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Performance and Interactions of Seven Egg Production Stocks in Three Cage Housing Regimes
UNIVERSITY-TEACHING AND RESEARCH
tige of a man, a college, or other institution means the weight, or influence each possesses, or the confidence inspired, depending on high character, past successes, or great and noble things already accomplished"? Do your colleagues, in the words of John Fischer (Is There a Teacher on the Faculty?" in Harper's Magazine, February, 1965, page 18) believe "in the Divine Right of the Professoriat to do as it damn well pleases, with a minimum of accountability to anyone, whether president, parent, tax payer, or student"? I remind you that on the plaque commemorating the naming of a building on a University campus in honour of one of the founders of this Association-Graham Hall —are the words: "He taught men to think"
Performance and Interactions of Seven Egg Production Stocks in Three Cage Housing Regimes R. E. COOK1 AND E. F. DEMBNICKI United States Department of Agriculture and Southern Regional Poultry Breeding Project, Athens, Georgia (Received for publication February 26, 1965)
HERE has been a definite trend in recent years toward higher bird densities in housing egg production stocks. Decreased income per bird or per dozen eggs has prompted egg producers to increase bird densities in an effort to reduce housing, equipment, and labor costs per bird. Many cage operators are increasing
T
1 Animal Husbandry Research Division, ARS, Beltsville, Maryland.
the bird density in cages by housing two or more pullets in a cage originally designed to accommodate a single bird. Although commercial egg producers generally use a Leghorn type bird in cage operations, little information is available to indicate whether strains differ in their ability to adapt to high density conditions in cage operations. Gowe (1956) reported that the relative performance of seven Leghorn strains in floor pens was not nec-
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
a.w.o.l. from the Psychology Department. He was found in the library, deep in thought, with Darwin's "Origin of Species" in his right hand, and the Bible in his left. He was attempting to decide whether he was his keeper's brother or his brother's keeper. Universities and colleges must teach Youth that Democracy is not synonymous with Freedom. Democracy is Freedom yoked with Responsibility and Duty. Freedom may mean Liberty, but not License. Liberty requires Loyalty. Universities must encourage young people to interpret Democracy in terms of Rights without neglect of Duties and Responsibilities. On your campus is Loyalty determined by minimum salary, tenure, fringe benefits and the size of the annual salary increment? Do your students graduate, knowing that "the pres-
17
18
R. E. COOK AND E. F. DEMBNICKI TABLE 1.—Average egg production for a 280 day period {Hen-housed)
Stock
Single
Double
Colony
Average
198.1 201.3 178.1 185.6 159.0 203.5 149.6 182.2
151.8 149.4 145.6 125.4 155.1 141.1 178.0 149.5
96.7 144.4 128.7 83.7 139.2 144.0 125.3 123.1
148.9 165.0 150.8 131.5 151.1 162.9 150.9 151.6
PROCEDURE
Seven egg production stocks including five commercial White Leghorns, one White Leghorn stock and one production type Rhode Island Red (R.I.R.) from experiment station flocks were used. Hatching eggs were obtained from each source and hatched in the same incubators, with eggs from each source being randomized into different trays and positions within the machines. The chicks were sexed at hatching time and the pullet chicks were brooded intermingled in floor pens from one day through eight weeks of age. At ap-
RESULTS AND DISCUSSION Egg production (hen-housed) for the seven stocks housed in single, double and colony cages for the 280 day period is shown in Table 1. The average egg production was superior for the birds housed in the single cages with an advantage of 32 and 59 eggs over the production of the
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
essarily an adequate test of the performance of the same strains in cages. He also concluded that some strains of S. C. White Leghorns apparently adapt themselves better to cage conditions than other strains. Lowry et al. (1956) found no evidence of a genotype-management interaction when comparing full sisters housed in floor pens and laying cages. Francis (1957) reported that some strains of Leghorns were better able to adapt themselves to cages than hybrids. He suggested further work to evaluate accurately the ability of strains to adapt themselves to cage conditions. There is very little published information as to whether egg production stocks differ in their ability to adapt to high density housing in cages. The purpose of this study was to evaluate the response of seven egg production stocks under three cage housing regimes.
proximately eight weeks of age the pullets were moved to range and housed in open range shelters from eight through twentyone weeks. A cage house containing single tiers of cages arranged in double rows with the cages back to back was used to conduct this study. Cages were arranged in blocks, with each block containing two 10 X 18 inch cages and one 20 X 18 inch cage. A total of 49 such blocks were provided. The pullets were housed at 147 days of age by taking 56 birds at random from each stock and assigning the pullets to seven blocks of eight birds each. Within each block one pullet was assigned at random to a single 10 inch cage, two pullets to a 10 inch cage and five pullets to the 20 inch cage making up the housing regimes of a single cage, double cage and 5 bird colony cage. The seven stocks were assigned to blocks at random throughout the house. All pullets were debeaked at housing. An all mash commercial layer diet was fed ad libitum to all birds. Feeder and water space varied with the housing regimes due to the density of birds. Data were collected on daily egg production per cage, egg weights and egg quality traits for a seven-day period at 200 and 350 days of age, body weights at 147 and 42 7 days of age, and mortality by weeks. The birds were maintained in the laying cages for 280 days with production being recorded in 28 day periods. The data obtained were analyzed by the analysis of variance (Snedecor, 1956).
19
PERFORMANCE IN CAGE HOUSING REGIMES TABLE 3.—Laying mortality {percent) Stock
Single
Double
Colony
Average
0.0 0.0 14.3 0.0 0.0 0.0 14.3 4.1
14.3 14.3 21.4 14.3 0.0 7.1 7.1 11.2
34.3 20.0 17.1 37.1 8.6 25.7 31.4 24.9
16.2 11.4 17.6 17.1 2.9 10.9 17.6 13.4
for laying mortality are presented in Table 3. The average mortality for the 280 day laying period was 13.4% with a range among stocks from 2.9 to 17.6%. Mortality differences among the three housing regimes were more striking, with mortality rates of 4.1, 11.2, and 24.9% for the single, double and colony cages, respectively. An analysis of variance of these data as presented in Table 4 indicates significant (P < .05) differences among stocks and highly significant (P < .01) differences among the housing methods. The mortality increased with density for all stocks with the exception of stock number 9 which had a higher mortality in single cages than in the double cages and stock number 4 which had slightly higher mortality in the double cages. The interaction of stock X treatment was nonsignificant, indicating that the stocks reacted similarly to the housing regimes. The significant difference among stocks (P < .05) was probably enhanced by the extremely low mortality of stock number 6 in all housing regimes.
TABLE 2.—Analysis of variance for hen-housed egg production TABLE 4.—Analysis of variance for laying mortality Source
d.f.
Total Reps. Stocks (S) Treat. (T) SXT Error
1451 6 6 2 12 119
S.S. 299,258.2 10,329.9 14,687.5 84,398.1 37,550.1 160,371.4
M.S. 1,721.6 2,447.9 42,199.1** 3,129.2** 1,347.6
1 Total degrees of freedom were reduced in the least squares analysis due to one missing cell. ** IndicatesP<.01.
Source
d.f.
S.S.
M.S.
Total Reps. Stock (S) Treat. (T) SXT Error
145 6 6 2 12 119
38,964.7 315.2 2,546.7 6,217.9 3,573.2 22,115.1
52.5 424.4* 3,108.9** 297.8 185.8
* Indicates P < . 0 5 . ** Indicates P < . 0 1 .
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
pullets in a double cage and colony cage respectively. The performance of six out of the seven stocks was superior in single cages with stock number 9 having production in the double cage superior to the single caged birds. Stock number 8 performed slightly better in the colony cage than in the double cages. A leastsquare analysis of these data indicated highly significant (P < .01) differences between the housing regimes (treatments) as shown in Table 2. The interaction of stock X housing regime was also highly significant (P < .01). The interaction of stock X housing regime is evident from the inspection of the data in Table 1. The performance of stock number 8 cannot be explained on the basis of mortality differences, whereas the production of stock 9 reflected differences in mortality as shown in Table 3. There were no significant differences among the seven stocks for henhoused production when considering the total production in the three housing regimes. Data on survivor egg production reflected the same trends as hen-housed production and are not presented for the sake of brevity. It was interesting that the production R.I.R. (stock 3) performed as well as or superior to many of the White Leghorn stocks. Mortality during the laying period varied considerably among stocks and among the three housing regimes. Averages
20
R. E. COOK AND E. F. DEMBNICKI TABLE 5.—Egg weights at 200 and 350 days of age in grams Double cage
Single cage Stock 1 3 4 S 6 8 9 Average
Colony cage
Average weights
200 day
350 day
200 day
350 day
200 day
350 day
200 day
350 day
53.7 53.3 50.5 57.1 54.8 55.6 53.3 54.0
61.6 59.0 62.6 63.1 61.0 61.8 63.0 61.7
55.2 55.8 56.3 54.9 55.2 54.8 57.2 55.6
64.7 59.3 65.7 61.3 61.2 61.1 64.7 62.6
55.9 53.1 52.5 56.3 56.1 54.0 56.4 54.9
62.6 59.6 62.7 63.6 61.8 60.6 63.7 62.1
54.9 54.1 53.1 56.1 55.4 54.8 55.6 54.8
62.9 59.3 63.7 62.7 61.3 61.2 63.8 62.1
TABLE 6.—Percent eggs showing blood and meat spots Stock
Single
1 3 4 5 6 8 9 Average
25.5 37.0 14.5 28.0 22.5 35.3 32.4 27.9
Double Colony 29.1 62.9 24.1 19.7 31.2 24.1 23.6 30.7
23.2 51.6 30.3 18.6 23.9 29.7 16.8 27.7
Ave. + S.E. 25.9 + 2.34 50.5 + 3.05 23.0 + 2.92 22.1+2.78 25.8 + 3.15 29.7 + 3.10 24.3+3.93 28.8
was superior in one housing regime while other stocks seemed to excel in another regime. Perhaps differences in sexual maturity and consequently greater individual variability in the egg weights contributed to the differences observed early in the production period. Specific gravity determinations were also made on all eggs weighed at 200 days of age. No stock or treatment differences in specific gravity were noted. Poultrymen have frequently claimed that high density housing systems contributed to the incidence of blood and meat spots found in eggs. Results in this study do not substantiate this claim. The blood and meat spots data were recorded on all eggs weighed at 200 and 350 days of age by classifying each egg as clear if no visible spots were present and defective if either or both blood and meat were present. The percent defective eggs by stock and housing regime are presented in Table 6. It is evident from an examination of the averages of stocks for each housing method that the only striking difference was between the R.I.R. (stock 3) and the W.L. stocks. The incidence of blood spots for the R.I.R. was about twice as great as for the W.L. stocks. An analysis of the data including this stock indicated highly significant differences (P < .01) between stocks. However, an analysis of the W.L. stocks alone indicated no significant differences.
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
Body weights at 147 days and at 427 days of age were compared to determine the influence of housing regime. Highly significant differences (P<.01) among stocks were evident at housing and at the completion of the test when the R.I.R. stock was included. When the weights of the six W.L. stocks were considered independently of the R.I.R., no significant differences were found. The method of housing did not have any significant influence upon body weights at either of the weighing periods. The average egg weight by stock and method of housing are presented in Table 5 for both weighing periods. An analysis of variance of the data indicated significant differences (P<.05) among stocks at 200 days of age. When measured at 350 days of age, no significant differences were evident. A stock X treatment interaction was evident for both 200 and 3S0 day egg weights, indicating no consistent relationship between the stocks and the housing regimes. The egg weights of some stocks
21
PERFORMANCE IN CAGE HOUSING REGIMES
SUMMARY
Wide differences were also observed between stocks and housing regimes for laying mortality, with mortality increasing as density increased. There was no evidence of interaction between stocks and housing regimes for body weights or egg quality traits. REFERENCES Francis, D. W., 1957. A comparison of seven strains of purebreds and hybrids in cages. Poultry Sci. 36: 178-181. Gowe, R. S., 1956. Environment and poultry breeding problems. 2. A comparison of the egg production of 7 S. C. White Leghorn strains housed in laying batteries and floor pens. Poultry Sci. 35: 430-435. Lowry, D. C, I. M. Lerner and L. W Taylor, 1956. Intraflock genetic merit under floor and cage managements. Poultry Sci. 34: 1034-1043. Snedecor, G. W., 1956. Statistical Methods, Iowa State College Press, Ames, Iowa.
The Enhancement of Chlortetracycline Activity Against Pasteurella multocida with Sodium Sulfate* E. E. STUART, R. D. KEENUM, L. E. OUSTERHOUT AND H. W.
BRUINS
The Quaker Oats Company Research Laboratories, Decatur, Alabama, and Barrington, Illinois (Received for publication May 6, 1965)
INTRODUCTION
I
T IS known that the presence of calcium ions in the intestine interfere with the absorption of tetracycline antibiotics by the chicken (Price et at., 1958-1959). Thus, blood levels of tetracycline antibiotics can be increased by reducing the level of dietary calcium (Riser and Roberts, 1957), by using a relatively insoluble calcium source, e.g. CaSO* (Pensack et al., 1959; Stokstad, 1959), or by adding an organic acid which binds C a + + (Eisner * Presented at Annual Meeting, Stillwater, Oklahoma, August 19-23, 1963, Poultry Sci. 42:1311.
etal, 1953; Gray et al, 1953; 1954). It has been shown that blood levels of antibiotic increased by such dietary modifications enhance the activity of the drug against coccidiosis (Peterson, 1958), C.R.D. (Peterson and Hendrix, 1959), Salmonella gallinarum (Riser, 1959), and infectious synovitis (Shelton and Olson, 1958). Pensack et al. (1959) and Nelson and Peeler (1961) reported that the addition of sodium sulfate to feeds containing chlortetracycline increased blood levels of the antibiotic. Since this method appeared to have certain practical advantages over other methods of potentiation, the experiments to be reported were undertaken to
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
Seven egg production stocks including five commercial White Leghorn type, one White Leghorn, and one Rhode Island Red were hatched and reared together. A random sample of 56 pullets from each stock was housed at 147 days of age in laying cages using three housing regimes. The regimes were a single cage, double cage and a five bird colony cage. There were highly significant differences among the housing regimes in hen-housed egg production with the pullets housed individually having a 32 and 59 egg advantage in production over the pullets housed for a 280-day laying period in the double or colony cages respectively. The interaction of stock X housing regime was also highly significant.
tige of a man, a college, or other institution means the weight, or influence each possesses, or the confidence inspired, depending on high character, past successes, or great and noble things already accomplished"? Do your colleagues, in the words of John Fischer (Is There a Teacher on the Faculty?" in Harper's Magazine, February, 1965, page 18) believe "in the Divine Right of the Professoriat to do as it damn well pleases, with a minimum of accountability to anyone, whether president, parent, tax payer, or student"? I remind you that on the plaque commemorating the naming of a building on a University campus in honour of one of the founders of this Association-Graham Hall —are the words: "He taught men to think"
Performance and Interactions of Seven Egg Production Stocks in Three Cage Housing Regimes R. E. COOK1 AND E. F. DEMBNICKI United States Department of Agriculture and Southern Regional Poultry Breeding Project, Athens, Georgia (Received for publication February 26, 1965)
HERE has been a definite trend in recent years toward higher bird densities in housing egg production stocks. Decreased income per bird or per dozen eggs has prompted egg producers to increase bird densities in an effort to reduce housing, equipment, and labor costs per bird. Many cage operators are increasing
T
1 Animal Husbandry Research Division, ARS, Beltsville, Maryland.
the bird density in cages by housing two or more pullets in a cage originally designed to accommodate a single bird. Although commercial egg producers generally use a Leghorn type bird in cage operations, little information is available to indicate whether strains differ in their ability to adapt to high density conditions in cage operations. Gowe (1956) reported that the relative performance of seven Leghorn strains in floor pens was not nec-
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
a.w.o.l. from the Psychology Department. He was found in the library, deep in thought, with Darwin's "Origin of Species" in his right hand, and the Bible in his left. He was attempting to decide whether he was his keeper's brother or his brother's keeper. Universities and colleges must teach Youth that Democracy is not synonymous with Freedom. Democracy is Freedom yoked with Responsibility and Duty. Freedom may mean Liberty, but not License. Liberty requires Loyalty. Universities must encourage young people to interpret Democracy in terms of Rights without neglect of Duties and Responsibilities. On your campus is Loyalty determined by minimum salary, tenure, fringe benefits and the size of the annual salary increment? Do your students graduate, knowing that "the pres-
17
18
R. E. COOK AND E. F. DEMBNICKI TABLE 1.—Average egg production for a 280 day period {Hen-housed)
Stock
Single
Double
Colony
Average
198.1 201.3 178.1 185.6 159.0 203.5 149.6 182.2
151.8 149.4 145.6 125.4 155.1 141.1 178.0 149.5
96.7 144.4 128.7 83.7 139.2 144.0 125.3 123.1
148.9 165.0 150.8 131.5 151.1 162.9 150.9 151.6
PROCEDURE
Seven egg production stocks including five commercial White Leghorns, one White Leghorn stock and one production type Rhode Island Red (R.I.R.) from experiment station flocks were used. Hatching eggs were obtained from each source and hatched in the same incubators, with eggs from each source being randomized into different trays and positions within the machines. The chicks were sexed at hatching time and the pullet chicks were brooded intermingled in floor pens from one day through eight weeks of age. At ap-
RESULTS AND DISCUSSION Egg production (hen-housed) for the seven stocks housed in single, double and colony cages for the 280 day period is shown in Table 1. The average egg production was superior for the birds housed in the single cages with an advantage of 32 and 59 eggs over the production of the
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
essarily an adequate test of the performance of the same strains in cages. He also concluded that some strains of S. C. White Leghorns apparently adapt themselves better to cage conditions than other strains. Lowry et al. (1956) found no evidence of a genotype-management interaction when comparing full sisters housed in floor pens and laying cages. Francis (1957) reported that some strains of Leghorns were better able to adapt themselves to cages than hybrids. He suggested further work to evaluate accurately the ability of strains to adapt themselves to cage conditions. There is very little published information as to whether egg production stocks differ in their ability to adapt to high density housing in cages. The purpose of this study was to evaluate the response of seven egg production stocks under three cage housing regimes.
proximately eight weeks of age the pullets were moved to range and housed in open range shelters from eight through twentyone weeks. A cage house containing single tiers of cages arranged in double rows with the cages back to back was used to conduct this study. Cages were arranged in blocks, with each block containing two 10 X 18 inch cages and one 20 X 18 inch cage. A total of 49 such blocks were provided. The pullets were housed at 147 days of age by taking 56 birds at random from each stock and assigning the pullets to seven blocks of eight birds each. Within each block one pullet was assigned at random to a single 10 inch cage, two pullets to a 10 inch cage and five pullets to the 20 inch cage making up the housing regimes of a single cage, double cage and 5 bird colony cage. The seven stocks were assigned to blocks at random throughout the house. All pullets were debeaked at housing. An all mash commercial layer diet was fed ad libitum to all birds. Feeder and water space varied with the housing regimes due to the density of birds. Data were collected on daily egg production per cage, egg weights and egg quality traits for a seven-day period at 200 and 350 days of age, body weights at 147 and 42 7 days of age, and mortality by weeks. The birds were maintained in the laying cages for 280 days with production being recorded in 28 day periods. The data obtained were analyzed by the analysis of variance (Snedecor, 1956).
19
PERFORMANCE IN CAGE HOUSING REGIMES TABLE 3.—Laying mortality {percent) Stock
Single
Double
Colony
Average
0.0 0.0 14.3 0.0 0.0 0.0 14.3 4.1
14.3 14.3 21.4 14.3 0.0 7.1 7.1 11.2
34.3 20.0 17.1 37.1 8.6 25.7 31.4 24.9
16.2 11.4 17.6 17.1 2.9 10.9 17.6 13.4
for laying mortality are presented in Table 3. The average mortality for the 280 day laying period was 13.4% with a range among stocks from 2.9 to 17.6%. Mortality differences among the three housing regimes were more striking, with mortality rates of 4.1, 11.2, and 24.9% for the single, double and colony cages, respectively. An analysis of variance of these data as presented in Table 4 indicates significant (P < .05) differences among stocks and highly significant (P < .01) differences among the housing methods. The mortality increased with density for all stocks with the exception of stock number 9 which had a higher mortality in single cages than in the double cages and stock number 4 which had slightly higher mortality in the double cages. The interaction of stock X treatment was nonsignificant, indicating that the stocks reacted similarly to the housing regimes. The significant difference among stocks (P < .05) was probably enhanced by the extremely low mortality of stock number 6 in all housing regimes.
TABLE 2.—Analysis of variance for hen-housed egg production TABLE 4.—Analysis of variance for laying mortality Source
d.f.
Total Reps. Stocks (S) Treat. (T) SXT Error
1451 6 6 2 12 119
S.S. 299,258.2 10,329.9 14,687.5 84,398.1 37,550.1 160,371.4
M.S. 1,721.6 2,447.9 42,199.1** 3,129.2** 1,347.6
1 Total degrees of freedom were reduced in the least squares analysis due to one missing cell. ** IndicatesP<.01.
Source
d.f.
S.S.
M.S.
Total Reps. Stock (S) Treat. (T) SXT Error
145 6 6 2 12 119
38,964.7 315.2 2,546.7 6,217.9 3,573.2 22,115.1
52.5 424.4* 3,108.9** 297.8 185.8
* Indicates P < . 0 5 . ** Indicates P < . 0 1 .
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
pullets in a double cage and colony cage respectively. The performance of six out of the seven stocks was superior in single cages with stock number 9 having production in the double cage superior to the single caged birds. Stock number 8 performed slightly better in the colony cage than in the double cages. A leastsquare analysis of these data indicated highly significant (P < .01) differences between the housing regimes (treatments) as shown in Table 2. The interaction of stock X housing regime was also highly significant (P < .01). The interaction of stock X housing regime is evident from the inspection of the data in Table 1. The performance of stock number 8 cannot be explained on the basis of mortality differences, whereas the production of stock 9 reflected differences in mortality as shown in Table 3. There were no significant differences among the seven stocks for henhoused production when considering the total production in the three housing regimes. Data on survivor egg production reflected the same trends as hen-housed production and are not presented for the sake of brevity. It was interesting that the production R.I.R. (stock 3) performed as well as or superior to many of the White Leghorn stocks. Mortality during the laying period varied considerably among stocks and among the three housing regimes. Averages
20
R. E. COOK AND E. F. DEMBNICKI TABLE 5.—Egg weights at 200 and 350 days of age in grams Double cage
Single cage Stock 1 3 4 S 6 8 9 Average
Colony cage
Average weights
200 day
350 day
200 day
350 day
200 day
350 day
200 day
350 day
53.7 53.3 50.5 57.1 54.8 55.6 53.3 54.0
61.6 59.0 62.6 63.1 61.0 61.8 63.0 61.7
55.2 55.8 56.3 54.9 55.2 54.8 57.2 55.6
64.7 59.3 65.7 61.3 61.2 61.1 64.7 62.6
55.9 53.1 52.5 56.3 56.1 54.0 56.4 54.9
62.6 59.6 62.7 63.6 61.8 60.6 63.7 62.1
54.9 54.1 53.1 56.1 55.4 54.8 55.6 54.8
62.9 59.3 63.7 62.7 61.3 61.2 63.8 62.1
TABLE 6.—Percent eggs showing blood and meat spots Stock
Single
1 3 4 5 6 8 9 Average
25.5 37.0 14.5 28.0 22.5 35.3 32.4 27.9
Double Colony 29.1 62.9 24.1 19.7 31.2 24.1 23.6 30.7
23.2 51.6 30.3 18.6 23.9 29.7 16.8 27.7
Ave. + S.E. 25.9 + 2.34 50.5 + 3.05 23.0 + 2.92 22.1+2.78 25.8 + 3.15 29.7 + 3.10 24.3+3.93 28.8
was superior in one housing regime while other stocks seemed to excel in another regime. Perhaps differences in sexual maturity and consequently greater individual variability in the egg weights contributed to the differences observed early in the production period. Specific gravity determinations were also made on all eggs weighed at 200 days of age. No stock or treatment differences in specific gravity were noted. Poultrymen have frequently claimed that high density housing systems contributed to the incidence of blood and meat spots found in eggs. Results in this study do not substantiate this claim. The blood and meat spots data were recorded on all eggs weighed at 200 and 350 days of age by classifying each egg as clear if no visible spots were present and defective if either or both blood and meat were present. The percent defective eggs by stock and housing regime are presented in Table 6. It is evident from an examination of the averages of stocks for each housing method that the only striking difference was between the R.I.R. (stock 3) and the W.L. stocks. The incidence of blood spots for the R.I.R. was about twice as great as for the W.L. stocks. An analysis of the data including this stock indicated highly significant differences (P < .01) between stocks. However, an analysis of the W.L. stocks alone indicated no significant differences.
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
Body weights at 147 days and at 427 days of age were compared to determine the influence of housing regime. Highly significant differences (P<.01) among stocks were evident at housing and at the completion of the test when the R.I.R. stock was included. When the weights of the six W.L. stocks were considered independently of the R.I.R., no significant differences were found. The method of housing did not have any significant influence upon body weights at either of the weighing periods. The average egg weight by stock and method of housing are presented in Table 5 for both weighing periods. An analysis of variance of the data indicated significant differences (P<.05) among stocks at 200 days of age. When measured at 350 days of age, no significant differences were evident. A stock X treatment interaction was evident for both 200 and 3S0 day egg weights, indicating no consistent relationship between the stocks and the housing regimes. The egg weights of some stocks
21
PERFORMANCE IN CAGE HOUSING REGIMES
SUMMARY
Wide differences were also observed between stocks and housing regimes for laying mortality, with mortality increasing as density increased. There was no evidence of interaction between stocks and housing regimes for body weights or egg quality traits. REFERENCES Francis, D. W., 1957. A comparison of seven strains of purebreds and hybrids in cages. Poultry Sci. 36: 178-181. Gowe, R. S., 1956. Environment and poultry breeding problems. 2. A comparison of the egg production of 7 S. C. White Leghorn strains housed in laying batteries and floor pens. Poultry Sci. 35: 430-435. Lowry, D. C, I. M. Lerner and L. W Taylor, 1956. Intraflock genetic merit under floor and cage managements. Poultry Sci. 34: 1034-1043. Snedecor, G. W., 1956. Statistical Methods, Iowa State College Press, Ames, Iowa.
The Enhancement of Chlortetracycline Activity Against Pasteurella multocida with Sodium Sulfate* E. E. STUART, R. D. KEENUM, L. E. OUSTERHOUT AND H. W.
BRUINS
The Quaker Oats Company Research Laboratories, Decatur, Alabama, and Barrington, Illinois (Received for publication May 6, 1965)
INTRODUCTION
I
T IS known that the presence of calcium ions in the intestine interfere with the absorption of tetracycline antibiotics by the chicken (Price et at., 1958-1959). Thus, blood levels of tetracycline antibiotics can be increased by reducing the level of dietary calcium (Riser and Roberts, 1957), by using a relatively insoluble calcium source, e.g. CaSO* (Pensack et al., 1959; Stokstad, 1959), or by adding an organic acid which binds C a + + (Eisner * Presented at Annual Meeting, Stillwater, Oklahoma, August 19-23, 1963, Poultry Sci. 42:1311.
etal, 1953; Gray et al, 1953; 1954). It has been shown that blood levels of antibiotic increased by such dietary modifications enhance the activity of the drug against coccidiosis (Peterson, 1958), C.R.D. (Peterson and Hendrix, 1959), Salmonella gallinarum (Riser, 1959), and infectious synovitis (Shelton and Olson, 1958). Pensack et al. (1959) and Nelson and Peeler (1961) reported that the addition of sodium sulfate to feeds containing chlortetracycline increased blood levels of the antibiotic. Since this method appeared to have certain practical advantages over other methods of potentiation, the experiments to be reported were undertaken to
Downloaded from http://ps.oxfordjournals.org/ at Ritsumeikan University on June 16, 2015
Seven egg production stocks including five commercial White Leghorn type, one White Leghorn, and one Rhode Island Red were hatched and reared together. A random sample of 56 pullets from each stock was housed at 147 days of age in laying cages using three housing regimes. The regimes were a single cage, double cage and a five bird colony cage. There were highly significant differences among the housing regimes in hen-housed egg production with the pullets housed individually having a 32 and 59 egg advantage in production over the pullets housed for a 280-day laying period in the double or colony cages respectively. The interaction of stock X housing regime was also highly significant.