- Email: [email protected]
The Effects of Feed and Water Withdrawal and Holding Shed Treatments on Broiler Yield Parameters
The Effects of Feed and Water Withdrawal and Holding Shed Treatments on Broiler Yield Parameters B. S. BENIBO and A. J. FARR 1 Department of Poultry Science, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803 (Received for publication June 12, 1984)
1985 Poultry Science 64:920-924
INTRODUCTION
Poultry producers have used feed or both feed and water withdrawal as a method to improve yield by controlling contamination and broiler live shrinkage. Considerable research has been done in this area, and the reports generally indicate that extended withdrawal periods of feed or feed and water tend to reduce poultry yield through increased live shrinkage. May and Brunson (1955), Brunson (1957), and Wabeck (1972) have shown that 24-hr withdrawal period resulted in significantly lower eviscerated yields. Henry and Raunikar (1958), Snyder and Orr (1964), Wabeck (1972), and Salmon (1979) have reported increased rate of live weight shrinkage as feed and water withdrawal periods increased. Thomson et al. (1961) observed that smaller dry carcasses absorb proportionately more moisture than do heavier carcasses during chilling, and Brunson (1957) reported that withdrawal treatment did not affect carcass moisture absorption from chilling. Marion et al. (1970) reported that an elevated holding temperature resulted in a significant increase in live shrinkage for turkeys.
1
To whom correspondence should be addressed.
However, little work has.been reported on how withdrawal periods and the provision of environmental comfort during holding prior to slaughter affects broiler yield and live body shrinkage especially in hot months of the year. Air-conditioning (A/C), fogging and fanning (FF), fanning (F), and evaporative cooling (E/C), were used as heat-reducing methods during holding in summer together with 3 feed and water withdrawal periods (10, 15, and 20 hr) prior to slaughter to determine the effects on broiler yield parameters. MATERIALS AND METHODS
Eight trials involving 960 broilers with 120 birds per trial (60 males, 60 females) were conducted during the summer months. Day-old chicks secured from a commercial source were grown on a standard broiler ration to 52 to 58 days of age on the Louisiana State University Agricultural Center Poultry Research Farm. For each withdrawal period, feed and water were removed from pens and 20 birds of each sex were individually identified, weighed (farm weight), marked on the back with paint (color by period), and placed back into the original pens. The 20-, 15-, and 10-hr treatment groups were held in the pens for 14, 9, and 4 hr, respectively and weighed again (pen weight).
920
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
ABSTRACT Eight trials were conducted using broiler chickens between 52 to 58 days of age to study the effect of 10, 15, and 20 hr of feed and water withdrawal periods and five environmental holding shed treatments [open shed, air-conditioning (A/C), fanning and fogging (FF), fanning (F), and evaporative cooling (E/C)] on broiler yield parameters. Twelve birds of each sex were used for each withdrawal and shed combination making a total of 120 birds per trial. Live weight shrinkage increased with increasing length of withdrawal and male birds showed the highest weight loss. Dressed and chilled carcass weights, eviscerated yield, and chilled carcass yield based on farm weight decreased significantly with each increase in withdrawal period. The A/C, FF, F, and E/C sheds significantly reduced live shrinkage and improved broiler yields when compared with the open shed treatment. Preslaughter treatments did not influence carcass moisture uptake during chilling. (Key words: live shrinkage, yield, withdrawal time, holding shed)
921
WITHDRAWAL AND HOLDING EFFECTS ON YIELD
of birds to the environmental house to activate the dew cell elements. Dew cell element temperature (DC) was converted to dew point temperature (Tdp) and the temperature-humidity index (ThI) determined as given by Esmay (1969) with the following relationships: Tdp = -18.94607 + (.1803729 X DC) + (.00603709 X DC 2 ) - (.00002771 X DC 3 ) + (.0000004 X DC 4 )
[1]
ThI = .55 X Tdb + .02 X Tdp + 17.5
[2]
Birds were held in the environmental rooms for 6 hr and weighed again prior to slaughter (slaughter weight). Shed shrinkage was determined as the difference between pen weight and slaughter weight. The birds were then exsanguinated, scaled for 90 sec at 54 to 55 C, defeathered for 45 sec in an automatic feather picker, and carefully eviscerated, attempting to standardize cuts. Weights were taken for dressed carcass minus neck (carcass weight) prior to chilling and after chilling and 7 min of drip time (chilled carcass weight). A split-split plot arrangement of treatments in a randomized block design with trials as blocks, shed treatment being the main plot, feed and water withdrawal periods the splitplot, and sexes as the split-split plot was used for the study. Statistical analyses were carried out on data sexes separate and on a straight-run (SR) basis
TABLE 1. The effect of feed and water withdrawal periods on percent pen shrinkage and percent shed shrinkage Least square means period Pen
Shed shrin kage
Pen shrinkage Shed
1
Female
Male
SR
1.55 c
1.71 c
1.63c
3.96 b
4.02 b
3.99 b
5.23 a
5.66 a
5.45 a
.06
.08
.05
(hr)
Female
Male
SR1
1.87*
2.05 a
1.96 a
1.55 b
1.79 a
1.67 b
1.43 b
2.11 a
1.77 ab
.06
.15
.08
' (%)
4 6 9 6 14 6 SE
' ' Means in same column with different superscripts are significantly different (P<.01). 1
Straight-run birds.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
Four males and 4 females per withdrawal treatment were placed in coops and 2 males and 2 female filler birds added to maintain a 12-bird density before being transferred to the environmental treatment sheds. The five treatment sheds (rooms) were as follows: 1) an open shed (control), 2) an A/C room, 3) FF room, 4) F room, and 5) an E/C room. Each room was 22.52 m 3 (2.41 m long X 3.91 m wide X 2.39 m high) and completely sealed from an adjacent room with plywood and glass wool insulation. The open shed had three sides completely open and shared a common side with the A/C room, which was maintained at 19.4 C. The south side of the E/C room was covered with glass wool wick material (screen) with four F-80 fogging nozzles installed at 45°C angle above the screen and spraying 7.5 liter of the water per nozzle/hr at 22.5 kg pressure, continuously. The south sides of FF and the F rooms were open. A venturi type, 206 cfm fan was installed on the north side of both the FF and F sheds, blowing air over the birds, and the E/C room pulled (negative pressure) cool moist air across the birds. An F-80 fogging nozzle (as described) was installed 21 cm below but in front of the fan in the FF room. A Honeywell recorder connected in series to a Foxboro dew cell element (positioned at coop level) registered the dew cell element and dry bulb temperature (Tdb) in each room at intervals of 2 min between recordings. The A/C unit, foggers, fans, and Honeywell recorder were started 24 hr prior to arrival
922
BENIBO AND FARR TABLE 2. The effect of feed and water withdrawal periods on dressed carcass weight and chilled carcass weight Least square means
Withperiods
Chilled1 carcass weight
Dressed carcass weight Female
Male
SR1
1033 a 1013 b 1008 b
1263 a 1233 b 1215 c
1147 a 1122b llllc
(hr)
SE
SR1
1167 a 1151 b 1148 b
1387 a 1362 b 1343 c
1276 a 1257 b 1245 c
(g)
3
1
Male
3
5
2
4
5
' ' Means in same column with different superscripts are significantly different (P<.01). Straight-run birds.
with farm weight as a covariate, and applying least square regression as outlined in SAS by Helwig and Council (1979). Differences in treatments were separated by use of the PDIFF (Probability of Differences) option of the general linear models procedure.
feed in the digestive tract provided nutrients and energy at the beginning of withdrawal but with extended withdrawal body tissue was metabolized for these supplies, resulting in lower carcass weights and yields. Differences in
RESULTS AND DISCUSSION The percent pen shrinkage increased significantly with each increment in feed and water withdrawal period for male and SR birds (Table 1). These findings are consistent with those reported by Henry and Raunikar (1958), Snyder and Orr (1964), Wabeck (1972), and Salmon (1979). Withdrawal periods influenced percent shed shrinkage in female and SR birds but did not affect this parameter in male birds. Females receiving 10-hr withdrawal treatment had a higher percent shed shrinkage than did 15- and 20-hr treatment birds, which did not differ, suggesting that a higher rate of weight loss at early hours of withdrawal (attributable partly to emptying of digestive tract) was the influencing factor. Each increasing increment in withdrawal period resulted in lower dressed and chilled carcass weights and dry eviscerated and chilled carcass yield for male and SR birds (Tables 2 and 3). This agrees with the results of May and Brunson (1955), Brunson (1957), and Wabeck (1972), and the trend indicates significant edible losses in yield with prolonged withdrawal periods. The losses were a reflection of significant differences in live weights with time in these birds. Salmon (1979) has postulated that
TABLE 3. The effect of feed and water withdrawal periods on eviserated yield, chilled carcass yield, and percent moisture uptake With-
Least square means SR1
periods
Female
10 15 20 SE
63.99 a 62.79 b 62.54 b .16
10 15 20 SE
72.28 A 71.27 B 71.17 B .29
Chilled carcass yield 70.42 A 71.33 A 70.21 B 69.13 B 69.67 c 68.16c .27 .20
10 15 20 SE
12.95 A 13.59 A 13.82 A .38
Percent moisture uptal 9.90 A 11.42 B 12.08 A 10.54 A A 12.20 A 10.58 .25 .38
Male Dry eviscerated yield 64.07 a 62.53 b 61.64 c .16
64.02 a 62.65 b 62.10 c .12
a,b,c Means in same column with different superscripts are different (P<.01). A,B,CMeans in same column with different superscripts are different (P<.05). 1 Straight-run birds.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
10 15 20
Female
WITHDRAWAL AND HOLDING EFFECTS ON YIELD
923
TABLE 4. Means and ranges for dry bulb temperatures, dew point temperatures, and temperature-humidity indexes (ThI) in the holding shed
Holding shed
Mean dry b u l b temperature
range
Open A/C2 FF3-4 Fan E/C5
28.6 19.4 22.8 25.9 24.2
2 6 . 1 - -30.6 1 8 . 9 - -20.6 2 2 . 2 --24.4 2 3 . 9 --27.8 2 2 . 8 - -25.6
Temperaturehumidity index1
Mean dew p o i n t temperature
Rangi
Mean
Range
23.2 12.9 20.5 21.7 22.2
2 2 . 2 --25.0 1 1 . 1 --13.9 1 8 . 3 --22.2 1 9 . 4 --22.8 2 0 . 5 - -23.3
78.2 65.2 71.7 74.9 73.5
7 6 --81 6 4 --68 7 0 --73 7 3 --77 7 2 --75
(.c;
ThI = .55 X (dry bulb temperature) + .2 X (dew point temperature) + 17.5. Air-conditioned.
3
Fan and fogger.
4
Values for only three trials.
5
Evaporatively cooled.
carcass weights and yield did not occur for females in the 15- and 20-hr treatment groups, because live weight losses stabilized for these birds in the same periods. The withdrawal treatments did not influence moisture uptake in the chiller for the male and female birds, which agrees with findings of Salmon (1979) and Brunson (1957). Females absorbed more moisture expressed on absolute or percentage basis than did males (Table 3). However, when the sexes were pooled in analysis as SR, a greater uptake of moisture was found for the 15- and 20-hr withdrawal treatments. Prevalent environmental conditions in the holding sheds are presented in Table 4. Only three trials were used in the FF shed treatment due to a dew cell recorder malfunction. Mean Tdb and Tdp were consistently higher in the open shed with resultant higher ThI during all trials. It may be noted that ThI is an indication of level of discomfort and an empirically determined index weighting Tdb and Tdp for comparison with animal performance. Correlation coefficients of Tdb and Tdp and ThI with percent shed shrinkage were .6985, .4900, and .6955, respectively. Thus, one may attribute part of the higher live shrinkage to holding temperature (through dehydration) in the open shed as suggested by Marion et al. (1970). Heat moderation by A/C and FF were superior to F and E/C for females but not different for males (Table 5).
TABLE 5. The effect of environmental holding shed on percent shed shrinkage, dressed carcass weight, and chilled carcass weight Environmental holding shed
Female
Open A/C2 FF3 Fan E/C4 SE
2.59a 1.19 c 1.26 c 1.55b 1.48b .07
Open A/C FF Fan E/C SE
1005b 1022a 1026a 1018a 1019a 3
Open A/C FF Fan E/C SE
B
Least square m e a n Male
SR 1
Percent shed shrinkage 3.61a 1.35b 1.40 b 1.86b 1.71b .20
3.10a 1.28d 1.33cd 1.70b 1.60bc .11
Dressed carcass w eight (g) 1215b 1245a 1241a 1243a 1238a 4
HOOb 1133a 1132a 1131a 1128a 3
Chilled carcass weight (g) 1344B 1373A 1369A 1373A 1362A 7
1136 1166A 1158A 1158A 1159A 7
1240B 1268A 1263A 1265A 1260A 5
' ' ' Means in same column with different superscripts are different (P<.01). AB ' Means in same column with different superscripts are different (P<.05). 1
Straight-run birds.
3
2
Air-conditioned.
' Evaporatively cooled.
Fan and fogger.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
1 2
924
BENIBO AND FARR
TABLE 6. The effect of environmental holding shed on yield, chilled carcass yield, and moisture uptake Environmental holding shed
Female
Least square means Male SR1 Dry eviscerated yieldI
b
62.29 63.35 a 63.52 a 63.13 a 63.17 a .28
Open A/C FF Fan E/C SE
70.42 A 72.25 A 71.73 A 71.74 A 71.73 A .37
Open A/C FF Fan E/C SE
13.10 A 14.04 A 12.93 A 13.64 A 13.53 A .49
61.68b 63.17a 62.99 a 63.09 a 62.80 a .21
62.00 b 63.25 a 63.25 a 63.12 a 62.99a .15
Chilled carcass yield 68.19 B 69.64 A 69.50 A 69.64 A 69.17 A .35
REFERENCES 69.33 B 70.94 A 70.60 A 70.7O A 70.46 A .26
ercent moisture uptalKe 10.59 A 10.28 A 10.38 A 10.38 A 10.13 A .42
———
11.86 A 12.16 A 11.62 A 12.02 A 11.84^ .32
' Means in same column with different superscripts are different (P<.01). AB ' Means in same column with different superscripts are different (P<.05). 1
Straight-run birds.
2
Air-conditioned.
3
Fan and fogger.
4
Evaporatively cooled.
Dressed carcass weights, dry yield, and chilled carcass yield based o n farm weight were significantly lower in t h e open shed than in t h e
Branson, C. C , 1957. Effect of length of fasting period with subsequent ice-chilling on eviscerated yield and moisture content of broiler carcasses. Poultry Sci. 36:1107. (Abstr.) Esmay, M. L., 1969. Page 101 in Principles of Animal Environment. Avi Publ. Co., Inc. Helwig, J. T., and K. A. Council, 1979. Statistical Analyses System Users' Guide. SAS Inst. Inc., Raleigh, NC. Henry, W. R., and R. Raunikar, 1958. Weight losses of broilers during the live haul. North Carolina Agric. Econ. Inf. Ser. No. 69. Marion, W. W., R. A. Jungk, and S. T. Maxon, 1970. Influence of handling and processing on weights and yields of turkey meat. Food Technol. 24: 924-926. May, K. N., and C. C. Brunson, 1955. Effect of starvation period on eviscerated yields of broilers. Poultry Sci. 34:1210. Salmon, R. E., 1979. Effect of food and water deprivation on live weight shrinkage, eviscerated carcass yield and water absorption during chilling of turkey carcasses. Br. Poult. Sci. 20:303-306. Snyder, E. S., and H. L. Orr, 1964. Pages 4 3 - 4 8 in Poultry meat: processing, quality factors, yields. Ont. Dept. Agric. Publ. 9. Thomson, J. E., A. W. Kotula, and J. A. Kinner, 1961. The effect of temperature and time of prechill on total moisture absorption by fryer chickens. Poultry Sci. 40:1139-1142. Wabeck, C. J., 1972. Feed and water withdrawal time relationship to processing yield and potential fecal contamination of broilers. Poultry Sci. 51: 1119-1121.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
Open A/C 2 FF 3 Fan E/C4 SE
A/C, F F , F , and E/C r o o m s and these were n o t different from o n e a n o t h e r (Tables 5 and 6). Again, this was reflected b y higher holding t e m p e r a t u r e and p e r c e n t live shrinkage for birds held in t h e o p e n shed. Thus, decreasing t h e ThI during t h e holding period m a y be a key t o improving broiler yield and reducing live b o d y skrinkage. Holding shed t r e a t m e n t did n o t influence moisture u p t a k e during chilling; however, in each shed females absorbed m o r e m o i s t u r e t h a n males on b o t h an absolute and a percentage basis.
1985 Poultry Science 64:920-924
INTRODUCTION
Poultry producers have used feed or both feed and water withdrawal as a method to improve yield by controlling contamination and broiler live shrinkage. Considerable research has been done in this area, and the reports generally indicate that extended withdrawal periods of feed or feed and water tend to reduce poultry yield through increased live shrinkage. May and Brunson (1955), Brunson (1957), and Wabeck (1972) have shown that 24-hr withdrawal period resulted in significantly lower eviscerated yields. Henry and Raunikar (1958), Snyder and Orr (1964), Wabeck (1972), and Salmon (1979) have reported increased rate of live weight shrinkage as feed and water withdrawal periods increased. Thomson et al. (1961) observed that smaller dry carcasses absorb proportionately more moisture than do heavier carcasses during chilling, and Brunson (1957) reported that withdrawal treatment did not affect carcass moisture absorption from chilling. Marion et al. (1970) reported that an elevated holding temperature resulted in a significant increase in live shrinkage for turkeys.
1
To whom correspondence should be addressed.
However, little work has.been reported on how withdrawal periods and the provision of environmental comfort during holding prior to slaughter affects broiler yield and live body shrinkage especially in hot months of the year. Air-conditioning (A/C), fogging and fanning (FF), fanning (F), and evaporative cooling (E/C), were used as heat-reducing methods during holding in summer together with 3 feed and water withdrawal periods (10, 15, and 20 hr) prior to slaughter to determine the effects on broiler yield parameters. MATERIALS AND METHODS
Eight trials involving 960 broilers with 120 birds per trial (60 males, 60 females) were conducted during the summer months. Day-old chicks secured from a commercial source were grown on a standard broiler ration to 52 to 58 days of age on the Louisiana State University Agricultural Center Poultry Research Farm. For each withdrawal period, feed and water were removed from pens and 20 birds of each sex were individually identified, weighed (farm weight), marked on the back with paint (color by period), and placed back into the original pens. The 20-, 15-, and 10-hr treatment groups were held in the pens for 14, 9, and 4 hr, respectively and weighed again (pen weight).
920
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
ABSTRACT Eight trials were conducted using broiler chickens between 52 to 58 days of age to study the effect of 10, 15, and 20 hr of feed and water withdrawal periods and five environmental holding shed treatments [open shed, air-conditioning (A/C), fanning and fogging (FF), fanning (F), and evaporative cooling (E/C)] on broiler yield parameters. Twelve birds of each sex were used for each withdrawal and shed combination making a total of 120 birds per trial. Live weight shrinkage increased with increasing length of withdrawal and male birds showed the highest weight loss. Dressed and chilled carcass weights, eviscerated yield, and chilled carcass yield based on farm weight decreased significantly with each increase in withdrawal period. The A/C, FF, F, and E/C sheds significantly reduced live shrinkage and improved broiler yields when compared with the open shed treatment. Preslaughter treatments did not influence carcass moisture uptake during chilling. (Key words: live shrinkage, yield, withdrawal time, holding shed)
921
WITHDRAWAL AND HOLDING EFFECTS ON YIELD
of birds to the environmental house to activate the dew cell elements. Dew cell element temperature (DC) was converted to dew point temperature (Tdp) and the temperature-humidity index (ThI) determined as given by Esmay (1969) with the following relationships: Tdp = -18.94607 + (.1803729 X DC) + (.00603709 X DC 2 ) - (.00002771 X DC 3 ) + (.0000004 X DC 4 )
[1]
ThI = .55 X Tdb + .02 X Tdp + 17.5
[2]
Birds were held in the environmental rooms for 6 hr and weighed again prior to slaughter (slaughter weight). Shed shrinkage was determined as the difference between pen weight and slaughter weight. The birds were then exsanguinated, scaled for 90 sec at 54 to 55 C, defeathered for 45 sec in an automatic feather picker, and carefully eviscerated, attempting to standardize cuts. Weights were taken for dressed carcass minus neck (carcass weight) prior to chilling and after chilling and 7 min of drip time (chilled carcass weight). A split-split plot arrangement of treatments in a randomized block design with trials as blocks, shed treatment being the main plot, feed and water withdrawal periods the splitplot, and sexes as the split-split plot was used for the study. Statistical analyses were carried out on data sexes separate and on a straight-run (SR) basis
TABLE 1. The effect of feed and water withdrawal periods on percent pen shrinkage and percent shed shrinkage Least square means period Pen
Shed shrin kage
Pen shrinkage Shed
1
Female
Male
SR
1.55 c
1.71 c
1.63c
3.96 b
4.02 b
3.99 b
5.23 a
5.66 a
5.45 a
.06
.08
.05
(hr)
Female
Male
SR1
1.87*
2.05 a
1.96 a
1.55 b
1.79 a
1.67 b
1.43 b
2.11 a
1.77 ab
.06
.15
.08
' (%)
4 6 9 6 14 6 SE
' ' Means in same column with different superscripts are significantly different (P<.01). 1
Straight-run birds.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
Four males and 4 females per withdrawal treatment were placed in coops and 2 males and 2 female filler birds added to maintain a 12-bird density before being transferred to the environmental treatment sheds. The five treatment sheds (rooms) were as follows: 1) an open shed (control), 2) an A/C room, 3) FF room, 4) F room, and 5) an E/C room. Each room was 22.52 m 3 (2.41 m long X 3.91 m wide X 2.39 m high) and completely sealed from an adjacent room with plywood and glass wool insulation. The open shed had three sides completely open and shared a common side with the A/C room, which was maintained at 19.4 C. The south side of the E/C room was covered with glass wool wick material (screen) with four F-80 fogging nozzles installed at 45°C angle above the screen and spraying 7.5 liter of the water per nozzle/hr at 22.5 kg pressure, continuously. The south sides of FF and the F rooms were open. A venturi type, 206 cfm fan was installed on the north side of both the FF and F sheds, blowing air over the birds, and the E/C room pulled (negative pressure) cool moist air across the birds. An F-80 fogging nozzle (as described) was installed 21 cm below but in front of the fan in the FF room. A Honeywell recorder connected in series to a Foxboro dew cell element (positioned at coop level) registered the dew cell element and dry bulb temperature (Tdb) in each room at intervals of 2 min between recordings. The A/C unit, foggers, fans, and Honeywell recorder were started 24 hr prior to arrival
922
BENIBO AND FARR TABLE 2. The effect of feed and water withdrawal periods on dressed carcass weight and chilled carcass weight Least square means
Withperiods
Chilled1 carcass weight
Dressed carcass weight Female
Male
SR1
1033 a 1013 b 1008 b
1263 a 1233 b 1215 c
1147 a 1122b llllc
(hr)
SE
SR1
1167 a 1151 b 1148 b
1387 a 1362 b 1343 c
1276 a 1257 b 1245 c
(g)
3
1
Male
3
5
2
4
5
' ' Means in same column with different superscripts are significantly different (P<.01). Straight-run birds.
with farm weight as a covariate, and applying least square regression as outlined in SAS by Helwig and Council (1979). Differences in treatments were separated by use of the PDIFF (Probability of Differences) option of the general linear models procedure.
feed in the digestive tract provided nutrients and energy at the beginning of withdrawal but with extended withdrawal body tissue was metabolized for these supplies, resulting in lower carcass weights and yields. Differences in
RESULTS AND DISCUSSION The percent pen shrinkage increased significantly with each increment in feed and water withdrawal period for male and SR birds (Table 1). These findings are consistent with those reported by Henry and Raunikar (1958), Snyder and Orr (1964), Wabeck (1972), and Salmon (1979). Withdrawal periods influenced percent shed shrinkage in female and SR birds but did not affect this parameter in male birds. Females receiving 10-hr withdrawal treatment had a higher percent shed shrinkage than did 15- and 20-hr treatment birds, which did not differ, suggesting that a higher rate of weight loss at early hours of withdrawal (attributable partly to emptying of digestive tract) was the influencing factor. Each increasing increment in withdrawal period resulted in lower dressed and chilled carcass weights and dry eviscerated and chilled carcass yield for male and SR birds (Tables 2 and 3). This agrees with the results of May and Brunson (1955), Brunson (1957), and Wabeck (1972), and the trend indicates significant edible losses in yield with prolonged withdrawal periods. The losses were a reflection of significant differences in live weights with time in these birds. Salmon (1979) has postulated that
TABLE 3. The effect of feed and water withdrawal periods on eviserated yield, chilled carcass yield, and percent moisture uptake With-
Least square means SR1
periods
Female
10 15 20 SE
63.99 a 62.79 b 62.54 b .16
10 15 20 SE
72.28 A 71.27 B 71.17 B .29
Chilled carcass yield 70.42 A 71.33 A 70.21 B 69.13 B 69.67 c 68.16c .27 .20
10 15 20 SE
12.95 A 13.59 A 13.82 A .38
Percent moisture uptal 9.90 A 11.42 B 12.08 A 10.54 A A 12.20 A 10.58 .25 .38
Male Dry eviscerated yield 64.07 a 62.53 b 61.64 c .16
64.02 a 62.65 b 62.10 c .12
a,b,c Means in same column with different superscripts are different (P<.01). A,B,CMeans in same column with different superscripts are different (P<.05). 1 Straight-run birds.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
10 15 20
Female
WITHDRAWAL AND HOLDING EFFECTS ON YIELD
923
TABLE 4. Means and ranges for dry bulb temperatures, dew point temperatures, and temperature-humidity indexes (ThI) in the holding shed
Holding shed
Mean dry b u l b temperature
range
Open A/C2 FF3-4 Fan E/C5
28.6 19.4 22.8 25.9 24.2
2 6 . 1 - -30.6 1 8 . 9 - -20.6 2 2 . 2 --24.4 2 3 . 9 --27.8 2 2 . 8 - -25.6
Temperaturehumidity index1
Mean dew p o i n t temperature
Rangi
Mean
Range
23.2 12.9 20.5 21.7 22.2
2 2 . 2 --25.0 1 1 . 1 --13.9 1 8 . 3 --22.2 1 9 . 4 --22.8 2 0 . 5 - -23.3
78.2 65.2 71.7 74.9 73.5
7 6 --81 6 4 --68 7 0 --73 7 3 --77 7 2 --75
(.c;
ThI = .55 X (dry bulb temperature) + .2 X (dew point temperature) + 17.5. Air-conditioned.
3
Fan and fogger.
4
Values for only three trials.
5
Evaporatively cooled.
carcass weights and yield did not occur for females in the 15- and 20-hr treatment groups, because live weight losses stabilized for these birds in the same periods. The withdrawal treatments did not influence moisture uptake in the chiller for the male and female birds, which agrees with findings of Salmon (1979) and Brunson (1957). Females absorbed more moisture expressed on absolute or percentage basis than did males (Table 3). However, when the sexes were pooled in analysis as SR, a greater uptake of moisture was found for the 15- and 20-hr withdrawal treatments. Prevalent environmental conditions in the holding sheds are presented in Table 4. Only three trials were used in the FF shed treatment due to a dew cell recorder malfunction. Mean Tdb and Tdp were consistently higher in the open shed with resultant higher ThI during all trials. It may be noted that ThI is an indication of level of discomfort and an empirically determined index weighting Tdb and Tdp for comparison with animal performance. Correlation coefficients of Tdb and Tdp and ThI with percent shed shrinkage were .6985, .4900, and .6955, respectively. Thus, one may attribute part of the higher live shrinkage to holding temperature (through dehydration) in the open shed as suggested by Marion et al. (1970). Heat moderation by A/C and FF were superior to F and E/C for females but not different for males (Table 5).
TABLE 5. The effect of environmental holding shed on percent shed shrinkage, dressed carcass weight, and chilled carcass weight Environmental holding shed
Female
Open A/C2 FF3 Fan E/C4 SE
2.59a 1.19 c 1.26 c 1.55b 1.48b .07
Open A/C FF Fan E/C SE
1005b 1022a 1026a 1018a 1019a 3
Open A/C FF Fan E/C SE
B
Least square m e a n Male
SR 1
Percent shed shrinkage 3.61a 1.35b 1.40 b 1.86b 1.71b .20
3.10a 1.28d 1.33cd 1.70b 1.60bc .11
Dressed carcass w eight (g) 1215b 1245a 1241a 1243a 1238a 4
HOOb 1133a 1132a 1131a 1128a 3
Chilled carcass weight (g) 1344B 1373A 1369A 1373A 1362A 7
1136 1166A 1158A 1158A 1159A 7
1240B 1268A 1263A 1265A 1260A 5
' ' ' Means in same column with different superscripts are different (P<.01). AB ' Means in same column with different superscripts are different (P<.05). 1
Straight-run birds.
3
2
Air-conditioned.
' Evaporatively cooled.
Fan and fogger.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
1 2
924
BENIBO AND FARR
TABLE 6. The effect of environmental holding shed on yield, chilled carcass yield, and moisture uptake Environmental holding shed
Female
Least square means Male SR1 Dry eviscerated yieldI
b
62.29 63.35 a 63.52 a 63.13 a 63.17 a .28
Open A/C FF Fan E/C SE
70.42 A 72.25 A 71.73 A 71.74 A 71.73 A .37
Open A/C FF Fan E/C SE
13.10 A 14.04 A 12.93 A 13.64 A 13.53 A .49
61.68b 63.17a 62.99 a 63.09 a 62.80 a .21
62.00 b 63.25 a 63.25 a 63.12 a 62.99a .15
Chilled carcass yield 68.19 B 69.64 A 69.50 A 69.64 A 69.17 A .35
REFERENCES 69.33 B 70.94 A 70.60 A 70.7O A 70.46 A .26
ercent moisture uptalKe 10.59 A 10.28 A 10.38 A 10.38 A 10.13 A .42
———
11.86 A 12.16 A 11.62 A 12.02 A 11.84^ .32
' Means in same column with different superscripts are different (P<.01). AB ' Means in same column with different superscripts are different (P<.05). 1
Straight-run birds.
2
Air-conditioned.
3
Fan and fogger.
4
Evaporatively cooled.
Dressed carcass weights, dry yield, and chilled carcass yield based o n farm weight were significantly lower in t h e open shed than in t h e
Branson, C. C , 1957. Effect of length of fasting period with subsequent ice-chilling on eviscerated yield and moisture content of broiler carcasses. Poultry Sci. 36:1107. (Abstr.) Esmay, M. L., 1969. Page 101 in Principles of Animal Environment. Avi Publ. Co., Inc. Helwig, J. T., and K. A. Council, 1979. Statistical Analyses System Users' Guide. SAS Inst. Inc., Raleigh, NC. Henry, W. R., and R. Raunikar, 1958. Weight losses of broilers during the live haul. North Carolina Agric. Econ. Inf. Ser. No. 69. Marion, W. W., R. A. Jungk, and S. T. Maxon, 1970. Influence of handling and processing on weights and yields of turkey meat. Food Technol. 24: 924-926. May, K. N., and C. C. Brunson, 1955. Effect of starvation period on eviscerated yields of broilers. Poultry Sci. 34:1210. Salmon, R. E., 1979. Effect of food and water deprivation on live weight shrinkage, eviscerated carcass yield and water absorption during chilling of turkey carcasses. Br. Poult. Sci. 20:303-306. Snyder, E. S., and H. L. Orr, 1964. Pages 4 3 - 4 8 in Poultry meat: processing, quality factors, yields. Ont. Dept. Agric. Publ. 9. Thomson, J. E., A. W. Kotula, and J. A. Kinner, 1961. The effect of temperature and time of prechill on total moisture absorption by fryer chickens. Poultry Sci. 40:1139-1142. Wabeck, C. J., 1972. Feed and water withdrawal time relationship to processing yield and potential fecal contamination of broilers. Poultry Sci. 51: 1119-1121.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on February 27, 2015
Open A/C 2 FF 3 Fan E/C4 SE
A/C, F F , F , and E/C r o o m s and these were n o t different from o n e a n o t h e r (Tables 5 and 6). Again, this was reflected b y higher holding t e m p e r a t u r e and p e r c e n t live shrinkage for birds held in t h e o p e n shed. Thus, decreasing t h e ThI during t h e holding period m a y be a key t o improving broiler yield and reducing live b o d y skrinkage. Holding shed t r e a t m e n t did n o t influence moisture u p t a k e during chilling; however, in each shed females absorbed m o r e m o i s t u r e t h a n males on b o t h an absolute and a percentage basis.