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Body Weights, Body Measurements, and Surface Area of Jersey and Sindhi-Jersey (F1) Crossbred Females
B O D Y W E I G H T S , B O D Y MEASURFgMENTS, AND S U R F A C E A R E A OF JERSEY AND SINDHI-JERSEY
(F~) C R O S S B R E D F E M A L E S
R. E. M c D O W E L L , DOUGLAS H. K. L E E , ~ It. W. M c M U L L A N , M. H. F O H R M A N , A~'D W. W. S W E T T
Dairy H~tsba~dry Research Bra~wh, Agric~dt~-ral l~esea.rch Sercice USDA, Beltsville, Md.
I n the cross-breeding investigations conducted as a p a r t of the Cooperative Southern Regional D a i r y Cattle Breeding Project, two groups of d a i r y cattle have been established at Beltsville, one of p u r e b r e d Jerseys, the other of F~ crosses of Red Sindhi (a Zebu breed) with Jerseys. F r o m the studies previously reported (6) it has been shown that the crossbred have a greater heat tolerance than the Jerseys. I n the process of endeavoring to determine the animal characteristics responsible for these observed differences, one of the first questions to arise was whether they nfight be due to body size or other morphological characters. I n any crossbreeding investigation, moreover, it is interesting to know how the crossbred p r o g e n y compare in size and body f o r m with the p a r e n t breeds and whether or not the crossbreds exhibit a n y evidence of heterosis or so-called "hybrid vigor." I n this p a p e r Sindhi-Jersey ( F , ) crosses are compared with their .Jersey dams in respect to weig'ht and with comparable Jerseys in respect to surface area and body form, as indicated by body measurements. METI{ODS
All crossbred animals in this s t u d y were raised in the same way as those in the p u r e b r e d herds at Beltsville, where the feeding and m a n a g e m e n t conform to good dairy practice. Whole milk is fed for the first 4 to 8 weeks, depending upon the vigor of the calf. A f t e r this, skinmfilk is fed up to 6 months of age. F r o m about 3 weeks of age, the calves are fed alfalfa h a y and a small amount of grain. The grain ration is gradually increased to a m a x i m u m of 3 lb. daily by the time that skimmilk feeding is diseontbmed. F o r heifers over 6 months of age and for d r y cows the ration consists of 4 lb. of grain, and hay ad libitum. D u r i n g lactation, hay, silage, and grain are fed in proportion to milk production and body weight. W i t h the exception of the first lactation, when the animals are barn-fed, pasture is used in season. Mean body weight, up to 12 months of age, is based on an average of weights taken on three consecutive days, at 30-day intervals. F r o m 12 months through 21 months, the means are based on single day weights. F o r lactating cows, the mean is based upon the average of monthly weights taken over the first 10 months of lactation, adjusted for age differences due to calving by reference to the growth s t a n d a r d for Beltsville Jerseys (4). :Received for publication J u n e 7, 1954. Professor of physiological climatology, Johns Hopkins University, Baltimore, ~Id. 1420
MEASUREMENTS
OF J E R N E ¥
AND
CROSSBRED
CATTLE
1421
F i f t e e n external measureinents, selected from 27 employed by the D a i r y H u s b a n d r y Research B r a n c h for studying the relationship between body f o r m and milk production (8), were used as indicators of body form. Values obtained on the crossbred animals are compared with the Beltsville herd average for Jerseys (unpublished d a t a ) . This is considered more desirable t h a n comparisons with standards which m a y be better known but which are derived f r o m animals maintained m~der different conditions. I n the first lactation group, direct d a u g h t e r - d a m comparisons were available and have been included as well. Body surface measurements were made with a surface integrator which consists of two wheels, the ciremnferences of which are known, mounted a fixed distance apart, and geared to a revolution couilter. One wheel has a roughened surface which rubs off chalk onto the hair coat as it is pushed over the surface. The surface area is measured on one side of the animal, with the auimaI standing squarely on all four feet, according' to a routine which has been described previously (5). RESULTS AND DISCUSSION
Bodg weight. F i g u r e 1 shows the comparative increase in body weight of Sindhi-Jersey (F~) crosses and their Jersey dams, f r o m b i r t h to 21 months of age, and the average of the first ten monthly weights during the first, second, and third lactations adjusted as described above. The values for heifers are based oil 45 pairs at birth, g r a d u a l l y decreasing to 31 pairs at 21 months of age. The lactation means are for 24, 18, and 11 pairs for the first, second, and t h i r d lactations, respectively. 2000
RetotionsNp
of
Body W e i g h t
Femoles
and
to A g e
their
Jersey
|n S}ndh~-Jersey (FI) Dams.
-o--
I000 900 80C 700 600
-4-
500 400
300
~c~ 200 o--- SindN- Jersey (F 1)
I00 90 80 70 60 0s 5
i L,lh I
i i i Z ~ 4
i S
' 6
' 7
AGE
' e
' i t ' ' ' ' I 9 to It iz 13 14 J5 i
(Months) ]~'IG. 1.
I I l I i 17 IS is 20
I
Lactations
1422
R. E. M(~DOWELL ET AL
On tile logarithmic scale, the slope of the line indicates the rate of growth independently of body size. The vertical distance between the two curves indicates the proportional difference in weights. [[he data indicate that the crossbred animals gain ~veight more readily than the Jerseys at the earlier ages alld maintain some of this gain even through the third lactation. The differences between the Jersey dams and the crosses are highly significant (1% level) f r o m birth through 15 months of age. F r o m 16 to 21 months of age, the differences are not signifieaut. The difference is highly significant (1% level) d u r i n g the first lactation but is not significant in the later lactations. These differences are even greater t h a n those reported by Rathore (7), who found that crossbred females exceeded pure Red Sindhis by 12% in body weight at 2 years of age. The average coefficient of variation in the weights for the crossbred heifers is substantially the same (8.1%) as that of the Jerseys (8.7%). W h e n the mean weights of the J e r s e y dams are compared with the Beltsville herd average for Jerseys (~), they tend to be slightly larger t h a n the herd average, but the differences are not significant. The size of the ~.rossbreds has been somewhat surprising, since p u r e b r e d Red Sindhis are smaller t h a n Jerseys. Joshi and Phillips (3) give the average weight of Red Sindhi calves at birth as 40 to 45 lb. for the females and 42 to 48 lb. for males; the average weight for females at 12 months of age as 330 to 3401b.; at 24 months, 515 to 525 lb. ; at 36 months, 640 to 650 lb. ; and at m a t u r i t y , 650 to 700 lb. These weights m a y be influenced to a certain degree by the adverse environment of India. F o u r Sindhi females born at Jeancrette, Louisiana, averTABLE
1
ComparativebodymeasurementsofJerseysandSindhi-Jerseycrossesat6~nonthsofage Jerseys ~ I t e m of m e a s u r e m e n t
H e r d av.
Standard error
(c,~.) Height at withers Height at hips L e n g t h of l e g ( f o r e l e g ) D e p t h of fo ro chest W i d t h of f o r e c h e s t W i d t h of h i p s W i d t h of p i n s B o d y l e n g t h ( w i t h e r s to h i p s ) L e n g t h of r u m p A n g l e of r u m p (o) T o t a l b o d y l e n g t h ( w i t h e r s to p i n s ) C i r c u m f e r e n c e of f o r e c h e s t C i r c u m f e r e n c e of p a u n c h L e n g t h of h e a d (poll to m o u t h ) W i d t h of h e a d ( w i d t h of eyes) a D a t a on 193 a n i m a l s a t B e l t s v i l l e . b D a t a on 36 crossbreds. ** S i g n i f i c a n t a t the 1 % level, * S i g n i f i c a n t a t the 5 % level.
95.4,q 97.75 51.04 44.44 23.35 27.36 16.71 58.46 29.08 --2.26 87.39 113.49 139.82 33.49 16.48
Crossbreds b Moan
Standard e rror
D i ffe re nc e s
0.472 0.417 0.467 0.213 0.250 0.169 0.225 0.439 0.248 0.607 0.474 t~.734 0.678 0.156 0,089
+2.72 ** +3.20 ** +1.72 ** +0.90 *~ +1.79 ** + 0.58 *~ +1.09 e~ --0.96 ~ --1.27 ~ +6.49 ~ --1.77 ~ + 4.84 ~ ÷2.17 ~ ÷2.91 ~ +0.32 ~
(cm.) 0.239 0.233 0.160 0.131 0.135 0.109 0.094 0.190 0.108 0.244 0.092 0.363 0.575 0.106 0.059
98.20 100.95 52.76 45.34 25.14 27.94 17.80 57.50 27.81 --8.75 85.62 118.33 141.99 36.40 16.80
(c~J~.)
MEASUREMENTS
OF JERSEY
AND
CROSSBRED
CATTLE
1423
aged 43 lb. at b i r t h , 202 lb. at 6 m o n t h s , 334 lb. a t 12 n m n t h s , a n d 408 lb. a t 18 m o n t h s of age. J o s h i a n d P h i l l i p s give the a v e r a g e w e i g h t of m a t u r e S i n d h i males as 950 to 1,000 lb. Of the t h r e e F , crossbred males used a t Beltsville, one weighed 1,678 lb. at 3 y e a r s a n d 6 n m n t h s , one w e i g h e d 1,488 lb. at 3 y e a r s a n d i m o n t h , a n d the t h i r d weighed 1,408 lb. at 2 y e a r s a n d 1 m o u t h of age. These weights i n d i c a t e as g r e a t or g r e a t e r increase i n weight i n the F~ males as was s h o w n i n the females. The l a r g e r size of the female crosses d u r i n g the t h r e e l a c t a t i o n p e r i o d s is associated i n p a r t w i t h the fact t h a t t h e y u s u a l l y showed a s m a l l e r decrease i n b o d y weight a f t e r c a l v i n g a n d recovered more q u i c k l y to t h e i r n o r m a l weight. B o d y m e a s u r e m e ~ t s . Tables 1, 2, 3, a n d 4 give the c o m p a r a t i v e b o d y m e a s u r e m e n t s of J e r s e y s a n d S i n d h i - J e r s e y (F~) crosses at 6, 12, a n d 18 m o n t h s of age a n d at first l a c t a t i o n , respectively. T a b l e I shows t h a t the crossbreds are t a l l e r a n d have g r e a t e r b o d y w i d t h a n d d e p t h b u t t h a t the l e n g t h of b o d y ( w i t h e r s to h i p s ) a n d l e n g t h of r u m p arc s h o r t e r t h a n those of the Jerseys. The most sign i f i c a n t differences at 6 m o n t h s of age are in the a n g l e of r u m p a n d l e n g t h of head. F r o m Tables 2, 3, a n d 4 it will be seen t h a t i n most cases the differences b e t w e e n the two g r o u p s d i m i n i s h w i t h age to a n o n s i g n i f i c a n t v a l u e or a c t u a l l y become reversed. The a n g l e of r u m p a n d l e n g t h of head, however, are g r e a t e r i n the crosses at all ages. T a b l e 4 also i n c l u d e s the m e a n s a n d s t a n d a r d errors for the J e r s e y dams. I t will be seen t h a t the m e a n s for the J e r s e y dams are v e r y s i m i l a r to those of the h e r d average. The a v e r a g e coefficient of v a r i a t i o n of the d a m s a n d crossbred TABLE 2 Comparative body meas~tre,ments of Jerseys and Sindhi-Jersey crosses at 12 ~onths of age Jerseys ~ Item of measurement I-Ieight at ~-ithers Height at hips Length of leg (foreleg) Depth of forechest Width of 2orechest Width of hips Width of pins Body length (withers to hips) Length of rmnp Angle of rump ,o) Total body length (withers t~ pins) Circumference of forechest Circumference of paunch Length of head (poll to mouth) Width of head (width of eyes)
Crossbreds b
Herd av.
Standard error
Mean
(cm.) 110.03 II 1.94 54.90 55.13 30.76 36.30 22.50 70.38 35.57 --2.85 105.95 142.15 171.32 39.88 19.13
0.201 0.195 0.151 0.1] 5 0.157 0.106 0.122 0.206 0.103 0.257 0.242 0.365 0.644 0.108 0.058
(eTch.) 110,81 112.93 56.12 54.73 31.66 35.81 22.32 68.03 33.42 --9.72 101.45 144.] 6 171.47 42.76 ] 8.93
Data on 198 animals in the Beltsville herd. Data on 32 erossbreds. ~ Significant at the 1% level. Significant at the 5% level.
Standard error Differences 0.501 0.463 0.381 0,213 0.242 0.218 0.192 0.534 0.248 0.585 0.584 0.502 1.036 0.197 0.127
(cm.) +0.78 +0,99 + +1,22 ++ --0.40 +0.90 ++ --0.49~ --0.18 --2.35 ~ --2.15 ~ +6.87 ~ --4.50 ~ +2.01 ~ +0.15 +2.88 a~ --0.20
1424
~. E. McDO\VELL E'I' AL
TABLE 3 Co~nparatlve body meas~lrcmcnts of Jerseys and Sindhi-Jcrsey crosses at 18 ,months of age Jerseys" I t e m of m e a s u r e m e n t
Herd nv.
Standard error
5[ean
0.196 0.198 0.153 0.133 0.168 0.128 0.122 0.230 0.101 0.254 0.269 0.437 0.665 0.118 I).05~
11.7.48 118.55 58.00 59.43 35.05 40.15 25.29 73.51 36.30 --10.17 109.64 156.22 178.75 45.78 20.05
(c,~.) t t e i g h t at withers t i e i g h t at hips L e n g t h of leg (foreleg) D e p t h of forechest W i d t h of forechest W i d t h of hips W i d t h of pins Body length ( w i t h e r s to hips) L e n g t h of runlp Angle of r u m p to~ Total body length (withers to pins) Circumference of forechest Circumference of pannch L e n g t h of head (poll to m o n t h ) W i d t h of head (width of eyes)
117.18 118.~3 56.30 60.85 34.35 41.23 25.99 76.74 38.91 --4.20 115.64 157.01 ] 83.92 43.13 20.48
Crossbreds ~' Standard error
Differences
0.493 0.575 0.3.37 0.266 0.333 0.254 0.286 0.586 0.297 0.775 0.641 0.713 1.668 0.269 0.166
+0.30 --0.28 +1.70 *~ --1.42 ~ +0.70 ~ --1.08 ~ --0.70 ~ --.%23 ~* --2.61 ~ +5.97 ~ --6.00 ~ --0.79 --5.18 ~ +2.65 --0.43 ~
(cm.)
(c,~.)
D a t a on 191 animals in the Beltsville her,]. b D a t a on 30 crossbreds. ~ Significant at the 1 ~ level. Significant at the 5% level.
daughters was substantially the same for the two groups (6.06 and 6.12%, respectively). This indicates that the crosses were as m f i f o r m with respect to body f o r m as their dams at the time of measurement. The available data on body mcasurenmnts of p u r e Red Sindhis are very limited. Table 5 presents the average measurements for f o u r body dimensions for Sindhis in I n d i a as given b y Joshi and Phillips (3). The data show t h a t Sindhis in I n d i a are definitely smaller in all respects than the Jerseys at Beltsville. The s u m m a r y comparison, based on the t test of significance, for the difference between the Jersey herd average and the F, crosses, for all ages, is given in Table 6. Fronl this table it can readily be observed that the advantage in height of the crosses at 6 months diminishes to a non.~ignifieaut value at later ages. The crosses also show greater depth, width, body circumference, and width of head at 6 months of age. These values become nonsignificant or significant in favor of the J e r s e y during first lactation. The Jerseys a p p e a r to have a greater body length at all ages. The differences between the two groups for angle of r u m p and length of head are significantly greater (]')~ level) for the crosses at all ages. Surface area. I n a previous publication (5), p r e l i m i n a r y measurements of surface area made on 20 J e r s e y and 20 Sindhi-Jersey crossbred animals were published. Since that time, more animals have been measured, but no substantial change occurred in the results. The data obtained on the larger group are given in Table 7. F r o m this it will be seen that there is no significant difference between the J e r s e y s and the erossbreds in relative surface area. I t would seem that any
~EASUREMENTS OF JERSEY AND CROSSBRED CATTLE
1425
TABLE 4
Comparative body measurements of Jersey and Sindhi-Jersey crosses m a d e 3 m o n t h s a f t e r c a l v i n g d~lring firstlactation Jersey dams I t e m of m e a s u r e m e n t
Mean"
Jerseys
Std. error
Herd av. b
0.629 0.591 0.433 0.398 0.425 0.274 0.249 0.433 0.211 0.501 0.527 0.811 1.339 0.248 0.176
123.29 123.45 57.38 65.91 38.27 47.67 29.01 82.73 42.89 --4.32 125.74 171.01 207.28 46,01 21.41
(c,~.) Height at withers Height at hips L e n g t h of leg ( f o r e l e g ) D e p t h of f o r e c h e s t W i d t h of f o r e c h e s t W i d t h of h i p s W i d t h of p i n s B o d y l e n g t h ( w i t h e r s to h i p s ) L e n g t h of r u m p A n g l e of r u m p (o~ T o t a l b o d y l e n g t h ( w i t h e r s to p i n s ) C i r c u m f e r e n c e of f o r e c h e s t C i r c u m f e r e n c e of p a u n c h L e n g t h of h e a d ( p o l l t o m o u t h ) W i d t h of h e a d ( w i d t h of eyes)
C ros s bre ds
Std. e rror
Std. Mean ¢
(era.)
122.17 123.00 57.47 64.79 36.24 46.78 28.49 82.27 42.68 --4.78 124.91 167.76 202.35
45.55 21.54
error
(era.) 0.200 0.205 0.190 0.164 0.199 0.169 0.148 0,214 0.137 0.240 0,095 0.528 0.751 0.117 0.060
122.36 123.42 58.02 64.34 37.69 45.55 27.39 79.57 39,17 --10.30 118.74 168.95 201.68 48.75 20.00
Differenees d
(cm.) 0.573 0.658 0.446 0,266 0.401 0.315 0.267 0.747 0.245 0.823 0.944 0.7~5 0.890 0.28,q 0.496
--0.93 --0.03 + 0.64 --1.57 ~ --0.58 --2.12 ~ --1.62 ~~ --3.16 ~ --3.72 ~ +5.98 ~'~ --7.00 a~--2.06 ~ --5.60 ~ +2.74 ~ --1.41 ~
M e a n f o r 22 J e r s e y d a m s ; a v e r a g e a g e 2 yr., 4 me. D a t a on 193 a n i m a l s in the B c l t s v i l l e herd, a v e r a g e a ge 2 yr., 4 hie. M e a n for 22 F~ c r o s s b r e d s ; a v e r a g e a g e 2 yr., 4 me. a Differen ce b e t w e e n c r o s s b r e d m e a n a n d J e r s e y h e r d a v e r a g e . ~ S i g n i f i c a n t a t the 1 % level. S i g n i f i c a n t a t the 5 % level.
increase in surface area that the erossbreds may gain from dewlap developnlent is offset by other contour changes, such as tile roundness of the hips, which result in corresponding decreases. F r o m these figures it also will be seen that the correlation between surface area and body weight is not significantly inlproved if the comparison is nlade to the two-thirds power of body weight instead of to weight directly. As was previously pointed out (5), the measurements reported by B r o d y and Elting (1) are similarly unaffected by substituting the two-thirds power for the direct body weight, as long as adult animals are being considered. On the other hand, when tile data of HogmL and Skouby (2), quoted by E]ting and Brody, are examined, it appears that a better correlation is obtained even in their adult animals when a power of body weight is used. This led the authors TABLE 5
Average measurements of fo~r body d imensioJ~s of Red Sindhi cattle in India as reported by Joshi a~d Phillips (3) Age 1 year I t e m of m e a s u r e n m n t
No.
Mean
2 years No.
(cm.) Height at withers D e p t h of f o r e e h e s t W i d t h of h i p s C i r c u m f e r e n c e of f o r e c h e s t
12 12 12 12
96.62 47.63 28.78 ] l 7.48
Mean
Mature No.
Mean
51 51 51 51
120.73 62.51 42.09 158.37
(c,~.) 12 12 ]2 12
106.02 60.96 33.43 133.99
(c,~.)
R. E. McDOWELL ET AL
2126
TABLE 6
S~mmary comparison of body measurements of Jerseys (herd average) and Sindhi-Jersey crosses at various ages I t e m of m e a s u r e m e n t
6 months
12 m o n t h s
18 m o n t h s
1st lactation
+ + + + + + + + + + + + + + .
0 + + + 0 q-+ . 0
0 0 + +
0 0 0 --0
H e i g h t at withers t I e i g h t at hips L e n g t h of leg (foreleg) Depth of forechest W i d t h of foreehest W i d t h of hil)s Width of pins Body length (withers to hips ) L e n g t h of rump Angle of r u m p (o) Total body length (withers to pins) Circumference of forechest C i r c u m f e r e u c e of p a u n c h
L e n g t h of head (poll to m o u t h ) W i d t h of head (width of eyes.)
.
.
.
. .
.
.
++
.
q. -.
.
++ . . + +
-{-+ + + ++ + +
.
.
. --. .
.
W-t. . 0
0
++ . --- - -
++ 0
++ --
++ ----
+ + Crosses significantly l a r g e r (1% level) t h a n J e r s e y . + Crosses significantly l a r g e r (5% level) t h a n Jersey. 0 Difference not significant. -- Crosses significantly smaller ( 5 % level) t h a n Jersey. ---- Crosses significantly smaller ( 1 % level) t h a n Jersey.
to subject their own as well as H o g a n and Skouby's data to a multiple regression analysis to determine what powers of body weight and total length fit the data best in the expression : A = K W~L b or L o g A = l o g K + a log W + b log L Where A is surface area, W is body weight, L is total body length (withers to pin-bones), K is a constant depending upon the units used, and a and b are power constants. The results of these analyses are given in Table 8. I t will be seen that the present authors' results differ considerably from those reported by H o g a n and Skouby. I t is believed that these differences cannot be attributed to differences in the teehlfique used for measuring surface area but nlust reflect real differences between the two groups of animals. I n adult Jerseys TABLE 7
Comparisons of surface areas and body weights and the relationships betu'ee~ surface area and body weight for 32 Jerseys and 23 Sindhi-Jersey (Fj) crossbred mat~tre cows Jersey Item Surface area (sq. m.) Body w e i g h t (kg.) S.A. (sq. c m . ) / B . W . ~ Correlation between S.A. and B.W. :Regression S.A. on ]~.W. S.A. (sq. c m . ) / ( B . W . ) °'°7 Correlation between S.A. and (B.W.) °'~: S u r f a c e a r e a / b o d y weight.
Value 4.26 454.97 94.44 0.715 0.0045 724.57 0.739
Sindhi-Jersey
Standard error 0.042 6.57 0.88 0.167 0.0008 4.43 0.161
Value 4.13 441.43 93.60 0.730 0.0050 712.03 0.749
Standard error 0.067 9.84 1.462 0.211 0.0011 8.15 0.206
.MEARUB~EMENTR
OF
,JEffREY
AND
('ROSSBI~ED
1427
CATTLE
TABLE 8 Powers of hotly weight al~d te~gth giving best fit in prediction for.m~das for s~trface area Using weight and length
Authors
Method of measuring surface area
}feDowell et al.
Surface integrator
Adult Jerseys
0.4795
0.0496
1790
"2277
iMcDowell et al.
Surface integrator
Adult SindhiJerseys
0.4821
-0.0916
3392
2189
I-Iogan and Skouby
Paper mould
Beef breeds of similar weight
0.2109
0.6651
504
I-Iogan and Skouby
Paper mould
All adult beef aninmls
0.3136
0.6523
286
Nature of cattle
Weight power (a)
Length power (b)
Constant (K)
Constant if length discarded (K')
and Sindhi-Jerseys the authors find total body length to have no significant relationship with surface area, whereas in the beef animals Hogan and Skouby found it to be more marked than the association of body weight with surface area. This nmy reflect basic differences between beef and dairy breeds, but it may be that the genetic u n i f o r m i t y of the dairy cattle studied by the authors minimizes the possible influence of body length and throws correspondingly into relief the influence of body weight. I f this supposition is true, then within a morphologically uniform breed a good estimate of the surface area could be obtained from the weight alone, preferably using the square root of the body weight as the basis of calculation. Before this is accepted, however, f u r t h e r studies should be carried out within uniform groups of beef animals and among more widely v a r y i n g breeds of d a i r y cattle. SUMMARY
Data are presented on comparative body weights, body dimensions, and "the measured surface area of Jerseys and Sindhi-Jerse~: (F1) crosses. The mean body weights of the erossbreds are greater than those of the Jersey dams at comparable ages and stages of lactation. This difference, which may be attributable to " h y b r i d vigor", in the crossbreds, is most evident from birth to 15 months of age. Body measurements made at 6, ]2, and 18 months of age and during first lactation show that at the earlier ages the crossbreds are taller and have greater body width and depth, but that their body length is less. With the advance o f age, the differences for most measurements, other than weight, between the two groups diminish to a nonsignificant value or actually become reversed. The crosses exceed the Jerseys, however, in angle of r u m p and length of head at all ages. The average coefficients of variation for body weight and body dimensions arc substantially the same for both groups.
1428
R. E. MeDOV,~ELL ET AL
T h e s u r f a c e a r e a w a s m e a s u r e d on 32 J e r s e y a n d 23 S i n d h i - J e r s e y c r o s s b r e d cows w i t h a s u r f a c e i n t e g r a t o r . T h e s e a r e a s w e r e c o m p a r e d w i t h b o d y w e i g h t s . N e i t h e r t h e r a t i o of s u r f a c e a r e a to b o d y w e i g h t n o r t h e r a t i o of s u r f a c e a r e a to t h e t w o - t h i r d s p o w e r of b o d y w e i g h t s h o w s a s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e two groups. ]n these animals a statistical analysis indicated that the surface a r e a is r e l a t e d to t h e s q u a r e r o o t of b o d y w e i g h t b u t to n o a p p r e c i a b l e e x t e n t to total body length. REFERENUES (1) BRODY, S., AND ELTIN(~, E. C. A Formula for Estimating Surface Area of Dairy Cattle. J. Agr. Research, 33: 3. 1926. (2') HOG.~, A. G., AND SKO,'BY, D. I. Determination of the Surface Area of Cattle and Swine. J. Agr. Researcl~, 25: 10. 1923. (3) Jos~tI, N. 1~., .~.~D PHILLIPS, 1~. W. Zebu Cattle of India and Pakistan. FAO Agrictdtural St~ldy No. 19, Rome, Italy. 1953. (4) M~TTHEWS, C. A. Standards for Normal Growth in Weights for Jersey Cattle. USDA TccL B~dI. (in press). (5) McDOWELL, R. E., L~E, D. H. K., _~'D FOHR~[_~N, M. It. The Relationship of Surface Area to Heat Tolerance in Jerseys and Sindhi-Jersey (F~) Crossbred Cows. J. Animal Sci., 12: 4. 1953. (6/ ~[CDO~VELL, R. E., LEE, D. H. K., FOHRMA~', M. H., SYKES, J. F., AND ANDERSON, R. A. Rectal Temperature and Responses of Jersey and Sindhi-Jersey F~ Crossbred Cows to a Standard Hot Atmosphere. J. Dairy Sci. (Submitted). (7) R.XTHORF,A. Differences in Growth of Red Sindhi and Crosses of Red Sindhi with Jersey, Brown Swiss, Holstein-Friesian, and Guernsey Cattle. Ph.D. thesis, low~ State College, Ames. 1949. /8) S~VETT, W. W., AND GRAVES, ~. R. Relation between Conformation and Anatomy of Cows of Unknown Producing Ability. J . . l g r . Besearel~, 58: 199. 1939.
(F~) C R O S S B R E D F E M A L E S
R. E. M c D O W E L L , DOUGLAS H. K. L E E , ~ It. W. M c M U L L A N , M. H. F O H R M A N , A~'D W. W. S W E T T
Dairy H~tsba~dry Research Bra~wh, Agric~dt~-ral l~esea.rch Sercice USDA, Beltsville, Md.
I n the cross-breeding investigations conducted as a p a r t of the Cooperative Southern Regional D a i r y Cattle Breeding Project, two groups of d a i r y cattle have been established at Beltsville, one of p u r e b r e d Jerseys, the other of F~ crosses of Red Sindhi (a Zebu breed) with Jerseys. F r o m the studies previously reported (6) it has been shown that the crossbred have a greater heat tolerance than the Jerseys. I n the process of endeavoring to determine the animal characteristics responsible for these observed differences, one of the first questions to arise was whether they nfight be due to body size or other morphological characters. I n any crossbreeding investigation, moreover, it is interesting to know how the crossbred p r o g e n y compare in size and body f o r m with the p a r e n t breeds and whether or not the crossbreds exhibit a n y evidence of heterosis or so-called "hybrid vigor." I n this p a p e r Sindhi-Jersey ( F , ) crosses are compared with their .Jersey dams in respect to weig'ht and with comparable Jerseys in respect to surface area and body form, as indicated by body measurements. METI{ODS
All crossbred animals in this s t u d y were raised in the same way as those in the p u r e b r e d herds at Beltsville, where the feeding and m a n a g e m e n t conform to good dairy practice. Whole milk is fed for the first 4 to 8 weeks, depending upon the vigor of the calf. A f t e r this, skinmfilk is fed up to 6 months of age. F r o m about 3 weeks of age, the calves are fed alfalfa h a y and a small amount of grain. The grain ration is gradually increased to a m a x i m u m of 3 lb. daily by the time that skimmilk feeding is diseontbmed. F o r heifers over 6 months of age and for d r y cows the ration consists of 4 lb. of grain, and hay ad libitum. D u r i n g lactation, hay, silage, and grain are fed in proportion to milk production and body weight. W i t h the exception of the first lactation, when the animals are barn-fed, pasture is used in season. Mean body weight, up to 12 months of age, is based on an average of weights taken on three consecutive days, at 30-day intervals. F r o m 12 months through 21 months, the means are based on single day weights. F o r lactating cows, the mean is based upon the average of monthly weights taken over the first 10 months of lactation, adjusted for age differences due to calving by reference to the growth s t a n d a r d for Beltsville Jerseys (4). :Received for publication J u n e 7, 1954. Professor of physiological climatology, Johns Hopkins University, Baltimore, ~Id. 1420
MEASUREMENTS
OF J E R N E ¥
AND
CROSSBRED
CATTLE
1421
F i f t e e n external measureinents, selected from 27 employed by the D a i r y H u s b a n d r y Research B r a n c h for studying the relationship between body f o r m and milk production (8), were used as indicators of body form. Values obtained on the crossbred animals are compared with the Beltsville herd average for Jerseys (unpublished d a t a ) . This is considered more desirable t h a n comparisons with standards which m a y be better known but which are derived f r o m animals maintained m~der different conditions. I n the first lactation group, direct d a u g h t e r - d a m comparisons were available and have been included as well. Body surface measurements were made with a surface integrator which consists of two wheels, the ciremnferences of which are known, mounted a fixed distance apart, and geared to a revolution couilter. One wheel has a roughened surface which rubs off chalk onto the hair coat as it is pushed over the surface. The surface area is measured on one side of the animal, with the auimaI standing squarely on all four feet, according' to a routine which has been described previously (5). RESULTS AND DISCUSSION
Bodg weight. F i g u r e 1 shows the comparative increase in body weight of Sindhi-Jersey (F~) crosses and their Jersey dams, f r o m b i r t h to 21 months of age, and the average of the first ten monthly weights during the first, second, and third lactations adjusted as described above. The values for heifers are based oil 45 pairs at birth, g r a d u a l l y decreasing to 31 pairs at 21 months of age. The lactation means are for 24, 18, and 11 pairs for the first, second, and t h i r d lactations, respectively. 2000
RetotionsNp
of
Body W e i g h t
Femoles
and
to A g e
their
Jersey
|n S}ndh~-Jersey (FI) Dams.
-o--
I000 900 80C 700 600
-4-
500 400
300
~c~ 200 o--- SindN- Jersey (F 1)
I00 90 80 70 60 0s 5
i L,lh I
i i i Z ~ 4
i S
' 6
' 7
AGE
' e
' i t ' ' ' ' I 9 to It iz 13 14 J5 i
(Months) ]~'IG. 1.
I I l I i 17 IS is 20
I
Lactations
1422
R. E. M(~DOWELL ET AL
On tile logarithmic scale, the slope of the line indicates the rate of growth independently of body size. The vertical distance between the two curves indicates the proportional difference in weights. [[he data indicate that the crossbred animals gain ~veight more readily than the Jerseys at the earlier ages alld maintain some of this gain even through the third lactation. The differences between the Jersey dams and the crosses are highly significant (1% level) f r o m birth through 15 months of age. F r o m 16 to 21 months of age, the differences are not signifieaut. The difference is highly significant (1% level) d u r i n g the first lactation but is not significant in the later lactations. These differences are even greater t h a n those reported by Rathore (7), who found that crossbred females exceeded pure Red Sindhis by 12% in body weight at 2 years of age. The average coefficient of variation in the weights for the crossbred heifers is substantially the same (8.1%) as that of the Jerseys (8.7%). W h e n the mean weights of the J e r s e y dams are compared with the Beltsville herd average for Jerseys (~), they tend to be slightly larger t h a n the herd average, but the differences are not significant. The size of the ~.rossbreds has been somewhat surprising, since p u r e b r e d Red Sindhis are smaller t h a n Jerseys. Joshi and Phillips (3) give the average weight of Red Sindhi calves at birth as 40 to 45 lb. for the females and 42 to 48 lb. for males; the average weight for females at 12 months of age as 330 to 3401b.; at 24 months, 515 to 525 lb. ; at 36 months, 640 to 650 lb. ; and at m a t u r i t y , 650 to 700 lb. These weights m a y be influenced to a certain degree by the adverse environment of India. F o u r Sindhi females born at Jeancrette, Louisiana, averTABLE
1
ComparativebodymeasurementsofJerseysandSindhi-Jerseycrossesat6~nonthsofage Jerseys ~ I t e m of m e a s u r e m e n t
H e r d av.
Standard error
(c,~.) Height at withers Height at hips L e n g t h of l e g ( f o r e l e g ) D e p t h of fo ro chest W i d t h of f o r e c h e s t W i d t h of h i p s W i d t h of p i n s B o d y l e n g t h ( w i t h e r s to h i p s ) L e n g t h of r u m p A n g l e of r u m p (o) T o t a l b o d y l e n g t h ( w i t h e r s to p i n s ) C i r c u m f e r e n c e of f o r e c h e s t C i r c u m f e r e n c e of p a u n c h L e n g t h of h e a d (poll to m o u t h ) W i d t h of h e a d ( w i d t h of eyes) a D a t a on 193 a n i m a l s a t B e l t s v i l l e . b D a t a on 36 crossbreds. ** S i g n i f i c a n t a t the 1 % level, * S i g n i f i c a n t a t the 5 % level.
95.4,q 97.75 51.04 44.44 23.35 27.36 16.71 58.46 29.08 --2.26 87.39 113.49 139.82 33.49 16.48
Crossbreds b Moan
Standard e rror
D i ffe re nc e s
0.472 0.417 0.467 0.213 0.250 0.169 0.225 0.439 0.248 0.607 0.474 t~.734 0.678 0.156 0,089
+2.72 ** +3.20 ** +1.72 ** +0.90 *~ +1.79 ** + 0.58 *~ +1.09 e~ --0.96 ~ --1.27 ~ +6.49 ~ --1.77 ~ + 4.84 ~ ÷2.17 ~ ÷2.91 ~ +0.32 ~
(cm.) 0.239 0.233 0.160 0.131 0.135 0.109 0.094 0.190 0.108 0.244 0.092 0.363 0.575 0.106 0.059
98.20 100.95 52.76 45.34 25.14 27.94 17.80 57.50 27.81 --8.75 85.62 118.33 141.99 36.40 16.80
(c~J~.)
MEASUREMENTS
OF JERSEY
AND
CROSSBRED
CATTLE
1423
aged 43 lb. at b i r t h , 202 lb. at 6 m o n t h s , 334 lb. a t 12 n m n t h s , a n d 408 lb. a t 18 m o n t h s of age. J o s h i a n d P h i l l i p s give the a v e r a g e w e i g h t of m a t u r e S i n d h i males as 950 to 1,000 lb. Of the t h r e e F , crossbred males used a t Beltsville, one weighed 1,678 lb. at 3 y e a r s a n d 6 n m n t h s , one w e i g h e d 1,488 lb. at 3 y e a r s a n d i m o n t h , a n d the t h i r d weighed 1,408 lb. at 2 y e a r s a n d 1 m o u t h of age. These weights i n d i c a t e as g r e a t or g r e a t e r increase i n weight i n the F~ males as was s h o w n i n the females. The l a r g e r size of the female crosses d u r i n g the t h r e e l a c t a t i o n p e r i o d s is associated i n p a r t w i t h the fact t h a t t h e y u s u a l l y showed a s m a l l e r decrease i n b o d y weight a f t e r c a l v i n g a n d recovered more q u i c k l y to t h e i r n o r m a l weight. B o d y m e a s u r e m e ~ t s . Tables 1, 2, 3, a n d 4 give the c o m p a r a t i v e b o d y m e a s u r e m e n t s of J e r s e y s a n d S i n d h i - J e r s e y (F~) crosses at 6, 12, a n d 18 m o n t h s of age a n d at first l a c t a t i o n , respectively. T a b l e I shows t h a t the crossbreds are t a l l e r a n d have g r e a t e r b o d y w i d t h a n d d e p t h b u t t h a t the l e n g t h of b o d y ( w i t h e r s to h i p s ) a n d l e n g t h of r u m p arc s h o r t e r t h a n those of the Jerseys. The most sign i f i c a n t differences at 6 m o n t h s of age are in the a n g l e of r u m p a n d l e n g t h of head. F r o m Tables 2, 3, a n d 4 it will be seen t h a t i n most cases the differences b e t w e e n the two g r o u p s d i m i n i s h w i t h age to a n o n s i g n i f i c a n t v a l u e or a c t u a l l y become reversed. The a n g l e of r u m p a n d l e n g t h of head, however, are g r e a t e r i n the crosses at all ages. T a b l e 4 also i n c l u d e s the m e a n s a n d s t a n d a r d errors for the J e r s e y dams. I t will be seen t h a t the m e a n s for the J e r s e y dams are v e r y s i m i l a r to those of the h e r d average. The a v e r a g e coefficient of v a r i a t i o n of the d a m s a n d crossbred TABLE 2 Comparative body meas~tre,ments of Jerseys and Sindhi-Jersey crosses at 12 ~onths of age Jerseys ~ Item of measurement I-Ieight at ~-ithers Height at hips Length of leg (foreleg) Depth of forechest Width of 2orechest Width of hips Width of pins Body length (withers to hips) Length of rmnp Angle of rump ,o) Total body length (withers t~ pins) Circumference of forechest Circumference of paunch Length of head (poll to mouth) Width of head (width of eyes)
Crossbreds b
Herd av.
Standard error
Mean
(cm.) 110.03 II 1.94 54.90 55.13 30.76 36.30 22.50 70.38 35.57 --2.85 105.95 142.15 171.32 39.88 19.13
0.201 0.195 0.151 0.1] 5 0.157 0.106 0.122 0.206 0.103 0.257 0.242 0.365 0.644 0.108 0.058
(eTch.) 110,81 112.93 56.12 54.73 31.66 35.81 22.32 68.03 33.42 --9.72 101.45 144.] 6 171.47 42.76 ] 8.93
Data on 198 animals in the Beltsville herd. Data on 32 erossbreds. ~ Significant at the 1% level. Significant at the 5% level.
Standard error Differences 0.501 0.463 0.381 0,213 0.242 0.218 0.192 0.534 0.248 0.585 0.584 0.502 1.036 0.197 0.127
(cm.) +0.78 +0,99 + +1,22 ++ --0.40 +0.90 ++ --0.49~ --0.18 --2.35 ~ --2.15 ~ +6.87 ~ --4.50 ~ +2.01 ~ +0.15 +2.88 a~ --0.20
1424
~. E. McDO\VELL E'I' AL
TABLE 3 Co~nparatlve body meas~lrcmcnts of Jerseys and Sindhi-Jcrsey crosses at 18 ,months of age Jerseys" I t e m of m e a s u r e m e n t
Herd nv.
Standard error
5[ean
0.196 0.198 0.153 0.133 0.168 0.128 0.122 0.230 0.101 0.254 0.269 0.437 0.665 0.118 I).05~
11.7.48 118.55 58.00 59.43 35.05 40.15 25.29 73.51 36.30 --10.17 109.64 156.22 178.75 45.78 20.05
(c,~.) t t e i g h t at withers t i e i g h t at hips L e n g t h of leg (foreleg) D e p t h of forechest W i d t h of forechest W i d t h of hips W i d t h of pins Body length ( w i t h e r s to hips) L e n g t h of runlp Angle of r u m p to~ Total body length (withers to pins) Circumference of forechest Circumference of pannch L e n g t h of head (poll to m o n t h ) W i d t h of head (width of eyes)
117.18 118.~3 56.30 60.85 34.35 41.23 25.99 76.74 38.91 --4.20 115.64 157.01 ] 83.92 43.13 20.48
Crossbreds ~' Standard error
Differences
0.493 0.575 0.3.37 0.266 0.333 0.254 0.286 0.586 0.297 0.775 0.641 0.713 1.668 0.269 0.166
+0.30 --0.28 +1.70 *~ --1.42 ~ +0.70 ~ --1.08 ~ --0.70 ~ --.%23 ~* --2.61 ~ +5.97 ~ --6.00 ~ --0.79 --5.18 ~ +2.65 --0.43 ~
(cm.)
(c,~.)
D a t a on 191 animals in the Beltsville her,]. b D a t a on 30 crossbreds. ~ Significant at the 1 ~ level. Significant at the 5% level.
daughters was substantially the same for the two groups (6.06 and 6.12%, respectively). This indicates that the crosses were as m f i f o r m with respect to body f o r m as their dams at the time of measurement. The available data on body mcasurenmnts of p u r e Red Sindhis are very limited. Table 5 presents the average measurements for f o u r body dimensions for Sindhis in I n d i a as given b y Joshi and Phillips (3). The data show t h a t Sindhis in I n d i a are definitely smaller in all respects than the Jerseys at Beltsville. The s u m m a r y comparison, based on the t test of significance, for the difference between the Jersey herd average and the F, crosses, for all ages, is given in Table 6. Fronl this table it can readily be observed that the advantage in height of the crosses at 6 months diminishes to a non.~ignifieaut value at later ages. The crosses also show greater depth, width, body circumference, and width of head at 6 months of age. These values become nonsignificant or significant in favor of the J e r s e y during first lactation. The Jerseys a p p e a r to have a greater body length at all ages. The differences between the two groups for angle of r u m p and length of head are significantly greater (]')~ level) for the crosses at all ages. Surface area. I n a previous publication (5), p r e l i m i n a r y measurements of surface area made on 20 J e r s e y and 20 Sindhi-Jersey crossbred animals were published. Since that time, more animals have been measured, but no substantial change occurred in the results. The data obtained on the larger group are given in Table 7. F r o m this it will be seen that there is no significant difference between the J e r s e y s and the erossbreds in relative surface area. I t would seem that any
~EASUREMENTS OF JERSEY AND CROSSBRED CATTLE
1425
TABLE 4
Comparative body measurements of Jersey and Sindhi-Jersey crosses m a d e 3 m o n t h s a f t e r c a l v i n g d~lring firstlactation Jersey dams I t e m of m e a s u r e m e n t
Mean"
Jerseys
Std. error
Herd av. b
0.629 0.591 0.433 0.398 0.425 0.274 0.249 0.433 0.211 0.501 0.527 0.811 1.339 0.248 0.176
123.29 123.45 57.38 65.91 38.27 47.67 29.01 82.73 42.89 --4.32 125.74 171.01 207.28 46,01 21.41
(c,~.) Height at withers Height at hips L e n g t h of leg ( f o r e l e g ) D e p t h of f o r e c h e s t W i d t h of f o r e c h e s t W i d t h of h i p s W i d t h of p i n s B o d y l e n g t h ( w i t h e r s to h i p s ) L e n g t h of r u m p A n g l e of r u m p (o~ T o t a l b o d y l e n g t h ( w i t h e r s to p i n s ) C i r c u m f e r e n c e of f o r e c h e s t C i r c u m f e r e n c e of p a u n c h L e n g t h of h e a d ( p o l l t o m o u t h ) W i d t h of h e a d ( w i d t h of eyes)
C ros s bre ds
Std. e rror
Std. Mean ¢
(era.)
122.17 123.00 57.47 64.79 36.24 46.78 28.49 82.27 42.68 --4.78 124.91 167.76 202.35
45.55 21.54
error
(era.) 0.200 0.205 0.190 0.164 0.199 0.169 0.148 0,214 0.137 0.240 0,095 0.528 0.751 0.117 0.060
122.36 123.42 58.02 64.34 37.69 45.55 27.39 79.57 39,17 --10.30 118.74 168.95 201.68 48.75 20.00
Differenees d
(cm.) 0.573 0.658 0.446 0,266 0.401 0.315 0.267 0.747 0.245 0.823 0.944 0.7~5 0.890 0.28,q 0.496
--0.93 --0.03 + 0.64 --1.57 ~ --0.58 --2.12 ~ --1.62 ~~ --3.16 ~ --3.72 ~ +5.98 ~'~ --7.00 a~--2.06 ~ --5.60 ~ +2.74 ~ --1.41 ~
M e a n f o r 22 J e r s e y d a m s ; a v e r a g e a g e 2 yr., 4 me. D a t a on 193 a n i m a l s in the B c l t s v i l l e herd, a v e r a g e a ge 2 yr., 4 hie. M e a n for 22 F~ c r o s s b r e d s ; a v e r a g e a g e 2 yr., 4 me. a Differen ce b e t w e e n c r o s s b r e d m e a n a n d J e r s e y h e r d a v e r a g e . ~ S i g n i f i c a n t a t the 1 % level. S i g n i f i c a n t a t the 5 % level.
increase in surface area that the erossbreds may gain from dewlap developnlent is offset by other contour changes, such as tile roundness of the hips, which result in corresponding decreases. F r o m these figures it also will be seen that the correlation between surface area and body weight is not significantly inlproved if the comparison is nlade to the two-thirds power of body weight instead of to weight directly. As was previously pointed out (5), the measurements reported by B r o d y and Elting (1) are similarly unaffected by substituting the two-thirds power for the direct body weight, as long as adult animals are being considered. On the other hand, when tile data of HogmL and Skouby (2), quoted by E]ting and Brody, are examined, it appears that a better correlation is obtained even in their adult animals when a power of body weight is used. This led the authors TABLE 5
Average measurements of fo~r body d imensioJ~s of Red Sindhi cattle in India as reported by Joshi a~d Phillips (3) Age 1 year I t e m of m e a s u r e n m n t
No.
Mean
2 years No.
(cm.) Height at withers D e p t h of f o r e e h e s t W i d t h of h i p s C i r c u m f e r e n c e of f o r e c h e s t
12 12 12 12
96.62 47.63 28.78 ] l 7.48
Mean
Mature No.
Mean
51 51 51 51
120.73 62.51 42.09 158.37
(c,~.) 12 12 ]2 12
106.02 60.96 33.43 133.99
(c,~.)
R. E. McDOWELL ET AL
2126
TABLE 6
S~mmary comparison of body measurements of Jerseys (herd average) and Sindhi-Jersey crosses at various ages I t e m of m e a s u r e m e n t
6 months
12 m o n t h s
18 m o n t h s
1st lactation
+ + + + + + + + + + + + + + .
0 + + + 0 q-+ . 0
0 0 + +
0 0 0 --0
H e i g h t at withers t I e i g h t at hips L e n g t h of leg (foreleg) Depth of forechest W i d t h of foreehest W i d t h of hil)s Width of pins Body length (withers to hips ) L e n g t h of rump Angle of r u m p (o) Total body length (withers to pins) Circumference of forechest C i r c u m f e r e u c e of p a u n c h
L e n g t h of head (poll to m o u t h ) W i d t h of head (width of eyes.)
.
.
.
. .
.
.
++
.
q. -.
.
++ . . + +
-{-+ + + ++ + +
.
.
. --. .
.
W-t. . 0
0
++ . --- - -
++ 0
++ --
++ ----
+ + Crosses significantly l a r g e r (1% level) t h a n J e r s e y . + Crosses significantly l a r g e r (5% level) t h a n Jersey. 0 Difference not significant. -- Crosses significantly smaller ( 5 % level) t h a n Jersey. ---- Crosses significantly smaller ( 1 % level) t h a n Jersey.
to subject their own as well as H o g a n and Skouby's data to a multiple regression analysis to determine what powers of body weight and total length fit the data best in the expression : A = K W~L b or L o g A = l o g K + a log W + b log L Where A is surface area, W is body weight, L is total body length (withers to pin-bones), K is a constant depending upon the units used, and a and b are power constants. The results of these analyses are given in Table 8. I t will be seen that the present authors' results differ considerably from those reported by H o g a n and Skouby. I t is believed that these differences cannot be attributed to differences in the teehlfique used for measuring surface area but nlust reflect real differences between the two groups of animals. I n adult Jerseys TABLE 7
Comparisons of surface areas and body weights and the relationships betu'ee~ surface area and body weight for 32 Jerseys and 23 Sindhi-Jersey (Fj) crossbred mat~tre cows Jersey Item Surface area (sq. m.) Body w e i g h t (kg.) S.A. (sq. c m . ) / B . W . ~ Correlation between S.A. and B.W. :Regression S.A. on ]~.W. S.A. (sq. c m . ) / ( B . W . ) °'°7 Correlation between S.A. and (B.W.) °'~: S u r f a c e a r e a / b o d y weight.
Value 4.26 454.97 94.44 0.715 0.0045 724.57 0.739
Sindhi-Jersey
Standard error 0.042 6.57 0.88 0.167 0.0008 4.43 0.161
Value 4.13 441.43 93.60 0.730 0.0050 712.03 0.749
Standard error 0.067 9.84 1.462 0.211 0.0011 8.15 0.206
.MEARUB~EMENTR
OF
,JEffREY
AND
('ROSSBI~ED
1427
CATTLE
TABLE 8 Powers of hotly weight al~d te~gth giving best fit in prediction for.m~das for s~trface area Using weight and length
Authors
Method of measuring surface area
}feDowell et al.
Surface integrator
Adult Jerseys
0.4795
0.0496
1790
"2277
iMcDowell et al.
Surface integrator
Adult SindhiJerseys
0.4821
-0.0916
3392
2189
I-Iogan and Skouby
Paper mould
Beef breeds of similar weight
0.2109
0.6651
504
I-Iogan and Skouby
Paper mould
All adult beef aninmls
0.3136
0.6523
286
Nature of cattle
Weight power (a)
Length power (b)
Constant (K)
Constant if length discarded (K')
and Sindhi-Jerseys the authors find total body length to have no significant relationship with surface area, whereas in the beef animals Hogan and Skouby found it to be more marked than the association of body weight with surface area. This nmy reflect basic differences between beef and dairy breeds, but it may be that the genetic u n i f o r m i t y of the dairy cattle studied by the authors minimizes the possible influence of body length and throws correspondingly into relief the influence of body weight. I f this supposition is true, then within a morphologically uniform breed a good estimate of the surface area could be obtained from the weight alone, preferably using the square root of the body weight as the basis of calculation. Before this is accepted, however, f u r t h e r studies should be carried out within uniform groups of beef animals and among more widely v a r y i n g breeds of d a i r y cattle. SUMMARY
Data are presented on comparative body weights, body dimensions, and "the measured surface area of Jerseys and Sindhi-Jerse~: (F1) crosses. The mean body weights of the erossbreds are greater than those of the Jersey dams at comparable ages and stages of lactation. This difference, which may be attributable to " h y b r i d vigor", in the crossbreds, is most evident from birth to 15 months of age. Body measurements made at 6, ]2, and 18 months of age and during first lactation show that at the earlier ages the crossbreds are taller and have greater body width and depth, but that their body length is less. With the advance o f age, the differences for most measurements, other than weight, between the two groups diminish to a nonsignificant value or actually become reversed. The crosses exceed the Jerseys, however, in angle of r u m p and length of head at all ages. The average coefficients of variation for body weight and body dimensions arc substantially the same for both groups.
1428
R. E. MeDOV,~ELL ET AL
T h e s u r f a c e a r e a w a s m e a s u r e d on 32 J e r s e y a n d 23 S i n d h i - J e r s e y c r o s s b r e d cows w i t h a s u r f a c e i n t e g r a t o r . T h e s e a r e a s w e r e c o m p a r e d w i t h b o d y w e i g h t s . N e i t h e r t h e r a t i o of s u r f a c e a r e a to b o d y w e i g h t n o r t h e r a t i o of s u r f a c e a r e a to t h e t w o - t h i r d s p o w e r of b o d y w e i g h t s h o w s a s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e two groups. ]n these animals a statistical analysis indicated that the surface a r e a is r e l a t e d to t h e s q u a r e r o o t of b o d y w e i g h t b u t to n o a p p r e c i a b l e e x t e n t to total body length. REFERENUES (1) BRODY, S., AND ELTIN(~, E. C. A Formula for Estimating Surface Area of Dairy Cattle. J. Agr. Research, 33: 3. 1926. (2') HOG.~, A. G., AND SKO,'BY, D. I. Determination of the Surface Area of Cattle and Swine. J. Agr. Researcl~, 25: 10. 1923. (3) Jos~tI, N. 1~., .~.~D PHILLIPS, 1~. W. Zebu Cattle of India and Pakistan. FAO Agrictdtural St~ldy No. 19, Rome, Italy. 1953. (4) M~TTHEWS, C. A. Standards for Normal Growth in Weights for Jersey Cattle. USDA TccL B~dI. (in press). (5) McDOWELL, R. E., L~E, D. H. K., _~'D FOHR~[_~N, M. It. The Relationship of Surface Area to Heat Tolerance in Jerseys and Sindhi-Jersey (F~) Crossbred Cows. J. Animal Sci., 12: 4. 1953. (6/ ~[CDO~VELL, R. E., LEE, D. H. K., FOHRMA~', M. H., SYKES, J. F., AND ANDERSON, R. A. Rectal Temperature and Responses of Jersey and Sindhi-Jersey F~ Crossbred Cows to a Standard Hot Atmosphere. J. Dairy Sci. (Submitted). (7) R.XTHORF,A. Differences in Growth of Red Sindhi and Crosses of Red Sindhi with Jersey, Brown Swiss, Holstein-Friesian, and Guernsey Cattle. Ph.D. thesis, low~ State College, Ames. 1949. /8) S~VETT, W. W., AND GRAVES, ~. R. Relation between Conformation and Anatomy of Cows of Unknown Producing Ability. J . . l g r . Besearel~, 58: 199. 1939.