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Some Factors Influencing Feed Wastage
1665
RESEARCH NOTES
was determined by the chi-square test, using hen-days and eggs. Table 1 shows hen-day production as percentage for convenient comparison and to allow differences to be expressed in a uniform manner. In 1965 there was no significant difference between lines, but in all other years differences between lines were very highly significant (P < 0.001). In three of the years the low oxygen line had higher production, but in the remaining 8 years the high oxygen line had the higher rate. Hatchability of fertile eggs is shown in Table 1. In all generations the high oxygen line hatched at a higher rate than the low. In every year except 1967 the
difference was significant. In 1963, 1968, 1969 and 1970 the differences were very highly significant (P < 0.001). Intra-generation comparisons of egg weight and fertility failed to show any consistent significant trends. ACKNOWLEDGMENT
This investigation was started under Southern Regional Poultry Breeding Project No. S-41. Foundation stock was supplied by the Southern Regional Poultry Genetics Laboratory, Athens, Georgia. REFERENCE MacLaury, D. W. and T. H. Johnson, 1972. Selection for high and low oxygen consumption in chickens. Poultry Sci. 51: 591-597.
SOME FACTORS INFLUENCING FEED WASTAGE J. F. HURNIK, J. D. SUMMERS AND W. D. MORRISON Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario NIG 2W1, Canada (Received foi publication February 7, 1973) ABSTRACT Two strains of commercial-type layers and two different diets were used in this study. During two observation periods, from 8 to 12 weeks in community cages and from 18-21 weeks in individual cages, weekly feed wastage was recorded. The amount of wasted feed during the first period was more dependent on the strain of bird than on the diet, similarly the regression coefficients of feed wastage on the distance of feeding space to waterers were affected more by strains than by diets. Feed wastage, of individually caged birds, was less affected by strains than that for the community cages. The overall level of feed wastage by younger birds in community cages was higher (3.6%) than that for the older, individually caged pullets (1.6%). POULTRY SCIENCE 52: 1665-1667,1973
INTRODUCTION
Feed wastage associated with consumatory activities of chickens could represent a substantial economic loss in poultry production. Among important factors which have a prime impact on this trait are such individual behavioral characteristics as emotionality, playfulness, curiosity and natural or learned preferences for taste, form and/or color of feed. The expression of all these characteristics depends on the feeding systems applied and on the stimulation associated with the
environmental conditions of the pen. Feed wastage can vary with the total feed and water intake (Weiss and Borbely, 1960), and can be effectively lowered by proper debeaking (Bauermann, 1959). It is also known that feed wastage depends on the sex and on the level of feed in the trough (Reece et al., 1971). Nevertheless, it can be concluded that genetical dispositions and possible interactions with environmental arrangements may play a role in this kind of feed wastage. Additionally, it might also be assumed that for subop-
1666
RESEARCH NOTES
timal feeding systems, selection for decreased feed wastage could be economically more feasible than selection for traditional production traits where genetic variability has been markedly reduced by intensive breeding programs. MATERIALS AND METHODS Subjects: Debeaked female chickens from two commercial layer strains were used in this study. Experimental Procedure: At three weeks of age 192 birds of each strain were randomly allocated into 32 community cages consisting of eight rows of four cages. Each row with 12 chickens per cage (75 X 40 X 40 cm.), contained four possible combinations of two strains and two diets. The diets differed in feed components, the levels of protein and metabolizable energy (M.E.) content. Diet CS, a chicken starter ration, contained 20% protein, 2920 Kcal. of M.E./kg.; Diet BS, a broiler starter, contained 23% protein and 2980 Kcal. of M.E./kg. The period of observation started at the age of eight weeks and was continued until the twelfth week of age. During this time, the measured dependent variable was a weekly record of feed wastage for each group of 12 birds. This was accomplished by the placement of aluminium dishes under the feeders. Both corners of each cage contained a cup-type waterer. To calculate the possible effect of the distance from the waterers on feed wastage, the collection area for each community cage was divided into five equal parts, each part consisting of 15 cm. in length. At 12 weeks of age 100 birds from each strain were transferred into individual cages (20 X 40 X 40 cm.) arranged in five two-tier rows containing 20 cages in each tier and row combination. Henceforth, the birds were fed a pullet grower
diet (PG) containing 14% protein and 2760 Kcal. of M.E./kg. and broiler finisher (BF) containing 20% protein and 3090 Kcal. of M.E./kg. At 18 weeks of age individual weekly feed wastage was recorded. This period of observation was carried out for three weeks. Feed and water were available ad libitum during both periods. The quantity of feed in the trough-type of feeder was kept between the level of § to § of the capacity of the feeder. Statistics: Analysis of variance and the F-test were applied to dependent variables in both periods. The null hypotheses were rejected at the significancy level a = .05, but for additional information all sources were stated for a < .10. RESULTS AND DISCUSSION During the first period separate analysis of variance for each single week confirmed that feed wastage was more affected by the genotype (strains) than by the composition of the diets. One of the strains consistently wasted more feed during all four weeks. Except for one week all the differences were significant (P < .05). The effect of diets did not produce significant differences in any of the four weeks of this period, but the overall feed wastage was lower for the broiler starter diet (Table 1). The interactions between diets and strains were not significant. Positional effect of the eight cage rows TABLE 1.—Average weekly feed wastage (8-12 weeks of age) per community cage of 12 birds Strain
Feed wastage (grams)
Diet
A
B
BS
CS
160
112
132
140
Note: BS = Broiler Starter CS = Chicken Starter
1667
RESEARCH NOTES
in the pen indicated highest feed wastage in the rows closest to the doors and side walls with less wastage in the center rows (P < .10). In the crosswise arrangement (four cages), feed wastage increased towards the working area, but this trend was even less pronounced than the effect of rows. Within a cage, feed wastage varied with the distance from the waterer. Linear regression on the length from the sides to the center of the feeder indicates a highest feed wastage at the center of the feeder. The differences in regression coefficients on the distance to the waterers were influenced more by strains (P < .10) than by the diets (P > .10). Assuming that the frequency of feeding was the same across the length of the feeder (which may have not been true in each cage), this fact could mean that the feeding responses in the central part were perhaps associated with a higher degree of selectiveness in respect to crumbles and/or with more "playing" with the feed. Another explanation could be that the subordinate and more frustrated birds were barred from the generally preferred feeding areas of the shortest distance to waterers. During the second observation period concerned with the individual variability in weekly feed wastage, the differences between the strains were nonsignificant. However, there was a trend for continuously higher wastage in the same strain as noted in the first period (Tables 1 and 2). Differences in feed wastage between diets were significant (P < .05) in one of the three weekly observations. Similarly to first period, birds fed the higher M.E. diet (broiler finisher) showed lower feed wastage. Cage tier levels, as an additional factor compared to previous period, did not significantly affect the amount of feed wasted. Nevertheless,
TABLE 2.—Average weekly feed wastage (18-21) weeks of age) for individual bird per cage Strain
Feed wastage (grams)
Diet
A
B
BF
PG
8.3
6.5
5.8
8.9
Tier Level Upper Lower 7.0
7.8
Note: BF = Broiler Finisher PG = Pullet Grower
higher wastage was observed in the lower tier level. Considering positional effect of the five cage rows in the pen, the highest feed wastage occurred in the row closest to the permanently operating exhaust fan. The contrast in feed wastage between this row and all four residual rows was significant (P < .05). Lowest wastage was observed in the center row. The total wastage per cage row within the pen appeared to have no relation to the allocation of light bulbs. The overall percentage of feed wasted was higher by younger birds in community cages (3.6%) than by individually allocated older birds (1.6%) in the second period. Further studies are considered to utilize the relatively large proportion of intrastrain variability associated with this trait. In present form the results suggest the possibility of decreasing feed wastage by more attention to those stimuli (primarily visual and audial) which in any way disturb the birds and cause fear or frustration.
REFERENCES Bauermann, J. F., 1959. An investigation of the effect of debeaking on feed wastage and fertility of Single Comb White Leghorns. Poultry Sci. 38: 1189. Reece, F. N., J. W. Deaton, J. D. May and K. N. May, 1971. Cage versus floor rearing of broiler chickens. Poultry Sci. 50: 1786-1790. Weiss, H. S., and E. Borbely, 1960. An evaluation of feed lost in the drinking water: Comparison among management systems and individual birds. Poultry Sci. 39: 1159-1166.
RESEARCH NOTES
was determined by the chi-square test, using hen-days and eggs. Table 1 shows hen-day production as percentage for convenient comparison and to allow differences to be expressed in a uniform manner. In 1965 there was no significant difference between lines, but in all other years differences between lines were very highly significant (P < 0.001). In three of the years the low oxygen line had higher production, but in the remaining 8 years the high oxygen line had the higher rate. Hatchability of fertile eggs is shown in Table 1. In all generations the high oxygen line hatched at a higher rate than the low. In every year except 1967 the
difference was significant. In 1963, 1968, 1969 and 1970 the differences were very highly significant (P < 0.001). Intra-generation comparisons of egg weight and fertility failed to show any consistent significant trends. ACKNOWLEDGMENT
This investigation was started under Southern Regional Poultry Breeding Project No. S-41. Foundation stock was supplied by the Southern Regional Poultry Genetics Laboratory, Athens, Georgia. REFERENCE MacLaury, D. W. and T. H. Johnson, 1972. Selection for high and low oxygen consumption in chickens. Poultry Sci. 51: 591-597.
SOME FACTORS INFLUENCING FEED WASTAGE J. F. HURNIK, J. D. SUMMERS AND W. D. MORRISON Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario NIG 2W1, Canada (Received foi publication February 7, 1973) ABSTRACT Two strains of commercial-type layers and two different diets were used in this study. During two observation periods, from 8 to 12 weeks in community cages and from 18-21 weeks in individual cages, weekly feed wastage was recorded. The amount of wasted feed during the first period was more dependent on the strain of bird than on the diet, similarly the regression coefficients of feed wastage on the distance of feeding space to waterers were affected more by strains than by diets. Feed wastage, of individually caged birds, was less affected by strains than that for the community cages. The overall level of feed wastage by younger birds in community cages was higher (3.6%) than that for the older, individually caged pullets (1.6%). POULTRY SCIENCE 52: 1665-1667,1973
INTRODUCTION
Feed wastage associated with consumatory activities of chickens could represent a substantial economic loss in poultry production. Among important factors which have a prime impact on this trait are such individual behavioral characteristics as emotionality, playfulness, curiosity and natural or learned preferences for taste, form and/or color of feed. The expression of all these characteristics depends on the feeding systems applied and on the stimulation associated with the
environmental conditions of the pen. Feed wastage can vary with the total feed and water intake (Weiss and Borbely, 1960), and can be effectively lowered by proper debeaking (Bauermann, 1959). It is also known that feed wastage depends on the sex and on the level of feed in the trough (Reece et al., 1971). Nevertheless, it can be concluded that genetical dispositions and possible interactions with environmental arrangements may play a role in this kind of feed wastage. Additionally, it might also be assumed that for subop-
1666
RESEARCH NOTES
timal feeding systems, selection for decreased feed wastage could be economically more feasible than selection for traditional production traits where genetic variability has been markedly reduced by intensive breeding programs. MATERIALS AND METHODS Subjects: Debeaked female chickens from two commercial layer strains were used in this study. Experimental Procedure: At three weeks of age 192 birds of each strain were randomly allocated into 32 community cages consisting of eight rows of four cages. Each row with 12 chickens per cage (75 X 40 X 40 cm.), contained four possible combinations of two strains and two diets. The diets differed in feed components, the levels of protein and metabolizable energy (M.E.) content. Diet CS, a chicken starter ration, contained 20% protein, 2920 Kcal. of M.E./kg.; Diet BS, a broiler starter, contained 23% protein and 2980 Kcal. of M.E./kg. The period of observation started at the age of eight weeks and was continued until the twelfth week of age. During this time, the measured dependent variable was a weekly record of feed wastage for each group of 12 birds. This was accomplished by the placement of aluminium dishes under the feeders. Both corners of each cage contained a cup-type waterer. To calculate the possible effect of the distance from the waterers on feed wastage, the collection area for each community cage was divided into five equal parts, each part consisting of 15 cm. in length. At 12 weeks of age 100 birds from each strain were transferred into individual cages (20 X 40 X 40 cm.) arranged in five two-tier rows containing 20 cages in each tier and row combination. Henceforth, the birds were fed a pullet grower
diet (PG) containing 14% protein and 2760 Kcal. of M.E./kg. and broiler finisher (BF) containing 20% protein and 3090 Kcal. of M.E./kg. At 18 weeks of age individual weekly feed wastage was recorded. This period of observation was carried out for three weeks. Feed and water were available ad libitum during both periods. The quantity of feed in the trough-type of feeder was kept between the level of § to § of the capacity of the feeder. Statistics: Analysis of variance and the F-test were applied to dependent variables in both periods. The null hypotheses were rejected at the significancy level a = .05, but for additional information all sources were stated for a < .10. RESULTS AND DISCUSSION During the first period separate analysis of variance for each single week confirmed that feed wastage was more affected by the genotype (strains) than by the composition of the diets. One of the strains consistently wasted more feed during all four weeks. Except for one week all the differences were significant (P < .05). The effect of diets did not produce significant differences in any of the four weeks of this period, but the overall feed wastage was lower for the broiler starter diet (Table 1). The interactions between diets and strains were not significant. Positional effect of the eight cage rows TABLE 1.—Average weekly feed wastage (8-12 weeks of age) per community cage of 12 birds Strain
Feed wastage (grams)
Diet
A
B
BS
CS
160
112
132
140
Note: BS = Broiler Starter CS = Chicken Starter
1667
RESEARCH NOTES
in the pen indicated highest feed wastage in the rows closest to the doors and side walls with less wastage in the center rows (P < .10). In the crosswise arrangement (four cages), feed wastage increased towards the working area, but this trend was even less pronounced than the effect of rows. Within a cage, feed wastage varied with the distance from the waterer. Linear regression on the length from the sides to the center of the feeder indicates a highest feed wastage at the center of the feeder. The differences in regression coefficients on the distance to the waterers were influenced more by strains (P < .10) than by the diets (P > .10). Assuming that the frequency of feeding was the same across the length of the feeder (which may have not been true in each cage), this fact could mean that the feeding responses in the central part were perhaps associated with a higher degree of selectiveness in respect to crumbles and/or with more "playing" with the feed. Another explanation could be that the subordinate and more frustrated birds were barred from the generally preferred feeding areas of the shortest distance to waterers. During the second observation period concerned with the individual variability in weekly feed wastage, the differences between the strains were nonsignificant. However, there was a trend for continuously higher wastage in the same strain as noted in the first period (Tables 1 and 2). Differences in feed wastage between diets were significant (P < .05) in one of the three weekly observations. Similarly to first period, birds fed the higher M.E. diet (broiler finisher) showed lower feed wastage. Cage tier levels, as an additional factor compared to previous period, did not significantly affect the amount of feed wasted. Nevertheless,
TABLE 2.—Average weekly feed wastage (18-21) weeks of age) for individual bird per cage Strain
Feed wastage (grams)
Diet
A
B
BF
PG
8.3
6.5
5.8
8.9
Tier Level Upper Lower 7.0
7.8
Note: BF = Broiler Finisher PG = Pullet Grower
higher wastage was observed in the lower tier level. Considering positional effect of the five cage rows in the pen, the highest feed wastage occurred in the row closest to the permanently operating exhaust fan. The contrast in feed wastage between this row and all four residual rows was significant (P < .05). Lowest wastage was observed in the center row. The total wastage per cage row within the pen appeared to have no relation to the allocation of light bulbs. The overall percentage of feed wasted was higher by younger birds in community cages (3.6%) than by individually allocated older birds (1.6%) in the second period. Further studies are considered to utilize the relatively large proportion of intrastrain variability associated with this trait. In present form the results suggest the possibility of decreasing feed wastage by more attention to those stimuli (primarily visual and audial) which in any way disturb the birds and cause fear or frustration.
REFERENCES Bauermann, J. F., 1959. An investigation of the effect of debeaking on feed wastage and fertility of Single Comb White Leghorns. Poultry Sci. 38: 1189. Reece, F. N., J. W. Deaton, J. D. May and K. N. May, 1971. Cage versus floor rearing of broiler chickens. Poultry Sci. 50: 1786-1790. Weiss, H. S., and E. Borbely, 1960. An evaluation of feed lost in the drinking water: Comparison among management systems and individual birds. Poultry Sci. 39: 1159-1166.