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Incidence of an Abnormal Hock Condition in Male Turkeys as Influenced by Genetic Differences and by Hatch
Incidence of an Abnormal Hock Condition in Male Turkeys as Influenced by Genetic Differences and by Hatch A. S. JOHNSON
Canada Department of Agriculture, Ottawa, Canada* (Received for publication January 20, 1956)
V
MATERIALS AND METHODS
The pertinent data were obtained in 1955 from a flock of Empire White turkeys which are being selected for body size. This strain was obtained from a New York State breeder in 1953, as a sample of his pedigreed stock. The birds were randomly mated, without selection, in 1954, and in the fall of that year the first selections for body size were made. In 1955, the population consisted of the progeny of 20 sires, * Poultry Division, Experimental Farms Service, Ottawa.
each mated to 6 to 8 females. The poults were produced in three hatches two weeks apart, beginning on March 22. The rearing procedure was as follows. The wing-banded poults were randomized by sire and dam group into different sections of a battery brooder in which they were kept for one week. They were then moved to colony houses where they were brooded under gas brooders for 4 weeks. After this time, the poults were moved to a combined brooding and rearing porch and heat was provided, as required, by infra-red heat lamps; they were allowed out on the slatted porch as soon as weather permitted. At 12 weeks of age, they were transferred to range where they were reared, ages and sexes intermingled, for the balance of the growing period. The turkeys were shut in at night, as protection from predators, in range shelters with floors of two-inch slats spaced 2 inches apart. Body weights were obtained at 10, 12 and 24 weeks of age, by weighing to the nearest 20 grams with a Chatillon spring balance. The protein level of the ration was lowered from 27.4 percent in the first four weeks to 26 percent for the 4 to 8 week period and to 20 percent from 8 to 12 weeks. The ration was fed as mash to four weeks of age and in pellet form from then on. At 12 weeks of age, the birds were provided, in addition to the pelleted diet, a whole-grain mixture consisting of wheat, oats and barley in the proportions of 60— 30—10. All components of the diet were fed ad libitum. The diet was calculated to meet the recognized requirements for all
790
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ARIOUS types of hock disorder occur in turkeys. Some of these are caused by certain nutritional deficiencies and have been identified in birds as young as 2 to 4 weeks of age (Scott, 1953). More commonly, perosis or hock weakness is observed in turkeys at a much later age— 14 to 24 weeks—and is frequently associated with stress conditions of environment, such as rearing on porches with slatted floor (Pepper and Slinger, 1955; Slinger et al., 1955). The incidence of this condition in female turkeys is usually negligible. It is not to be confused with the type of hock disorder described by Hinshaw and Rosenwald (1953), which is caused by disease organisms and called staphylococcosis or synovitis; the latter could occur in equal frequency in both sexes. The present report concerns observations of genetic differences and differences associated with hatches in the incidence of the type of leg abnormality discussed by Slinger et al. (1955).
791
HOCK DISORDER IN TURKEYS
RESULTS AND DISCUSSION
Of the total number of males, 21.3 percent were affected with this hock disorder (Table 1). Only one female, out of a total of 501, displayed a similar condition. The distribution of the incidence by hatch, as well as the mean body weights for these hatches, is shown in Table 1. The association of the lower mean early growth rate in Hatch 3 with the low incidence of hock disorder, as well as the absence of this condition in the females, would seem to be evidence that early growth rate is an important contributing cause to this type of hock disorder, under certain conTABLE 1.—Incidence of hock disorder in turkey males, by hatch, with mean 10,12 and 24-week body weights (grams) Hatch 3 Total number of males 235 % affected 28.5 10-week weight 3,160 12-week weight 4,360 24-week weight 10,020
Hatch 2 Hatch 3
Total
171 162 568 26.3 5.6 21.3 3,140 2,970 3,100 4,270 4,110 4,260 9,990 10,050 10,020
ditions. However, when the males were classified, within hatches, into body weight classes on the basis of their 12-week weights, and the distribution of the incidence of hock disorder in these classes was tested by means of chi-square, the value obtained was not significant (P > .10), indicating a lack of association between the two characteristics. When the males of Hatches 1 and 2 which showed hock disorder were identified as to sire, there were very distinct differences in incidence between different sire families. The same tendency occurred within dam families but was not as noticeable, due to the more limited numbers per subgroup. The percentage incidence for different sire groups ranged from 0.0 to 71.4 in Hatch 1 and from 5.0 to 50.0 for the combined hatches (Table 2). Chi-square tests of the differences between sire groups yielded values for Hatches 1 and 2 and for combined hatches which were significant (X2 for combined hatches was 48.84, with TABLE 2.—Sire progeny groups (combined hatches) ranked as to incidence of hock disorder, with corresponding 12-week weights (grams)
Sire
No. of males
%hock disorder
2 3 1 13 17 19 7 11 10 15 18 6 8 16 5 9 14 20 12 4
20 34 37 36 31 20 33 22 37 30 36 31 24 29 22 23 23 29 31 20
50.0 41.2 40.5 38.9 38.7 25.0 24.2 22.7 18.9 16.7 13.9 12.9 12.5 10.3 9.1 8.7 8.7 6.9 6.4 5.0
fotal
568
21.3
Mean Rank 12-week Rank weight 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 16 17 18 19
4,400 4,190 4,320 4,300 4,330 4,110 4,233 4,010 4,400 4,330 4,240 4,360 4,360 4,180 4,090 4,180 4,360 4,250 4,150 4,270 4,260
1 10 4 5 3 13 9 15 1 3 8 2 2 11 14 11 2 7 12 6
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vitamins and minerals. The mash and pellets contained crystalline niacin (20 grams per ton) and vitamin E (10,000 I.U. per ton) because of their association with conditions of leg weakness (Scott, 1953). When the turkeys of the first hatch were 16 weeks of age, there was evidence of lameness and enlarged hocks among the males. The incidence increased gradually for about four weeks and then appeared to remain relatively constant. It was observed that, at 24 weeks of age, the Hatch 3 incidence was much lower than that of the other two hatches at the same age. There was no noticeable change in incidence from then to October 11, when all males were rated, without previous knowledge of their identity, as to whether they displayed marked lameness, enlarged hocks, and/or a "bowed out" or "bowed in" condition of the legs.
792
A. S. JOHNSON SUMMARY
A condition of enlarged hocks or perosis, generally accompanied by lameness, and occurring at about 16 to 20 weeks of age, was observed in a flock of Empire White turkey males. The incidence varied, among three hatches, from 5.6 to 28.5 percent, and, among 20 different sire groups, from 0.0 to 71.4 percent. There was no significant correlation between the percentage incidence of enlarged hocks and 12-week body weight. However, the low incidence of this defect occurred in the hatch which had the lowest early growth rate. Further experimentation on the factors responsible for the expression of this defect is required. REFERENCES Hinshaw, W. R., and A. S. Rosenwald, 1953. Turkey diseases. University of California Agric. Exp. Sta. Manual. Pepper, W. F., and S. J. Slinger, 19SS. Effect of arsonic acid derivatives and a high level of aureomycin on the performance of turkeys to 24 weeks of age. Poultry Sci. 34: 928-934. Scott, M. L., 1953. Prevention of the enlarged hock disorder in turkeys with niacin and vitamin E. Poultry Sci. 32: 670-677. Slinger. S. J., W. F. Pepper and D. Arthur, 1955. Effect of phosphorus, vitamin E and environment on growth and the incidence of perosis in turkeys. Poultry Sci. 34: 935-941.
NEWS AND NOTES (Continued from page 789) H. Steen, formerly with the American Dairy Association has joined the staff as Director of the Division of State Services; and W. A. Staempfli, Jr., formerly of Cornell University, will be the Chicken Broiler Promotion Specialist. SOUTH CAROLINA NOTES On July 1 Bobby D. Barnett joined the staff of the South Carolina Agricultural Experiment Station, Clemson, as Assistant Poultryman. Mr. Barnett received his Bachelor of Science degree
from the University of Arkansas in 1950. After a period of three years as the operator of a commercial broiler hatchery he returned to the University of Arkansas where he received the Master of Science degree. During the past three years he has been in attendance at the University of Wisconsin where he is completing his work for the Ph.D. degree in Poultry Husbandry and Biochemistry. He succeeds Dr. Edward C. Naber who resigned to accept a similar position at Ohio State University.
(Continued on page 822)
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P < .001). However, in Hatch 3, only 7 of the 20 sire groups displayed any of this hock disorder and the differences among sire groups were not significant. There was a rank correlation of .768, significant at the 1 percent probability level, between the levels of incidence among members of the same sire groups in Hatches 1 and 2. This is further evidence of genetic differences in incidence of this defect under conditions where it is expressed. There was no significant correspondence between the genotype which influenced this condition and the genotype associated with early rapid growth rate, as measured by analysis, within hatches, of the regression of percentage incidence on mean 12-week weight for sire groups. Furthermore, the rank correlations between the percentage of hock disorder and mean 12-week weight within sire families (.365 for Hatch 1, .248 of Hatch 2 and .201 for all Hatches) were non-significant. The variation in these traits among sire groups is shown in Table 2. From this it appears that, under conditions where this type of hock abnormality expresses itself, it may be possible to select for freedom from it and at the same time make progress in selection for growth rate, other things being equal.
Canada Department of Agriculture, Ottawa, Canada* (Received for publication January 20, 1956)
V
MATERIALS AND METHODS
The pertinent data were obtained in 1955 from a flock of Empire White turkeys which are being selected for body size. This strain was obtained from a New York State breeder in 1953, as a sample of his pedigreed stock. The birds were randomly mated, without selection, in 1954, and in the fall of that year the first selections for body size were made. In 1955, the population consisted of the progeny of 20 sires, * Poultry Division, Experimental Farms Service, Ottawa.
each mated to 6 to 8 females. The poults were produced in three hatches two weeks apart, beginning on March 22. The rearing procedure was as follows. The wing-banded poults were randomized by sire and dam group into different sections of a battery brooder in which they were kept for one week. They were then moved to colony houses where they were brooded under gas brooders for 4 weeks. After this time, the poults were moved to a combined brooding and rearing porch and heat was provided, as required, by infra-red heat lamps; they were allowed out on the slatted porch as soon as weather permitted. At 12 weeks of age, they were transferred to range where they were reared, ages and sexes intermingled, for the balance of the growing period. The turkeys were shut in at night, as protection from predators, in range shelters with floors of two-inch slats spaced 2 inches apart. Body weights were obtained at 10, 12 and 24 weeks of age, by weighing to the nearest 20 grams with a Chatillon spring balance. The protein level of the ration was lowered from 27.4 percent in the first four weeks to 26 percent for the 4 to 8 week period and to 20 percent from 8 to 12 weeks. The ration was fed as mash to four weeks of age and in pellet form from then on. At 12 weeks of age, the birds were provided, in addition to the pelleted diet, a whole-grain mixture consisting of wheat, oats and barley in the proportions of 60— 30—10. All components of the diet were fed ad libitum. The diet was calculated to meet the recognized requirements for all
790
Downloaded from http://ps.oxfordjournals.org/ by guest on June 4, 2015
ARIOUS types of hock disorder occur in turkeys. Some of these are caused by certain nutritional deficiencies and have been identified in birds as young as 2 to 4 weeks of age (Scott, 1953). More commonly, perosis or hock weakness is observed in turkeys at a much later age— 14 to 24 weeks—and is frequently associated with stress conditions of environment, such as rearing on porches with slatted floor (Pepper and Slinger, 1955; Slinger et al., 1955). The incidence of this condition in female turkeys is usually negligible. It is not to be confused with the type of hock disorder described by Hinshaw and Rosenwald (1953), which is caused by disease organisms and called staphylococcosis or synovitis; the latter could occur in equal frequency in both sexes. The present report concerns observations of genetic differences and differences associated with hatches in the incidence of the type of leg abnormality discussed by Slinger et al. (1955).
791
HOCK DISORDER IN TURKEYS
RESULTS AND DISCUSSION
Of the total number of males, 21.3 percent were affected with this hock disorder (Table 1). Only one female, out of a total of 501, displayed a similar condition. The distribution of the incidence by hatch, as well as the mean body weights for these hatches, is shown in Table 1. The association of the lower mean early growth rate in Hatch 3 with the low incidence of hock disorder, as well as the absence of this condition in the females, would seem to be evidence that early growth rate is an important contributing cause to this type of hock disorder, under certain conTABLE 1.—Incidence of hock disorder in turkey males, by hatch, with mean 10,12 and 24-week body weights (grams) Hatch 3 Total number of males 235 % affected 28.5 10-week weight 3,160 12-week weight 4,360 24-week weight 10,020
Hatch 2 Hatch 3
Total
171 162 568 26.3 5.6 21.3 3,140 2,970 3,100 4,270 4,110 4,260 9,990 10,050 10,020
ditions. However, when the males were classified, within hatches, into body weight classes on the basis of their 12-week weights, and the distribution of the incidence of hock disorder in these classes was tested by means of chi-square, the value obtained was not significant (P > .10), indicating a lack of association between the two characteristics. When the males of Hatches 1 and 2 which showed hock disorder were identified as to sire, there were very distinct differences in incidence between different sire families. The same tendency occurred within dam families but was not as noticeable, due to the more limited numbers per subgroup. The percentage incidence for different sire groups ranged from 0.0 to 71.4 in Hatch 1 and from 5.0 to 50.0 for the combined hatches (Table 2). Chi-square tests of the differences between sire groups yielded values for Hatches 1 and 2 and for combined hatches which were significant (X2 for combined hatches was 48.84, with TABLE 2.—Sire progeny groups (combined hatches) ranked as to incidence of hock disorder, with corresponding 12-week weights (grams)
Sire
No. of males
%hock disorder
2 3 1 13 17 19 7 11 10 15 18 6 8 16 5 9 14 20 12 4
20 34 37 36 31 20 33 22 37 30 36 31 24 29 22 23 23 29 31 20
50.0 41.2 40.5 38.9 38.7 25.0 24.2 22.7 18.9 16.7 13.9 12.9 12.5 10.3 9.1 8.7 8.7 6.9 6.4 5.0
fotal
568
21.3
Mean Rank 12-week Rank weight 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 16 17 18 19
4,400 4,190 4,320 4,300 4,330 4,110 4,233 4,010 4,400 4,330 4,240 4,360 4,360 4,180 4,090 4,180 4,360 4,250 4,150 4,270 4,260
1 10 4 5 3 13 9 15 1 3 8 2 2 11 14 11 2 7 12 6
Downloaded from http://ps.oxfordjournals.org/ by guest on June 4, 2015
vitamins and minerals. The mash and pellets contained crystalline niacin (20 grams per ton) and vitamin E (10,000 I.U. per ton) because of their association with conditions of leg weakness (Scott, 1953). When the turkeys of the first hatch were 16 weeks of age, there was evidence of lameness and enlarged hocks among the males. The incidence increased gradually for about four weeks and then appeared to remain relatively constant. It was observed that, at 24 weeks of age, the Hatch 3 incidence was much lower than that of the other two hatches at the same age. There was no noticeable change in incidence from then to October 11, when all males were rated, without previous knowledge of their identity, as to whether they displayed marked lameness, enlarged hocks, and/or a "bowed out" or "bowed in" condition of the legs.
792
A. S. JOHNSON SUMMARY
A condition of enlarged hocks or perosis, generally accompanied by lameness, and occurring at about 16 to 20 weeks of age, was observed in a flock of Empire White turkey males. The incidence varied, among three hatches, from 5.6 to 28.5 percent, and, among 20 different sire groups, from 0.0 to 71.4 percent. There was no significant correlation between the percentage incidence of enlarged hocks and 12-week body weight. However, the low incidence of this defect occurred in the hatch which had the lowest early growth rate. Further experimentation on the factors responsible for the expression of this defect is required. REFERENCES Hinshaw, W. R., and A. S. Rosenwald, 1953. Turkey diseases. University of California Agric. Exp. Sta. Manual. Pepper, W. F., and S. J. Slinger, 19SS. Effect of arsonic acid derivatives and a high level of aureomycin on the performance of turkeys to 24 weeks of age. Poultry Sci. 34: 928-934. Scott, M. L., 1953. Prevention of the enlarged hock disorder in turkeys with niacin and vitamin E. Poultry Sci. 32: 670-677. Slinger. S. J., W. F. Pepper and D. Arthur, 1955. Effect of phosphorus, vitamin E and environment on growth and the incidence of perosis in turkeys. Poultry Sci. 34: 935-941.
NEWS AND NOTES (Continued from page 789) H. Steen, formerly with the American Dairy Association has joined the staff as Director of the Division of State Services; and W. A. Staempfli, Jr., formerly of Cornell University, will be the Chicken Broiler Promotion Specialist. SOUTH CAROLINA NOTES On July 1 Bobby D. Barnett joined the staff of the South Carolina Agricultural Experiment Station, Clemson, as Assistant Poultryman. Mr. Barnett received his Bachelor of Science degree
from the University of Arkansas in 1950. After a period of three years as the operator of a commercial broiler hatchery he returned to the University of Arkansas where he received the Master of Science degree. During the past three years he has been in attendance at the University of Wisconsin where he is completing his work for the Ph.D. degree in Poultry Husbandry and Biochemistry. He succeeds Dr. Edward C. Naber who resigned to accept a similar position at Ohio State University.
(Continued on page 822)
Downloaded from http://ps.oxfordjournals.org/ by guest on June 4, 2015
P < .001). However, in Hatch 3, only 7 of the 20 sire groups displayed any of this hock disorder and the differences among sire groups were not significant. There was a rank correlation of .768, significant at the 1 percent probability level, between the levels of incidence among members of the same sire groups in Hatches 1 and 2. This is further evidence of genetic differences in incidence of this defect under conditions where it is expressed. There was no significant correspondence between the genotype which influenced this condition and the genotype associated with early rapid growth rate, as measured by analysis, within hatches, of the regression of percentage incidence on mean 12-week weight for sire groups. Furthermore, the rank correlations between the percentage of hock disorder and mean 12-week weight within sire families (.365 for Hatch 1, .248 of Hatch 2 and .201 for all Hatches) were non-significant. The variation in these traits among sire groups is shown in Table 2. From this it appears that, under conditions where this type of hock abnormality expresses itself, it may be possible to select for freedom from it and at the same time make progress in selection for growth rate, other things being equal.