BEEF BEEF AND DAIRY BEEF FEMALES MATED TO ANGUS AND CHAROLAIS SIRES. II. CALF GROWTH, WEANING RATE AND COW PRODUCTIVITY 1'2

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1 BEEF BEEF AND DAIRY BEEF FEMALES MATED TO ANGUS AND CHAROLAIS SIRES. II. CALF GROWTH, WEANING RATE AND COW PRODUCTIVITY 1'2 L. A. Nelson, G. D. Beavers and T. S. Stewart Purdue University, West Lafayette, IN Summary Preweaning growth of 814 progeny was studied, and weaning rate and kilograms of calf weaned/cow exposed were determined for 310, 2- to 7-yr-old Angus x Hereford (AH), Charolais Hereford (CH), straightbred Hereford (HH) and Brown Swiss Hereford (SH) cows mated to Angus and Charolais bulls. Charolais-sired calves grew more rapidly (P.01) than Angussired calves and were heavier (P.01) at 130 and 210 d of age. Progeny of SH females grew faster (P.05) and were the heaviest at 130 (164 kg) and 210 (231 kg) d, whereas calves from HH dams grew the slowest and weighed the least (P.05) at 130 (126 kg) and 210 (180 kg) d of age. Progeny from AH and CH dams had similar 130-d weights (CW130) and made similar daily gains from birth to 130 d of age (ADG1). Calves from CH females gained faster (P.05) from 130 to 210 d (ADG2) and had higher (P.05) 210-d weights (CW210) than did calves from AH dams. ADG1 and ADG2 of male calves were.043 and.072 kg/d greater, respectively (P.01) than those of heifer calves. Age of dam influenced (P.01) calf preweaning gains and weights. Calves from 4- to 7-yr-old cows had greater (P.05) ADG1 and ADG2 and higher (P.05) CW130 and CW210 than progeny of younger dams. Progeny of 2-yr-old cows grew more slowly (P.05), and were last (P.05) in all traits (ADG1, ADG2, CW130 and CW210), whereas progeny of 3-yr-old cows 1 Journal Paper No. 8204, Purdue Univ. Agr. Exp. Sta. A contribution from the Dept. of Anita. Sci. 2The authors express appreciation to David A. Huber and personnel at the Miller-Purdue Agr. Center for management of cattle and assistance in data collection. This research was supported in part by a cooperative agreement with the American-International Charolais Association, Houston, TX were intermediate to those of 2 and 4- to 7- yr-old females. Cow breed type influenced (P.01) weaning rate (WR) and kilograms of calf weaned/cow exposed. SH females had the highest WR (83.4%), AH and CH were intermediate at 76.8 and 77.7%, respectively, and HH dams had the lowest (P.05) WR, 66.4 calves/100 cows exposed. SH cows weaned 34.6 kg more (P.05) calf/cow exposed than AH and CH dams. HH dams were least productive (P.05), weaning kg calf/cow exposed. Dairy beef dams (SH) weaned 47.6 kg more (P.01) calf/cow exposed than the average of beef beef dams (AH, CH, HH). Dairy beef females had the highest WR and weaned the heaviest calves. (Key Words: Dairy Beef, Breed Types, Calf Growth, Weaning Rate, Cow Productivity.) I ntroduction Crossbred cows have been shown to be more productive than purebred cows (Cundiff et al., 1974a). The success or failure of a crossbreeding system depends mainly on the characteristics of the breeds selected and the specific combining ability of those breeds. Because of higher milk production of dairy x beef crossbred females (Rutledge et al., 1971) they generally wean heavier calves than do beef females. However, little is known about the reproductive performance of dairy beef females. Research documenting the effectiveness of crossbreeding as a management tool for increasing productivity of beef herds has been summarized by Gaines et al. (1966) and Pahnish et al. (1969). To determine means of maximizing production efficiency, different breed types and alternative mating systems need to be evaluated under various management and environmental conditions. The objective of this study was to compare JOURNAL OF ANIMAL SCIENCE, Vol. 54, No. 6, 1982

2 PRODUCTI VITY OF DIFFERENT BREED TYPE COWS 1151 calf growth and productivity of dams of four different breed types mated to Angus and Charolais sires. Materials and Methods Data included weights and gains of 814 calves produced by the mating of Angus and Charolais bulls to Angus Hereford F1 (AH), Charolais x Hereford F 1 (CH), Hereford x Hereford (HH) or Brown Swiss x Hereford F 1 (SH) females. Lifetime performance of each of 310 females was also summarized in terms of weaning rate (WR) and kilograms of calf weaned per exposure. General herd management practices were described by Nelson and Beavers (1982). This study was based upon data from eight mating systems classified by breed type of calf as: two F 1 (A x HH and C x HH), two backcross (A x AH and C CH) and four, threebreed cross (A x CH, A x SH, C AH and C x SH) mating systems. Comparisons of crossbred vs straightbred cows involved a single straightbred (HH) as compared to crosses of Hereford with three other breeds, resulting in AH, CH and SH F 1 cows. Because of the design, it was not possible to determine reciprocal differences among breed types or to estimate heterosis. All mating systems were subjected to the same management system except that 2-yr-olds were fed and housed separately from older cows from about mid November through their first parturition until late April. Cows that failed to have a live calf when entering the breeding season generally were culled. Also, yearling heifers and cows that were found to be nonpregnant in the fall at weaning time were removed from the herd. Thus, strict culling for infertility in this herd would have had an impact upon conception rate, weaning rate and weight of calf weaned/cow exposed over the 6-yr study. Consequently, fertility and productivity characters in our study may be different characters than in a study where nonpregnant cows were allowed to remain in the herd over years. WR was defined as the number of offspring weaned divided by the number of years the female was exposed. The weaning weight of each calf was adjusted to sire breed and calf sex mid- TABLE 1. MEANS SQUARES FOR PREWEANING GROWTH TRAITSa, b Source DF ADG1 CW130 ADG2 CW210 Sire breed (B) 1.18"* 11,752"*.52"* 27,967** Dam breed (D) "* 40,713"*.96** 76,120"* Sex of calf (S) 1.27** 7,335**.76** 23,118"* Calf birth year (Y) 5.60** 12,545 **.40" * 22,559 ** Age of dam (A) 3.49** 5,632**.14"* 9,592** B X D 3.04** 762**.01 1,151" B X S D X S 3.04* 943*.01 1,131 D X A * 552 S X Y ** 850 Y X A 9.03** 927**.02 1,556"* b I (calf birth date) ,521"*.21"* 76,335** b 2 (dam's weight) c 1 3,538** 5,160"* b 3 (dam's weight) " 3,096* * b 4 (dam's weight change) c 1.11 **.36 ** bs (dam's weight change) ** Remainder aadg1 = average daily gain from birth to 130 d; ADG2 = average daily gain from 130 to 210 d; CW130 = calf weight at 130 d; CW210 = calf weight at 210 d. bno difference in levels of significance of-main effects, interactions or calf birth date (b I ) was observed between models that included b 2 and b 3 or b a and b s as covariates and those that did not. CThe test of significance of the partial regression for the highest degree fitted is the only useful test with nonorthogonal polynomials. *P.05. **P.01.

3 1152 NELSON ET AL. point, with the negative of least-squares constants used as additive adjustment factors. No adjustment was made for calf age because the breeding season began at about the same date each year. Kilograms of calf weaned per exposure was equal to the average adjusted weaning weight of all offspring of a given cow x weaning rate for that female. Least-squares, fixed-model procedures (Harvey, 1977) were used for all analyses of preweaning growth traits. The model included effects of breed of sire and dam, calf sex, calf birth year and age of dam. Preliminary analyses included all two-way interactions, but only those approaching significance (P.20) for at least one trait were retained in the final models (table 1). The only first-order interaction included (table 1) that contained empty cells was calf birth year x age of dam, where 75% of the cells were filled. Calf birth year and age of dam were somewhat correlated since all females that calved in 1972 were 2-yr-olds. However, 2-yr-old cows calved each year of the 6-yr study. Calf birth date was included as a covariate in all analyses of calf weights or gains. In addition, all calf growth traits were analyzed with and without dam's weight or weight change as a covariate in the model to determine breed differences beyond effects of cow weight or weight change differences. For analysis of CWl30 and CW210 the corresponding dam's weight was used as the covariate. For analyses of ADG1 and ADG2, the covariate used was the dam's weight change during the corresponding period of calf gain. The least-squares model for WR and kilograms of calf weaned/cow exposed included effects of breed of cow, year that she entered the herd and the two-way interaction. The Newman Keul's sequential range test was used to determine significant differences of paired comparisons among least-squares means. Linear contrasts were calculated to estimate differences among the biological breed types represented in this study. Those contrasts were F1 vs HH and dairy x beef (SH) vs beef x beef (AH, CH, HH). Results and Discussion Mean squares for calf growth traits are presented in table 1. Least-squares means and standard errors are presented in tables 2, 3 and 4. Mean squares and least-squares means for cow productivity characters are given in tables 5 and 6, respectively. Calf Growth. Dam's breed, age and weight or weight change influenced (P.05) all traits. Sire breed, sex of calf and year also affected (P.01) all preweaning traits. Birth date of calf affected (P.01) CW130, ADG2 and CW210. There were no differences in the level of significance of main effects or interactions indicated by models that included, or excluded, dam's weight or weight change as covariates. Minima] differences were observed between least-squares means resulting from the analysis of either adjusted or nonadjusted data when the model included, or excluded, the effects of dam's weight or weight change. Charolais-sired calves gained.04 kg/d more (P.01) from birth to 130 d (ADG1) and were heavier (P.01) at 130 d (CW130) than progeny of Angus sires (table 2). Our results are in agreement with those of Pahnish et al. (1969) and Smith et al. (1976). C-sired calves also gained more rapidly (P.01) from 130 to 210 d of age (ADG2) and were nearly 14 kg heavier at weaning (CW210) than A-sired calves. Knapp et al. (1980) reported a 14.1-kg difference in 205-d weight between C- and A-sired calves out of Brown Swiss dams. Other researchers (Long and Gregory, 1974; Smith et al., 1976) have also reported increases in calf weaning weight and average daily gain from the use of larger, later-maturing sire breed types. Breed type of dam influenced (P.01) ADG1, CW130, ADG2 and CW210 (table 2). Similar results were reported by Long and Gregory (1974) and Belcher and Frahm (1979). Calves from SH dams gained faster (P.05) and had higher (P.05) CW130 and CW210 than calves of all other breed types, whereas calves of HH females had the lowest (P.05) ADG1, CW130, ADG2 and CW210. Calves of AH and CH cows were intermediate in all traits. Pahnish et al. (1969), Holloway et al. (1975) and Belcher and Frahm (1979) obtained increased calf gains, calf weights and total milk yield by incorporating genes from dairy breeds into females managed as beef cows. In this study, calves from SH females gained.17 kg/d faster (P.01) and were 26.5 kg heavier (P.01) at 130 d than calves from beef females (AH, CH, HH). Calves from SH dams weighed kg at weaning, and were followed by CH and AH progeny, and kg, respectively. A difference existed (P.05) between AH and CH females in both ADG2 and CW210 (table 2); whereas Notter et al. (1978) reported that

4 PRODUCTIVITY OF DI FFERENT BREED TYPE COWS 1153 TABLE 2. LEAST-SQUARES MEANS SE FOR CALF DALLY GAINS AND WEIGHTS (KILOGRAMS) a Main effect No. calves ADG1 CW130 ADG2 CW Sire breed ** ** ** ** Angus Charolais Dam breed b * * * * ** * * HH c c.686 "2.010 c c AH d d d d CH d d e e SH e e.860 f f Sex of calf ** ** ** ** Male Female Age of dam, yr ** ** ** ** c c c c d d d d e e e e 5 to e e e e Partial regression: Date of birth linear (X 102 ) ** ** ** Dam's weight linear(x 103)g "* ** quadratic (X 103) " -.43 i.16"* Dam's weight change linear (X 103)g "* i.231"* quadratic (X 103 ) ** aadg1 = average daily gain from birth to 130 d; ADG2 -- average daily gain from 130 to 210 d; CW130 = calf weight at 130 d; CW210 = calf weight at 210 d. ba = Angus, C = Charolais, H = Hereford, S = Brown Swiss. c'd'e'fwithin a main effect class for each trait, means with unlike superscripts differ (P.05) by Newman- Keuls sequential range test. gthe test of sigalificance of the partial regression for the highest degree fitted is the only useful test with nonorthogonal polynomials. *P.05. **P.01. TABLE 3. LEAST-SQUARES MEANS (KILOGRAMS) FOR ADG1 AND CW130 BY SEX AND BREED OF DAM a ADG1 CW130 Dam breed b Male calves Female calves Male calves Female calves HH c c c c AH e d e d CH e d e d SH.97.01g f sg f aadg1 -- average daily gain from birth to 130 d; CW130 = calf weight at 130 d. ba = Angus, C = Charolais, H = Hereford, S = Brown Swiss. c'd'e'f'gmeans for each trait with unlike superscripts differ (P.05) by Newman-Keuls sequential range test.

5 1154 NELSON ET AL. TABLE 4. LEAST-SQUARES MEANS (KILOGRAMS) FOR ADG1, CWI30 AND CW210 BY BREED OF SIRE AND DAM a Breed b ADG1 CW130 CW210 Dam Sire: A C A C A C HH c c c d c d AH d f e g d f CH e ef f g e f SH g.95.01g h x 1.9 i g h aadg1 = average daily gain from birth to 130 d; CW130 = calf weight at 130 d; CW210 = calf weight at 210 d. ba = Angus, C = Charolais, H = Hereford, S = Brown Swiss. c'd'e'f'g'h'imeans for each trait with unlike superscripts differ (P.05) by Newman-Keuls sequential range test. progeny of Charolais-cross cows did not exceed those of AH dams in either average daily gain or 210-d weight. Belcher and Frahm (1979) reported average daily gains of.78 and.68 kg for progeny of SH and AH females, respectively. McGinty and Frerichs (1971) found a 25 kg/calf advantage in weaning weight for calves from SH females compared with those from HH dams, while Kropp et al. (1973) reported that calves from Hereford x Holstein cows were nearly 25 kg heavier than those from Hereford dams. In our study, progeny of dairy x beef (SH) dams gained faster and weighed 35.5 kg more (P.01) at weaning (CW210) than did offspring of beef beef (AH, CH, HH) dams. Knapp et al. (1980) and Frahm etal. (1981) also reported greater preweaning daily gain and higher 205- d weights for calves from Brown Swiss-cross dams than for those from beef beef dams. In a study by Patterson et al. (1974), dairy beef (SH and Holstein x Hereford) dams weaned heavier (P.01) calves than did Charolais Hereford or grade Hereford dams. In contrast, Parker and Van Keuren (1979) found no difference in 205-d weights of progeny from Brown Swiss Angus cows, Jersey x Angus cows or Charolais Angus reciprocal crosses that calved in the fall. Calves nursing F 1 females (AH, CH, SH) gained.12 kg/d more (P.01) during ADG2 and weighed 32.6 kg more (P.01) at 210 d than did calves from HH dams. These values are somewhat higher than those found by Cundiff et al. (1974b) and Gaines et al. (1978), who reported an 8.5-kg advantage in calf weaning weight for crossbred females over straightbreds. Neither study utilized dams with dairy breeding, but did include Angus and Shorthorn cows. In our study, only HH straightbreds were included and not AA, CC or SS straightbreds. Sex of calf influenced (P.O1) ADG1, CW130, ADG2 and CW210. Male calves gained faster than heifer calves, resulting in a 7-kg advantage in CW130. Findings reported by Marlowe and Gaines (1958) are in agreement. Steer calves also gained.07 kg/d more from 130 d to weaning, giving them a 12.5-kg advantage (P.01) in CW210 over heifer calves. Marshall et al. (1976) and Gregory et al. (1978) reported 19-and 14-kg weaning weight advantages, respectively, for male calves. Age-of-dam effects were a source of variation (P.01) in calf gains and weights. It has been shown (Marlowe and Gaines, 1958; Gregory et al., 1979) that dam's age at calving has an important influence on calf gain. Progeny of 4- to 7-yr-old dams gained most rapidly (P.05) and had the highest (P.05) ADG1, CW130, ADG2 and CW210. Performance of calves from 3-yr-old dams was intermediate and superior (P.05) to that of progeny from 2-yr-olds. Melton et al. (1967) and Holloway et al. (1975) found that as cows mature there is a trend toward higher milk yield, generally resulting in increased calf weight. Linear regression on calf birth date was nonsignificant for ADG1; however, it was an important (P.01) contribution to variation in CW130, ADG2 and CW210 (table I). Each 1-d increase in calf age resulted in an increase of.83 kg in CW130. Each lo-d increase in age resulted in a.012-kg/d increase in ADG2 and a 7.5-kg advantage (P,01) in CW210. Our results

6 PRODUCTIVITY OF DIFFERENT BREED TYPE COWS 1155 are comparable to those of Rutledge et al. (1971) and Gregory et al. (1979). Dam's weight change from calving to 130 d and from 130 to 210 d, respectively, influenced (P.01) ADG1 and ADG2. Also, dam's weight at 130 d postcalving affected (P.01) CW130, and dam's weight at weaning influenced (P.01) CW210 (table 2). There were no (P>.05) differences between individual regressions of the four dam breed types. Average cow weights at 130 d postcalving were 475, 498, 444 and 486 kg, for AH, CH, HH and SH females, respectively; the overall mean was 477 kg. CH dams tended to gain the most weight (30.6 kg) from calving to 130 d, while SH cows gained the least (18.4 kg). Gains of AH and HH dams were intermediate (22.8 and 26.4 kg, respectively). AH, CH, HH and SH dams averaged 481, 504, 457 and 494 kg, respectively, at the time their calves were weaned, with an overall mean of 485 kg. Wilson et al. (1969) reported that body size or weight was not a significant source of variation in milk production among Angus Holstein cows. Other researchers (Rutledge et al., 1971; Marshall et al., 1976) have reported a strong association between cow weight and calf weaning weight. In general, they have shown that as cow weight increases, weaning weight also increases. Stewart and Martin (1981) also found a positive association (P.01) between cow weight and calf weaning weight, but number of calves produced decreased (P.05). Weight change of dams from 130 to 210 d postcalving influenced (P.01) ADG2. HH females tended to gain the most weight (13.2 kg). Weight change of other breed types was fairly constant, with gains of 5.9, 5.7 and 7,9 kg, for AH, CH and SH females, respectively. Interactions affecting (P.05) ADG1 and CW130 were breed of dam x sex of calf, age of dam birth year of calf and sire breed x breed of dam. Results in table 3 show no difference (P>.05) in the performance of male and female calves from HH dams. Male calves from all other dam breed types had higher ADG1 and CW130 than female calves, with males from SH dams holding the greatest advantage (P.01) for both traits. These results may imply that superior maternal ability-namely high milk production-is necessary for male calves to express fully a superiority in growth over female progeny. The greatest difference in CW130 between sire breeds (15.5 kg) was observed among progeny of AH females (table 4). Calves from SH dams produced by C sires had the highest (P.05) CW130 (167.3 kg) and progeny of HH females and Angus sires had the lowest (123.2 kg). Breed of sire did not influence ADG1 of calves from HH, CH and SH females. However, three-breed cross C-sired progeny from AH dams gained faster (P.05) than backcross A-sired calves (table 4). The interaction of breed of sire breed of dam also influenced (P.05) CW210. Calves out of SH dams by Charolais sires were heavier (P.05) than calves of all other breed types. On the other hand, progeny of HH dams and Angus sires weighed the least (P.05). Within dam breed type, the largest sire-related difference in CW210 was observed among progeny of AH females; Charolais AH calves were 21.7 kg heavier than Angus x AH calves. No difference (P>.05) in CW210 was observed between AH and CH females mated to Charolais bulls. A difference (P.05) did exist between these same breed types when they were mated to Angus sires. The interaction of breed of dam x age of dam affected (P.05) ADG2. Among 2-yr-old TABLE 5. ANALYSIS OF VARIANCE OF COW PRODUCTIVITY CHARACTERS Mean squares Calf weaned/ Source df Weaning rate cow exposed Breed of cow (C) Year entered herd (Y) 3 5 3,347"* ,248* * 6,596 C Y Remainder ,737 1,189 8,167 5,522 **P.01.

7 1156 NELSON ET AL. dams, CH and SH progeny gained faster (P.05) than calves from AH and HH dams. Among 3- and 4-yr-olds, progeny of SH dams were superior (P.05) in ADG2 (.88 kg), those of AH and CH were intermediate (.77 and.79, respectively) and calves of HH dams gained (P.05) least rapidly (.67 kg). Melton et al. (1967) found that age of dam affected (P.01) milk yield, but dam's age had no affect on gain of Angus, Charolais or Hereford calves. Gaskins and Anderson (1980) observed similar increases in milk yield with increasing cow age when comparing 2-, 3- and 4-yr-old AH and Jersey x Hereford females. There was no influence of dam's age on ADG2 (P>.05) among progeny of AH, CH and HH females in our study, but ADG2 of calves from 3- to 7-yr-old SH dams was higher (P.05) than that of 2-yr-olds. It appears that cow age, and possibly total milk yield, may have had only limited effects on calf performance to 130 or 210 d of age. Perhaps most of the differences in ADG2 can be attributed mainly to the genotype of the calf inherited from the dam and sire rather than to environmental factors9 Weaning Rate. Weaning rate (WR) was defined as number of calves weaned/100 cows exposed in the breeding pasture. Weaning rate is a product of calving rate and calf survival and is one of the traits of greatest economic importance in beef production. Mean squares for WR are presented in table 5 and least-squares means are presented in table 6. SH dams had the highest (P.05) WR (83.4%) and HH females the lowest (66.4%). AH and CH cows were intermediate, weaning 76.8 and 77.7 calves, respectively, for each 100 cows exposed (table 6). F~ dams (AH, CH, SH) showed a 12.8 percentage point advantage (P.01) over HH dams. Gaines et al. (1978) reported that straightbred cows weaned.7% more calves than did crossbreds, whereas Cundiffet al. (1974a) found that crossbred cows weaned 6.4% more calves than straightbreds. A 9.0% advantage in WR for crossbreds was reported by Gaines et al. (1971). All of these studies included only British breeds and crosses. In our study, the WR of dairy x beef (SH) cows was 9.7 percentage points higher (P.01) than the average of beef beef females (AH, CH, HH). Our results are similar to those of Patterson et al. (1974), who reported WR of 88.9% for SH and 80 and 81% for CH and HH females, respectively. Belcher and Frahm (1979) obtained a higher WR (16.8 percentage points) u~ >, o +t z b-.a o~ r~ x ca C~ N t~v..= ~, ~ v o 6 Z l +l 8 ~a "d e~ o- z e~ o. v e~ i i ~a e- 6~ u e~

8 PRODUCTIVITY OF DIFFERENT BREED TYPE COWS 1157 with dairy x beef crossbred females. In contrast, Marshall et al. (1981) found no difference in WR between SH and AH cows. Calf survival to weaning tended to be greatest for SH dams, with only a 13.7 percentage point difference between conception rate (CR) and WR. Survival was lowest for straightbred Herefords, with a 30.3 percentage point difference (table 6). This difference includes all possible losses after conception, i.e., prenatal mortality, dystocia, twinning, failure to claim calf, accidental death, et cetera. It should be noted that 10 sets of twins were born from 1972 to 1977, of which seven were from SH cows and three were from CH dams. Meadows and Lush (1957) found a 11.3% twinning rate among Brown Swiss females. Cundiff et al. (1974a) reported a 6.4% advantage in calf crop weaned for British crossbreds over straightbreds and attributed it to increased pregnancy rate and first service CR among the crossbreds. Results from our study imply that the major difference in percentage calf crop weaned was due largely to calf losses related to dystocia (Nelson and Beavers, 1982) and subsequent survival to weaning. Kilograms of Calf Weaned per Cow Exposed. Quantity of calf weaned per cow exposed is an important economic trait because it indicates differences in total production per cow to weaning. It reflects differences in survival and growth of calves and reproductive performance and mothering ability of cows. The overall mean for kilograms of calf weaned/cow exposed (on a mid-sire and mid-sex basis) was kg. SH dams were the most productive (P.05) at kg/cow exposed, and HH cows were the least productive (P.05) with kg/cow exposed. AH and CH dams did not differ from each other in productivity to weaning. The average of values for the F 1 females was 50.7 kg (41%) greater (P.05) than that for HH dams. It should be noted that this difference reflects additive and heterosis differences between breed types. Spelbring et al. (1977) reported a 34.1-kg increase for reciprocal cross females over straightbred Angus and Milking Shorthorns. Weight of calf weaned/cowexposed was 14.8% greater for crosses among British breeds than for stralghtbreds (P.05) in the study by Cundiff et al. (1974a). In our study, dairy beef crossbreds (SH) were the most productive (P.05), averaging 47.6 kg (32%) more calf weaned/cow exposed than the average of AH, CH and HH dams. Comparable results were reported by Belcher and Frahm (1979) who found a 46.6 kg (37.5%) increase for Jersey cross and Brown Swiss Angus cows over HA reciprocal crosses. Patterson et al. (1974) found that SH cows weaned 49 kg more calf per exposure (P.01) than the average of HH and CH dams, whereas Frahm et al. (1981) showed only 15.4 kg advantage in calf weaned per exposure for SH vs AH cows. In a Canadian study, Fredeen et al. (1977) reported that CH and AH females weaned approximately the same amount of calf weight/ cow exposed. In our study, CH cows were 5% more productive (P>.05) than AH females. Holzgraefe et al. (1976), examining Jersey Hereford and Holstein Hereford crosses, found that the dairy x beef crosses were more productive, and attributed their advantage to higher weaning weights and more calves weaned/ cow exposed. It should be pointed out that only one management system and culling policy was employed in this study. In essence, this was a within management system comparison of different breed types. Under an alternative management system, reproduction or milk yield may be affected so as to result in a different breed type producing the most kilograms of calf weaned/cow exposed. General Discussion In general, three-breed cross calves were heavier at 210 d than backcross calves and backcrosses were heavier than two-breed cross calves. Ellis et al. (1979) found only a limited advantage of Charolais over Angus sires when they were mated to AH, CH and HH females, resulting in no differences (P>.05) in weaning weight between two-breed, three-breed and backcross calves. Gaines et al. (1978) reported that three-breed crosses among Angus, Hereford and Shorthorn breeds were heavier (P.01) at weaning than backcrosses. Peacock et al. (1981) computed production efficiency [(calf weaning weight + cow weight) x WR] and reported values of.43 for F 1 dams with threebreed cross calves,.40 for F1 cows raising backcrosses and.36 for purebred dams weaning Ft calves among breeds of British, European and Zebu origin. A comparison of average daily gain between birth and 130 d and between 130 and 210 d of age shows that performance of calves from HH and CH females tended to be fairly constant (table 2). On the other hand, progeny of AH and SH dams tended to gain proportionately

9 1158 NELSON ET AL. less during ADG2 than ADG1. This may suggest that AH and SH cows yielded more milk during the first 130 d of lactation than did HH and CH cows. If one compares ADG1 and ADG2 of calves by age of dam (table 2), one may conclude that the increase in cow's milk production as she matures is expressed largely during the first 130 d of lactation. The difference in performance between progeny of 2-yr-old dams and those of cows over 4 yr of age was.14 kg for ADG1 vs only.07 kg for ADG2. Although the differential between ADG1 and ADG2 tended to be greater for progeny of SH dams, it should be noted that these calves were 19% superior in both CW130 and CW210 to calves of beef-type dams (AH, CH, HH). Thus, continued growth (130 to 210 d) of calves from SH dams may be a function of the calf's genotype for growth as well as the maternal environment supplied by the cows; however, one should probably expect a greater differential in growth from birth to 130 d vs 130 to 210 d among calves from darns with higher milk yield potential. It would seem advantageous to utilize a larger, later-maturing sire breed for three-breed crosses if calving problems are held within reasonable limits; however, Nelson and Beavers (1982) reported greater (P.05) dystocia among cows mated to Charolais sires. The advantage of complementarity in crossbreeding systems can be illustrated (table 4) by a comparison of the calves from AH females and Charolais sires (CW210 = 212 kg) with those from CH cows and Angus sires (CW210 = 199 kg). There was a 13-kg difference in 210-d weight of calves that had the same breeds represented in their genotypes but in different proportions. Regardless of the crossbreeding strategy, there was a decided advantage for F 1 dams (AH, CH, SH) over Hereford dams in this study. In a comparison of crossbreeding systems, Gregory and Cundiff (1980) concluded that a three-breed rotation among young cows to produce herd replacements, combined with a terminal-sire system on mature cows, should increase weight marketed per cow exposed by 24.2% over a straightbred system. In general, SH dams exceeded AH and CH dams in both weaning weight of calf and weaning percentage. By our results, about 80 SH cows would produce the same weight of calf per year as 95 CH or 100 AH females. On the basis of WR, the replacement rate for AH and CH females was 6 percentage points higher than that for SH females (23 vs 17%) and the replacement rate for HH females was twice as great as that for SH. It appears that, based on this study, SH cows should generate the most income for the beef producer for a given unit of input. However, it has been reported (Lemenager et al., 1980) that SH females require additional feed for maintenance and for milk production. Thus, fixed costs should be the same for each female, but variable costs (feed) fluctuate among breed types because of differences in body size and milk yield potential. The net benefit derived from the use of heavier milking breeds depends upon economic comparison of extra output (calf weight) vs extra input (feed); however, Bowden (1980), examining Simmental Angus, Jersey Angus, CA and HA cows, found no difference among breed types in consumption (cow + calf) of digestible energy/kg of calf weaned. Our study provides additional data which should aid producers in calculating cost-return budgets to determine which kind of cow is best suited to their herd management programs. L iterature Cited Belcher, C. G. and R. R. Frahm Productivity of two-year old crossbred cows producing threebreed cross calves. J. Anita. Sci. 49:1195. Bowden, D. M Feed utilization for calf production in the first lactation by 2-year-old F 1 crossbred beef cows. J. Anim. Sci. 51:304. Cundiff, L. V., K. E. Gregory and R. M. Koch. 1974a. Effects of heterosis on reproduction in Hereford, Angus and Shorthorn cattle. J. Anita. Sci. 38:711. Cundiff, L. V., K. E. Gregory, F. J. Schwulst and R. M. Koch. 1974b. Effect of heterosis on maternal performance and milk production in Hereford, Angus and Shorthorn cattle. J. Anita. Sci. 38:728. Ellis, W. W., M. R. Ellersieck, L. Langford, B. Sibbit and J. F. Lasley Effects of mating systems on weaning traits in beef cattle. J. Anita. Sci. 48:7. Frahm, R, R., D. M. Marshall and C, G. Chenette Productivity comparisons among various two-breed cross cow groups. Oklahoma Agr. Exp. Sta. Res. Rep. MP-108:30. Fredeen, H. T., J. E. Lawson, J. A. Newman and G. W. Rahnefeld Reproductive performance of foreign domestic hybrid cows under two management systems. Canada Dept. of Agr. Pub Gaines, J. A., R. C. Carter, W. H. McClure and E. A. Tolley Straightbreeding versus crossbreeding of beef cattle. J. Anim. Sci. 33:200 (Abstr.). Gaines, J. A., C. Hill, W. H. McClure, R. C. Carter and W. T. Butts Heterosis from crosses among British breeds of cattle: Straightbred versus crossbred cows. I. J. Anita. Sci. 47:1246.

10 PRODUCTIVITY OF DIFFERENT BREED TYPE COWS Gaines, J. A., W. H. McClure, D. W. Vogt, R. C. Carter and C. M. Kincaid Heterosis from crosses among British breeds of beef cattle: Fertility and calf performance to weaning. J. Anim. Sci. 25:5. Gaskins, C. T. and D. C. Anderson Comparison of lactation curves in Angus-Hereford, Jersey- Angus and Simmental-Angus cows. J. Anim. Sci. 50:828. Gregory, K. E. and L. V. Cundiff Crossbreeding in beef cattle: Evaluation of systems. J. Anim. Sci. 51:1224. Gregory, K. E., L. V. Cundiff, G. M. Smith, D. B. Laster and H. A. Fitzhugh, Jr Characterization of biological types of cattle-cycle II. I. Birth and weaning traits. J. Anim. Sci. 47:1022. Gregory, K. E., G. M. Smith, L. V. Cundiff, R. M. Koch and D. B. Laster Characterization of biological types of cattle-cycle III. I. Birth and weaning traits. J. Anita. Sci. 48:271. Harvey, W. R User's guide for LSML76. The Ohio State Univ., Columbus (Mimeo). Holloway, J. W., D. F. Stephens, J. V. Whiteman and R. Totusek Performance of 3-year-old Hereford, Hereford X Holstein and Holstein cows on range and in drylot. J. Anita. Sci. 40:114. Holzgraefe, D. P., J. W. Waggoner, Jr., G. G. Cmarik and A. L. Neumann Performance of straightbred and crossbred cows. J. Anita. Sci. 43:218 (Abstr.). Knapp, B. W., O. F. Pahnish, J. J. Urick, J. S. Brinks and G. V. Richardson Preweaning and weaning heterosis for maternal effects of beef beef and beef X dairy crosses. J. Anim. Sci. 50:800. Kropp, J. R., D. F. Stephens, J. W. Holloway, J. V. Whiteman, L. Knori and R. Totusek Performance on range and in drylot of twoyear-old Hereford, Hereford Holstein and Holstein females as influenced by level of winter supplementation. J. Anita. Sci. 37:1222. Lemenager, R. P., L. A. Nelson and K. S. Hendrix Influence of cow size and breed type on energy requirements. J. Anim. Sci. 51:566. Long, C. R. and K. E. Gregory Heterosis and breed effects in preweaning traits of Angus, Hereford and reciprocal cross calves. J. Anita. Sci. 39:11. Marlowe, T. J. and J. A. Gaines The influence of age, sex and season of birth of calf, and age of dam on preweaning growth rate and type score of beef calves. J. Anim. Sci. 17:706. Marshall, D. M., R. R. Frahm and C. G. Chenette Reproductive performance of various two-breed cross cow groups. Oklahoma Agr. Exp. Sta. Res. Rep. MP--108:27. Marshall, D. A., W. R. Parker and C. A. Dinkel Factors affecting efficiency to weaning in Angus, Charolais and reciprocal cross cows. J. Anim. Sci. 43:1176. McGinty, D. D. and W. G. Frerichs Milk yields and calf performance from crossbred and Hereford cows. J. Anim. Sci. 33:210 (Abstr.), Meadows, C. E. and J. L. Lush Twinning in dairy cattle and its relation to production. J. Dairy Sci. 40:1430. Melton, A. A., J. K. Riggs, L. A. Nelson and T. C. Cartwright Milk production, composition and calf gains of Angus, Charolais and Hereford cows. J. Anim. Sci. 26:804. Nelson, L. A. and G. D. Beavers Beef X beef and dairy beef females mated to Angus and Charolais sires. I. Pregnancy rate, dystocia and birth weight. J. Anita. Sci. 54:1138. Notter, D. R., L. V. Cundiff, G. M. Smith, D. B. Laster and K. E. Gregory Characterization of biological types of cattle. VII. Milk production in young cows and transmitted and maternal effects on preweaning growth of progeny. J. Anim. Sci. 46:908. Pahnish, O. F., J. S. Brinks, J. J. Urick, B. W. Knapp and T. M. Riley Results from crossing beef X beef and beef dairy breeds: Calf performance to weaning. J. Anim. Sci. 28:291. Parker, C. F. and R. W. Van Keuren Effects of forage system and breed type on the performance of fall calving cows. Ohio Res. Circ Patterson, T. B., J. A. McGuire and R. A. Moore Effects of Brown Swiss, Charolais, Holstein and Hereford breeding on production in a grade beef herd. Auburn Univ. Agr. Exp. Sta. Bull Peacock, F. M., M. Koger, T. A. Olson and J. R. Crockett Additive genetic and heterosis effects in crosses among cattle breeds of British, European and Zebu origin. J. Anita. Sci. 52:1007. Rutledge, J. J., O. W. Robison, W. T. Ahlschwede and J. E. Legates Milk yield and its influence on 205-day weight of beef calves. J. Anita. Sci. 33:563. Smith, G. M., D. B. Laster and K. E. Gregory. i976. Characterization of biological tpes of cattle. I. Dystocia and preweaning growth. J. Anita. Sci. 43:27. Spelbring, M. C., T. G. Martin and K. J. Drewry Maternal productivity of crossbred Angus Milking Shorthorn Cows. II. Cow reproduction and longevity. J. Anim. Sci. 45:976. Stewart, T. S. and T. G. Martin Mature weight, maturation rate, maternal performance and their interrelationships in purebred and crossbred cows of Angus and Milking Shorthorn parentage. J. /Maim. Sci. 52:51. Wilson, L. L., J. E. Gillooly, M. C. Rugh, C. E. Thompson and H. R. Purdy Effects of energy intake, cow body size and calf sex on composition and yield of milk by Angus-Holstein cows and preweaning growth of progeny. J. Anim. Sci. 28:789.