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Feed and Water Withdrawal Time Relationship to Processing Yield and Potential Fecal Contamination of Broilers1
Feed and Water Withdrawal Time Relationship to Processing Yield and Potential Fecal Contamination of Broilers1 C. J .
WABECK2
Poultry Science Department, University of Maryland, College Park, Maryland 20742 (Received for publication September 17, 1971) ABSTRACT Trials were conducted to determine feed and water withdrawal times for broilers prior to slaughter which would result in lowest loss in eviscerated yield and lessen potential for fecal contamination of carcasses. Percent loss in live weight expressed as shrink showed a linear relationship with time. Loss at the twenty-four hour period was approximately double that at the twelfth hour. Eviscerated yield when based on initial weight showed a tendency for loss in yield with increasing withdrawal time whereas the opposite trend was shown when yield was based on weight at time of slaughter. Least differences were noted from the eighth to tenth hour of holding. Fecal contents were lowest at the eighth to tenth hour of withdrawal. This would be conducive to a lessened possibility for fecal contamination. The data points out the need for more precise scheduling of withdrawal and holding period prior to slaughter to reduce losses due to yields and fecal contamination of carcasses. POULTRY SCIENCE 51: 1119-1121, 1972
INTRODUCTION
N AREA of practical interest to pro- cessing personnel has been length of withdrawal as it ultimately affects fecal contamination. Fecal contamination can be caused by other factors but of primary importance is the amount of and condition of feces at the time of slaughter and the relationship to withdrawal time. Current practice is to remove feed from the birds four hours prior to pickup by the catching crew. It is felt that this allows sufficient time between feed withdrawal and slaughter for most of the feces to be voided. May and Brunson (1955) found that broilers starved for 24 hours yielded significantly lower eviscerated weights than for groups held for 0, 3, 6, and 12 hours prior to slaughter. Henry and Raunikar (1958) and Snyder and Orr (1964) found that as time from feed withdrawal to slaughter in-
A
1
Scientific Article No. A 1720. Contribution No. 4486 of the Maryland Agricultural Experiment Station, Department of Poultry Science. 2 Broiler Substation, Box 285, Quantico Rd., Salisbury, Md. 21801.
creased there was an increased rate of shrink for live weight with a decreasing percentage eviscerated yield. Feed withdrawal time as it affects potential fecal contamination and yields were studied in three separate trials. EXPERIMENTAL PROCEDURE
Male broilers were removed from the pens, placed in coops, and held without feed or water for the time parameters set for each trial. The birds were weighed immediately after removal to obtain the initial weights. In the first trial, thirty birds per time period were weighed prior to slaughter but eviscerated yield was not determined. Eviscerated yield in Trials 2 and 3 were established and related to time of removal as well as eviscerated yield based on the weight of the birds prior to slaughter. Forty and thirty birds per withdrawal period were held in Trials 2 and 3 respectively. Exsanguination was accomplished by external carotid severance followed by a ninety second bleed time. Birds were placed in an Ashley Sure Scald scalder (Ashley Machine, Inc., Greensburg, Indiana) for
1119
1120
C. J. WABECK
TAELK 1.—Average percent shrink for birds drawn from feed and water for various time periods prior to slaughter
small sample size but the regression value demonstrates the increased loss over time. Birds left without feed and water for Trial 1 Trial 2 Trial 3 Time (hrs.) twenty-four hours showed a marked loss in weight over birds held only twelve hours. 0 1.83 2.59 1.29 4 In commercial operation birds are some6 3.89 — — times held in coops overnight. 8 3.61 1.93 2.57 10 5.34 1.67 — Percent eviscerated yield, minus giblets 12 5.67 2.22 2.67 and necks, are shown in Table 2 with the 14 6.53 — — 24 5.89 4.93 4.00 regression and variance analyses for Trials b1 .1647 .1986 .1093 2 and 3. Yield was not recorded in the iniSignificance N.S. P<.01 P<.05 tial trial. In Trial 2, yield based on initial 1 Regression coefficient where x = time and y = %. weight declined as time of withdrawal increased whereas the opposite trend was ninety seconds at S2°C. and defeathered found for the third trial. The negative refor 55 seconds in a Spin-Pik Machine (The gression line in the second trial was highly Pickwick Company, Cedar Rapids, Iowa). significant at the P < .01 level whereas the Viscera were removed carefully through ab- results for Trial 3 were inconclusive. Bedominal entry and eviscerated weight was cause of the significance, in Trial 2 based obtained on the hot carcasses minus giz- on initial weights at time of withdrawal, zards, livers, hearts, and necks. eviscerated yields will decline as withIn Trials 2 and 3, the amount of feces drawal time increases which agrees with the was subjectively scored for amount in the findings of Henry and Raunikar (1958) intestinal tract from cecum to cloaca. The and Snyder and Orr (1964). Yield values scores are as follows: l=none, 2 = small based on the initial weight at cooping reamount, 3 = medium amount, and 4 = large flect shrink in the carcass weight therefore amount. In Trial 1, the amount present a significant negative slope indicates a sigwas noted but not scored. Amount was de- nificance in loss in weight of carcass over termined by cutting the viscera from the time. Yields based on weights at time of cecum to cloaca. The condition of the feces slaughter contain losses due to shrinkage in was also noted for each time period to arrive both the numerator and denominator. A posat a statement of general condition which itive regression would indicate a slower rate could be attributed to broilers being off feed and water for different intervals. TABLE 2.—Eviscerated yield {percent) for bitds withStatistical analyses of the least squares drawn from feed and water for various time periods prior to slaughter regression coefficient were carried out by computer according to the method of Li Initial Weight 1 Slaughter Weight 2 Time (hrs.) (1964). RESULTS AND DISCUSSION The average percent shrink, regression coefficient, and analyses of variance for linear regression are presented in Table 1. Loss in weight as shown by the data is linear with time withdrawal. The non-significant results in the first trial was due to
0 4 6 8 10 12 14 24 3 b Significance 1 2
Trial 2
Trial 3
66.28 64.02 63.96 61.31 -.02380 P<.01
Trial 2
Trial 3
63.89
65.74
64.60
65.04 65.89 64.05
65.90 — 66.14
66 30 66.60 65.80
65.11 .0038 N.S.
66.04 .0011 N.S.
.
Based on initial weight. Based on weight after holding. • Regression coefficient where x=time and y=%.
_
67.80 .0046 P<0.5
1121
BROILER PROCESSING
of shrinkage in the eviscerated carcass relative to the rate of shrinkage in total bird weight at slaughter. Based on weights at time of slaughter, Trial 3 results show a greater rate of loss in slaughter weight than in the eviscerated carcass while Trial 2 results were non-significant. Yields therefore are a function of not only withdrawal time but also of when the birds are weighed. If birds are weighed just after pickup eviscerated yield will be less than if yields are calculated from weighing just prior to slaughter. Data for visual observations of intestinal contents are presented in Table 3 and are based on Trials 2 and 3 in which the scoring system was used to relate to amount of feces present. Comments recorded in Trial 1 followed the same trend as the scoring in succeeding trials. There was a bird to bird variation in fecal contents for each withdrawal period, but on an overall basis, it appeared that the eight to ten hour period resulted in the least amount of feces. The non-significance of the regression analyses showed that the results were not linear in nature. In essence, the results show a quadratic effect where the amount decreases to the eighth hour, when there is a leveling off, and a large increase in contents from the twelfth to the twenty-fourth hour. The reTABLE 3.—Average visual scores for fecal contents1 in the intestine for birds withdrawn from feed and water for various time periods prior to slaughter. Time (hrs.) 0 4 6 8 10 12 14 24 b2 Significance
Trial 2
Trial 3
_
_
2.03
2.57
1.40
1.67 1.57 1.80
—
1.65
—
1.80 -.0009 N. S.
—
2.00 -.0011 N. S.
1
l = None, 4=large amount. Regression coefficient where y=average score. 2
x=time
and
suits demonstrate that the eighth to the tenth hour of total withdrawal time prior to slaughter results in the least amount of fecal contents. An analysis of the condition of the feces in each trial was noted. Again a bird to bird variation within time treatments existed but there was a predominant condition for each period. In general, the feces were moist rather than firm throughout each time period in each trial. There was a tendency for feces to become firmer around the eight to ten hour period with an increased amount of moisture around the twelfth hour. When birds were held for twenty-four hours there was an extreme watery condition noted for all birds. The trials indicate that broilers should be off feed and water for eight to ten hours prior to slaughter to reduce fecal contamination. At this time, the amount of fecal material in the intestine would be minimal. From the data collected, it appears that there may be a relationship between shrink and dressing percentages. It is important that scheduling of withdrawal prior to pickup, and holding, be the period of eight to ten hours which may cause the least fecal problems. Further studies are scheduled on feed withdrawal periods, and other factors which may have an influence on fecal contamination problems in the processing plant. REFERENCES Henry, W. R., and R. Raunikar, 1958. Weight losses of broilers during the live haul. North Carolina Agr. Econ. Information Series No. 69. Li, C. C , 1964. Introduction to Experimental Statistics. 1st ed. McGraw-Hill Book Company, New York, N.Y. May, K. N., and C. C. Branson, 1955. Effect of starvation period on eviscerated yield of broilers. Poultry Sci. 34: 1210. Snyder, E. S., and H. L. Orr, 1964. Poultry meat: processing, quality factors, yields. Ontario Department of Agriculture Publication 9, pp. 4 3 48.
WABECK2
Poultry Science Department, University of Maryland, College Park, Maryland 20742 (Received for publication September 17, 1971) ABSTRACT Trials were conducted to determine feed and water withdrawal times for broilers prior to slaughter which would result in lowest loss in eviscerated yield and lessen potential for fecal contamination of carcasses. Percent loss in live weight expressed as shrink showed a linear relationship with time. Loss at the twenty-four hour period was approximately double that at the twelfth hour. Eviscerated yield when based on initial weight showed a tendency for loss in yield with increasing withdrawal time whereas the opposite trend was shown when yield was based on weight at time of slaughter. Least differences were noted from the eighth to tenth hour of holding. Fecal contents were lowest at the eighth to tenth hour of withdrawal. This would be conducive to a lessened possibility for fecal contamination. The data points out the need for more precise scheduling of withdrawal and holding period prior to slaughter to reduce losses due to yields and fecal contamination of carcasses. POULTRY SCIENCE 51: 1119-1121, 1972
INTRODUCTION
N AREA of practical interest to pro- cessing personnel has been length of withdrawal as it ultimately affects fecal contamination. Fecal contamination can be caused by other factors but of primary importance is the amount of and condition of feces at the time of slaughter and the relationship to withdrawal time. Current practice is to remove feed from the birds four hours prior to pickup by the catching crew. It is felt that this allows sufficient time between feed withdrawal and slaughter for most of the feces to be voided. May and Brunson (1955) found that broilers starved for 24 hours yielded significantly lower eviscerated weights than for groups held for 0, 3, 6, and 12 hours prior to slaughter. Henry and Raunikar (1958) and Snyder and Orr (1964) found that as time from feed withdrawal to slaughter in-
A
1
Scientific Article No. A 1720. Contribution No. 4486 of the Maryland Agricultural Experiment Station, Department of Poultry Science. 2 Broiler Substation, Box 285, Quantico Rd., Salisbury, Md. 21801.
creased there was an increased rate of shrink for live weight with a decreasing percentage eviscerated yield. Feed withdrawal time as it affects potential fecal contamination and yields were studied in three separate trials. EXPERIMENTAL PROCEDURE
Male broilers were removed from the pens, placed in coops, and held without feed or water for the time parameters set for each trial. The birds were weighed immediately after removal to obtain the initial weights. In the first trial, thirty birds per time period were weighed prior to slaughter but eviscerated yield was not determined. Eviscerated yield in Trials 2 and 3 were established and related to time of removal as well as eviscerated yield based on the weight of the birds prior to slaughter. Forty and thirty birds per withdrawal period were held in Trials 2 and 3 respectively. Exsanguination was accomplished by external carotid severance followed by a ninety second bleed time. Birds were placed in an Ashley Sure Scald scalder (Ashley Machine, Inc., Greensburg, Indiana) for
1119
1120
C. J. WABECK
TAELK 1.—Average percent shrink for birds drawn from feed and water for various time periods prior to slaughter
small sample size but the regression value demonstrates the increased loss over time. Birds left without feed and water for Trial 1 Trial 2 Trial 3 Time (hrs.) twenty-four hours showed a marked loss in weight over birds held only twelve hours. 0 1.83 2.59 1.29 4 In commercial operation birds are some6 3.89 — — times held in coops overnight. 8 3.61 1.93 2.57 10 5.34 1.67 — Percent eviscerated yield, minus giblets 12 5.67 2.22 2.67 and necks, are shown in Table 2 with the 14 6.53 — — 24 5.89 4.93 4.00 regression and variance analyses for Trials b1 .1647 .1986 .1093 2 and 3. Yield was not recorded in the iniSignificance N.S. P<.01 P<.05 tial trial. In Trial 2, yield based on initial 1 Regression coefficient where x = time and y = %. weight declined as time of withdrawal increased whereas the opposite trend was ninety seconds at S2°C. and defeathered found for the third trial. The negative refor 55 seconds in a Spin-Pik Machine (The gression line in the second trial was highly Pickwick Company, Cedar Rapids, Iowa). significant at the P < .01 level whereas the Viscera were removed carefully through ab- results for Trial 3 were inconclusive. Bedominal entry and eviscerated weight was cause of the significance, in Trial 2 based obtained on the hot carcasses minus giz- on initial weights at time of withdrawal, zards, livers, hearts, and necks. eviscerated yields will decline as withIn Trials 2 and 3, the amount of feces drawal time increases which agrees with the was subjectively scored for amount in the findings of Henry and Raunikar (1958) intestinal tract from cecum to cloaca. The and Snyder and Orr (1964). Yield values scores are as follows: l=none, 2 = small based on the initial weight at cooping reamount, 3 = medium amount, and 4 = large flect shrink in the carcass weight therefore amount. In Trial 1, the amount present a significant negative slope indicates a sigwas noted but not scored. Amount was de- nificance in loss in weight of carcass over termined by cutting the viscera from the time. Yields based on weights at time of cecum to cloaca. The condition of the feces slaughter contain losses due to shrinkage in was also noted for each time period to arrive both the numerator and denominator. A posat a statement of general condition which itive regression would indicate a slower rate could be attributed to broilers being off feed and water for different intervals. TABLE 2.—Eviscerated yield {percent) for bitds withStatistical analyses of the least squares drawn from feed and water for various time periods prior to slaughter regression coefficient were carried out by computer according to the method of Li Initial Weight 1 Slaughter Weight 2 Time (hrs.) (1964). RESULTS AND DISCUSSION The average percent shrink, regression coefficient, and analyses of variance for linear regression are presented in Table 1. Loss in weight as shown by the data is linear with time withdrawal. The non-significant results in the first trial was due to
0 4 6 8 10 12 14 24 3 b Significance 1 2
Trial 2
Trial 3
66.28 64.02 63.96 61.31 -.02380 P<.01
Trial 2
Trial 3
63.89
65.74
64.60
65.04 65.89 64.05
65.90 — 66.14
66 30 66.60 65.80
65.11 .0038 N.S.
66.04 .0011 N.S.
.
Based on initial weight. Based on weight after holding. • Regression coefficient where x=time and y=%.
_
67.80 .0046 P<0.5
1121
BROILER PROCESSING
of shrinkage in the eviscerated carcass relative to the rate of shrinkage in total bird weight at slaughter. Based on weights at time of slaughter, Trial 3 results show a greater rate of loss in slaughter weight than in the eviscerated carcass while Trial 2 results were non-significant. Yields therefore are a function of not only withdrawal time but also of when the birds are weighed. If birds are weighed just after pickup eviscerated yield will be less than if yields are calculated from weighing just prior to slaughter. Data for visual observations of intestinal contents are presented in Table 3 and are based on Trials 2 and 3 in which the scoring system was used to relate to amount of feces present. Comments recorded in Trial 1 followed the same trend as the scoring in succeeding trials. There was a bird to bird variation in fecal contents for each withdrawal period, but on an overall basis, it appeared that the eight to ten hour period resulted in the least amount of feces. The non-significance of the regression analyses showed that the results were not linear in nature. In essence, the results show a quadratic effect where the amount decreases to the eighth hour, when there is a leveling off, and a large increase in contents from the twelfth to the twenty-fourth hour. The reTABLE 3.—Average visual scores for fecal contents1 in the intestine for birds withdrawn from feed and water for various time periods prior to slaughter. Time (hrs.) 0 4 6 8 10 12 14 24 b2 Significance
Trial 2
Trial 3
_
_
2.03
2.57
1.40
1.67 1.57 1.80
—
1.65
—
1.80 -.0009 N. S.
—
2.00 -.0011 N. S.
1
l = None, 4=large amount. Regression coefficient where y=average score. 2
x=time
and
suits demonstrate that the eighth to the tenth hour of total withdrawal time prior to slaughter results in the least amount of fecal contents. An analysis of the condition of the feces in each trial was noted. Again a bird to bird variation within time treatments existed but there was a predominant condition for each period. In general, the feces were moist rather than firm throughout each time period in each trial. There was a tendency for feces to become firmer around the eight to ten hour period with an increased amount of moisture around the twelfth hour. When birds were held for twenty-four hours there was an extreme watery condition noted for all birds. The trials indicate that broilers should be off feed and water for eight to ten hours prior to slaughter to reduce fecal contamination. At this time, the amount of fecal material in the intestine would be minimal. From the data collected, it appears that there may be a relationship between shrink and dressing percentages. It is important that scheduling of withdrawal prior to pickup, and holding, be the period of eight to ten hours which may cause the least fecal problems. Further studies are scheduled on feed withdrawal periods, and other factors which may have an influence on fecal contamination problems in the processing plant. REFERENCES Henry, W. R., and R. Raunikar, 1958. Weight losses of broilers during the live haul. North Carolina Agr. Econ. Information Series No. 69. Li, C. C , 1964. Introduction to Experimental Statistics. 1st ed. McGraw-Hill Book Company, New York, N.Y. May, K. N., and C. C. Branson, 1955. Effect of starvation period on eviscerated yield of broilers. Poultry Sci. 34: 1210. Snyder, E. S., and H. L. Orr, 1964. Poultry meat: processing, quality factors, yields. Ontario Department of Agriculture Publication 9, pp. 4 3 48.