- Email: [email protected]
Proposed Measure of Performance Efficiency in Laying Hens1
22
W. D. TERMOHLEN
dents to serve in every phase of the industry, with both production and marketing extension specialists, and carrying on both applied and fundamental research, and working cooperatively and in a well-coordinated manner with all other colleges and the United States Department of Agriculture; poultry people of the World working together with common understanding and for the good of the industry through the World's Poultry Industries Council— Again the light in the crystal ball fades briefly and then brightens with a closing message—You have just seen the highlights of the modern poultry industry, one of the most outstanding of our agricultural industries producing among the very top nutritional and necessary foods for mankind; namely, eggs and poultry meat, stabilized and beneficially profitable because its leadership has kept its obligation to the public constantly in mind through its program of economy of production, economy of marketing, quality of product, and merchandising to meet the demand pattern of the times. That, my friends, is what comes from being a historiographer.
Proposed Measure of Performance Efficiency in Laying Hens 1 WALTER MORGAN AND C. W. CARLSON South Dakota State University, Brookings, South Dakota 57006 (Received for publication May 8, 1967)
F
OR many years, percent production was regarded as a most useful criterion in appraising the value of laying hens. Although it remains as one of the best 1
Approved for publication by the Director of the South Dakota Experiment Station as paper 770 of the Journal Series.
efficiency indicators, measures of additional factors such as egg weight, egg quality, body weight and feed consumption have been utilized in the sophistication of productive analyses (Kleiber, 1965). With the development of commercial laying stocks which routinely attain the desired 57 gram
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
cent in poultry and egg dishes and uses; from the county shows, the winners compete in state shows, and the state winners at the National Annual Poultry Congress. The National Annual Poultry Congress—this is the big poultry event of the year and is held under the auspices of the American Poultry Industries Council which is an organization bringing together all local, state, regional and national poultry groups on a delegate basis. This event is held each year at the National Poultry Industry Center, an industry-owned, financed and endowed institution where there is located a huge exhibition hall with permanent exhibits showing the history of the industry and with the offices of the American Poultry Industries Council; poultry journals have become even more important and are not only general in nature, but specialized; the Poultry and Egg National Board with greatly extended activities and regional offices serving all areas of the country; a National Poultry and Egg Quality Merchandising Plan operated for the marketing end of the business along basic principles similar to the greatly extended National Poultry Improvement Plan; every Land-Grant College with a Poultry Industry Department training stu-
PERFORMANCE EFFICIENCY
23
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
egg weight, the measure of feed efficiency quality. The following formula considers has, for the past decade, concerned itself hen-size, egg-size, feed consumed and perwith the relationship of feed consumed to cent production in determining a unit value eggs produced (Ewing, 1963; Card and of performance efficiency index (PEI). The Nesheim, 1966). This has been a conve- PEI value may be used for comparative nient partial measure of performance ef- purposes between flocks or between indificiency. It is simple to use feed efficiency viduals. values for the calculation of profit, as they relate to cost of feed and to egg price, but PEI = F with the inverse relationship between high efficiency and numerical values for feed efK == 30EW -e- BW ficiency, an unnecessary barrier to underEW == average egg weight standing exists. BW == body weight of laying hen With all due respect to the usefulness of the determination of feed efficiency upon P == percent production these bases, there have been people, both in F == feed consumed per day. industry (Faulkner, 1965) and in academic circles (Quisenberry, 1965), who have How does the proposed formula differ strongly advocated that egg size should from presently used calculations for feed efhave been included in the calculations. In ficiency in laying flocks? A basic difference truth, feed efficiency values for flocks is that metric measure is used throughout. which produce undersized eggs are invalid, Use of the metric system has been mandaand the values for flocks which produce ov- tory within the Poultry Science Association ersized eggs do not recognize the economic since 1964, and has been recommended by advantage of the larger eggs. For many most scientific organizations (Frost, 1965; years the standard egg laying contests used and Wolfle, 1965). Present-day determinaa point-system which weighted egg-size as a tions of feed efficiency are basically of two productive factor (Council of American kinds. The first is in terms of kilograms (or Poultry Tests, 1958). A standard compari- pounds) of feed required to produce a son which has been successfully employed dozen eggs. In the aforementioned consideris one that defines feed efficiency as the ation, that would be comparable to 12F-4pounds of feed required to produce a dozen P if we disregard egg weight and body "24 ounce" eggs. Random Sample Tests weight. The second is in terms of kilograms currently report feed efficiency in terms of of feed per kilogram of eggs (or pounds of pounds of feed required to produce a pound feed per pound of eggs), which is of eggs (Agricultural Research Service, F-=- (EW) P. It then becomes obvious that 1966). The incorporation of body weight in the key difference in the newly proposed consideration of this efficiency measure has formula for PEI is "K". How does K imonly briefly been considered (Morgan and prove our determination of performance efCarlson, 1965). ficiency and what is a desirable K value? A useful value for those who are interStudies at this station have indicated that ested in selective efficiency for laying flocks eggs from year-old hens are equal to apmust consider rate of lay (percent produc- proximately one-thirtieth of their body tion), egg size and feed consumed. Other weight. That is, in 30 days a hen which lays considerations which might be considered daily will have laid the equivalent of her pertinent by some are body weight and egg body weight. Data pertinent to the K value
24
W. MORGAN AND C. W. CARLSON
TABLE 1.—Interrelationships of egg weight, body weight and K values for eleven inbred lines of White Leghorns BW (gm.)
K
2 5 3 1 4 10 8 6 12 9 11
53 53 57 52 57 55 55 54 52 57 54
1,785 1,790 1,800 1,600 1,720 1,645 1,630 1,580 1,470 1,606 1,470
0.89 0.89 0.95 0.98 0.99 1.00 1.01 1.02 1.06 1.07 1.10
Avge.
54
1,625
1.00
determination are presented in Table 1. Values range from 0.89 to 1.10, with a population mean value of 1.00, for the lines that are represented. The unweighted averages of 54 gm. and 1625 gm. are smaller than occur in most non-inbred populations. The population value for K is actually 0.9996 or approximately one. When collecting data at this station, we normally use a gram scale to weigh a group of three eggs from each hen. Multiplying this weight by 10 merely necessitates adding a zero. Hence, the relationship between the weight of 30 of her eggs and her body weight in grams can be immediately evaluated by inspection. If 30 eggs weigh more than the hen, the K value will be above one. This is desirable. Contrariwise, if the hen weighs more than the calculated weight of 30 eggs, the K value is below one. An examination of the import of K = 1 discloses the relationship in Table 2. Currently we regard egg weights of 56-60 grams as being desirable. A practicable range for selection purposes would be 54-64 grams. If we accept the PEI formula, the desired adult body weights would be from 1680 to 1800 grams—or not greater than four pounds. If satisfactory egg weight could be maintained, lowered body weights would result in K values
TABLE 2.—Expected body weights for hens laying eggs weighing from 54 to 64 grams, when K=l. The expected body weight=30Xegg weight Egg weights Grams 54 55 56 57 58 59 60 61 62 63 64
Oz./Doz. 23 23 24 24 25 25 25 26 26 27 " 27
Expected body weight Grams
Pounds
1,620 1,650 1,680 1,710 1,740 1,770 1,800 1,830 1,860 1,890 1,920
3.6 3.6 3.7 3.8 3.8 3.9 4.0 4.0 4.1 4.2 4.2
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
EW (gm.)
Lines
greater than one. This likelihood, however, has been seriously opposed by several important genetic interrelationships, such as the positive correlation between body size and egg size within the range of commercial acceptance. Egg weight in most instances varies directly with body weight. Both egg weight and body weight have relatively high heritability values. At first thought, these factors might seem to be detrimental to selection by means of PEI values. If, however, one considers the PEI value as the criterion for selection, then the K value will have an important influence. In reality, selection for a high K value is selection for a negative correlation between egg weight and body weight. However, the inclusion of an acceptable EW in the numerator of the formula guards against low PEI values for practical consideration. The final consideration would be of the PEI values themselves. When determining feed efficiency for broilers, it is generally accepted that a value of 1.0 (or 100% efficiency) would be optimum. It has been suggested that a lesser value may be possible by flushing feed through broilers, but the commercial production of a gram of meat for each gram of feed consumed is an objective which has not yet been attained.
25
PERFORMANCE EFFICIENCY TABLE 3.—Intermediate and ultimate values derived in the calculation of relative performance efficiencies for 16 flocks of egg-production hens P
EW
BW
Pounds feed/hen days
F
1 16
64.4 66.6
57.2 57.0
1,948 2,052
2,562/10,410 2,670/10,960
111.7 110.7
2 15
65.2 67.0
56.0 56.2
1,934 2,043
2,602/10,204 2,496/9,837
3 14
64.1 64.6
56.0 58.2
1,979 1,925
4 13
65.3 64.8
57.0 56.6
5 9
62.3 63.2
6 10
30 (EW) 2 P
(BW) F
PEI
3,271.8 3,249.0
6,221,176 6,491,502
217,591.6 227,156.4
28.6 28.6
115.8 114.3
3,136.0 3,158.4
6,134,016 6,348,384
233,959.2 233,514.9
27.4 27.2
2,455/10,192 2,672/10,722
109.4 113.1
3,136.0 3,387.2
6,030,528 6,564,394
216,500.0 217,712.5
27.9 30.2
2,048 2,066
2,778/10,594 2,467/10,221
119.0 109.6
3,249.0 3,203.6
6,364,841 6,227,798
243,712.0 226,433.6
26.1 27.5
56.6 57.6
2,043 2,061
2,581/10,552 2,624/10,282
111.0 115.9
3,203.6 3,317.8
5,987,528 6,290,549
226,773.0 238,869.9
26.4 26.3
67.9 63.2
57.0 57.5
2,052 2,111
2,673/10,484 2,547/10,209
115.7 113.2
3,249.0 3,306.3
6,618,213 6,268,745
237,416.4 238,065.2
27.9 26.2
7 12
65.7 62.6
56.1 56.7
1,989 1,934
2,520/10,239 2,552/10,722
111.0 108.1
3,147.2 3,214.9
6,203,131 6,037,582
220,779.0 209,065.4
28.1 28.9
8 11
67.0 63.9
57.4 56.3
1,957 2,011
2,677/10,557 2,338/9,910
115.1 107.1
3,294.8 3,169.7
6,622,548 6,076,315
225,250.4 215,328.1
29.4 28.2
Similarly, a hen that is 100% efficient might be expected to produce one 57 gram egg each day while consuming 57 grams of feed. Substitution of 30EW-H BW for K in the PEI formula results in the following: PEI = PEI =
(30EW + BW)(EW)(P) F
and
3omw)2P BW-F
Employment of the formula for PEI permits determination of how close the hen, or the flock, is to maximum efficiency. In Tables 3, 4 and 5, PEI values for flocks at this station have been calculated. Table 3 includes the progressive mathematical factors leading to the respective PEI determinations. Sixteen flocks provided a range of PEI values from 26.1 to 30.2 in Table 3. This means that flock # 4 performed at a 26.1% rate of efficiency in regard to the potential considered in the first sentence of
(EW) 2
this paragraph. Thus we see that PEI may be useful not only in terms of a selection program for poultry breeders, but also in terms of a flock analysis program. Tables 4 and 5 demonstrate the potential use of this criterion when comparing egg performances TABLE 4.—Performance efficiency for hens on nutrition exp Feed cons.
Body wt.
Treatment
Egg prod.
Egg wt.
Basal 0 . 1 % DLMethionine 0 . 1 % L-Lysine DZ Methionine-}L-xysine
65.8
%
gm. 56.6
64.7 64.2
57.0 57.2
113 114
2,005 2,067
27.9 26.7
64.8
56.8
110
1,973
28.6
gm./day gm. 113 1,994
PEI
28.0
TABLE 5.—Performance efficiency when production varies
Treatment
Egg prod.
PEI
% 'o Basal (11) Protein) Basal+0.10% DL-Methionine 16% Protein
56.3 60.6 65.8
25.2 26.2 28.0
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
Flock
26
W. MORGAN AND C. W. CARLSON
in nutrition trials. Variables other than diet could be similarly evaluated. Finally, it should be pointed out that one might choose to omit K from the formula for PEL An advantage for considering the PEP = (EW) P - f - F formula is that there would be no restriction on maximum body weight. Then, the efficiency value would not heavily penalize hens which weighed more than 1800 grams (4.0 pounds). However, if PEI is to be used in selection programs designed to improve the efficiency of egg production, it is recommended that the K value be included as a part of the formula.
who are efficiency.
concerned
with
management
REFERENCES
SUMMARY A new method for evaluating performance of egg-production stocks has been proposed. This uniform measurement, which lends itself to international use, employs the metric system throughout. Determination of PEI (Production Efficiency Index) values provides a tool which may be used by breeders, by experimenters, or by those
Chicken Blood Volume: The Hematocrit and Comparison of I131 and Evans Blue Methods ANTHONY
W.
KOTULA
Market Quality Research Division, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705 AND NORMAN
V.
HELBACKA
Department of Poultry Science, University of Maryland, College Park, Maryland 20740 (Received for publication May 8, 1967) INTRODUCTION
B
LOOD volumes of mammals have been 1 studied much more extensively than blood volumes of birds, therefore the procedures used for mammalian blood volume Scientific Article No. A1258. Contribution No. 3779 of the Maryland Agricultural Experiment Station (Department of Poultry Science).
determinations can be expected to serve as a basis for improvement in avian blood volume determinations. In poultry research, determination of trapped plasma in the hematocrit, the effect of blood removal during sampling on the hematocrit and absorption curves, and the use of radioactive tracers for blood volume studies have received lit-
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
Agricultural Research Service, 1966. 1966 Report of egg production tests in the United States and Canada. ARS 44-79-7. Card, L. E., and M. C. Nesheim, 1966. Poultry Production. Lea and Febiger, Philadelphia, Pa. 227-229. Council of American Official Poultry Tests, 1958. Production records for the period 1957-58. Report number 20. Ewing, W. R., 1963. Poultry Nutrition. The Ray Ewing Company, publisher, Pasadena, California: 166. Faulkner, J., 1965. Selling eggs by pound urged. The Poultryman, April 30, issue: 8. Frost, D. V., 1965. Logical steps to metric conversion. Poultry Sci. 44: 1227-1236. Kleiber, M., 1965. The unit for measuring food energy. World Rev. An. Prod. 2: 5-11. Morgan, W., and C. W. Carlson, 1965. Selective efficiency. Poultry Sci. 44: 1401. Quisenberry, J. H., 1965. Feed to food conversion ratios; a new method of evaluating production efficiencies. Poultry Sci. 45: 1408. Wofle, D., 1965. Adoption of the metric system. Science, 149: 139.
W. D. TERMOHLEN
dents to serve in every phase of the industry, with both production and marketing extension specialists, and carrying on both applied and fundamental research, and working cooperatively and in a well-coordinated manner with all other colleges and the United States Department of Agriculture; poultry people of the World working together with common understanding and for the good of the industry through the World's Poultry Industries Council— Again the light in the crystal ball fades briefly and then brightens with a closing message—You have just seen the highlights of the modern poultry industry, one of the most outstanding of our agricultural industries producing among the very top nutritional and necessary foods for mankind; namely, eggs and poultry meat, stabilized and beneficially profitable because its leadership has kept its obligation to the public constantly in mind through its program of economy of production, economy of marketing, quality of product, and merchandising to meet the demand pattern of the times. That, my friends, is what comes from being a historiographer.
Proposed Measure of Performance Efficiency in Laying Hens 1 WALTER MORGAN AND C. W. CARLSON South Dakota State University, Brookings, South Dakota 57006 (Received for publication May 8, 1967)
F
OR many years, percent production was regarded as a most useful criterion in appraising the value of laying hens. Although it remains as one of the best 1
Approved for publication by the Director of the South Dakota Experiment Station as paper 770 of the Journal Series.
efficiency indicators, measures of additional factors such as egg weight, egg quality, body weight and feed consumption have been utilized in the sophistication of productive analyses (Kleiber, 1965). With the development of commercial laying stocks which routinely attain the desired 57 gram
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
cent in poultry and egg dishes and uses; from the county shows, the winners compete in state shows, and the state winners at the National Annual Poultry Congress. The National Annual Poultry Congress—this is the big poultry event of the year and is held under the auspices of the American Poultry Industries Council which is an organization bringing together all local, state, regional and national poultry groups on a delegate basis. This event is held each year at the National Poultry Industry Center, an industry-owned, financed and endowed institution where there is located a huge exhibition hall with permanent exhibits showing the history of the industry and with the offices of the American Poultry Industries Council; poultry journals have become even more important and are not only general in nature, but specialized; the Poultry and Egg National Board with greatly extended activities and regional offices serving all areas of the country; a National Poultry and Egg Quality Merchandising Plan operated for the marketing end of the business along basic principles similar to the greatly extended National Poultry Improvement Plan; every Land-Grant College with a Poultry Industry Department training stu-
PERFORMANCE EFFICIENCY
23
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
egg weight, the measure of feed efficiency quality. The following formula considers has, for the past decade, concerned itself hen-size, egg-size, feed consumed and perwith the relationship of feed consumed to cent production in determining a unit value eggs produced (Ewing, 1963; Card and of performance efficiency index (PEI). The Nesheim, 1966). This has been a conve- PEI value may be used for comparative nient partial measure of performance ef- purposes between flocks or between indificiency. It is simple to use feed efficiency viduals. values for the calculation of profit, as they relate to cost of feed and to egg price, but PEI = F with the inverse relationship between high efficiency and numerical values for feed efK == 30EW -e- BW ficiency, an unnecessary barrier to underEW == average egg weight standing exists. BW == body weight of laying hen With all due respect to the usefulness of the determination of feed efficiency upon P == percent production these bases, there have been people, both in F == feed consumed per day. industry (Faulkner, 1965) and in academic circles (Quisenberry, 1965), who have How does the proposed formula differ strongly advocated that egg size should from presently used calculations for feed efhave been included in the calculations. In ficiency in laying flocks? A basic difference truth, feed efficiency values for flocks is that metric measure is used throughout. which produce undersized eggs are invalid, Use of the metric system has been mandaand the values for flocks which produce ov- tory within the Poultry Science Association ersized eggs do not recognize the economic since 1964, and has been recommended by advantage of the larger eggs. For many most scientific organizations (Frost, 1965; years the standard egg laying contests used and Wolfle, 1965). Present-day determinaa point-system which weighted egg-size as a tions of feed efficiency are basically of two productive factor (Council of American kinds. The first is in terms of kilograms (or Poultry Tests, 1958). A standard compari- pounds) of feed required to produce a son which has been successfully employed dozen eggs. In the aforementioned consideris one that defines feed efficiency as the ation, that would be comparable to 12F-4pounds of feed required to produce a dozen P if we disregard egg weight and body "24 ounce" eggs. Random Sample Tests weight. The second is in terms of kilograms currently report feed efficiency in terms of of feed per kilogram of eggs (or pounds of pounds of feed required to produce a pound feed per pound of eggs), which is of eggs (Agricultural Research Service, F-=- (EW) P. It then becomes obvious that 1966). The incorporation of body weight in the key difference in the newly proposed consideration of this efficiency measure has formula for PEI is "K". How does K imonly briefly been considered (Morgan and prove our determination of performance efCarlson, 1965). ficiency and what is a desirable K value? A useful value for those who are interStudies at this station have indicated that ested in selective efficiency for laying flocks eggs from year-old hens are equal to apmust consider rate of lay (percent produc- proximately one-thirtieth of their body tion), egg size and feed consumed. Other weight. That is, in 30 days a hen which lays considerations which might be considered daily will have laid the equivalent of her pertinent by some are body weight and egg body weight. Data pertinent to the K value
24
W. MORGAN AND C. W. CARLSON
TABLE 1.—Interrelationships of egg weight, body weight and K values for eleven inbred lines of White Leghorns BW (gm.)
K
2 5 3 1 4 10 8 6 12 9 11
53 53 57 52 57 55 55 54 52 57 54
1,785 1,790 1,800 1,600 1,720 1,645 1,630 1,580 1,470 1,606 1,470
0.89 0.89 0.95 0.98 0.99 1.00 1.01 1.02 1.06 1.07 1.10
Avge.
54
1,625
1.00
determination are presented in Table 1. Values range from 0.89 to 1.10, with a population mean value of 1.00, for the lines that are represented. The unweighted averages of 54 gm. and 1625 gm. are smaller than occur in most non-inbred populations. The population value for K is actually 0.9996 or approximately one. When collecting data at this station, we normally use a gram scale to weigh a group of three eggs from each hen. Multiplying this weight by 10 merely necessitates adding a zero. Hence, the relationship between the weight of 30 of her eggs and her body weight in grams can be immediately evaluated by inspection. If 30 eggs weigh more than the hen, the K value will be above one. This is desirable. Contrariwise, if the hen weighs more than the calculated weight of 30 eggs, the K value is below one. An examination of the import of K = 1 discloses the relationship in Table 2. Currently we regard egg weights of 56-60 grams as being desirable. A practicable range for selection purposes would be 54-64 grams. If we accept the PEI formula, the desired adult body weights would be from 1680 to 1800 grams—or not greater than four pounds. If satisfactory egg weight could be maintained, lowered body weights would result in K values
TABLE 2.—Expected body weights for hens laying eggs weighing from 54 to 64 grams, when K=l. The expected body weight=30Xegg weight Egg weights Grams 54 55 56 57 58 59 60 61 62 63 64
Oz./Doz. 23 23 24 24 25 25 25 26 26 27 " 27
Expected body weight Grams
Pounds
1,620 1,650 1,680 1,710 1,740 1,770 1,800 1,830 1,860 1,890 1,920
3.6 3.6 3.7 3.8 3.8 3.9 4.0 4.0 4.1 4.2 4.2
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
EW (gm.)
Lines
greater than one. This likelihood, however, has been seriously opposed by several important genetic interrelationships, such as the positive correlation between body size and egg size within the range of commercial acceptance. Egg weight in most instances varies directly with body weight. Both egg weight and body weight have relatively high heritability values. At first thought, these factors might seem to be detrimental to selection by means of PEI values. If, however, one considers the PEI value as the criterion for selection, then the K value will have an important influence. In reality, selection for a high K value is selection for a negative correlation between egg weight and body weight. However, the inclusion of an acceptable EW in the numerator of the formula guards against low PEI values for practical consideration. The final consideration would be of the PEI values themselves. When determining feed efficiency for broilers, it is generally accepted that a value of 1.0 (or 100% efficiency) would be optimum. It has been suggested that a lesser value may be possible by flushing feed through broilers, but the commercial production of a gram of meat for each gram of feed consumed is an objective which has not yet been attained.
25
PERFORMANCE EFFICIENCY TABLE 3.—Intermediate and ultimate values derived in the calculation of relative performance efficiencies for 16 flocks of egg-production hens P
EW
BW
Pounds feed/hen days
F
1 16
64.4 66.6
57.2 57.0
1,948 2,052
2,562/10,410 2,670/10,960
111.7 110.7
2 15
65.2 67.0
56.0 56.2
1,934 2,043
2,602/10,204 2,496/9,837
3 14
64.1 64.6
56.0 58.2
1,979 1,925
4 13
65.3 64.8
57.0 56.6
5 9
62.3 63.2
6 10
30 (EW) 2 P
(BW) F
PEI
3,271.8 3,249.0
6,221,176 6,491,502
217,591.6 227,156.4
28.6 28.6
115.8 114.3
3,136.0 3,158.4
6,134,016 6,348,384
233,959.2 233,514.9
27.4 27.2
2,455/10,192 2,672/10,722
109.4 113.1
3,136.0 3,387.2
6,030,528 6,564,394
216,500.0 217,712.5
27.9 30.2
2,048 2,066
2,778/10,594 2,467/10,221
119.0 109.6
3,249.0 3,203.6
6,364,841 6,227,798
243,712.0 226,433.6
26.1 27.5
56.6 57.6
2,043 2,061
2,581/10,552 2,624/10,282
111.0 115.9
3,203.6 3,317.8
5,987,528 6,290,549
226,773.0 238,869.9
26.4 26.3
67.9 63.2
57.0 57.5
2,052 2,111
2,673/10,484 2,547/10,209
115.7 113.2
3,249.0 3,306.3
6,618,213 6,268,745
237,416.4 238,065.2
27.9 26.2
7 12
65.7 62.6
56.1 56.7
1,989 1,934
2,520/10,239 2,552/10,722
111.0 108.1
3,147.2 3,214.9
6,203,131 6,037,582
220,779.0 209,065.4
28.1 28.9
8 11
67.0 63.9
57.4 56.3
1,957 2,011
2,677/10,557 2,338/9,910
115.1 107.1
3,294.8 3,169.7
6,622,548 6,076,315
225,250.4 215,328.1
29.4 28.2
Similarly, a hen that is 100% efficient might be expected to produce one 57 gram egg each day while consuming 57 grams of feed. Substitution of 30EW-H BW for K in the PEI formula results in the following: PEI = PEI =
(30EW + BW)(EW)(P) F
and
3omw)2P BW-F
Employment of the formula for PEI permits determination of how close the hen, or the flock, is to maximum efficiency. In Tables 3, 4 and 5, PEI values for flocks at this station have been calculated. Table 3 includes the progressive mathematical factors leading to the respective PEI determinations. Sixteen flocks provided a range of PEI values from 26.1 to 30.2 in Table 3. This means that flock # 4 performed at a 26.1% rate of efficiency in regard to the potential considered in the first sentence of
(EW) 2
this paragraph. Thus we see that PEI may be useful not only in terms of a selection program for poultry breeders, but also in terms of a flock analysis program. Tables 4 and 5 demonstrate the potential use of this criterion when comparing egg performances TABLE 4.—Performance efficiency for hens on nutrition exp Feed cons.
Body wt.
Treatment
Egg prod.
Egg wt.
Basal 0 . 1 % DLMethionine 0 . 1 % L-Lysine DZ Methionine-}L-xysine
65.8
%
gm. 56.6
64.7 64.2
57.0 57.2
113 114
2,005 2,067
27.9 26.7
64.8
56.8
110
1,973
28.6
gm./day gm. 113 1,994
PEI
28.0
TABLE 5.—Performance efficiency when production varies
Treatment
Egg prod.
PEI
% 'o Basal (11) Protein) Basal+0.10% DL-Methionine 16% Protein
56.3 60.6 65.8
25.2 26.2 28.0
Downloaded from http://ps.oxfordjournals.org/ at Brunel University on April 15, 2015
Flock
26
W. MORGAN AND C. W. CARLSON
in nutrition trials. Variables other than diet could be similarly evaluated. Finally, it should be pointed out that one might choose to omit K from the formula for PEL An advantage for considering the PEP = (EW) P - f - F formula is that there would be no restriction on maximum body weight. Then, the efficiency value would not heavily penalize hens which weighed more than 1800 grams (4.0 pounds). However, if PEI is to be used in selection programs designed to improve the efficiency of egg production, it is recommended that the K value be included as a part of the formula.
who are efficiency.
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REFERENCES
SUMMARY A new method for evaluating performance of egg-production stocks has been proposed. This uniform measurement, which lends itself to international use, employs the metric system throughout. Determination of PEI (Production Efficiency Index) values provides a tool which may be used by breeders, by experimenters, or by those
Chicken Blood Volume: The Hematocrit and Comparison of I131 and Evans Blue Methods ANTHONY
W.
KOTULA
Market Quality Research Division, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705 AND NORMAN
V.
HELBACKA
Department of Poultry Science, University of Maryland, College Park, Maryland 20740 (Received for publication May 8, 1967) INTRODUCTION
B
LOOD volumes of mammals have been 1 studied much more extensively than blood volumes of birds, therefore the procedures used for mammalian blood volume Scientific Article No. A1258. Contribution No. 3779 of the Maryland Agricultural Experiment Station (Department of Poultry Science).
determinations can be expected to serve as a basis for improvement in avian blood volume determinations. In poultry research, determination of trapped plasma in the hematocrit, the effect of blood removal during sampling on the hematocrit and absorption curves, and the use of radioactive tracers for blood volume studies have received lit-
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Agricultural Research Service, 1966. 1966 Report of egg production tests in the United States and Canada. ARS 44-79-7. Card, L. E., and M. C. Nesheim, 1966. Poultry Production. Lea and Febiger, Philadelphia, Pa. 227-229. Council of American Official Poultry Tests, 1958. Production records for the period 1957-58. Report number 20. Ewing, W. R., 1963. Poultry Nutrition. The Ray Ewing Company, publisher, Pasadena, California: 166. Faulkner, J., 1965. Selling eggs by pound urged. The Poultryman, April 30, issue: 8. Frost, D. V., 1965. Logical steps to metric conversion. Poultry Sci. 44: 1227-1236. Kleiber, M., 1965. The unit for measuring food energy. World Rev. An. Prod. 2: 5-11. Morgan, W., and C. W. Carlson, 1965. Selective efficiency. Poultry Sci. 44: 1401. Quisenberry, J. H., 1965. Feed to food conversion ratios; a new method of evaluating production efficiencies. Poultry Sci. 45: 1408. Wofle, D., 1965. Adoption of the metric system. Science, 149: 139.