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Changes in Feed Consumption and Gross Feed Efficiency of Lines Selected for Part-Record Egg Production
Changes in Feed Consumption and Gross Feed Efficiency of Lines Selected for Part-Record Egg Production R.
FRANKHAM1
Canada Department of Agriculture, Research Station, Lacombe, Alberta, Canada (Received for publication January 14, 1971)
A
brooder until 35 days of age, reared in 36 X 41 cm. wire cages (5 birds per cage) and then placed in individual 18 X 41 cm. cages at 106 days of age. There were 119, 119 and 118 birds from S27S, S% and OCS, respectively at this stage. These birds were allocated to 10 groups (of 11 or 12 birds) per strain and the groups allocated at random within the laying house. For each group, feed consumption was recorded weekly and egg mass daily from 106 to 4SS days of age. Feed consumption was also recorded prior to 106 days of age. Feed and water were provided on an ad libitum basis. The birds were provided with starter mash for the first 35 days of life, Ottawa rearing mash (Table 1) from 36 to 161 days of age and Ottawa hatching pellets (Table 1) from 162 to 455 days of age. Differences between strain means were tested using the t test.
MATERIALS AND METHODS
RESULTS
S275 and S% are two lines of White Leghorns selected for increased part-record egg production under floor housing. OCS is their unselected base population (control). Their origin, management and production were described by Frankham and Doornenbal(1970). The birds used in this experiment were produced in a single hatch and reared with the strains separated into groups which were allocated at random within the facilities. They were brooded in a battery
Data for egg mass, feed consumption and gross feed efficiency for the three strains are summarized in Table 2. Both selected strains (S275 and S%) produced significantly greater egg mass than the control (OCS). S275 produced significantly more egg mass than S%. These differences are of a similar order to those found for floor housing conditions (Frankham and Doornenbal, 1970). Feed consumption (106 to 455 days) was significantly less in S275 than OCS while S% did not differ from OCS. Total feed consumption (0 to 455 days) showed a similar pattern with the deviations from control for the selected lines
1 Present address: School of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia.
1194
Downloaded from http://ps.oxfordjournals.org/ at Simon Fraser University on June 14, 2015
GENETIC increase in egg production produced by selection must be accompanied by either an improvement in the gross efficiency of conversion of feed to eggs (g. feed/g. eggs, hereafter termed gross feed efficiency) and/or an increase in feed consumption. For selection for egg production to be of economic value it must lead to an improvement in the former (i.e. gross feed efficiency). However, no evaluation of the effects of selection for egg production on feed consumption and feed efficiency has been reported, nor are reports of genetic parameters available to predict the outcome of such experiments. The objectives of this study were to compare the feed consumption and gross feed efficiency of two lines of White Leghorns selected for increased part-record egg production with those of their unselected base population.
1195
EFFICIENCY OF EGG PRODUCTION
TABLE 1.—Constituents of the rations used and the calculated nutrient levels
Constituent
Ottawa hatching ration
Percentage composition Ground wheat 41.5 Ground corn 10.0 Ground oats 20.0 Ground barley 10.0 Stabilized tallow 2.0 Fish meal (65% protein) 2.0 M e a t meal (50% protein) 2.0 Soybean meal (44% protein) 5.0 Skim-milk powder 1.5 Dehydrated cereal grass 1.5 Dehydrated alfalfa meal 1.5 Steamed bone meal 1.25 Ground limestone 1.25 Iodized salt 0.38 Dried whey Dicalcium phosphate Vitamin A (I.U./g.) 10.8 Vitamin D (I.C.U./g.) 1.52 Riboflavin (mg./kg.) 6.9 Manganese sulphate (mg./kg.) 125.0
Ottawa rearing ration 37.0 5.0 27.5 15.0 2.0 2.0 7.5 1.5 0.63 0.25 1.0 0.5 6.7 0.38 4.3 125.0 "
Calculated analysis Crude protein (%) Metabolisable energy (kcal./g.) Calcium (%) Phosphorus (%)
15.8 1.97 1.3 0.7
15.6 1.90 0.7 0.6
TABLE 2.—Egg mass, feed consumption, gross feed efficiency and body weight for the three strains Strain OCS
S275
S%
Egg mass (kg./bird) Total (0-455days) Total (0-455 days) 106-455 days
9.03+.16' 11.08+.23" 10.42+.27**$ Feed consumption (kg./bird) 42.80 41.02 42.46 37.47±.51 36.03+.44* 37.27+.51 Gross feed efficiency (g. feed/g. egg)
Total (0-455 days) 106-455days Part-record (197-273 days) Residual-record (274-455 days)
4.74 4.09+.13
3.70 3.26+.07**
4.07 3.59±.07**t
3.28+. 08
2.74+.08**
2.84+.05**
3.74+.09
3.07+.07**
3.39+.09*t
Body weights (g.) at 343 days of age 2064+.26 1851 + 20** 1876±23** 1 Standard errors. * and **, P <.05 and P <.01, respectively, for comparison with OCS. % P <.01 for comparison between S275 and S%.
residual-records (0.54 and 0.67 for S275, and 0.44 and 0.35 for S%, respectively). DISCUSSION Increases in egg production of the selected lines were associated with improved gross feed efficiency. Feed consumption also changed in one line but in a direction indicating a decrease in feed consumption with a genetic increase in production. It should be noted that gross feed efficiency as defined (g. feed/g. eggs) includes the feed used for maintenance. This measure of gross feed efficiency was used as it is the one of most interest in commercial operations. These results indicate a high positive genetic correlation between egg production and gross feed efficiency and a small (perhaps zero) genetic correlation between egg production and feed consumption. Thus, selection for egg production would appear to be a highly effective means for increasing the gross efficiency of conversion of feed to eggs. The absence of the relevant genetic parameters precludes an estimation of the relative efficiency of direct selection for gross feed efficiency versus selection for
Downloaded from http://ps.oxfordjournals.org/ at Simon Fraser University on June 14, 2015
being greater. Standard errors could not be estimated for total feed consumption (or total gross feed efficiency) as the birds were in different groups prior to 106 days of age. Gross feed efficiency (106 to 455 days) was significantly better in the selected lines than the control and significantly better in S275 than S%. Lifetime gross feed efficiency (0 to 455 days) showed a similar pattern with the deviations from control for the selected lines being greater. Since the selection lines were selected for part-record egg production, it is of interest to compare gross feed efficiency in both the part-record and the residual record to determine whether changes in the two periods were similar. For this purpose the part-record gross feed efficiency was taken as that for the period 197 to 273 days of age so that the strain comparisons would not be affected by their different ages at first egg. Expressed as a deviation from control, the improvement in gross feed efficiency in the selected strains was similar in the part- and
1196
R. FEANKHAM
SUMMARY
Feed consumption and gross feed effi-
ciency (g. feed per g. eggs) of two lines selected for increased part-record egg production were compared with those of their unselected base population. There was a large improvement in gross feed efficiency in the selected lines. The only change in feed consumption was a slight reduction in one of the selected lines. Thus, the genetic correlation between egg production and gross feed efficiency appears to be high and negative. Selection for egg production appears to be a highly effective means for improving gross feed efficiency. ACKNOWLEDGMENTS
The author is grateful to I. Friesen, W. E. Sage, A. W. Wilson and A. S. Schonheiter for their assistance in carrying out these experiments, to Mrs. E. Reimer for assistance in the analyses and to H. Doornenbal, H. T. Fredeen and J. G. Stothart for their comments on the manuscript. REFERENCES Brody, S., 1945. Bioenergetics and Growth. Reinhold Publishing Corp., N.Y., Chpt. 23. Doornenbal, H., R. Frankham and G. M. Weiss, 1970. Physiological differences associated with genetic differences in egg production. 2. Gross chemical composition of the body. Poultry Sci. 49: 1615-1618. Frankham, R., and H. Doornenbal, 1970. Physiological differences associated with genetic differences in egg production. 1. Organ and endocrine gland weights. Poultry Sci. 49: 1610-1615.
NEWS AND NOTES (Continued jrom page 1193) A.P.H.F. SCHOLARSHIP in the Atlantic Provinces who is majoring in animal science with a specific interest in poultry." At the annual meeting of the Atlantic Provinces Hatchery Federation, held in Amherst, Nova ScoU.C.O. NOTES tia, Canada, Adrianus de Graaf, R.R. # 2 , Port Williams, Nova Scotia, was presented with the Robert A. Costain has been appointed Manager A.P.H.F. Scholarship of $200.00 by Stuart Allaby, of Feed Research for the United Co-operatives of Provincial Poultry Superintendent of Nova Scotia. Ontario. He received a B.Sc. degree, specializing in This Scholarship is an annual award "to a student animal husbandry, and a Ph.D., specializing in ani(Continued on page 1205)
Downloaded from http://ps.oxfordjournals.org/ at Simon Fraser University on June 14, 2015
egg production as a means for improving gross feed efficiency. However, the practical difficulties of measuring feed efficiency are at present sufficient to discourage direct selection for that trait. The most likely means by which this increase in gross feed efficiency would be achieved are, (a) improved ability to digest nutrients, (b) more efficient nutrient metabolism, (c) lowered body maintenance requirements, or (d) reallocation of nutrients from body functions, body storage or other activities to egg production. No evidence is available pertaining to (a) and (b), but (c) and (d) have probably contributed to the improved gross feed efficiency in the selection lines. Maintenance requirements are probably lower in the selected lines than the control since the selected line birds have smaller body weights (see Table 2) and body weight and maintenance requirements (especially for energy) are closely related (Brody, 1945). The selected strain birds have a lower percentage body fat than the control (Doornenbal et al., 1970) so it appears that there has been a reallocation of nutrients from body reserves to egg production. More information on the means by which the improvements in gross feed efficiency have been achieved would be of interest.
FRANKHAM1
Canada Department of Agriculture, Research Station, Lacombe, Alberta, Canada (Received for publication January 14, 1971)
A
brooder until 35 days of age, reared in 36 X 41 cm. wire cages (5 birds per cage) and then placed in individual 18 X 41 cm. cages at 106 days of age. There were 119, 119 and 118 birds from S27S, S% and OCS, respectively at this stage. These birds were allocated to 10 groups (of 11 or 12 birds) per strain and the groups allocated at random within the laying house. For each group, feed consumption was recorded weekly and egg mass daily from 106 to 4SS days of age. Feed consumption was also recorded prior to 106 days of age. Feed and water were provided on an ad libitum basis. The birds were provided with starter mash for the first 35 days of life, Ottawa rearing mash (Table 1) from 36 to 161 days of age and Ottawa hatching pellets (Table 1) from 162 to 455 days of age. Differences between strain means were tested using the t test.
MATERIALS AND METHODS
RESULTS
S275 and S% are two lines of White Leghorns selected for increased part-record egg production under floor housing. OCS is their unselected base population (control). Their origin, management and production were described by Frankham and Doornenbal(1970). The birds used in this experiment were produced in a single hatch and reared with the strains separated into groups which were allocated at random within the facilities. They were brooded in a battery
Data for egg mass, feed consumption and gross feed efficiency for the three strains are summarized in Table 2. Both selected strains (S275 and S%) produced significantly greater egg mass than the control (OCS). S275 produced significantly more egg mass than S%. These differences are of a similar order to those found for floor housing conditions (Frankham and Doornenbal, 1970). Feed consumption (106 to 455 days) was significantly less in S275 than OCS while S% did not differ from OCS. Total feed consumption (0 to 455 days) showed a similar pattern with the deviations from control for the selected lines
1 Present address: School of Biological Sciences, Macquarie University, North Ryde, NSW 2113, Australia.
1194
Downloaded from http://ps.oxfordjournals.org/ at Simon Fraser University on June 14, 2015
GENETIC increase in egg production produced by selection must be accompanied by either an improvement in the gross efficiency of conversion of feed to eggs (g. feed/g. eggs, hereafter termed gross feed efficiency) and/or an increase in feed consumption. For selection for egg production to be of economic value it must lead to an improvement in the former (i.e. gross feed efficiency). However, no evaluation of the effects of selection for egg production on feed consumption and feed efficiency has been reported, nor are reports of genetic parameters available to predict the outcome of such experiments. The objectives of this study were to compare the feed consumption and gross feed efficiency of two lines of White Leghorns selected for increased part-record egg production with those of their unselected base population.
1195
EFFICIENCY OF EGG PRODUCTION
TABLE 1.—Constituents of the rations used and the calculated nutrient levels
Constituent
Ottawa hatching ration
Percentage composition Ground wheat 41.5 Ground corn 10.0 Ground oats 20.0 Ground barley 10.0 Stabilized tallow 2.0 Fish meal (65% protein) 2.0 M e a t meal (50% protein) 2.0 Soybean meal (44% protein) 5.0 Skim-milk powder 1.5 Dehydrated cereal grass 1.5 Dehydrated alfalfa meal 1.5 Steamed bone meal 1.25 Ground limestone 1.25 Iodized salt 0.38 Dried whey Dicalcium phosphate Vitamin A (I.U./g.) 10.8 Vitamin D (I.C.U./g.) 1.52 Riboflavin (mg./kg.) 6.9 Manganese sulphate (mg./kg.) 125.0
Ottawa rearing ration 37.0 5.0 27.5 15.0 2.0 2.0 7.5 1.5 0.63 0.25 1.0 0.5 6.7 0.38 4.3 125.0 "
Calculated analysis Crude protein (%) Metabolisable energy (kcal./g.) Calcium (%) Phosphorus (%)
15.8 1.97 1.3 0.7
15.6 1.90 0.7 0.6
TABLE 2.—Egg mass, feed consumption, gross feed efficiency and body weight for the three strains Strain OCS
S275
S%
Egg mass (kg./bird) Total (0-455days) Total (0-455 days) 106-455 days
9.03+.16' 11.08+.23" 10.42+.27**$ Feed consumption (kg./bird) 42.80 41.02 42.46 37.47±.51 36.03+.44* 37.27+.51 Gross feed efficiency (g. feed/g. egg)
Total (0-455 days) 106-455days Part-record (197-273 days) Residual-record (274-455 days)
4.74 4.09+.13
3.70 3.26+.07**
4.07 3.59±.07**t
3.28+. 08
2.74+.08**
2.84+.05**
3.74+.09
3.07+.07**
3.39+.09*t
Body weights (g.) at 343 days of age 2064+.26 1851 + 20** 1876±23** 1 Standard errors. * and **, P <.05 and P <.01, respectively, for comparison with OCS. % P <.01 for comparison between S275 and S%.
residual-records (0.54 and 0.67 for S275, and 0.44 and 0.35 for S%, respectively). DISCUSSION Increases in egg production of the selected lines were associated with improved gross feed efficiency. Feed consumption also changed in one line but in a direction indicating a decrease in feed consumption with a genetic increase in production. It should be noted that gross feed efficiency as defined (g. feed/g. eggs) includes the feed used for maintenance. This measure of gross feed efficiency was used as it is the one of most interest in commercial operations. These results indicate a high positive genetic correlation between egg production and gross feed efficiency and a small (perhaps zero) genetic correlation between egg production and feed consumption. Thus, selection for egg production would appear to be a highly effective means for increasing the gross efficiency of conversion of feed to eggs. The absence of the relevant genetic parameters precludes an estimation of the relative efficiency of direct selection for gross feed efficiency versus selection for
Downloaded from http://ps.oxfordjournals.org/ at Simon Fraser University on June 14, 2015
being greater. Standard errors could not be estimated for total feed consumption (or total gross feed efficiency) as the birds were in different groups prior to 106 days of age. Gross feed efficiency (106 to 455 days) was significantly better in the selected lines than the control and significantly better in S275 than S%. Lifetime gross feed efficiency (0 to 455 days) showed a similar pattern with the deviations from control for the selected lines being greater. Since the selection lines were selected for part-record egg production, it is of interest to compare gross feed efficiency in both the part-record and the residual record to determine whether changes in the two periods were similar. For this purpose the part-record gross feed efficiency was taken as that for the period 197 to 273 days of age so that the strain comparisons would not be affected by their different ages at first egg. Expressed as a deviation from control, the improvement in gross feed efficiency in the selected strains was similar in the part- and
1196
R. FEANKHAM
SUMMARY
Feed consumption and gross feed effi-
ciency (g. feed per g. eggs) of two lines selected for increased part-record egg production were compared with those of their unselected base population. There was a large improvement in gross feed efficiency in the selected lines. The only change in feed consumption was a slight reduction in one of the selected lines. Thus, the genetic correlation between egg production and gross feed efficiency appears to be high and negative. Selection for egg production appears to be a highly effective means for improving gross feed efficiency. ACKNOWLEDGMENTS
The author is grateful to I. Friesen, W. E. Sage, A. W. Wilson and A. S. Schonheiter for their assistance in carrying out these experiments, to Mrs. E. Reimer for assistance in the analyses and to H. Doornenbal, H. T. Fredeen and J. G. Stothart for their comments on the manuscript. REFERENCES Brody, S., 1945. Bioenergetics and Growth. Reinhold Publishing Corp., N.Y., Chpt. 23. Doornenbal, H., R. Frankham and G. M. Weiss, 1970. Physiological differences associated with genetic differences in egg production. 2. Gross chemical composition of the body. Poultry Sci. 49: 1615-1618. Frankham, R., and H. Doornenbal, 1970. Physiological differences associated with genetic differences in egg production. 1. Organ and endocrine gland weights. Poultry Sci. 49: 1610-1615.
NEWS AND NOTES (Continued jrom page 1193) A.P.H.F. SCHOLARSHIP in the Atlantic Provinces who is majoring in animal science with a specific interest in poultry." At the annual meeting of the Atlantic Provinces Hatchery Federation, held in Amherst, Nova ScoU.C.O. NOTES tia, Canada, Adrianus de Graaf, R.R. # 2 , Port Williams, Nova Scotia, was presented with the Robert A. Costain has been appointed Manager A.P.H.F. Scholarship of $200.00 by Stuart Allaby, of Feed Research for the United Co-operatives of Provincial Poultry Superintendent of Nova Scotia. Ontario. He received a B.Sc. degree, specializing in This Scholarship is an annual award "to a student animal husbandry, and a Ph.D., specializing in ani(Continued on page 1205)
Downloaded from http://ps.oxfordjournals.org/ at Simon Fraser University on June 14, 2015
egg production as a means for improving gross feed efficiency. However, the practical difficulties of measuring feed efficiency are at present sufficient to discourage direct selection for that trait. The most likely means by which this increase in gross feed efficiency would be achieved are, (a) improved ability to digest nutrients, (b) more efficient nutrient metabolism, (c) lowered body maintenance requirements, or (d) reallocation of nutrients from body functions, body storage or other activities to egg production. No evidence is available pertaining to (a) and (b), but (c) and (d) have probably contributed to the improved gross feed efficiency in the selection lines. Maintenance requirements are probably lower in the selected lines than the control since the selected line birds have smaller body weights (see Table 2) and body weight and maintenance requirements (especially for energy) are closely related (Brody, 1945). The selected strain birds have a lower percentage body fat than the control (Doornenbal et al., 1970) so it appears that there has been a reallocation of nutrients from body reserves to egg production. More information on the means by which the improvements in gross feed efficiency have been achieved would be of interest.