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Effects of Stocking Density on the Incidence of Scabby Hip Syndrome Among Broiler Chickens1
RESEARCH NOTES Effects of Stocking Density on the Incidence of Scabby Hip Syndrome Among Broiler Chickens1 F. G. PROUDFOOT and H. W. HULAN Research Station, Agriculture Canada, Kentville, Nova Scotia, B4N 1J5 (Received for publication January 15, 1985)
INTRODUCTION
MATERIALS AND METHODS
Scabby hip syndrome (SHS) is a dermatitis or inflammation of the skin, which appears to originate as a scratch around the lumbar and sacral regions of the back in broiler chickens. This skin condition is frequently associated with scab formation, which detracts from the appearance of the carcass at the time of slaughter and usually requires the removal of areas of skin containing the lesion(s). Although this skin removal does not result in carcass condemnation, it does result in downgrading. Field reports indicate that a severely afflicted flock may have the number of Grade A carcasses reduced by as much as 50%. This condition has been described by Harris (1977) as occurring in the southern regions of the United States during periods of high temperature and high relative humidity. He suggested that stocking density may play a role but did not provide critical data. An experiment, involving 1200 broiler chicks (600 males plus 600 females), was conducted to determine whether stocking density influenced the incidence of SHS in windowless housing under the climatic conditions that prevail in Nova Scotia during the summer season where temperatures and relative humidity (RH) ranged from 32 to 10 C and 32 to 100% RH, respectively, during the course of this experiment.
Eight pens in a windowless brooding and rearing house were used for this experiment. Each pen had an overall floor area of 12.6 m 2 . Floor space was altered by using a framed-wire netted moveable partition extending 75 cm above floor level to accommodate the different stocking-density treatments. Pens for the stocking-density treatments were selected at random with two pens assigned to each treatment group. Floor space allotments per pen were 12.6, 10.8, 8.8, and 6.8 m 2 . Planer shavings were used as litter to a depth of 5 cm in all pens. During the experiment, no additional litter material was used and no special treatment was administered to the litter. A total of 1200 Ross X Arbor Acre (feathersexed) 1-day-old chickens were randomly assigned to the eight pens with 75 male and 75 female chickens started in each pen. All birds received continuous lighting the first 48 hr after which they were subjected to intermittent lighting with continuous light and dark cycles of 4 and 2 hr, respectively. Light intensity was reduced from 25 lx at day-old to .5 lx at 14 days through the end of the experiment. Each pen was equipped with one hanging circular type waterer with a pan diameter of 35.6 cm. Cylindrical feeders were used with a pan diameter of 36.8 cm. Three feeders were allotted to each pen initially with an increase to 4 feeders at 22 days of age.
1 2
Contribution No. 1843. 4.184MJ/kcal.
A starter diet with 24% crude protein and 12.55 MJ/kg metabolizable energy was fed as crumbles to 21 days, and a finisher diet with 16% crude protein and 13.49 MJ/kg metab2001
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on June 7, 2015
ABSTRACT An experiment, involving 1200 broiler chickens, was conducted to evaluate the effects of stocking density (providing either 840, 720, 585, or 454 cm2 of floor space per bird) on the incidence of scabby hip syndrome at slaughter (42 days). The incidence of scabby hip syndrome was higher at the higher stocking density. Differences were significant for males and approached significance tor females (P<.05). Body weights (42 days) were lower among birds housed at the higher stocking density levels but other traits were not significantly affected (P>.05). (Key words: scabby hip syndrome, stocking density, broilers, chickens) 1985 Poultry Science 64:2001-2003
2002
PROUDFOOT AND HULAN
RESULTS AND DISCUSSION
Both male and female mortality was generally low, ranging from 3.01 to 4.99% for males and .33 to 4.00% for females, among treatment groups (Table 1). There were no significant stocking density treatment effects on either male or female mortality (P>.05). The incidence of SHS was higher among both male and female broiler chickens, grown under the higher stocking density regimens, with the differences significant (P<.05) for males and approaching significance (P<.05) for
females. The overall incidence appears higher than that found in industrial practice, presumably because carcasses showing any detectable evidence of dermatitis were considered affected, whereas under industrial practice, a minor dermatitic condition would be tolerated. It was observed that birds located in the higher stocking density regimens tended to walk over the backs of other reclined birds when moving about the pen area, thus providing evidence that the scratches were caused, at least in part, by clawed feet slipping and sliding down the hips and sides of birds in the reclined position. It was observed that birds reared under high stocking-density conditions, during periods of warm temperatures and high relative humidity, tend to feather out at a slower rate, thereby rendering them more susceptible to scratching injury because of the reduced feather cover over sensitive skin areas. This supports the report by Harris (1977) who observed that, under high stocking density conditions, feathers were lost from the hip and thigh areas of some birds and dermatitis was present. It was also observed that litter bedding material in the higher stocking density pens became damp and compacted during the last two weeks of the growing period, resulting in the production of ammonia which may have contributed to irritation of the scratched skin surfaces. A calculation of feed, consumed at 21 or 42 days of age per unit of body weight, revealed no significant differences, although the feed conversion ratio was numerically higher for the group reared under the highest stocking density (Table 2).
TABLE 1. Effect of stocking density on mortality and the incidence of scabby hip syndrome Mortality (0 to 42 days) Stocking density
Male
840 720 585 454 SEM1 1
Angles
Angles
(cm2 per bird started)
(4.64) (3.30) (3.01) (4.99)
Standard error of the mean.
•Significantly different (P<.05).
9.08 6.63 3.32 11.54 1.702
Female
Angles
(2.49) (1.33) ( .33). (4.00)
Angles
(%)
(%)
(%) 12.44 10.47 9.99 12.91 2.857
Incidence of scabby hip syndrome Male
Female
15.57 27.47 22.44 36.84 2.505*
( 7.21) (21.27) (14.56) (35.95)
(%) 20.28 31.08 31.92 36.27 4.780
(12.01) (26.66) (27.96) (35.00)
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on June 7, 2015
olizable energy was fed as pellets from 22 to 42 days (Proudfoot et al, 1984, Experiment 3). Data on the incidence of SHS dermatitis was collected by the examination of individual birds at the commercial processing plant, and individual birds showing any evidence of dermatitis were counted as having SHS. Other traits measured were: percentage mortality of males and females from 0 to 42 days; body weights of males and females at 21 and 42 days of age; feed conversion at 21 and 42 days; and monetary returns per chick started over the cost of feed and chicks. Starter and finisher diets were priced at 36.45 and 35.44 tf/kg, respectively. Chick costs were 40 and 30# for male and female chicks, respectively, and meat revenue was based on 124.75 #/kg live weight (minus birds condemned by the commercial processing plant during slaughter). The analyses of variance was based on pen means, and all percentage data were converted to arcsin angles for statistical analysis.
2003
RESEARCH NOTE
TABLE 2. Effect of stocking density on feed conversion, body weights, and monetary returns over feed and chick costs
Mean live body weights
Feed conversion Stocking density
to 21 days
to 42 days
21 days Male
Female
(cm 2 per bird started)
1
42 days Female
(g) 1.39 1.40 1.40 1.40 .008
1.86 1.86 1.86 1.88 .015
639 634 636 627 5.6
568 565 562 5 57
3.0
1916 1930 1897 1825 23.0
1627 1623 1580 1561 8.3*
64 65 64 57 1.5
Standard error of the mean.
'Significantly different (P-C05).
It is interesting t o n o t e t h a t m o n e t a r y returns, over t h e cost of feed and chicks, were n o t reduced except for t h e birds grown u n d e r t h e highest stocking density regimen; (an 8.5-cent r e d u c t i o n per bird) which a p p r o a c h e d significance ( P < . 0 5 ) . It should be p o i n t e d o u t , however, t h a t t h e calculation of m o n e t a r y revenue was based on a fixed price per unit of live weight (less weight of c o n d e m n e d birds) w i t h o u t regard t o carcass, t h u s t h e incidence of SHS w o u l d have n o d e t r i m e n t a l effect o n m o n e t a r y revenue. It is concluded t h a t high stocking density can play a significant role in t h e incidence of
s c a b b y hip s y n d r o m e t h a t can also be associated w i t h r e d u c e d m e a n live weight and reduced m o n e t a r y r e t u r n s p e r bird started.
REFERENCES Harris, G. C , 1977. Nutrition, bird density and litter effects on Scabby Hip (Dermatitis) of broilers. Pages 42—44 in Proc. Delmarva Poult. Health Conf. Proudfoot, F. G., H. W. Hulan, and K. B. McRae, 1984. The effects of dietary micro-nutrient fat and protein components in pelleted feeds on the incidence of Sudden Death Syndrome and other traits among male broiler chickens. Can. J. Anim. Sci. 64:159-164.
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on June 7, 2015
840 720 585 454 SEM1
Male
Monetary returns over the cost of feed and chicks per chick started
INTRODUCTION
MATERIALS AND METHODS
Scabby hip syndrome (SHS) is a dermatitis or inflammation of the skin, which appears to originate as a scratch around the lumbar and sacral regions of the back in broiler chickens. This skin condition is frequently associated with scab formation, which detracts from the appearance of the carcass at the time of slaughter and usually requires the removal of areas of skin containing the lesion(s). Although this skin removal does not result in carcass condemnation, it does result in downgrading. Field reports indicate that a severely afflicted flock may have the number of Grade A carcasses reduced by as much as 50%. This condition has been described by Harris (1977) as occurring in the southern regions of the United States during periods of high temperature and high relative humidity. He suggested that stocking density may play a role but did not provide critical data. An experiment, involving 1200 broiler chicks (600 males plus 600 females), was conducted to determine whether stocking density influenced the incidence of SHS in windowless housing under the climatic conditions that prevail in Nova Scotia during the summer season where temperatures and relative humidity (RH) ranged from 32 to 10 C and 32 to 100% RH, respectively, during the course of this experiment.
Eight pens in a windowless brooding and rearing house were used for this experiment. Each pen had an overall floor area of 12.6 m 2 . Floor space was altered by using a framed-wire netted moveable partition extending 75 cm above floor level to accommodate the different stocking-density treatments. Pens for the stocking-density treatments were selected at random with two pens assigned to each treatment group. Floor space allotments per pen were 12.6, 10.8, 8.8, and 6.8 m 2 . Planer shavings were used as litter to a depth of 5 cm in all pens. During the experiment, no additional litter material was used and no special treatment was administered to the litter. A total of 1200 Ross X Arbor Acre (feathersexed) 1-day-old chickens were randomly assigned to the eight pens with 75 male and 75 female chickens started in each pen. All birds received continuous lighting the first 48 hr after which they were subjected to intermittent lighting with continuous light and dark cycles of 4 and 2 hr, respectively. Light intensity was reduced from 25 lx at day-old to .5 lx at 14 days through the end of the experiment. Each pen was equipped with one hanging circular type waterer with a pan diameter of 35.6 cm. Cylindrical feeders were used with a pan diameter of 36.8 cm. Three feeders were allotted to each pen initially with an increase to 4 feeders at 22 days of age.
1 2
Contribution No. 1843. 4.184MJ/kcal.
A starter diet with 24% crude protein and 12.55 MJ/kg metabolizable energy was fed as crumbles to 21 days, and a finisher diet with 16% crude protein and 13.49 MJ/kg metab2001
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on June 7, 2015
ABSTRACT An experiment, involving 1200 broiler chickens, was conducted to evaluate the effects of stocking density (providing either 840, 720, 585, or 454 cm2 of floor space per bird) on the incidence of scabby hip syndrome at slaughter (42 days). The incidence of scabby hip syndrome was higher at the higher stocking density. Differences were significant for males and approached significance tor females (P<.05). Body weights (42 days) were lower among birds housed at the higher stocking density levels but other traits were not significantly affected (P>.05). (Key words: scabby hip syndrome, stocking density, broilers, chickens) 1985 Poultry Science 64:2001-2003
2002
PROUDFOOT AND HULAN
RESULTS AND DISCUSSION
Both male and female mortality was generally low, ranging from 3.01 to 4.99% for males and .33 to 4.00% for females, among treatment groups (Table 1). There were no significant stocking density treatment effects on either male or female mortality (P>.05). The incidence of SHS was higher among both male and female broiler chickens, grown under the higher stocking density regimens, with the differences significant (P<.05) for males and approaching significance (P<.05) for
females. The overall incidence appears higher than that found in industrial practice, presumably because carcasses showing any detectable evidence of dermatitis were considered affected, whereas under industrial practice, a minor dermatitic condition would be tolerated. It was observed that birds located in the higher stocking density regimens tended to walk over the backs of other reclined birds when moving about the pen area, thus providing evidence that the scratches were caused, at least in part, by clawed feet slipping and sliding down the hips and sides of birds in the reclined position. It was observed that birds reared under high stocking-density conditions, during periods of warm temperatures and high relative humidity, tend to feather out at a slower rate, thereby rendering them more susceptible to scratching injury because of the reduced feather cover over sensitive skin areas. This supports the report by Harris (1977) who observed that, under high stocking density conditions, feathers were lost from the hip and thigh areas of some birds and dermatitis was present. It was also observed that litter bedding material in the higher stocking density pens became damp and compacted during the last two weeks of the growing period, resulting in the production of ammonia which may have contributed to irritation of the scratched skin surfaces. A calculation of feed, consumed at 21 or 42 days of age per unit of body weight, revealed no significant differences, although the feed conversion ratio was numerically higher for the group reared under the highest stocking density (Table 2).
TABLE 1. Effect of stocking density on mortality and the incidence of scabby hip syndrome Mortality (0 to 42 days) Stocking density
Male
840 720 585 454 SEM1 1
Angles
Angles
(cm2 per bird started)
(4.64) (3.30) (3.01) (4.99)
Standard error of the mean.
•Significantly different (P<.05).
9.08 6.63 3.32 11.54 1.702
Female
Angles
(2.49) (1.33) ( .33). (4.00)
Angles
(%)
(%)
(%) 12.44 10.47 9.99 12.91 2.857
Incidence of scabby hip syndrome Male
Female
15.57 27.47 22.44 36.84 2.505*
( 7.21) (21.27) (14.56) (35.95)
(%) 20.28 31.08 31.92 36.27 4.780
(12.01) (26.66) (27.96) (35.00)
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on June 7, 2015
olizable energy was fed as pellets from 22 to 42 days (Proudfoot et al, 1984, Experiment 3). Data on the incidence of SHS dermatitis was collected by the examination of individual birds at the commercial processing plant, and individual birds showing any evidence of dermatitis were counted as having SHS. Other traits measured were: percentage mortality of males and females from 0 to 42 days; body weights of males and females at 21 and 42 days of age; feed conversion at 21 and 42 days; and monetary returns per chick started over the cost of feed and chicks. Starter and finisher diets were priced at 36.45 and 35.44 tf/kg, respectively. Chick costs were 40 and 30# for male and female chicks, respectively, and meat revenue was based on 124.75 #/kg live weight (minus birds condemned by the commercial processing plant during slaughter). The analyses of variance was based on pen means, and all percentage data were converted to arcsin angles for statistical analysis.
2003
RESEARCH NOTE
TABLE 2. Effect of stocking density on feed conversion, body weights, and monetary returns over feed and chick costs
Mean live body weights
Feed conversion Stocking density
to 21 days
to 42 days
21 days Male
Female
(cm 2 per bird started)
1
42 days Female
(g) 1.39 1.40 1.40 1.40 .008
1.86 1.86 1.86 1.88 .015
639 634 636 627 5.6
568 565 562 5 57
3.0
1916 1930 1897 1825 23.0
1627 1623 1580 1561 8.3*
64 65 64 57 1.5
Standard error of the mean.
'Significantly different (P-C05).
It is interesting t o n o t e t h a t m o n e t a r y returns, over t h e cost of feed and chicks, were n o t reduced except for t h e birds grown u n d e r t h e highest stocking density regimen; (an 8.5-cent r e d u c t i o n per bird) which a p p r o a c h e d significance ( P < . 0 5 ) . It should be p o i n t e d o u t , however, t h a t t h e calculation of m o n e t a r y revenue was based on a fixed price per unit of live weight (less weight of c o n d e m n e d birds) w i t h o u t regard t o carcass, t h u s t h e incidence of SHS w o u l d have n o d e t r i m e n t a l effect o n m o n e t a r y revenue. It is concluded t h a t high stocking density can play a significant role in t h e incidence of
s c a b b y hip s y n d r o m e t h a t can also be associated w i t h r e d u c e d m e a n live weight and reduced m o n e t a r y r e t u r n s p e r bird started.
REFERENCES Harris, G. C , 1977. Nutrition, bird density and litter effects on Scabby Hip (Dermatitis) of broilers. Pages 42—44 in Proc. Delmarva Poult. Health Conf. Proudfoot, F. G., H. W. Hulan, and K. B. McRae, 1984. The effects of dietary micro-nutrient fat and protein components in pelleted feeds on the incidence of Sudden Death Syndrome and other traits among male broiler chickens. Can. J. Anim. Sci. 64:159-164.
Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on June 7, 2015
840 720 585 454 SEM1
Male
Monetary returns over the cost of feed and chicks per chick started