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BUL821 Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in South Florida 1 J.R. Crockett and M. Koger2 1. This document is BUL821, one of a series of the Animal Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date March 1982. Reviewed June 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. J.R. Crockett, Associate Professor, Agricultural Research and Education Center, Belle Glade, and M. Koger, Professor, Department of
Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in.... 2 Females used in this study were descendants of Herefords brought onto the reservation from Arizona (San Carlos Apache Reservation) in 1936 and 1938. These cattle underwent natural selection (survival of the fittest) for approximately 25 years. Though Brahman bulls were used for a time on some of the females during the beginning years, Hereford bulls were the predominant herd sires used. Many of the introduced Hereford bulls, however, were under considerable environmental stress and some failed to survive the rigors of the environment. In 1964, a group of approximately 300 females was selected from a total of about 3500 to determine the feasibility of producing high quality range bulls for this particular environment. Selection was based on pregnancy status of the cows and phenotype of their nursing calves. The females were divided into six two-sire herds, which were managed on semi-improved pastures. Registered Hereford bulls were introduced at this time. During subsequent years, intensive selection for reproduction and production was practiced on the progeny of the foundation females with highly selected female progeny being returned to the cow herd and selected bull progeny going to the commercial range herd. Highly selected males were returned to the foundation herd for use as herd sires. By 1970 the entire bull battery consisted of bulls raised within the herd. In 1975 it appeared that the calves from the range herd contained too much British blood and a decision was made to infuse a low level of Brahman breeding into the herd. The Beefmaster and Braford breeds were chosen for this purpose rather than straight Brahman bulls. In 1976 the existing grade Hereford females were divided into three equal 2-sire herds to be mated, respectively, to Beefmaster, Braford or Hereford bulls. The breeding season began March 1 and was 70 days in length. Calves were born in December and January, and weaned the first week of August at an average age of 237 days. Females were bred to calve first at three years of age and all females were palpated in September and culled the first time open. The cattle were maintained on Pangola grass ( Digitaria decumbens ) pastures and received 16% protein cane molasses as a supplement during the winter. Data from the 1976 through 1980 calf crops were analyzed using the least squares technique described by Harvey (3). Data collected included pregnancy rate as determined by palpation, survival from birth to weaning and weaning weight, while unadjusted 205-day weight was calculated. Year, breed of sire, sex of calf, age of dam and breed x sex interaction were the variables used in the model ( Table 1 ). RESULTS AND DISCUSSION Pregnancy rate The effect of year was included in the analyses ( Table 1 ) to increase precision and, as usual in this type of data, was highly significant (P < .0l). During previous years, conception rate for the herd had averaged near 90%. In this study, however, reproduction was more erratic with a high of 91% in 1977 and a low of 79% in 1979 ( Table 2 ). It was concluded that either climatic conditions or management or a combination of the two was the probable cause. The only other factor influencing pregnancy rate was that of age of dam (P<.Ol). As shown in Table 2, three-year-old cows nursing their first calves had a conception rate of 76% as compared 89, 87, and 87% for the first exposure females and the two older cow groups, respectively. This was due primarily to the management of the younger females entering the herd as two-year-olds. They were bred with the cow herd and were given no preferential treatment following their first parturition. This behavior is common in young females in Florida that are not given special attention. Survival rate This response trait showed only age of dam to have a significant effect (P < .05). The youngest cows (three-year-olds) lost a few more calves from birth to weaning. Observations would suggest that difficult birth was not a prime factor. Calves usually were born alive but did not survive. Weaning weight This trait was influenced by year, sex of calf and age of dam (P < .01) and breed of sire (P < .05). As in much other data of this kind, year and age of dam would be expected to have a significant effect. Most research shows that young first calf cows do not perform as well as older cows up to 10 years of age and most data is adjusted for age differences. However, in this study the young
Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in.... 3 (three-year-old) cows were equally as productive as cows in the four-year-old and five-to nine-year old age groups with average calf weanings weights of 219.9 kg (485 pounds), 220.4 kg (486 pounds) and 220.9 kg (487 pounds), respectively (Table 2). Calves weaned from ten-year-old and older cows were significantly lower (P < .0l) at 207.7 kg (458 pounds) than those from younger females. Numbers were small in this group due to the practice of culling cows over ten years of age. One possible explanation for the above average performance of the young cows is probably due to selection on their dam's production record. The most surprising result was the rather small difference between breed of sire groups with 220.4 kg (486 pounds), 216.4 kg (477 pounds) and 214.5 kg (473 pounds) for calves sired by Beefmaster, Hereford and Braford bulls, respectively. More surprising was the observation that adapted grade Hereford calves were comparable to those of the two Brahman-derivative sire breeds. Breed-of-sire differences for estimated 205-day weight were more significant than those for actual weaning weight (P <.05 vs. P < .0 1) as shown in Table 2. This was due to the Beefmaster sired calves averaging five and three days younger in age, respectively, at weaning than the Braford and Hereford sired calves. SUMMARY AND CONCLUSIONS The performance of straightbred grade Hereford calves was compared to that of offspring from comparable dams mated to Beefmaster and Braford sires. Breed of sire significantly affected (P < .05) actual weaning weight and 205-day weight (P < .0l). The five-year average, however, showed a difference in weaning weight of only 5.9 kg (13 pounds) between the heaviest (Beefmaster) and lightest (Braford) groups. Age of dam had a more significant effect on performance traits studied (pregnancy, P < .01; survival, P < .05; weaning weight, P < .0l; and 205-day weight, P < .0l) than did breed of sire. Three-year-olds nursing their first calves were lower in conception than younger and older cows, showed a lower survival rate than calves from older cows. Cows ten years old and older failed to wean as heavy calves as did younger cows. These data indicate that temperate zone breeds, which have become adapted to subtropical conditions through natural selection and a period of intense artificial selection, can be made to perform competitively with breeds adapted to subtropical environments. However, this would involve a long time adjustment. If this particular group of females had not been well adapted it is possible that more observable difference would have been noted in performance. This bulletin contains only data obtained on performance of Hereford dams and their straightbred and crossbred progeny. It appeared that heterosis levels for weaning weights, obtained from mating Beefmaster and Braford bulls to these females, were very low (1.8% and -0.08% for Beefmasterand Braford-sired calves, respectively). Most research data has shown that higher heterosis levels are obtained when cattle of Zebu (Bos indicus ) and British ( Bos taurus ) breeding are intermated than when matings are made between breeds of British breeding (4). The same source presented data indicating that certain levels of Zebu breeding were essential for adaptation to tropic and subtropic environments. In this study the theoretical amount of Zebu breeding contributed from the Beef master and Braford bulls to their progeny was 25% and 18.75%, respectively. As upgrading continues with the Beefmaster (47-50% Zebu) and Braford (37.5% Zebu) it is highly probable that after three or four generations more pronounced differences will appear. LITERATURE CITED 1. Bonsma, J. C. 1973. In Crossbreeding Beef Cattle, Series 2, M. Koger, T. J. Cunha and A. C. Warnick (Eds.) 1973. University of Florida Press, Gainesville. 2. Cunha, T. J., M. Koger and A. C. Warnick (Eds.) 1963. Crossbreeding Beef Cattle. University of Florida Press, Gainesville. 3. Harvey, W. R. 1960. Least-squares Analyses of Data With Unequal Subclass Numbers. U.S.D.A. ARS 20-8.
Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in.... 4 4. Koger, M., T. J. Cunha and A. C. Warnick (Eds.) 1973. Crossbreeding Beef Cattle, Series 2. University of Florida Press, Gainesville. 5. Rouse, J. E. 1969. World Cattle 1. University of Oklahoma Press, Norman.
Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in.... 5 Table 1. Table 1. Probability values from analyses of variance for performance traits. Source df Pregnancy rate Survival rate Weaning weight 205-day weight Years 4 ** NS ** ** Breed of sire 2 NS NS ** Sex of calf 1 --** ** Age of dam 3 ** ** ** Breed x sex 2 --NS NS df for remainder 1457 1065 1019 1019 ** = P<.Ol* = P<.05 NS = nonsignificant.
Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in.... 6 Table 2. Table 2. Least squares means for performance traits. Effect N Pregnancy rate(%) N Survivala rate(%) N Weaning weight(kg)b 205-day weight(kg) Breed of sire Beefmaster 429 84.3 313 95.5 298 220.4 197.3 Braford 439 84.8 329 96.9 319 214.5 191.1 Hereford 599 85.4 433 95.4 415 216.4 190.5 Age of dam 3 years 306 89.0 249 92.6 230 220.0 192.8 4 years 264 76.0 190 96.9 183 220.4 196.9 5-9 years 695 87.4 523 97.5 510 220.9 197.3 10 years and older 202 87.0 113 96.6 109 207.7 183.3 Years 1976 317 84.2 212 98.4 208 207.7 194.1 1977 302 91.0 252 93.2 235 210.0 179.6 1978 308 90.0 235 95.3 225 200.5 177.8 1979 290 79.0 184 96.1 178 233.2 203.7 1980 250 80.4 192 96.5 186 234.1 208.7
Production of Grade Hereford, Beefmaster x Hereford, and Braford x Hereford Calves in.... 7 Table 2. Mean or total 1467 84.8 1075 95.9 1032 217.3 192.8 aDifferences between numbers for pregnancy and survival were due both to open cows being excluded from the latter and to culling low producing and unsound cows that were pregnant.b1 kg = 2.205 pounds.