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Effect of Temperature and Dietary Energy on Layer Performance1
Effect of Temperature and Dietary Energy on Layer Performance1 ALFREDO PEGURI and CRAIG COON2 Department of Animal Science, University of Minnesota, St. Paul, Minnesota 55108 (Received for publication December 18, 1989)
1991 Poultry Science 70:126-138 INTRODUCTION
Payne (1964; 1966a,b; 1967) demonstrated that feed intake decreases as environmental temperatures increase. Experiments conducted to evaluate the effect of temperature on ME intake have shown that hens have the ability to adjust feed intake to supply ME needed for maintenance and production (Davis et al., 1972, 1973; Smith and Oliver, 1972a,b; Wilson et al., 1972). Morris (1968) indicated that groups of pullets offered different diets tend to adjust consumption so as to maintain the same caloric intake, although the adjustment by pullets was imperfect in most cases, as birds fed high energy diets overconsumed calories. Marsden et al. (1987) found dietary energy content had small but significant effects on egg weight and egg output in experiments in which temperature was controlled by adjusting the ventilation rate. The factors that determine energy intake need to be understood to predict energy intake with precision. The present experiment was designed to study the simultaneous effect of temperature and energy density levels on consumption of ME and
'Published as Paper Number 17,603 of the Scientific Journal Series of the Minnesota Agricultural Experiment Station. ^To whom correspondence should be addressed.
performance of laying hens at ventilation rates indicated to be optimum at each temperature in the breeders' management guide. MATERIALS AND METHODS
Fourteen hundred and forty DeKalb-XL layer hens were housed in six environmental rooms; each room contained 240 hens. The hens were randomly allotted, 2 hens per cage, with each experimental unit consisting of five cages. Six environmental temperatures were set at 16.1, 18.9, 22.2, 25.0, 27.8, and 31.1 C. The temperatures were kept constant for each room; however, changing outside ambient temperatures during the experiment produced small fluctuations of temperatures in the rooms. Temperatures were recorded daily in the morning and in the afternoon. The overall mean temperatures and standard deviations for the six rooms were 16.0 ± 1.4,19.0 ± .42, 22 ± .53, 24.6 ± .26, 27.7 ± .24, and 30.5 ± .49 C. Relative humidity was held between 50 and 60%. Ventilation rate was 47.1 L/min per bird at 16.1 C and was increased 10 L/min per bird for each degree increase in temperature. Sixty layers (six environmental units) at each temperature were fed for ad libitum consumption of corn-soybean diets (Table 1)
126
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ABSTRACT DeKalbXL White Leghorn hens 20 wk of age housed at 16.1,18.9,22.2,25.0,27.8, and 31.1 C were fed diets containing 2,645,2,755,2,865, and 2,976 kcal MEn/kg. Feed intake was 5.9 g lower (P<.05) when dietary energy was increased from 2,645 to 2,976 kcal MEg/kg and was 21.7 g lower when temperatures were increased from 16.1 to 31.1 C. The MEQ intake of hens at temperatures ranging from 16.1 to 31.1 C was 61.2 (P<05) kcal/hen per day lower in treatments with the higher temperatures. The MEQ intake of hens was also 16.7 kcal/day higher (P<.05) when energy density in the diet was raised from 2,645 to 2,976 kcal MEg/kg. Egg production was not affected by either temperature or dietary energy density. Egg weight increased .78 g (P<05) with increases in dietary energy density from 2,645 to 2,976 kcal ME^/kg and decreased 3.18 g (P<05) when temperatures were raised from 16.1 to 31.1 C. Mean body weights and body weight gains were significantly (P<05) higher in treatments with higher energy density and lower in treatments with higher environmental temperatures. Feed conversion was increased .41 g feed/g egg mass (P<05) at higher temperatures (16.1 and 31.1 Q and increased .17 g feed/g egg mass at higher energy densities (2,645 and 2,976 kcal MEj,/kg). Maintenance requirements were estimated at all temperatures. (Key words: temperature, laying hens, metabolizable energy, egg production, feed intake)
127
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 1. Percentage and calculated composition of Sets with four levels of energy fed to White Leghorn hens between 20 and 36 wk of age Ingredient and analysis
2,645 kcal/kg
2,755 kcal/kg
2,865 kcal/kg
2,976 kcal/kg
59.335 2.00
58.684 3.78
56.447 2.00 2.04 1.36 19.13 .104 .125 2.03 .065 .3 3.0 2.0 3.0 5.0 3.47 100.07
20.15 .111 .125 2.11 .065 .3 3.0 1.08 3.0 5.0 3.84 100.11
Calculated analysis MEQ, kcal/kg 2,645 Protein, % 16.37 Methionine, % .378 TSAA, % .663 Lysine, % .774 Calcium, % 3.59 Nonphytate phosphorus, % .453 Methionine, mg/therm 142.9 TSAA, mg/therm 250.67 Lysine, mg/therm 292.6 Calcium, g/therm 1.36 Nonphytate phosphorus, mg/therm 171.3 Analyzed TMBQ, kcal/kg 2,702 Analyzed CP, % 16.22
2,755 17.00 .394 .689 .807 3.74 .474 143.0 250.1 292.9 1.36 172.0 2,812 16.74
2,865 17.59 .412 .716 .839 3.89 .491 143.8 249.9 292.8 1.36 171.3 2,928 17.42
.• *
22.60 .126 .125 254 .065 .3 3.0
5.0 4.12 100.12 2,976 18.06 .434 .744 .887 4.04 .510 145.8 250.0 298.0 1.36 171.3 3,010 1851
^onnutritive filler (cellulose), Brown Co., Berlin, NH. The vitamin mix provided the following per kilogram of diet: vitamin A, 8550IU; vitamin D3,4,125 IU; vitamin E, 4 IU; menadione sodium bisulfite complex, 1.03 mg; riboflavin, 5.5 mg; niacin, 20.6 mg; pantothenic acid, 7.6 mg; folic acid, .275 mg; vitamin Bi 2 , 6.9 \lg. 3 The mineral mix provided the following in milligrams per kilogram of diet: manganese, 54; zinc, 34; iron, 15; copper, 2; iodine, .6. 2
containing 2,645,2,755, 2,865, and 2,976 kcal/ MEu/kg. The TMEn of experimental diets (2,702, 2,812, 2,928, and 3,010 kcal/kg) were determined by the method of Sibbald (1976), using adult roosters. Results are discussed in terms of calculated ME„ to facilitate comparisons with previous research. Diets were formulated using National Research Council (NRC, 1984) nutrient values for feed ingredients. Experimental diets were also analyzed for protein by the method described by the Association of Official Analytical Chemists (1984). Amino acids were formulated to provide daily intake requirements (Harms, 1983) based on projected feed consumption. The protein and amino acids were formulated
on a per therm basis for each of the four experimental energy diets. Hen performance was determined for four 28-day laying periods from 20 to 36-wk of age. Hens were housed in treatment temperatures at 18 wk of age for a 2-wk acclimation period. Egg production and mortality were recorded daily. Egg weights from a 1-day collection and feed intake were determined on a weekly basis; body weights were determined bi-weekly. Maintenance requirements were calculated by subtracting ME„ requirements for production from MEQ intake using gross energy values for egg mass and body tissue with .5 efficiency of utilization of MEn (Peguri, 1987).
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53.85 2.00 4.36 2.91 18.31 .099 .125 1.95 .065 .3 3.0 2.0 3.0 5.0 3.13 100.10
Ground yellow com Animal fat Sand Solka floe1 Soybean meal (46.5% CP) DL-methionine Vitamin mix Dicalcram phosphate Trace mineralsr Salt Corn gluten meal (62% CP) Alfalfa meal (17% CP) Wheat middlings Limestone, S-mm particle size Limestone, ground
128
PEGURI AND COON
TABLE 2. Effect of dietary MEn density and temperature on feed intake (g/day) of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C MEn (kcal/kg) 2,645 2,755 2,865 2,976
S*
16.1 111.9 113.6 109.0 106.0 110.1a
18.9 111.1 107.9 110.7 107.6 108.3a
22.2 105.0 103.0 104.4 99.2 102.9b
25.0 (g/day)3 99.0 101.7 101.5 95.6 101.0b
27.8 91.2 101.6 95.3 96.5 98.3C
31.1 91.2 91.1 87.5 83.8 88.4 d
X2
104.011 103.2ab 101.4b 98.1 c
The formula used was Maintenance requirement = MEn intake - (2.86 kcal X EGM) - (6 x BWCHD) mean body weight (kg) where the maintenance requirement was calculated as Jkilocalories of MEn per kilogram of hen body weight per day, EGM was mean egg mass in grams per day, and BWCHD represents grams of body weight change per hen per day. The 2.86 and 6.0 kcal constants for egg mass and body weight change, respectively, reflect the gross energy values and MEn efficiency of utilization for the production components. The least significant difference test (Steel and Torrie, 1960) was used at a 5% level of significance. The data were analyzed using the following model:
temperatures, body weights, egg mass production, and body weight changes used as independent variables. The criteria used to select the independent variables were R 2 adjusted for number of independent variables, t values of the coefficients of the independent variables, and the Cp Mallows' statistic. RESULTS AND DISCUSSION
Feed intake was significantly lower in treatments in which temperatures were higher (Table 2). Intake was decreased by 12 g/day between 16 and 27.8 C. The reduction in feed consumption (assuming an average ration with 2,810 kcal MEn/kg) equals about 1 g (2.8 kcal of MEn) per Celsius degree. Feed intake was decreased by about 10 g or 28.1 kcal between 31.1 and 27.8 C, implying a decrease in consumption of 8.51 kcal per Celsius degree. A change of intake of 8 g between 18 and 25 C indicates a thennoneutral zone does not exist or is smaller than generally accepted. This is r Y,ijrk = u + Ti + TRj + CTxTR^j + Zij also suggested by the data of Emmans (1974), + Wr + (W x TR)j, indicating a decrease in intake of 3.93 kcal + (W x T)k + e i ^ MEn/C between 15 and 29 C. Polin (1983) suggests a 26% decrease in feed intake where u, is the overall mean, T is temperature, between the thennoneutral zone (18 to 25 C) TR is dietary energy treatment, and W is and 31.1 C. In the present experiment, the weeks. The zy is the term for the whole-plot reduction in feed intake from 31.1 C to 18 and error, and ejj* is the term for split-plot error. 25 C was 22.5 and 16.4%, respectively. The Regression equations were performed when smaller reduction in feed intake from 18 C and appropriate. 25 C to 31.1 C compared with those reported A model to predict MEQ intake was in previous research may be explained by the obtained using multiple regression terms as high ventilation rate maintained at the hot outlined by Weisburg (1980) and the statistical temperature. McDonald (1978) suggested heat package of the SAS Institute (1982). The MEn loss is directly related to the square root of the intake was the dependent variable with various air velocity. The air velocity at 31.1 C was
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Means within columns or rows with no common superscripts differ significantly (P<05). The mean square error of the whole plot was 264.98 with 120 df. 2 Means of 576 observations. 'Means of 96 observations. 4 Means of 386 observations. lr
129
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE TABLE 3. Effect of time and temperature upon the feed intake of DeKalb White Leghorn layers from 20 to 36 wk of age 1 Temperature, C Week
16.1
18.9
225
1 2 3 4 5 6 7 8 9 10 11 12 13 14 IS 16 X*
785 94.0 875 102.7 115.0 119.4 113.6 123.8 113.5 120.7 111.1 113.0 118.5 119.8 115.3 1165 110.1a
86.2 91.1 88.8 106.7 107.8 114.9 109.7 118.3 113.7 114.6 1115 115.0 118.2 117.1 114.3 121.3 109.38
76.1 82.6 85.7 101.6 103.7 108.8 1073 105.9 109.7 108.8 109.4 108.7 109.3 110.8 1055 113.0 102.9b
25.0
27.8
31.1
X2
73.8 783 78.7 92.0 103.3 1015 101.9 101.0 105.4 103.1 105.8 102.5 104.0 1073 107.6 106.5 98.3C
66.5 653 81.6 79.7 893 88.0 905 93.3 93.6 94.7 92.6 94.4 94.7 96.6 99.8 93.6 88.4 d
76.1J 813* 84.8 h 97.4 h 103.58 105.3ef 1065* 107.4cd 107.3°* lOS.l** 104.6*1 104.7* I08.8 b 110.6a 108.1 bc U0.1 a
ftrMmrt'
""JMeans within columns or rows with no common superscripts differ significantly (P<.05). 'The mean square error of the whole plot was 264.98 with 120 df; the mean square error for the split plot was 29.80 with 2,025 df. Means of 144 observations. 3 Means of 36 observations. ''Means of 394 observations.
.198 m3/min per bird as suggested by DeKalb's Breeder Guide (Anonymous, 1985). The ventilation rate may have produced an increment in the amount of heat lost by the hens, which increased feed intake. The interaction of temperature and weeks (Table 3) was significant (P<.0001). The difference in consumption due to temperature between hens at 16.1 and 31.1 C was larger for the hens 16 wk into the experiment than during the 1st wk (22.6 versus 11.7 g). The interaction between dietary ME,, density and temperature was not significant (P>.25), but the interaction between dietary MEQ density and weeks into experiment (Table 4) was significant (P<.01). Differences in feed intake were small the 1st wk into the experiment and larger after that The regression obtained for predicting MEQ intake had an adjusted R2 of 99.65, a residual mean square of 16.97, and the number of observations used was 2,181. The prediction equation was MEn intake = (BW-75)(173.91 1.563 T) + 2.08 x EGM + 1.72 x BWCHD, where ME„ was in kilocalories per day, BW was in kilograms, T was the mean daily
temperature in C, EGM was in grams per day, and BWCHD was in grams per day. The standard errors for the coefficients were temperature = .0541, body weight (kg)-75 = 2.2719, egg mass (g/day) = .0501, and body weight change (g/day) = .1542. The high R2 value for the equation suggested the various independent variables produced a linear response in MEQ intake. The regression coefficients utilized for egg mass and body weight change for the hen production data were less than empirical values utilized for determining the maintenance requirement. Peguri and Coon (1988) reported temperatures from 7 to 37 C produced a quadratic response for feed intake, mean body weight, egg production, egg weight, and egg mass. The authors also showed a cubic response for the effect of temperature on mean body weight gain. The data reported herein contained effects of a smaller range of temperatures, thus producing a linear response. Feed intake was significantly decreased by the increase in energy density per kilogram of diet (Table 4). Dietary energy levels of 2,865
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76.1 79.5 86.8 101.6 101.7 993 114.0 102.3 108.1 106.4 1083 943 108.1 111.9 106.6 110.2 101.0b
130
PEGURI AND COON
TABLE 4. Effect of time and dietary ME„ density upon the feed intake of DeKalb White Leghorn layers from 20 to 36 wk of age * ME,,, kcal/kg Week
2,645
2,755
2,865
2,976
x2
76.8 76.2 80.5 93.9 100.0 1015 102.0 103.8 103.7 105.6 103.2 101.9 105.2 106.2 103.1 106.0 98.1C
76.1 k 81.5* 84.8* 97.4 h 10338 105.3ef 106^* IMA"* 107.3^ 108.1bc 104.6% 104.7* 108.8b 110.6" lOS.l1* 110.1"
3
77.2 87.0 87.9 100.4 105.1 107.9 108.4 108.4 108.9 108.8 108.5 106.8 111.6 113.3 111.6 112.8 104a
76.1 82.4 85.8 99.0 105.3 107.2 107.1 109.5 109.2 109.1 107.7 106.1 110.3 113.6 109.9 112.0 103.2"*
Means within columns or rows with no common superscripts differ significantly (P<.05). rhe mean square error of the whole plot was 264.98 with 120 df, and for the split plot 29.80 with 2,025 df. 2 Means of 144 observations. 3 Means of 36 observations, ^ e a n s of 394 observations. lr
and 2,976 kcal MEn/kg significantly decreased feed intake compared with intake of pullets fed the diet containing 2,645 kcal MEn/kg. Daily dietary energy intake decreased 28 kcal (Table 5) between 27.8 and 31.1 C. The 1.23 g reduction in egg mass production between 27.8 and 31.1 C did not account for the much lower MEn intake at 31.1 C, indicating a lower maintenance requirement. The MEn intake at 31.1 C was about the same for all diets except for the lower intake of hens fed diets containing 2,645 kcal MEJkg. Increments in energy densities from 2,645 up to 2,865 kcal MEJkg significantly increased MEn intake (Table 5) from 2,645 kcal/ kg. The increase in energy density from 2,865 and 2,976 kcal MEn/kg of diet failed to further significantly increase MEn intake. The MEn intake of layers at 31 C was very similar for all energy diets except for the hens fed 2,645 kcal MEn/kg diet. The present research indicates the failure of higher energy diets to increase energy intake for layers in hot temperatures for diets above 2,755 kcal MEJkg. Morris (1968) concluded MEn intake by White Leghorns increases by 2 or 3% for each 10% increase in
dietary energy. Marsden et al. (1973) found a 5% increment in energy intake when dietary energy was increased from 2,600 to 2,865 kcal ME„/kg. A subsequent increase to 3,100 kcal MEn/kg from 2,865 kcal MEn/kg did not increase MEn intake of birds housed at 21 C; however, the 3,100 kcal MEn/kg diet increased intake at 15 C by 3% (Marsden et al, 1973). hi the present study, MEn intake was affected to a larger extent between 2,645 and 2,865 kcal MEn/kg (Table 3), results similar to those found by Marsden et al. (1973). The increment of ME,,, intake due to increments in energy density of 100 kcal MEn/kg diet follows the law of diminishing returns. The response to the increments in energy was curvilinear, MEj, = -1,112.3 + (.9454 x ED) - (.0001591 x ED2) where ED represents MEn for diets (kilocalories per kilogram). The MEn intake increased 3.30% between 2,645 and 2,755 kcal; 2.18% between 2,755 and 2,865 kcal MEn/kg; and only .48% between 2,865 and 2,976 kcal MEn/kg. The 6.51% increment in MEn intake for layers fed diets between 2,645 and 2,976 kcal was higher at moderate temperatures (16.1 to
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 3?*
131
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 5. Effect of dietary ME„ density and temperature on ME„ intake of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976 i*
16.1 295.9 311.3 312.2 315.5 309.2"
18.9 292.9 297.2 317.3 320.1 307.1"
22.2 277.8 283.9 299.1 295.3 289.0 b
25.0 (kcal/day)3 278.1 280.3 290.8 284.5 283.4 b
27.8
31.1
5?
264.2 279.8 272.9 287.1 276.0°
241.2 250.9 250.8 249.3 248.^
275.2C 284.3 b 290.5" 291.9*
27.8 C) compared with 3.35% at 31.1 C (Table 5). The increment response of 5.8% MEn intake was only marginally lower for layers housed at 16.1 to 27.8 C and fed diets between 2,645 and 2,865 kcal MEn/kg. Layers housed at 31.1 C and fed diets between 2,645 and 2,865 kcal MEn/kg showed approximately the same percentage increment of MEQ intake (3.98% increment versus 3.35) as layers fed the complete range of energy density diets. The data suggests MEn intake at 31.1 C cannot be increased significantly for layers fed energy density levels above 2,865 kcal MEn/kg. The research indicated that between temperatures from 16.1 to 27.8 C, a 1% increment in MEn density per kilogram with diets from 2,645 to 2,865 kcal MEn/kg resulted in a .7% increment of MEn consumption or .054 kcal for each kilocalorie added to the diet The interaction between dietary MEn density and temperature was not significant (P>.12). The interaction of temperature by weeks was significant (P<.001) because the difference in MEQ intake between the lowest and highest temperature was 32 kcal the 1st wk and 63 kcal the last week, indicating that the animals modified MEn intake to compensate for differences in temperature (Table 6). The interaction between weeks and energy density was also significant (P<.001) (Table 7). Differences in MEn intake due to energy density were large during the 1st wk, but they decreased with the adaptation of the birds to the diet The significant differences in egg production (Table 8) were due, at least in part, to chance; there was a lack of consistent trends
mat indicated specific effects of warm or cold temperatures. The results of the experiment reported herein confirm the report of Emmans (1974) that the rate of lay in White Leghorns fed equal quantities of nutrients is independent of temperature between 5 to 30 C. Percentage hen-day egg production in the present research was not related (P<.05) to energy density in the diet, in contrast with the finding of Marsden et al. (1987), indicating that egg output is significantly increased by higher energy densities. Interactions for MEn by temperature and MEn by week were not significant, but the interaction of temperature and time was highly significant (P<.01) (Table 9). The temperatures that reduced egg production showed a larger difference on performance during the first 3 wk, and then the egg production became similar later in the 16-wk trial. Egg weight was significantly decreased by higher temperatures (Table 10). Hens housed in cooler temperatures produced heavier eggs. Egg weight decreased significantly at 27.8 C (P<.05). Increasing temperature to 31.1 C significantly decreased egg weight by 1.82 g compared with eggs at 27.8 C. The largest decrease in egg weights was between 27.8 and 31.1 C. Emmans (1974) reported egg weights are depressed at temperatures above 25 C, which is in good agreement with the present research. The interaction of time and temperature (Table 11) was significant (P<.0001). The differences in egg weight were small in Week 1 between 16.1 and 31.1 C (39.1 g versus 39.7 g); however, the difference increased after the
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""^Means within columns or rows with no common superscripts differ significantly (P<05). ^ e mean square error of the whole plot was 2,086.8 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations.
132
PEGURI AND COON TABLE 6. Effect of time and temperature upon the MEn consumption of DeKalb White Leghorn layers from 20 to 36 wk of age * Temperature, C
Week
18.9
16.1
22.2
25.0
27.8
31.1
3? 214 n 229™ 2381 2731 291 h 296* 298 rf 302 cd 301 cde 304 bc 299 def 294* 306 b 310* 304 bc 309*
3
— (kcal/day)
219 264 245 288 323 335 319 347 319 339 312 318 333 336 324 326
242 256 249 300 303 323 308 332 320 322 312 323 332 329 321 341
214 232 240 284 291 305 302 298 308 306 307 305 307 311 295 317
214 223 244 285 286 279 320 287 303 299 305 265 303 314 299 309
207 220 221 258 290 284 286 284 296 290 297 288 292 302 302 299
187 183 229 224 251 247 253 262 263 266 260 265 266 271 280 263
309"
307 a
289 b
283 b
276 c
248 d
"""Means within columns or rows with no common superscripts differ significantly. *The mean square error of the whole plot was 2,086.8 wim 120 df; for the split plot, the mean square error was 2,316.14 with 2,025 df. 2 Means of 144 observations. 3 Means of 24 observations. 4 Means of 394 observations.
TABLE 7. Effect of time and dietary ME„ density upon the ME„ consumption of DeKalb White Leghorn layers from 20 to 36 wk of age i ME,,, kcal/kg Week
2,645
2,755
2,865
2,976
3? 214 n 229m 2381 2731 291 h 296f« 298®f 302 cd 301 cde 304 bc 299*1 294811 306 b 310* 304*° 309*
3
(kcal/day)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 5E4
204 230 232 265 278 285 287 287 288 287 287 282 295 299 295 298
209 227 236 272 290 295 295 301 301 300 297 292 303 312 303 309
214 234 243 275 296 299 307 310 308 311 305 298 310 313 309 314
228 227 240 279 298 302 304 309 309 314 307 303 313 316 307 309
275 c
284 b
290*
283 b
""""Means within columns or rows with no common superscripts differ significantly (P<05). ^ h e mean square error of the whole plot was 2,086.8 with 120 df and for the split plot 236.14 with 2,025 df. 2 Means of 144 observations. 3 Means of 36 observations. 4 Means of 394 observations.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 3E*
133
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 8. Effect of dietary ME„ density and temperature on hen-day egg production of DeKalb White Leghor, layers from 20 to 36 wk of age * Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976 5*
16.1
18.9
22.2
25.0
27.8
31.1
3?
81.59 83.27 81.46 83.85 82.52 bc
82.40 83.71 86.43 81.68 83.05 abc
82.56a 83.15" 83.36* 82.66a
- (%)3 83.01 81.39 83.04 80.13 si^1*
84.06 85.71 84.78 84.74 84.82a
80.67 81.46 83.09 81.02 81.56°
83.61 83.33 83.38 84.51 83.71 ab
a_c
2,645 and 2,865 kcal MEJkg diets. No significant difference was observed in egg weights between hens fed 2,755 and 2,976 kcal MEn/kg diet. Egg weight was not increased by increased dietary MEQ density for hens housed at or above 27.8 C. The interactions of ME„
3rd wk of the experiment, and at 16 wk, it was 3.5 g (58.5 g versus 55.0 g). An increase in energy density significantly increased egg weight (Table 10) in agreement with results of Marsden et al. (1987). Average egg weight differed by .8 g between hens fed
TABLE 9. Effect of time and temperature upon the hen day egg production of DeKalb White Leghorn layers from 20 to 36 wk of age1 Temperature, C Week
16.1
18.9
22.2
27.8
31.1
3?
11.4 37.7 64.5 86.6 89.9 94.0 93.6 94.2 92.7 92.4 92.2 86.1 90.8 93.3 92.9 92.8
10.4 38.2 62.5 87.4 935 94.8 94.6 94.8 93.8 92.9 93.5 92.8 92.8 93.1 93.1 92.7
U.4 h 37.98 67.9* 87.0° 92.1 d 94.4 ab 94.3 ab 94.7a 94.1 abc 93.9 abc 93.9 abc 92.2 d 92.9°* 93.4 abcd 93.5"*° 93.2 bcd
81.6°
82.5 bc
13.2 36.7 67.4 91.8 93.0 93.2 92.8 94.0 94.2 93.5 94.1 93.5 92.4 93.0 93.5 92.7 KiXf**
25.0 (fnl 3
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
J* a-fai
8.7 32.7 675 83.5 90.8 94.2 93.2 93.3 93.9 94.4 94.0 92.9 93.4 92.3 93.1 92.9
13.6 40.5 71.9 87.7 93.4 94.9 95.9 96.4 96.4 95.0 95.4 94.9 95.3 95.3 95.7 95.0
si^
84.8"
11.1 41.9 73.6 85.1 92.5 95.3 95.4 95.5 93.9 95.2 94.4 92.9 93.0 93.4 92.9 93.4 g37ab
'Means within columns or rows with no common superscripts differ significantly (P<05). 'The mean square error of the whole plot was 114.72 with 120 df and for the split plot 32.72 with 2,025 df. •'Means of 144 observations. 3 Means of 36 observations. Means of 394 observations.
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Means within columns or rows with no common superscripts differ significantly (P<.05). 'The mean square error of the whole plot was 192.64 with 120 df. Means of 576 observations. 3 Means of 96 observations. Means of 386 observations.
134
PEGURI AND COON
TABLE 10. Effect of dietary ME„ density and temperature on average egg weight of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C ME,,
16.1
(kcal/kg) 2,645 2,755 2,865 2,976 5*
52.36 53.63 53.15 54.49 53.41 a
18.9 52.81 52.73 54.35 53.33 53.31*
22.2
25.0
51.62 52.11 53.52 52.36 52.40 bc
M3 uw52.93 52.40 53.21 53.51 52.02^
27.8
31.1
5?
51.37 52.71 51.73 52.36 52.05°
50.39 50.29 50.19 50.06 50.23 d
51.91 b 52.31 ab 52.69" 52.69°
a-di
Means within columns or rows with no common superscripts differ significantly (P<05). rhe mean square error of the whole plot was 23.326 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations. lr
the present experiment. Amino acid intake for hens at each temperature was that recommended by Harms (1983) or higher, suggesting differences in egg weight are not due to amino acid levels but to the level of energy intake, particularly above 25 C. The diets were
TABLE 11. Effect of time and temperature upon the egg weight of DeKalb White Leghorn layers from 20 to 36 wk of age * Temperature, C Week
16.1
18.9
22.2
25.0
27.8
31.1
3?
40.5 45.6 47.0 49.5 51.1 52.0 52.9 53.2 54.0 53.9 54.7 54.9 55.3 55.8 56.0 56.4
39.7 43.3 46.6 47.3 49.7 49.9 50.7 51.1 51.5 51.9 52.5 52.8 53.4 53.9 54.6 55.0 50.2 d
39.91 44.9 k 47.7J 49.51 52.7 h 53.5« 53.7f 54.3 f 54.7* 55.1 e 55.2 d 55.7 d 55.2C 56.3 b 56.7"* 56.9"
(r& V&)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 i*
39.1 44.4 48.3 49.7 52.4 53.4 55.2 55.1 55.8 56.2 56.4 56.7 57.2 57.7 58.4 58.5 53.4 a
40.4 46.1 48.6 49.8 52.7 53.5 54.4 54.9 55.4 55.5 56.1 56.7 56.3 57.1 57.3 58.1 53.3 a
38.2 44.8 47.8 50.5 51.1 52.8 53.9 54.0 54.8 54.8 55.1 55.6 55.8 55.9 56.7 56.7 53.0 ab
41.4 45.3 48.0 50.5 52.6 545 54.1 54.2 54.6 55.8 55.7 54.9 56.0 57.5 57.1 56.5 52.4 be
52.0°
"Means within columns or rows with no common superscripts differ significantly (P<05). lr The mean square error of the whole plot was 23.32 with 120 df and for the split plot 3.168 with 2,303 df. 2 Means of 144 observations. 3 Means of 36 observations. 4 Means of 394 observations.
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density and temperature (P>.12) and MEQ density and week (P>.22) were not significant. Payne (1967) indicated that at 30 C, birds fed very high energy diets overcame the egg weight depression that occurred in hens fed lower energy diets. That was not the case in
135
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 12. Effect of dietary MEn density and temperature on mean body weight of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C M^ (kcal/kg) 2,645 2,755 2,865 2,976
*
16.1 1.537 1.601 1.603 1.620 1.590*
18.9 1.537 1.510 1.618 1.614 1.569b
22.2 1.509 1.508 1.544 1.556 1.532c
25.0 (kg)3 1.490 1502 1530 1.538 1.515d
27.8
31.1
5?
1.440 1.515 1.462 1510 1.483*
1.348 1.399 1.408 1.405 1.390*
1.478d 1.506° 1.529b 1.540"
formulated to provide adequate levels of calcium, protein, and amino acids for expected low intakes for hens housed in hot temperatures. The protein and amino acids also had to be adjusted on a therm basis to provide hens equivalent daily intakes of protein and amino acids with various energy density levels in experimental feeds. Mean body weights decreased linearly between 16.1 and 27.8 and abruptly decreased at 31.1 C (Table 12), indicating the difficulty the birds housed at 31.1 C had to increase thenbody weight when compared with birds at cooler temperatures. The body weight change followed the same trends (Table 13); average body weight and gain were the lowest at 31.1 C. Energy density had a significant effect on both mean body weight and daily body weight gain. The higher the energy content of the ration, the heavier the birds and the higher the body weight gain. The MEn by temperature interaction was not significant for weight or gain. The temperature by week interaction was significant for mean weight (P<.001) and for weight gain (P<01). The hens housed in hotter temperatures during the 2-wk acclimation period were slightly lighter at 20 wk of age than hens housed in cooler temperatures. The layers' mean weight and gain, however, were further apart at 36 wk of age because of the large difference in MEn consumption for the 16-wk period (Table 3). Higher dietary MEn density diets improved feed conversion significantly (Table 14). The higher the MEn level in the diet, the better the feed conversion. Feed conversion improved an
average of .0273 g feed/g egg mass for each degree of increase in temperature. Dietary MEn density improved feed conversion .05 g feed per gram of egg mass for each 100 additional kilocalories of MEn per kilogram of diet. Feed conversion was significantly improved between 27.8 and 31.1 C. Feed conversion was optimal at 31.1 C for hens fed the highest levels of dietary MEn m m e diet. However, egg weights were depressed by about 2 g at 31.1 C compared with those of hens at 27.8 C. The most adequate practice to maximize egg size and feed conversion for young hens may be to keep hens at 27.8 C or below until an adequate egg size is obtained and then increase the house temperature to 31.1 C. The interaction of MEQ and temperature was not significant Maintenance energy requirement decreased 2.21 kcal MEn/kg of body weight per Celsius degree increase in temperature between 18.9 and 22.2 C (Table 15). The rate of decrease was .10 kcal MEn/kg of body weight per Celsius degree between 22.2 and 25.0 C. The change in maintenance requirement was .55 kcal MEn/kg of body weight per Celsius degree between 25 and 27.8 C. Maintenance requirement decreased 2.84 kcal MEn/kg of body weight per Celsius degree between 27.8 and 31.1 C. The present research indicated the maintenance requirement for energy was higher at cold temperatures, reached a plateau between 22.2 and 27.8 C, and decreased sharply at 31.1 C. Coon and Peguri (1985) suggested the maintenance requirement for hens was approximately 60% of the MEn
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"Means within columns or rows with different superscripts differ significantly (P<05). 'The mean square error of the whole plot was .04592 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations.
136
PEGURI AND COON
TABLE 13. Effect of dietary MEn density and temperature on mean body weight gain of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C ME„ (kcal/kg) 2,645 2,755 2,865 2,976
i4
16.1
18.9
22.2
2.72 3.17 2.97 3.29 3.04a
2.41 2.62 3.12 2.90 2.76b
2.86 2.71 2.72 2.87 2.79 ab
25.0
27.8
31.1
5?
2.14 2.33 2.46 2.50 2.36°
1.88 1.79 1.91 2.17 1.94d
2.34 b 2.51 ab 2.61* 2.73 a
f irMmrr'
2.30 2.41 2.48 2.64 2.46c
a_d
TABLE 14. Effect of dietary ME„ density and temperature on feed conversion of DeKalb White Leghorn layers between 20 to 36 wk of age 1 Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976
#
16.1
18.9
22.2
25.0
27.8
31.1
i2
2.57 2.60 2.47 2.42 2.52 a
2.50 2.39 2.40 2.38 2.41 b
2.43 2.37 2.34 2.24 2.34°
2.46 2.38 2.29 2.20 2.33 c
2.38 2.31 2.26 2.19 2.28 d
2.19 2.16 2.06 2.04 2.1 l e
2.42 a 2.37b 2.3 l c 2.25d
"Means within columns or rows with no common superscripts differ significantly (P<05). 1 The mean square error of the whole plot was .1093, with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations.
TABLE 15. Effect of dietary ME„ density and temperature on maintenance ME requirement of DeKalb White Leghorn layers from 20 to 36 wk of age 1 Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976
**
16.1
18.9
22.2
25.0
27.8
31.1
5?
99.38 103.40 102.50 102.90 102.00"
97.38 98.86 101.20 105.80 100.80*
88.71 92.87 97.30 95.15 93.78b
92.82 93.67 95.98 92.65 93.5 l b
89.45 90.98 91.89 95.59 91.98 b
80.69 84.32 82.26 83.10 82.59°
91.41 b 94.01* 95.20* 95.87*
'"Means within columns or rows with different superscripts are significantly different (P<05). 'The mean square error of the whole plot was 413.48, with 120 df. 2 Means of 576 observations. Means of 96 observations. Means of 386 observations.
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Means within columns or rows with no common superscripts differ significantly (P<05). The mean square error of the whole plot was 3.68 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. ''Means of 386 observations. 1
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
REFERENCES Anonymous, 1985. DeKalb's Breeder Guide. DeKalb Poultry Research, Inc., DeKalb, IL. Association of Official Analytical Chemists, 1984. Official Methods of Analysis. 14th ed. Association of Official Analytical Chemists, Washington, DC. Coon, C. N., and A. Peguri, 1985. Predicting feed intake for layers. Pages 103-112 in: Proceedings of the 46th Minnesota Nutrition Conference, St Paul, MN.
Davis, R. H., D.E.M. Hassan, and A. H. Sykes, 1972. The adaptation of energy utilization in the laying hen in relation to ambient temperature. J Agric. Sci. 79: 363-369. Davis, R. H., DJB.M. Hassan, and A. H. Sykes, 1973. Energy utilization in the laying hen in relation to ambient temperature. J. Agric. Set Camb. 21: 173-177. Etrurians, G. C , 1974. The effects of temperature on the performance of laying hens. Pages 79-90 in: Energy Requirements of Poultry. T. R. Morris and B. M. Freeman, ed. British Poultry Science Ltd., Edinburgh, Scotland, UJC. De Groote, G., 1974. Utilization of metabolizable energy. Pages 113-133 in: Energy Requirements of Poultry. T. R. Morris and B. M. Freeman, ed. British Poultry Science Ltd., Edinburgh, Scotland, UJC. Harms, R. H., 1983. Commercial layer management should be adjusted for strain and season. Feedstuff's 55(40):65. Huyghebaert, G., G. DeMunter, and G. De Groote, 1989. Energy expenditure of laying hens under different lighting patterns. Pages 255-258 in: Energy Metabolism of Farm Animals. Y. van der Honing and W. H. Close, ed. Proceedings of 11th Symposium, Lutheran, Netherlands. PUDOC, Wageningen, Netherlands. Marsden, A., T. R. Morris, and A. S. Cromarty, 1987. Effects of constant environmental temperatures on the performance of laying pullets. Br. Poult Sci. 28: 361-380. Marsden, A., E. Wetbli, N. Kinread, and T. R, Morris, 1973. The effect of environmental temperatures on feed intake of laying hens. World's Poult. Sci. J. 29: 286-287. McDonald, M. W., 1978. Feed intake of laying hens. World's Poult. Sci. J. 34:209-221. Morris, T. R., 1968. The effect of dietary energy level on the voluntary caloric intake of laying hens. Br. Poult. Sci. 9:285-295. National Research Council, 1984. Nutrient Requirements of Poultry. 8th ed. National Academy of Sciences, Washington, DC. Payne, C. G., 1964. The influence of environmental temperature on poultry performance. Pages 117-120 in: 2nd European Poultry Conference, Bologna, Italy. Payne, C. G., 1966a. Practical aspects of environmental temperature for laying hens. World's Poult Sci. J. 22:126-139. Payne, C. G.. 1966b. Developments in the use of artificial heating for the control of the animal environment Report of the Rural Electrification Conference, 1966. Electricity Council, London, England. Payne, C. G., 1967. Environmental temperature and egg production. Pages 235-241 in: The Physiology of the Domestic Fowl. C. Horton-Smith and E. C. Amoroso, ed. Oliver and Boyd, Edinburgh, Scotland, UJK. Peguri, A., 1987. Energy requirements of the laying hen. PhX>. Dissertation, University of Minnesota, St Paul, MN. Peguri, A., and C. Coon, 1988. Development and evaluation of prediction equations for metabolizable and true metabolizable energy intake for the DeKalb XL-Link White Leghorn hen. Pages 199-211 in: Proceedings of the 49th Minnesota Nutrition Conference, St Paul, MN. Peguri, A., and C. N. Coon, 1989. The efficiency of
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consumed based on a multiple regression of production data at various environmental temperatures. The MEQ requirements for maintenance determined in the present study were approximately 50% of ME,, consumed, because the MEu required for egg mass and body weight were based on higher ME„ empirical values (Peguri and Coon, 1989). De Groote (1974) reviewed eight reports and stated that maintenance requirements varied between 99 and 133 kcal/BW-75 per day, depending upon age and environmental temperature. Maintenance requirements in the research reported herein ranged from 82.6 to 102 kcal MEn/kg body weight for young hens housed in temperatures ranging from 16.1 to 31.1 C. De Groote (1974) also reported 64 to 86% efficiency of utilization for MEn for egg production. Huyghebaert et al. (1989) reported a large range of MEQ efficiency for utilization of .5 to .8, depending on genetic, environmental conditions, and methods of calculations. The MEQ efficiency of utilization of .5 for production utilized to determine maintenance requirements is within the lower portion of the reported range of ME„ efficiencies. Peguri and Coon (1989) reported the mean MEQ efficiency of utilization for maintenance was .61 for temperatures 7.2 C to 35 C. Reid et al. (1978) stated the efficiency of utilization of MEn was 62% for maintenance and 63% for production. The researchers utilized 5 kcal/g for body weight change and 1.6 kcal/g egg mass instead of 3 kcal/g for body weight gain and 1.42 kcal/g egg mass reported by Peguri (1987). Maintenance requirement for energy appeared to increase with dietary energy density (Table 15). A possible explanation is that the efficiency of utilization of feed energy for egg production and body weight gain may decrease as energy density increases in the diet, or alternatively the amount of energy required per unit of body weight gain may increase as the energy concentration per kilogram of diet is increased.
137
138
PEGURI AND COON onmental temperature and rationing treatments on the productivity of pullets fed on diets of differing energy content. Rhod. J. Agric. Res. 10:3-21. Smith, A. J., and J. Oliver, 1972b. Some nutritional problems associated with egg production at high environmental temperatures. 4. The effect of prolonged exposure to high environmental temperatures on the productivity of pullets fed on high energy diets. Rhod. J. Agric. Res. 10:43-60. Steel, R.G.D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, New York, NY. Weisberg, S., 1980. Applied linear regression. John Wiley and Sons, New York, NY. Wilson, W. O., T. Siope, P. Ingkasuwan, and F. B. Mather, 1972. The interaction of temperature of 21 C and photoperiod of 8 and 14 hours on White Leghorn hens' production. Arch. Geflugelkd. 37:41-45.
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utilization of dietary energy for layers and the law of diminishing returns. Pages 270-299 in: Proceedings of the 50th Minnesota Nutrition Conference, St. Paul, MN. Polin, D., 1983. The influence of environmental temperature on the feed intake of laying hens examined. Feedstuffs 55(5):21-22. Reid, B. L., ML E. Valencia, and P. M. Maiorina, 1978. Energy utilization by laying hens. 1. Energetic efficiencies of maintenance and production. Poultry Sci. 57:461-465. SAS Institute, 1982. SAS® User's Guide: Statistics. SAS Institute Inc., Cary, NC. Sibbald, I. R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poultry Sci. 55:303-308. Smith, A. J., and J. Oliver, 1972a Some nutritional problems associated with egg production at high environmental temperatures. 1. The effect of envir-
1991 Poultry Science 70:126-138 INTRODUCTION
Payne (1964; 1966a,b; 1967) demonstrated that feed intake decreases as environmental temperatures increase. Experiments conducted to evaluate the effect of temperature on ME intake have shown that hens have the ability to adjust feed intake to supply ME needed for maintenance and production (Davis et al., 1972, 1973; Smith and Oliver, 1972a,b; Wilson et al., 1972). Morris (1968) indicated that groups of pullets offered different diets tend to adjust consumption so as to maintain the same caloric intake, although the adjustment by pullets was imperfect in most cases, as birds fed high energy diets overconsumed calories. Marsden et al. (1987) found dietary energy content had small but significant effects on egg weight and egg output in experiments in which temperature was controlled by adjusting the ventilation rate. The factors that determine energy intake need to be understood to predict energy intake with precision. The present experiment was designed to study the simultaneous effect of temperature and energy density levels on consumption of ME and
'Published as Paper Number 17,603 of the Scientific Journal Series of the Minnesota Agricultural Experiment Station. ^To whom correspondence should be addressed.
performance of laying hens at ventilation rates indicated to be optimum at each temperature in the breeders' management guide. MATERIALS AND METHODS
Fourteen hundred and forty DeKalb-XL layer hens were housed in six environmental rooms; each room contained 240 hens. The hens were randomly allotted, 2 hens per cage, with each experimental unit consisting of five cages. Six environmental temperatures were set at 16.1, 18.9, 22.2, 25.0, 27.8, and 31.1 C. The temperatures were kept constant for each room; however, changing outside ambient temperatures during the experiment produced small fluctuations of temperatures in the rooms. Temperatures were recorded daily in the morning and in the afternoon. The overall mean temperatures and standard deviations for the six rooms were 16.0 ± 1.4,19.0 ± .42, 22 ± .53, 24.6 ± .26, 27.7 ± .24, and 30.5 ± .49 C. Relative humidity was held between 50 and 60%. Ventilation rate was 47.1 L/min per bird at 16.1 C and was increased 10 L/min per bird for each degree increase in temperature. Sixty layers (six environmental units) at each temperature were fed for ad libitum consumption of corn-soybean diets (Table 1)
126
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ABSTRACT DeKalbXL White Leghorn hens 20 wk of age housed at 16.1,18.9,22.2,25.0,27.8, and 31.1 C were fed diets containing 2,645,2,755,2,865, and 2,976 kcal MEn/kg. Feed intake was 5.9 g lower (P<.05) when dietary energy was increased from 2,645 to 2,976 kcal MEg/kg and was 21.7 g lower when temperatures were increased from 16.1 to 31.1 C. The MEQ intake of hens at temperatures ranging from 16.1 to 31.1 C was 61.2 (P<05) kcal/hen per day lower in treatments with the higher temperatures. The MEQ intake of hens was also 16.7 kcal/day higher (P<.05) when energy density in the diet was raised from 2,645 to 2,976 kcal MEg/kg. Egg production was not affected by either temperature or dietary energy density. Egg weight increased .78 g (P<05) with increases in dietary energy density from 2,645 to 2,976 kcal ME^/kg and decreased 3.18 g (P<05) when temperatures were raised from 16.1 to 31.1 C. Mean body weights and body weight gains were significantly (P<05) higher in treatments with higher energy density and lower in treatments with higher environmental temperatures. Feed conversion was increased .41 g feed/g egg mass (P<05) at higher temperatures (16.1 and 31.1 Q and increased .17 g feed/g egg mass at higher energy densities (2,645 and 2,976 kcal MEj,/kg). Maintenance requirements were estimated at all temperatures. (Key words: temperature, laying hens, metabolizable energy, egg production, feed intake)
127
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 1. Percentage and calculated composition of Sets with four levels of energy fed to White Leghorn hens between 20 and 36 wk of age Ingredient and analysis
2,645 kcal/kg
2,755 kcal/kg
2,865 kcal/kg
2,976 kcal/kg
59.335 2.00
58.684 3.78
56.447 2.00 2.04 1.36 19.13 .104 .125 2.03 .065 .3 3.0 2.0 3.0 5.0 3.47 100.07
20.15 .111 .125 2.11 .065 .3 3.0 1.08 3.0 5.0 3.84 100.11
Calculated analysis MEQ, kcal/kg 2,645 Protein, % 16.37 Methionine, % .378 TSAA, % .663 Lysine, % .774 Calcium, % 3.59 Nonphytate phosphorus, % .453 Methionine, mg/therm 142.9 TSAA, mg/therm 250.67 Lysine, mg/therm 292.6 Calcium, g/therm 1.36 Nonphytate phosphorus, mg/therm 171.3 Analyzed TMBQ, kcal/kg 2,702 Analyzed CP, % 16.22
2,755 17.00 .394 .689 .807 3.74 .474 143.0 250.1 292.9 1.36 172.0 2,812 16.74
2,865 17.59 .412 .716 .839 3.89 .491 143.8 249.9 292.8 1.36 171.3 2,928 17.42
.• *
22.60 .126 .125 254 .065 .3 3.0
5.0 4.12 100.12 2,976 18.06 .434 .744 .887 4.04 .510 145.8 250.0 298.0 1.36 171.3 3,010 1851
^onnutritive filler (cellulose), Brown Co., Berlin, NH. The vitamin mix provided the following per kilogram of diet: vitamin A, 8550IU; vitamin D3,4,125 IU; vitamin E, 4 IU; menadione sodium bisulfite complex, 1.03 mg; riboflavin, 5.5 mg; niacin, 20.6 mg; pantothenic acid, 7.6 mg; folic acid, .275 mg; vitamin Bi 2 , 6.9 \lg. 3 The mineral mix provided the following in milligrams per kilogram of diet: manganese, 54; zinc, 34; iron, 15; copper, 2; iodine, .6. 2
containing 2,645,2,755, 2,865, and 2,976 kcal/ MEu/kg. The TMEn of experimental diets (2,702, 2,812, 2,928, and 3,010 kcal/kg) were determined by the method of Sibbald (1976), using adult roosters. Results are discussed in terms of calculated ME„ to facilitate comparisons with previous research. Diets were formulated using National Research Council (NRC, 1984) nutrient values for feed ingredients. Experimental diets were also analyzed for protein by the method described by the Association of Official Analytical Chemists (1984). Amino acids were formulated to provide daily intake requirements (Harms, 1983) based on projected feed consumption. The protein and amino acids were formulated
on a per therm basis for each of the four experimental energy diets. Hen performance was determined for four 28-day laying periods from 20 to 36-wk of age. Hens were housed in treatment temperatures at 18 wk of age for a 2-wk acclimation period. Egg production and mortality were recorded daily. Egg weights from a 1-day collection and feed intake were determined on a weekly basis; body weights were determined bi-weekly. Maintenance requirements were calculated by subtracting ME„ requirements for production from MEQ intake using gross energy values for egg mass and body tissue with .5 efficiency of utilization of MEn (Peguri, 1987).
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53.85 2.00 4.36 2.91 18.31 .099 .125 1.95 .065 .3 3.0 2.0 3.0 5.0 3.13 100.10
Ground yellow com Animal fat Sand Solka floe1 Soybean meal (46.5% CP) DL-methionine Vitamin mix Dicalcram phosphate Trace mineralsr Salt Corn gluten meal (62% CP) Alfalfa meal (17% CP) Wheat middlings Limestone, S-mm particle size Limestone, ground
128
PEGURI AND COON
TABLE 2. Effect of dietary MEn density and temperature on feed intake (g/day) of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C MEn (kcal/kg) 2,645 2,755 2,865 2,976
S*
16.1 111.9 113.6 109.0 106.0 110.1a
18.9 111.1 107.9 110.7 107.6 108.3a
22.2 105.0 103.0 104.4 99.2 102.9b
25.0 (g/day)3 99.0 101.7 101.5 95.6 101.0b
27.8 91.2 101.6 95.3 96.5 98.3C
31.1 91.2 91.1 87.5 83.8 88.4 d
X2
104.011 103.2ab 101.4b 98.1 c
The formula used was Maintenance requirement = MEn intake - (2.86 kcal X EGM) - (6 x BWCHD) mean body weight (kg) where the maintenance requirement was calculated as Jkilocalories of MEn per kilogram of hen body weight per day, EGM was mean egg mass in grams per day, and BWCHD represents grams of body weight change per hen per day. The 2.86 and 6.0 kcal constants for egg mass and body weight change, respectively, reflect the gross energy values and MEn efficiency of utilization for the production components. The least significant difference test (Steel and Torrie, 1960) was used at a 5% level of significance. The data were analyzed using the following model:
temperatures, body weights, egg mass production, and body weight changes used as independent variables. The criteria used to select the independent variables were R 2 adjusted for number of independent variables, t values of the coefficients of the independent variables, and the Cp Mallows' statistic. RESULTS AND DISCUSSION
Feed intake was significantly lower in treatments in which temperatures were higher (Table 2). Intake was decreased by 12 g/day between 16 and 27.8 C. The reduction in feed consumption (assuming an average ration with 2,810 kcal MEn/kg) equals about 1 g (2.8 kcal of MEn) per Celsius degree. Feed intake was decreased by about 10 g or 28.1 kcal between 31.1 and 27.8 C, implying a decrease in consumption of 8.51 kcal per Celsius degree. A change of intake of 8 g between 18 and 25 C indicates a thennoneutral zone does not exist or is smaller than generally accepted. This is r Y,ijrk = u + Ti + TRj + CTxTR^j + Zij also suggested by the data of Emmans (1974), + Wr + (W x TR)j, indicating a decrease in intake of 3.93 kcal + (W x T)k + e i ^ MEn/C between 15 and 29 C. Polin (1983) suggests a 26% decrease in feed intake where u, is the overall mean, T is temperature, between the thennoneutral zone (18 to 25 C) TR is dietary energy treatment, and W is and 31.1 C. In the present experiment, the weeks. The zy is the term for the whole-plot reduction in feed intake from 31.1 C to 18 and error, and ejj* is the term for split-plot error. 25 C was 22.5 and 16.4%, respectively. The Regression equations were performed when smaller reduction in feed intake from 18 C and appropriate. 25 C to 31.1 C compared with those reported A model to predict MEQ intake was in previous research may be explained by the obtained using multiple regression terms as high ventilation rate maintained at the hot outlined by Weisburg (1980) and the statistical temperature. McDonald (1978) suggested heat package of the SAS Institute (1982). The MEn loss is directly related to the square root of the intake was the dependent variable with various air velocity. The air velocity at 31.1 C was
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Means within columns or rows with no common superscripts differ significantly (P<05). The mean square error of the whole plot was 264.98 with 120 df. 2 Means of 576 observations. 'Means of 96 observations. 4 Means of 386 observations. lr
129
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE TABLE 3. Effect of time and temperature upon the feed intake of DeKalb White Leghorn layers from 20 to 36 wk of age 1 Temperature, C Week
16.1
18.9
225
1 2 3 4 5 6 7 8 9 10 11 12 13 14 IS 16 X*
785 94.0 875 102.7 115.0 119.4 113.6 123.8 113.5 120.7 111.1 113.0 118.5 119.8 115.3 1165 110.1a
86.2 91.1 88.8 106.7 107.8 114.9 109.7 118.3 113.7 114.6 1115 115.0 118.2 117.1 114.3 121.3 109.38
76.1 82.6 85.7 101.6 103.7 108.8 1073 105.9 109.7 108.8 109.4 108.7 109.3 110.8 1055 113.0 102.9b
25.0
27.8
31.1
X2
73.8 783 78.7 92.0 103.3 1015 101.9 101.0 105.4 103.1 105.8 102.5 104.0 1073 107.6 106.5 98.3C
66.5 653 81.6 79.7 893 88.0 905 93.3 93.6 94.7 92.6 94.4 94.7 96.6 99.8 93.6 88.4 d
76.1J 813* 84.8 h 97.4 h 103.58 105.3ef 1065* 107.4cd 107.3°* lOS.l** 104.6*1 104.7* I08.8 b 110.6a 108.1 bc U0.1 a
ftrMmrt'
""JMeans within columns or rows with no common superscripts differ significantly (P<.05). 'The mean square error of the whole plot was 264.98 with 120 df; the mean square error for the split plot was 29.80 with 2,025 df. Means of 144 observations. 3 Means of 36 observations. ''Means of 394 observations.
.198 m3/min per bird as suggested by DeKalb's Breeder Guide (Anonymous, 1985). The ventilation rate may have produced an increment in the amount of heat lost by the hens, which increased feed intake. The interaction of temperature and weeks (Table 3) was significant (P<.0001). The difference in consumption due to temperature between hens at 16.1 and 31.1 C was larger for the hens 16 wk into the experiment than during the 1st wk (22.6 versus 11.7 g). The interaction between dietary ME,, density and temperature was not significant (P>.25), but the interaction between dietary MEQ density and weeks into experiment (Table 4) was significant (P<.01). Differences in feed intake were small the 1st wk into the experiment and larger after that The regression obtained for predicting MEQ intake had an adjusted R2 of 99.65, a residual mean square of 16.97, and the number of observations used was 2,181. The prediction equation was MEn intake = (BW-75)(173.91 1.563 T) + 2.08 x EGM + 1.72 x BWCHD, where ME„ was in kilocalories per day, BW was in kilograms, T was the mean daily
temperature in C, EGM was in grams per day, and BWCHD was in grams per day. The standard errors for the coefficients were temperature = .0541, body weight (kg)-75 = 2.2719, egg mass (g/day) = .0501, and body weight change (g/day) = .1542. The high R2 value for the equation suggested the various independent variables produced a linear response in MEQ intake. The regression coefficients utilized for egg mass and body weight change for the hen production data were less than empirical values utilized for determining the maintenance requirement. Peguri and Coon (1988) reported temperatures from 7 to 37 C produced a quadratic response for feed intake, mean body weight, egg production, egg weight, and egg mass. The authors also showed a cubic response for the effect of temperature on mean body weight gain. The data reported herein contained effects of a smaller range of temperatures, thus producing a linear response. Feed intake was significantly decreased by the increase in energy density per kilogram of diet (Table 4). Dietary energy levels of 2,865
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76.1 79.5 86.8 101.6 101.7 993 114.0 102.3 108.1 106.4 1083 943 108.1 111.9 106.6 110.2 101.0b
130
PEGURI AND COON
TABLE 4. Effect of time and dietary ME„ density upon the feed intake of DeKalb White Leghorn layers from 20 to 36 wk of age * ME,,, kcal/kg Week
2,645
2,755
2,865
2,976
x2
76.8 76.2 80.5 93.9 100.0 1015 102.0 103.8 103.7 105.6 103.2 101.9 105.2 106.2 103.1 106.0 98.1C
76.1 k 81.5* 84.8* 97.4 h 10338 105.3ef 106^* IMA"* 107.3^ 108.1bc 104.6% 104.7* 108.8b 110.6" lOS.l1* 110.1"
3
77.2 87.0 87.9 100.4 105.1 107.9 108.4 108.4 108.9 108.8 108.5 106.8 111.6 113.3 111.6 112.8 104a
76.1 82.4 85.8 99.0 105.3 107.2 107.1 109.5 109.2 109.1 107.7 106.1 110.3 113.6 109.9 112.0 103.2"*
Means within columns or rows with no common superscripts differ significantly (P<.05). rhe mean square error of the whole plot was 264.98 with 120 df, and for the split plot 29.80 with 2,025 df. 2 Means of 144 observations. 3 Means of 36 observations, ^ e a n s of 394 observations. lr
and 2,976 kcal MEn/kg significantly decreased feed intake compared with intake of pullets fed the diet containing 2,645 kcal MEn/kg. Daily dietary energy intake decreased 28 kcal (Table 5) between 27.8 and 31.1 C. The 1.23 g reduction in egg mass production between 27.8 and 31.1 C did not account for the much lower MEn intake at 31.1 C, indicating a lower maintenance requirement. The MEn intake at 31.1 C was about the same for all diets except for the lower intake of hens fed diets containing 2,645 kcal MEJkg. Increments in energy densities from 2,645 up to 2,865 kcal MEJkg significantly increased MEn intake (Table 5) from 2,645 kcal/ kg. The increase in energy density from 2,865 and 2,976 kcal MEn/kg of diet failed to further significantly increase MEn intake. The MEn intake of layers at 31 C was very similar for all energy diets except for the hens fed 2,645 kcal MEn/kg diet. The present research indicates the failure of higher energy diets to increase energy intake for layers in hot temperatures for diets above 2,755 kcal MEJkg. Morris (1968) concluded MEn intake by White Leghorns increases by 2 or 3% for each 10% increase in
dietary energy. Marsden et al. (1973) found a 5% increment in energy intake when dietary energy was increased from 2,600 to 2,865 kcal ME„/kg. A subsequent increase to 3,100 kcal MEn/kg from 2,865 kcal MEn/kg did not increase MEn intake of birds housed at 21 C; however, the 3,100 kcal MEn/kg diet increased intake at 15 C by 3% (Marsden et al, 1973). hi the present study, MEn intake was affected to a larger extent between 2,645 and 2,865 kcal MEn/kg (Table 3), results similar to those found by Marsden et al. (1973). The increment of ME,,, intake due to increments in energy density of 100 kcal MEn/kg diet follows the law of diminishing returns. The response to the increments in energy was curvilinear, MEj, = -1,112.3 + (.9454 x ED) - (.0001591 x ED2) where ED represents MEn for diets (kilocalories per kilogram). The MEn intake increased 3.30% between 2,645 and 2,755 kcal; 2.18% between 2,755 and 2,865 kcal MEn/kg; and only .48% between 2,865 and 2,976 kcal MEn/kg. The 6.51% increment in MEn intake for layers fed diets between 2,645 and 2,976 kcal was higher at moderate temperatures (16.1 to
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 3?*
131
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 5. Effect of dietary ME„ density and temperature on ME„ intake of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976 i*
16.1 295.9 311.3 312.2 315.5 309.2"
18.9 292.9 297.2 317.3 320.1 307.1"
22.2 277.8 283.9 299.1 295.3 289.0 b
25.0 (kcal/day)3 278.1 280.3 290.8 284.5 283.4 b
27.8
31.1
5?
264.2 279.8 272.9 287.1 276.0°
241.2 250.9 250.8 249.3 248.^
275.2C 284.3 b 290.5" 291.9*
27.8 C) compared with 3.35% at 31.1 C (Table 5). The increment response of 5.8% MEn intake was only marginally lower for layers housed at 16.1 to 27.8 C and fed diets between 2,645 and 2,865 kcal MEn/kg. Layers housed at 31.1 C and fed diets between 2,645 and 2,865 kcal MEn/kg showed approximately the same percentage increment of MEQ intake (3.98% increment versus 3.35) as layers fed the complete range of energy density diets. The data suggests MEn intake at 31.1 C cannot be increased significantly for layers fed energy density levels above 2,865 kcal MEn/kg. The research indicated that between temperatures from 16.1 to 27.8 C, a 1% increment in MEn density per kilogram with diets from 2,645 to 2,865 kcal MEn/kg resulted in a .7% increment of MEn consumption or .054 kcal for each kilocalorie added to the diet The interaction between dietary MEn density and temperature was not significant (P>.12). The interaction of temperature by weeks was significant (P<.001) because the difference in MEQ intake between the lowest and highest temperature was 32 kcal the 1st wk and 63 kcal the last week, indicating that the animals modified MEn intake to compensate for differences in temperature (Table 6). The interaction between weeks and energy density was also significant (P<.001) (Table 7). Differences in MEn intake due to energy density were large during the 1st wk, but they decreased with the adaptation of the birds to the diet The significant differences in egg production (Table 8) were due, at least in part, to chance; there was a lack of consistent trends
mat indicated specific effects of warm or cold temperatures. The results of the experiment reported herein confirm the report of Emmans (1974) that the rate of lay in White Leghorns fed equal quantities of nutrients is independent of temperature between 5 to 30 C. Percentage hen-day egg production in the present research was not related (P<.05) to energy density in the diet, in contrast with the finding of Marsden et al. (1987), indicating that egg output is significantly increased by higher energy densities. Interactions for MEn by temperature and MEn by week were not significant, but the interaction of temperature and time was highly significant (P<.01) (Table 9). The temperatures that reduced egg production showed a larger difference on performance during the first 3 wk, and then the egg production became similar later in the 16-wk trial. Egg weight was significantly decreased by higher temperatures (Table 10). Hens housed in cooler temperatures produced heavier eggs. Egg weight decreased significantly at 27.8 C (P<.05). Increasing temperature to 31.1 C significantly decreased egg weight by 1.82 g compared with eggs at 27.8 C. The largest decrease in egg weights was between 27.8 and 31.1 C. Emmans (1974) reported egg weights are depressed at temperatures above 25 C, which is in good agreement with the present research. The interaction of time and temperature (Table 11) was significant (P<.0001). The differences in egg weight were small in Week 1 between 16.1 and 31.1 C (39.1 g versus 39.7 g); however, the difference increased after the
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""^Means within columns or rows with no common superscripts differ significantly (P<05). ^ e mean square error of the whole plot was 2,086.8 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations.
132
PEGURI AND COON TABLE 6. Effect of time and temperature upon the MEn consumption of DeKalb White Leghorn layers from 20 to 36 wk of age * Temperature, C
Week
18.9
16.1
22.2
25.0
27.8
31.1
3? 214 n 229™ 2381 2731 291 h 296* 298 rf 302 cd 301 cde 304 bc 299 def 294* 306 b 310* 304 bc 309*
3
— (kcal/day)
219 264 245 288 323 335 319 347 319 339 312 318 333 336 324 326
242 256 249 300 303 323 308 332 320 322 312 323 332 329 321 341
214 232 240 284 291 305 302 298 308 306 307 305 307 311 295 317
214 223 244 285 286 279 320 287 303 299 305 265 303 314 299 309
207 220 221 258 290 284 286 284 296 290 297 288 292 302 302 299
187 183 229 224 251 247 253 262 263 266 260 265 266 271 280 263
309"
307 a
289 b
283 b
276 c
248 d
"""Means within columns or rows with no common superscripts differ significantly. *The mean square error of the whole plot was 2,086.8 wim 120 df; for the split plot, the mean square error was 2,316.14 with 2,025 df. 2 Means of 144 observations. 3 Means of 24 observations. 4 Means of 394 observations.
TABLE 7. Effect of time and dietary ME„ density upon the ME„ consumption of DeKalb White Leghorn layers from 20 to 36 wk of age i ME,,, kcal/kg Week
2,645
2,755
2,865
2,976
3? 214 n 229m 2381 2731 291 h 296f« 298®f 302 cd 301 cde 304 bc 299*1 294811 306 b 310* 304*° 309*
3
(kcal/day)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 5E4
204 230 232 265 278 285 287 287 288 287 287 282 295 299 295 298
209 227 236 272 290 295 295 301 301 300 297 292 303 312 303 309
214 234 243 275 296 299 307 310 308 311 305 298 310 313 309 314
228 227 240 279 298 302 304 309 309 314 307 303 313 316 307 309
275 c
284 b
290*
283 b
""""Means within columns or rows with no common superscripts differ significantly (P<05). ^ h e mean square error of the whole plot was 2,086.8 with 120 df and for the split plot 236.14 with 2,025 df. 2 Means of 144 observations. 3 Means of 36 observations. 4 Means of 394 observations.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 3E*
133
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 8. Effect of dietary ME„ density and temperature on hen-day egg production of DeKalb White Leghor, layers from 20 to 36 wk of age * Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976 5*
16.1
18.9
22.2
25.0
27.8
31.1
3?
81.59 83.27 81.46 83.85 82.52 bc
82.40 83.71 86.43 81.68 83.05 abc
82.56a 83.15" 83.36* 82.66a
- (%)3 83.01 81.39 83.04 80.13 si^1*
84.06 85.71 84.78 84.74 84.82a
80.67 81.46 83.09 81.02 81.56°
83.61 83.33 83.38 84.51 83.71 ab
a_c
2,645 and 2,865 kcal MEJkg diets. No significant difference was observed in egg weights between hens fed 2,755 and 2,976 kcal MEn/kg diet. Egg weight was not increased by increased dietary MEQ density for hens housed at or above 27.8 C. The interactions of ME„
3rd wk of the experiment, and at 16 wk, it was 3.5 g (58.5 g versus 55.0 g). An increase in energy density significantly increased egg weight (Table 10) in agreement with results of Marsden et al. (1987). Average egg weight differed by .8 g between hens fed
TABLE 9. Effect of time and temperature upon the hen day egg production of DeKalb White Leghorn layers from 20 to 36 wk of age1 Temperature, C Week
16.1
18.9
22.2
27.8
31.1
3?
11.4 37.7 64.5 86.6 89.9 94.0 93.6 94.2 92.7 92.4 92.2 86.1 90.8 93.3 92.9 92.8
10.4 38.2 62.5 87.4 935 94.8 94.6 94.8 93.8 92.9 93.5 92.8 92.8 93.1 93.1 92.7
U.4 h 37.98 67.9* 87.0° 92.1 d 94.4 ab 94.3 ab 94.7a 94.1 abc 93.9 abc 93.9 abc 92.2 d 92.9°* 93.4 abcd 93.5"*° 93.2 bcd
81.6°
82.5 bc
13.2 36.7 67.4 91.8 93.0 93.2 92.8 94.0 94.2 93.5 94.1 93.5 92.4 93.0 93.5 92.7 KiXf**
25.0 (fnl 3
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
J* a-fai
8.7 32.7 675 83.5 90.8 94.2 93.2 93.3 93.9 94.4 94.0 92.9 93.4 92.3 93.1 92.9
13.6 40.5 71.9 87.7 93.4 94.9 95.9 96.4 96.4 95.0 95.4 94.9 95.3 95.3 95.7 95.0
si^
84.8"
11.1 41.9 73.6 85.1 92.5 95.3 95.4 95.5 93.9 95.2 94.4 92.9 93.0 93.4 92.9 93.4 g37ab
'Means within columns or rows with no common superscripts differ significantly (P<05). 'The mean square error of the whole plot was 114.72 with 120 df and for the split plot 32.72 with 2,025 df. •'Means of 144 observations. 3 Means of 36 observations. Means of 394 observations.
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Means within columns or rows with no common superscripts differ significantly (P<.05). 'The mean square error of the whole plot was 192.64 with 120 df. Means of 576 observations. 3 Means of 96 observations. Means of 386 observations.
134
PEGURI AND COON
TABLE 10. Effect of dietary ME„ density and temperature on average egg weight of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C ME,,
16.1
(kcal/kg) 2,645 2,755 2,865 2,976 5*
52.36 53.63 53.15 54.49 53.41 a
18.9 52.81 52.73 54.35 53.33 53.31*
22.2
25.0
51.62 52.11 53.52 52.36 52.40 bc
M3 uw52.93 52.40 53.21 53.51 52.02^
27.8
31.1
5?
51.37 52.71 51.73 52.36 52.05°
50.39 50.29 50.19 50.06 50.23 d
51.91 b 52.31 ab 52.69" 52.69°
a-di
Means within columns or rows with no common superscripts differ significantly (P<05). rhe mean square error of the whole plot was 23.326 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations. lr
the present experiment. Amino acid intake for hens at each temperature was that recommended by Harms (1983) or higher, suggesting differences in egg weight are not due to amino acid levels but to the level of energy intake, particularly above 25 C. The diets were
TABLE 11. Effect of time and temperature upon the egg weight of DeKalb White Leghorn layers from 20 to 36 wk of age * Temperature, C Week
16.1
18.9
22.2
25.0
27.8
31.1
3?
40.5 45.6 47.0 49.5 51.1 52.0 52.9 53.2 54.0 53.9 54.7 54.9 55.3 55.8 56.0 56.4
39.7 43.3 46.6 47.3 49.7 49.9 50.7 51.1 51.5 51.9 52.5 52.8 53.4 53.9 54.6 55.0 50.2 d
39.91 44.9 k 47.7J 49.51 52.7 h 53.5« 53.7f 54.3 f 54.7* 55.1 e 55.2 d 55.7 d 55.2C 56.3 b 56.7"* 56.9"
(r& V&)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 i*
39.1 44.4 48.3 49.7 52.4 53.4 55.2 55.1 55.8 56.2 56.4 56.7 57.2 57.7 58.4 58.5 53.4 a
40.4 46.1 48.6 49.8 52.7 53.5 54.4 54.9 55.4 55.5 56.1 56.7 56.3 57.1 57.3 58.1 53.3 a
38.2 44.8 47.8 50.5 51.1 52.8 53.9 54.0 54.8 54.8 55.1 55.6 55.8 55.9 56.7 56.7 53.0 ab
41.4 45.3 48.0 50.5 52.6 545 54.1 54.2 54.6 55.8 55.7 54.9 56.0 57.5 57.1 56.5 52.4 be
52.0°
"Means within columns or rows with no common superscripts differ significantly (P<05). lr The mean square error of the whole plot was 23.32 with 120 df and for the split plot 3.168 with 2,303 df. 2 Means of 144 observations. 3 Means of 36 observations. 4 Means of 394 observations.
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density and temperature (P>.12) and MEQ density and week (P>.22) were not significant. Payne (1967) indicated that at 30 C, birds fed very high energy diets overcame the egg weight depression that occurred in hens fed lower energy diets. That was not the case in
135
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
TABLE 12. Effect of dietary MEn density and temperature on mean body weight of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C M^ (kcal/kg) 2,645 2,755 2,865 2,976
*
16.1 1.537 1.601 1.603 1.620 1.590*
18.9 1.537 1.510 1.618 1.614 1.569b
22.2 1.509 1.508 1.544 1.556 1.532c
25.0 (kg)3 1.490 1502 1530 1.538 1.515d
27.8
31.1
5?
1.440 1.515 1.462 1510 1.483*
1.348 1.399 1.408 1.405 1.390*
1.478d 1.506° 1.529b 1.540"
formulated to provide adequate levels of calcium, protein, and amino acids for expected low intakes for hens housed in hot temperatures. The protein and amino acids also had to be adjusted on a therm basis to provide hens equivalent daily intakes of protein and amino acids with various energy density levels in experimental feeds. Mean body weights decreased linearly between 16.1 and 27.8 and abruptly decreased at 31.1 C (Table 12), indicating the difficulty the birds housed at 31.1 C had to increase thenbody weight when compared with birds at cooler temperatures. The body weight change followed the same trends (Table 13); average body weight and gain were the lowest at 31.1 C. Energy density had a significant effect on both mean body weight and daily body weight gain. The higher the energy content of the ration, the heavier the birds and the higher the body weight gain. The MEn by temperature interaction was not significant for weight or gain. The temperature by week interaction was significant for mean weight (P<.001) and for weight gain (P<01). The hens housed in hotter temperatures during the 2-wk acclimation period were slightly lighter at 20 wk of age than hens housed in cooler temperatures. The layers' mean weight and gain, however, were further apart at 36 wk of age because of the large difference in MEn consumption for the 16-wk period (Table 3). Higher dietary MEn density diets improved feed conversion significantly (Table 14). The higher the MEn level in the diet, the better the feed conversion. Feed conversion improved an
average of .0273 g feed/g egg mass for each degree of increase in temperature. Dietary MEn density improved feed conversion .05 g feed per gram of egg mass for each 100 additional kilocalories of MEn per kilogram of diet. Feed conversion was significantly improved between 27.8 and 31.1 C. Feed conversion was optimal at 31.1 C for hens fed the highest levels of dietary MEn m m e diet. However, egg weights were depressed by about 2 g at 31.1 C compared with those of hens at 27.8 C. The most adequate practice to maximize egg size and feed conversion for young hens may be to keep hens at 27.8 C or below until an adequate egg size is obtained and then increase the house temperature to 31.1 C. The interaction of MEQ and temperature was not significant Maintenance energy requirement decreased 2.21 kcal MEn/kg of body weight per Celsius degree increase in temperature between 18.9 and 22.2 C (Table 15). The rate of decrease was .10 kcal MEn/kg of body weight per Celsius degree between 22.2 and 25.0 C. The change in maintenance requirement was .55 kcal MEn/kg of body weight per Celsius degree between 25 and 27.8 C. Maintenance requirement decreased 2.84 kcal MEn/kg of body weight per Celsius degree between 27.8 and 31.1 C. The present research indicated the maintenance requirement for energy was higher at cold temperatures, reached a plateau between 22.2 and 27.8 C, and decreased sharply at 31.1 C. Coon and Peguri (1985) suggested the maintenance requirement for hens was approximately 60% of the MEn
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on May 13, 2014
"Means within columns or rows with different superscripts differ significantly (P<05). 'The mean square error of the whole plot was .04592 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations.
136
PEGURI AND COON
TABLE 13. Effect of dietary MEn density and temperature on mean body weight gain of DeKalb White Leghorn layers from 20 to 36 wk of age Temperature, C ME„ (kcal/kg) 2,645 2,755 2,865 2,976
i4
16.1
18.9
22.2
2.72 3.17 2.97 3.29 3.04a
2.41 2.62 3.12 2.90 2.76b
2.86 2.71 2.72 2.87 2.79 ab
25.0
27.8
31.1
5?
2.14 2.33 2.46 2.50 2.36°
1.88 1.79 1.91 2.17 1.94d
2.34 b 2.51 ab 2.61* 2.73 a
f irMmrr'
2.30 2.41 2.48 2.64 2.46c
a_d
TABLE 14. Effect of dietary ME„ density and temperature on feed conversion of DeKalb White Leghorn layers between 20 to 36 wk of age 1 Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976
#
16.1
18.9
22.2
25.0
27.8
31.1
i2
2.57 2.60 2.47 2.42 2.52 a
2.50 2.39 2.40 2.38 2.41 b
2.43 2.37 2.34 2.24 2.34°
2.46 2.38 2.29 2.20 2.33 c
2.38 2.31 2.26 2.19 2.28 d
2.19 2.16 2.06 2.04 2.1 l e
2.42 a 2.37b 2.3 l c 2.25d
"Means within columns or rows with no common superscripts differ significantly (P<05). 1 The mean square error of the whole plot was .1093, with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. 4 Means of 386 observations.
TABLE 15. Effect of dietary ME„ density and temperature on maintenance ME requirement of DeKalb White Leghorn layers from 20 to 36 wk of age 1 Temperature, C ME,, (kcal/kg) 2,645 2,755 2,865 2,976
**
16.1
18.9
22.2
25.0
27.8
31.1
5?
99.38 103.40 102.50 102.90 102.00"
97.38 98.86 101.20 105.80 100.80*
88.71 92.87 97.30 95.15 93.78b
92.82 93.67 95.98 92.65 93.5 l b
89.45 90.98 91.89 95.59 91.98 b
80.69 84.32 82.26 83.10 82.59°
91.41 b 94.01* 95.20* 95.87*
'"Means within columns or rows with different superscripts are significantly different (P<05). 'The mean square error of the whole plot was 413.48, with 120 df. 2 Means of 576 observations. Means of 96 observations. Means of 386 observations.
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Means within columns or rows with no common superscripts differ significantly (P<05). The mean square error of the whole plot was 3.68 with 120 df. 2 Means of 576 observations. 3 Means of 96 observations. ''Means of 386 observations. 1
TEMPERATURE, DIETARY ENERGY, AND LAYER PERFORMANCE
REFERENCES Anonymous, 1985. DeKalb's Breeder Guide. DeKalb Poultry Research, Inc., DeKalb, IL. Association of Official Analytical Chemists, 1984. Official Methods of Analysis. 14th ed. Association of Official Analytical Chemists, Washington, DC. Coon, C. N., and A. Peguri, 1985. Predicting feed intake for layers. Pages 103-112 in: Proceedings of the 46th Minnesota Nutrition Conference, St Paul, MN.
Davis, R. H., D.E.M. Hassan, and A. H. Sykes, 1972. The adaptation of energy utilization in the laying hen in relation to ambient temperature. J Agric. Sci. 79: 363-369. Davis, R. H., DJB.M. Hassan, and A. H. Sykes, 1973. Energy utilization in the laying hen in relation to ambient temperature. J. Agric. Set Camb. 21: 173-177. Etrurians, G. C , 1974. The effects of temperature on the performance of laying hens. Pages 79-90 in: Energy Requirements of Poultry. T. R. Morris and B. M. Freeman, ed. British Poultry Science Ltd., Edinburgh, Scotland, UJC. De Groote, G., 1974. Utilization of metabolizable energy. Pages 113-133 in: Energy Requirements of Poultry. T. R. Morris and B. M. Freeman, ed. British Poultry Science Ltd., Edinburgh, Scotland, UJC. Harms, R. H., 1983. Commercial layer management should be adjusted for strain and season. Feedstuff's 55(40):65. Huyghebaert, G., G. DeMunter, and G. De Groote, 1989. Energy expenditure of laying hens under different lighting patterns. Pages 255-258 in: Energy Metabolism of Farm Animals. Y. van der Honing and W. H. Close, ed. Proceedings of 11th Symposium, Lutheran, Netherlands. PUDOC, Wageningen, Netherlands. Marsden, A., T. R. Morris, and A. S. Cromarty, 1987. Effects of constant environmental temperatures on the performance of laying pullets. Br. Poult Sci. 28: 361-380. Marsden, A., E. Wetbli, N. Kinread, and T. R, Morris, 1973. The effect of environmental temperatures on feed intake of laying hens. World's Poult. Sci. J. 29: 286-287. McDonald, M. W., 1978. Feed intake of laying hens. World's Poult. Sci. J. 34:209-221. Morris, T. R., 1968. The effect of dietary energy level on the voluntary caloric intake of laying hens. Br. Poult. Sci. 9:285-295. National Research Council, 1984. Nutrient Requirements of Poultry. 8th ed. National Academy of Sciences, Washington, DC. Payne, C. G., 1964. The influence of environmental temperature on poultry performance. Pages 117-120 in: 2nd European Poultry Conference, Bologna, Italy. Payne, C. G., 1966a. Practical aspects of environmental temperature for laying hens. World's Poult Sci. J. 22:126-139. Payne, C. G.. 1966b. Developments in the use of artificial heating for the control of the animal environment Report of the Rural Electrification Conference, 1966. Electricity Council, London, England. Payne, C. G., 1967. Environmental temperature and egg production. Pages 235-241 in: The Physiology of the Domestic Fowl. C. Horton-Smith and E. C. Amoroso, ed. Oliver and Boyd, Edinburgh, Scotland, UJK. Peguri, A., 1987. Energy requirements of the laying hen. PhX>. Dissertation, University of Minnesota, St Paul, MN. Peguri, A., and C. Coon, 1988. Development and evaluation of prediction equations for metabolizable and true metabolizable energy intake for the DeKalb XL-Link White Leghorn hen. Pages 199-211 in: Proceedings of the 49th Minnesota Nutrition Conference, St Paul, MN. Peguri, A., and C. N. Coon, 1989. The efficiency of
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consumed based on a multiple regression of production data at various environmental temperatures. The MEQ requirements for maintenance determined in the present study were approximately 50% of ME,, consumed, because the MEu required for egg mass and body weight were based on higher ME„ empirical values (Peguri and Coon, 1989). De Groote (1974) reviewed eight reports and stated that maintenance requirements varied between 99 and 133 kcal/BW-75 per day, depending upon age and environmental temperature. Maintenance requirements in the research reported herein ranged from 82.6 to 102 kcal MEn/kg body weight for young hens housed in temperatures ranging from 16.1 to 31.1 C. De Groote (1974) also reported 64 to 86% efficiency of utilization for MEn for egg production. Huyghebaert et al. (1989) reported a large range of MEQ efficiency for utilization of .5 to .8, depending on genetic, environmental conditions, and methods of calculations. The MEQ efficiency of utilization of .5 for production utilized to determine maintenance requirements is within the lower portion of the reported range of ME„ efficiencies. Peguri and Coon (1989) reported the mean MEQ efficiency of utilization for maintenance was .61 for temperatures 7.2 C to 35 C. Reid et al. (1978) stated the efficiency of utilization of MEn was 62% for maintenance and 63% for production. The researchers utilized 5 kcal/g for body weight change and 1.6 kcal/g egg mass instead of 3 kcal/g for body weight gain and 1.42 kcal/g egg mass reported by Peguri (1987). Maintenance requirement for energy appeared to increase with dietary energy density (Table 15). A possible explanation is that the efficiency of utilization of feed energy for egg production and body weight gain may decrease as energy density increases in the diet, or alternatively the amount of energy required per unit of body weight gain may increase as the energy concentration per kilogram of diet is increased.
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PEGURI AND COON onmental temperature and rationing treatments on the productivity of pullets fed on diets of differing energy content. Rhod. J. Agric. Res. 10:3-21. Smith, A. J., and J. Oliver, 1972b. Some nutritional problems associated with egg production at high environmental temperatures. 4. The effect of prolonged exposure to high environmental temperatures on the productivity of pullets fed on high energy diets. Rhod. J. Agric. Res. 10:43-60. Steel, R.G.D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, New York, NY. Weisberg, S., 1980. Applied linear regression. John Wiley and Sons, New York, NY. Wilson, W. O., T. Siope, P. Ingkasuwan, and F. B. Mather, 1972. The interaction of temperature of 21 C and photoperiod of 8 and 14 hours on White Leghorn hens' production. Arch. Geflugelkd. 37:41-45.
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utilization of dietary energy for layers and the law of diminishing returns. Pages 270-299 in: Proceedings of the 50th Minnesota Nutrition Conference, St. Paul, MN. Polin, D., 1983. The influence of environmental temperature on the feed intake of laying hens examined. Feedstuffs 55(5):21-22. Reid, B. L., ML E. Valencia, and P. M. Maiorina, 1978. Energy utilization by laying hens. 1. Energetic efficiencies of maintenance and production. Poultry Sci. 57:461-465. SAS Institute, 1982. SAS® User's Guide: Statistics. SAS Institute Inc., Cary, NC. Sibbald, I. R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poultry Sci. 55:303-308. Smith, A. J., and J. Oliver, 1972a Some nutritional problems associated with egg production at high environmental temperatures. 1. The effect of envir-