BREED AND HETEROSIS EFFECTS OF AMERICAN ZEBU CATTLE 1,2

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1 BREED AND HETEROSIS EFFECTS OF AMERICAN EBU CATTLE 1,2 Summary The Brahman (American ebu) has been evaluated in numerous crossbreeding studies throughout the Southern United States. Brahman females producing straightbred calves have usually been found to have a lower calving percentage, calf survival rate and weaning rate than other contemporary straightbreds, although they have been reported to be superior or competitive in some studies. Birth weights of Brahman calves have been larger than those of Angus, smaller than Charolais and comparable to those of Herefords. Brahman steers generally have had lower postweaning daily gains, lower carcass grades, less backfat and higher Warner-Bratzler shear values than other contemporary straightbreds. Heterosis estimates for reproduction have been small and variable in producing F 1 calves, but larger and positive for reproductive traits of F 1 cows. Birth and weaning weight heterosis estimates averaged 3.3 and 21.7 kg for FI calves and 1.9 and 31.1 kg for calves of F 1 cows. Small and variable heterosis estimates have been found for all carcass traits. (Key Words: American ebu, Breed Effects, Heterosis.) Introduction The Brahman (American ebu) has made a significant contribution to the cattle industry in the South and Southeastern United States. The ability of the Brahman and its crosses to adapt to the hot and humid conditions of the Gulf Coast region and generally to tolerate cattle pests that were troublesome to other l Presented at a symposium on "The Role of ebu Cattle in Efficient Beef Production" at the Annu. Meet. of the Southern Sec. of the ASAS, Feb. 5, 1979, in New Orleans, LA. 2Published with approval of the Director of D. E. Franke 3 Louisiana State University, Baton Rouge 783 Breeding Value the Louisiana Agr. Exp. Sta. 3 Anim. Sci. Dept. Reproductive 126 breeds led to interest in its exploitation. The early work of Lush et al. (193) and Black et al. (1934) provided evidence that Brahman influence was desirable for growth and carcass characteristics in yearling cattle. Work with Brahman-Angus crosses at the Iberia Station in Louisiana laid the groundwork for synthesis of the breed now known as the Brangus (Rhoad and Black, 1943; Baker and Black, 195). Since the early 195's, many Land-Grant Agricultural Experiment Stations have included the Brahman in crossbreeding studies to further evaluate its place in the industry. Much of the research was involved in the Southern Regional Project, S-IO. Reviews of research involving the Brahman have been made by Kincaid (1962), Mason (1966), Temple (1966), Warwick (1968) and Cundiff (197). Symposia designed to bring together information on crossbreeding, including the Brahman have been sponsored by the University of Florida, with proceedings published by Cunha et al. (1963) and Koger et al. (1973). The purpose of this paper was to review the research on utilization of the Brahman, with particular attention to straightbred and crossbred performance. The optimum usage of the Brahman or any breed will depend on its breeding value and contribution to heterosis for traits of economic importance. The American Brahman is the result of upgrading by the breeding of various strains of ebu males to native or domestic cows typical of the Gulf Coast region during the 192's, 193's and the 194's (Sanders, 198). Few pure strains of ebu cattle exist today in the United States. Consequently, most research results are based on use of the Brahman. Traits. Calving rate, calf JOURNAL OF ANIMAL SCIENCE, Vol. 5, No. 6, 198

2 BRAHMAN cattle PERFORMANCE 127 survival and weaning rate of Brahman and other contemporary breeds have been reported by researchers in Florida, Louisiana and Texas (table 1). Brahman cows were observed to have a lower reproductive rate than Angus and Hereford cows in some studies (Cartwright et al, 1964; Crockett et al., 1978a) but were superior to Shorthorn cows (Peacock et al., 1971) and competitive in others. A summary of reproductive rates of straightbred cows in the Southern Regional Project S-1, indicated that Brahman and Brangus cows that were dry during the breeding season had a higher calving rate than lactating Brahman or Brangus cows (Temple, 1966). Similar results for Brahman cows were reported by Peacock et al. (1976). Rebreeding rates of lacating Angus and Hereford cows in the Southern Regional Project, S-IO, were higher than those of dry Angus and Hereford cows (Temple, 1966). Various aspects of reproductive behavior in Brahman females were reported by Plasse et al. (1968a,b,c; 197). Age at first corpus luteum was 19.4 months, and ovarian function decreased markedly during the winter season. Gestation length was observed to be days, with male calves carried 1.9 days longer than females. Preweaning Traits. Birth weights, weaning weights and weaning scores for Brahman and contemporary straightbred calves are presented in table 2. Ellis et al. (1965) reported that Brahman calves were 3.9 kg smaller at birth than Herefords, but Turner and McDonald (1969) and Crockett et al (1978b) found birth weights of Brahman calves to be similar to those of Herefords and heavier than those of Angus calves. Turner and McDonald (1969) found that Brahman calves had preweaning daily gains similar to those of Hereford and Brangus calves and higher than those of Angus calves. Differences in weaning weights between Brahman and other breeds have varied considerably from station to station. Brahman calves weighed less at weaning than did Herefords in one Louisiana study (Damon et al., 1959a) but were similar in weight in all others. Brahman calves were heavier at weaning than Shorthorn calves (Koger et al., 1975) but were smaller than Charolais calves (Peacock et al., 1978). Damon et al. (1961) reported that the maternal ability of the Brahman was superior to that of the Hereford but inferior to that of the Angus. Deese and Koger (1965) observed a TABLE I. REPRODUCTIVE PERFORMANCE OF BRAHMAN AND CONTEMPORARY STRAIGHTBREDS No. of Calving Calf Weaning Adapted from Breed matings rate survival rate Cartwright et al., 1964 B H Turner et al., 1968 B A Ba H Peacock et al., 1971 B 12 b S I Peacock et al., 1977 B A C ,1 77,9 Crockett et. al., 1978a B 27 b A H abreed code: A = Angus, B = Brahman, C = Charolais, Ba = Brangus, D = Devon, S = Shorthorn. bapproximate. (%).

3 128 FRANKE TABLE 2. PREWEANING TRAITS OF BRAHMAN AND CONTEMPORARY STRAIGHTBREDS No. of Birth Weaning Weaning Adapted from Breed a records wt wt score b Damon et al., 1959a B I 1.3 A H Ba C.artwright et al., 1964 B H Kidder et al., 1964 B A D Koger et al., 1975 B S Turner and McDonald, 1969 B A Ba H Peacock et al., 1978 B A C Crockett et al., 1978b B A H abreed code: see table 1. bbased on 17-point scale: 9 = low good, 1 = average good and high good. r significant maternal component for preweaning growth in Brahman and crossbred cows. Postweaning Performance. Average daily gain and carcass characteristics of Brahman and other straightbred steers are summarized in table 3. Data from different trials may not be comparable because of differences in postweaning management procedures. With the exception of data reported by Peacock et al. (1973), results show that Brahman steers have tended to gain less per day than contemporary steers of other breed groups over a wide range of postweaning management systems. Quality grades of Brahman carcasses have ranged from Standard to Middle Good and have been similar to those of Charolais but generally lower than those of Angus and Hereford carcasses. Ribeye areas generally have been comparable to those of Angus and Hereford steers but smaller than those of Charolais. Brahman, Brangus and Charolais have been found to be similar in fat thickness and yield grade. Warner-Bratzler shear force values consistently have been higher for the Brahman than for other breeds. Carpenter et al. (1961) reported that Brahman steers had a higher percentage of sirloin and combined cuts of round, rib and full loin than Brahman-Shorthorn cross steers, but graded lower, had less fat in the carcass and were less tender as judged by a taste panel and Warner-Bratzler shear values. Similar results on tenderness were reported by Luckett et al. (1975). Heterosis Reproductive Traits. The mating of Brahman and Hereford (Cartwright et al., 1964) or Shorthorn (Peacock et al., 1971) to produce F 1 calves resulted in no increase in calving rate; however, a 15.% advantage in survival rate of Brahman-Hereford calves over straightbreds was

4 BRAHMAN CATTLE PERFORMANCE 129 =. U = c~ n~ U t~ r~ E e~ z,4 M o ~ Ox v o e4" -~, ~ E i.~ s..

5 121 FRANKE observed. There was a 3.8% advantage for calf survival in Brahman-Charolais cross calves but a negative heterosis effect of -1.2% for calf survival in Brahman-Angus cross calves (Peacock et al., 1977). The heterosis level for weaning rate of F 1 Brahman-Hereford cross calves was.3% (Cartwright et al., 1964) and -6.4 and 1.6% for Angus-Brahman and Brahman-Charolais cross calves, respectively (Peacock et al., 1977). Kidder et al. (1964) and Peacock et al. (1971) reported small positive heterosis effects for weaning rates of F1 Brahman-British calves. First-cross Brahman-British cows showed positive levels of heterosis for reproductive traits (table 4). Heterosis estimates for calving rate have ranged from 4.4% for Brahman- Hereford cows (Crockett et al., 1978a) to 18.8% for Brahman-Hereford cows (Turner et al., 1968). Weaning rate heterosis levels have ranged from 7.1% for Brahman-Angus cows to 21.2% for Brahman-Hereford cows. Preweaning Traits. Birth weights of F 1 Brahman-Hereford calves and Brahman-sired calves were 3.3 and 3.5 kg higher, respectively, than birth weights of contemporary straightbreds (Cartwright et al., 1964; Turner and McDonald, 1969). Weaning weight advantages of F l Brahman- British calves over parental averages have ranged from 7. kg for Brahman-Brangus calves (Da- monet al., 1959a) to 26. kg for Brahman- Hereford calves (Cartwright et al., 1964). Weaning weight advantages of other F z Brahman cross calves over parental averages are presented in table 5. Heterosis estimates for calves from F 1 Brahman cross cows are shown in table 6. Heterosis for weaning weight has ranged from 16.5 kg for calves from F 1 Brahman-Brangus cows (Babcock, 1978) to 43.5 kg for calves from F1 Brahman-Angus cows (Kidder et al., 1964). Heterosis estimates for weaning weights of F 1 Brahman-Brangus cows have tended to be smaller than those of contemporary Brahman- British crosses. Advantages of backcross calves over straightbred parental averages have ranged from 1.6 to 3.2 kg for average birth weight (Cartwright et al., 1964; Crockett et al., 1978b) and from 27.2 to 43.5 kg for average weaning weight (Kidder et al., 1964). Babcock (1978) reported that backcross and three-breed cross calves from F 1 Brahman cross cows were.8 to 2.8 kg heavier at birth than straightbred and F 1 calves from parental straightbred cows. Differences among reciprocal F 1 Brahman cross cows were found to be small and nonsignificant but favored first cross cows out of Brahman and Brangus dams over those from British dams (Turner, 1969). Evidence of maternal heterosis in Fg Brahman-Hereford cows was presented by Cart- TABLE 4. HETEROSIS ESTIMATES FOR REPRODUCTIVE TRAITS OF F 1 BRAHMAN CROSS COWS a Breed of Calving Calf Weaning Adapted from cow b rate survival rate Turner et al., 1968 B A B Ba B X H Cartwright et al., 1964 B H Peacocketal., 1971 B S Crockett et al., 1978a B A B H Weighted avg c a.. Expressed as a deviation from the purebred average. bbreed code: see table 1. Breed of cow includes reciprocals, except for Crockett et al. (1978a), where the first breed code represents breed of sire. CEach estimate weighted with ratio n c ns/n c + ns, where n c and n s are numbers of crossbreds and straightbreds, respectively. (%)

6 BRAHMAN CATTLE PERFORMANCE 1211 TABLE 5. HETEROSIS ESTIMATES OF PREWEANING TRAITS OF F 1 BRAHMAN CROSS CALVES a Breed of Birth Weaning Weaning Adapted from calf b wt wt score (kg) Cartwright et al., 1964 Peacock et al., 1978 Koger et al., 1975 Damon et al., 1961 Turner and McDonald, 1969 Weighted avg c BXH BXA B BXS BXA B Ba BXH B (A, Ba, H) L aexpressed as a deviation from the purebred average9 bbreed code: see table 1. Breed of calf includes reciprocals, except for Turner and McDonald (1969), where first breed code represents breed of sire. CEach estimate weighted with ratio n c ns/n c + n s, where n c and n s are numbers of crossbreds and straightbreds, respectively. TABLE 6. HETEROSIS ESTIMATES FOR PREWEANING TRAITS OF CALVES FROM F 1 BRAHMAN CROSS COWS a Breed Birth Weaning Adapted from of cow b wt wt Cartwright et al., 1964 Kidder et al., 1964 Turner and McDonald, 1969 Koger et al., 1975 Crockett et al., 1978b Babcock, 1978 Weighted avg c -- (kg)- B H B X D B X A B X A B Ba B H... 34,4 B X S B X A B X H B X A B X Ba B H aexpressed as a deviation from the purebred average. bbreed code: see table 1. Breed of cow includes reciprocals, except for Crockett et al. (1978b), where first breed code represents breed of sire. CEaeh estimate weighted with ratio n c ns/n c + ns, where n e and n s are numbers of crossbreds and straightbreds, respectively.

7 1212 FRANKE p, e~ u r, e~ z e~ 9 z~ I" I" I" ~ I" I' I m e- ra E~ v,d V" E -n [- i. wright et al. (1964). Backcross calves from F 1 Brahman-Hereford sires and straightbred Brahman and Hereford cows were 9.3% heavier at weaning than were straightbred calves, while backcross calves out of F l Brahman-Hereford cows weighed 18.8% more than straightbred calves. The difference was attributed to maternal heterosis of the F 1 cow. McDonald and Turner (1972) used crosses of Angus, Brahman, Brangus, Hereford and Charolais breeds to evaluate maternal heterosis. They reported that Brahman-Hereford cows had the largest maternal heterosis component of any of the crosses, followed closely by Brahman-Angus and Brangus-Hereford cows. Maternal heterosis in Brangus-Angus and Hereford-Angus cows was small and nonsignificant. Further evidence of the existence, and the importance, of maternal heterosis was presented by Koger et al. (1975) for Brahman-Shorthorn cross cows. Postweaning Traits. Data on F1 Brahman cross and contemporary straightbred steers that document heterosis effects for postweaning traits are limited. Work at the Louisiana Station (Damon et al., 196; Turner, 1973) indicated small and generally nonsignificant differences between crossbreds and parental straightbreds (table 7). Usually, however, crossbreds have been reported to grow slightly faster, grade slightly higher, have more fat cover and be more tender than parental averages. Carpenter (1973), in discussing carcasses of crossbreds, indicated that heterosis was limited almost entirely to traits associated with carcass weight or growth. Brahman-British crosses tended to fall between British and Brahman, except for the growth-related traits. Work with variable percentages of Brahman-British steers has generally indicated trends similar to those among weighted straightbred averages (Carpenter et al, 1961 ; Turner, 1973 ; Franke et al., 1977). X X X X X X..1 E o ~ o ~ m ox v g Literature Cited Babcock, Deborah S Probable producing ability of straightbred and crossbred beef cows. M.S. Thesis. Louisiana State Univ., Baton Rouge. ~. Baker, A. L. and W. H. Black Crossbred types u~ of beef cattle for the Gulf Coast region. USDA e~ Circ9 844, Black, W. H., A. T. Temple and J. C. Lush Beef production and quality as influenced by crossing o Brahman with Hereford and Shorthorn cattle.,v USDA Tech. Bull Carpenter, J. W., A.. Palmer, W. G. Kirk, F. M. Peacock and M. Koger Slaughter and

8 BRAHMAN CATTLE PERFORMANCE 1213 carcass characteristics of Brahman and Brahman- Shorthorn crossbred steers. J. Anita. Sci. 2:336. Carpenter,. L Effects of crossbreeding on carcass characteristcs. In M. Koger, T. J. Cunha and A. C. Warnick (Ed.) Crossbreeding Beef Cattle. Series 2. University of Florida Press, Gainesville. Cartwright, T. C., G. F. Ellis, Jr., W. E. Kruse and E. K. Crouch Hybrid vigor in Brahman- Hereford crosses. Texas Agr. Exp. Sta. Tech. Monogr. 1. Crockett, J. R, Finishing calves from a crisscross breeding system. In M. Koger, T. J. Cunha and A. C. Warnick (Ed.) Crossbreeding Beef Cattle. Series 2. University of Florida Press, Gainesville. Crockett, J. R., M. Koger and D. E. Franke. 1978a. Rotational crossbreeding of beef cattle: Reproduction by generation. J. Anim. Sci. 46:1163. Crockett, J. R., M. Koger and D. E. Franke. 1978b. Rotational crossbreeding of beef cattle: Preweaning traits by generation. J. Anim. Sci. 46:117. Cundiff, L. V Experimental results on crossbreeding cattle for beef production. J. Anim. Sci. 3:694. Cunha, Tony J., M. Koger and A. C. Warniek (Ed.) Crossbreeding Beef Cattle. University of Florida Press, Gainesville. Damon, R. A., Jr., R. M. Crown, C. B. Singletary and S. E. McCraine Carcass characteristics of purebred and crossbred beef steers in the Gulf Coast region. J. Anim. Sci. 19:82. Damon, R. A., Jr., W. R. Harvey, C. B. Singletary, S. E. McCraine and R. M. Crown Genetic analysis of crossbreeding beef cattle. J. Anita. Sci. 2:849. Damon, R. A., Jr., S. E. McCraine, R. M. Crown and C. B. Singletary. 1959a. Performance of crossbred beef cattle in the Gulf Coast region. J. Anim. Sci. 18:437. Damon, R. A., S. E. McCraine, R. M. Crown and C. B. Singletary. 1959b. Gains and grades of beef steers in the Gulf Coast region. J. Anita. Sci. 18:113. Deese, D. E. and M. Koger Maternal effects on preweaning growth rate in cattle. J. Anim. Sci. 26:25. Ellis, G. F., Jr., T. C. Cartwrigbt and W. E. Kruse Heterosis for birth weight in Brahman- Hereford crosses. J. Anita. Sci. 24:93. Franke, D. E., T. D. Bidner and M. S. Taylor Comparing growth and carcass characteristics of beef cattle. Louisiana Agr. 21:8. Kidder, R. W., M. Koger, J. H. Meade and J. R. Crockett Systems of crossbreeding for beef production in Florida. Florida Agr. Exp. Sta. Bull Kincaid, C. M, Breed crosses with beef cattle in the South. USDA Southern Coop. Ser. Bull. 81. Koger, M., Tony J. Cunha and A. C. Warnick (Ed.) Crossbreeding Beef Cattle. Series 2. University of Florida Press, Gainesville. Koger, M., F. M. Peacock, W. G. Kirk and J. R. Crockett Heterosis effects on weaning performance of Brahman-Shorthorn calves. J. Anim. Sci. 4:826. Luckett, R. L., T. D. Bidner, E. A. lcaza and J. W. Turner Tenderness studies in straightbred and crossbred steers. J. Anim. Sci. 4:468. Lush, Jay L., J. M. Jones, W. H. Dameron and D. C. Carpenter Normal growth of range cattle. Texas Agr. Exp. Sta. Bull. 49. 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Anita. Sci. 47:366. Peacock, F. M., M. Koger, W. G. Kirk, E. M. Hodges and A. C. Warnick Reproduction in Brahman, Shorthorn and crossbred cows on different pasture programs. J. Anita. Sci. 33:458. Plasse, D., A. C. Warnick and M. Koger. 1968a. Reproductive behavior of Bos indicus females in a subtropical environment. I. Puberty and ovulation frequency in Brahman and Brahman-British heifers. J. Anim. Sci. 27:94. Plasse, D., A. C. Warnick and M. Koger. 1968b. Reproductive behavior of Bos indicus females in a subtropical environment. II. Gestation length in Brahman cattle. J. Anim. Sci. 27:11. Plasse, D., A. C. Warnick and M. Koger. 1968c. Reproductive behavior of Bos indicus females in a subtropical environment. IlL Calving intervals, intervals from first exposure to conception and intervals from parturition to conception. J. Anim. Sci. 27:15. Plasse, D., A. C. Warnick and M. Koger Reproductive behavior of Bos indicus females in a subtropical environment. IV. Length of estrous cycle, duration of estrus, time of ovulation, fertilization and embryo survival in grade Brahman heifers. J. Anita. Sci. 3:63. Rhoad, A. O. and W. H. Black Hybrid beef cattle for subtropical climates. USDA Circ Sanders, J. O History and development of ebu cattle in the U.S.J. Anim. Sci. 5:1188. Temple, R. S Reproduction of beef cattle in the South. USDA Southern Coop. Ser. Bull Turner, J. W Preweaning production differences among reciprocal crossbred beef cows. J. Anim. Sci. 29:857. Turner, J. W Brahman European crosses versus other breeds in feedlot. In M. Koger, T. J.

9 1214 FRANKE Cunha and A. C. Warnick (Ed.) Crossbreeding Beef Cattle. Series 2. University of Florida Press, Gainesville. Turner, J. W. (Bill), B. R. Farthing and G. L. Robertson Heterosis in reproductive performance of beef cows. J. Anim. Sci. 27:336. Turner, J. W. and R. P. McDonald Mating type comparisons among crossbred beef cattle for preweaning traits. J. Anim. Sci. 29:389. Warnick, E. J Crossbreeding and linebreeding beef cattle experimental results. World Rev. Anita. Prod. IV (19-2):37.