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1.
The objective of this study was to characterize breeds representing diverse biological types for birth and weaning traits in crossbred cattle (Bos taurus). Gestation length, calving difficulty, percentage of unassisted calving, percentage of perinatal survival, percentage of survival from birth to weaning, birth weight, weaning weight, BW at 205 d, and ADG was measured in 1,370 calves born and 1,285 calves weaned. Calves were obtained by mating Hereford, Angus, and MARC III (1/4 Hereford, 1/4 Angus, 1/4 Pinzgauer, and 1/4 Red Poll) mature cows to Hereford or Angus (British breeds), Norwegian Red, Swedish Red and White, Wagyu, and Friesian sires. Calves were born during the spring of 1997 and 1998. Sire breed was significant for gestation length, birth weight, BW at 205 d, and ADG (P < 0.001). Offspring from Swedish Red and White and Friesian had the shortest gestation length (282 d), whereas offspring from Wagyu sires had the longest gestation length (286 d). Progeny from British breeds were the heaviest at birth (40.5 kg) and at 205 d (237 kg), and grew faster (0.97 kg/d) than offspring from other breeds. Offspring from Wagyu sires were the lightest at birth (36.3 kg) and at 205 d (214 kg), and had the slowest growth (0.91 kg/d). Dam breed was significant for gestation length (P < 0.001), birth weight (P = 0.009), BW at 205 d, and ADG (P < 0.001). Offspring from Hereford cows had the longest gestation length (284 d), whereas offspring from Angus cows had the shortest (282 d). Offspring from MARC III cows were the heaviest at birth (39.4 kg) when compared with offspring from Hereford (38.2 kg) and Angus (38.6 kg) cows. Progeny from Angus cows were the heaviest at 205 d (235 kg) and grew faster (0.96 kg/d), whereas offspring from Hereford cows were the lightest at 205 d (219 kg) and were the slowest in growth (0.88 kg/d). Sex was significant for gestation length (P = 0.026), birth weight, BW at 205 d, and ADG (P < 0.001). Male calves had a longer gestation length (284 d) when compared with female calves (283 d). Males were heavier than females at birth and at 205 d, and grew faster. Sire breed effects can be optimized by selection and use of appropriate crossbreeding systems.  相似文献   

2.
The objective of this study was to characterize breeds representing diverse biological types for postweaning growth and carcass composition traits in terminal crossbred cattle. Postweaning growth and carcass traits were analyzed on 434 steers and 373 heifers obtained by mating F1 cows to Charolais sires. Maternal grandsires represented Hereford, Angus, and MARC III (1/4 Hereford, 1/4 Angus, 1/4 Pinzgauer, and 1/4 Red Poll) dams to Hereford or Angus (British Breeds), Norwegian Red, Swedish Red and White, Wagyu, or Friesian breeds. Breed groups were slaughtered serially in each of 2 yr (2002 and 2003). Postweaning ADG, slaughter weight, hot carcass weight, dressing percentage, percentage Choice, LM area, marbling score, USDA yield grade, fat thickness, retail product yield (percentage), retail product weight, fat yield (percentage), fat weight, bone yield (percentage), and bone weight were analyzed. Maternal grandsire breed was significant (P < 0.05) for all traits except dressing percentage, percentage Choice, and LM area. Marbling score for animals with Norwegian Red, Wagyu, Swedish Red and White, British Breeds, and Friesian inheritance was 550, 544, 532, 530, and 515, respectively (SEM = 8). Retail product weight for these animals was 224, 211, 227, 223, and 223 kg, respectively (SEM = 2 kg). Maternal granddam breed was not significant for any of the traits analyzed. Grandsire breed effects can be optimized by selection and use of appropriate crossbreeding systems.  相似文献   

3.
Growth and testicular development between 7 and 15 mo of age were evaluated in bulls produced by mating sires of six breeds (Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli) to Angus, Hereford, and MARC III (four-breed composite) cows. At 12 mo of age, Angus- and Hereford-sired bulls had the heaviest body weight (P < 0.08 to 0.001), whereas Brahman- and Belgian Blue-sired bulls were intermediate, and Boran- and Tuli-sired bulls weighed the least. Bulls sired by European breeds grew more rapidly after weaning (P < 0.01) than did Brahman-, Boran-, and Tuli-sired bulls, and these differences in growth rate were maintained through 15 mo of age, indicating that offspring of heat-adapted sire breeds (Brahman, Boran, and Tuli) have lower postweaning rates of gain, particularly during winter months, than do offspring of nonheat adapted sire breeds. Testis size was smaller initially (P < 0.01) and remained smaller in offspring of heat-adapted sire breeds through yearling age. By 15 mo of age, testis size was largest (P < 0.06 to 0.001) in Angus-sired bulls and had become similar among Hereford-, Brahman-, Boran- and Belgian Blue-sired bulls but remained smaller (P < 0.02 to 0.001) in Tuli-sired bulls. Thus, offspring of heat-adapted sire breeds had delayed testicular development compared with that of nonheat adapted sire breeds, particularly through yearling age. At puberty, Angus-sired bulls were 23 to 82 d younger (P < 0.05 to 0.001) than all other sire breeds except Hereford, and Brahman-sired bulls were older at puberty (P < 0.05 to 0.001) than were bulls of all other sire breeds except Boran. Testis size at puberty was quite similar among breeds of bulls (scrotal circumference = 27.9 +/- 0.1 cm) despite large breed differences in age, body weight, and hip height. Thus, measurement of yearling testis size was a reliable indicator of age at puberty among widely divergent breeds of bulls. In addition, the lower postweaning rates of gain and the smaller and slower testicular development in offspring of heat-adapted sire breeds should be noted by cattle producers considering use of such breeds in crossbreeding and breed improvement programs.  相似文献   

4.
Feedlot traits, carcass traits and distribution of commercial cuts of crossbred intact male progeny (n = 556) from young and mature Hereford, Red Poll, Hereford X Red Poll, Red Poll X Hereford, Angus X Hereford, Angus X Charolais, Brahman X Hereford and Brahman X Angus dams were evaluated. First-calf heifers were bred to Red Angus bulls; Santa Gertrudis sires were used for each cow's second and third breeding seasons. Calves from these young dams were slaughtered at 13 mo. Calves of mature dams were all sired by Limousin bulls and slaughtered at 12 mo. Dam breed was a major source of variation in most bull traits. Progeny of Brahman-cross dams were inferior (P less than .01) in daily gain, final weight, carcass weight and in edible cuts/day of age compared with progeny from Bos taurus dams. Intact male progeny of Angus X Charolais dams ranked highest in longissimus area, cutability, and edible cuts/day of age. The range of dam breed means in percentage of steak, roast, bone-in cuts (chuck short ribs and back ribs), short plate and thin cuts, and lean trim was just over 1%. Greater variation among dam breeds existed in fat measurements. Analyses in which Hereford-Red Poll diallel data for young dams and mature dams were combined showed positive maternal heterosis for dressing percentage (P less than .05), carcass weight (P less than .05), carcass weight/day of age (P less than .05), estimated carcass fat (P less than .05), fat thickness (P less than .01) and marbling score (P less than .01). Reciprocal effects were inconsequential. Results illustrate the importance of dam breed-type effects in formulating breeding strategies for commercial beef herds.  相似文献   

5.
The objective of this study was to assess the association of SNP in the thyroglobulin gene, including a previously reported marker in current industry use, with marbling score in beef cattle. Three populations, designated GPE6, GPE7, and GPE8, were studied. The GPE6 population sampled breeds that could be used as alternative germplasm sources in beef cattle production, including Wagyu, Swedish Red and White, Friesian, and Norwegian Red. The GPE7 population sampled 7 popular beef cattle breeds used in temperate climates of the United States: Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental. The GPE8 population sampled Bos indicus-influenced breeds used in subtropical regions of the country and subtropical and tropical regions of the world, including Beefmaster, Bonsmara, Brangus, and Romosinuano. Evaluation of 6 SNP in the thyroglobulin gene, including 5 newly described variations, showed no association (P > 0.10) with marbling score in these populations, except a tendency (P < 0.10) for an association with the previously described marker in GPE6. Closer examination of the GPE6 data revealed that the source of the tendency was an association (P < 0.02) with marbling in animals of Wagyu inheritance. Animals having Wagyu background and inheriting the TT genotype had a greater marbling score (599 +/- 20) than those inheriting the CC (540 +/- 10) or the CT (541 +/- 11) genotype. No association was detected with any other carcass trait for this marker in the 3 populations. Furthermore, none of the 5 newly described markers in the gene displayed an association with marbling score. The data indicate that markers at the thyroglobulin gene may be a useful predictor of marbling performance for producers raising Wagyu-based cattle. Although associations with marbling score in the remaining populations were not large or significant, the TT genotype had the numerically greatest marbling score in each population.  相似文献   

6.
Carcass (n = 568) and longissimus thoracis palatability (n = 460) traits from F1 steers obtained from mating Hereford (H), Angus (A), and U.S. Meat Animal Research Center (MARC) III cows to H, A, Norwegian Red (NR), Swedish Red and White (RW), Friesian (F), or Wagyu (W) sires were compared. Data were adjusted to constant age (471 d), carcass weight (356 kg), fat thickness (1.0 cm), percentage of fat trim (24%), and marbling (Small35) end points. For Warner-Bratzler shear force and trained sensory panel traits, data were obtained on longissimus thoracis steaks stored at 2 degrees C for 14 d postmortem. The following comparisons were from the age-constant end point. Carcasses from H- and A-sired steers (377 and 374 kg, respectively) were the heaviest (P < 0.05) and carcasses from W-sired steers (334 kg) were the lightest (P < 0.05). A greater (P < 0.05) percentage of carcasses from A- and W-sired steers graded USDA Choice (88 and 85%, respectively) than carcasses from other sire breeds (52 to 71%). Adjusted fat thickness for carcasses from A-sired steers (1.3 cm) was highest (P < 0.05), followed by H-sired steers (1.1 cm) and W- and F-sired steers (0.9 cm); NR- and RW-sired steers (0.8 cm) had the lowest (P < 0.05) adjusted fat thickness. Longissimus thoracis area was not different (P > 0.05) among sire breeds (mean = 80.6 cm2). Carcass yield of boneless, totally trimmed retail product was least (P < 0.05) for A-sired steers (60.1%), intermediate for H-sired steers (61.5%), and similar (P > 0.05) for all other sire breeds (62.5 to 62.8%). Longissimus thoracis steaks from carcasses of A- (3.7 kg) and W-sired (3.7 kg) steers had lower (P < 0.05) shear force values than longissimus thoracis steaks from other sire breeds (4.1 to 4.2 kg). Trained sensory panel tenderness, juiciness, or beef flavor intensity ratings for longissimus thoracis steaks did not differ (P > 0.05) among the sire breeds. Sire breed comparisons were affected by adjusting data to other end points. Heritability estimates for various carcass, yield, and palatability traits ranged from very low (h2 = 0.06 for percentage of kidney, pelvic, and heart fat) to relatively high (h2 = 0.71 for percentage of retail product yield). Relative to the other sire breeds, W-sired steers had the highest percentage of USDA Choice, Yield grade 1 and 2 carcasses, but their carcasses were the lightest.  相似文献   

7.
The objective of this study was to determine if biostimulation of prepuberal beef heifers by mature bulls would alter proportions of heifers exhibiting puberty, or age or weight at puberty. Angus (A), A X Hereford (H) and Tarentaise X HA heifers (n = 103) were stratified by age and weight within breed-type and location of birth and allotted randomly to the following treatments: 1) heifers exposed to mature bulls (T1; n = 52) or 2) heifers isolated from bulls (T2; n = 51). At the start of the experiment, heifers in T1 and T2 were 287 +/- 2 and 286 +/- 2 d of age, respectively. Male-to-female ratio for T1 was 1:26. Heifers in T1 and T2 were maintained in drylots separated by .5 km. Heifers were observed for estrus twice daily for 152 d. Puberty was characterized by the following criteria: 1) behavioral estrus, 2) presence of a palpable corpus luteum (d 9; estrus = d 0) and 3) a rise in serum progesterone above 1 ng/ml (d 9). Proportions of heifers reaching puberty by 11, 12, 13, 14 and 15 mo of age did not differ (P greater than .10) between treatments. Percentages of heifers reaching puberty by the end of the experiment were 84 and 89% for T1 and T2, respectively. Age and weight at puberty did not differ (P greater than .10) between treatments and averaged 370 +/- 7 d and 293 +/- 4 kg, respectively. Results from this experiment indicated that presence of mature bulls did not alter proportions of beef heifers reaching puberty, or age and weight at puberty.  相似文献   

8.
Bull calves (n = 143) were obtained from two strains of Angus and two strains of Hereford cattle for which replacements were selected on the basis of superior feedlot growth performance on either high- or medium-energy diets. From weaning to slaughter at 15 mo of age, bulls were fed either the high-energy (80% grain + 20% forage) or medium-energy diet (100% forage) corresponding to their strain. Bulls in high-energy diet groups had a greater (P less than .05) scrotal circumference at 12 mo, but not 15 mo of age, than bulls in medium-energy diet groups. Compared with Hereford bulls, Angus had greater (P less than .01) scrotal circumference (36.1 vs 33.9 cm) and greater (P less than .05) paired testes weight (570 vs 464 g) at 15 mo of age. Daily sperm production per gram testicular parenchyma (DSP/g) was affected by strain-diet (P less than .01) but not by breed. Bulls in medium-energy diet groups had 12% greater DSP/g than did high-energy diet bulls (17.4 X 10(6) vs 15.5 X 10(6)). Daily sperm production (DSP) was 9% and 30% greater (P less than .01) for medium-energy diet bulls in 1980 (8.2 X 10(9) vs 7.5 X 10(9)) and 1981 (8.0 X 10(9) vs 6.2 X 10(9)), respectively, compared with high-energy diet bulls. The effect (P less than .01) of breed on DSP was attributed to breed differences in paired testes weight.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
Reproductive traits and preweaning growth of progeny from young Hereford, Red Poll, Hereford X Red Poll, Red Poll X Hereford, Angus X Hereford, Angus X Charolais, Brahman X Hereford and Brahman X Angus dams were evaluated. First-calf heifers were mated with Red Angus bulls; Santa Gertrudis sires were used for each cow's second and third breeding season. Herefords, Red Polls and Hereford-Red Poll crosses were below average in percentage of calves weaned, whereas Angus-sired and Brahman-sired dams exceeded the overall mean. Angus X Charolais (P less than .10), Brahman X Hereford (P less than .01) and Brahman X Angus (P less than .10) dams weaned a higher percentage of calves than straightbred Herefords. None of these breed types differed from young Angus X Hereford females in reproductive performance. Angus X Charolais calves ranked highest in 180-d calf weight, exceeding progeny from both Hereford (P less than .01) and Angus X Hereford (P less than .10) dams. Brahman X Hereford dams weaned heavier (P less than .05) calves than Herefords, but their progeny did not differ at weaning from those reared by Angus X Herefords. Calves from Brahman X Angus dams weighed 12.7 kg less (P less than .01) than Angus X Hereford progeny. Analysis of the Hereford-Red Poll diallel showed evidence of (P less than .10) maternal heterosis in 180-d calf weight.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Twelve 3/4 Angus (Angus) and 12 Wagyu-cross (1/2 Wagyu x 1/2 Angus) (Wagyu) heifers were weaned at 180 d of age and grazed on endophyte-infected tall fescue for 16 mo before entering the feedlot as 2-yr-olds. Twelve 3/4 Angus heifer calves and 12 Wagyu-cross heifer calves from the following year's calf crop were weaned at 142 +/- 4.1 d of age, immediately adjusted to an 80% concentrate diet, and finished as calves. All heifers were fed a common finishing diet until an estimated 50% of their respective group would grade USDA low Prime or better based on ultrasound predictions. Ultrasound measurements of s.c. and i.m. fat depots were recorded at 60-d intervals throughout the finishing period. Heifers finished as calves had higher (P = 0.02) marbling scores at any given fat thickness and gained more efficiently (P < or = 0.01) at any given marbling score than heifers finished as 2-yr-olds. Gain:feed decreased quadratically (P < or = 0.05) as 12th-rib fat thickness increased for Angus and Wagyu heifers. Gain:feed decreased linearly (P < or = 0.01) for Wagyu calves and quadratically (P < or = 0.01) for Angus calves as 12th-rib fat thickness increased. However, these differences in slope were not different (P = 0.34) as a result of breed among heifers finished as calves. Marbling score increased linearly (P < or = 0.01) as 12th-rib fat thickness increased for Angus and Wagyu heifers finished as 2-yrolds or as calves. However, Wagyu heifers, regardless of age at feedlot entry, had a higher marbling score (P < or = 0.05) at any given 12th-rib fat thickness than Angus heifers. Finishing early-weaned heifers as calves as opposed to 2-yr-olds results in i.m. fat deposition during a period of more efficient growth. Additionally, including Wagyu genetics into the breeding of early-weaned heifers finished as calves or as 2-yr-olds results in higher marbling scores at any 12th-rib fat thickness.  相似文献   

11.
Blood levels of calcitonin (CT), calcium (Ca), inorg. phosphate (P) and alkaline phosphatase (ALP) in 27 bulls of Swedish Red and White Breed (SRB) and 21 Swedish Friesian Breed (SLB) were studied. There was a significant lowering of Ca, P, ALP and CT with increasing age. The fact that the osteopetrotic syndrome is increasing with age in bulls and that the CT level in blood is decreasing with age does not support the idea that an increased CT discharge could be responsible for the osteopetrotic syndrome in bulls.  相似文献   

12.
Mature Hereford cows (766) were mated to 97 sires from seven breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin, and Belgian Blue), resulting in 1,215 calves born over 4 yr (1994 to 1997). These cattle comprised Australia's 'Southern Crossbreeding Project." Heifers were slaughtered at an average of 16 mo with hot standard carcass weight of 219 kg and 9 mm fat over the rump. Steers were slaughtered at an average of 23 mo with carcass weight of 319 kg and 13 mm fat over the rump. Meat and fat samples were taken from the carcass on the day after slaughter for subsequent laboratory analysis of i.m. fat content and fatty acid composition. Data were analyzed using uni- and bivariate animal models containing fixed effects of cohort, management group, birth month, and sire breed. March-born calves had fat with a 0.5 degrees C lower melting point, 0.6% higher total monounsaturated fatty acids, and 0.7% higher fatty acid desaturation index than calves born in April. Steers born in 1997 were the only cohort finished on pasture, and they had much more yellow fat than the other cohorts. Four heavy breed crosses (Angus, South Devon, Limousin, and Belgian Blue) averaged 284 kg carcass weight, followed by purebred Hereford (268 kg), Wagyu (244 kg) and Jersey (236 kg). Angus had the greatest fat depth (14.3 mm), ahead of Hereford and Wagyu (11.9 mm), Jersey (10.7 mm), South Devon and Limousin (9.9 mm) and Belgian Blue (8.0 mm). Jersey, Wagyu, and Angus had themost i.m. fat (4.6%), followed by Hereford and South Devon (3.8%), and Limousin and Belgian Blue (3.1%). The highly marbled Jersey and Wagyu had softer fat (6% lower fat melting point) than the other breeds. Angus were more highly marbled, similar to Jersey and Wagyu, but had harder fat similar to the leaner breeds. Heritabilities for all traits were low to moderate (16 to 36%). Genetic correlations between fatty add composition and carcass traits were not significant, indicating little evidence of antagonisms between traits that would prevent genetic progress in both production and quality.  相似文献   

13.
Yearling bulls (n = 3,071) located at 18 stations in Missouri, Nebraska, Virginia, and Wisconsin were measured for pelvic area, in addition to standard performance traits. Linear adjustments for age and weight were determined using covariate regression analyses. Only bulls that were 300 to 452 d of age, 325 to 640 kg, and were in consignments offering more than nine bulls per breed were included in the analyses. Because the subsets of Angus, Polled Hereford, and Simmental bulls had large numbers of observations (817, 271, and 449, respectively), individual adjustment coefficients were determined for each breed. Angus, Polled Hereford, and Simmental bulls had pelvic area adjustment regressions on age of .20, .32, and .20 cm2/d, respectively, and regressions on body weight of .15, .22, and .18 cm2/kg, respectively. Homogeneous linear responses of all breeds (11 breeds including Angus, Polled Hereford, and Simmental) were combined to form all-breed coefficients for age and weight adjustments, which were .21 cm2/d and .15 cm2/kg, respectively. Weight or age adjustments can be used to compare contemporaries for relative pelvic area differences, but both should not be used on the same bull. Although many factors contribute to dystocia, high priority should be given to identifying sires of replacement heifers of low to moderate birth weight genotype and above average pelvic area genotype.  相似文献   

14.
Angus and Wagyu steers consuming high-roughage diets exhibit large differences in adipose tissue fatty acid composition, but there are no differences in terminal measures of stearoyl-CoA desaturase (SCD) activity or gene expression. Also, adipose tissue lipids of cattle fed corn-based diets have greater MUFA:SFA ratios than cattle fed hay-based diets. We hypothesized that any changes in SCD gene expression and activity would precede similar changes in adipose tissue lipogenesis between short- and long-fed endpoints. Furthermore, changes in SCD activity and gene expression between production endpoints would differ between corn- and hay-fed steers and between Wagyu and Angus steers. Angus (n = 8) and Wagyu (n = 8) steers were fed a corn-based diet for 8 mo (short-fed; 16 mo of age) or 16 mo (long-fed; 24 mo of age), whereas another group of Angus (n = 8) and Wagyu (n = 8) steers was fed a hay-based diet for 12 mo (short-fed; 20 mo of age) or 20 mo (long-fed; 28 mo of age) to match the end point BW of the corn-fed steers. Acetate incorporation into lipids in vitro was greater (P < 0.01) in corn-fed steers than in hay-fed steers and tended (P = 0.06) to be greater in Wagyu than in Angus s.c. adipose tissue because the rate in Wagyu was twice that of Angus adipose tissue in the corn-fed, short-fed steers. There were diet x end point interactions for lipogenesis in i.m. and s.c. adipose tissues (both P < 0.01) because lipogenesis was 60 to 90% lower in the long-fed cattle than in short-fed cattle fed the corn-based diet. The greatest SCD enzyme activity in Angus s.c. adipose tissue was observed at 24 mo of age (corn-based diet), but activity in Wagyu adipose tissue was greatest at 28 mo of age (hay-based diet; breed x diet x end point interaction, P = 0.08). For short- vs. long-fed endpoints in Angus, s.c. adipose tissue SCD activity was less (hay diet) or the same (corn diet). Conversely, SCD gene expression was greatest in long-fed Wagyu steers fed the hay- or corn-based diets (breed x end point interaction; P < 0.01). Contrary to our hypotheses, SCD activity increased over time, whereas lipogenesis from acetate decreased. However, the developmental pattern of SCD gene expression and activity differed markedly between hay-fed Angus and Wagyu adipose tissues, which may explain the differences in the MUFA:SFA ratios observed in adipose tissues from these cattle.  相似文献   

15.
Mature dams representing Hereford, Red Poll, F1 Hereford x Red Poll, F1 Red Poll x Hereford, F1 Angus x Hereford, F1 Angus x Charolais, F1 Brahman x Hereford and F1 Brahman x Angus breed types were evaluated. All cows were bred to Limousin sires to produce two-way or three-way-cross progeny. Mature Brahman x Hereford dams produced a higher (P less than .05) percentage of live calves than Herefords, but dam breed differences in percentage of calves weaned relative to the number of cows exposed for mating were not statistically significant. Progeny of Angus x Charolais and Red Poll dams were outstanding in weaning weight, but Hereford and Brahman-cross calves were below average. Planned comparisons showed that Angus x Charolais calves were heavier (P less than .01) at weaning than Hereford (23.0 +/- 3.8 kg) or Angus x Hereford (9.6 +/- 3.2 kg) progeny. Mature Angus x Hereford mothers weaned heavier calves than did Brahman x Herefords (7.4 +/- 3.2 kg, P less than .05) or Brahman x Angus (10.9 +/- 3.0 kg, P less than .01). Analysis of the Hereford-Red Poll diallel showed evidence of maternal heterosis in calf weaning weight (4.0 +/- 2.6 kg, P less than .05), but there was no difference in the percentage of calves weaned by crossbred vs straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
Birth, weaning, feedlot and carcass traits were evaluated on 1,181 calves sired by Charolais and Limousin bulls out of eight crossbred dam groups (Hereford X Angus, Angus X Hereford, Simmental X Angus, Simmental X Hereford, Brown Swiss X Angus, Brown Swiss X Hereford, Jersey X Angus, Jersey X Hereford). Calves were born in the spring over a 4-yr period during which dams ranged from 3 to 8 yr of age. Charolais-cross calves were 2.7 kg heavier (P less than .01) at birth and had a 9.9% higher (P less than .01) incidence of difficult calvings and 4.6% greater (P less than .05) preweaning death loss than did Limousin crosses. Charolais-sired calves out-gained Limousin-sired calves by 31 g/d (P less than .01) from birth to weaning and were 9 kg heavier (P less than .01) at weaning. After weaning, calves were self-fed a finishing diet and slaughtered as each animal attained an estimated carcass grade of low Choice. Charolais-cross calves gained 60 g/d faster (P less than .01) than Limousin crosses, were fed 6.8 fewer d and were 17.3 kg heavier (P less than .01) at slaughter. Feed efficiency was similar for both sire breeds. On a grade-equivalent basis, Charolais crosses produced 7 kg heavier (P less than .01) carcass and had 22 g more carcass weight per day of age (P less than .01). Charolais crosses had slightly less internal and external fat. Dressing percentage was higher for Limousin cross calves (64.6 vs 63.9%, P less than .01). Longissimus muscle area and carcass cutability were similar for crosses of both sire breeds.  相似文献   

17.
Knowledge of the relationships between absolute growth rate (AGR), relative growth rate (RGR) and feed conversion (FCONV) of bulls in postweaning feedlot performance tests can give cattle producers important information for selecting superior sires. Weight gain and FCONV data that were collected during 16 yr were analyzed from 393 Angus and 340 Hereford bulls by 26 and 27 sires, respectively, that were individually fed in 140-d tests. Sire variance and covariance components were used to obtain heritability (h2) estimates for AGR, RGR and FCONV and the genetic correlations (rg) and phenotypic correlations (rp) among these traits. Respective mean AGR, RGR and FCONV were 1.27 +/- .14 kg/d, .4378 +/- .0395%/d and 7.32 +/- .58 kg/kg for the Angus and 1.28 +/- .12 kg/d, .4552 +/- .0388%/d and 6.56 +/- .46 kg/kg for the Hereford bulls. Estimates of h2 were similar for AGR and RGR in both Angus (.36 +/- .11 and .22 +/- .09) and Hereford (.33 +/- .11 and .20 +/- .09) bulls. The h2 estimates for FCONV were .14 +/- .07 for Angus and .13 +/- .08 for Herefords. For the Angus and Hereford bulls, respectively, rg were .86 +/- .09 and .86 +/- .13 between AGR and RGR, -.84 +/- .38 and -.74 +/- .49 between AGR and FCONV and -.84 +/- .49 and -.61 +/- .64 between RGR and FCONV. The rp were .80 +/- .03 and .68 +/- .04 between AGR and RGR, -.58 +/- .05 and -.51 +/- .05 between AGR and FCONV and -.71 +/- .04 and -.73 +/- .04 between RGR and FCONV for the Angus and Hereford bulls, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
The objective of this study was to evaluate the growth curves of females to determine if mature size and relative rates of maturation among breeds differed. Body weight and hip height data were fitted to the nonlinear function BW = f(age) = A - Be(k×age), where A is an estimate of mature BW and k determines the rate that BW or height moves from B to A. Cows represented progeny from 28 Hereford, 38 Angus, 25 Belgian Blue, 34 Brahman, 8 Boran, and 9 Tuli sires. Bulls from these breeds were mated by AI to Angus, Hereford, and MARC III composite (1/4 Angus, 1/4 Hereford, 1/4 Red Poll, and 1/4 Pinzgauer) cows to produce calves in 1992, 1993, and 1994. These matings resulted in 516 mature cows whose growth curves were subsequently evaluated. Hereford-sired cows tended to have heavier mature BW, as estimated by parameter A, than Angus- (P=0.09) and Brahman-sired cows (P=0.06), and were heavier than the other breeds (P < 0.001). Angus-sired cows were heavier than Boran- (P < 0.001) and Tuli-sired cows (P < 0.001), and tended to be heavier than Belgian Blue-sired cows (P=0.097). Angus-sired cows did not differ from Brahman-sired cows (P=0.94). Brahman-sired cows had a heavier mature BW than Boran- (P < 0.001), Tuli- (P < 0.001), and Belgian Blue-sired cows (P < 0.04). Angus-sired cows matured faster (k) than cows sired by Hereford (P=0.03), Brahman (P < 0.001), Boran (P=0.03), and Tuli (P < 0.001) sires, but did not differ from Belgian Blue-sired (P=0.13) cows. Brahman-sired cows took longer to mature than Boran- (P=0.03) or Belgian Blue-sired cows (P=0.003). Belgian Blue-sired cows were faster maturing than Tuli-sired cows (P=0.02). Brahman-sired cows had reached a greater proportion of their mature BW at puberty than had Hereford- (P < 0.001), Tuli- (P=0.003), and Belgian Blue-sired cows (P=0.001). Boran-sired cows tended to have reached a greater proportion of their mature BW at puberty than had Angus-sired cows (P=0.09), and had reached a greater proportion of their mature BW at puberty than had Hereford- (P < 0.001), Tuli- (P < 0.001), and Belgian Blue-sired cows (P < 0.001). Within species of cattle, the relative range in proportion of mature BW at puberty (Bos taurus 0.56 through 0.58, and Bos indicus 0.60) was highly conserved, suggesting that proportion of mature BW is a more robust predictor of age at puberty across breeds than is absolute weight or age.  相似文献   

19.
Cows (n = 116) sired by Angus, Gray Brahman, Gir, Indu-Brazil, Nellore, and Red Brahman bulls and from Hereford dams were evaluated (when bred to the same breed of bull) for reproductive performance and cow weight and height and their calves (n = 1,161) were evaluated for birth and weaning weight in central Texas (temperate winters and subtropical summers). Cows were born from 1982 to 1985 and their calves were born from 1985 to 1999. Crossbred cows sired by Angus had a higher (P < 0.10) occurrence of calving difficulty than Gir, Indu-Brazil, Nellore, and Red Brahman crossbreds. Calves from Gir crossbreds had lighter (P < 0.10) birth weight (34.8 kg) than calves from Angus and Red Brahman crossbreds (39.4 and 37.2 kg). Calves from Angus crossbreds cows had lighter (P < 0.001) weaning weight (227.0 kg) than calves from Bos indicus crossbreds. Cows sired by Angus were lighter (P < 0.10) as mature cows (520.69 kg) than Gray Brahman, Indu-Brazil, and Red Brahman crossbreds (585.6, 571.9, and 577.6 kg, respectively). They also had smaller (P < 0.05) hip height (124.7 cm) than Bos indicus crossbreds. Mature cows sired by Indu-Brazil had greater (P < 0.05) hip height (138.3 cm) than Gir crossbreds (133.8 cm). Differences among sire breeds were noted within cow age categories (2 through 14 yr of age) for pregnancy rate, calf crop born, calf survival rate (as a trait of cow), and calf crop weaned. Angus and Indu-Brazil crossbred cows were lower (P < or = 0.10) than Gir and Nellore crossbreds for pregnancy rate, calf crop born, and(or) calf crop weaned at some, but not all, ages. Indu-Brazil crossbreds had a lower (P < or = 0.10) calf survival rate than most other breed groups at ages 11 to 14 yr. The results of this study indicate that Nellore and Gir crossbreds, but not Indu-Brazil, could perform as well or better than breeds traditionally used in cross-breeding programs of U.S. cow-calf production.  相似文献   

20.
We determined changes in insulin, glucose, free fatty acids (FFA), growth hormone (GH), insulin-like growth factor I (IGF-I) and LH before puberty in Angus, Braford, Charolais, and Simmental heifers. Our primary objective was to identify metabolites and metabolic hormones that serve as metabolic cues for onset of puberty. Angus (n = 12). Braford (n = 7), Charolais (n = 9), and Simmental (n = 7) heifers were assigned at weaning (289 +/- 25 d of age; 264 +/- 23 kg) to open-sided pens with slotted floors, and they were fed a corn silage-concentrate diet formulated to provide gains of .91 kg/d. Puberty was defined as the 1st d (d 0) that serum progesterone (determined in blood samples collected at weekly intervals) exceeded 1 ng/ml. Blood samples were collected before and after feeding at 15-min intervals for 8 h at 21-d intervals before puberty in a subsample of heifers (at least five per breed). Angus and Simmental heifers weighed less and were younger (P less than .05) at puberty than Charolais and Braford heifers. Serum FFA before feeding and frequency of LH release increased (P less than .05) from d-40 +/- 3 to d-17 +/- 3 in all breeds. Conversely, concentrations of insulin were greater (P less than .05) at -40 than at -17 d from puberty in Angus, but not in Braford, Charolais, or Simmental heifers. Frequency of GH release was greater at d -40 than at d -17 in Angus heifers; however, in Braford and Charolais heifers frequency of GH release was greater at d -17 than at d -40. Concentrations of IGF-I (measured every 2 wk) increased linearly (P less than .07) from d -56 to 0 from puberty in Angus but not in other breeds. In conclusion, frequency of LH release and concentrations of FFA increased before puberty in all breeds; however, consistent changes in other metabolites and hormones were observed only in Angus heifers.  相似文献   

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