| Table 1. Variance analyses for reproduction and production traits. | ||||||
| Source of variance | d.f. | Pregnancy | Survival | Calf weaning age | Calf weaning weight | 205-day weight |
| Years | 6 | 0.442** | 0.016 | 2856** | 3032** | 3389** |
| Sex | 1† | - | - | 1352 | 15661** | 17908** |
| Dam age | 2 | 0.446* | 0.173* | 3036* | 960 | 824* |
| Sire breed | 2 | 0.302* | 0.164 | 3392* | 9212** | 5868** |
| F1 dam breed†† | 2 | 0.476** | 0.048 | 656 | 1495* | 2358 |
| R-AB dams‡ | 1 | 0.000 | 0.041 | 1433 | 226 | 54 |
| R-AC dams | 1 | 0.015 | 0.024 | 456 | 130 | 482 |
| R-BC dams | 1 | 0.112 | 0.038 | 2194 | 392 | 50 |
| Remainder | 571‡‡ | 0.098 | 0.056 | 833 | 493 | 249 |
| †d.f. only for production traits. | ||||||
| †† F1 dam reciprocals combination. | ||||||
| ‡Reciprocal F1 | ||||||
| ‡‡Remainder d.f. for survival is 500 and for calf data 468. | ||||||
| * P<0.05 | ||||||
| ** P<0.01 | ||||||
Least-squares means and standard error for traits measured are presented in Table 2.
There were highly significant differences for the F1 dam breeds (reciprocals combined) for pregnancy, with no differences observed for survival rate of calves. Pregnancy rates were 91.2% for AB + BA, 81.2% for AC + CA, and 89.4% for BC + CB F1 dam breeds. Pregnancy rates for the Brahman cross dams were similar, and higher than those of the Angus-Charolais crosses.
No significant differences in pregnancy or calf survival were observed among the reciprocals (Table
1). The only reciprocals showing any degree of possible maternal superiority in the performance of
their F1 female progeny were the Charolais x Brahman (CB) at 92.0% over the Brahman x Charolais
(BC) at 86.9% (Table 2). The reciprocals, whether CB (Charolais bull x Brahman cow) or BC
(Brahman bull x Charolais cow), should be the same genetically. The possibility exists that differences
could be due to the maternal environment provided by the Brahman to their F1 female progeny in
utero or during the period from birth to weaning.
There were no differences observed for weaning age of calves among the F1 dams (reciprocals combined). This indicates that all F1 dams that conceived did so during the same time period (Table 1). There were also no significant differences among the F1 reciprocals for weaning age of their calves.
Weaning weights and 205-day weights of calves from the three F1 crossbred combinations
(reciprocals combined) were significantly different (Table 1). The weights for calves from F1 AB +
BA and F1 BC + CB cows were similar and were higher (P * 0.01) than calves produced by F1 AC
+ CA cows (Table 2).
Even though variations were real between breed combinations, there were no observed differences
between F1 breed reciprocals (Table 2). There was, however, a tendency for F1 dams produced from
Brahman dams to wean heavier calves, but when adjusted for calf age, these small variations were
minimized. Turner et al. (8) reported no differences in the weaning weight of calves between F1
Angus x Brahman vs Brahman x Angus reciprocal dams in Louisiana, but they did suggest a tendency
for F1 dams from Brahman cows to be superior. Results from the Charolais-Angus combinations
(Table 2) showed that F1 cows from Charolais dams (AC) appeared to have a slight advantage for
205-day calf weight (450 vs 438 lb [204 vs 199 kg]) These variations suggest the possibility that
reciprocal differences are related to dam size, as the Charolais cows weighed 1076 lb (488 kg) vs 855
lb (388 kg) for the Angus (Table 4). Montana research (Pahnish et al., 4) on the same breed
combination did not find differences in 205-day weight of calves from F1 reciprocal Charolais-Angus
crossbred dams, even though the Charolais were 10% heavier than Angus dams.
| Table 2. Reproduction and production traits of reciprocal F1 dams of the Angus (A), Brahman (B), and Charolais (C) breeds. | ||||||||
| Breed Group | Number of observations | Pregnancy (%) | Number of observations | Calf survival (%) | Number of observations | Calf age (days) | Weaning weight (lb)t | 205-day weight (lb)t |
| F1 dams††, ‡ | ||||||||
| AB, BA | 218 | 91.2 ± 2.7 | 202 | 95.6 ± 2.1 | 193 | 224.3 ± 2.7 | 503.3 ± 6.4 | 467.5 ± 4.6 |
| AC, CA | 185 | 81.2 ± 2.5 | 149 | 91.9 ± 2.1 | 138 | 228.4 ± 2.7 | 484.0 ± 6.4 | 443.6 ± 4.6 |
| BC, CB | 184 | 89.4 ± 2.5 | 165 | 92.9 ± 2.0 | 154 | 224.7 ± 2.5 | 501.7 ± 6.0 | 466.3 ± 4.3 |
| Reciprocal F1 Dams | ||||||||
| AB | 171 | 91.4 ± 2.6 | 159 | 93.8 ± 2.1 | 151 | 227.6 ± 2.6 | 507.5 ± 6.2 | 465.5 ± 4.4 |
| BA | 47 | 91.1 ± 4.6 | 43 | 97.3 ± 3.7 | 42 | 220.9 ± 4.5 | 499.1 ± 11.0 | 469.6 ± 7.8 |
| AC | 113 | 82.1 ± 3.0 | 92 | 93.2 ± 2.5 | 86 | 226.5 ± 3.2 | 487.1 ± 7.8 | 449.8 ± 5.5 |
| CA | 72 | 80.2 ± 3.8 | 57 | 90.5 ± 3.2 | 52 | 230.3 ± 5.1 | 480.8 ± 10.0 | 437.5 ± 7.1 |
| BC | 78 | 86.9 ± 3.7 | 67 | 94.5 ± 3.0 | 64 | 220.8 ± 3.7 | 496.4 ± 9.0 | 468.1 ± 6.4 |
| CB | 106 | 92.0 ± 3.2 | 98 | 91.3 ± 2.5 | 90 | 228.6 ± 4.0 | 506.9 ± 7.7 | 464.4 ± 5.4 |
| † kg = lb x 0.454 | ||||||||
| †† Last letter of pair is dam breed, AB = Angus sire x Brahman dam, BA = Brahman sire x Angus dam. | ||||||||
| ‡ Reciprocals combined. | ||||||||
Research on maternal effects for weaning weight of reciprocal F1 calves was conducted in Florida by Peacock et al. (6). With the Angus-Brahman combinations, F1 calves produced by Brahman dams were 5.8% heavier (P < 0.05) at weaning than those from Angus dams, but when adjusted for age, the difference (3.5%) was not significant (Table 3). The variation (P < 0.10) in weight of these reciprocals existed at 2 years of age (Peacock and Koger, 5), and also at maturity (Table 4). The positive effect of the Brahman dam on preweaning response of calves was greater in the Charolais-Brahman crosses. Calves from Brahman dams weighed 8.5% more (P < 0.01) at weaning, and 4.4% more (P < 0.05) when calf weights were adjusted for age, than the reciprocals from Charolais dams. However, this advantage diminished to 3.5% (non-significant) at 2 years of age and was completely gone at maturity. These results do not support the theory that maternal effect is caused by difference in dam breed size, since Charolais dams weighed 13.7% more than Brahman dams (Table 4). However, heterosis for growth of offspring was obtained when the Brahman and European cattle were crossed, and the hybrid vigor effects masked the maternal effects for growth.
| Table 3. Mean differences and standard errors of mean differences for calf weights between purebred, between reciprocal F1 calves, and between calves of reciprocal F1 cows. | ||||||
| Calf weaning weight | Calf 205-day weight | |||||
| Breed groups | lb† | Mean difference | % | lb† | Mean difference | % |
| Purebreds | ||||||
| Brahman (B) - Angus (A) | (398.5 - 403.8) | -5.3 ± 12.3 | 1.3 | (384.7 - 366.6) | 18.1 ± 8.9* | 4.9 |
| Charolais (C) - Angus (A) | (491.7 - 403.8) | 89.9 ± 12.1** | 21.8 | (465.5 - 366.6) | 98.9 ± 8.8** | 27.0 |
| Charolais - Brahman | (491.7 - 398.5) | 93.2 ± 11.5** | 23.4 | (465.5 - 384.7) | 80.8 ± 8.3** | 21.0 |
| Reciprocal F1 calves† † | ||||||
| AB - BA | (452.9 - 428.0) | 24.9 ± 12.8 | 5.8 | (427.5 - 412.9) | 14.6 ± 9.3 | 3.5 |
| AC - CA | (477.6 - 449.5) | 28.1 ± 13.0* | 6.2 | (457.1 - 406.3) | 50.8 ± 9.4** | 12.7 |
| CB - BC | (503.4 - 464.0) | 39.4 ± 12.0** | 8.5 | (474.8 - 454.7) | 20.1 ± 8.8* | 4.4 |
| Reciprocal F1 cows‡ | ||||||
| AB - BA | (507.5 - 499.1) | 8.4 ± 12.6 | 1.7 | (465.5 - 469.6) | -4.1 ± 9.0 | 0.8 |
| AC - CA | (487.1 - 480.8) | 6.3 ± 12.7 | 1.3 | (449.8 - 437.5) | 12.3 ± 9.0 | 2.8 |
| CB - BC | (506.9 - 496.4) | 10.5 ± 11.8 | 2.1 | (464.4 - 468.1) | -3.7 ± 8.4 | 0.8 |
| † kg = lb x 0.454 | ||||||
| †† Last letter of pair is dam breed, AB = Angus sire x Brahman dam, BA = Brahman sire x Angus dam; AB-BA = Angus sire x Brahman dam minus Brahman sire x Brahman dam. | ||||||
| ‡ Calves of reciprocal F1 cows. | ||||||
| * P<0.05 | ||||||
| ** P<0.01 | ||||||
Research has shown no heterosis for calf weaning weight in combined F1 reciprocals from crossing the Charolais and Angus breeds (Peacock et al., 6). The Charolais and Angus are both European breeds, even though large differences existed in mature size. The Charolais cow was 25.8% heavier than the Angus 1076 vs 855 lb (488 vs 388 kg). Reciprocal crossing resulted in Charolais cows producing 13% more calf than the Angus cow, 6.2% more when the calves reached 2 years of age. At maturity this F1 Angus x Charolais cow weighed 5.0% more (P < 0.01) than its reciprocal from Angus cows. Even though real differences did not occur among offspring of these reciprocal Charolais-Angus cows, additivity for dam breed size was present in F1 cows, diminishing in the succeeding generation until equilibrium was reached.
Weights of reciprocal F1 females out of Brahman cows at 2 years of age slightly favored the
Brahman dam over Angus and Charolais dams (nonsignificant), with the influence of the Charolais
dam over the Angus diminished in the F1 but still at a 6.1% advantage (P < 0.05) over the Angus
(Peacock and Koger 5).
The concept of maternal effects on size and growth of beef cattle offspring was probably based on
studies of growth behavior in the horse. Research in the United Kingdom (Walton and Hammond,
9) showed that crossbred foals from Shetland mares were smaller at birth and remained smaller at all
subsequent stages of development than their reciprocal crosses from Shire mares. This was attributed
to the fact that leg length from the knee and hock downwards increased very little after birth, and the
size to which the reciprocal crosses grew was affected accordingly. However, beef cattle research
(Joubert 2) showed that the knee and hock heights increased by 55.9% and 56.0% respectively from
birth to maturity, which indicates that differences in size at birth may not remain permanent but might
be altered by compensatory growth.
Further research on maternal influence by Joubert and Hammond (3) utilized two breeds of beef
cattle of an extreme size difference, the South Devon and Dexter. The average adult South Devon
female weighed 1568 lb (712 kg) and the Dexter 650 lb (295 kg), a difference of 241%. Birth
weight of Dexter calves was 51.8 lb (23.5 kg), whereas for South Devon calves it was 100.3 lb
(45.5 kg), a 96.3% difference. Reciprocal crossbred calves from South Devon cows weighed
12.5% more at birth than calves from Dexter cows. The difference increased to 28.6% at 7
months of age and was 16.5% at 12 months. Results from this study show that maternal effects
due to dam size exist in the offspring and could continue into adult life.
Actual cow weights may not be the true genetic size of the breeds used in this study. The variations
in environmental conditions existing in the United States could be involved in producing important
effects of genotype-environment interaction on actual weight. In Montana (Pahnish et al., 4),
Charolais cows were only 10% heavier than Angus, whereas in Missouri (Sagebiel et al., 7) the
difference was 23%, and at Ona, Florida (Peacock et al., 6), the difference was 26%.
| Table 4. Mean differences and standard error of differences, and percentage differences for weights between purebred, and between reciprocal F1 cows at mature weight. | |||||||
| Purebred cow | Reciprocal F1 cow† | ||||||
| Breed groups | lb†† | Mean difference | % | Breeds | lb‡ | Mean difference | % |
| Brahman (B) - Angus (A) | (947-855) | 92 ± 11.5** | 10.8 | AB-BA | (987-954) | 33 ± 18.6 | 3.5 |
| Charolais (C) - Angus | (1076-855) | 221 ± 12.1** | 25.8 | AC-CA | (1006-958) | 48 ± 17.6** | 5.0 |
| Charolais - Brahman | (1076-947) | 129 ± 12.2** | 13.6 | BC-CB | (1057-1048) | 9 ± 15.3** | 0.9 |
| † AB-BA = Mature progeny of A x B vs. B x A. | |||||||
| †† kg = lb x 0.454 | |||||||
| ** P<0.01 | |||||||
The results from this study and those from the United Kingdom on crossing breeds with large variations in genetic size show that maternal effects on size are transmitted to offspring when genetic effects are additive and performance of offspring is void of heterosis. However, when crossing genetically divergent breeds where a high degree of heterosis for growth is obtained, maternal effects on size could be masked. Even though maternal effects might occur in the first cross, these effects would diminish in the next generation (offspring from F1 cross females), with little grand-dam maternal effects in the offspring.
Data have been presented for reproduction and production performance of reciprocal F1 crossbred cows representing the Angus, Brahman, and Charolais breeds. Results of this research showed no significant differences between F1 reciprocal cows for traits measured. Therefore, under the environmental conditions of this study and with the breeds utilized, the production potential of the F1 cross female was not significantly affected by dam breed. Under environmental conditions similar to this study, Brahman bulls can be mated to Angus cows or Angus bulls can be mated to Brahman cows without materially affecting the performance of the resulting F1 females. The same principle exists in the production of the other breed combinations represented in this study. However, under conditions where the dam breed is not adapted, and growth of offspring F1 female) is so severely retarded that its genetic potential for growth is not reached, its ultimate production could be affected. These conditions would warrant the selection of the dam breed that is most adapted to the environment to ensure that the potential of the F1 female is reached.
- Harvey, W. R. 1975. Least squares analyses of data with unequal subclass numbers. USDA
ARS. 11-4.
- Joubert D. M. 1954. The influence of winter nutrition depression on growth, reproduction and
production of cattle. J. Agr. Sci. 44:5.
- Joubert, D. M., and John Hammond. 1958. A crossbreeding experiment with cattle with special
reference to maternal effects on South Devon-Dexter crosses. J. Agri. Sci. 51:325.
- Pahnish, O. F., J. S. Brinks, J. J. Urick, B. W. Knapp, and T. M. Riley. 1969. Results from crossing
beef x beef and beef x dairy breeds: calf performance to weaning. J. Anim. Sci. 28:291.
- Peacock, F. M., and M. Koger. 1982. Heterosis for weight in F1 crosses of the Angus, Brahman
and Charolais breeds as long yearlings (unpublished data).
- Peacock, F. M., M. Koger T. A. Olson, and J. R. Crockett. 1981. Additive genetic and heterosis
effects in crosses among cattle breeds of British, European and Zebu origin. J. Anim. Sci. 52:1007.
- Sagebiel, J. A., G. F. Krouse, Bob Sibbit, L. Langford, A. J. Dyer, and John F. Lasley. 1973. Effect
of heterosis and maternal influence on gestation length and birth weight in reciprocal crosses
among Angus, Charolais and Hereford cattle. J. Anim. Sci. 37:1273.
- Turner, J. W. 1969. Preweaning production differences among reciprocal crossbred beef cows. J.
Anim. Sci. 29:857.
- Walton, A., and J. Hammond. 1938. The maternal effect on growth and conformation in Shire horse-Shetland pony crosses. Proc. Roy. Soc. (Biol.) 125:311.
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