Interbreed Matings in Dairy Cattle. I. Yield Traits, Feed Efficiency, Type and Rate of Milking1

Interbreed Matings in Dairy Cattle. I. Yield Traits, Feed Efficiency, Type and Rate of Milking R. E. M c D O W E L L ~ and B. T. M c D A N I E L

Animal Husbandry Research Division, USDA Beltsville, Maryland may have economic superiority over purebreds. Rates of milking and type scores showed little evidence of heterosis.

Abstract

Performance and efficiency in first lactation for 88 two-breed and 49 three-breed crosses among Ayrshires, Brown Swiss, and ttolsteins were compared to the weighted mean of purebred contemporaries of the three breeds to estimate heterosis resulting from crossbreeding. All possible combinations of two-breed and three-breed crosses were included. The animals were sired by 18 Ayrshire, 18 Brown Swiss, and 17 Holstein sires selected by random drawings from among all bulls of the three breeds in regular AI service. The two-breed crosses had 4 to 15% heterosis for days open. Ayrshire × Holstein and Swiss × Holstein crosses were 8 to 10% above the parental mean for production traits, but Ayrshire × Swiss showed no heterosis. Heterosis for measures of efficiency of feed utilization was about one-half that for production in Ayrshire × Holstein and Swiss × Holstein crosses, but was zero in Ayrshire × Swiss crosses. I n general, the estimates of heterosis for three-breed crosses were higher than for two-breed crosses. These were superior to the mean of the parental breeds by 13.8, 11.9, 13.8, 12.2, 9.2, 13.0, 12.9, 7.2, and 0.3% in days open in lactation, milk, fat, SNF, protein, FCM yields, therms produced, three measures of efficiency, and persistency of nfilk yield, respectively. The Ayrshires, Brown Swiss, and Ayrshire × Swiss crosses were significantly below Holsteins in production and efficiency traits. The Ayrshire × Holstein, Swiss × Holstein, and three-breed crosses were slightly lower in milk and FCM yields but generally superior to Holsteins in fat yield and efficiency. These results indicate certain crossbred groups Received for publication November O, 1967. This work is a paa't of the Southern Regional Dairy Cattle Breeding Project, S-49 (Genetic Methods of hnproving Dairy Cattle for the South). _oPresent address, Department of Animal Science. Cornell University, Ithaca, N. Y.

One means of improving the production by commercial dairy cattle through breeding is the possible use of heterosis resulting from interbreed matings. From evidence in other classes of livestock, one could anticipate that heterosis would be exhibited in several charaeteristics as a result of crossing dairy breeds. The critical and practical question, however, is whether crossbreeding will result in sufficient heterosis to provide greater economic returns than the best of existing breeds. It could also be anticipated that crosses between some breeds would yield results different from those crosses with other breeds. I n 1957, a study was initiated at the USDA Agricultural Research Center, Beltsville, Maryland, to evaluate interbreed matings among the Ayrshire, Brown Swiss, and Holstein breeds as a genetic method for improving the efficiency of nfilk production and modifying nfilk composition as well as other economic traits important in commercial dairy production. This report deals with the design of the study and a comparison of production traits and measures of efficiency between two- and three-breed crosses and contemporary purebreds for the first six years of the experiment. Experimental Procedures

Foundatio~ females. Forty, six- to eightmonth-old registered heifers of the Ayrshire, Brown Swiss, and Holstein breeds were purchased as foundation females. I n order that the animals would represent a variety of pedigrees, 13 of each breed were purchased in Ohio, 13 in Kansas, and the remainder in New York, Vermont, and New Jersey. No more than three animals were taken from a single herd and no paternal half-sibs were accepted from any herd. The heifers came from 85 farms, were out of 120 dams, and were sired by 105 bulls. The average age when the heifers arrived at Beltsville was 7.4 months. In addition to certain nfinimum requirements of size for age and of health, the dams of th~ 767

768

m c D O W E L L A N D MC D A N I E L

heifers were required to have a mininmm of one completed or extended fat production record on a twice-a-day milking, 305-day mature equivalent (ME) basis of 170, 195, or 197 kg for the Ayrshires, Brown Swiss, and Holsteins, respectively. These values were the 1952-56 D H I A averages for the three breeds. Beyond registry with the breed association, there were no specific requirements for sires of the heifers, but at the tinge of purchase about one-half the sires had tested progeny. The foundation females were assigned to four seemingly comparable outcome groups of approximately ten each based on farms, area of origin and predicted breeding value. Initial matings began with the first observed estrus following 15 months of age. The mating plan for each breed was carried out as illustrated in Figure 1 for Holsteins. The first- and second-generation matings were planned as indicated to provide comparisons between contemporary purebreds and two- and three-breed crosses in the same generations. Sires. Semen used on the foundation females and for all subsequent generations was obtained through the cooperation of the National Association of Animal Breeders. The bulls were selected by random in each of the three breeds from bulls in regular service during a given year and with at least ten tested daughters. Three sires of each breed were drawn per year. The restrictions were that only one bull per breed per stud per year

was accepted, and the bulls chosen could not be related in the first generation. Each sire was used for one year in the purebred and crossbred subgroups to provide contemporary paternal half-sibs. First- and second-generation progeny. All females that could be reared and that conceived were brought into production. The calves were separated from the dams shortly after birth and fed by hand in small pens. Whole milk was fed for the first month and then skimmilk or whole milk diluted with water n p to six months of age at the rate of one to ten of body weight with a maxinmm of 9 kg per day. From three weeks of age the calves were fed alfalfa hay and a small amount of concentrate mixture. The concentrate ration was gradually increased to a maximum of 1.4 kg daily by the time milk feeding was discontinued. After one month of age, the calves were shifted to comnmnity pens with individual feeding of milk and concentrate. The individual feeding of concentrates continued up through 12 months with hay fed ad libitum. After 12 months of age the heifers were reared in a loose housing' arrangement. They received 0.8 to 1.2 kg of concentrate per day, depending upon age, and hay and grass silage or pasture in season ad libitum. Between the 45th and 30th day prior to anticipated calving, the heifers were brought into a tie-stall nfilking barn where they received daily 3.6 kg of concentrates, 2.0 kg of alfalfa pellets along with

Grouping of FoundationFemales

2 odation Fooalos

Sires

3 I 10 I

1101

Ist Gem. Females

I Hol

I

I-Hol

Sires 2nd Gen. Females Sires

I Hol

iss

-~r

l-Swiss

I

I Hol

l

FIG. 1. Mating plan for each breed as illustrated for Holsteins. J. DAIRY SOIENOE ~OL. 51, NO. 5

-Ayr

-Hol

I-Hol

3rd Gen. Females

l l I

-Swiss

l-Hol

Y I E L D T R A I T S AND F E E D

ad libitum feeding of U.S. no. 1 alfalfa hay and corn silage. Three to five days before calving the animals were removed to box stalls in a maternity barn where they remained until the third day after calving, when they were returned to the milking barns. During lactation the cows were offered about 10% in excess of Morri~on's estimated net energy standards (9) to ensure they had ample. The cows were allowed to consume hay and silage to appetite. Concentrates were supplied to make up the difference between the estimated amount of energy consumed from forages and the calculated total i'equirements based on body weight, milk yield, and per cent fat. The cows were individually fed twice daily and refusals recorded on alternate days. Adjustments in the level of feeding were made at 15-day intervals during lactation. The animals were barn-fed throughout lactation. After completing one acceptable record at Bcltsville, the cows were loaned into Ayrshire, Brown Swiss, or Holstein herds in the nearby area. This step was taken to provide larger numbers than could be accommodated at Beltsville and to evaluate the project animals under commercial herd conditions. All cows loaned from the station remained in cooperator herds as long as they gave satisfactory performance. Through the fourth gestation, the cows were bred to the sires used in the experiment each year and the female calves were returned to the station within one week after birth for rearing and completing one satisfactory lactation. All females that conceived within 305 days after calving, irrespective of level of production, remained in the project for at least three gestations with none of the cows contributing offspring beyond the fourth gestation. This was done to minimize biases in the quality of dams contributing to subsequent generations and also to keep generation intervals as short as possible. During lactation, breedings were commenced at the first observed estrus following 70 days postpartum. The cows were bred for the first three services to one sire, with subsequent breedings being nmde to alternate sires from the pool available during that particular period. Any heifer not pregnant by 24 months of age was a nonbreeder and removed from the herd. Cows not pregnant by the 305th day of lactation also were removed. Trait codes. The following define the codes in the tables : Breed groups--Ayr, Ayrshire; Swiss, Brown Swiss; Hol, Holstein; A X H, Ayrshire X

EFFICIENCY

769

Holstein; S X H, Brown Swiss X Holstein; A X S, Ayrshire X Brown Swiss; A X SH, Ayrshire X (Brown Swiss X Holstein); S X AH, Brown Swiss X (Ayrshire X Holstein); and H X AS, Holstein X (Ayrshire X Brown Swiss). The two-breed grouping includes reciprocals and the sire of the three-breed crosses is identified by the first symbol of the series. Age--age at first calving in months. Days open--days from parturition to conception (up to 305 days). Milk yield--the sum of weights of individual nlilkings during first lactation. Fat, solids-not-fat (SNF), and protein yields were calculated from Babcock, Watson lactometer, and Orange G tests, respectively, of milk samples taken the 15th day of each month. Fat corrected milk (kg FCM) ----0.4 X milk -4- 15 X fat. Thel~ns produced (kcal 10~) were calculated by using constants for the therms in fat, protein, and lactose. TP ---- (4.132 X fat yield + 2.658 X protein yield -4- 1.792 X estimated lactose). The per cent lactose was calculated as % S N F - % protein-0.7% for ash. Therms/kg of milk were therms produced/ total milk yield. Per cent estimated net energy consumed (% ENE cons.) was the ratio of total therms ENE offered to the total therms consumed. The three measures of efficiency are : Eft. I -~ (total therms produeed)/(total thernls consumed); Eft. 2 ~ - ( k g F C M ) / ( t h e r m s ENE consumed) ; and Eft. 3 = (estimated milk protein yield)/(estimated feed protein consumed). Feed offered was adjusted at 15-day intervals during lactation by body weights which were the average of monthly weights. Gain was the difference between the last body weight during lactation period and the weight following the first full month in lactation. Persistency of" milk yield =: [(milk yield second 150 days)/(yield first 150 days)] X 100. Compa~rative milking rate was studied from recordings of time fronl attachment of the teat cups to start of strip, total milking time, twominute yields, kg/minute to start of strip, and kg/minute for the total period. These were recorded for two successive afternoon milkings between the 90th and the 120th day of first lactation. The average of the two-day results characterized milking rates for the individual cows.

A modification of the dairy type appraisal system developed by the Extension Division of the Department of Animal Science, Cornell University (1), was used to score 21 cornJ, DAII=~Y SCIENCE ~]-Oh. 51, NO. 5

770

MC D O W E L L A N D I~IC D A N I E L

ponents of type. The same scoring system was used for all breed groups. The scorings were made between the 90th and the 120th day of first lactation by comparing the animals to descriptive ratings or diagrams depicting gradations from the most desirable to the least desirable. Condition grades were used to characterize the degree of fleshing following the procedure suggested by Lee (5). All scorings were made independently by two appraisers prior to the afternoon milking and the averages used as the score for the individual cows. The variance of nmst traits was analyzed by least squares to measure differences between breed groups adjusted for year and season of calving. Six two-month seasons were used for each year. The following nmdel was employed: Y~j~z z tL + t, + sj + bk + eukz Where t' ---- population average t~ = effect due to i TM year of calving s~ ----effect due to j~h season of calving bk ~- effect due to k TM breed group Regressions of production traits on age at calving and days open were also included in preliminary analyses. However, inclusion of the regressions slightly increased most error mean squares, because the degrees of freedom decreased relatively faster than the sums of squares adjusted for regression, therefore, they were deleted from the analyses presented. Duncan's ~iultiple Range Test separated breed groups differing significantly. In other cases Chi-square analyses tested the significance of the deviation of the crossbreds from parental mean on the basis of additive genetic variance. All acceptable production records for calvings from 1961-66, irrespective of length, were analyzed. These included both normal and projected satisfactory records. A normal record was a complete record of up to 305 days or one which had been terminated earlier because daily milk yields were below 4.5 kg for ten days without any recording of abnormalities or health conditions being noted which would influence performance. Records projected up to a 305-day basis were used in place of the actual records where identified health problems caused a change in daily milk yield of 25% or more for three days or longer and it was evident from the daily milk yields that the influence of the disturbance or the treatment used persisted for ten days or more. I f the point of disturbance occurred later than 30 days in lactation, the record was projected with standard D H I A projection factors (7) from the last normal day to a 305-day basis and compared to the actual record. When the ~. DAIRY SCIENf'E ~¢~OL. 51, NO. 5

difference exceeded ± 1 3 % , the projected record was used. This followed the procedure recommended by MeDaniel et aL (6). There were two Ayr, one Swiss, two I.iol, one A X H, two A X S, one S X A H , and one H × AS where projected records were used. I f a point of serious disturbance occurred in the first 30 days of the lactation, the record was declared unsatisfactory. The cow was dried off and held for a second lactation. The completed second record was regressed to the age of first calving by the ratio of the Dai~T Herd Improvement Association conversion factors (8). Four of the cows (one each of the Hol, A x H , A X S, and H X A S groups) which calved for first lactation failed to attain a normal or projected acceptable record. Of these, one died in less than 30 days, one was killed following parturition paralysis, and two failed to rebreed for a second lactation after having an incomplete 30-day record in first lactation. The current analyses deal only with first lactation records. Subsequent lactations completed in the cooperating commercial dairy herds will be dealt with in a later report. Results and Discussion

Dams of foundation females. In the planning and conduct of the investigations, efforts were made to obtain as nearly comparable samples of each breed as possible, to use animals with potential merit of breed average or above, and to provide the best practical environment for rearing and first lactation. In Table 1 are the average number of records and the mean 305day mature equivalent milk yields for lactations completed by the dams of the foundation females prior to the purchase of the heifers. Also in the table are the average per cent deviations from herdmates for the foundation Ayrshire, Brown Swiss, and Holstein cows along with the average per cent deviations of their records from the 1951-56 D H I A breed averages for milk and fat yields. These data show that although only minimums were specified for one or more fat production records, the purchased heifers were from dams with very sinlilar rankings in relation to their respective breeds. FouNdation females. Of the 40 females that were purchased per breed, 30 Ayrshires, 39 Brown Swiss, and 38 Holsteins completed acceptable first lactation records in the Beltsville herd. The means and standard errors for various traits on them are presented in Table 2. The average age of calving was similar for all breeds, but there were significant differences among breeds in days open, with Brown Swiss

YIELD

TRAITS

AND

TABLE 1. Average milk and f a t yields for dams of the heifers purchased as foundation animals. Breed of dam

Avg no. records/cow" Milk (kg) b F a t (kg) b % Dev. from herdmates, milk ° % Dev. from herdmates, fat ° % Dev. from breed avg, milk a % Dev. from breed avg, fat a

Ayrshire

]~rown Swiss

/-Iolstein

3.6 4,911 200

2.4 5,264 224

2.3 6,341 232

-t-14.7

-t-11.7

-~-16.7

~17.9

~14.9

-~17.2

-F-18.5

-{-15.1

-~16.2

-{-19.2

-]-20.7

~-18.8

" Average number records completed prior to time of purchase of daughters. b Three hundred and five-day mature equivalent (ME) of all records completed prior to purchase of daughters. The age conversion factors used came from (4). I.ierdmate a,verages were computed as 1.1 X the yearly DI-IIA averages. a Average per cent deviation of dams from 1951-56 D H I A breed average (ME). h a v i n g the least. The H o l s t e i n s were significantly above the two o t h e r breeds in yield t r a i t s - - m i l k , fat, f a t corrected milk, a n d solids-not-fat. The p e r cent estimated net energy consumed was v e r y n e a r l y the same f o r each breed, b u t the B r o w n Swiss were lower ( P < .01) in efficiency. B r o w n Swiss were highest in persistency a n d weight gain d u r i n g lactation. The a v e r a g e p e r cent deviation of the f o u n d a tion cows f r o m the 1958-61 D a i r y H e r d Ira-

FEED

771

EFFICIENCY

p r o v e l n e n t Association breed a v e r a g e s showed t h a t the A y r s h i r e s a n d H o l s t e i n s r a n k e d a b o u t the same in r e l a t i o n to the c o n t e m p o r a r y b r e e d averages as did t h e i r dams, while the B r o w n Swiss fell slightly below breed average. The lower p e r f o r m a n c e of t h e B r o w n Swiss was due in p a r t to the lower a v e r a g e yield of the g r o u p o r i g i n a t i n g f r o m Ohio. A l t h o u g h the dams of this s u b g r o u p r a n k e d a b o u t the same in relation to breed a v e r a g e as those f r o m the o t h e r areas, t h e i r a v e r a g e p e r f o r m a n c e was a p p r o x i m a t e l y 500 kg below t h a t o f the K a n s a s a n d N o r t h e a s t Swiss. Differences f r o m area of origin were v e r y small in the two o t h e r breeds. Sires. There were 18 A y r s h i r e , 18 B r o w n Swiss, a n d 17 H o l s t e i n sires which c o n t r i b u t e d p r o g e n y in the c u r r e n t analyses. Based on D a i r y H e r d h u p r o v e m e n t Association sire summaries m a d e in J a n u a r y , 1967, the a v e r a g e predicted differences f o r milk a n d f a t were 59 kg, 2 k g ; 5, 2; a n d --37, - - 2 f o r the A y r s h i r e , B r o w n Swiss, a n d H o l s t e i n bulls, respectively. The a v e r a g e n u m b e r of d a u g h t e r s p e r sire was 183 f o r Ayrshires, 156 f o r B r o w n Swiss, a n d 546 f o r Holsteins. The n u m b e r of d a u g h t e r s r a n g e d f r o m 26-668, 23-688, a n d 17-1675 f o r Ayrshires, B r o w n Swiss, a n d Holsteins, respectively. These values indicate the average predicted differences were n e a r breed a v e r a g e in all three breeds. The mean predicted differences f o r the sires weighted a c c o r d i n g to the actual n u m b e r of d a u g h t e r s c o n t r i b u t e d to the p u r e b r e d a n d crossbred g r o u p s are shown in Table 3. A l t h o u g h the sires used the first two y e a r s c o n t r i b u t e d only p u r e b r e d a n d two-breed p r o g e n y , there was no i n d i c a t i o n t h a t these were different in quality from the sires which h a d a n o p p o r t u n i t y to c o n t r i b u t e offspring to all three m a j o r g r o u p i n g s . There is some r a n g e in the estimated b r e e d i n g values of sires, b u t

TABLE 2. Means and standard errors for performaace traits of foundation purebreds in first ]aetntion. Breed groups Trait code

Ayrshire

Brown Swiss

Holstein

No. of lact. Age calving (months) Days open Days in lact. Milk (kg) F a t (kg) SNF (kg) FCM (kg) % E N E cons. Eft. 2 Gain (kg) Persist. ( % ) % Dev. from breed avg, milk ~ % Dev. from breed avg, fat S

36 25.5 -+ .04 174 -+ 12 301 ± 2 3,879 ±106 ]61 -+- 5 350 -+ 9 3,972 _ 1 0 7 102.1 ~ .47 0.80___ .07 60 -+ 3.9 67 ± 2 -{-13.4 -[-10.5

39 25.6 -+ .03 ]38 -+ 13 299 ± 5 3,387 ±123 ]48 _ 17 316 -+ 11 3,565 _+130 105.3 ___ .94 O.67-+ .O2 98 ± 4.1 74 -+ 2 --2.4 --1.0

38 24.9 ~ .04 152 ± 13 302 _+ 2 5,007 ±162 J88 -+ 6 435 -+ 13 4,800 ~149 103.3 ~ .67 0.8t)± .01 89 -+ 4.2 69 -+ 2 -~16.9 ~-18.6

Average per cent deviation of ME first lactation yields from 1958-61 D H I A breed a~erage. J. DAIRY SCIENCE VOL. 51, NO. 5

772

,'~C D O W E L L A N D MC D A N I E L

TABLE 3. Summaxy of average predicted differenees ~ for sires weighted by contribution of female progeny to each subgroup.

~~0.

:Breed of sire Ayrshire Ayrshire Ayrshire Ayrshire

:Breed of dam Ayrshire Swiss Holstein SX H

of offspring 28 16 14 17

Avg pred. diff. of sires ~ weighted by no. offspring Milk --(kg)-28 57 50 92

Fat 1 3 2 5

Swiss

Swiss

34

--18

1

Swiss Swiss Swiss Holstein Holstein Holstein Holstein

Ayrshire Holstein A X H Holstein Ayrshire Swiss A X S

16 12 8 27 18 12 24

--14 --60 60 --72 43 --35 --112

1 3 4 --4 2 --2 --3

'~D H I A pred. diff. ~--

n

- [Dau. avg -- H.M. n+20 avg) + 0 . ] ( H . M . avg -- breed avg)]. ~Based o~ January, 1967, DH]:A Sire Summary.

this seems no greater than would be expected with the limited number of animals in each breed group. These data show that the average productive potential of the sires and foundation females was near their respective breed average. P u r e b r e d s v e r s u s crossbreds. The least squares means and standard errors for first lactation performance traits of Ayrshires, Brown Swiss, Holsteins, and two-breed and three-breed crosses are in Table 4. Year effects were generally low and nonsignificant; however, season effects on production traits and measures of efficiency were statistically significant. Cows calving from May through October averaged about 10% lower in yields and efficiency measures than those calving f r o m November through April. Breed effects were also imp o r t a n t f o r all yield traits and efficiency measures. The average coefficients of variation f o r all purebreds and two-breed crosses were similar, indicating that variability in the performance of crossbreds was no less than for purebreds. The three-breed crosses had higher coefficients of variation, which could be expected because of the small numbers in the groups. The means ranked and separated by Duncan's Multiple Range Test are shown for most of the traits in Table 5. The codes for breed groups are arranged to show the rankings f r o m high to low; i.e., Holsteins were the J. DAIRY SCIENCE VOL. 51, NO. 5

highest in milk yield, the S × A H were highest in fat yield, and Brown Swiss had the greatest number of days open. All the crossbred groups averaged less days open than purebreds, but the differences among breed groups were not statistically significant. Also, breed differences were not i m p o r t a n t in age of calving, days in lactation, persistency of milk yield, or the average body weight gain during lactation. F o r milk, fat, solids-not-fat, protein, fat corrected milk, and therms produced there were two distinct groupings. The Ayrshires, Brown Swiss, and A X S crosses were significantly lower than the six other groups. These groups were, however, equal to or higher than the rest in therms per kilogram of milk and weight gains. The Brown Swiss gained the most body weight and produced milk with the highest energy content. The differences in yield traits among purebred Holsteins, two-breed crosses with half Holstein inheritance and all the three-breed crosses were small and nonsignificant. The A × H, S × H, and three-breed crosses were generally superior to all purebreds in the three measures of efficiency (Eft. 1, 2, and 3). The variation in energy content of the milk between these groups and Holsteins compensated f o r the 4 to 7 % lower total milk yield. Estimates of heterosis for the two-breed crosses, expressed as the average p e r cent deviation from the parental mean, are shown in Table 6. The parental mean was derived f r o m one-half the sums of the means for the particular p a r e n t breeds. These values indicate 4 to 15% superiority over the parental mean for the crossbreds in days open and a positive heterosis of 8 to 10% for production traits in A × H and S × H crosses. Heterosis for production traits in A × S crosses was near zero or slightly negative (--0.1 to - - 1 . 7 % ) . The level of heterosis f o r measures of efficiency was about half that for production traits in A × H and S × H crosses but again near zero in the A × S crosses. The average heterosis of a p p r o x i m a t e l y 6% for lactation traits is in general agreement with estimates from six other studies of two-breed crosses reviewed by Pearson and ~V[cDowell (11). However, to use only an average figure for expected heterosis from two-breed crosses would be nfisleading to the potential user, since f r o m Tables 4 and 6 level of performance and the amount of heterosis are quite different when the Holstein breed is one of the parents. The estimates of heterosis f o r the three-breed crosses are expressed two ways in Table 7. The per cent deviations f r o m the theoretical contributions of the purebreds (P) measured

TABLE 4. L e a s t squares means and standaxd errors for p e r f o r m a n c e t r a i t s of Ayrshircs, Brown Swiss, Holsteins, and two-breed and three-breed crosses in first lactation. Breed g r o u p s T r a i t code No. of lactations Age ( m o n t h s ) Days open

Ayrshire

]~rown Swiss

28

Holstein

34

A X H

27

S X H

32

26.3 ±

.07

25.5 ±

.06

25.9 ±

.08

133 ±

10

146 _

9

139 ±

11

26.8 ± 115 ___

A X S

24

A X SH

32

S X AH

17

H X AS

8

24

.07

26.4 +

.08

26.0±

.07

26.6±

.10

26.6___ .14

25.8___ .O9

10

126 _

11

133±

10

129±

14

106±

124-+-

11

~

304±

5

~

19

Days in lactation

305 ±

4

297 ±

4

305 ±

4

305 _

4

305 ±

5

297±

4

303±

6

304±

8

Milk ( k g )

4,084 ±

165

4,017 ±

149

5,345 _

171

5,100 ±

158

5,142 ±

180

4,026+

159

5,004±

219

5,070±

311

]?at ( k g )

171 ±

7

174 ±

6

204 ±

7

6

209 ±

7

173~

7

205±

9

212...

13

SNF (kg)

371±

15

376±

13

469±

15

452~

14

466±

16

371...

14

448---

20

461±

Protein (kg)

140 ±

5

142 ±

5

169 ±

5

163 ±

5

6

139±

5

165±

7

170±

FCM ( k g )

4,199 ±

165

4,228 ±

148

5,194 ±

170

5,070 ±

157

5,192 ±

179

4,201±

158

5,080±

219

T h e r m s prod.

3,172 ±

123

3,230 ±

111

3,874 ±

127

3,786 ___ 117

3,923 ±

133

3,188±

118

3,809_____ 163

.77 ±

•01

.79±

.01

98.0 ±

1.2

Therms/kg milk

202 ___

.77 ±

.01

.81 ±

.01

.73 ±

.01

% E N E cons.

98.1 ±

1.1

97.6 ±

1.0

97.3 ±

1.2

Eft. 1

.594 ±

.01

.557 ___ .01

Eft. 2

.79 ±

.02

.73 ±

.02

.82 ±

.02

.84 ___ .02

.81 ±

Eft. 3

.312 ~

.01

.286 ±

.01

.314 ±

.01

.322 ___ .01

.318 ±

Gain ( k g )

65.3 ~

5.9

85.3 ±

5.4

74.4 ±

6.4

64.0 ___ 5.9

70 ±

3

3

77 ~

3

Persist. ( % )

80 ___

.610 ___ .01

.75 _--_ .01

171

99.2 ±

1.1

.628 ___ .01

74 ___

3

208---

8

27

455---

16

10

165±

6

5,208--- 311

5,095±

185

3,928--- 231

3,857--- 137

5~

.01

.77__

.01

.79±

.O1

~

97.3+___ 1.1

98.9_____ 1.5

98.0---

2.2

98.9---

1.3

¢~

.574---

.01

.628±

.02

.631±

.03

.635_____ .02

.02

.76±

.02

.84---

.02

.84_____ .04

.84±

.02

•01

.293±

.01

.321±

.01

.326_____ .01

.322±

.01

78.5 ±

6.4

80.8---

5.9

59.0---

8.2

72.2±11.3

73.5±

6.8

82 ±

3

.613 ___ •02

Eft. 1 ~ (total t h e r m s p r o d u c e d ) / ( t o t a ] t h e r m s consumed) ; Eft. 2 ~-- (kg F C M ) / ( t h e r m s (estimated feed protein consumed).

78± ENE

3

.77__

4,952___ 185

75±

4

c o n s u m e d ) ; Eft. 3 z

72±

5

80___+

(estimated milk protein y i e l d ) /

774

Mc DOWELL AND lViCDANIEL

TABLE 5. D u n c a n ' s R a n g e T e s t for breed g r o u p ~ a v e r a g e s of nlost p e r f o r m a n c e t r a i t s r a n k e d f r o m h i g h to low.

Milk b 3 5 4

Fat

SNF

8

3

7 4 6

]

7 2 1 6

FCM

Persist.

Therms.Therms/ prod. k g m i l k Eft. 1 8

3 5

5 8 9 4

8 9

Protein

7

Gain

4 7

9

3 4

8 2

7 4

9 8

5 ]

1

7 6 2

6 3 9

i 1

Age ca].

1

0

6

Days in laet. 5

I

5 3

2

Eft. 2

Days open

2

7

Connected vertical lines indicate no significant difference. ~ B r e e d g r o u p s : 1, A y r ; 2, Swiss; 3, H o l ; 4, A X H ; 5, S X H ; 6, A X S ; 7, A X S H ; 8, S X A H ; 9, H X AS. b Milk, Hol h i g h e s t a n d B r o w n Swiss lowest; days open, Swiss g r e a t e s t n u m b e r d a y s w i t h S X A H least. t h e t o t a l h e t e r o s i s f o r t h r e e - b r e e d crosses. T h e expected purebred average was: P= (1/2) ( b r e e d o f s i r e ) -5 ( l ~ ) ( b r e e d of maternal grandsire) + (l~)(breed of maternal grandam). Estimates of heterosis over the true parents are indicated as TP. The TP average is b a s e d o n t h e a v e r a g e f o r t h e b r e e d o f sire and the two-breed crossbred dam group. Estimates of heterosis for three-breed c r o s s e s , e x p r e s s e d e i t h e r a s P or T P , w e r e generally higher than for two-breed crosses, b u t t h e w a y t h e t h r e e - b r e e d c r o s s is p u t together influences the degree of heterosis. However, t h e close s i m i l a r i t y o f t h e m e a n s f o r t h e t h r e e - b r e e d g r o u p s in T a b l e 4 s u g g e s t s t h e d i f f e r e n c e s i n h e t e r o s i s c o u l d be a t t r i b u t e d to s o m e e x t e n t to t h e 5 0 % H o l s t e i n w e i g h t h l g in t h e P - v a l u e f o r H X A S c r o s s e s as c o m p a r e d to 2 5 % i n t h e t w o o t h e r g r o u p s . TABLE 6. A v e r a g e p e r cent deviation of two-breed crosses f r o m p a r e n t a l m e a n f o r p e r f o r m a n c e traits

TABLE 7. A v e r a g e per c e n t deviation for threebreed crosses f r o m p r o p o r t i o n a l w e i g h t e d m e a n of p u r e b r e d s a n d m e a n of true paxents

T r a i t code

T r a i t code

A X It

S X H

A X S

D a y s open D a y s in l a c t a t i o n Milk Fat SNF Protein FCM T h e r m s prod. T h e r m s / k g milk % E N E cons. Eft. 1 Eft. 2 Eft. 3 Gain Persist.

--15.0 --0.1 8.1 7.9 7.5 5.3 8.0 7.4 --1.1 1.5 4.8 4.3 2.9 --8.2 0.8

(g/r) --11.6 1.9 9.9 10.4 10.4 10.5 10.2 10.4 --0.4 0.4 4.9 5.1 6.0 --1.8 4.1

--4.2 --1.4 --0.7 --0.1 --0.6 --1.7 --0.3 --0.4 0.8 --0.6 0.0 --0.3 --2.0 7.0 3.9

Breed groups Comparison A X SI-I S x A H tt XAS (%)

D a y s open D a y s in lactation Milk Fat SNF Protein FCM T h e r m s prod.

Breed groups

J. DAIIgy SCIENCE VOL. 51, NO. 5

T h e e s t i m a t e d a v e r a g e h e t e r o s i s f o r f a t corrected milk yield of two-breed and three-breed crosses was about 6 and 14%, respectively,

Therms/kg milk qv E N E cons. Eft. 1 Eft. 2 Eft. 3 Gain Persist.

P~ TP b P TP P TP P TP P TP P TP P TP P TP P TP P TP P TP P TP P TP P TP P TP

--6.2 --0.3 --0.2 --I.i 14.1 8.4 14.0 8.1 12.9 6.9 14.9 11.8 14.0 8.2 13.3 7.4 --1.5 --4.3 1.1 0.9 7.4 4.8 6.6 4.0 5.0 2.0 --19.0 --18.1 1.4 --0.7

--24.7 --18.8 0.9 0.9 ]6.1 11.2 17.1 12.5 15.7 ]1.3 6.4 7.2 16.7 12.0 16.3 12.0 --0.7 --0.2 0.3 --0.4 9.4 6.7 8.9 6.5 8.6 7.0 --7.4 --3.8 --5.7 --6.0

--10.5 --8.6 0.4 1.I 5.4 5.7 10.3 10.3 8.0 8.3 6.4 7.2 8.3 8.4 9.0 9.2 2.9 2.4 1.4 1.7 6.6 6.6 7.2 7.3 5.0 6.1 --2.1 --5.4 5.2 3.2

P _-- a v e r a g e d e v i a t i o n f r o m w e i g h t e d p u r e b r e d mean. b T P ---- (one-half) (breed of sire -5 crossbred dam).

YIELD TRAITS AND FEED EFFICIENCY but it is not clear how much of the difference between the values is attributable to heterosis in the two-breed dam and to that attained by adding the third breed. In the experiments reviewed by Pearson and McDowell (11), three of five studies indicated the third breed decreased the relative advantage of crossbreds in first lactation milk yield. However, results reported by Johnson et al. (3) involving the three-breed crosses among Jerseys, Brown Swiss, and Holsteins support the findings of the current study in that the heterosis from adding the third breed was approximately double the amount the two-breed crosses exceeded the average of the purebred parents. Based on the actual means (T~ble 4), about all that can be said is the three-breed crosses were about equal to the two-breed crosses with onehalf Holstein breeding. According to results of Bereskin and Touchberry (2) in crisscrosses with Holsteins and Guernseys, introducing a third breed maintains more of the heterosis attained in the two-breed cross than backcrossing to one of the parent breeds. There are suggestions of differences in combining ability among the three breeds (Tables 4, 6, and 7 ) ; however, this may be due more to the marked difference in level of milk yield between Holsteins and the two other breeds than true heterosis per se. Sufficient data to evaluate results for reciprocal crosses separately would further clarify whether maternal effects are involved. Variation in combining ability among sires of the same breed has been indicated by Bereskin and Touchberry (2) and Okumu and Berry (]0), but such effects probably cannot be measured precisely in this study due to the small number of sire progeny per breed group. The question of greatest interest is whether the crossbreds might be more profitable than the better of the available purebreds. In Table 8 are presented the average per cent deviations

775

for Ayrshires, Brown Swiss, and the six crossbred groups from the means for contemporary Holsteins. The Ayrshires, Brown Swiss, and A × S crosses were significantly below the Holstein mean in production and efficiency traits. The A × S, S × H, and three-breed crosses were slightly lower in milk and F CM but generally superior in fat yield and the three measures of efficiency. In terms of milk production alone the advantages favor the Holsteins. On the other hand, in some costprice situations, particularly where greater economic emphasis may be given to milk composition and efficiency of feed utilization, there could be advantages for the crossbreds. Evaluation of the suggested increased net economic merit of the crossbreds will be considered in a subsequent report. Rate of milking. Milking rates were charactel~ized by measures of time from start of milking to start of stripping, total milk time, 2minute yield, kg/minute to start of strip, and kg/minute for the total milking period. Data on eight breed groups were subjected to two least squares analyses of variance. In this phase of study the foundation purebreds were included to increase the confidence in the means for the purebreds. Only two groups of three-breed crosses were considered due to the small numbers in the S X A H group. In Analysis l, only effects of year and stage of lactation were considered. This analysis gave significant F-values (P < .01) for year in all measures and for breed groups in the three yield measures, but the F-values for days in milk were significant (P < .05) only in total time and kg/minute for the total milking period. The year effects were gross, since they were confounded by such things as changes in milkers and recorders. The means from least squares for the breed groups are given in Table 9. There is some evidence of heterosis for the three traits listed

TABLE 8. Avera:ge per cent deviation of some traits for two purebred aald six crossbred groups from mean for contemporary Holsteins Traits Groups

Milk

:Fat

FCM

:Prorein

Ayrshire Swiss AXS A X tt SXH A X SH S X AH H X AS

--23.5 --24.8 --24.7 --4.6 --3.8 --6.4 --5.1 --7.4

--16.2 --14.3 --15.2 --0.9 2.6 0.7 4.0 1.0

--19.2 --18.6 --19.1 --2.4 --0.1 --2.2 0.3 --1.9

--16.6 --15.8 --17.7 --3.4 1.8 --1.8 1.0 --2.3

Therms prod.

Eft. 1

Eft. 2

Eft. 3

(%)--18.1 --16.6 --17.7 --2.3 1.6 --1.7 1.4 --4.4

--2.6 --8.6 --5.9 2.9 0.6 2.9 3.5 4.2

--3.9 --]0.8 --7.4 2.8 --0.7 2.4 2.4 2.6

--0.6 --8.9 --6.7 2.5 1.3 2.2 3.8 2.5

J. DAIRY SCIENCE VOL. 51, NO. 5

776

~c

DOWELL

A N D MC D A N I E L

TABLE 9. B r e e d g r o u p l e a s t s q u a r e s m e a n s a n d s t a n d a r d errors f o r m i l k i n g r a t e derived by two analyses a t~reed group

No. la.et.

Ayrshire Swiss Holstein A X H S X H A X S A X SH H X AS

61 70 63 32 24 29 13 23

T i m e to strip (rain) Anal. 1 3.69 3.78 3.90 4.04 4.15 3.51 4.52 4.24

+ ± ± _~ ± ~ ~ ±

K g / m l n to strip

Anal. 2

.19 .17 .19 .24 .27 .25 .37 .29

3.86 4.11 3.65 3.82 3.97 3.60 4.43 4.10

Anal. 1

± .18 ± .17 ± .18 ± .23 ± .25 _+ .24 _+ .35 ~ .27

1.74 1.56 2.17 2.07 1.93 1.85 1.71 1.86

± .09 ___ .08 ± .09 ___ .11 ± .12 -4- .11 ± .17 ± .13

1.86 1.75 1.99 1.92 1.84 1.93 1.65 1.80

A u a l y s i s 1, c o n s t a n t s fitted f o r y e a r a n d d a y s in milk only; d a y s in milk, a n d linear a n d q u a d r a t i c effects of yield. (Analysis 1), but the patterns are inconsistent. H e t e r o s i s w a s s u g g e s t e d in t h e A × H a n d S X t t f o r all t h r e e t r a i t s (3.5 to 8 . 0 % ) , b u t the mean for A × S was below expected by 5 to 7 % in t w o t r a i t s . T h e t h r e e - b r e e d c r o s s e s w e r e also i n c o n s i s t e n t , in t h a t b o t h g r o u p s w e r e a b o v e t h e p a r e n t a l m e a n in t i m e b u t b e l o w in t h e m e a s u r e s o f y i e l d p e r u n i t o f t i m e . I n A n a l y s i s 2, l e a s t s q u a r e s c o n s t a n t s w e r e fitted f o r y e a r , d a y s in m i l k , a n d t h e l i n e a r a n d q u a d r a t i c effects o f yield. T h e m o s t i m p o r tant variables in this analysis were year and yield. B r e e d g r o u p effects w e r e n o t s i g n i f i c a n t for any traits. The least squares means (Table 9, A n a l y s i s 2) i n d i c a t e little e v i d e n c e o f b e t -

K g / m i n f o r total period

Anal. 2

Anal. 1

~ .08 ~ .07 + .08 ~ .09 ~ .11 ~+ .10 ± .15 ~ .11

1.50 1.35 1.84 1.75 1.70 1.54 1.45 1.59

Anal. 2

~ .07 ~ .06 ~ .07 ± .09 ~ .10 ~ .09 __+ .14 <- .10

1.60 1.52 1.69 1.62 1.61 1.62 1.39 1.54

+ ± ± ± ± ± ± ~

.06 .05 .05 .07 .08 .08 .11 .09

A n a l y s i s 2, c o n s t a n t s fitted for year,

e r o s i s f o r m i l k i n g r a t e . T h u s , w h e n level o f m i l k y i e l d is c o n s i d e r e d , m i l k i n g r a t e s o f crosses among Ayrshires, Brown Swiss, and Holsteins are near the expected parental mean. Type appraisal. T h e o b j e c t i v e s o f t h i s p h a s e o f i n v e s t i g a t i o n w e r e to e v a l u a t e t h e i n h e r i t a n c e of body characteristics commonly associated w i t h t h e t h r e e p u r e b r e e d s , i.e., s t r o n g p a s t e r n s in B r o w n S w i s s a n d u d d e r s h a p e i n A y r s h i r e s ; a n d to d e s c r i b e t h e g e n e r a l d a i r y t y p e s c o r e s o f c r o s s b r e d s in r e l a t i o n to p u r e b r e d s . The m e a n s f o r 18 c o m p o n e n t s o f t y p e a n d o n e m e a sure of fleshing for the nine breed groups are g i v e n in T a b l e 10. T h e l o w e r t h e m e a n t h e m o r e it a p p r o a c h e d t h e d e s i r e d t y p e . I n m o s t

TABLE 10. B r e e d g r o u p m e a n s f o r c o m p o n e n t s of t y p e ~ for p u r e b r e d s a n d crossbreds w i t h t e s t s of significance of deviation f r o m p a r e n t a l m e a n s Trait code No. a n i m a l s Condition grade Dairy character Withers Back Rump Hindlegs, side rear Pasterns Barrel depth Udder, depth Shape, fore rear Levelness Attach., fore rear H e i g h t , rear H a l v i n g , reax Quartering, side Teat placement

Breed groups Ayr

Swiss

Hol

65

72

67

A X H 32

S X H 24

A X S 29

A X SH 15

S X AH 8

I-I X A S 25

5.2

7.0

5.5

5.8

6.8*

6.8**

6.3**

6.8 ~*

6.6

1.9 1.3 1.8 3.2

2.7 1.9 2.4 3.4

1.8 1.3 2.4 3.1

1.6 1.3 2.1 2.7

2.8 ** 1.9 ~ 2.1 2.7

2.4 *~ 1.9 ~* 2.1 2.2

2.1 1.3 2.2 2.9

2.4 ~* 1.8"* =.,° o 2.7

2.0 1.4 2.0 2.7

1.6 1.8 1.8 1.8 1.7 1.9 2.1 1.5 1.6 1.6 1.6 1.9

1.1 1.2 1.2 2.0 2.3 2.4 2.7 1.8 1.6 2.1 2.3 2.0

1.5 1.7 1.7 1.7 1.7 2.0 2.2 1.8 1.9 1.7 1.7 1.8

1.6 1.9 1.4 1.7 1.9 1.5 2.1 1.7 1.4 1.6 1.6 1.6

1.0"* 1.2 1.1"* 2.0 2.0 2.4 ~* 2.6 2.1 1.7 1.9 2.2 1.9

1.1 1.4 1.1 ~* 2.1 2.1 2.2** 2.7 2.3 1.6 1.9 2.4 2.0

1.6 1.7 1.4 1.8 i,'.0* 1.8 2.3** 1.8" 1.8 1.7 1.7 1.7

1.3 1.5 1.0"* 2.0 1.9 2.1 ** 2.6 ~ 1.8 :*~ 1.4 1.8 2.0 1.8

1.5 1.7 1.3"* 1.7 1.7 2.0 2.2 1.6 ~ 1.5 1.6 1.7 1.6

1.5

2.1

1.5

1.3

1.8

2.0

1.5

1.7

1.5

1.9

3.0

2.4

2.1

2.5

2.6

1.7

1.7

2.1

B a s e d on s c o r i n g of 1,2,3, etc., with low v a l u e s reflecting m o s t desirable. * P r o b a b i l i t y of Chi-square Xe value < 0 . 0 5 ; ** p r o b a b i l i t y of Chi-square X-" < 0 . 0 1 . J . DAIRY SCIENCE "(¢~OL. 51, ~O. 5

Y I E L D T R A I T S AND F E E D E F F I C I E N C Y

instances there was a skewness in the distributions within groups tending toward the low scores. Thus, the frequency of the less desirable types is not well reflected in the group means. Chi-square tests compared distributions o f scores f o r each trait in crosses to the unweighted averages of the parental purebred means, to determine if the distributions for the crossbred groups deviated more than would be expected by chance. The parental means f o r two- and three-breed crosses were computed in the same fashion as for traits previously discussed. E x c e p t for some udder traits the means for the Ayrshires and Holsteins were similar. The Brown Swiss was the most divergent purebred group. They were highest in degree of fleshing and rated best in shape of hindlegs and strength of pasterns, but in general they had the poorer scores in other traits. The means for the crossbred ~ ' o u p s suggest some degree of nonadditive genetic effects in a few traits such as pasterns and shape of fore-udder, but in most cases the variations a p p e a r additive. The crosses tended to carry more flesh than the mean of the parents. This resulted in slightly lower than expected scores in dairy character. The crossbred groups were all above the parental mean in pastern scores and some udder traits, but in general the t y p e scores of the crossbreds were similar to the mean of the parental breeds. This is supported by the Chi-square tests (Table 10), which showed the crossbred means did not consistently differ from those expected f r o m the parents. The distributions of scores within traits deviated f r o m the parental mean more than would be expected by chance in only 24 ( 2 1 % ) of the 114 comparisons. The frequency of abnormalities such as parrot jaw, capped hip, wry tail, bad feet, etc., also was recorded. The incidence was low in all groups, and the occurrences in the crossbreds did not differ from the purebreds. The results show the body characteristics of twoand three-breed crosses at about two and onehalf years of age were generally an average of the purebred p a r e n t breeds, which indicates there is little or no heterosis for most traits which are commonly used to describe dairy type. These preliminary results suggest positive heterosis for traits of economic importance to dairy production in first l a c t a t i o n - - m i l k yield,

777

milk quality, utilization of feed f o r productive purposes, and reproductive efficiency. H o w ever, the heterosis in second and later lactations or total lifetime performance cannot be discerned at this time. I t could be that the crossbred is physiologically more mature by first lactation; thus, less susceptible to the stresses of lactation and is, therefore, in somewhat better position to cope with the hazards of the productive stage of life than the animal which still has demands for development. Such a hypothesis is supported by results from most inbreeding investigations. References

(1) Albrectsen, R. 1957. Type appraisa]--A new look at dairy type. ]{oard's Dairyma~l, 102(3) : 113. (2) Bereskin, B., and R. W. Touchberry. 1966. Lactation productio~x by purebred and crossbred dairy cattle. J. Dairy Sci., 49: 659. (3) Johnson, J. C., Jr., R. D. Johnson, W. R. Harvey, R. E. McDowell, and B. L. Southwell. 1964. Performance of crossbred and purebred dairy cattle. J. Anita. Sei., 23: 850. (4) Kendrick, J. F. 1953. Standardizing Dairy Herd Improvement Association records in proving sires. U.S. Dept. Agr. BDI-Inf162. (5) Lee, D. I-I. K. 1953. Manual of field studies on the heat tolerance of domestic animals. FAO Dev. Paper no. 38. (6) McDaniel, B. T., C. A. Matthews, and N. D. Bayley. 1959. Screening records for inheritance studies. Proc. Southern Reg. Tech. Comm., S-3. (7) MeDaniel, B. T., R. H. Miller, and E. L. Corley. 1965. D H I A factors for projecting incomplete records to 305 days. Dairy Herd Improvement letter. U.S. Dept. Agr. ARS-44-164. (8) McDanlel, B. T., R. H. Miller, E. L. Corley, and R. D. Plowman. 1967. D H I A age adjustment factors for standardizing lactations to a nmture basis. U.S. Dept. Agr. ARS-44-188. (9) :M[orrison, F. B. 1957. Feeds and Feeding. The Morrison Publishing Co., Ithaca, N.Y. (10) Okumu, C, and J. C. Berry. 1966. Studies of milk production in crossbred dairy cattle. E. African Agr. Forestry J., 31: 163. (11) Pearson, L., and R. E. McDowe]l. 1968. Crossbreeding of dairy cattle in temperate zones: A review of recent studies. Anita. Breeding Abstr., 36(1): (In press).

J. DAIRY SCIENCE VOL. 51, NO. 5