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Method and Frequency of Artificial Insemination and Turkey Fertility
717
BODY TEMPERATURE
No special technique was used to revive the birds in either of the experiments. After removal from the cold chamber, the birds were placed in the pen with the controls.
REFERENCES Moreng, R. E., and C. S. Shaffner, 1951. Lethal internal temperatures for the chicken from fertile egg to mature bird. Poultry Sci. 30: 255-266. Reece, F. N., and J. W. Deaton, 1968. A radio transmitter for telemetering body temperatures of chickens. Poultry Sci. 47: 424-428.
Method and Frequency of Artificial Insemination and Turkey Fertility KARL E. NESTOR AND KEITH I. BROWN Ohio Agricultural Research and Development Center, Wooster, Ohio 44691 (Received for publication July 19, 1967)
L
OW fertility is still a serious problem ' in producing turkey hatching eggs even though most turkeys are artificially inseminated. Generally, the fertility of turkey eggs is relatively high at the beginning of the breeding season and then declines as the season progresses. Several factors may be responsible for the seasonal decline in fertility. Among these are faulty insemination techniques, as shown by Ogasawara and Rooney (1966), and mechanical spread of infectious organisms from hen to hen by the insemination technique. Many turkey breeders and turkey hatching egg producers are now using a disposable plastic tube for insemination in order to prevent spread of vaginal infection. Although the use of the tube method of insemination has become an established practice commercially, there has been little experimental evidence to show that it is a su-
perior method. In a preliminary report of the present work, Nestor and Brown (1966) observed that the tube method of insemination gave higher fertility than the syringe method. Bajpai and Brown (1964) compared the syringe and rod methods of insemination. Fertility obtained with the two methods of insemination was identical. Burrows and Marsden (1938) inseminated turkeys repeatedly at intervals of 1, 2, 3, and 4 weeks and found no apparent tendency for fertility to decline with increasing length of interval between successive inseminations. McCartney (1952) found that increasing the insemination interval from 2 to 4 weeks resulted in a highly significant decrease in fertility, but in a later study (1954) observed no significant difference in fertility between intervals of 2 and 3 weeks. More recent work (Bajpai and Brown, 1964; Nestor and Brown, 1966; and Ogasawara and Rooney,
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
SUMMARY A telemetry technique was used to monitor the body temperature of broiler chicks. Altering body temperature of broilers at 1, 8, 15, and 22 days of age to an average of 24.4°, 26.0°, 33.1°, and 39.6°C, respectively, had no significant effect on 8-week body weight, mortality or condemnation when compared to the controls. Subjecting
female broiler chicks at 1 and 7 days of age to an ambient temperature of — 3.9°C. until all birds became comatose had no significant effect on 8-week body weight, mortality, or condemnation.
718
K. E. NESTOR AND K. I. BROWN
1966) indicates that fertility is increased by weekly inseminations in comparison to bi-weekly inseminations, especially late in the laying season. The purpose of this experiment was to determine the influence of method and frequency of insemination on turkey fertility. MATERIALS AND METHODS
RESULTS AND DISCUSSION
The percent fertility obtained with various treatments is summarized in Table 1. Fertility obtained by the use of the tube method was consistently higher than that obtained with the other two methods. However, the differences among methods of insemination were significant (P < .05) only in comparisons made very late in the laying season (18 to 27 weeks and 28 to 36
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
The methods of insemination compared in this experiment were the syringe, tube, and glass rod. Semen was inseminated by means of a 0.25 cc. glass syringe (B.D. Yale with glass Luer tip) with the syringe method. The tube method of insemination used in this experiment consisted of attaching a rigid plastic tube (5 mm. X .4 cc. X 10.16 cm.) to a section of plastic tubing, dipping the tube into semen, and blowing the semen into the oviduct by mouth. A different tube was used for each hen. The tubes were washed and re-used. They were washed in water containing detergent and then allowed to soak in a 95% ethyl alcohol solution for at least one day. After soaking, they were dried and re-used. The glass rod method was similar to the method described by Bajpai and Brown (1964). A common glass rod (approximately 3.0 mm. X 15 cm.) was used to inseminate all hens in a group in this study. A concave cup was formed on one end of the rod by heating. The end with the depression was dipped into the semen and then inserted in the oviduct and wiped clean. The syringe and rod methods would be conducive to spread of infectious organisms from hen to hen since repeated inseminations were made without sterilization. The posssibility was minimized with the tube method. The hens in all trials were from different flocks of a strain selected for and exhibiting high egg production. This strain was
initiated in 1960 from a randombred control population (McCartney, 1964) and has changed very little in body weight since that time. Most of the comparisons were made during hot weather late in the laying season when the fertility level is normally low. Pooled semen from 20 to 30 males was divided into aliquots. A different aliquot was used with each method of insemination. No effort was made to keep constant the amount of semen inseminated per hen with the different methods of insemination. However, an excessive amount of semen (in excess of 0.02 cc. per hen) was used with the tube and syringe methods of insemination. Semen was collected and held at 15°C. during insemination. Eggs were set at weekly intervals. They were candled on the seventh day of incubation. Eggs classified as infertiles were broken open and examined macroscopically in order to check for the presence of early dead embryos which could not be determined by candling. The statistical significance of treatment differences in fertility and hatchability was estimated by analysis of variance. Fertility and hatchability were considered as traits of the hen so the error term was based on the variance between hens within treatments. The use of pooled semen should randomize the effect of males. Percentage values were converted to arcsine Vpercentage prior to analysis.
719
INSEMINATION AND FERTILITY TABLE 1.—Percent fertility obtained with the syringe, tube or rod methods, and weekly or bi-weekly inseminations Method 0f insem. Syringe Tube Rod Tube Rod
Freq. 0f insem. Weekly Weekly Weekly Bi-Weekly Bi-Weeklv
Weeks of lay 10-15
16-21
% Fertility 74(12/107) 76(39/743)' 86(17/199) 64(37/734) 66(16/187) 78(40/790) 65(41/812)
18-27
28-36
86 (18/625)" 68(17/572) 64(17/590) 56(17/626)
40(ll/280) 2 69(12/231) 39(10/265)
weeks). The syringe and rod methods gave similar fertility. There was no significant difference in hatchability of fertile eggs between treatments in any trial. The superiority of the tube method may have been due to several factors. Among these are: (1) prevention of spread of infectious organisms by this method; (2) oxygenation of the semen by the use of the tube method; and (3) fewer hens being completely infertile with the tube method because of presence of semen on the outside of the tube as well as being blown in the oviduct with more force resulting in a wider distribution of the semen in the oviduct. In order to determine whether the first of the above possible explanations was a factor in higher fertility obtained with the tube method, one group of 64 hens was inseminated using a common tube for all hens and a similar group was inseminated with a clean tube for each hen. Weekly inseminations were made over a twelve-week period. There was no significant difference in fertility and hatchability (Table 2). This indicates that something other than prevention of spread of infectious organisms was responsible for the superiority of the tube method. This agrees with the results of Ogasawara and Rooney (1966) who found that treatments of hens with an-
tibiotics in a low fertility flock did not increase fertility. They postulated that the low fertility of this flock was the result of insufficient numbers of spermatozoa being inseminated rather than from a reaction to an unidentified pathogenic agent. Aeration of semen at the time of insemination may have resulted in the increased fertility obtained with the tube method. However, Harper (1965) found that aeration of semen for IS, 60 and 120 minutes following collection did not affect the fertilizing capacity of spermatozoa. Schindler and Nevo (1962) found that, depending on dilution, cock spermatozoa became inactive after a period of from 2 to 30 minutes due to lack of ozygen. Thus it is possible that Harper's aerated samples became inactive, or largely so, after aeration was discontinued before insemination and therefore did not differ from non-aerated samples in motility. Since turkey semen is more concentrated than cock semen, the inactivation of turkey spermatozoa as the result of lack of
TABLE 2.—The effect of using a common tube for all hens
Common Tube Tubes Changed
2,057 1,992
87.3 88.4
63.2 67.6
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
1 Numbers in parenthesis refer to number of hens/numbers of eggs on which the fertility averages were based. 2 Differences between methods were significant (P<.01). 3 Differences between frequency of insemination were significant (P<.05).
720
K. E. NESTOR AND K. I. BROWN TABLE 3.—Fertility of eggs according to days following insemination Days after insemination 2
No. Eggs 513 Percent Fertility 69
3
4
5
6
7
8
499 71
445 70
542 66
543 64
508 65
527 61
SUMMARY
The tube method of insemination resulted in consistently higher fertility than either the glass rod or syringe methods. The use of a common tube for all hens or a clean tube for each hen gave similar fertility, suggesting that prevention of spread of infectious organisms was not a factor in the superiority of the tube method. The syringe and rod methods of insemination gave similar fertility. Method of insemina-
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
oxygen would proceed at a more rapid rate. Inactivated cock spermatozoa can be reactivated by addition of oxygen (Schindler and Nevo, 1962). The oxygenation occurring with insemination by the tube method could have increased the motility at the time when motility is probably most important in fertilization and thus increased fertility. The spreading of semen over a larger area of the vagina due to the pressure involved in blowing the semen into the oviduct could also have been an important factor in the higher fertility obtained with the tube method. This, along with the semen adhering to the outside of the tube, probably reduced the chance of hens being completely infertile as the result of inadequate numbers of spermatozoa. The volume of semen on the outside of the tube was probably as great as the volume inseminated with the rod method. Weekly inseminations resulted in higher fertility (P < .05) than bi-weekly inseminations in a fertility trial conducted during the 18th to 27th weeks of lay (Table 1). Such a difference was not evident during the 10th to 15th weeks of lay. This indicates that frequency of insemination is more important late in the laying season. The fertility obtained with weekly inseminations later in the laying period (18 to 27 weeks) was actually slightly higher than corresponding fertility obtained earlier (19 to 15 weeks). However, inseminations every two weeks were not capable of maintaining the same level of fertility. The difference in results obtained with frequency of insemination between the ear-
lier work and more recent experiments may be explained by a difference in body weight of the strains involved since large gains in body weight have been made by commercial turkey breeders in the last 10 to 12 years. Ogasawara et al. (1963) found a negative genetic correlation between body weight during the growing season and level of fertility as well as the ability to maintain fertility following insemination. The question arose whether inseminating more frequently than once a week might increase fertility late in the laying season. To answer this, data were collected on the fertility obtained in eggs laid from 2 through 8 days following insemination. Due to time involved in egg formation, eggs are not normally fertilized until the second day following insemination. Thus, the second day following insemination would represent the first day in which eggs were fertilized by that insemination. Data collected on 216 hens over a nineweek period (during the 18th to 26th weeks of production) are presented in Table 3. Fertility reached a peak three days after insemination and then declined. The fertility of eggs laid eight days after insemination was ten percent less than that obtained on the third day following insemination. These results suggest that insemination more frequently than once per week would improve fertility late in the season.
INSEMINATION AND FERTILITY
REFERENCES Bajpai, P. K., and K. I. Brown, 1964. Observations on turkey fertility. Ohio Report, 49: 76-77. Burrows, W. H., and S. J. Marsden, 1938. Artificial breeding of turkeys. Poultry Sci. 17: 408-411. Harper, J. A., 1965. Fertility of turkey eggs as related to method of collecting and aeration of semen. Poultry Sci. 44: 726-731.
McCartney, M. G., 1952. The physiology of reproduction in turkeys. 3. Effect of frequency of mating and semen dosage on fertility and hatchability. Poultry Sci. 3 1 : 878-881. McCartney, M. G., 1954. The physiology of reproduction in turkeys. 4. Relation of frequency of mating and semen dosage to reproductive performance. Poultry Sci. 3 3 : 390-391. McCartney, M. G., 1964. A randombred control population of turkeys. Poultry Sci. 4 3 : 739-744. Nestor, K. E., and K. I. Brown, 1966. Method and frequency of artificial insemination influence turkey fertility. Ohio Report, SO: 74. Ogasawara, F. X., and W. F. Rooney, 1966. Artificial insemination and fertility in turkeys. British Poultry Sci. 7: 77-82. Ogasawara, F. X., H. Abplanalp and V. S. Asmundson, 1963. Effect of selection for body weight and reproduction in turkey hens. Poultry Sci. 42: 838-842. Schindler, H., and A. Nevo, 1962. Reversible inactivation and agglutination of fowl and bull spermatozoa under anaerobic conditions. J. Reprod. Fertil. 4 : 251-265.
Genotype-Environment Interactions in Broiler Stocks of Chickens 2. STOCK BY LOCATION, STOCK BY FLOOR SPACE AND STOCK BY TRIAL INTERACTIONS 1 L. D. TINDELL, 2 " 3 C. H. MOORE,4 N. R. GYLES,5 W. A. JOHNSON, 6 L. J. DREESEN, 7 G. A. MARTIN 8 AND P. B. SIEGEL9 Agricultural Experiment Stations of the Southern Region2-" and United States Department of Agriculture (Received for publication July 26, 1967)
P
REVIOUS studies with broilers have indicated that interactions of stock with rearing location are of minor practical 1
This investigation was conducted as part of the Southern Regional Poultry Breeding Project (S-57), a cooperative study involving agricultural experiment stations in the Southern Region and supported in part by Regional Research Funds and Poultry Research Branch Funds of the United States Department of Agriculture. University of Georgia, College of Agriculture Experiment Stations, Journal Paper number 104, College Station, Athens.
importance for body weight and other broiler traits (Gutteridge and O'Neil, 1942; Merritt and Gowe, 1956; Lewis and Blow, 1965). Significant (P < .05) or highly significant (P < .01) interactions 2 Coordinator, Southern Regional Poultry Breeding Project, AHRD, ARS, USDA, Athens, Georgia. 3-8 Technical Committee Members (S-57) from the Agricultural Experiment Stations located in Georgia, Alabama, Arkansas, Louisiana, Mississippi, North Carolina and Virginia, respectively.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
tion had no influence on hatchability of fertile eggs. More frequent inseminations resulted in higher fertility late in the laying season. There was no significant difference in fertility obtained between weekly and bi-weekly insemination when data were collected from the tenth to fifteenth weeks of lay. A significantly higher level of fertility was obtained with weekly inseminations from the 18th to 27th weeks of lay.
721
BODY TEMPERATURE
No special technique was used to revive the birds in either of the experiments. After removal from the cold chamber, the birds were placed in the pen with the controls.
REFERENCES Moreng, R. E., and C. S. Shaffner, 1951. Lethal internal temperatures for the chicken from fertile egg to mature bird. Poultry Sci. 30: 255-266. Reece, F. N., and J. W. Deaton, 1968. A radio transmitter for telemetering body temperatures of chickens. Poultry Sci. 47: 424-428.
Method and Frequency of Artificial Insemination and Turkey Fertility KARL E. NESTOR AND KEITH I. BROWN Ohio Agricultural Research and Development Center, Wooster, Ohio 44691 (Received for publication July 19, 1967)
L
OW fertility is still a serious problem ' in producing turkey hatching eggs even though most turkeys are artificially inseminated. Generally, the fertility of turkey eggs is relatively high at the beginning of the breeding season and then declines as the season progresses. Several factors may be responsible for the seasonal decline in fertility. Among these are faulty insemination techniques, as shown by Ogasawara and Rooney (1966), and mechanical spread of infectious organisms from hen to hen by the insemination technique. Many turkey breeders and turkey hatching egg producers are now using a disposable plastic tube for insemination in order to prevent spread of vaginal infection. Although the use of the tube method of insemination has become an established practice commercially, there has been little experimental evidence to show that it is a su-
perior method. In a preliminary report of the present work, Nestor and Brown (1966) observed that the tube method of insemination gave higher fertility than the syringe method. Bajpai and Brown (1964) compared the syringe and rod methods of insemination. Fertility obtained with the two methods of insemination was identical. Burrows and Marsden (1938) inseminated turkeys repeatedly at intervals of 1, 2, 3, and 4 weeks and found no apparent tendency for fertility to decline with increasing length of interval between successive inseminations. McCartney (1952) found that increasing the insemination interval from 2 to 4 weeks resulted in a highly significant decrease in fertility, but in a later study (1954) observed no significant difference in fertility between intervals of 2 and 3 weeks. More recent work (Bajpai and Brown, 1964; Nestor and Brown, 1966; and Ogasawara and Rooney,
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
SUMMARY A telemetry technique was used to monitor the body temperature of broiler chicks. Altering body temperature of broilers at 1, 8, 15, and 22 days of age to an average of 24.4°, 26.0°, 33.1°, and 39.6°C, respectively, had no significant effect on 8-week body weight, mortality or condemnation when compared to the controls. Subjecting
female broiler chicks at 1 and 7 days of age to an ambient temperature of — 3.9°C. until all birds became comatose had no significant effect on 8-week body weight, mortality, or condemnation.
718
K. E. NESTOR AND K. I. BROWN
1966) indicates that fertility is increased by weekly inseminations in comparison to bi-weekly inseminations, especially late in the laying season. The purpose of this experiment was to determine the influence of method and frequency of insemination on turkey fertility. MATERIALS AND METHODS
RESULTS AND DISCUSSION
The percent fertility obtained with various treatments is summarized in Table 1. Fertility obtained by the use of the tube method was consistently higher than that obtained with the other two methods. However, the differences among methods of insemination were significant (P < .05) only in comparisons made very late in the laying season (18 to 27 weeks and 28 to 36
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
The methods of insemination compared in this experiment were the syringe, tube, and glass rod. Semen was inseminated by means of a 0.25 cc. glass syringe (B.D. Yale with glass Luer tip) with the syringe method. The tube method of insemination used in this experiment consisted of attaching a rigid plastic tube (5 mm. X .4 cc. X 10.16 cm.) to a section of plastic tubing, dipping the tube into semen, and blowing the semen into the oviduct by mouth. A different tube was used for each hen. The tubes were washed and re-used. They were washed in water containing detergent and then allowed to soak in a 95% ethyl alcohol solution for at least one day. After soaking, they were dried and re-used. The glass rod method was similar to the method described by Bajpai and Brown (1964). A common glass rod (approximately 3.0 mm. X 15 cm.) was used to inseminate all hens in a group in this study. A concave cup was formed on one end of the rod by heating. The end with the depression was dipped into the semen and then inserted in the oviduct and wiped clean. The syringe and rod methods would be conducive to spread of infectious organisms from hen to hen since repeated inseminations were made without sterilization. The posssibility was minimized with the tube method. The hens in all trials were from different flocks of a strain selected for and exhibiting high egg production. This strain was
initiated in 1960 from a randombred control population (McCartney, 1964) and has changed very little in body weight since that time. Most of the comparisons were made during hot weather late in the laying season when the fertility level is normally low. Pooled semen from 20 to 30 males was divided into aliquots. A different aliquot was used with each method of insemination. No effort was made to keep constant the amount of semen inseminated per hen with the different methods of insemination. However, an excessive amount of semen (in excess of 0.02 cc. per hen) was used with the tube and syringe methods of insemination. Semen was collected and held at 15°C. during insemination. Eggs were set at weekly intervals. They were candled on the seventh day of incubation. Eggs classified as infertiles were broken open and examined macroscopically in order to check for the presence of early dead embryos which could not be determined by candling. The statistical significance of treatment differences in fertility and hatchability was estimated by analysis of variance. Fertility and hatchability were considered as traits of the hen so the error term was based on the variance between hens within treatments. The use of pooled semen should randomize the effect of males. Percentage values were converted to arcsine Vpercentage prior to analysis.
719
INSEMINATION AND FERTILITY TABLE 1.—Percent fertility obtained with the syringe, tube or rod methods, and weekly or bi-weekly inseminations Method 0f insem. Syringe Tube Rod Tube Rod
Freq. 0f insem. Weekly Weekly Weekly Bi-Weekly Bi-Weeklv
Weeks of lay 10-15
16-21
% Fertility 74(12/107) 76(39/743)' 86(17/199) 64(37/734) 66(16/187) 78(40/790) 65(41/812)
18-27
28-36
86 (18/625)" 68(17/572) 64(17/590) 56(17/626)
40(ll/280) 2 69(12/231) 39(10/265)
weeks). The syringe and rod methods gave similar fertility. There was no significant difference in hatchability of fertile eggs between treatments in any trial. The superiority of the tube method may have been due to several factors. Among these are: (1) prevention of spread of infectious organisms by this method; (2) oxygenation of the semen by the use of the tube method; and (3) fewer hens being completely infertile with the tube method because of presence of semen on the outside of the tube as well as being blown in the oviduct with more force resulting in a wider distribution of the semen in the oviduct. In order to determine whether the first of the above possible explanations was a factor in higher fertility obtained with the tube method, one group of 64 hens was inseminated using a common tube for all hens and a similar group was inseminated with a clean tube for each hen. Weekly inseminations were made over a twelve-week period. There was no significant difference in fertility and hatchability (Table 2). This indicates that something other than prevention of spread of infectious organisms was responsible for the superiority of the tube method. This agrees with the results of Ogasawara and Rooney (1966) who found that treatments of hens with an-
tibiotics in a low fertility flock did not increase fertility. They postulated that the low fertility of this flock was the result of insufficient numbers of spermatozoa being inseminated rather than from a reaction to an unidentified pathogenic agent. Aeration of semen at the time of insemination may have resulted in the increased fertility obtained with the tube method. However, Harper (1965) found that aeration of semen for IS, 60 and 120 minutes following collection did not affect the fertilizing capacity of spermatozoa. Schindler and Nevo (1962) found that, depending on dilution, cock spermatozoa became inactive after a period of from 2 to 30 minutes due to lack of ozygen. Thus it is possible that Harper's aerated samples became inactive, or largely so, after aeration was discontinued before insemination and therefore did not differ from non-aerated samples in motility. Since turkey semen is more concentrated than cock semen, the inactivation of turkey spermatozoa as the result of lack of
TABLE 2.—The effect of using a common tube for all hens
Common Tube Tubes Changed
2,057 1,992
87.3 88.4
63.2 67.6
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
1 Numbers in parenthesis refer to number of hens/numbers of eggs on which the fertility averages were based. 2 Differences between methods were significant (P<.01). 3 Differences between frequency of insemination were significant (P<.05).
720
K. E. NESTOR AND K. I. BROWN TABLE 3.—Fertility of eggs according to days following insemination Days after insemination 2
No. Eggs 513 Percent Fertility 69
3
4
5
6
7
8
499 71
445 70
542 66
543 64
508 65
527 61
SUMMARY
The tube method of insemination resulted in consistently higher fertility than either the glass rod or syringe methods. The use of a common tube for all hens or a clean tube for each hen gave similar fertility, suggesting that prevention of spread of infectious organisms was not a factor in the superiority of the tube method. The syringe and rod methods of insemination gave similar fertility. Method of insemina-
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
oxygen would proceed at a more rapid rate. Inactivated cock spermatozoa can be reactivated by addition of oxygen (Schindler and Nevo, 1962). The oxygenation occurring with insemination by the tube method could have increased the motility at the time when motility is probably most important in fertilization and thus increased fertility. The spreading of semen over a larger area of the vagina due to the pressure involved in blowing the semen into the oviduct could also have been an important factor in the higher fertility obtained with the tube method. This, along with the semen adhering to the outside of the tube, probably reduced the chance of hens being completely infertile as the result of inadequate numbers of spermatozoa. The volume of semen on the outside of the tube was probably as great as the volume inseminated with the rod method. Weekly inseminations resulted in higher fertility (P < .05) than bi-weekly inseminations in a fertility trial conducted during the 18th to 27th weeks of lay (Table 1). Such a difference was not evident during the 10th to 15th weeks of lay. This indicates that frequency of insemination is more important late in the laying season. The fertility obtained with weekly inseminations later in the laying period (18 to 27 weeks) was actually slightly higher than corresponding fertility obtained earlier (19 to 15 weeks). However, inseminations every two weeks were not capable of maintaining the same level of fertility. The difference in results obtained with frequency of insemination between the ear-
lier work and more recent experiments may be explained by a difference in body weight of the strains involved since large gains in body weight have been made by commercial turkey breeders in the last 10 to 12 years. Ogasawara et al. (1963) found a negative genetic correlation between body weight during the growing season and level of fertility as well as the ability to maintain fertility following insemination. The question arose whether inseminating more frequently than once a week might increase fertility late in the laying season. To answer this, data were collected on the fertility obtained in eggs laid from 2 through 8 days following insemination. Due to time involved in egg formation, eggs are not normally fertilized until the second day following insemination. Thus, the second day following insemination would represent the first day in which eggs were fertilized by that insemination. Data collected on 216 hens over a nineweek period (during the 18th to 26th weeks of production) are presented in Table 3. Fertility reached a peak three days after insemination and then declined. The fertility of eggs laid eight days after insemination was ten percent less than that obtained on the third day following insemination. These results suggest that insemination more frequently than once per week would improve fertility late in the season.
INSEMINATION AND FERTILITY
REFERENCES Bajpai, P. K., and K. I. Brown, 1964. Observations on turkey fertility. Ohio Report, 49: 76-77. Burrows, W. H., and S. J. Marsden, 1938. Artificial breeding of turkeys. Poultry Sci. 17: 408-411. Harper, J. A., 1965. Fertility of turkey eggs as related to method of collecting and aeration of semen. Poultry Sci. 44: 726-731.
McCartney, M. G., 1952. The physiology of reproduction in turkeys. 3. Effect of frequency of mating and semen dosage on fertility and hatchability. Poultry Sci. 3 1 : 878-881. McCartney, M. G., 1954. The physiology of reproduction in turkeys. 4. Relation of frequency of mating and semen dosage to reproductive performance. Poultry Sci. 3 3 : 390-391. McCartney, M. G., 1964. A randombred control population of turkeys. Poultry Sci. 4 3 : 739-744. Nestor, K. E., and K. I. Brown, 1966. Method and frequency of artificial insemination influence turkey fertility. Ohio Report, SO: 74. Ogasawara, F. X., and W. F. Rooney, 1966. Artificial insemination and fertility in turkeys. British Poultry Sci. 7: 77-82. Ogasawara, F. X., H. Abplanalp and V. S. Asmundson, 1963. Effect of selection for body weight and reproduction in turkey hens. Poultry Sci. 42: 838-842. Schindler, H., and A. Nevo, 1962. Reversible inactivation and agglutination of fowl and bull spermatozoa under anaerobic conditions. J. Reprod. Fertil. 4 : 251-265.
Genotype-Environment Interactions in Broiler Stocks of Chickens 2. STOCK BY LOCATION, STOCK BY FLOOR SPACE AND STOCK BY TRIAL INTERACTIONS 1 L. D. TINDELL, 2 " 3 C. H. MOORE,4 N. R. GYLES,5 W. A. JOHNSON, 6 L. J. DREESEN, 7 G. A. MARTIN 8 AND P. B. SIEGEL9 Agricultural Experiment Stations of the Southern Region2-" and United States Department of Agriculture (Received for publication July 26, 1967)
P
REVIOUS studies with broilers have indicated that interactions of stock with rearing location are of minor practical 1
This investigation was conducted as part of the Southern Regional Poultry Breeding Project (S-57), a cooperative study involving agricultural experiment stations in the Southern Region and supported in part by Regional Research Funds and Poultry Research Branch Funds of the United States Department of Agriculture. University of Georgia, College of Agriculture Experiment Stations, Journal Paper number 104, College Station, Athens.
importance for body weight and other broiler traits (Gutteridge and O'Neil, 1942; Merritt and Gowe, 1956; Lewis and Blow, 1965). Significant (P < .05) or highly significant (P < .01) interactions 2 Coordinator, Southern Regional Poultry Breeding Project, AHRD, ARS, USDA, Athens, Georgia. 3-8 Technical Committee Members (S-57) from the Agricultural Experiment Stations located in Georgia, Alabama, Arkansas, Louisiana, Mississippi, North Carolina and Virginia, respectively.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on June 22, 2015
tion had no influence on hatchability of fertile eggs. More frequent inseminations resulted in higher fertility late in the laying season. There was no significant difference in fertility obtained between weekly and bi-weekly insemination when data were collected from the tenth to fifteenth weeks of lay. A significantly higher level of fertility was obtained with weekly inseminations from the 18th to 27th weeks of lay.
721