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Standards of Weight and Height for Holstein Heifers1
Standards of Weight and Height for Holstein Heifers 1 A. J. H E I N R I C H S and G. L. H A R G R O V E Department of Dairy and Animal Science The Pennsylvania State University University Park 16802 ABSTRACT
To develop a modern appraisal of growth of Holstein dairy heifers, height at withers and heart girth (body weight) data were collected for 5723 heifers representing 163 commercial Holstein dairy herds from October 1983 through May 1985. Quadratic regression equations of height and weight on age were computed for each herd. Estimated weight and height of heifers at 24 mo from these equations were found to be correlated with herd variables such as herd average milk production and age at first calving. Means and standard deviations for height and weight were determined for each age (1 through 24 mo). Third order regressions on age were fitted to the means to describe height and weight. Estimated height (cm) and weight (kg) at 6, 12, 18, and 24 mo were 101.0, 167.2; 117.6, 299.1; 127.4, 420.6; and 132.7, 516.2. A subset of data containing heifers in 89 herds that had a herd average milk production of >7264 kg were also fitted to third order regression on age. Weight and height of dairy heifers are moderately larger in herds with >7264 kg average milk production. Based on the entire data set, commercial Holstein herds in Pennsylvania have heifers somewhat larger than those used to develop National Research Council recommendations. INTRODUCTION
Growth defined as maturation of the reproductive system, as well as an increase in b o d y size and weight, is affected by many
Received September 8, 1986. Accepted December 1, 1986. 1Authorized for publication as Paper Number 7470 in the Journal Series of the Pennsylvania Agricultural Experiment Station. 1987 J Dairy Sci 70:653--660
factors such as genetics, nutrition, and management. Every animal has an inherent mature body size toward which it grows at a genetically controlled rate (2), accelerated or delayed by environmental factors resulting in little influence on mature body size (1, 3, 8). Swanson (19) defined the optimal growth pattern for dairy heifers as that regimen that will develop their full lactation potential at the desired age and with minimum expense. Other studies have indicated no real advantage for rapidly grown dairy heifers over those maintained on more restricted growth patterns (8, 18); however, some discussion is made on the amount of restriction (20). In comparison of heifer growth rates, one must be careful not to suggest that increased rate of growth will increase productivity of the animal in later years, as results of studies have been inconsistent in this area (10, 17, 21). Considering rearing costs and first lactation milk income, Hayes (9) found that calving at 24 mo or less was most profitable, which necessitates well-grown heifers. Growth rate of heifers should be moderate without noticeable fattening (20). Growth rates of dairy heifers in experiment station herds were used to establish growth standards reported previously (4, 6, 11, 15). Comparison of early growth standards (6, 15) with later ones (4, 11) indicates that from the 1920's to the 1950's mature size and recommended growth rates of dairy heifers increased. Growth standards being used currently (13) are those developed in the 1930's and 1950's, despite questioning as to their representation of the population (19) and examples showing growth rates that exceed the standards (7, 14). These current standards represent one to three experiment station herds (4, 11, 15), inbred lines (11), and measurements obtained over a period of 10 (15), 20 (4), or 30 (11) years. These standards, or averages of growth, may have been biased by the unique management or genetic lines on the respective research farms. The applicability of a standard for growth developed in one herd and used on
653
654
HEINRICHS AND HARGROVE
another herd depends on the degree of similarity between the herds in respect to conditions that affect initial weight and rate of growth (11). Therefore, it was deemed necessary to study growth patterns in a wider variety of herds than has been done previously, allowing the results to be used across a wider range of the population. The objectives of this research were 1) to develop a modern appraisal of the growth of Holstein dairy heifers on commercial dairy farms, 2) to examine the association of growth of heifers with herd variables such as production and age at calving, and 3) to compare growth of heifers in herds above average in milk production with heifers in the entire sample. MATERIALS AND METHODS
Data were collected from commercial Holstein dairy herds throughout Pennsylvania as part of an extension survey and edited for suitability for this research. Measurements collected from fall 1983 through spring 1985 included heart girth as an estimate of weight (5), height at withers, and date of birth for all heifers. As previously shown (16), weight tapes are accurate to -+ 7% of actual weights in heifers and thus fall within the range of normal variation with a single measurement. It also has been shown that during pregnancy increased weight is associated with an increase in heart girth, so the usual relationship between actual weight and estimated weight from heart girth measurement is not upset by pregnancy (5). Tapes calibrated in weight were used on all heifers. Height was measured with a vertical standard calibrated to .635 cm and equipped with a crossbar with level. Selected data reflecting the overall management of the farm during the previous 12 mo were collected. Size of milking herd, herd average milk, calving interval, number calves born, number calves dead at birth, and number calves dead before 1 yr of age were recorded. For herds not on production testing (n = 16), average milk production was estimated by determining the amount of milk contained in the bulk tank, dividing by the number of cows milking, and multiplying by 305. Age at measurement was calculated to the nearest whole month. Herds retained for this research were required to have a m i n i m u m of 10 heifers measured at less than 25 mo of age, Journal of Dairy Science Vol. 70, No. 3, 1987
with 2 less than or equal to 8 mo of age, and 2 greater than or equal to 20 mo of age. A quadratic regression equation on age was computed for height and for weight for each herd. From these equations, estimated height and weight at 24 mo of age were computed. Three herds were deleted from the data set because their 24-mo height or weight estimates were beyond 3 standard deviations ( S D ) f r o m the mean for all herds (other herd variables were within 1 SD from the mean). The final data set contained measurements from 148 different herds throughout 33 counties in Pennsylvania. Seven of these herds were measured two times and four of these herds were measured three times. These multiple measurements were made at least 10 mo apart and were counted as new herds each time. In a further step to delete unusual data, possibly resulting from birth date errors, 6 animals having weight or height measurements greater than 4 standard deviations from the mean weight or height for their age were eliminated. The final data set consisted of 5723 heifers from 163 herds. Means and standard deviations of animals in the final data set measured at each age (1 through 24 too) were determined. Third order regression on age was fitted to these means to describe the population. Similar regressions were fitted to the 24 observations determined as mean plus one standard deviation and to the 24 observations determined as mean minus one standard deviation to establish a range around the population estimate. Product-moment correlations were calculated between pairs of herd variables, including estimated weight and height at 24 mo, herd average production, and average age at first calving. In order to examine further the growth parameters associated with herd production, herds with average milk production greater than 7264 kg were analyzed as a subset of the original data. Of the original 163 herds, 89 herds (54.6%) were retained in this data set. Means and standard deviations were determined for this subset of data and utilized to develop regression equations in the same manner as was done for the entire data set. RESULTS A N D DISCUSSION
A summary of the general herd characteristics is in Table 1. Herds represent a wide range of
655
HEIFER GROWTH STANDARDS TABLE 1. Information concerning herds used in the data set. Item
nI
Number of cows Herd average milk, kg Average calving interval, mo Average age first calving, mo No. calves born, past 12 mo 2 No. calves born dead, past 12 mo 2 No. calves died, past 12 mo 3
161 161 143 145 142 142 141
Mean
SD 32.5 1024.1 .7 2.1 36.8 2.9
58.8 7311.7 13.1 26.4 61.2 3.1 2.5
Range 21--230 4551--9398 11.0--15.2 23.0--36.0 10--259 0-21
3.0
0-18
i Data from 163 herds, but not every report contained all items. 2 Males and females. 3 Predominantly females.
f e e d i n g a n d m a n a g e m e n t c o n d i t i o n s as well as a v a r i e t y o f l o c a t i o n s a n d t e r r a i n s in P e n n s y l v a n i a . Weight and height m e a n s and standard d e v i a t i o n s f o r t h e f i n a l d a t a set are in T a b l e 2 b y m o n t h o f age. T h e n u m b e r o f a n i m a l s m e a s u r e d at a given age ( m o ) a n d s t a n d a r d d e v i a t i o n s are similar to o t h e r p r e v i o u s d a t a sets
(4, 11, 15). T h e p r e s e n t d a t a set, h o w e v e r , r e p r e s e n t s d i f f e r e n t a n i m a l s a t e a c h age, w h e r e a s previous reports were based on multiple meas u r e m e n t s o f t h e s a m e a n i m a l s a t d i f f e r e n t ages. T h e m e a n s f o r e a c h m o n t h o f age ( T a b l e 2) were fitted to a third order regression e q u a t i o n o n age f o r w e i g h t a n d f o r h e i g h t . T h e r e s u l t i n g
TABLE 2. Average weights and heights of heifers by age in all herds.:
Age
Number of animals
Weight
(mo) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Height
(kg) 142 218 255 296 287 306 299 295 242 232 209 258 234 235 214 272 228 283 228 257 207 202 172 152
(cm)
"X
SD
.~
SD
62.1 82.1 99.0 122.8 144.4 168.6 191.2 209.0 231.4 255.9 278.8 302.5 316.8 343.6 368.4 380.1 400.3 419.8 436.0 448.1 477.5 495.6 499.8 515.2
9.1 14.3 16.1 23.1 26.9 25.9 31.3 32.7 39.6 42.2 44.4 41.5 46.3 52.6 54.9 56.8 62.2 61.2 60.0 66.7 62.1 71.3 78.1 67.2
80.1 85.6 89.7 93.4 96.9 101.1 104.6 107.2 110.6 112.7 115.5 117.9 119.7 122.0 122.7 124.4 126.0 127.2 128.7 129.1 130.7 132.0 132.4 132.1
3.6 4.4 4.3 5.4 5.6 5.4 5.6 5.7 6.0 5.5 5.4 4.8 4.9 5.2 5.8 5.5 5.2 5_3 5.0 5.0 4.9 5.1 5.4 5.0
1 Data from 163 herds. Journal of Dairy Science Vol. 70, No. 3, 1987
656
HEINRICHS AND H A R G R O V E
TABLE 3. Regression parameter estimates for weight and height for all herds. Dependent
Regression coefficients
variable
Intercept
Linear
Quadratic
Weight Mean Mean + 1 SD Mean - 1 SD
40.274* * 46.461"* 34.088**
19.870" * 23.779** 15.962"*
.285 * .237 t .333*
Height Mean Mean + 1 SD M e a n - 1 SD
75.413"* 78.767** 72.060**
5.153"* 5.733** 4.573**
R 2
Cubic
-.0119 ** -.0120" -.0119"
-.158"* -,203"* --.112"*
>. 99 >.99 >.99
.00177** .00279** .00074
>.99 >.99 >.99
*P<.05. **P<.01. tp<.IO.
TABLE 4. Correlations involving herd variabilities. 1 Variables 1. 2. 3. 4.
1
Herd average p ro duction Average age at first calving Estimated weight at 24 mo Estimated height at 24 mo
-.22* .34* * .41 * *
2
3
-.30"* -.17"
.40* *
Data from 163 herds. *P<.05. **P<.01.
TABLE 5. I n f o r m a t i o n concerning herds with > 7 2 6 4 kg herd average mi l k yield. Item
nt
Mean
Number of cows Herd average milk, kg Average calving interval, mo Average age first calving, mo No. calves born, past 12 mo 2 No. calves born dead, past 12 mo 2 No. calves died, past 12 mo 3
89 89 76 79 75
57.8 8055.9 13.0 26.0 60.4
26.8 542.4 .7 1.9 28.5
75 74
3.2 2.1
2.5 2.4
1 Data from 89 herds, b u t n o t every report contained all items. 2 Males and females. 3 P r e d o m i n a n t l y females. Jour nal o f Dairy Science Vol. 70, No. 3, 1987
SD
Range 21-135 7264-9398 12.0--15.0 23.0--31.0 21-161 0-12 0-13
HEIFER GROWTH STANDARDS
657
TABLE 6. Average weights and heights of heifers by age in herds with >7264 kg herd average milk yield. 1
Age
Number of animals
Weight
(mo)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Height
(kg)
79 120 167 165 185 199 186 178 153 144 129 166 114 145 136 165 147 165 150 161 133 125 105 86
62.9 83.9 100.9 126.7 145.3 171.0 195.5 211.0 236.8 264.7 286.8 305.7 332.0 353.5 375.6 386.4 411.0 429.9 443.4 462.6 491.2 515.6 516.9 525.9
~
(cm)
SD
X
SD
9.1 14.1 15.8 23,2 27.3 25.1 30.5 30.1 40.0 42.9 42.5 41,5 46.5 56.5 56.6 56.3 62.0 64.5 59.4 59.3 59.8 67.0 75.8 66.3
81.0 86.5 90.2 94.4 97.4 102.0 105.5 107.9 111,4 113.9 116.7 118.5 120.9 122,4 124.1 125.3 126.8 128.2 129.5 130.2 131.5 133.2 133.8 132.8
3.1 4.1 4.2 5.1 5.6 5.4 5.4 5.3 5.9 5.1 4.5 4.5 4.8 5.7 5.5 4.8 5.1 5.3 4.7 4.3 4.9 4.8 4.6 4.6
1 Data from 89 herds.
TABLE 7. Regression parameter estimates for weight and height for herds with >7264 kg herd average milk yield. Dependent
Regression coefficients
variable
Intercept
Linear
Quadratic
Weight Mean Mean + 1 SD M e a n - 1 SD
40.957** 47.027** 34.886**
20.181" 23.948* 16.415"
.312" .292 .332 t
Height Mean Mean + 1 SD M e a n - 1 SD
76.163 * * 79.211"* 73.115"*
5.159"* 5.734** 4.585
-.157** --.200** -.113"*
Cubic
--.0126"* -.0137" -.0114" .00174"* .00268** .00081
Ra
>.99 >.99 >.99 >.99 >.99 >.99
*P<.05. * *P<.01.
fP<.10.
Journal of Dairy Science Vol. 70, No. 3, 1987
ox
o
T A B L E 8. C o m p a r i s o n s of w e i g h t and h e i g h t values w i t h p r e v i o u s d a t a sets.
t~ Source PSU 3 < Age 0 Z
R a g s d a l e (15)
Davis a n d H a t h a w a y (4)
(too)
Matthews and F o h r m a n (11 )1
Predicted all herds 2
Predicted selected herds 4
60.4 102.1 167.2 233.5 299.1 362.1 420.6 472.6 516.2
61.4 104.0 170.6 238.7 306.3 371.5 432.0 486.0 531.3
Weight (kg)
0
~o 0o ,q
1 3 6 9 12 15 18 21 24
50.8 87.6 161.2 231.1 286.9 338.7 383.6 432.2 485.3
. . . 97.6 181.1 257.9 319.6 . .. 419.5 521.6
54.8 98.1 181.5 258.9 319.4 367.2 413.0 465.3 506.1
1
77.7
871
8912
6 9 12 15 18 21 24
100.8 110.5 116.8 121.7 125.2 128.5 131.3
103.4 113.1 119.5 ... 128.3 . . . 133.3
1 E s t i m a t e d s t a n d a r d s f r o m T a b l e 3 o f r e f e r e n c e (11), e x c e p t the 2 4 m o e s t i m a t e is f r o m r e f e r e n c e (11) Table 5. a Data f r o m 163 herds. s The P e n n s y l v a n i a S t a t e University. 4 Data f r o m 89 h e r d s w i t h > 7 2 6 4 kg h e r d average m i l k yield.
E -r > Z >
H e i g h t (cm)
3
Z ~0
80.4 89.5 l O l .0 11o.3 117.6 123.2 127.4 13o.5 132.7
81.2 90.3 l O l .8 111.2 118.5 124.1 128.4 131.5 133.7
0 0 <
659
HEIFER GROWTH STANDARDS coefficients and p o r t i o n of variance attributable to the m o d e l (R 2) are in Table 3. In o r d e r to establish a confidence range around the f i t t e d line, separate third order regressions were fitted to the 24 means plus their respective standard deviations and to the 24 means minus their standard deviations. This was done for weight and height, and these results are also in Table 3. Correlations involving herd variables of herd average milk p r o d u c t i o n , average age at first calving, estimated weight at 24 mo, and estim a t e d height at 24 m o are in Table 4. These data support the positive association b e t w e e n heifer growth and herd p r o d u c t i o n as previously r e p o r t e d (12). Estimated weight and height are negatively correlated with average age at first calving. I n f o r m a t i o n concerning general herd characteristics of herds with herd average production > 7 2 6 4 kg are in Table 5, and the weight and height means and standard deviations are in Table 6. Third order regressions on age were fitted for this subset as were done for the original data set. Coefficients and R 2 values are in Table 7. A l t h o u g h the raw means (weight and height) and the f i t t e d regression lines for the selected herds were generally higher than for the w h o l e data set, the differences were n o t large. Table 8 is presented to compare predicted height and weight values f r o m our two data sets with previous data sets. Weights in b o t h present data sets are larger at 1 and 3 too, indicating a possible increase in birth weight and i m p r o v e d early nutrition. Weight is greater at 18 to 24 m o in the present data sets, indicating an increase in mature weight as w o u l d be predicted f r o m an increase in weight at an early age (2). The range b e t w e e n 3 and 18 mo appears to indicate a shift in husbandry practices on commercial herds f r o m that practiced on the research herds used for earlier data. Specific notable managem e n t differences are the e x t e n d e d weaning age and accelerated nutrition regimen on the e x p e r i m e n t station herds (11). Smaller weight gains during this period m a y be m o r e beneficial to later p r o d u c t i o n than overfeeding younger animals (17). The comparison of height values suggests a general shift toward slightly taller animals in the current data. In summary, heifer growth f o u n d on commercial dairy farms is different than that presented in previous studies. Weight and height
at 1 and 3 m o have increased over the past 30 yr. A p o r t i o n of this increase may be due to an increased emphasis in the artificial insemination industry for size and stature of bulls. The most obvious differences f r o m previous standards are in the prepubertal period. Decreasing average age at first calving nearer to 24 mo is an imp o r t a n t m a n a g e m e n t practice for which the dairy farmer should strive and justifies the m a i n t e n a n c e of desirable growth rates of r e p l a c e m e n t heifers. ACKNOWLEDGMENTS
Sincere appreciation is e x t e n d e d to the m a n y c o u n t y agents who helped in collection of heifer data as part of an extension and e d u c a t i o n program. The authors also wish to thank J. B. C o o p e r and Y. A. Akin for assistance in data analysis. The financial support provided by Agway, Inc., Syracuse, NY, is gratefully acknowledged.
REFERENCES
1 Blackmore, D. W., L . . D . McGilliard, and J. L. Lush. 1958. Genetic relation between body measurements at three ages in Holsteins. J. Dairy Sci. 41 : 1045. 2 Brody, S. 1945. Bioenergetics and growth. Reinhold Publ. Corp., New York, NY. 3 Crichton, J. A., J. N. Aitken, and A. W. Boyne. 1959. The effect of plane of nutrition during rearing on growth, production, reproduction and health of dairy cattle. II. Growth to maturity. Anita. Prod. 2:45. 4 Davis, H. P., and I. L. Hathaway. 1956. Comparative measurements of Holsteins, Ayrshire, Guernsey, and Jersey females from birth to seven years. Nebraska Agric. Exp. Stn. Res. Bull. 179. 5 Davis, H. P., W. W. Swett, and W. R. Harvey. 1961. Relations of heart girth to weight in Holsteins and Jerseys. Nebraska Agric. Exp. Stn. Res. Bull. 194. 6 Eckles, C. H., and T. W. Gullickson. 1931. Nutrient requirements for normal growth of dairy cattle. J. Agric. Res. 42:603. 7 Gardner, R. W., J. D. Schuh, and L. G. Vargus. 1977. Accelerated growth and early breeding of Holstein heifers. J. Dairy Sci. 60:1941. 8 Hansson, A. 1956. Influence of rearing intensity on body development and milk production. Proc. Br. Soc. Animal. Prod. 37:252. 9 Hayes, J. W. 1975. Effects of age at first calving of Holstein heifers on dollar returns through first lactation and on lifetime performance. M.S. thesis, The Pennsylvania State Univ., University Park. 10 Holtz, E. W., R. E. Erb, and A. S. Hodgson. 1961. Relationship between rate of gain from birth to six months of age and subsequent yields of dairy cows. J. Dairy Sci. 44:672. Journal of Dairy Science Vol. 70, No. 3, 1987
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HEINRICHS AND HARGROVE
11 Matthews, C. A., and M. H. Fohrman. 1954. Beltsville growth standards for Holstein cattle. US Dept. Agric. Tech. Bull. 1099. 12 Miller, R. H., and L. D. McGilliard. 1959. Relations between weight at first calving and milk production during the first lactation. J. Dairy Sci. 42: 1932. 13 National Research Council. 1978. Nutrient requirements of dairy cattle. 5th rev. ed. Natl. Acad. Sci., Washington, DC. 14 Owen, F. G., and L. L. Larson. 1982. A simplified liquid feeding program for calves. J. Dairy Sci. 65:1350. 15 Ragsdale, A. C. 1934. Growth standards for dairy cattle. Missouri Agric. Exp. Sin. Bull. 336 16 Ragsdale, A. C., and S. Brody. 1935. Estimating live weights in dairy cattle. Missouri Agric. Exp.
Journal of Dairy Science Vol. 70, No. 3, 1987
Stn. Bull. 354. 17 Sejrsen, K., J. T. Huber, H. A. Tucker, and R. M. Akers. 1982. Influence of nutrition on mammary development in pre- and postpubertal heifers. J. Dairy Sci. 65:793. 18 Swanson, E. W. 1960. Effect o f rapid growth with fattening of dairy heifers on their lactational ability. J. Dairy Sci. 43:377. 19 Swanson, E. W. 1967. Optimum growth patterns for dairy cattle. J. Dairy Sci. 50:244. 20 Swanson, E. W. 1971. Feed energy requirements for different rates of growth of dairy heifers. J. Dairy Sci. 54:217. 21 Wilk, J. C., C. W. Young, and C. L. Cole. 1963. Genetic and phenotypic relationships between certain body measurements and first lactation milk production in dairy cattle. J. Dairy Sci. 46:1273.
To develop a modern appraisal of growth of Holstein dairy heifers, height at withers and heart girth (body weight) data were collected for 5723 heifers representing 163 commercial Holstein dairy herds from October 1983 through May 1985. Quadratic regression equations of height and weight on age were computed for each herd. Estimated weight and height of heifers at 24 mo from these equations were found to be correlated with herd variables such as herd average milk production and age at first calving. Means and standard deviations for height and weight were determined for each age (1 through 24 mo). Third order regressions on age were fitted to the means to describe height and weight. Estimated height (cm) and weight (kg) at 6, 12, 18, and 24 mo were 101.0, 167.2; 117.6, 299.1; 127.4, 420.6; and 132.7, 516.2. A subset of data containing heifers in 89 herds that had a herd average milk production of >7264 kg were also fitted to third order regression on age. Weight and height of dairy heifers are moderately larger in herds with >7264 kg average milk production. Based on the entire data set, commercial Holstein herds in Pennsylvania have heifers somewhat larger than those used to develop National Research Council recommendations. INTRODUCTION
Growth defined as maturation of the reproductive system, as well as an increase in b o d y size and weight, is affected by many
Received September 8, 1986. Accepted December 1, 1986. 1Authorized for publication as Paper Number 7470 in the Journal Series of the Pennsylvania Agricultural Experiment Station. 1987 J Dairy Sci 70:653--660
factors such as genetics, nutrition, and management. Every animal has an inherent mature body size toward which it grows at a genetically controlled rate (2), accelerated or delayed by environmental factors resulting in little influence on mature body size (1, 3, 8). Swanson (19) defined the optimal growth pattern for dairy heifers as that regimen that will develop their full lactation potential at the desired age and with minimum expense. Other studies have indicated no real advantage for rapidly grown dairy heifers over those maintained on more restricted growth patterns (8, 18); however, some discussion is made on the amount of restriction (20). In comparison of heifer growth rates, one must be careful not to suggest that increased rate of growth will increase productivity of the animal in later years, as results of studies have been inconsistent in this area (10, 17, 21). Considering rearing costs and first lactation milk income, Hayes (9) found that calving at 24 mo or less was most profitable, which necessitates well-grown heifers. Growth rate of heifers should be moderate without noticeable fattening (20). Growth rates of dairy heifers in experiment station herds were used to establish growth standards reported previously (4, 6, 11, 15). Comparison of early growth standards (6, 15) with later ones (4, 11) indicates that from the 1920's to the 1950's mature size and recommended growth rates of dairy heifers increased. Growth standards being used currently (13) are those developed in the 1930's and 1950's, despite questioning as to their representation of the population (19) and examples showing growth rates that exceed the standards (7, 14). These current standards represent one to three experiment station herds (4, 11, 15), inbred lines (11), and measurements obtained over a period of 10 (15), 20 (4), or 30 (11) years. These standards, or averages of growth, may have been biased by the unique management or genetic lines on the respective research farms. The applicability of a standard for growth developed in one herd and used on
653
654
HEINRICHS AND HARGROVE
another herd depends on the degree of similarity between the herds in respect to conditions that affect initial weight and rate of growth (11). Therefore, it was deemed necessary to study growth patterns in a wider variety of herds than has been done previously, allowing the results to be used across a wider range of the population. The objectives of this research were 1) to develop a modern appraisal of the growth of Holstein dairy heifers on commercial dairy farms, 2) to examine the association of growth of heifers with herd variables such as production and age at calving, and 3) to compare growth of heifers in herds above average in milk production with heifers in the entire sample. MATERIALS AND METHODS
Data were collected from commercial Holstein dairy herds throughout Pennsylvania as part of an extension survey and edited for suitability for this research. Measurements collected from fall 1983 through spring 1985 included heart girth as an estimate of weight (5), height at withers, and date of birth for all heifers. As previously shown (16), weight tapes are accurate to -+ 7% of actual weights in heifers and thus fall within the range of normal variation with a single measurement. It also has been shown that during pregnancy increased weight is associated with an increase in heart girth, so the usual relationship between actual weight and estimated weight from heart girth measurement is not upset by pregnancy (5). Tapes calibrated in weight were used on all heifers. Height was measured with a vertical standard calibrated to .635 cm and equipped with a crossbar with level. Selected data reflecting the overall management of the farm during the previous 12 mo were collected. Size of milking herd, herd average milk, calving interval, number calves born, number calves dead at birth, and number calves dead before 1 yr of age were recorded. For herds not on production testing (n = 16), average milk production was estimated by determining the amount of milk contained in the bulk tank, dividing by the number of cows milking, and multiplying by 305. Age at measurement was calculated to the nearest whole month. Herds retained for this research were required to have a m i n i m u m of 10 heifers measured at less than 25 mo of age, Journal of Dairy Science Vol. 70, No. 3, 1987
with 2 less than or equal to 8 mo of age, and 2 greater than or equal to 20 mo of age. A quadratic regression equation on age was computed for height and for weight for each herd. From these equations, estimated height and weight at 24 mo of age were computed. Three herds were deleted from the data set because their 24-mo height or weight estimates were beyond 3 standard deviations ( S D ) f r o m the mean for all herds (other herd variables were within 1 SD from the mean). The final data set contained measurements from 148 different herds throughout 33 counties in Pennsylvania. Seven of these herds were measured two times and four of these herds were measured three times. These multiple measurements were made at least 10 mo apart and were counted as new herds each time. In a further step to delete unusual data, possibly resulting from birth date errors, 6 animals having weight or height measurements greater than 4 standard deviations from the mean weight or height for their age were eliminated. The final data set consisted of 5723 heifers from 163 herds. Means and standard deviations of animals in the final data set measured at each age (1 through 24 too) were determined. Third order regression on age was fitted to these means to describe the population. Similar regressions were fitted to the 24 observations determined as mean plus one standard deviation and to the 24 observations determined as mean minus one standard deviation to establish a range around the population estimate. Product-moment correlations were calculated between pairs of herd variables, including estimated weight and height at 24 mo, herd average production, and average age at first calving. In order to examine further the growth parameters associated with herd production, herds with average milk production greater than 7264 kg were analyzed as a subset of the original data. Of the original 163 herds, 89 herds (54.6%) were retained in this data set. Means and standard deviations were determined for this subset of data and utilized to develop regression equations in the same manner as was done for the entire data set. RESULTS A N D DISCUSSION
A summary of the general herd characteristics is in Table 1. Herds represent a wide range of
655
HEIFER GROWTH STANDARDS TABLE 1. Information concerning herds used in the data set. Item
nI
Number of cows Herd average milk, kg Average calving interval, mo Average age first calving, mo No. calves born, past 12 mo 2 No. calves born dead, past 12 mo 2 No. calves died, past 12 mo 3
161 161 143 145 142 142 141
Mean
SD 32.5 1024.1 .7 2.1 36.8 2.9
58.8 7311.7 13.1 26.4 61.2 3.1 2.5
Range 21--230 4551--9398 11.0--15.2 23.0--36.0 10--259 0-21
3.0
0-18
i Data from 163 herds, but not every report contained all items. 2 Males and females. 3 Predominantly females.
f e e d i n g a n d m a n a g e m e n t c o n d i t i o n s as well as a v a r i e t y o f l o c a t i o n s a n d t e r r a i n s in P e n n s y l v a n i a . Weight and height m e a n s and standard d e v i a t i o n s f o r t h e f i n a l d a t a set are in T a b l e 2 b y m o n t h o f age. T h e n u m b e r o f a n i m a l s m e a s u r e d at a given age ( m o ) a n d s t a n d a r d d e v i a t i o n s are similar to o t h e r p r e v i o u s d a t a sets
(4, 11, 15). T h e p r e s e n t d a t a set, h o w e v e r , r e p r e s e n t s d i f f e r e n t a n i m a l s a t e a c h age, w h e r e a s previous reports were based on multiple meas u r e m e n t s o f t h e s a m e a n i m a l s a t d i f f e r e n t ages. T h e m e a n s f o r e a c h m o n t h o f age ( T a b l e 2) were fitted to a third order regression e q u a t i o n o n age f o r w e i g h t a n d f o r h e i g h t . T h e r e s u l t i n g
TABLE 2. Average weights and heights of heifers by age in all herds.:
Age
Number of animals
Weight
(mo) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Height
(kg) 142 218 255 296 287 306 299 295 242 232 209 258 234 235 214 272 228 283 228 257 207 202 172 152
(cm)
"X
SD
.~
SD
62.1 82.1 99.0 122.8 144.4 168.6 191.2 209.0 231.4 255.9 278.8 302.5 316.8 343.6 368.4 380.1 400.3 419.8 436.0 448.1 477.5 495.6 499.8 515.2
9.1 14.3 16.1 23.1 26.9 25.9 31.3 32.7 39.6 42.2 44.4 41.5 46.3 52.6 54.9 56.8 62.2 61.2 60.0 66.7 62.1 71.3 78.1 67.2
80.1 85.6 89.7 93.4 96.9 101.1 104.6 107.2 110.6 112.7 115.5 117.9 119.7 122.0 122.7 124.4 126.0 127.2 128.7 129.1 130.7 132.0 132.4 132.1
3.6 4.4 4.3 5.4 5.6 5.4 5.6 5.7 6.0 5.5 5.4 4.8 4.9 5.2 5.8 5.5 5.2 5_3 5.0 5.0 4.9 5.1 5.4 5.0
1 Data from 163 herds. Journal of Dairy Science Vol. 70, No. 3, 1987
656
HEINRICHS AND H A R G R O V E
TABLE 3. Regression parameter estimates for weight and height for all herds. Dependent
Regression coefficients
variable
Intercept
Linear
Quadratic
Weight Mean Mean + 1 SD Mean - 1 SD
40.274* * 46.461"* 34.088**
19.870" * 23.779** 15.962"*
.285 * .237 t .333*
Height Mean Mean + 1 SD M e a n - 1 SD
75.413"* 78.767** 72.060**
5.153"* 5.733** 4.573**
R 2
Cubic
-.0119 ** -.0120" -.0119"
-.158"* -,203"* --.112"*
>. 99 >.99 >.99
.00177** .00279** .00074
>.99 >.99 >.99
*P<.05. **P<.01. tp<.IO.
TABLE 4. Correlations involving herd variabilities. 1 Variables 1. 2. 3. 4.
1
Herd average p ro duction Average age at first calving Estimated weight at 24 mo Estimated height at 24 mo
-.22* .34* * .41 * *
2
3
-.30"* -.17"
.40* *
Data from 163 herds. *P<.05. **P<.01.
TABLE 5. I n f o r m a t i o n concerning herds with > 7 2 6 4 kg herd average mi l k yield. Item
nt
Mean
Number of cows Herd average milk, kg Average calving interval, mo Average age first calving, mo No. calves born, past 12 mo 2 No. calves born dead, past 12 mo 2 No. calves died, past 12 mo 3
89 89 76 79 75
57.8 8055.9 13.0 26.0 60.4
26.8 542.4 .7 1.9 28.5
75 74
3.2 2.1
2.5 2.4
1 Data from 89 herds, b u t n o t every report contained all items. 2 Males and females. 3 P r e d o m i n a n t l y females. Jour nal o f Dairy Science Vol. 70, No. 3, 1987
SD
Range 21-135 7264-9398 12.0--15.0 23.0--31.0 21-161 0-12 0-13
HEIFER GROWTH STANDARDS
657
TABLE 6. Average weights and heights of heifers by age in herds with >7264 kg herd average milk yield. 1
Age
Number of animals
Weight
(mo)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Height
(kg)
79 120 167 165 185 199 186 178 153 144 129 166 114 145 136 165 147 165 150 161 133 125 105 86
62.9 83.9 100.9 126.7 145.3 171.0 195.5 211.0 236.8 264.7 286.8 305.7 332.0 353.5 375.6 386.4 411.0 429.9 443.4 462.6 491.2 515.6 516.9 525.9
~
(cm)
SD
X
SD
9.1 14.1 15.8 23,2 27.3 25.1 30.5 30.1 40.0 42.9 42.5 41,5 46.5 56.5 56.6 56.3 62.0 64.5 59.4 59.3 59.8 67.0 75.8 66.3
81.0 86.5 90.2 94.4 97.4 102.0 105.5 107.9 111,4 113.9 116.7 118.5 120.9 122,4 124.1 125.3 126.8 128.2 129.5 130.2 131.5 133.2 133.8 132.8
3.1 4.1 4.2 5.1 5.6 5.4 5.4 5.3 5.9 5.1 4.5 4.5 4.8 5.7 5.5 4.8 5.1 5.3 4.7 4.3 4.9 4.8 4.6 4.6
1 Data from 89 herds.
TABLE 7. Regression parameter estimates for weight and height for herds with >7264 kg herd average milk yield. Dependent
Regression coefficients
variable
Intercept
Linear
Quadratic
Weight Mean Mean + 1 SD M e a n - 1 SD
40.957** 47.027** 34.886**
20.181" 23.948* 16.415"
.312" .292 .332 t
Height Mean Mean + 1 SD M e a n - 1 SD
76.163 * * 79.211"* 73.115"*
5.159"* 5.734** 4.585
-.157** --.200** -.113"*
Cubic
--.0126"* -.0137" -.0114" .00174"* .00268** .00081
Ra
>.99 >.99 >.99 >.99 >.99 >.99
*P<.05. * *P<.01.
fP<.10.
Journal of Dairy Science Vol. 70, No. 3, 1987
ox
o
T A B L E 8. C o m p a r i s o n s of w e i g h t and h e i g h t values w i t h p r e v i o u s d a t a sets.
t~ Source PSU 3 < Age 0 Z
R a g s d a l e (15)
Davis a n d H a t h a w a y (4)
(too)
Matthews and F o h r m a n (11 )1
Predicted all herds 2
Predicted selected herds 4
60.4 102.1 167.2 233.5 299.1 362.1 420.6 472.6 516.2
61.4 104.0 170.6 238.7 306.3 371.5 432.0 486.0 531.3
Weight (kg)
0
~o 0o ,q
1 3 6 9 12 15 18 21 24
50.8 87.6 161.2 231.1 286.9 338.7 383.6 432.2 485.3
. . . 97.6 181.1 257.9 319.6 . .. 419.5 521.6
54.8 98.1 181.5 258.9 319.4 367.2 413.0 465.3 506.1
1
77.7
871
8912
6 9 12 15 18 21 24
100.8 110.5 116.8 121.7 125.2 128.5 131.3
103.4 113.1 119.5 ... 128.3 . . . 133.3
1 E s t i m a t e d s t a n d a r d s f r o m T a b l e 3 o f r e f e r e n c e (11), e x c e p t the 2 4 m o e s t i m a t e is f r o m r e f e r e n c e (11) Table 5. a Data f r o m 163 herds. s The P e n n s y l v a n i a S t a t e University. 4 Data f r o m 89 h e r d s w i t h > 7 2 6 4 kg h e r d average m i l k yield.
E -r > Z >
H e i g h t (cm)
3
Z ~0
80.4 89.5 l O l .0 11o.3 117.6 123.2 127.4 13o.5 132.7
81.2 90.3 l O l .8 111.2 118.5 124.1 128.4 131.5 133.7
0 0 <
659
HEIFER GROWTH STANDARDS coefficients and p o r t i o n of variance attributable to the m o d e l (R 2) are in Table 3. In o r d e r to establish a confidence range around the f i t t e d line, separate third order regressions were fitted to the 24 means plus their respective standard deviations and to the 24 means minus their standard deviations. This was done for weight and height, and these results are also in Table 3. Correlations involving herd variables of herd average milk p r o d u c t i o n , average age at first calving, estimated weight at 24 mo, and estim a t e d height at 24 m o are in Table 4. These data support the positive association b e t w e e n heifer growth and herd p r o d u c t i o n as previously r e p o r t e d (12). Estimated weight and height are negatively correlated with average age at first calving. I n f o r m a t i o n concerning general herd characteristics of herds with herd average production > 7 2 6 4 kg are in Table 5, and the weight and height means and standard deviations are in Table 6. Third order regressions on age were fitted for this subset as were done for the original data set. Coefficients and R 2 values are in Table 7. A l t h o u g h the raw means (weight and height) and the f i t t e d regression lines for the selected herds were generally higher than for the w h o l e data set, the differences were n o t large. Table 8 is presented to compare predicted height and weight values f r o m our two data sets with previous data sets. Weights in b o t h present data sets are larger at 1 and 3 too, indicating a possible increase in birth weight and i m p r o v e d early nutrition. Weight is greater at 18 to 24 m o in the present data sets, indicating an increase in mature weight as w o u l d be predicted f r o m an increase in weight at an early age (2). The range b e t w e e n 3 and 18 mo appears to indicate a shift in husbandry practices on commercial herds f r o m that practiced on the research herds used for earlier data. Specific notable managem e n t differences are the e x t e n d e d weaning age and accelerated nutrition regimen on the e x p e r i m e n t station herds (11). Smaller weight gains during this period m a y be m o r e beneficial to later p r o d u c t i o n than overfeeding younger animals (17). The comparison of height values suggests a general shift toward slightly taller animals in the current data. In summary, heifer growth f o u n d on commercial dairy farms is different than that presented in previous studies. Weight and height
at 1 and 3 m o have increased over the past 30 yr. A p o r t i o n of this increase may be due to an increased emphasis in the artificial insemination industry for size and stature of bulls. The most obvious differences f r o m previous standards are in the prepubertal period. Decreasing average age at first calving nearer to 24 mo is an imp o r t a n t m a n a g e m e n t practice for which the dairy farmer should strive and justifies the m a i n t e n a n c e of desirable growth rates of r e p l a c e m e n t heifers. ACKNOWLEDGMENTS
Sincere appreciation is e x t e n d e d to the m a n y c o u n t y agents who helped in collection of heifer data as part of an extension and e d u c a t i o n program. The authors also wish to thank J. B. C o o p e r and Y. A. Akin for assistance in data analysis. The financial support provided by Agway, Inc., Syracuse, NY, is gratefully acknowledged.
REFERENCES
1 Blackmore, D. W., L . . D . McGilliard, and J. L. Lush. 1958. Genetic relation between body measurements at three ages in Holsteins. J. Dairy Sci. 41 : 1045. 2 Brody, S. 1945. Bioenergetics and growth. Reinhold Publ. Corp., New York, NY. 3 Crichton, J. A., J. N. Aitken, and A. W. Boyne. 1959. The effect of plane of nutrition during rearing on growth, production, reproduction and health of dairy cattle. II. Growth to maturity. Anita. Prod. 2:45. 4 Davis, H. P., and I. L. Hathaway. 1956. Comparative measurements of Holsteins, Ayrshire, Guernsey, and Jersey females from birth to seven years. Nebraska Agric. Exp. Stn. Res. Bull. 179. 5 Davis, H. P., W. W. Swett, and W. R. Harvey. 1961. Relations of heart girth to weight in Holsteins and Jerseys. Nebraska Agric. Exp. Stn. Res. Bull. 194. 6 Eckles, C. H., and T. W. Gullickson. 1931. Nutrient requirements for normal growth of dairy cattle. J. Agric. Res. 42:603. 7 Gardner, R. W., J. D. Schuh, and L. G. Vargus. 1977. Accelerated growth and early breeding of Holstein heifers. J. Dairy Sci. 60:1941. 8 Hansson, A. 1956. Influence of rearing intensity on body development and milk production. Proc. Br. Soc. Animal. Prod. 37:252. 9 Hayes, J. W. 1975. Effects of age at first calving of Holstein heifers on dollar returns through first lactation and on lifetime performance. M.S. thesis, The Pennsylvania State Univ., University Park. 10 Holtz, E. W., R. E. Erb, and A. S. Hodgson. 1961. Relationship between rate of gain from birth to six months of age and subsequent yields of dairy cows. J. Dairy Sci. 44:672. Journal of Dairy Science Vol. 70, No. 3, 1987
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HEINRICHS AND HARGROVE
11 Matthews, C. A., and M. H. Fohrman. 1954. Beltsville growth standards for Holstein cattle. US Dept. Agric. Tech. Bull. 1099. 12 Miller, R. H., and L. D. McGilliard. 1959. Relations between weight at first calving and milk production during the first lactation. J. Dairy Sci. 42: 1932. 13 National Research Council. 1978. Nutrient requirements of dairy cattle. 5th rev. ed. Natl. Acad. Sci., Washington, DC. 14 Owen, F. G., and L. L. Larson. 1982. A simplified liquid feeding program for calves. J. Dairy Sci. 65:1350. 15 Ragsdale, A. C. 1934. Growth standards for dairy cattle. Missouri Agric. Exp. Sin. Bull. 336 16 Ragsdale, A. C., and S. Brody. 1935. Estimating live weights in dairy cattle. Missouri Agric. Exp.
Journal of Dairy Science Vol. 70, No. 3, 1987
Stn. Bull. 354. 17 Sejrsen, K., J. T. Huber, H. A. Tucker, and R. M. Akers. 1982. Influence of nutrition on mammary development in pre- and postpubertal heifers. J. Dairy Sci. 65:793. 18 Swanson, E. W. 1960. Effect o f rapid growth with fattening of dairy heifers on their lactational ability. J. Dairy Sci. 43:377. 19 Swanson, E. W. 1967. Optimum growth patterns for dairy cattle. J. Dairy Sci. 50:244. 20 Swanson, E. W. 1971. Feed energy requirements for different rates of growth of dairy heifers. J. Dairy Sci. 54:217. 21 Wilk, J. C., C. W. Young, and C. L. Cole. 1963. Genetic and phenotypic relationships between certain body measurements and first lactation milk production in dairy cattle. J. Dairy Sci. 46:1273.