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Individuality as Affecting Points of Egg Quality*
INDIVIDUALITY AS AFFECTING POINTS OF EGG QUALITY* C. S. P L A T T
* Read a t t h e a n n u a l meeting of P o u l t r y Science Association, held a t Lafayette, I n d i a n a , August 21-24, 1928. i BENJAMIN, E A B L W. A S t u d y of Selections for t h e Size, Shape a n d Color of Hen's Eggs." Cornell University, A g r i c u l t u r a l E x p e r i m e n t Station, Memoir 31. May 1920. 2 PABKEK,
GOSSMAN
AND LIPPINCOTT.
P O U L T R Y SCIENCE, Vol. 5, No. 3 p a g e 131.
189
"Studies
on
Egg
Quality."
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
The effect of the individuality of the bird upon such egg quality points as weight of egg, shape of egg, and color of egg shell has been reported upon several occasions, one of the most noteworthy being the study made by Dr. Benjamin 1 at Cornell. All of the studies bear out his conclusion that these factors are very largely influenced by the natural tendency of the fowl. Parker, Gossman and Lippincott 2 reported that the color of egg yolk varied with individual birds but when these birds were fed specific amounts of green food this variation disappeared to a large extent. One bird in the group consistently produced a light yolk, however, even though she did consume relatively large amounts of green food. The study reported herein was made primarily for the purpose of determining the effect of individuality upon the texture of the shell and the firmness of the white, although egg weight was also noted. This study was restricted to birds under commercial conditions and the eggs were graded according to commercial grades. Twenty "White Leghorn Pullets were used and these were selected when six months of age. Normal healthy birds were chosen but no attempt was made to select any particular type. Only seventeen are reported as the other three died during the year. The birds were placed in the laying house when selected and were kept confined during the entire year. The scratch grain consisted of equal parts of cracked corn and wheat. The dry mash consisted of equal parts of corn meal, wheat bran, pinhead oats, red-dog flour and meat scraps (50 per cent protein). This was always available in hoppers. A moist mash was fed daily consisting of equal parts of corn meal, rolled oats and semisolid buttermilk. Cod-liver oil was fed daily in the moist mash
POULTRY
190
SCIENCE
T A B L E 1—SHOWING P E R C E N T A G E S OP V A R I O U S G R A D E S O F E G G S P R O D U C E D B Y I N D I V I D U A L W H I T E LEGHORN P U L L E T S Bird No.
No. of Eggs
2052 2055 2056 2060 2063 2064 2065 2069 2072 2074 2075 2080 2083 2085 2087 2092 2094
110 170 115 142 155 120 121 63 180 146 122 63 145 132 120 168 127
Egg Weight Extras Mediums Pullets
98 87 21 33 76 30 95 29 24 94 18 70 18 21 73 83 74
2 13 78 34 22 63 5 42 58 6 50 30 54 63 27 17 25
0 0 1 33 2 7 0 29 18 0 32 0 28 16 0 0 1
Shell Texture Good Poor
80 53 37 37 87 48 88 46 91 80 85 32 90 27 84 96 71
20 47 63 63 13 52 12 54 9 20 15 68 10 73 16 4 29
White Firm W :ater;
35 75 85 50 55 70 20 28 75 57 55 75 80 40 65 70 35
65 25 15 50 45 30 80 72 25 43 45 25 20 60 35 30 65
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
and at the rate of one per cent of the entire ration. Green food was fed daily at the rate of four pounds per hundred birds. Sprouted oats were used during the winter and green alfalfa during the summer. Oyster shell and limestone grit (85 per cent calcium carbonate) were constantly available in hoppers. No artificial lights were used. Each egg was marked with the date laid and the number of the bird producing it. All eggs were kept in baskets for an average period of eight days before being examined. They were held at cellar temperature, about 60° At the time of the examination the eggs were packed in an egg case with the small ends down. The case was then shuffled back and forth across the floor, moving it an arm's length each time. One hundred movements were used in each instance. This had been previously found necessary for the proper determination of the "watery white" eggs. After this handling the eggs were removed and weighed. They were graded as " e x t r a s , " which included all eggs weighing 23 ounces or more per dozen; "mediums," which included all eggs weighing 21 and 22 ounces per dozen; and " p u l l e t s " which included all eggs under 21
QUALITY
IN
EGGS
191
T A B L E 2 — S H O W I N G V A R I A B I L I T Y I N P E R C E N T A G E S OP V A R I O U S GRADES OP E G G S PRODUCED B Y W H I T E LEGHORN P U L L E T S
Mean of percentage S. D. of percentages C. V. of percentages
"Extras"
Good Texture
Firm Whites
56 31 54.6
67 23 34.3
57 19 33.3
Table 1 clearly illustrates how the individual affects the market grade of egg produced, varying from bird number 2075 which produced 18 per cent of " e x t r a s " to bird number 2065 which produced 95 per cent of " e x t r a s . " We see the same situation in the matter of shell texture, varying from a production of 27 per cent of good textured eggs from bird number 2085 to 96 percent of such eggs from bird number 2092. The condition of the white also exhibits the same tendency and we find bird number 2083 producing a high quality product in this respect with 80 per cent of her eggs maintaining a firm white while on the other hand bird number 2065 produced eggs that contained only 20 per cent of firm whites. The extent of the variation in shell texture and condition of white among the individuals is not so large as the variation in egg weight. (See Table 2) This would indicate that the effect of the individual is not so marked in these particulars and it may be that this variation will be reduced still further when the birds are placed on an all-mash ration containing all the mineral requirements. Such a ration would insure each bird receiving identical nutrients
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
ounces per dozen. After weighing, the eggs were candled for shell texture and firmness of white. Two grades of shell texture were established as shown in the accompanying illustrations. Five grades were used at the start but it was found impossible to distinguish between them with any degree of accuracy so the eggs were called either " g o o d " or " p o o r " according to how closely they approached the standard illustrated. The presence of a watery white was determined by the movement of the edge of the air-cell. If the lower side of the aircell remained stationary when the egg was revolved before the candle the white was graded as "firm" but if the edge exhibited a rippling effect the white was graded as " w a t e r y . "
192
POULTRY
SCIENCE
whereas in the ration used in this experiment it would have been possble for the birds to exhibit some preference in the chose of mash, grain, shell or grit. Under existing commercial conditions, however, there is no doubt but that the individual bird has a marked effect on the market quality of strictly fresh eggs. SUMMARY Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
Seventeen "White Leghorn pullets were fed a ration similar to that used on commercial poultry farms. All of the eggs produced were marked with the number of the bird and date laid. Approximately one week after being produced these eggs were examined for weight, shell texture and firmness of white. The individual bird had a marked effect upon all three points observed, the weight of the egg being influenced to a greater extent by the individuality of the bird than the other two factors.
* Read a t t h e a n n u a l meeting of P o u l t r y Science Association, held a t Lafayette, I n d i a n a , August 21-24, 1928. i BENJAMIN, E A B L W. A S t u d y of Selections for t h e Size, Shape a n d Color of Hen's Eggs." Cornell University, A g r i c u l t u r a l E x p e r i m e n t Station, Memoir 31. May 1920. 2 PABKEK,
GOSSMAN
AND LIPPINCOTT.
P O U L T R Y SCIENCE, Vol. 5, No. 3 p a g e 131.
189
"Studies
on
Egg
Quality."
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
The effect of the individuality of the bird upon such egg quality points as weight of egg, shape of egg, and color of egg shell has been reported upon several occasions, one of the most noteworthy being the study made by Dr. Benjamin 1 at Cornell. All of the studies bear out his conclusion that these factors are very largely influenced by the natural tendency of the fowl. Parker, Gossman and Lippincott 2 reported that the color of egg yolk varied with individual birds but when these birds were fed specific amounts of green food this variation disappeared to a large extent. One bird in the group consistently produced a light yolk, however, even though she did consume relatively large amounts of green food. The study reported herein was made primarily for the purpose of determining the effect of individuality upon the texture of the shell and the firmness of the white, although egg weight was also noted. This study was restricted to birds under commercial conditions and the eggs were graded according to commercial grades. Twenty "White Leghorn Pullets were used and these were selected when six months of age. Normal healthy birds were chosen but no attempt was made to select any particular type. Only seventeen are reported as the other three died during the year. The birds were placed in the laying house when selected and were kept confined during the entire year. The scratch grain consisted of equal parts of cracked corn and wheat. The dry mash consisted of equal parts of corn meal, wheat bran, pinhead oats, red-dog flour and meat scraps (50 per cent protein). This was always available in hoppers. A moist mash was fed daily consisting of equal parts of corn meal, rolled oats and semisolid buttermilk. Cod-liver oil was fed daily in the moist mash
POULTRY
190
SCIENCE
T A B L E 1—SHOWING P E R C E N T A G E S OP V A R I O U S G R A D E S O F E G G S P R O D U C E D B Y I N D I V I D U A L W H I T E LEGHORN P U L L E T S Bird No.
No. of Eggs
2052 2055 2056 2060 2063 2064 2065 2069 2072 2074 2075 2080 2083 2085 2087 2092 2094
110 170 115 142 155 120 121 63 180 146 122 63 145 132 120 168 127
Egg Weight Extras Mediums Pullets
98 87 21 33 76 30 95 29 24 94 18 70 18 21 73 83 74
2 13 78 34 22 63 5 42 58 6 50 30 54 63 27 17 25
0 0 1 33 2 7 0 29 18 0 32 0 28 16 0 0 1
Shell Texture Good Poor
80 53 37 37 87 48 88 46 91 80 85 32 90 27 84 96 71
20 47 63 63 13 52 12 54 9 20 15 68 10 73 16 4 29
White Firm W :ater;
35 75 85 50 55 70 20 28 75 57 55 75 80 40 65 70 35
65 25 15 50 45 30 80 72 25 43 45 25 20 60 35 30 65
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
and at the rate of one per cent of the entire ration. Green food was fed daily at the rate of four pounds per hundred birds. Sprouted oats were used during the winter and green alfalfa during the summer. Oyster shell and limestone grit (85 per cent calcium carbonate) were constantly available in hoppers. No artificial lights were used. Each egg was marked with the date laid and the number of the bird producing it. All eggs were kept in baskets for an average period of eight days before being examined. They were held at cellar temperature, about 60° At the time of the examination the eggs were packed in an egg case with the small ends down. The case was then shuffled back and forth across the floor, moving it an arm's length each time. One hundred movements were used in each instance. This had been previously found necessary for the proper determination of the "watery white" eggs. After this handling the eggs were removed and weighed. They were graded as " e x t r a s , " which included all eggs weighing 23 ounces or more per dozen; "mediums," which included all eggs weighing 21 and 22 ounces per dozen; and " p u l l e t s " which included all eggs under 21
QUALITY
IN
EGGS
191
T A B L E 2 — S H O W I N G V A R I A B I L I T Y I N P E R C E N T A G E S OP V A R I O U S GRADES OP E G G S PRODUCED B Y W H I T E LEGHORN P U L L E T S
Mean of percentage S. D. of percentages C. V. of percentages
"Extras"
Good Texture
Firm Whites
56 31 54.6
67 23 34.3
57 19 33.3
Table 1 clearly illustrates how the individual affects the market grade of egg produced, varying from bird number 2075 which produced 18 per cent of " e x t r a s " to bird number 2065 which produced 95 per cent of " e x t r a s . " We see the same situation in the matter of shell texture, varying from a production of 27 per cent of good textured eggs from bird number 2085 to 96 percent of such eggs from bird number 2092. The condition of the white also exhibits the same tendency and we find bird number 2083 producing a high quality product in this respect with 80 per cent of her eggs maintaining a firm white while on the other hand bird number 2065 produced eggs that contained only 20 per cent of firm whites. The extent of the variation in shell texture and condition of white among the individuals is not so large as the variation in egg weight. (See Table 2) This would indicate that the effect of the individual is not so marked in these particulars and it may be that this variation will be reduced still further when the birds are placed on an all-mash ration containing all the mineral requirements. Such a ration would insure each bird receiving identical nutrients
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
ounces per dozen. After weighing, the eggs were candled for shell texture and firmness of white. Two grades of shell texture were established as shown in the accompanying illustrations. Five grades were used at the start but it was found impossible to distinguish between them with any degree of accuracy so the eggs were called either " g o o d " or " p o o r " according to how closely they approached the standard illustrated. The presence of a watery white was determined by the movement of the edge of the air-cell. If the lower side of the aircell remained stationary when the egg was revolved before the candle the white was graded as "firm" but if the edge exhibited a rippling effect the white was graded as " w a t e r y . "
192
POULTRY
SCIENCE
whereas in the ration used in this experiment it would have been possble for the birds to exhibit some preference in the chose of mash, grain, shell or grit. Under existing commercial conditions, however, there is no doubt but that the individual bird has a marked effect on the market quality of strictly fresh eggs. SUMMARY Downloaded from http://ps.oxfordjournals.org/ at New York University on May 30, 2015
Seventeen "White Leghorn pullets were fed a ration similar to that used on commercial poultry farms. All of the eggs produced were marked with the number of the bird and date laid. Approximately one week after being produced these eggs were examined for weight, shell texture and firmness of white. The individual bird had a marked effect upon all three points observed, the weight of the egg being influenced to a greater extent by the individuality of the bird than the other two factors.