Average Average 465 697 929

ventilation rate, l./min./bird 20.7 ventilation rate, l./min./kilogram 37.7 litter moisture, percent (wet basis) sq. centimeters/bird Severely caked, wet surface sq. centimeters/bird Moderately caked sq. centimeters/bird Damp, friable

16.7 22.0

26.9 25.6 (

41.3 31.9 Average41.3a** 41.5a 29.8b

38.5 26.2

* Average weight at 8 weeks was 1,597 gms./bird. Feed efficiency for the 8-week period was 2.38 gms. feed/gm. of body weight. ** Differing letters denote significance at the .05 level of probability.

The lowest ouside temperature was — 12°C, which occurred when the chickens were 4.5 weeks of age. The average weekly dry-bulb temperature measured at the inlet to the house ranged from 3.7°C. during the fifth week to 10.7°C. during the seventh week. The 1S.6°C. house temperature was arbitrarily selected on the basis of prior experience in the house. It had been found that this temperature could be maintained without supplementary heat, and that ammonia would not be a problem. The rather poor feed efficiency of 2.38 gms. feed/gm. of body weight can be attributed to the low house temperature, although good bodyweight gains were obtained at this temperature (Table 1). As indicated in Table 1, litter moisture does not appear to be a consistent indicator for litter conditions, since the litter moisture for the 465 sq. centimeter/bird density was not different from that for the 697 sq. centimeter/bird density, but the litter was in much worse condition at the high bird density. The reason for this is that mixing

of the manure and litter is poor under crowded conditions. The result is a caked condition with dry, fresh litter next to the floor, and fresh, wet manure on the surface. The ventilation rate, which was automatically modulated to maintain the house temperature at 15.6° ± 2.8°C, varied between 7.5 and 45.2 l./min./bird as the outside climatic conditions varied between - 1 2 ° C . and 12.8°C. The sensible and latent heat production data for the broilers grown under conditions given in Table 1 are given in Table 2. In comparing the summer data reported by Reece et al. (1969) with the winter data in Table 2, it was found that the total heat was slightly less for winter than for summer. However, there were major differences in the sensible heat and latent heat between summer and winter. The latent heat ranged from 28 percent to 87 percent greater in summer than in winter, with the greatest difference during the eighth week. These differences are consistent with water consumption data reported by Winn and Godfrey (1967).

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Fourth 3 to 4

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J. W. DEATON, F. N. REECE AND C. W. BOUCHILLON

TABLE 2.—Sensible heat (SH) and latent heat (LH) production for broiler chickens on Utter in windowless housing in winter in Mississippi under conditions given in Table 1 Age period, week Fifth

Sixth

Seventh

Eighth

SH, ventilation air, calories/hr./bird SH, wall+ceiling losses,* calories/hr./bird LH,** ventilation air, calories/hr./bird Total heat, calories/hr./bird

2,674 544 2,374 5,592

3,261 723 3,276 7,260

4,576 527 3,702 8,805

5,058 441 4,201 9,700

5,267 501 4,354 10,122

SH, ventilation air, calories/hr./gram SH, wall+ceiling losses,* calories/hr./grami LH,** ventilation air, calories/hr./gram Total heat, calories/hr.gram

5.35 1.09 4.75 11.19

4.30 0.95 4.32 9.57

4.34 0.50 3.51 8.35

3.91 0.34 3.25 7.50

3.58 0.34 2.97 6.89

* Heat losses calculated for thermal conductivity based on inside-outside temperature difference, 15.2 centimeters of glass fiber ceiling insulation and 9.2 centimeters of glass fiber wall insulation in house decribed by Reece et al. (1969). ** Based on latent heat of 574.4 calories/gram of water.

The sensible heat ranged from 19 percent to 45 percent greater in winter than summer, with the greatest difference during the. eighth week. Ammonia was not a problem during the test period, with concentrations remaining less than 10 p.p.m. The house was comparatively free of dust during the test period. SUMMARY Approximately 2,100 broilers were reared in a well-insulated windowless house under typical winter conditions in Mississippi. Sensible and latent heat production data were obtained for the 3- to 8-week growth period, along with associated data on growth rate, feed consumption, litter conditions, and ventilation rate required to maintain a uniform house temperature. Total heat removed from the house increased from 5,592 calories/hr./bird during the fourth week to 10,122 calories/hr./bird during the eighth week. Sensible and latent heat increased at approximately the same rate during the growth period. Compared to summer heat production data, the winter total heat was found to be slightly less than for summer, but the summer latent heat was almost double that for winter during the eighth week. The winter sensible heat was almost 50 percent greater

than that for summer during the eighth week. At 465 sq. centimeters/bird, poor litter conditions developed which appear to be more a function of the mixing of the litter than the moisture content. When no supplementary heat is available, it was necessary to vary the ventilation rate between 7.5 and 45.2 l./min./bird in order to maintain a house temperature near 15.6°C. under typical winter conditions in Mississippi. REFERENCES Longhouse, A. D., H. Ota and W. Ashby, 1960. Heat and moisture design data for poultry housing. Agricultural Engineering, 4 1 : 567. McKie, W. T., 1967. Psychrometric data subroutine for computer implementation. Private correspondence. Ota, H., and E. H. McNally, 1961. Poultry respiration calorimetric studies of laying hens—Single Comb White Leghorns, Rhode Island Reds, and New Hampshire X Cornish Crosses. USDA, ARS 42-43. Reece, F. N., and J. W. Deaton, 1968. Recording dual data points with single-pen recorders. Agricultural Engineering, 49: 146. Reece, F. N., J. W. Deaton and C. W. Bouchillon, 1969. Heat and moisture production of broilers. 1. Summer conditions. Poultry Sci. 48 :1297-1303. Winn, P. N., Jr., and E. F. Godfrey, 1967. The effect of temperature and moisture on broiler performance. University of Maryland, Agr. Exp. Sta. Bull. A-153.

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Fourth