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1.
Angus, Boran and Red Poll sires were mated to Ankole, Boran and small East African Zebu (Zebu) females to produce the cows characterized in this study, which produced calves by Friesian, Brown Swiss, Simmental, Boran and Red Poll sires. Individual traits included cow parturition weight, cow weight at weaning, cow mean weight and cow weight change from parturition to weaning; maternal traits included calf crop born percentage, preweaning viability percentage, overall viability percentage, birth weight, weaning weight, weight at 12, 18 and 24 mo and calf weight weaned per cow exposed to breeding (productivity index). Cows by Angus and Red Poll sires significantly exceeded cows by Boran sires (all cows in this comparison had Ankole and Zebu dams) in weaning weight of progeny and in cow weight at parturition and at weaning. Cows by Red Poll sires significantly exceeded cows by Boran sires in birth weight of progeny. Progeny of cows by Boran sires significantly exceeded progeny of cows by Angus and Red Poll sires in 24-mo weight. Cows by Angus and Red Poll sires did not differ (P greater than .05) in any of the traits analyzed. Cows with Ankole and Boran dams significantly exceeded cows with Zebu dams (all cows in this comparison had Angus and Red Poll sires) in progeny weight at birth, 18 mo and 24 mo and in cow weight at parturition and at weaning. Cows with Boran dams significantly exceeded cows with Zebu dams in weaning and 12-mo weight of progeny and significantly exceeded cows with Ankole dams in weaning weight of progeny. The significantly heavier weaning weight and significantly lighter 24-mo weight of the 3/4 Bos taurus progeny of cows with Angus and Red Poll sires relative to the 1/2 Bos taurus progeny of cows with Boran sires suggest that cattle that are 1/2 Bos taurus breed composition have greater general adaptation than cattle with 3/4 Bos taurus breed composition in the postweaning nutritive and climatic environment under which this experiment was conducted. Significantly heavier weights of Angus and Red Poll crossbred cows relative to Boran crossbred cows (all breeds crossed on Ankole and Zebu cows) indicate that the two Bos taurus breeds exceed the Boran (Bos indicus) breed in additive direct genetic effects for size when they have general adaptation to the environment. 相似文献
2.
Data were analyzed to estimate the effects of heterosis and breed on a series of maternal and individual traits. Crossbred cows were Boran X Ankole and Boran X Zebu; straight-bred cows were Ankole, Boran and Small East African Zebu (Zebu). Cows of all breed groups were mated to Friesian, Brown Swiss and Simmental sires to produce crossbred progeny. While not generally significant, the average effects of heterosis of both crosses for the traits analyzed were: calf crop born, 7.0%; preweaning viability, 7.2%; overall viability, 7.3%; birth weight, 6.0%; weaning weight, 5.4%; 12-mo weight, 4.2%; 18-mo weight, 3.7%; 24-mo weight, 3.6%; calf weight weaned per cow exposed to breeding (cow productivity index), 24.5%; cow parturition weight, 3.5%; cow weaning weight, 4.2% and cow mean weight, 4.0%. Boran cows weaned 31.8 kg (48.0%) more (P less than .05) calf weight per cow exposed to breeding than Ankole cows. Boran cows were generally superior to Zebu cows in progeny weights at all ages (P less than .01). Boran cows weaned 34.5 kg (54.3%) more (P less than .05) calf weight per cow exposed to breeding than Zebu cows. Boran cows weighed an average of 70.8 kg more (P less than .01) than Zebu cows. Although progeny of Ankole dams were heavier (P less than .05) than the progeny of Zebu dams at all ages, the two breeds did not differ (P greater than .05) in calf weight weaned per cow exposed to breeding. Mean weight of Ankole cows was 75.8 kg heavier (P less than .01) than mean weight of Zebu cows. 相似文献
3.
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
4.
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
5.
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
6.
R E Sacco J F Baker T C Cartwright C R Long J O Sanders 《Journal of animal science》1989,67(8):1972-1979
Records of 2,449 births and 2,120 weanings of terminal-cross calves were used to characterize maternal productivity of first- and second-generation cows from a diallel of Angus, Brahman, Hereford, Holstein and Jersey when mated to third-breed sires. Third- and later-parity cows were randomly assigned after each parturition to Charolais and Red Poll bulls in multiple-sire pastures. Calves were weaned at approximately 7 mo of age; males were not castrated. A mixed model was assumed for data analysis. Effects included in the model were breed-type of dam, cow within breed-type of dam (random), breed of sire of calf, season of record, year of record, age of dam group, sex of calf and age of calf (covariate). Age of dam groups were 4- and 5-yr-olds, 6- and 7-yr-olds, 8-, 9- and 10-yr-olds, and those greater than 10 yr of age. Dependent variables were calf weight, shoulder width and hip width at birth, weaning weight, weaning height and survival to weaning. Holstein and Holstein crosses tended to produce the largest calves at birth and weaning. Among straightbred dams, the smallest calves were born to Brahman, whereas Hereford weaned the smallest calves. Brahman-Jersey dams produced the smallest calves at birth among crossbreds; Angus-Hereford cows weaned the smallest calves. Average maternal heterosis estimates for birth weight were small and non-significant. Calves of F1 crossbred dams were 17.4 kg heavier (P less than .01) and 1.70 cm taller (P less than .01) at weaning than calves of first-generation straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
A deterministic model was developed that accounted for all biological inputs and outputs for a theoretical herd of F1 females at age equilibrium mated to produce three-way terminal-cross calves and for the required proportion of straightbred cows needed to produce replacements. Two Bos indicus x Bos taurus vs two Bos taurus x Bos taurus types of crossbred cows were compared in the production environment of south-central Nebraska. The four types of F1 females were from Hereford (H) or Angus (A) dams and by H or A (HA), Pinzgauer (Pz), Brahman (Bm), or Sahiwal (Sw) sires. The crossbred females were assumed mated to Red Poll (R) sires for their first calving and to Simmental (S) sires thereafter. Two evaluations of efficiency for each of the four breeding systems were total cow and calf feed energy input 1) per unit of only weaned calf weight output (CALFEFF, Mcal/kg) and 2) per unit of weaned calf plus .55 x cull cow weight output (TVALEFF, Mcal/kg). Results for a terminal age of 7 yr in systems using HA, Pz, Bm, and Sw crossbred cows, respectively, were 64.9, 64.5, 60.9, and 59.3 Mcal/kg for CALFEFF and 45.7, 46.4, 44.1, and 43.7 Mcal/kg for TVALEFF. Changing terminal age to 11 yr reduced CALFEFF about 6% but increased TVALEFF about 7%, because total inputs increased more than output value (10 vs 3%) from 7 to 11 yr terminal ages. These results suggest differences in efficiency among these breed crosses favoring the Bos indicus crossbred cows by over 4% in this particular environment. 相似文献
8.
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
9.
October pregnancy rate, calf survival to weaning, weaning age, weaning rate and actual kg of calf weaned/cow exposed were determined in a 4-yr study involving 880 matings of Angus (A), Hereford (H) and Charolais (C) sires to A, H, C and Brown Swiss (BS) dams. Cows were mated in single-sire herds for 45 or 60 d under pasture conditions; heifers were bred to produce their first calf at 3 yr of age. Pregnancy rate of lactating dams was 9.4% higher (P less than .01) than for non-lactating dams. Pregnancy rates for straightbred matings were 87.5%, 80.6% and 75.4%, respectively, for A, H and C groups (P less than .05). No differences (P greater than .10) due to sire breed were found for any of the traits studied except for calf age at weaning. Calves from C sires were younger (P less than .01) at weaning than calves from H and A sires. Breed-of-dam differences (P less than .05 to P less than .01) were found for all traits studied except calf survival rate. All BS dams produced crossbred calves and had lower pregnancy and weaning rates (both P less than .01), calves were younger at weaning (P less than .05), had lower kg of calf weaned/cow exposed (P less than .05) than for beef-breed dams producing crossbred calves. Crossbred calves from BS dams were 4.9, 11.0 and 3.4 d younger (P less than .05 to P less than .01) at weaning, respectively, than crossbred calves from H, A and C dams.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
10.
Postpartum udder characteristics, aged mouth condition scores, and cow survival, longevity, and productivity were evaluated for 15 yr on F1 cows in central Texas (temperate winters and subtropical summers). The cows (n = 116) were progeny of Angus, Gray Brahman, Gir, Indu-Brazil, Nellore, and Red Brahman sires and Hereford dams. Crossbred cows sired by Nellore had smaller (P < 0.05) postpartum teat length than cows of all other crossbred groups and smaller (P < 0.10) postpartum teat diameter than Indu-Brazil and Red Brahman crossbreds. The Nellore crossbred cows had larger (P < 0.10) postpartum udder support scores (more well-supported udders) than Gir, Indu-Brazil, and Red Brahman crossbreds. As 14-yr-old cows, Angus crossbreds had lower (P < 0.05) mouth scores (indicative of one or more missing incisors) than Bos indicus crossbreds. Under actual and artificial (records were removed) culling procedures, Nellore crossbreds had the highest cow survival to age 14 and the highest longevity. Indu-Brazil crossbreds tended to be the lowest for both survival and longevity. Curves were fitted by nonlinear regression procedures to the adjusted frequencies of cows remaining at each age; scale and shape parameters were estimated and compared for the different breed groups. Breed group cow survival rates, calf crop weaned, and calf weaning weights were used 1) to construct population projection and production matrices for each breed group and 2) to generate breed group vectors containing projected age distributions and production information. Cows sired by Nellore and Gir were projected to require the fewest purebred cows to generate replacement heifers and to have the most calves and the largest total calf weight sold per year. 相似文献
11.
Yield, butterfat, protein, lactose and solids-not-fat of milk from mature dams (n = 128) representing eight Bos taurus and Bos indicus X Bos taurus breed types were evaluated approximately 60, 105 and 150 d postpartum. Breed type was a significant source of variation in milk yield at each stage of lactation. Average 24-h milk yields (kg) were: Hereford, 7.3; Red Poll, 9.1; Hereford X Red Poll, 9.1; Red Poll X Hereford, 9.1; Angus X Hereford, 8.6; Angus X Charolais, 9.3; Brahman X Hereford, 7.3 and Brahman X Angus, 8.3. Daily yields of Brahman X Angus dams increased as lactation progressed, while production levels of other breed types remained approximately the same or declined. Hereford-Red Poll crosses showed significant heterosis in 24-h milk production and component yields at 150 d. Breed type effects also were significant for lactose yield throughout lactation. Sex of calf influenced (P less than .05) milk yield at 60 and 105 d postpartum and yield of protein and solids-not-fat at 105 d. Mastitis caused a reduction (P less than .01) in percentage of lactose but had no effect on milk yield. Residual correlations between yield traits and preweaning average daily gain were all positive and significant, with values ranging from .22 to .45. Breed type was a major source of variation in milk traits of beef-type Bos taurus and Bos indicus X Bos taurus dams. 相似文献
12.
The fourth through sixth parity of 5- to 10-yr-old cows were used to evaluate trade-offs involved with sires of large mature size vs medium mature size in a terminal sire crossbreeding program and to characterize five breeds and their crosses for their potential as dam lines. Charolais and Red Poll bulls, representing large (L) and medium (M) mature size, respectively, were mated to cows representing Angus (An), Brahman (Br), Hereford (He), Holstein (Ho) and Jersey (Je) and their crosses (reciprocals pooled). Cows were randomly assigned for mating to either an L or M bull for each breeding. Size of calf sire did not influence (P greater than .10) the subsequent calving interval of cows. Calving intervals for the straightbred (SB) dairy breeds (Ho and Je) were longer than for SB An and He, but the difference did not exist among the respective crossbred (CB) cows. As a group, Br crosses had shorter intervals than the other CB groups. Crossbred cows exhibited intervals that were 16 d shorter (P less than .05) than SB. Calves sired by L bulls were larger (P less than .01) and faster gaining (P less than .01) for all measures of size and growth studied, but exhibited lower (P less than .01) survival rates to weaning than M-sired calves. Calves of CB dams were 1.5 kg heavier (P less than .01) at birth than calves of SB dams and slightly greater (nonsignificant) hip and shoulder measurements were observed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
13.
C M Bailey 《Journal of animal science》1991,69(6):2379-2386
Females 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 from birth until 10 yr of age. Of 308 females born alive, 35.7% died or were culled because of injury, serious illness, or reproductive failure. Breed types differed (P less than .01) in total number of mating seasons per cow and total number of progeny born and weaned. Values for lifetime total number of calves weaned were as follows: Hereford, 4.54; Red Poll, 5.45; Hereford x Red Poll, 4.45; Red Poll x Hereford, 5.49; Angus x Hereford, 5.98; Angus x Charolais, 5.57; Brahman x Hereford, 6.96; and Brahman x Angus, 6.22. Brahman crosses (P less than .01) and Angus x Charolais (P less than .10) exceeded Hereford dams in lifetime total number of calves weaned but did not differ from Angus x Herefords. Analysis of the Hereford-Red Poll diallel showed no evidence of heterosis in life span traits. Results indicate that breed type was a major source of variation in reproductive life span of beef-type females. F1 Bos indicus crosses and Angus x Herefords were outstanding in longevity. 相似文献
14.
Preweaning efficiency for mature cows of breed crosses from tropically adapted Bos indicus and Bos taurus and unadapted Bos taurus breeds 总被引：1，自引：0，他引：1
Production data were collected on mature cows produced by mating Angus and Hereford (pooled AH), Brahman (Bh) and Boran (Br), and Tuli, a tropically adapted Bos taurus, sires by AI or natural service to Angus and Hereford cows. These cows were mated to Charolais bulls for the purpose of this study. Within each sire breed of cow, cows were assigned randomly to one of three feeding rates, 49 or 76 g of DMI/ BW0.75 or ad libitum (10 to 12 cows/feeding rate group), with weekly individual animal feed consumption recorded. Lactation yields were recorded via the weigh-suckle-weigh protocol at approximately 14, 28, 56, 84, 112, 140, 168, and 196 d postpartum for each cow/calf pair. Means for milk yield at peak lactation, total milk yields, calf birth weight, age-adjusted weaning weights, preweaning daily gain, and feed efficiency were estimated. Peak yield (kg/d) for Bh (10.3 +/- 0.36) was greater (P < 0.05) than for Tuli (9.0 +/- 0.31). Total yield (kg, 212 d) for Bh (1802 +/- 68) was greater (P < 0.05) than for Tuli (1532 +/- 59). Birth weight of AH (44 +/- 0.9) was heavier than for Bh and Br (P < 0.05). Preweaning daily calf gain (g/d) and adjusted weaning weight (kg) of Bh (813 +/- 28, 212 +/- 6.1) and Br (766 +/- 24, 202 +/- 5.1) differed (P < 0.05) from AH (589 +/- 24, 169 +/- 5.2) and Tuli (634 +/- 24, 176 +/- 5.3). Efficiency estimates (grams of adjusted weaning weight/kilograms DMI of the cow) for Bh (88 +/- 2.5) and Br (85 +/- 2.1) exceeded (P < 0.05) those for Tuli (74 +/- 2.1) and AH (73 +/- 2.1). Bos indicus breed crosses exhibited greater peak and total yield, lower birth weight, greater daily gain and adjusted weaning weight, and higher feed efficiency than did Bos taurus breed crosses (P < 0.05). Total yield, daily gain, adjusted weaning weight, and feed efficiency were higher (P < 0.05) for cows sired by bulls from tropically adapted breeds, and the peak yield was less (P < 0.10). Tuli exhibited lower total yield and birth weight than did Angus/Hereford (P < 0.05). The efficiency of crossbred Tuli cows did not differ from Angus/Hereford F1 females, but neither equaled the efficiency of crossbred cows produced using Bos indicus breeds. 相似文献
15.
Productivity of 3-, 4-, and 5-yr-old crossbred cows containing various proportions (0, 1/4, or 1/2) of Brahman breeding out of Angus or Hereford dams was evaluated using 489 spring-calving and 427 fall-calving records collected over a 4-yr period. Cows were bred to Limousin sires for the first 3 yr and to Limousin and Salers sires the 4th yr. Interactions between crossbred cow group and season of calving were not significant. Percentage of cows exposed to breeding that weaned a calf increased (P less than .01) as proportion Brahman breeding increased, was higher (P less than .01) for cows out of Angus dams than for cows out of Hereford dams, and was higher (P less than .01) for spring-calving cows. As the proportion Brahman increased, the percentage requiring assistance at birth decreased, and cows out of Angus dams required less (P less than .05) assistance than those out of Hereford dams. Preweaning ADG, adjusted weaning weight, weaning conformation, weaning condition, and adjusted weaning hip height increased a proportion Brahman breeding increased. Spring-born calves gained .12 kg/d faster (P less than .01) than fall-born calves. However, weight at weaning was similar for the two groups; spring-born calves were weaned at an average age of 205 d, and fall-born calves were weaned at an average age of 240 d. Fall-calving cows were heavier (P less than .05) than spring-calving cows, and 0 and 1/2 Brahman cows were heavier (P less than .01) than 1/4 Brahman cows. These data indicate that Brahman-cross dams can be used to improve reproductive rate and increase preweaning growth rate, and thus weaning weight.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
16.
Crossbred progeny from females, 3 yr old and older, representing Brown Swiss (B), Red Poll (R), Hereford (H) and Angus (A) maternal grandsires and maternal granddams in a diallel crossing experiment were evaluated to estimate breed mean maternal heterosis (mean hMi) for each breed, maternal heterosis for specific breed cross females (hMij), average maternal heterosis for all crosses (mean hM) and breed grandmaternal effects (gM'i) for preweaning calf traits. Estimates of mean hM were significant for birth date and weight, 200-d weight and 200-d weight/cow exposed. Even though calves with crossbred dams weighed more at birth, they did not differ from calves with straightbred dams in frequency of calving assistance. The estimates of hMij were similar for most crosses and most traits, except 200-d weight and 200-d weight/cow exposed. The largest heterotic advantage was exhibited by progeny of BH reciprocal cross females, which exceeded crossbred progeny from BB and HH females for 200-d weight/cow exposed by 35.9 kg. The smallest heterotic effect was exhibited by crossbred progeny of RA reciprocal cross females. Progeny with R maternal granddams exhibited a higher (P less than .05) live calf born and weaned percentage than progeny with H maternal granddams. Progeny with B maternal granddams were born later (P less than .05) in the calving season than progeny with R maternal granddams. Progeny with A maternal granddams exhibited a lower frequency of calving assistance than progeny with H maternal granddams, and progeny with H maternal granddams were heavier (P less than .05) at 200 d than progeny with R maternal granddams. There was a tendency for estimates of breed grandmaternal effects (gMi) to exhibit an inverse relationship with estimates of breed maternal effects (gMi). 相似文献
17.
Nonpregnant F1 crossbred cows, progeny of either Hereford (H) or Angus (A) dams and sired by Brahman (Bm), Sahiwal (Sw), Pinzgauer (Pz), H, or A sires, were fed to maintain initial weight while rearing Charolais (C)-sired progeny for a period of 126 d in drylot commencing at about 48 d postpartum. Cow-calf pairs were assigned to equalize cow age, calf sex, and breed of cow's dam among three replicate pens of approximately 12 pairs each. Cows and calves were weighed every 2 wk and feed intake was adjusted to minimize change in cow weight. Metabolizable energy (ME) consumption for zero cow weight change was estimated by regression. Milk production was estimated by weight-suckle-weigh at 58, 85, 125, and 170 d of lactation. Calf gain (GAIN, kg) relative to cow weight (CWT1, kg) was higher (P less than .01) for calves from Bm-X (139.5/585) and Sw-X (132.2/534) than for calves from Pz-X (127.2/552) and HA-X (116.9/547) cows. Estimated mean daily production of milk was 7.40, 7.15, 7.28, and 6.37 kg for the Bm-X, Sw-X, Pz-X, and HA-X, respectively. Total cow ME intake (TMEcow) for breed groups ranked (P less than .05) with cow size and milk production, and calf creep-feed intake (FMEcalf) was inversely related to estimated milk intake. Proportion of total feed ME (TMEcow+calf) consumed by calves was higher (P less than .05) for HA-X cows (18%) than for the others (14%). Total efficiency of calf gain in weight (GAIN/TMEcow+calf) was 11% greater (P less than .05) for crossbred cows of Bos indicus X Bos taurus (Bm-X, Sw-X) than for Bos taurus X Bos taurus (Pz-X, HA-X) cows (35 vs 32 g/Mcal) in the 126-d lactation period. 相似文献
18.
Metabolizable energy for maintenance (MEm) was estimated using 123 mature cows of eight diverse breed groups. Cows in each breed group were allotted at random 1) to limit-feeding to approximate maintenance or 2) to ad libitum access to feed. The MEm values were calculated by regression of change in body energy on ME intake. The MEm values for 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 breed types were as follows: 145, 169, 148, 149, 144, 152, 139, and 143 kcal.kg-.75.d-1, respectively. Bos indicus-cross cows ranked lowest for MEm/kg.75. Angus x Hereford cows averaged highest in terms of grams of calf weaned per mature female exposed divided by yearly MEm requirement. Hereford x Red Poll reciprocal crosses on average required 640 kcal less total daily MEm per animal than Hereford and Red Poll straightbreds. 相似文献
19.
Gestation length, birth weight calving difficulty, calf mortality rate at birth, calf mortality rate from birth to weaning, preweaning calf growth rate and calf 200-d weight were evaluated in a biological type study in which four sire breeds were bred by AI to Hereford dams. Angus and Red Poll sires represented breeds of medium size, and Pinzgauer and Simmental sires represented large breeds. Angus and Pinzgauer represented breeds with medium milk production, and Red Poll and Simmental represented breeds with high milk production. Dams mated to large sire breeds had longer (P less than .01) gestation lengths (.95 d) and higher calving difficulty scores than dams mated to medium-sized sire breeds. Calves from large sire breeds had heavier birth weight (P less than .01) and 200-d wt (6.1 kg; P less than .01) than calves from medium-sized sire breeds. Calf death loss and ADG to weaning were similar (P greater than .10) for all breeds of sire. Calves from the higher milk level sire breeds exceeded the medium-milk breeds in birth weight (1.3 kg; P less than .01) but did not (P greater than .10) in other traits. Calves from the higher milk level sire breeds exceeded the medium-milk breeds in birth weight (1.3 kg; P less than .01) but not (P greater than .10) in other traits. Interaction between size and milk production of sire breed existed for gestation length, birth weight, ADG from birth to weaning and 200-d calf weight (P less than .01). In general, mature size of sire breed was a good indication of expected performance traits not easily influenced by environment. Not all differences, however, could be explained by size and milk production of the size breed. 相似文献
20.
Over six calf crops, 524 exposures of Angus cows to three sire breeds resulted in 432 weaned calves for an 82.4% calf crop. Least-squares means for weaning rate by sire breed were 81.8, 80.5 and 83.9% for Angus, Charolais and Holsteins, respectively. Sire breed effect was not significant for calving rate, calf mortality or overall weaning rate, but was significant for all growth traits from birth to 18 mo. Angus-sired calves were smallest at birth, grew at a slower rate and were lightest in weight at all ages. Charolais-sired calves were heaviest at all weigh periods and Holstein-sired calves were intermediate. Holstein-sired calves scored significantly lower for both grade and condition than did Angus- and Charolais-sired calves. Charolais-sired calves had the highest grade. Calving rate tended to be influenced by the effect of cow (P less than .10) and sire breed X year (P less than .001). Calving rate was highest for 3-yr-old and for 6- to 10-yr-old cows and was also 1.5 percentage units higher for crossbred matings. Cow productivity (kg of calf weaned/cow exposed) is a combined measure of fertility, calf survival and weaning weight. Although sire breed did not significantly affect cow productivity (P less than .20), actual values favored cows producing crossbred calves by 14 and 9 kg for Charolais and Holstein crosses, respectively. Likewise, weight differences at 18 mo favored these crosses by 50 and 32 kg for heifers and 72 and 62 kg for steers. Among the two crossbred types, Charolais X Angus heifers were 28 kg heavier (P less than .05) than Holstein X Angus heifers at 18 mo but the 10 kg difference in steers was not significant. The fact that the large sire breeds produced calves with heavier weaning weights without demonstrating significant increases in overall productivity points out the importance of high weaning rates. 相似文献