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 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN 
 
 L161 O-1096 
 
An Analysis of 
 
 Milking Shorthorn 
 
 Milk Records 
 
 By W. L. GAINES 
 
 Bulletin 498 
 
 UNIVERSITY OF ILLINOIS 
 AGRICULTURAL EXPERIMENT STATION 
 
CONTENTS 
 
 PAGE 
 
 FAT PERCENTAGE AND YIELDS OF MILK, FAT, AND FCM 554 
 
 AGE AT CALVING AND MILK YIELD 561 
 
 Revision of Age-Correction Factors for Milking Shorthorns 561 
 
 Other Data on the Relation of Age to Yield 565 
 
 Milk Yield Influenced More by Weight Than by Age 570 
 
 MONTH OF CALVING AND MILK-ENERGY YIELD 571 
 
 FREQUENCY OF MILKING AND MILK-ENERGY YIELD 573 
 
 SUMMARY 574 
 
 TABLE OF AGE-CORRECTION FACTORS FOR 
 
 MILKING SHORTHORNS... .576 
 
 Urbana, Illinois August, 1943 
 
 Publication* in the Bulletin series report the results of investigations made 
 or sponsored by the Experiment Station 
 
An Analysis of Milking Shorthorn 
 Milk Records 
 
 By W. L. GAINES, Chief in Milk Production 
 
 J^XTENSIVE STATISTICAL STUDIES have been made of 
 
 1 , the milk- and fat-production records of the various breeds of 
 dairy cattle. No such studies have been carried out, however, 
 
 for Milking Shorthorns, a breed bred for both milk and meat produc- 
 tion. Official records similar to those kept for strictly dairy breeds are 
 available for this dual-purpose breed, having been published contin- 
 uously since 1915, except in 1918, in the Milking Shorthorn Year Book. 
 It was therefore the purpose of the study reported here to subject these 
 records to a statistical analysis. 
 
 For this study records from Volumes 9 to 23 (1924-1938), which 
 include R.M. (Record of Merit) numbers 1,910 to 8,564, were used 
 (Fig. 1). Only records which included age of cow at calving, length 
 of record, milk-fat yield, and fat percentage in addition to milk yield 
 were studied. 
 
 To appear in the Year Book a record must meet certain require- 
 ments. "Double letter" (DL) records require that a cow give birth to 
 a living calf within 14 months after freshening; "single letter" (SL) 
 records have no calving requirement. An SL cow 30 months old or 
 younger when her record was started must produce at least 5,250 
 pounds of milk or 210 pounds of fat before her record is accepted (it 
 is not necessary to satisfy both requirements but only one). An SL 
 cow whose record starts when she is 60 months old or older must pro- 
 duce at least 8,000 pounds of milk or 300 pounds of fat. Requirements 
 for cows in between these ages are graduated uniformly on a day basis. 
 The requirement for DL records is .9 that of SL records, plus the 
 calving requirement already mentioned. 
 
 A record is not necessarily confined to a single lactation and may 
 start at any time, but in actual practice most of the records start within 
 a week after calving. If a second lactation is involved, the length of 
 record includes any dry period intervening. Some records were shorter 
 than the maximum (SL-<12 mo.; DL-<10 mo.), either because the 
 cow went dry or because the record-keeping was discontinued. 
 
 551 
 
552 
 
 BULLETIN No. 498 
 
 [August, 
 
 
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 MILKING SHORTHORN MILK RECORDS 
 
 553 
 
 For the purposes of this study the records were grouped as follows: 
 
 Milkings 
 per day 
 
 2 
 
 2 
 
 2 
 
 2 
 
 3 
 
 3 
 
 Designation Number of 
 
 Letter Length of record of group records 
 
 Single 12 months (365 days) 2x-SL-12mo. 2,585 
 
 Single Less than 12 months 2x-SL-<12mo. 2,130 
 
 Double 10 months (305 days) 2x-DL-10mo. 504 
 
 Double Less than 10 months 2x-DL-<10mo. 462 
 
 Single 12 months (365 days) 3x-SL-12mo. 345 
 
 Single Less than 12 months 3x-SL-<12mo. 285 
 
 Total records 6,31 1 
 
 There were 48 DL records in the 3x category but because they 
 occurred so infrequently, they are not included in this study. There 
 were 8 records for cows milked four times a day and 6 of these rec- 
 ords in a 4x-SL-12 mo. group are considered because they afford 
 some indication of the response of the breed to such extra-pressure 
 methods of management. 
 
 TABLE 1. FREQUENCY DISTRIBUTION OF RECORDS ACCORDING TO FAT PERCENTAGE 
 (Figures indicate percent of total records in each group) 
 
 
 Group 
 
 class* All 
 records 
 
 2X-SL- 
 12 mo. 
 
 2x-SL- 
 <12 mo. 
 
 2x-DL- 
 10 mo. 
 
 2x-DL- 
 < 10 mo. 
 
 3x-SL- 
 12 mo. 
 
 3x-SL- 
 <12 mo. 
 
 2.9 
 3.0 
 
 
 06 
 11 
 
 .04 
 .08 
 
 
 09 
 14 
 
 
 20 
 
 
 
 29 
 
 '.'35 
 
 3.1 
 
 
 41 
 
 .43 
 
 
 47 
 
 
 
 .43 
 
 
 58 
 
 .35 
 
 3.2 
 
 1 
 
 01 
 
 .97 
 
 1 
 
 13 
 
 1 
 
 19 
 
 .65 
 
 1 
 
 16 
 
 .70 
 
 3.3 
 
 1 
 
 79 
 
 1.62 
 
 1 
 
 92 
 
 1 
 
 79 
 
 1.30 
 
 2.61 
 
 2.11 
 
 3.4... 
 
 . 3 
 
 45 
 
 2.44 
 
 3 
 
 80 
 
 5 
 
 36 
 
 4.55 
 
 4 
 
 64 
 
 3.51 
 
 3.5 
 
 5 
 
 13 
 
 4.99 
 
 5 
 
 45 
 
 5 
 
 56 
 
 3.68 
 
 6 
 
 38 
 
 4.21 
 
 3.6 
 
 7 
 
 43 
 
 7.35 
 
 7 
 
 09 
 
 7 
 
 14 
 
 6.49 
 
 12 
 
 75 
 
 6.32 
 
 3.7 
 
 10 
 
 09 
 
 9.79 
 
 10 
 
 23 
 
 9 
 
 72 
 
 8.01 
 
 11 
 
 88 
 
 13.68 
 
 3.8 
 
 12 
 
 12 
 
 12.46 
 
 11 
 
 88 
 
 9 
 
 72 
 
 11.04 
 
 13 
 
 04 
 
 15.79 
 
 3.9... 
 
 . 12 
 
 06 
 
 12.34 
 
 11 
 
 83 
 
 14 
 
 29 
 
 8.44 
 
 12 
 
 46 
 
 12.63 
 
 4.0 
 
 11 
 
 96 
 
 11.99 
 
 12 
 
 86 
 
 8 
 
 93 
 
 10.17 
 
 11 
 
 59 
 
 13.68 
 
 4.1 
 
 10 
 
 19 
 
 10.95 
 
 9 
 
 15 
 
 10 
 
 91 
 
 11.90 
 
 7 
 
 54 
 
 10.18 
 
 4.2 
 
 8 
 
 08 
 
 8.01 
 
 7 
 
 89 
 
 8 
 
 73 
 
 10.39 
 
 6 
 
 96 
 
 6.67 
 
 4.3 
 
 5 
 
 91 
 
 6.54 
 
 5 
 
 73 
 
 5 
 
 95 
 
 5.84 
 
 2 
 
 61 
 
 5.61 
 
 4.4... 
 
 . 4 
 
 47 
 
 4.29 
 
 4 
 
 69 
 
 5 
 
 56 
 
 6.06 
 
 3 
 
 19 
 
 1.40 
 
 4.5 
 
 2 
 
 19 
 
 2.05 
 
 2 
 
 .39 
 
 1 
 
 79 
 
 3.90 
 
 1 
 
 16 
 
 1.05 
 
 4.6 
 
 1 
 
 35 
 
 1.43 
 
 1 
 
 03 
 
 1 
 
 79 
 
 2.81 
 
 
 29 
 
 1.05 
 
 4.7 
 
 
 95 
 
 1.08 
 
 
 85 
 
 
 79 
 
 1.95 
 
 
 
 .35 
 
 4.8 
 
 
 49 
 
 .43 
 
 
 .56 
 
 
 60 
 
 .87 
 
 
 29 
 
 
 4.9 
 
 
 35 
 
 .35 
 
 
 .42 
 
 
 
 
 
 29 
 
 .35 
 
 5.0 
 
 
 13 
 
 .04 
 
 
 23 
 
 
 
 .43 
 
 
 
 
 5.1 
 
 
 08 
 
 .12 
 
 
 
 
 
 .43 
 
 
 29 
 
 
 5.2 
 
 
 10 
 
 .12 
 
 
 09 
 
 
 
 .22 
 
 
 
 
 5.3 
 
 
 05 
 
 .04 
 
 
 05 
 
 
 
 .22 
 
 
 
 
 5.4... 
 
 
 02 
 
 .04 
 
 
 
 
 
 
 
 
 
 5.5 
 
 
 02 
 
 .04 
 
 
 
 
 
 
 
 
 
 5.6 
 
 
 02 
 
 
 
 
 
 
 .22 
 
 
 
 
 Lower class limit. The published records report fat percentage to the closest second decimal; 
 hence the 2.9 class includes actual values from 2.895 up to but not including 2.995. 
 
554 BULLETIN No. 498 [August, 
 
 FAT PERCENTAGE AND YIELDS OF MILK, 
 FAT, AND FCM 
 
 The percentage frequency distribution with regard to fat percent- 
 age for each of the six groups and all the groups together is given in 
 Table 1. Similar data with respect to milk yield are given in Table 2. 
 
 Fat percentage and milk yield. For fat percentage the groups 
 did not differ greatly in means, standard deviations, and coefficients of 
 variation (CV), but for milk yield there were decided differences in 
 means and standard deviations, altho differences in CV were not large 
 
 TABLE 2. FREQUENCY DISTRIBUTION OF RECORDS ACCORDING TO MILK YIELD 
 (Figures indicate percent of total records in each group) 
 
 
 
 
 
 Group 
 
 
 
 
 Milk yield 
 
 
 
 
 
 
 
 
 class* 
 
 All 
 
 2x-SL- 
 
 2x-SL- 
 
 2x-DL- 
 
 2x-DL- 
 
 3x-SL- 
 
 3x-SL- 
 
 
 records 
 
 12 mo. 
 
 <12 mo. 
 
 10 mo. 
 
 <10 mo. 
 
 12 mo. 
 
 <12 mo. 
 
 Ib. 
 
 
 
 
 
 
 
 
 3 500 
 
 .02 
 
 .04 
 
 
 
 
 
 
 4 000 
 
 13 
 
 .12 
 
 .05 
 
 .60 
 
 .22 
 
 
 
 4 500 
 
 1.03 
 
 .66 
 
 .70 
 
 2.39 
 
 4.55 
 
 
 
 5 000 
 
 4.20 
 
 3.91 
 
 3.52 
 
 9.94 
 
 8.01 
 
 
 .70 
 
 5 500 
 
 6.70 
 
 6.50 
 
 7.37 
 
 9.74 
 
 9.52 
 
 .58 
 
 1.05 
 
 6 000... 
 
 . 8.34 
 
 8.51 
 
 9.58 
 
 9.15 
 
 9.96 
 
 1.16 
 
 2.11 
 
 6 500 
 
 8.89 
 
 9.90 
 
 8.87 
 
 10.93 
 
 9.31 
 
 2.03 
 
 3.86 
 
 7 000 
 
 9.87 
 
 9.44 
 
 10.19 
 
 12.33 
 
 16.23 
 
 2.61 
 
 5.61 
 
 7 500 
 
 9.00 
 
 8.63 
 
 9.86 
 
 10.14 
 
 10.39 
 
 3.19 
 
 8.77 
 
 8 000 
 
 11.74 
 
 11.76 
 
 14.37 
 
 8.35 
 
 9.74 
 
 4.35 
 
 10.18 
 
 8 500... 
 
 ... 8.29 
 
 7.89 
 
 9.81 
 
 7.95 
 
 6.71 
 
 4.06 
 
 8.77 
 
 9 000 
 
 .... 7.13 
 
 7.35 
 
 7.32 
 
 7.36 
 
 4.55 
 
 5.80 
 
 9.12 
 
 9 500 
 
 .... 5.21 
 
 5.69 
 
 4.93 
 
 3.18 
 
 4.11 
 
 4.93 
 
 8.77 
 
 10 000 
 
 4.66 
 
 4.68 
 
 4.93 
 
 1.79 
 
 2.81 
 
 5.51 
 
 9.47 
 
 10 500 
 
 .... 3.52 
 
 4.06 
 
 2.58 
 
 1.39 
 
 .65 
 
 9.28 
 
 7.02 
 
 11 000... 
 
 2.81 
 
 3.02 
 
 1.97 
 
 2.39 
 
 1.08 
 
 7.25 
 
 5.26 
 
 11 500 
 
 2.09 
 
 2.36 
 
 1.36 
 
 .80 
 
 .43 
 
 7.25 
 
 3.86 
 
 12 000 
 
 1.66 
 
 1.35 
 
 .75 
 
 .99 
 
 .65 
 
 8.99 
 
 5.26 
 
 12 500 
 
 1.39 
 
 1.16 
 
 .70 
 
 .20 
 
 .43 
 
 8.41 
 
 3.86 
 
 13 000 
 
 92 
 
 1.12 
 
 .38 
 
 .20 
 
 
 4.06 
 
 2.11 
 
 13 500... 
 
 .71 
 
 .74 
 
 .19 
 
 
 .65 
 
 4.64 
 
 1.05 
 
 14 000 
 
 38 
 
 .19 
 
 .28 
 
 
 
 2.90 
 
 1.05 
 
 14 500 
 
 29 
 
 .23 
 
 .14 
 
 
 
 2.03 
 
 .70 
 
 15 000 
 
 27 
 
 .31 
 
 .05 
 
 .20 
 
 
 2.03 
 
 
 15 500... 
 
 .10 
 
 .04 
 
 .05 
 
 
 
 .58 
 
 .70 
 
 16 000 
 
 22 
 
 .08 
 
 
 
 
 3.19 
 
 .35 
 
 16 500 
 
 13 
 
 
 .05 
 
 
 
 2.03 
 
 
 17 000 
 
 08 
 
 .12 
 
 
 
 
 .58 
 
 
 17 500 
 
 06 
 
 .04 
 
 
 
 
 .87 
 
 
 18 000... 
 
 .05 
 
 .04 
 
 
 
 
 .29 
 
 .35 
 
 18 500 
 
 03 
 
 .08 
 
 
 
 
 
 
 19 000 
 
 02 
 
 
 
 
 
 .29 
 
 
 19 500 
 
 
 
 
 
 
 
 
 20 000 
 
 . . . . .02 
 
 
 
 
 
 .29 
 
 
 20 500... 
 
 .02 
 
 
 
 
 
 .29 
 
 
 21 000 
 
 02 
 
 
 
 
 
 .29 
 
 
 21 500 
 
 02 
 
 
 
 
 
 .29 
 
 
 Lower class limit. The 3,500 class includes values from 3,500 up to but not including 4,000. 
 
1943] 
 
 MILKING SHORTHORN* MII.K RECORDS 
 
 555 
 
 (Table 3 and Fig. 2). This corresponds with what is true generally, 
 since in every breed of milk cows fat percentage is distinctly less 
 variable than milk yield. This is to be expected since fat percentage 
 merely expresses the ratio of milk fat to milk (which might be about 
 the same for either high- or low-producing cows), while milk yield can 
 vary greatly because it is influenced by environmental factors such as 
 feed. Conditions that tend to increase milk yield tend to increase fat 
 yield at the same time, so that the ratio between the two is not appre- 
 ciably changed. 
 
 Mean milk yield was 8,337 pounds and mean fat percentage was 
 3.97. The figure for fat percentage may be said to represent a definite 
 characteristic of the Milking Shorthorn breed, but because milk yield 
 depends so much on environmental factors, a yield of 8,337 pounds 
 should not be assumed to be characteristic. 
 
 The coefficient of correlation between fat percentage and milk 
 yield for all the groups was .217 (Table 4). This means that as fat 
 percentage increases there is a tendency for milk yield to decrease (this 
 is assuming that fat percentage affects yield of milk). 
 
 TABLE 3. MEANS, STANDARD DEVIATIONS, AND COEFFICIENTS OF VARIATION IN 
 FAT PERCENTAGE, MILK YIELD, MILK-FAT YIELD, AND MILK-ENERGY YIELD 
 
 Group 
 
 Fat 
 percentage 
 
 Milk 
 
 Fat 
 
 FCM 
 
 Means 
 
 2x-SL-12 mo. 
 
 3 99 
 
 Ib. 
 8 334 
 
 Ib. 
 331 
 
 Ib. 
 8 299 
 
 2x-SL- < 1 2 mo 
 
 3 97 
 
 8 044 
 
 318 
 
 7 988 
 
 2x-DL-10 mo 
 
 3.97 
 
 7 481 
 
 296 
 
 7 432 
 
 2x-DL- <10 mo. 
 
 ... 4 OS 
 
 7 383 
 
 298 
 
 7 423 
 
 3x-SL-12 mo. . . 
 
 3 88 
 
 11 576 
 
 448 
 
 11 350 
 
 3x-SL- < 1 2 mo 
 
 3 . 93 
 
 9 695 
 
 380 
 
 9 578 
 
 Ml six 
 
 3 97 
 
 8 337 
 
 330 
 
 8 285 
 
 
 
 
 
 
 Standard deviations 
 
 2x-SL-12 mo 
 
 327 
 
 2 079 
 
 81.1 
 
 2 019 
 
 2x-SL- <12 mo. . . ... 
 
 334 
 
 1 758 
 
 69 1 
 
 1 706 
 
 2x-DL-10 mo 
 
 326 
 
 1 745 
 
 68.6 
 
 1 699 
 
 2x-DL- < 10 mo 
 
 373 
 
 1 674 
 
 70.7 
 
 1 695 
 
 3x-SL-12 mo. . 
 
 304 
 
 2 779 
 
 108 6 
 
 2 704 
 
 3x-SL- < 1 2 mo 
 
 288 
 
 2 113 
 
 83.5 
 
 2 064 
 
 All six 
 
 332 
 
 2 167 
 
 84.3 
 
 2 102 
 
 
 
 
 
 
 Coefficients of variation 
 
 2x-SL-12 mo 
 
 . 8.2 
 
 25.0 
 
 24.5 
 
 24.3 
 
 2x-SL- <12 mo. 
 
 84 
 
 21 9 
 
 21 7 
 
 21.4 
 
 2x-DL-10 mo 
 
 8.2 
 
 23.3 
 
 23.2 
 
 22.9 
 
 2x-DL- <10 mo. 
 
 9 2 
 
 22 7 
 
 23 7 
 
 22.8 
 
 3x-SL-12 mo 
 
 7.8 
 
 24.0 
 
 24.2 
 
 23.8 
 
 3x-SL- < 1 2 mo. 
 
 7 3 
 
 21 8 
 
 22 
 
 21 .5 
 
 All six . 
 
 . 8.4 
 
 26.0 
 
 25.5 
 
 25.4 
 
556 
 
 BULLETIN No. 498 
 
 [August, 
 
 TABLE 4. COEFFICIENTS OF CORRELATION BETWEEN FAT PERCENTAGE AND 
 MILK YIELD, FAT YIELD, AND FCM YIELD 
 
 Coefficient of correlation between fat percentage and : 
 
 Group 
 
 Milk yield 
 
 Fat yield 
 
 FCM yield 
 
 2x-SL-12 mo. . 
 
 -.224 .012 
 
 + .107 .013 
 
 027 013 
 
 2x-SL- < 1 2 mo 
 
 -.219 .014 
 
 + .169 .015 
 
 + 012 015 
 
 2x-DL-10 mo. 
 
 -.196 029 
 
 + .159 029 
 
 + 016+ 030 
 
 .' \ - 1 ) I . < 10 mo 
 
 -.138 .030 
 
 + .259 .029 
 
 4- 107 031 
 
 3x-SL-12 mo 
 
 -.1S2 .035 
 
 + .174 .035 
 
 -f.042 .036 
 
 3x-SL- <12 mo. 
 
 -.161 .039 
 
 + .189 .039 
 
 4- 048 040 
 
 All six 
 
 -.217 .008 
 
 + .106 .008 
 
 026+ 009 
 
 
 
 
 
 In Figs. 3 and 4 this trend is shown for two groups 2x-SL-12 
 mo. and 3x-SL- 12 mo. by the slanting lines passing thru the crosses. 
 
 Fig. 2. Percentage frequency distribution curves for fat percentage and 
 milk yield. Crosses indicate means. CV is the coefficient of variation. 
 
1943] 
 
 MILKING SHORTHORN MII.K RKCOKDS 
 
 557 
 
 These lines are valid descriptions of the relation between fat percent- 
 age and milk yield, in so far as that relation can be expressed by a 
 straight line. The coefficient of correlation for the 2x-SL-12 mo. 
 group is .224. The decrease in yield with increasing fat percentage 
 of this group can be determined by dividing the standard deviation of 
 milk yield, 2,079 pounds, by the standard deviation of fat percentage, 
 .327, and multiplying the quotient by the coefficient of correlation. 
 Thus .224 X 2079/.327 equals 1,424 pounds, which represents the de- 
 crease in milk yield for each increase of 1 in fat percentage in this 
 group. For the 3x-SL- 12 mo. group, which has a correlation of .152, 
 the decrease is 1,388 pounds. 
 
 -moo 
 
 -6000 
 
 -ISOOO 
 
 -uoc 
 
 
 
 
 . 
 
 J 
 
 41 4S 
 
 49 
 
 _J_ 
 
 5 
 
 Fig. 3. Each of the 2,585 pairs of records in the 2x-SL-12 mo. groups for 
 fat percentage and milk yield is represented by a dot. The cross indicates 
 the mean fat percentage and mean milk yield, and the straight line passing 
 thru the center of the cross shows the regression of milk yield on fat per- 
 centage (coefficient of correlation, .224). 
 
558 
 
 BULLETIN No. 498 
 
 [Augitst, 
 
 So far as numerical values alone are concerned, it is equally valid 
 to say that as milk yield increases, fat percentage tends to decrease. 
 The extent of this tendency for the 2x-SL-12 mo. group is .224 X 
 .327/2079, or a reduction of .035 in fat percentage for each 1,000 
 pounds increase in milk yield. 
 
 A point of interest in connection with Fig. 3 is the way in which 
 the distribution of the dots is cut off at a more or less straight line 
 near the bottom of the graph. This is due to the entrance requirement 
 which keeps out any record showing less than 5,250 pounds of milk 
 containing up to 4 percent fat or less than 210 pounds of fat in milk 
 containing more than 4 percent fat. If all records were included, a 
 
 1SOOO 
 2/000 
 20000 
 /90OO 
 /8000 
 J7000 
 ASOOO 
 /fOOO 
 /4000 
 
 !*j woo 
 
 V //ooo 
 
 /oooo 
 
 9OOO 
 8000 
 7000 
 ffOOO 
 
 JOOO 
 
 23 of/ 
 
 JtS J7 J9 
 
 4.7 4.9 
 
 S.3 
 
 Fig. 4. Fat percentage and milk yield for the 3x-SL-12 mo. group are 
 shown here in the same way as those for the 2x-SL-12 mo. group are shown 
 in Fig. 3. Coefficient of correlation is .152. 
 
1943] 
 
 MILKING SHORTHORN MILK RECORDS 
 
 559 
 
 symmetrical distribution of milk yield about its mean would probably 
 result, with occasional records running down to 2,000 pounds or even 
 less. In Fig. 4, on the other hand, the dots do not form a straight line 
 across the bottom, indicating that the entrance requirement did not 
 exclude any considerable number of records, probably either because 
 of inherently higher-producing cows in the 3x group, or of more favor- 
 able environmental factors (such as feed supply), or of a combination 
 of inherent and environmental factors. 
 
 Fat percentage and milk-energy yield. Milk-energy yield 
 (FCM) can be estimated very accurately by the formula FCM = AM 
 + 15F, in which M is the actual milk yield in pounds, F is the actual 
 milk- fat yield in pounds, and FCM is the estimated milk-energy yield 
 in pounds of 4-percent milk. One hundred pounds of FCM is equal to 
 about 34 therms (34,000 large calories) and contains about 3.4 pounds 
 of protein regardless of the percent of fat in the original milk. 
 
 /OO 
 30 
 60 
 
 I 6 " 
 
 /a? 
 
 /oo 
 
 80 
 60 
 
 2X.-SL, 
 
 SI /L/C 
 
 /OO 
 8O 
 
 60 
 
 /<to 
 
 /20 
 /OO 
 
 60 
 
 SO 
 
 60 
 
 f.f 
 
 Fig. 5. Regressions of milk yield, milk-fat yield, and FCM yield on fat per- 
 centage were about the same for all six groups. In each case the yield 
 shown by the regression line at 3-percent fat is taken as 100. 
 
560 
 
 BULLETIN No. 498 
 
 [August, 
 
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MILKING SHORTHORN MILK RECORDS 561 
 
 The correlation between fat percentage and FCM is negative for 
 all the records considered together and for the 2x-SL-12 mo. group, 
 while in all other groups it is positive (Table 4). In all cases the cor- 
 relation is small, so that for all practical purposes fat percentage and 
 FCM may be considered independent variables in these records. 
 
 Fat percentage and milk-fat yield. Coefficients of correlation 
 between fat percentage and fat yield are positive for each group of 
 records (Table 4), indicating that as fat percentage increases there is 
 a tendency for milk- fat yield to increase. 
 
 Summary of fat-percentage correlations. A graphical summary 
 of the relation between fat percentage and milk yield, fat yield, and 
 FCM yield is given in Fig. 5. These regression lines, derived from the 
 data of Tables 3 and 4, are plotted on a percentage basis for simplicity 
 of comparison. In each case the yield at 3 percent fat is taken as 100, 
 with the lines covering the range from 3 to 5.5 percent fat. These lines 
 show the tendency of yield to change as fat percentage changes. 
 
 Each of the six groups presents about the same picture. When the 
 3-percent yield is taken as base, the 5.5-percent yield shows that milk 
 yield decreased about 30 percent, milk-fat yield increased about 30 
 percent, and FCM yield stayed about the same. 
 
 These figures are quite consistent with those found in the records 
 of other breeds. The general conclusion is well established that: 
 
 (milk yield decreases 
 fat yield increases 
 FCM yield is unaffected 
 
 Milk yield, fat yield, and FCM yield for the various fat-percentage 
 classes and groups of records are given in Table 5. 
 
 AGE AT CALVING AND MILK YIELD 
 Revision of Age-Correction Factors for Milking Shorthorns 
 
 The "correction" of milk yield for age of cow is a practice of long 
 standing and wide use. One of the purposes of this study was to de- 
 termine the accuracy of the age-correction factors for Milking Short- 
 horns. To do this it was necessary to study the method by which the 
 factors were arrived at and then to see whether that method would 
 give the same answer when applied to the records reported here. 
 
 The average FCM yield by age groups for 4,216 records of Red 
 Danish cows in Denmark is presented in Fig. 6 (these records are 
 comparable to the records of Dairy Herd Improvement Associations). 
 
562 BULLETIN No. 498 [August, 
 
 12 13 14 15 16 17 IS 13 
 
 Fig. 6. This curve shows the origin of the age-yield curve on which the 
 correction factors on page 576 are based. The curve shown above is derived 
 from 4,216 annual records of cows of the Red Danish breed in Denmark. 
 The three points at the right represent a single cow and are omitted in 
 fitting the equation. 
 
 They show the well-known tendency for milk yield to increase as a 
 cow becomes older until it reaches a maximum when the cow is about 
 8 years old, and then to decrease. The records clearly indicate the in- 
 creasing phase. That yield declines after a cow is 8 years old is not so 
 well proved but is assumed to be true. The smooth curve of Fig. 6 
 represents an equation fitted to the observations and assumes that milk 
 production does decline after a certain age. The highest point in this 
 curve is at 9,056 pounds,, which is termed the smoothed maximum 
 yield with age for this population of cows and records. In Fig. 7 this 
 smooth curve is reproduced on a percentage basis, 1 with the point of 
 maximum FCM yield at 100. Records of six other breeds, including 
 the first 1,014 R.M. records of the Milking Shorthorns, are super- 
 imposed on the graph to bring them together for easy comparison. In 
 each case the smoothed maximum is taken as 100. 
 
 It is apparent from Fig. 7 that there are considerable differences 
 
 'The equation of this curve is log y = 2.02057 .487*- 505 ' .00149^*". This 
 means that there are two components to the age-yield relation: one of growth 
 or increase, which decreases at the rate of 50.5 percent (the exponent .505) a 
 year ; the other of senescence or decrease, which increases at the rate of 26.3 
 percent (exponent .263) a year. This equation permits computation of the age- 
 correction factors given on page 576. 
 
1943} 
 
 MILKING SHORTHORN MILK RECORDS 
 
 563 
 
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 SfE 
 
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 3 rt j 
 
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 -* 
 
 'Q^ * S 
 
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 Q/ 4> O I i 
 
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 S 95 8 S 8 S 
 
 (X) PIOIA lunuiiKDw peinoooic p weojej 
 
564 
 
 BULLETIN No. 498 
 
 [August, 
 
 between the records for the various breeds, particularly with refer- 
 ence to the ascending part of the curve, but it is also apparent that the 
 smooth curve will be fairly well adjusted for any one of the breeds 
 when it is shifted either to left or to right, as the case requires. For 
 the Guernsey breed it will fit the data when it is shifted two months to 
 
 //o 
 
 SO 
 
 Fig. 8. Relation of FCM yield to age at calving in Milking Shorthorn cows. 
 Each of the six groups of records is plotted separately according to age at 
 calving. The smooth curve is the same as that of Fig. 7, but is shifted six 
 months to the right. As thus adjusted it forms the basis for the age-correc- 
 tion factors for Milking Shorthorns given on page 576. 
 
 the left; for the Jersey breed recent and trustworthy data indicate 
 that the line needs to be shifted three months to the left. For the 
 Milking Shorthorn breed, on the other hand, it needs to be shifted 
 twelve months to the right. 
 
 This comparison says in effect that the Milking Shorthorn breed 
 matures 15 months later in the function of lactation than the Jersey 
 breed. That Milking Shorthorns should mature later than Jerseys 
 seems consistent with general observation, but that the difference 
 
1943] MILKING SHORTHORN MILK RECORDS 565 
 
 should be 15 months seems extreme. The data in Fig. 8 show clearly 
 that the first 1,014 R.M. records of the breed (up to June 1, 1920), 
 which were used to make up Fig. 7, do not represent the present status 
 of the breed as shown by the records from 1924 to 1938. 
 
 In making up Fig. 8 the first step was to arrive at the smoothed 
 maximum FCM yield for each of the six groups. This was done by 
 fitting the equation FCM = a -f b X age + c X age 2 to the age classes 
 and FCM yields at 5 years and up. The smoothed maximum FCM 
 
 yield for each was as follows: 
 
 Age when 
 
 maximum was Smoothed 
 
 reached maximum FCM 
 
 Group years Ib. 
 
 2x-SL-12mo 10.62 10,228 
 
 2x-SL-<12mo 9.11 9,447 
 
 2x-DL-10mo 8.16 8,910 
 
 2x-DL-<10mo 7.06 8,708 
 
 3x-SL-12mo 9.86 13,161 
 
 3x-SL-<12mo 10.89 10,832 
 
 The exact age at which the maximum is attained by this method 
 is of no particular importance, except for application in its equation 
 to ascertain the smoothed maximum yield. The smoothed maximum 
 yield determined by this method amounts to an age-corrected average. 
 
 The smooth curve in Fig. 8, which seems to fit the dots well, is that 
 of Fig. 7 shifted six months to the right. This indicates that in recent 
 years the breed has matured six months earlier in the milking function 
 than formerly, since according to the earlier records this curve would 
 need to have been shifted twelve months to the right. It seems unlikely 
 that this earlier maturity represents a change in the inherent qualities 
 of the breed; it is more likely that it is a result of change in manage- 
 ment of the cows making R.M. records. 
 
 For a table of age-correction factors for Milking Shorthorns, as 
 revised, see page 576. 
 
 Other Data on the Relation of Age to Yield 
 
 Various data in connection with the relation between age and yield 
 are given in Table 6. Records for cows less than six years old at 
 calving in the 2x-SL-12 mo. group are plotted in Fig. 9 according 
 to age at calving and milk yield. The correlation was .610 (this corre- 
 lation is higher than is usually found). For cows up to six years old 
 milk yield was evidently more closely associated with age than with 
 fat percentage, where the correlation was .224. 
 
566 
 
 BULLETIN No. 498 
 
 [August, 
 
 Influence of age on yield is shown in greater detail in Fig. 10, 
 where data for cows in the 2x-SL-12 mo. group five years old or 
 younger at calving are classified by monthly age intervals. The 3x-SL- 
 12 mo. records also shown in Fig. 10 are not numerous enough to be 
 split into monthly age groups. Both of these curves show that in- 
 
 13000 
 
 am 
 /aoo 
 
 XXXV 
 
 700O 
 6000 
 
 MOO 
 4030 
 
 ft J4- JO -X 42 
 
 /KC AT CAL WHS - 
 
 Fig. 9. Age at calving and milk yield for each of the 2,039 cows under 6 
 years old in the 2x-SL-12 mo. group are indicated by a dot. The cross 
 indicates the means, and the straight line passing thru it shows the regres- 
 sion of milk yield on age at calving. The coefficient of correlation is +.610. 
 The lower line shows the entrance requirement for milk yield. Any dot 
 below this line represents a record qualifying because of its milk-fat record. 
 
1943] MILKING SHORTHORN MILK RECORDS 567 
 
 TABLE 6. EFFECT OF AGE OF Cow ON FAT PERCENTAGE, MILK YIELD, FAT 
 YIELD, AND FCM YIELD 
 
 Group 
 
 Age 
 
 2x-SL- 
 
 2x-SL- 
 
 2x-DL- 
 
 2x-DL- 
 
 3x-SL- 
 
 3x-SL- 
 
 
 12 mo. 
 
 <12 mo. 
 
 10 mo. 
 
 < 10 mo. 
 
 12 mo. 
 
 <12 mo. 
 
 Frequency distribution by percent 
 
 Jr. 1 
 
 .04 
 
 
 
 
 
 
 Sr. 1 
 
 .... 3.56 
 
 1.97 
 
 3.77 
 
 1.08 
 
 .29 
 
 
 Jr. 2 
 
 21.24 
 
 17.18 
 
 20.83 
 
 15.15 
 
 13.33 
 
 9.47 
 
 Sr. 2 
 
 16.87 
 
 14.74 
 
 18.65 
 
 11 .90 
 
 12.17 
 
 8.42 
 
 Jr. 3 
 
 9.83 
 
 8.92 
 
 10.12 
 
 13.42 
 
 6.38 
 
 8.42 
 
 Sr. 3 . . 
 
 7.54 
 
 9.30 
 
 6.15 
 
 7.58 
 
 8.12 
 
 7.72 
 
 Jr. 4 
 
 5 . 38 
 
 6.06 
 
 5.16 
 
 8.01 
 
 6.09 
 
 6.67 
 
 Sr. 4 
 
 5.61 
 
 6.76 
 
 5.16 
 
 7.36 
 
 4.64 
 
 8.07 
 
 5 
 
 8.82 
 
 9.72 
 
 8.73 
 
 9.96 
 
 9.57 
 
 16.14 
 
 6 
 
 7.23 
 
 8.22 
 
 7.74 
 
 8.66 
 
 10.43 
 
 13.68 
 
 7. . 
 
 5.42 
 
 6.67 
 
 6.15 
 
 5.63 
 
 7.83 
 
 8.07 
 
 8 
 
 2 . 79 
 
 4.37 
 
 1.98 
 
 6.28 
 
 8.70 
 
 5.26 
 
 9 
 
 2.40 
 
 2.58 
 
 1.79 
 
 2.16 
 
 5.22 
 
 3.86 
 
 10 
 
 1.55 
 
 1.55 
 
 1.79 
 
 1.08 
 
 2.90 
 
 1.75 
 
 11 
 
 66 
 
 .99 
 
 1.39 
 
 1.08 
 
 2.61 
 
 1.75 
 
 12 . 
 
 .54 
 
 .66 
 
 .40 
 
 .22 
 
 .58 
 
 
 13 
 
 19 
 
 .14 
 
 .20 
 
 .22 
 
 .58 
 
 
 14 
 
 15 
 
 .14 
 
 
 .22 
 
 .29 
 
 .35 
 
 15 
 
 08 
 
 .05 
 
 
 
 .29 
 
 .35 
 
 16 
 
 08 
 
 
 
 
 
 
 17. . 
 
 .04 
 
 
 
 
 
 
 Average fat percentage 
 
 Jr. 1 
 
 4.47 
 
 
 
 
 
 
 Sr. 1 
 
 4.05 
 
 3.94 
 
 3.86 
 
 4.00 
 
 3.89 
 
 
 Jr. 2 
 
 4.02 
 
 4.03 
 
 3.97 
 
 4.12 
 
 3.85 
 
 3.98 
 
 Sr. 2 
 
 3.98 
 
 3.97 
 
 4.00 
 
 4.06 
 
 3.87 
 
 3.98 
 
 Jr. 3 
 
 4.02 
 
 3.97 
 
 3.88 
 
 4.03 
 
 3.98 
 
 4.04 
 
 Sr. 3 . . 
 
 3.97 
 
 3.96 
 
 3.91 
 
 4.01 
 
 3.90 
 
 3.91 
 
 tJ::::::::::::::: 
 
 3.97 
 3.94 
 
 3.93 
 3.93 
 
 4.00 
 3.92 
 
 4.04 
 4.07 
 
 3.91 
 3.97 
 
 3.89 
 4.00 
 
 5 
 
 3.95 
 
 3.95 
 
 3.96 
 
 4.04 
 
 3.87 
 
 3.91 
 
 6 
 
 3.94 
 
 3.91 
 
 3.99 
 
 4.00 
 
 3.87 
 
 3.91 
 
 7. . 
 
 3.88 
 
 3.94 
 
 3.79 
 
 4.02 
 
 3.81 
 
 3.90 
 
 8 
 
 3.95 
 
 3.93 
 
 4.06 
 
 3.97 
 
 3.85 
 
 3.85 
 
 9 
 
 3.88 
 
 3.93 
 
 4.15 
 
 3.96 
 
 3.88 
 
 3.78 
 
 10 
 
 3.87 
 
 3.90 
 
 4.01 
 
 4.17 
 
 3.84 
 
 3.89 
 
 11 
 
 3.87 
 
 3.85 
 
 4.00 
 
 3.81 
 
 3.73 
 
 3.91 
 
 12. . 
 
 3.81 
 
 3.82 
 
 3.98 
 
 3.40 
 
 4.59 
 
 
 13 
 
 3.66 
 
 3.88 
 
 3.47 
 
 3.47 
 
 3.61 
 
 
 14 
 
 3 . 76 
 
 3.32 
 
 
 4.16 
 
 3.47 
 
 3.56 
 
 15 
 
 3.66 
 
 3.71 
 
 
 
 3.36 
 
 3.50 
 
 16 
 
 4.10 
 
 
 
 
 
 
 17 . 
 
 4.17 
 
 
 
 
 
 
 (Table is continued on next page.) 
 
568 BULLETIN No. 498 [August, 
 
 TABLE 6. EFFECT OF AGE OF Cow ON FAT PERCENTAGE, MILK YIELD, FAT 
 YIELD, AND FCM YIELD (Continued) 
 
 Group 
 
 Age 
 
 2x-SL- 
 
 2x-SL- 
 
 2x-DL- 
 
 2x-DL- 
 
 3x-SL- 
 
 3x-SL- 
 
 
 12 mo. 
 
 <12 mo. 
 
 10 mo. 
 
 <10 mo. 
 
 12 mo. 
 
 <12 mo. 
 
 Average pounds of milk 
 
 Jr. 1 
 
 . 4 963 
 
 
 
 
 
 
 Sr. 1 
 
 6 419 
 
 6 515 
 
 6 090 
 
 5 874 
 
 7 605 
 
 
 Jr. 2 
 
 6 883 
 
 6 480 
 
 6 144 
 
 5 893 
 
 9 058 
 
 7 546 
 
 Sr. 2 
 
 7 154 
 
 6 858 
 
 6 492 
 
 5 966 
 
 9 995 
 
 7 983 
 
 Jr. 3 
 
 7 671 
 
 7 177 
 
 7 289 
 
 6 723 
 
 10 227 
 
 8 636 
 
 Sr. 3 . . 
 
 . 8 586 
 
 8 036 
 
 7 462 
 
 7 424 
 
 10 549 
 
 9 264 
 
 Jr. 4 
 Sr. 4 
 
 8 756 
 9 391 
 
 8 370 
 8 963 
 
 7 997 
 8 438 
 
 7 766 
 7 868 
 
 11 190 
 12 073 
 
 9 428 
 9 937 
 
 5 
 
 9 927 
 
 9 216 
 
 9 039 
 
 8 407 
 
 12 391 
 
 10 472 
 
 6 
 
 10 094 
 
 9 202 
 
 8 906 
 
 8 816 
 
 12 482 
 
 10 133 
 
 7. . 
 
 . 10 207 
 
 9 720 
 
 8 935 
 
 8 667 
 
 13 322 
 
 10 980 
 
 8 
 
 10 153 
 
 9 545 
 
 9 288 
 
 8 721 
 
 14 015 
 
 10 683 
 
 9 
 
 10 437 
 
 9 515 
 
 8 090 
 
 8 831 
 
 12 760 
 
 11 648 
 
 10 
 
 10 295 
 
 9 147 
 
 8 651 
 
 8 049 
 
 12 845 
 
 10 146 
 
 11 
 
 11 085 
 
 9 466 
 
 9 644 
 
 7 983 
 
 13 680 
 
 11 644 
 
 12. . 
 
 . 10 575 
 
 9 703 
 
 10 373 
 
 7 244 
 
 11 454 
 
 
 13 
 
 10 447 
 
 8 859 
 
 12 402 
 
 7 230 
 
 14 810 
 
 
 14 
 
 10 662 
 
 10 352 
 
 
 9 032 
 
 12 260 
 
 13 694 
 
 15 
 
 9 256 
 
 8 349 
 
 
 
 16 270 
 
 8 401 
 
 16 
 
 8 653 
 
 
 
 
 
 
 17 
 
 10 273 
 
 
 
 
 
 
 Average pounds of fat 
 
 Jr. 1 
 
 222 
 
 
 
 
 
 
 Sr. 1 
 
 260 
 
 257 
 
 235 
 
 235 
 
 296 
 
 
 Jr. 2 
 
 277 
 
 261 
 
 244 
 
 243 
 
 348 
 
 300 
 
 Sr. 2 
 
 285 
 
 272 
 
 260 
 
 242 
 
 387 
 
 318 
 
 Jr. 3 
 
 308 
 
 285 
 
 283 
 
 271 
 
 407 
 
 349 
 
 Sr. 3 . . 
 
 341 
 
 318 
 
 292 
 
 298 
 
 411 
 
 362 
 
 Jr. 4 
 
 348 
 
 329 
 
 320 
 
 314 
 
 437 
 
 367 
 
 Sr. 4 
 
 370 
 
 352 
 
 331 
 
 320 
 
 479 
 
 397 
 
 5 
 
 392 
 
 364 
 
 358 
 
 340 
 
 479 
 
 409 
 
 6 
 
 398 
 
 360 
 
 355 
 
 353 
 
 483 
 
 396 
 
 7. . 
 
 396 
 
 383 
 
 339 
 
 348 
 
 508 
 
 428 
 
 8 
 
 401 
 
 375 
 
 377 
 
 346 
 
 540 
 
 411 
 
 9 
 
 405 
 
 374 
 
 336 
 
 350 
 
 495 
 
 440 
 
 10 
 
 398 
 
 357 
 
 347 
 
 336 
 
 493 
 
 395 
 
 11 
 
 429 
 
 364 
 
 386 
 
 304 
 
 510 
 
 455 
 
 12. . 
 
 403 
 
 371 
 
 413 
 
 246 
 
 526 
 
 
 13 
 
 382 
 
 344 
 
 430 
 
 251 
 
 535 
 
 
 14 
 
 401 
 
 344 
 
 
 376 
 
 426 
 
 488 
 
 15 
 
 339 
 
 310 
 
 
 
 546 
 
 294 
 
 16 
 
 355 
 
 
 
 
 
 
 17 
 
 428 
 
 
 
 
 
 
 (Table is concluded on next page.) 
 
1943] 
 
 MILKING SHORTHORN MII.K RECORDS 
 
 TABLE 6. EFFECT OF AGE OF Cow ON FAT PERCENTAGE, 
 YIELD, AND FCM YIELD (Concluded) 
 
 569 
 MILK YIELD, FAT 
 
 Group 
 
 Age 
 
 2x-SL- 
 
 2x-SL- 
 
 2x-DL- 
 
 2x-DL- 
 
 3x-SL- 
 
 3x-SL- 
 
 
 12 mo. 
 
 <12 mo. 
 
 10 mo. 
 
 <10 mo. 
 
 12 mo. 
 
 <12 mo. 
 
 Average pounds of FCM 
 
 Jr. 1 
 
 . 5 315 
 
 
 
 
 
 
 Sr. 1 
 
 6 468 
 
 6 461 
 
 5 961 
 
 5 875 
 
 7 482 
 
 
 Jr. 2 
 
 6 908 
 
 6 507 
 
 6 118 
 
 6 002 
 
 8 858 
 
 7 518 
 
 Sr. 2 
 
 7 137 
 
 6 833 
 
 6 497 
 
 6 016 
 
 9 803 
 
 7 963 
 
 Jr. 3.... 
 
 7 688 
 
 7 146 
 
 7 161 
 
 6 754 
 
 10 196 
 
 8 689 
 
 Sr. 3 . 
 
 . 8 549 
 
 7 984 
 
 7 365 
 
 7 440 
 
 10 385 
 
 9 136 
 
 Jr. 4 
 
 8 722 
 
 8 283 
 
 7 999 
 
 7 816 
 
 11 031 
 
 9 276 
 
 Sr. 4 
 
 9 306 
 
 8 865 
 
 8 340 
 
 7 947 
 
 12 014 
 
 9 930 
 
 S 
 
 9 851 
 
 9 146 
 
 8 986 
 
 8 463 
 
 12 141 
 
 10 324 
 
 6 
 
 10 008 
 
 9 081 
 
 8 887 
 
 8 821 
 
 12 238 
 
 9 993 
 
 7. . 
 
 . 10 023 
 
 9 633 
 
 8 659 
 
 8 687 
 
 12 949 
 
 10 812 
 
 8 
 
 10 076 
 
 9 443 
 
 9 370 
 
 8 678 
 
 13 706 
 
 10 438 
 
 9 
 
 10 250 
 
 9 416 
 
 8 276 
 
 8 782 
 
 12 529 
 
 11 259 
 
 10 . 
 
 10 088 
 
 9 014 
 
 8 665 
 
 8 260 
 
 12 533 
 
 9 983 
 
 11 
 
 10 869 
 
 9 246 
 
 9 648 
 
 7 753 
 
 13 122 
 
 11 483 
 
 12. . 
 
 . 10 275 
 
 9 446 
 
 10 344 
 
 6 588 
 
 12 472 
 
 
 13 
 
 9 909 
 
 8 704 
 
 11 411 
 
 6 657 
 
 13 949 
 
 
 14 
 
 10 280 
 
 9 301 
 
 
 9 253 
 
 11 294 
 
 12 798 
 
 15 
 
 8 787 
 
 7 990 
 
 
 
 14 698 
 
 7 770 
 
 16 
 
 8 786 
 
 
 
 
 
 
 17 . 
 
 10 529 
 
 
 
 
 
 
 Average FCM yield as percent of smoothed maximum 
 
 Jr. 1 
 
 52.0 
 
 
 
 
 
 
 Sr. 1 
 
 63 . 2 
 
 68.4 
 
 66.9 
 
 67.5 
 
 56.9 
 
 
 Jr. 2' 
 
 67.5 
 
 68.9 
 
 68.7 
 
 68.9 
 
 67.3 
 
 69.4 
 
 Sr. 2 
 
 69.8 
 
 72.2 
 
 72.9 
 
 69.1 
 
 74.5 
 
 73.5 
 
 Jr. 3.... 
 
 75 . 2 
 
 75.6 
 
 80.4 
 
 77.6 
 
 77.5 
 
 80.2 
 
 Sr. 3 . . 
 
 83.6 
 
 84.5 
 
 82.7 
 
 85.4 
 
 78.9 
 
 84.8 
 
 Jr. 4 
 
 85 . 3 
 
 87.7 
 
 89.8 
 
 89.8 
 
 83.8 
 
 85.6 
 
 Sr. 4 
 
 91.0 
 
 93.8 
 
 93.6 
 
 91.3 
 
 91.3 
 
 91.7 
 
 5 
 
 96.3 
 
 96.8 
 
 100.9 
 
 97.2 
 
 92.3 
 
 95.3 
 
 6 
 
 97.9 
 
 96.1 
 
 99.7 
 
 101.3 
 
 93.0 
 
 92.3 
 
 7. . 
 
 98.0 
 
 102.0 
 
 97.2 
 
 99.8 
 
 98.4 
 
 99.8 
 
 8 
 
 98.5 
 
 100.0 
 
 105.2 
 
 99.7 
 
 104.1 
 
 96.4 
 
 9 
 
 100.2 
 
 99.7 
 
 92.9 
 
 100.9 
 
 95.2 
 
 103.9 
 
 10. . 
 
 98.6 
 
 95.4 
 
 97.3 
 
 94.9 
 
 95.2 
 
 92.2 
 
 11 
 
 ... 106.3 
 
 97.9 
 
 108.3 
 
 89.0 
 
 99.7 
 
 106.0 
 
 12. . 
 
 100.5 
 
 100.0 
 
 116.1 
 
 75.7 
 
 94.8 
 
 
 13 
 
 96.9 
 
 92.1 
 
 128.1 
 
 76.5 
 
 106.0 
 
 
 14 
 
 100.5 
 
 98.5 
 
 
 106.3 
 
 85.8 
 
 118.2 
 
 15 . 
 
 85.9 
 
 84.6 
 
 
 
 111.7 
 
 71.7 
 
 16. . 
 
 85.9 
 
 
 
 
 
 
 17 
 
 102.9 
 
 
 
 
 
 
570 
 
 BULLETIN No. 498 
 
 [August, 
 
 Fig. 10. A detailed picture of the relation between age at calving and FCM 
 yield shows that there are cycles in the age-yield curve. The smooth curves 
 are freehand curves interpolated to show the trend. 
 
 crease in FCM yield occurs in cycles, altho the cycles in the 2x and 3x 
 records do not coincide. For the 2x-SL-12 mo. group the age-yield 
 curve is much steeper from three to four years than it is from two to 
 three years. 
 
 Milk Yield Influenced More by Weight Than by Age 
 
 Altho the requirements for entry in the Record of Merit are based 
 on yield as related to age and altho the use of age-correction factors 
 is very common, it has been fairly well established that it is not the 
 age but the size of the cow that affects her yield. Unfortunately in the 
 records presented here and in many others like them, age is recorded 
 but live weight is not, so that an age-correction system must be used. 
 
 Within certain limits size increases with age, so there is the prob- 
 lem of finding out how much of the cow's increasing yield is due to 
 increased age and how much to increased weight. From records in 
 which both age at calving and live weight within the first 31 days after 
 calving are known, it has been found that age has no appreciable in- 
 fluence on yield independent of live weight, at least for cows up to 
 13 years old, but that live weight has substantially the same very 
 marked effect on yield whether acting with age or independent of age. 
 It seems evident that increased yield with age is due to the increase 
 in live weight with age. It appears then that a system of milk -yield 
 correction based on live weight of the cow as determined within 31 
 
1943] 
 
 MILKING SHORTHORN MILK RECORDS 
 
 571 
 
 days after calving is biologically much sounder than the age -correction 
 system. 
 
 According to the age -correction table, if a Milking Shorthorn 
 calves at 2 years 4 months, the age -correction factor is 1.50. But it is 
 obvious that a well -grown cow at that age will tend to have a better 
 production record than is assumed by this age -correction factor, and 
 an animal not so well grown will tend to have a lower record. 
 
 MONTH OF CALVING AND MILK-ENERGY YIELD 
 
 FCM yields classified according to month of calving show that in 
 general August calvers have the lowest FCM yield and November 
 calvers the highest (Table 7 and Fig. 11). Other data relating to month 
 of year in which cows calved are also given in Table 7. 
 
 Figure 11 also brings out conspicuously the difference between 
 
 /2000 
 
 //ooo 
 
 /oooo 
 
 $000 
 
 
 x 
 
 8000 
 
 7000 
 
 6000 
 
 
 or 
 
 Fig. 11. November calvers had the highest FCM yield and August calvers 
 the lowest. Note also the superiority of the 3x records over 2x records. 
 
572 
 
 BULLETIN- No. 498 
 
 [August, 
 
 TABLE 7. EFFECT OF MONTH OF CALVING ON MILK YIELD, FAT YIELD, FCM 
 YIELD, AND FAT PERCENTAGE 
 
 Month of cat 
 
 Group 
 
 Vlng 2x-SL- 
 12 mo. 
 
 2x-SL- 2x-DL- 
 <12 mo. 10 mo. 
 
 2x-DL- 
 <10 mo. 
 
 3x-SL- 
 12 mo. 
 
 3x-SL- 
 <12 mo. 
 
 Frequency distribution by percent 
 
 
 9 . 48 
 
 9.58 
 8.40 
 9.86 
 8.50 
 6.85 
 5.16 
 5.40 
 7.56 
 8.50 
 11.08 
 8.36 
 10.75 
 
 11.11 
 13.89 
 5.95 
 5.16 
 2.78 
 2.56 
 3.97 
 8.93 
 11.90 
 12.30 
 10.52 
 10.91 
 
 14.50 
 12.99 
 12.77 
 9.96 
 2.81 
 2.60 
 1.52 
 4.33 
 6.28 
 12.12 
 9.96 
 10.17 
 
 11.01 
 6.96 
 10.14 
 9.57 
 7.54 
 6.67 
 5.80 
 5.22 
 9.28 
 11.59 
 5.22 
 11.01 
 
 11.93 
 9.82 
 7.37 
 6.32 
 3.86 
 3.86 
 3.86 
 7.72 
 9.82 
 12.28 
 11.93 
 11.23 
 
 February 
 
 8 . 70 
 
 March 
 
 10.14 
 
 
 9.05 
 
 May 
 
 7.31 
 
 June 
 
 5.42 
 
 July 
 
 6.15 
 
 August 
 
 7.31 
 
 
 7 97 
 
 
 9 . 25 
 
 November 
 
 9.28 
 
 December 
 
 9.94 
 
 
 
 Average pounds of milk 
 
 
 . 8 306 
 
 8 020 
 8 101 
 8 097 
 7 931 
 8 022 
 8 024 
 7 697 
 7 839 
 8 006 
 8 175 
 8 219 
 8 168 
 
 7 128 
 7 372 
 7 717 
 7 465 
 6 763 
 7 426 
 7 390 
 7 104 
 7 219 
 7 614 
 8 148 
 7 838 
 
 7 946 
 7 442 
 7 222 
 7 212 
 7 035 
 7 187 
 6 836 
 6 844 
 7 267 
 7 786 
 7 307 
 6 999 
 
 12 260 
 10 962 
 12 061 
 11 622 
 11 055 
 10 629 
 11 186 
 10 212 
 10 747 
 11 730 
 12 950 
 12 449 
 
 10 202 
 10 194 
 10 285 
 10 447 
 9 326 
 9 119 
 8 343 
 8 951 
 9 064 
 9 655 
 9 418 
 10 097 
 
 
 8 509 
 
 March 
 
 8 468 
 
 April 
 
 8 379 
 
 May 
 
 8 427 
 
 June 
 
 8 500 
 
 uly 
 
 7 998 
 
 
 7 806 
 
 September 
 
 8 210 
 
 October 
 
 8 237 
 
 
 ... . 8 509 
 
 
 8 489 
 
 
 
 Average pounds of fat 
 
 
 334 
 
 317 
 321 
 313 
 310 
 312 
 317 
 307 
 312 
 321 
 327 
 329 
 321 
 
 285 
 289 
 296 
 289 
 267 
 287 
 284 
 286 
 286 
 306 
 325 
 308 
 
 326 
 297 
 291 
 288 
 268 
 283 
 262 
 284 
 300 
 320 
 293 
 279 
 
 478 
 432 
 466 
 452 
 428 
 420 
 423 
 410 
 410 
 454 
 489 
 476 
 
 397 
 397 
 396 
 396 
 360 
 349 
 328 
 356 
 360 
 382 
 381 
 395 
 
 February 
 
 336 
 
 March 
 
 335 
 
 April 
 
 331 
 
 May 
 
 331 
 
 June 
 
 338 
 
 July 
 
 313 
 
 
 , 308 
 
 September 
 
 329 
 
 October 
 
 , 329 
 
 
 340 
 
 December , 
 
 335 
 
 
 
 Average pounds of FCM 
 
 January 
 
 . 8 
 
 332 
 
 7 
 
 963 
 
 7 
 
 126 
 
 8 
 
 068 
 
 12 
 
 074 
 
 10 036 
 
 February 
 
 8 
 
 444 
 
 8 
 
 055 
 
 7 
 
 284 
 
 7 
 
 432 
 
 10 
 
 865 
 
 10 033 
 
 March 
 
 8 
 
 412 
 
 7 
 
 934 
 
 7 
 
 527 
 
 7 
 
 254 
 
 11 
 
 814 
 
 10 054 
 
 April 
 
 8 
 
 317 
 
 7 
 
 822 
 
 7 
 
 321 
 
 7 
 
 205 
 
 11 
 
 429 
 
 10 119 
 
 May 
 
 8 
 
 336 
 
 7 
 
 889 
 
 6 
 
 710 
 
 
 
 834 
 
 10 
 
 842 
 
 9 130 
 
 June 
 
 8 
 
 470 
 
 7 
 
 965 
 
 7 
 
 275 
 
 7 
 
 120 
 
 10 
 
 552 
 
 8 883 
 
 July 
 
 7 
 
 894 
 
 7 
 
 684 
 
 7 
 
 216 
 
 6 
 
 664 
 
 10 
 
 819 
 
 8 257 
 
 August 
 
 7 
 
 742 
 
 7 
 
 816 
 
 7 
 
 132 
 
 6 
 
 998 
 
 10 
 
 235 
 
 8 920 
 
 September 
 
 8 
 
 219 
 
 8 
 
 017 
 
 7 
 
 178 
 
 7 
 
 407 
 
 10 
 
 449 
 
 9 026 
 
 October 
 
 8 
 
 230 
 
 . 8 
 
 175 
 
 7 
 
 636 
 
 7 
 
 914 
 
 11 
 
 502 
 
 9 592 
 
 November 
 
 8 
 
 504 
 
 8 
 
 223 
 
 8 
 
 134 
 
 7 
 
 318 
 
 12 
 
 515 
 
 9 482 
 
 December 
 
 8 
 
 421 
 
 8 
 
 082 
 
 7 
 
 755 
 
 
 
 985 
 
 12 
 
 120 
 
 9 964 
 
 (Table is concluded on next page.) 
 
1943] MILKING SHORTHORN MILK RECORDS 573 
 
 TABLE 7. EFFECT OF MONTH OF CALVING ON MILK YIELD, FAT YIELD, FCM 
 YIELD, AND FAT PERCENTAGE (Concluded) 
 
 Group 
 
 Month of calving 2 x-SL- 2x-SL- 2x-DL- 2x-DL- 3x-SL- 3x-SL- 
 
 12 mo. <12 mo. 10 mo. <10 mo. 12 mo. <12 mo. 
 
 Average fat percentage 
 
 January 
 
 4.02 
 
 3.95 
 
 4.00 
 
 4.10 
 
 3.90 
 
 3.89 
 
 February 
 
 3.95 
 
 3.96 
 
 3.93 
 
 4.00 
 
 3.94 
 
 3.90 
 
 March 
 
 3.96 
 
 3.87 
 
 3.84 
 
 4.03 
 
 3.86 
 
 3.85 
 
 April 
 
 3.95 
 
 3.91 
 
 3.86 
 
 4.00 
 
 3.89 
 
 3.79 
 
 May 
 
 3.93 
 
 3.89 
 
 3.95 
 
 3.81 
 
 3.87 
 
 3.86 
 
 June 
 
 3.98 
 
 3.95 
 
 3.86 
 
 3.94 
 
 3.95 
 
 3.83 
 
 July 
 
 3.92 
 
 3.98 
 
 3.85 
 
 3.84 
 
 3.79 
 
 3.92 
 
 August 
 
 3.95 
 
 3.98 
 
 4.02 
 
 4.14 
 
 4.01 
 
 3.97 
 
 September 
 
 4.00 
 
 4.01 
 
 3.96 
 
 4.13 
 
 3.82 
 
 3.97 
 
 October 
 
 4.00 
 
 4.00 
 
 4.02 
 
 4.11 
 
 3.87 
 
 3.96 
 
 November 
 
 4.00 
 
 4.00 
 
 3.99 
 
 4.01 
 
 3.78 
 
 4.04 
 
 December 
 
 3.94 
 
 3.93 
 
 3.93 
 
 3.99 
 
 3.82 
 
 3.91 
 
 2x and 3x records, showing to what an extent 3x records exceed 2x 
 records. The difference between 12-mo. records and <12-mo. records 
 is also quite evident. 
 
 FREQUENCY OF MILKING AND MILK-ENERGY YIELD 
 
 To see how Milking Shorthorn cows respond to the favorable condi- 
 tions accompanying three and four milkings daily, the SL-12 mo. rec- 
 ords were divided into groups of 2, 3, or 4 milkings and average actual 
 FCM yield and smoothed maximum FCM yield determined. There were 
 only six records in the 4x group (R.M. Nos. 4181, 4182, 5465, 8160, 
 8162, and 8164) and for these six records age-corrected FCM yield is 
 used as the smoothed maximum. The average records were: 
 
 Actual FCM Smoothed 
 
 yield maximum FCM 
 Group Ib. Ib. 
 
 2x-SL-12 mo 8,334 10,228 
 
 3x-SL-12 mo 11,576 13,161 
 
 4x-SL-12 mo 15,834 17,815 
 
 Taking 100 as the base for the 2x group, the Milking Shorthorn 
 records compare as follows with the standards of the Bureau of Dairy 
 Industry and Holstein-Friesian Association of America: 
 
 Standard of Standard of i^-n. CJ ., 
 
 : ,. , Milking Shorthorns 
 
 Bureau of Holstein- 
 
 Dairy Friesian Actual Smoothed 
 
 Daily milkings Industry Association average maximum 
 
 2 100 100 100 100 
 
 3 124 125 139 129 
 
 4 154 150 190 174 
 
574 BULLETIN No. 498 [August, 
 
 These figures indicate that Milking Shorthorns respond to the more 
 favorable conditions accompanying three and four milkings daily with 
 greater yields than would be expected from the standards given. This 
 is especially true for four milkings daily, but the number of such 
 records is, of course, too small to prove this point. 
 
 SUMMARY 
 
 Because milk records for Milking Shorthorn cows had never been 
 analyzed in the same way as those for other breeds, data from Volumes 
 9 to 23 (1924-1938) of the Milking Shorthorn Year Book were col- 
 lected and studied. The records were studied as a whole and in groups 
 according to number of milkings daily, length of calving interval, and 
 length of record. Only records which included age of cow at calving, 
 length of record, milk-fat yield, and fat percentage in addition to milk 
 yield were studied. Milk-energy yield was computed by the formula 
 FCM = A X pounds of milk + 15 X pounds of fat. 
 
 For the 6,311 records the average yield was 8,337 pounds of milk, 
 330 pounds of fat, and 8,285 pounds of FCM, and the average fat 
 percentage was 3.97. The subgroups differed greatly in average milk 
 yield, milk- fat yield, and FCM yield, but differed very little in average 
 fat percentage. For the records as a whole, the correlation between fat 
 percentage and milk yield was .217; between fat percentage and fat 
 yield, + .106; and between fat percentage and FCM yield, .026 
 (not significant). Similar correlations were found in each of the sub- 
 groups. When the change in yield between 3.0 percent fat and 5.5 per- 
 cent fat was expressed by a straight line, milk yield showed a decrease 
 of about 30 percent, fat yield increased about 30 percent, and FCM 
 showed very little change. 
 
 These records afforded an opportunity to check the age-correction 
 factors previously used for Milking Shorthorns, which were based on 
 records of the breed up to June 1, 1920. The records reported here 
 show a distinct shift toward earlier maturity, amounting to 6 months ; 
 and the age-correction factors need to be adjusted accordingly. There 
 is no way of knowing whether this earlier maturity represents a 
 change in the dairy qualities of the breed or a change in management 
 of the cows. Actually age correction is probably simply an indirect 
 allowance for live weight since weight increases with age. A system 
 
1943] MILKING SHORTHORX MILK RECORDS 575 
 
 of milk-yield correction based on live weight would be biologically 
 more sound than an age-correction system, at least for cows less than 
 13 years old. 
 
 The season in which a cow calved had an appreciable effect on 
 FCM yield. In general August calvers had the lowest yield and No- 
 vember calvers had the highest. 
 
 Certain of the records were studied to discover the difference 
 between FCM yields of cows milked three times a day and of cows 
 milked twice a day. The records of a typical group showed that cows 
 milked three times a day exceeded in yield those milked twice a day 
 by 39 percent. The standard for dairy cows of the Bureau of Dairy 
 Industry is that cows milked three times a day should outyield those 
 milked twice a day by 24 percent, so it appears that Milking Short- 
 horns respond well to the more favorable conditions associated with 
 three milkings daily. 
 
576 BULLETIN No. 498 
 
 TABLE OF AGE-CORRECTION FACTORS FOR 
 MILKING SHORTHORNS 
 
 Find in the table the greatest age which is not greater than the 
 age of the cow at calving. Opposite to this is the multiplier factor 
 which can be used to determine the age-corrected yield of the animal. 
 
 A af Correction A aa Correction A Correction 
 
 AgC factor Age factor Ag * factor 
 
 l/r.mo.d. yr. mo. d. yr. mo. d. 
 
 2-0-6 1.61 2-10-4 1.35 4-9-26 1.09 
 
 2-0-15 1.60 2-10-19 1.34 4-11-19 1.08 
 
 2-0-24 1.59 2-11-4 1.33 5-1-21 1.07 
 
 2-1-3 1.58 2-11-21 1.32 5-4-2 1.06 
 
 2-1-13 1.57 3-0-7 1.31 5-6-18 1.05 
 
 2-1-23 1.56 3-0-27 1.30 5-9-18 1.04 
 
 2-2-3 1.55 3-1-16 1.29 6-1-2 1.03 
 
 2-2-13 1.54 3-2-5 1.28 6-5-12 1.02 
 
 2-2-23 1.53 3-2-25 1.27 6-11-9 1.01 
 
 2-3-3 1.52 3-3-16 1.26 7-9-15 1.00 
 
 2-3-13 1.51 3-4-7 1.25 10-1-28 1.01 
 
 2-3-23 1.50 3-4-28 1.24 11-2-8 1.02 
 
 2-4-3 1.49 3-5-20 1.23 11-10-17 1.03 
 
 2-4-13 1.48 3-6-12 1.22 12-5-5 1.04 
 
 2-4-24 1.47 3-7-8 1.21 12-10-21 1.05 
 
 2-5-5 1.46 3-8-6 1.20 13-3-11 1.06 
 
 2-5-16 1.45 3-9-5 1.19 13-7-21 1.07 
 
 2-5-28 1 .44 3-10- 4 1 . 18 13-11-19 1 .08 
 
 2-6-10 1.43 3-11-3 1.17 14-3-0 1.09 
 
 2-6-24 1.42 4-0-2 1.16 14-6-11 1.10 
 
 2-7-8 1.41 4-1-5 1.15 14-9-7 1.11 
 
 2-7-22 1.40 4-2-14 1.14 15-0-0....: 1.12 
 
 2-8-6 1.39 4-3-23 1.13 15-2-16 1.13 
 
 2-8-21... 1.38 4-5-3 1.12 15-4-28 1.14 
 
 2-9-5 1.37 4-6-15 1.11 15-7-6 1.15 
 
 2-9-20 1.36 4-8-5 1.10 
 
 This table may be used as it is for Brown Swiss cows. For Ayr- 
 shires it is necessary to increase the actual age at calving by 2 months, 
 for Holsteins 6 months, for Guernseys 8 months, and for Jerseys 9 
 months. Thus a Milking Shorthorn or a Brown Swiss calving when 
 2 years, 2 months, and 3 days old would have an age-correction factor 
 of 1.55. For an Ayrshire the factor would be 1.49, for a Holstein it 
 would be 1.40, for a Guernsey 1.36, and for a Jersey 1.34. 
 
 The average of a large number of age-corrected yields, selected 
 at random, may be expected to equal the average of a large number of 
 actual yields of eight-year-old cows selected at random. The age- 
 corrected yield of an individual cow, however, is not usually the ex- 
 pected yield of that cow when eight years old. 
 
 3500 8-43 26370 
 
AUTHOR INDEX 
 
 577 
 
 AUTHOR INDEX 
 
 1. BULL, S. ( and RUSK, H. P. Ef- 
 
 fect of Exercise on Quality of 
 Beef 105-120 
 
 2. BURLISON, W. L. See FUELLE- 
 
 MAN 9 
 
 3. CARD, L. E. See WILCOX 22 
 
 4. CARROLL, W. E., and ROBERTS, 
 
 E. Crossbreeding in Swine: 
 Does It Offer an Effective 
 Method for the Improvement 
 of Market Hogs? 121-136 
 
 5. CASE, H.C. M. See JOHNSTON 12 
 
 6. DUNCAN, G. H. See NEVENS 16 
 
 7. EKSTROM, V. A. Marketing the 
 
 Illinois Peach Crop 273-320 
 
 8. EKSTROM, V. A. See LLOYD 14 
 
 9. FUELLEMAN, R. F., BURLISON, 
 
 W. L., and KAMMLADE, W. G. 
 Bromegrass and Bromegrass 
 Mixtures, Culture and Utiliza- 
 tion 473-192 
 
 10. GAINES, W. L. An Analysis of 
 
 Milking Shorthorn Milk 
 Records 549-576 
 
 11. HUELSEN, W. A. Yield of Sweet 
 
 Corn in Relation to Distance 
 and Rate of Planting 33-104 
 
 12. JOHNSTON, P. E., and CASE, 
 
 H. C. M. Twelve Years of 
 Farm Accounts in Illinois. . 185-272 
 
 13. KAMMLADE, W. G. See FUELLE- 
 
 MAN 9 
 
 14. LLOYD, J. W., and EKSTROM, V. 
 
 A. Marketing the Illinois 
 Apple Crop 493-548 
 
 15. LOTT, R. V. Effect of Nitrate of 
 
 Soda on Development of the 
 Halehaven Peach 321-384 
 
 16. NEVENS, W. B., and DUNCAN, 
 
 G. H. Yields of Corn Hybrids 
 Harvested for Silage: And 
 Methods to Determine Best 
 Time to Harvest 385-412 
 
 17. PRUCHA, M.J., and TRACY, P. H. 
 
 Bacteriological and Practical 
 Aspects of Paper Containers 
 for Milk 413-472 
 
 18. ROBERTS, E. See CARROLL 4 
 
 19. RUSK, H. P. See BULL 1 
 
 20. SMITH, G. D. Illinois Loess, Var- 
 
 iations in Its Properties and 
 Distribution: a Pedologic In- 
 terpretation 137-184 
 
 21. TRACY, P. H. See PRUCHA 17 
 
 22. WILCOX, R. H., and CARD, L. 
 
 E. Poultry Costs and Profits. . 1-32 
 
578 INDEX 
 
 INDEX 
 
 PAGE 
 
 APPLE CROP, MARKETING THE ILLINOIS; PRESENT PRACTICES AND 
 
 HISTORICAL REVIEW 493-547 
 
 summary 546-547 
 
 See also Contents in bulletin 495 
 
 Apples, grades 510-516 
 
 BEEF, EFFECT OF EXERCISE ON QUALITY OF BEEF 105-120 
 
 summary and conclusions 119-1 20 
 
 See also Contents in bulletin 106 
 
 Beef, grades, effect of exercise on 112 
 
 Bromegrass 
 
 grazing tests 485 
 
 pasture for sheep 486-487 
 
 BROMEGRASS AND BROMEGRASS MIXTURES; CULTURE AND UTILIZATION. . . .473-491 
 
 summary and conclusions 491 
 
 See also Contents in bulletin 474 
 
 Cattle, beef, exercise effect on quality of beef 105-120 
 
 Cattle, dairy, milk records, an analysis of milking shorthorn 549-576 
 
 Chickens, see Poultry 
 
 CORN, SWEET, YIELD OF, IN RELATION TO DISTANCE AND RATE OF 
 
 PLANTING 33-104 
 
 literature cited 104 
 
 recommendations. 103-104 
 
 summary and conclusions 102-103 
 
 See also Contents in bulletin 34 
 
 Corn hybrids, characteristics compared with open-pollinated varieties 
 
 tested for forage to be ensiled 394 
 
 CORN HYBRIDS HARVESTED FOR SILAGE, YIELDS OF: AND METHODS 
 
 TO DETERMINE BEST TIME TO HARVEST 385-412 
 
 literature cited 400-401 
 
 summary and conclusions 399^400 
 
 See also Contents in bulletin 386 
 
 FARM ACCOUNTS IN ILLINOIS, TWELVE YEARS OF 187-271 
 
 summary and conclusions 250-256 
 
 See also Contents in bulletin 188 
 
 Farm income, Illinois accounting farms, see FARM ACCOUNTS IN ILLINOIS 
 Farm prices, Illinois accounting farms, see FARM ACCOUNTS IN ILLINOIS 
 
 HALEHAVEN PEACH, EFFECT OF NITRATE OF SODA ON DEVELOPMENT 
 
 OF THE 321-384 
 
 literature cited 381-384 
 
 summary and conclusions 380-381 
 
 See also Contents in bulletin 322 
 
 Hogs, see Swine 
 
 Land use on Illinois accounting farms 218-225 
 
 LOESS, ILLINOIS VARIATIONS IN ITS PROPERTIES AND DISTRIBUTION: 
 
 A PEDOLOGIC INTERPRETATION 137-184 
 
 literature cited 183-184 
 
 summary and conclusions 182-183 
 
 See also Contents in bulletin 138 
 
 MARKETING THE ILLINOIS APPLE CROP; PRESENT PRACTICES AND 
 
 HISTORICAL REVIEW 493-547 
 
 summary 546-547 
 
 See also Contents in bulletin. . 495 
 
INDEX 579 
 
 PAGE 
 
 MARKETING THE ILLINOIS PEACH CROP 273-320 
 
 summary and conclusions 31 1-312 
 
 See also Contents in bulletin 274 
 
 MILK, BACTERIOLOGICAL AND PRACTICAL ASPECTS OF PAPER 
 
 CONTAINERS FOR 413-472 
 
 literature cited 472 
 
 summary and conclusions 469-471 
 
 See also Contents in bulletin 414 
 
 MILK RECORDS, AN ANALYSIS OF MILKING SHORTHORN 549-576 
 
 summary 574-575 
 
 See also Contents in bulletin 550 
 
 PAPER CONTAINERS FOR MILK, BACTERIOLOGICAL AND PRACTICAL 
 
 ASPECTS OF 413-472 
 
 literature cited 472 
 
 summary and conclusions 469-471 
 
 See also Contents in bulletin 414 
 
 PEACH CROP, MARKETING THE ILLINOIS 273-320 
 
 summary and conclusions 311-312 
 
 See also Contents in bulletin 274 
 
 Peaches 
 
 Halehaven peach, effect of nitrate of soda on development 321-384 
 
 marketing in wartime 312-315 
 
 production in Illinois 275-279 
 
 varieties grown in Illinois 279-280 
 
 POULTRY COSTS AND PROFITS 1-32 
 
 See Contents in bulletin 2 
 
 Silage, corn hybrids harvested for 385-412 
 
 Soil, loess in Illinois 137-184 
 
 SWINE, CROSSBREEDING IN: DOES IT OFFER AN EFFECTIVE METHOD 
 
 FOR THE IMPROVEMENT OF MARKET HOGS? 121-136 
 
 bibliography 136 
 
 summary and conclusions 134-135 
 
 See also Contents in bulletin. . . . 122