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1.
Data collected from 1993 to 2006 at the Animal Research Institute of Ghana was used to compare the performance of Sanga and Friesian-Sanga crossbred calves on natural pasture. Performance traits analyzed were birth weight (BWT), weaning weight adjusted to 210 days (WW7), preweaning average daily gain to 210 days (ADG 1), weight at 12 months adjusted to 365 days (W12), weight at 18 months adjusted to 540 days (W18) and postweaning average daily gain (ADG 2, from weaning to 540 days). Effects in the model describing these traits were breed, season, sex and first-order interactions between these effects. With the exception of heavier birth weight of Friesian-Sanga crossbred calves (19.98 kg vs. 19.18 kg), body weights of Sangas at weaning, 12 months and 18 months exceeded those of the Friesian-Sanga crossbred calves by 3.76 kg, 35.06 kg and 46.24 kg respectively. The Sangas were also superior in preweaning average daily gain (0.35 kg/day vs. 0.26 kg/day) and postweaning average daily gain (0.28 kg/day vs. 0.21 kg/day). There was a tendency of increasing weight difference between the two breeds with advancing age. It was suggested that improved nutrition such as supplementary feeding would be necessary for crossbreds to express their potential for growth.  相似文献   

2.
The objective of this study was to evaluate the body weights up to 18 months of age of 12 breed groups of Zebu (Z), Brown Swiss (BS) and Charolais heifers (CH), and their crosses under tropical conditions. A total of 1434 data on weaning weights adjusted to 240 days (WW8), average daily gain to 240 days (ADG8) and 1025 body weights adjusted to 550 days (BW18) and average postweaning daily gain (ADG18) of heifers born from 1981 to 1995 were used. Cows and calves remained together from birth to weaning and grazed on Guinea grass (Panicum maximum). Years of birth were grouped in three periods, because of the small numbers of observations per year (1981–85, 1986–90 and 1991–95). Similarly, months of birth were grouped in three seasons: dry (February to May), rainy (June to September) and windy and rainy (October to January). Ages of dams were classified in six groups (≤3, 4, 5, 6, 7 and ≥8 years). Breed groups were animals with 12.5%, 25.0%, 50.0%, 62.5%, 75.0% and 100% BS genes and 25.0%, 50.0%, 75.0% and 100% CH genes and also Z and undefined crossbred animals. Data were analysed using a fixed model that included effects of period, and season of birth, age of dam and breed group of heifer. Analyses of variance showed significant (p < 0.05) effects of period, season and breed group for all traits. However, parity was significant (p < 0.05) only for WW8 and ADG8. Interactions among main factors were not significant (p > 0.05). Z heifers gained the least weight to weaning but were similar to BS at 18 months of age. CH were heavier at 18 months of age than BS heifers, but not at weaning. Body weights at 18 months of age of 1/8 and 1/4 BS crossbred heifers were similar (p > 0.05) and lower than F1 (BS × Z) (p < 0.05); however, the later and higher grades of BS had the highest body weights at 18 months of age and were similar to CH and 1/4 CH × 3/4 Z heifers. Undefined crossbred heifers had better performance than the Z breed group. Environmental factors were important sources of variation for pre‐ and postweaning traits. Under the conditions of this study, crossbred heifers generally performed better than Z heifers up to 18 months of age.  相似文献   

3.
The Network Project on Sheep Improvement (NWPSI)–Madras Red field unit is a group breeding scheme involving 198 farmers’ flocks of Madras Red sheep in which selection for growth traits and rotation of rams have been practised for over two decades. Growth data collected from these flocks were used to evaluate the performance and understand the direct and expected responses to selection based on genetic parameters. The body weight at birth (BW), weaning weight (WW), 6-month weight (6W), 9-month weight (9W), 12-month weight (YW), pre-weaning average daily gain (ADG1, birth to 3 months), post-weaning ADG2 (3–6 months), ADG3 (6–9 months), ADG4 (9–12 months) and ADG5 (3–12 months) were 2.67, 10.05, 14.56, 18.36, 21.36, 80.13, 49.05, 43.00, 34.21 and 41.18 g, respectively. Univariate analyses were carried out using animal and sire models to estimate variance components. Heritability obtained from animal model for BW was 0.36 and the values for other body weight traits were almost unity. Heritability estimate for pre-weaning ADG1 was 0.31. Very high genetic variability was observed in spite of long-term selection and this sustenance of variability is one of the main advantages of a group breeding scheme, combining several flocks of smaller size. An increasing genetic and phenotypic trend was noticed for almost all the traits studied. The expected responses calculated based on genetic parameters also indicated scope for improvement.  相似文献   

4.
The importance of birth-to-weaning average daily gain as a determinant of weight at a final age and yield of marketable pork was investigated. Treatments were imposed to create variation in birth-to-weaning ADG independent of birth weight. Newborn pigs were cross-fostered to create litters of four through 14 pigs/litter. Creep feed was offered to pigs from 5 d of age or during last 2 d before weaning at 13 to 20 d (average = 17 d). Growth rate and carcass dissection data were obtained from 195 barrows that were slaughtered at an average age of 170 d (SD = 7.5), weight of 109 kg (SD = 10.5). All traits measured were influenced by birth dam and sire (P < 0.01). Quadratic and cubic effects (P < 0.09) of litter size on birth-to-weaning ADG and weaning weight were different between the creep feeding treatments. Data revealed a positive influence (P < 0.04) of creep feeding from 5 d of age on birth-to-weaning ADG and weaning weight in larger size (> 8) litters. Importance of the independent variables birth weight, birth-to-weaning ADG, weaning weight, and birth weight plus birth-to-weaning ADG in determination of measures of postweaning growth and yield of marketable pork were examined by step-down regression analysis. Initial models included the linear and quadratic effects of the independent variables. In general, R2 for models ranked birth weight < birth-to-weaning ADG < d-17 weaning weight < birth weight + birth-to-weaning ADG. The R2 of models for BW at 170 d of age were 0.11 (P < 0.01) using birth weight as the independent variable, 0.16 (P < 0.01) using birth-to-weaning ADG, 0.19 (P < 0.01) using d-17 weaning weight, and 0.21 (P < 0.01) using birth weight + birth-to-weaning ADG. The model for effect of birth-to-weaning ADG on BW at 170 d of age indicated that a 10-g advantage in birth-to-weaning ADG produced a 0.94-kg advantage in BW at 170 d of age. Positive relationships (P < 0.05) between birth-to-weaning ADG and measures of postweaning growth and carcass yield suggest management practices that increase birth-to-weaning ADG may be advantageous in pork production.  相似文献   

5.
Information on 936 birth weights (BW), adjusted weaning weights (AWW) and average daily gains (ADG) from Brahman (B), Indubrazil (I), Gyr (G) and commercial Zebu (C) cattle and their crosses were obtained from the records of a farm in the State of Yucatan, Mexico. Two statistical models were used to analyse the data: the first included the effects of year and season of birth, sex of the calf, cow's parity number and breed group. The other model included the same environmental effects as the previous model and the genetic components of breed group (breed additive, breed maternal and heterosis effects). Additive and maternal effects were expressed as deviations from those for the B breed. The means of BW, AWW and ADG for the B breed were 33.3 ± 0.64 kg, 204.0 ± 4.9 kg and 760.06 ± 19.24 g/day, respectively. Both models gave similar results in terms of the variance explained. Additive effects were significant (p < 0.05) for AWW and ADG but not for BW. The minor additive effect was for the C breed (−10.75 kg and −40.77 g for WW and ADG, respectively). Maternal and heterosis effects were not significant (p > 0.05) for any of the traits. The correlation between the breed group means and the means estimated by the prediction equation was r = 0.88. Finally, there was no significant genetic effect on pre-weaning calf performance among the genotypes evaluated. The genetic model can be used to predict the genotype means with a high degree of accuracy. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

6.
This study evaluated the nutritional interrelationship between the growing and finishing phases of crossbred cattle in determining their performance. One hundred and eight animals were used (8 months old, body weight [BW] 211 ± 20 kg). During the dry season, the animals received one of the following supplements: a mineral plus urea supplement (ad libitum, MSD), a protein supplement (1 g/kg BW per day, PR1), or a protein-energy supplement (5 g/kg BW per day, PE). During the rainy season, the animals received one of the following supplements: a mineral without urea supplement (ad libitum, MSR), a protein supplement (1 g/kg BW per day, PR2), or PE (5 g/kg BW per day). The experimental design was completely randomized using a 3 × 3 factorial scheme (for the rainy season) and a 3 × 3 × 2 factorial scheme (for the finishing phase). The supplementation and finishing systems were considered to be the treatments, and the animals were considered to be the experimental units. Dry season supplementation did not affect the average daily gain (ADG) during the rainy season (P = 0.12) or the finishing phase (P = 0.73). An increase in the level of rainy season supplementation reduced ADG by 12% during the finishing phase (P < 0.06). Providing PE during the dry and rainy seasons led to the animals being slaughtered 17 (P = 0.06) and 30 (P < 0.01) days earlier, respectively. Our results indicate that supplementation during the dry season (under poor-quality pasture conditions) does not affect the performance during the rainy season or the finishing phase. Furthermore, while providing PE during the rainy season can reduce ADG during finishing, the higher BW at the beginning of the finishing phase is sufficient to reduce the time of the finishing period.  相似文献   

7.
Present investigation was carried out to study the influence of genetic and non-genetic factors affecting post-weaning performance traits in Thalli sheep. Data on post-weaning growth of Thalli sheep maintained at Livestock Experiment Station, Rakh Ghulaman, District Bhakkar-Punjab, Pakistan during 1977–2003 were subjected to genetic analysis. The average values for weight at 180 and 270 days of age, yearling weight and post-weaning average daily gain were 22.37?±?4.21, 25.96?±?4.90 and 28.93?±?5.20 kg and 28?±?0.01 g/day, respectively. Weight at 180, 270 and 365 days of age and post-weaning average daily gain were significantly affected by year of birth, sex, type of birth and weaning weight (covariable) whereas season of birth was a significant source of variation for 180 and 270 days of age. The heritability estimates for 180 and 270 days, yearling weight and post-weaning average daily gain were 0.07?±?0.02, 0.08?±?0.02, 0.07?±?0.02 and 0.07?±?0.02, respectively.  相似文献   

8.
A retrospective cohort study was designed to examine the effect of sex, season of birth, type and year of birth, and birth weight on lamb mortality. The method used involved analysis of breeding records for Sahelian sheep kept on a breeding station at Pong-Tamale in northern Ghana from 1994 to 2000. The pre-weaning and post-weaning mortalities were 10% (n = 505) and 19% (n = 453), respectively, while the overall mortality from birth up to 12 months of age was 28% (n = 505). Compared to the pre-weaning period, the post-weaning period recorded significantly higher proportions of deaths in male, single-born, lambs born in the rainy or dry seasons, and in lambs with low (<3 kg) or high (> or =3 kg) birth weight. The odds and risks of death for male lambs were about one and a half times those for females at post-weaning. Lambs born in the dry season had significantly higher mortality than those born in the rainy season. Lambs that died by the time of weaning were not significantly different in weight at birth from those that survived. The mean birth and weaning weights of single-born lambs were significantly higher than those for twins. The mean pre-weaning ADG was significantly higher in lambs born as singles compared to that for twins. The season of birth had influence on mean birth weight, with those born in the rainy season having significantly higher weights than those born in the dry season. The year of birth significantly affected birth weight, weaning weight, weight at 12 months and ADG at all stages of the lambs' life. The study concluded that the most significant risk factors for lamb mortality included sex of the lamb, season of birth and birth weight. The last two could be manipulated, to some extent, to reduce lamb mortality.  相似文献   

9.
Data from purebred and crossbred calves, consisting of Afrikaner (AF), Charolais (CH), Simmental (ST) and Hereford and Aberdeen Angus combined (HA), were analyzed to estimate breed additive effects, breed maternal effects, average individual heterosis and average maternal heterosis. The traits studied were birthweight (BW), weaning weight (WW) and preweaning average daily gain (ADG) (kg). A multiple regression procedure was used for the estimation of these genetic effects and for predictions for breed crosses that were not included in the data set. Crosses containing higher proportions of CH or ST were heavier at birth and weaning than the other crosses and purebreds. The direct effects of BW were negative and significant (P < 0.05), except that of the CH, which was the highest. The regression coefficients were ?24.87, ?18.16, ?22.80 and ?27.02 for AF, CH, ST and HA, respectively. The maternal effects were not significant. Both average individual and average maternal heterosis regression coefficients were also not significant for BW. Regression coefficients of both direct and maternal effects for WW were not significant and were characterized by large standard errors. Average individual heterosis and average maternal heterosis regression coefficients were, however, significant (P < 0.01) and the values were 5.34 and 2.19, respectively. A similar pattern was observed for ADG, except for the regression coefficients of the maternal effects, which were significant, with larger estimates for AF and ST reflecting their superior mothering ability. The values were 0.01, 0.13, 0.13, 0.03; ?0.82, ?0.85, ?0.85, ?0.81; 0.03 and 0.01 for direct effects and maternal effects of AF, CH, ST and HA; and average individual heterosis and average maternal heterosis, respectively. Means and standard errors of purebreds and their F1 crosses not included in the dataset were predicted.  相似文献   

10.
The main objectives of this study were to estimate genetic and phenotypic parameters for growth traits and prolificacy in the Raeini Cashmere goat. Traits included, birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain from birth to weaning (ADG1), average daily gain from weaning to 6WT (ADG2), average daily gain from 6WT to 12WT (ADG3), survival rate (SR), litter size at birth (LSB) and litter size at weaning (LSW) and total litter weight at birth (LWB). Data were collected over a period of 28 years (1982-2009) at the experimental breeding station of Raeini goat, southeast of Iran. Genetic parameters were estimated with univariate models using restricted maximum likelihood (REML) procedures. In addition to an animal model, sire and threshold models, using a logit link function, were used for analyses of SR. Age of dam, birth of type, sex and of kidding had significant influence (p < 0.05 or 0.01) all the traits. Direct heritability estimates were low for prolificacy traits (0.04 ± 0.01 for LSB, 0.09 ± 0.02 for LSW, 0.16 ± 0.02 for LWB and 0.05 ± 0.02 for SR) and average daily gain (0.12 ± 0.03 for ADG1, 0.08 ± 0.02 for ADG2, and 0.07 ± 0.03 for ADG3) to moderate for production traits (0.22 ± 0.02 for BWT, 0.25 ± 0.02 for WWT, 0.29 ± 0.04 for 6WT, 0.30 ± 0.02 for 9WT, 0.32 ± 0.05 for 12WT). The estimates for the maternal additive genetic variance ratios were lower than direct heritability for BWT (0.17 ± 0.03) and WWT (0.07 ± 0.02).  相似文献   

11.
Three commercial trials were conducted to evaluate the use of dexamethasone (Dex) and/ or isoflupredone (Predef) in improving preweaning growth performance of neonatal pigs. The objectives of the commercial trials were threefold: 1) to evaluate Predef in comparison with Dex; 2) to address the sexual dimorphic growth response observed in a previous commercial trial; and 3) to determine whether there is any benefit of providing Dex treatment to pigs being fed supplemental milk. In Exp. 1, 276 pigs (Triumph 4 x PIC Camborough 22) were assigned according to birth weight and sex to three treatments. Treatments included saline (Control), Dex (2 mg/kg BW i.m. injection of Dex), or Predef (2 mg/kg BW i.m. injection of Predef 2X) within 24 h after birth. A treatment effect was observed for BW at weaning (P < 0.001), with pigs injected with Predef being 0.51 kg lighter than Control and Dex-treated pigs. The lower BW of Predef-treated pigs at weaning were a result of a lower ADG (P < 0.001) during the preweaning period compared with Control and Dex pigs. In Exp. 2, 703 pigs (Triumph 4 x PIC Camborough 22) were assigned according to birth weight and sex to three treatments. Treatments included either an i.m. injection of saline (Control), Dexl (1 mg/kg BW of Dex), or Dex2 (2 mg/kg BW of Dex) within 24 h after birth. No treatment effects were observed for BW at weaning (P = 0.24) or ADG (P = 0.19). In Exp. 3, 342 pigs (Genetiporc) were assigned according to birth weight and sex to two treatments. Treatments included either an i.m. injection of saline or Dex (2 mg/kg BW) within 24 h after birth. All pigs were provided supplemental milk from the time of treatment until weaning age. No treatment effects were observed for BW at weaning (P = 0.13) or ADG (P = 0.11). The negative response to Predef was similar to the growth-suppressive effects observed by others using chronic glucocorticoid treatment. In contrast to our previous findings, Dex did not improve preweaning growth performance regardless of dose or supplemental milk.  相似文献   

12.
The objective of this study was to determine the average daily gain (ADG) of pigs on rural and peri-urban smallholder farms in two districts of Western Kenya, in order to establish a baseline to measure the impact of future management interventions. Average daily gain (kilograms per day) for 664 pigs weighed one, two or three times and the proportion of local and crossbreed pigs was determined. Assuming a uniform birth weight of 1 kg, ADG did not differ between pigs weighed once or twice. Overall, ADG was higher in peri-urban pigs (0.15?±?0.058 kg/day) than rural pigs (0.11?±?0.047 kg/day). Pigs at 1 to 2 months had a higher ADG than those at 3 months or 10 to 12 months and ADG was higher in crossbreed than local pigs. Over the two districts, the ADG was low (0.13?±?0.002 kg/day). Most (87.2 %) pigs were of local breed. Low ADG may be due to malnourishment, high maintenance energy expenditure, high parasite prevalence, disease, and/or low genetic potential. This low ADG of pigs raised on smallholder farms in Western Kenya indicates a high potential for improvement. The growth rate of pigs in Western Kenya must be improved using locally available feedstuffs to make efficient use of resources, promote sustainable smallholder pig production, and improve the livelihood of smallholder farmers.  相似文献   

13.
The present study was conducted to evaluate the effects of high and low supplementation levels pre- and post-weaning on performance, endocrine, metabolic, and reproductive responses of Nellore heifers. Fifty Nellore heifers with 132?±?9.9 kg average body weight (BW) and 138?±?19 days of age were supplemented from 4 to 14 months. The heifers were distributed into five supplementation plans: HH—6 g/kg of BW of supplement pre- and post-weaning, HL—6 g/kg of BW of supplement pre-weaning and 3 g/kg post-weaning, LH—3 g/kg of BW pre-weaning and 6 g/kg of BW post-weaning, LL—3 g/kg of BW pre- and post-weaning, and CC—control, no supplementation. Interactions were not significant (P?>?0.10). The level of supplement fed pre-weaning did not affect any of the performance variables evaluated at the end of the experiment (P?>?0.10). There was a significant effect of supplementation and level of supplementation fed post-weaning on average daily gain (ADG) and final BW (P?<?0.05). Overall ADG was also affected only by supplementation and level of supplement fed post-weaning (P?<?0.05) with animals receiving 6 g/kg of BW post-weaning gaining more weight. Follicular diameter was greater in animals that received 6 g/kg of BW post-weaning (P?<?0.05). In summary, performance, endocrine, metabolic, and reproductive variables evaluated in the current study were improved by the level of supplement fed post-weaning. Heifers receiving supplementation of 6 g/kg of BW post-weaning had greater responses, independent of the level received during the pre-weaning phase.  相似文献   

14.
This study estimated genetic and phenotypic parameters and annual trends for growth and fertility traits of Charolais and Hereford cattle in Kenya. Traits considered were birth weight (BW, kg), pre-weaning average daily gain (ADG, kg/day) and weaning weight (WW, kg); calving interval (CI, days) and age at first calving (AFC, days). Direct heritability estimates for growth traits were 0.36 and 0.21; 0.25 and 0.10; 0.23 and 0.13 for BW, ADG and WW in Charolais and Hereford, respectively. Maternal heritability estimates were 0.11 and 0.01; 0.18 and 0.00; 0.17 and 0.17 for BW, ADG and WW in Charolais and Hereford, respectively. Direct-maternal genetic correlations ranged between −0.46 and 1.00; −0.51 and −1.00; −0.47 and −0.39 for BW, ADG and WW in Charolais and Hereford, respectively. Genetic correlations ranged from −0.99 to unity and −1.00 to unity for growth and fertility traits respectively. Prospects for improvement of growth and fertility traits exist.  相似文献   

15.
试验旨在探讨陆川猪和大白猪胰岛素样生长因子2(insulin-like growth factor-2,IGF2)基因多态性与生长性状的关系,以期为猪生产性状标记辅助选择侯选基因的选择提供理论依据。采用PCR-SSCP技术,在陆川猪和大白猪群体中检测到了1个SNP位点,并将这个SNP位点与生长性状进行关联分析。结果表明,IGF2基因对陆川猪和大白猪初生重、平均日增重影响均显著(P<0.05),对断奶重的影响在大白猪上显著(P<0.05),在陆川猪上不显著(P>0.05),可作为用于育种实践的分子遗传标记。  相似文献   

16.
Data were collected over a period of 21 years (1988–2008) to estimate (co)variance components for birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain from birth to weaning (ADG1), weaning to 6WT (ADG2), and from 6WT to 12WT (ADG3) in Sirohi goats maintained at the Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India. Analyses were carried out by restricted maximum likelihood, fitting six animal models with various combinations of direct and maternal effects. The best model was chosen after testing the improvement of the log-likelihood values. Heritability estimates for BWT, WWT, 6WT, 9WT, 12WT, ADG1, ADG2, and ADG3 were 0.39 ± 0.05, 0.09 ± 0.03, 0.06 ± 0.02, 0.09 ± 0.03, 0.11 ± 0.03, 0.10 ± 0.3, 0.04 ± 0.02, and 0.01 ± 0.01, respectively. For BWT and ADG1, only direct effects were significant. Estimate of maternal permanent environmental effect were important for body weights from weaning to 12WT and also for ADG2 and ADG3. However, direct maternal effects were not significant throughout. Estimate of c 2 were 0.06 ± 0.02, 0.03 ± 0.02, 0.06 ± 0.02, 0.05 ± 0.02, 0.02 ± 0.02, and 0.02 ± 0.02 for 3WT, 6WT, 9WT, 12WT, ADG2, and ADG3, respectively. The estimated repeatabilities across years of ewe effects on kid body weights were 0.10, 0.08, 0.05, 0.08, and 0.08 at birth, weaning, 6, 9, and 12 months of age, respectively. Results suggest possibility of modest rate of genetic progress for body weight traits and ADG1 through selection, whereas only slow progress will be possible for post-weaning gain. Genetic and phenotypic correlations between body weight traits were high and positive. High genetic correlation between 6WT and 9WT suggests that selection of animals at 6 months can be carried out instead of present practice of selection at 9 months.  相似文献   

17.
A blind and controlled field study was conducted on a pig farm in Australia to evaluate the activity of 1% ivermectin solution when injected into pregnant sows that were naturally infested with mites. The study was designed to appreciate the tolerance of the product on sows (litter size, litter birth weights, litter weaning weights, pre-weaning mortality) and to show the effects of sarcoptic mange on the growth performances of their offspring. Twenty sows were selected and ranked on Day-10, prior to the start of the study, on the basis of positive mite counts and parity. Sows were randomly allocated into two groups, A and B. On Day-7, they were injected once with product A (1 ml/33 kg; yielding 300 microg ivermectin/kg BW) or product B (placebo), respectively and then moved to the farrowing unit. Mite counts, ear and body lesions were scored and recorded. The average daily weight gain (ADG) was calculated on piglets from birth to Day-45 (ADG(45)) and birth to Day-70 (ADG(70)). Ivermectin was 100% efficient in preventing the transmission of scabies mites and did not have negative effect on the pregnant sows. Growth performances (ADG(45) and ADG(70)) of piglets from treated sows were significantly higher (452 and 541.5 g per day) than that from untreated sows (433.5 and 518.4 g per day) respectively, confirming that sarcoptic mange is detrimental to the production performances of growing pigs.  相似文献   

18.
Genetic parameters were estimated for 6-month weight (W6), 9-month weight (W9), 12-month weight (W12), average daily gain from birth to 6 months old (ADG6), and Kleiber ratio at 6 months (KL6) traits using 6,442 records obtained from a Raini Cashmere goat flock. The parameters were estimated using the restricted maximum likelihood procedure and applying four animal models excluding or including maternal additive genetic and permanent environmental effects. Heritability estimates for W6, W9, W12, ADG6, and KL6, under the most appropriate model were 0.028, 0.26, 0.29, 0.02, and 0.25, respectively. The estimates of genetic and phenotypic correlations among W6, W9, W12, and ADG6 were high and ranged from 0.73 to 0.99. The estimates of genetic and phenotypic correlations among KL6 and others traits were negative and low. Thus, these estimates of genetic parameters may provide a basis for deriving selection indices for postweaning growth traits also low genetic correlation between growth traits with KL6, it is possible to increase efficiency in Raini kids by multitrait selection.  相似文献   

19.
The objective of this study was to estimate the effect of piglet birth weight on future BW, growth, backfat, and longissimus muscle area of pigs in a commercial U.S. production system. Pigs (n = 5727) at a commercial farm were individually weighed and identified within 24 h of birth. Weights were collected prior to weaning (n = 4108), after finisher placement (n = 3439), and 7 (n = 1622) and 16 (n = 1586) weeks into finishing; hot carcass weight was also collected (n = 1693). Average daily gain during lactation, nursery, finishing, and overall (birth to 16 weeks into finishing) was calculated. During BW collection 16 weeks into finishing, real-time ultrasound backfat thickness and longissimus muscle area were measured. Sex × birth weight (linear and quadratic) interactions were observed for BW at weaning and finisher placement and daily gain during pre-weaning and nursery. Linear birth weight × cross foster interactions were observed for weaning weight and pre-weaning gain. Linear and quadratic effects of birth weight on BW at weaning, finisher placement, 7 and 16 weeks into finishing, and hot carcass weight and average daily gain during pre-weaning, nursery, finishing, and total were observed. For all measures of BW and average daily gain, as birth weight increased subsequent BW and average daily gain increased at a decreasing rate; however, for the sex × birth weight (linear and quadratic) interactions, heavier birth weight barrows were lighter and grew slower than gilts of comparable birth weight. Worth noting, the birth weight × sex interactions described very few pigs in the extreme portion of the birth weight distribution. For birth weight × cross foster interactions, non-cross fostered pigs were increasingly heavier and faster growing as birth weight increased compared to cross fostered pigs. Heavier birth weight pigs tended to have increased backfat depth (P = 0.07). Linear and quadratic effects of birth weight on longissimus muscle area were observed; as birth weight increased muscling increased at a decreasing rate. Regardless of interactions or period of production, increased birth weight resulted in heavier future BW, faster daily gain along with larger longissimus muscle area prior to harvest. In all instances the magnitude of the negative effect of birth weight increased as birth weight decreased.  相似文献   

20.
Progeny (n = 861) of tropically adapted breeds [Tuli (TU), Senepol (SE), and Brahman (BR)] and temperate breeds [Angus (AN) and Polled Hereford (HP)] were evaluated for birth and weaning traits in each of 5 yr. Multiparous crossbred cows representing three genetic types [British (Bt), ½BR½Bt, and ¾Bt¼BR] were mated to AN, HP, TU, SE, and BR sires, with the exception that BR sires were not mated to ½BR½Bt cows. Calving season was January through early March. Following calving, cows were provided bermudagrass hay and bahiagrass hay and had limited access to rye and ryegrass pastures. Cow and calf pairs grazed bermudagrass and bahiagrass pastures as available until weaning without access to creep feed. Male calves were castrated at birth and were not implanted. Data included birth weight, cannon bone length at birth, weaning weight, weaning hip height, ADG from birth to weaning (ADGBW), ADG from birth to April (ADGBA), ADG from April to weaning (ADGAW), and weight per day of age (WDA). Data were analyzed by PROC Mixed using a model that included calf genetic type, calf sex, calf birth day of year, and calf genetic type × calf sex interaction. Random effects were cow age, birth year, and sire and dam of calf. Calf genetic type and calf sex were significant sources of variation for all characteristics. Linear contrasts revealed that BR-sired calves were heavier at birth, had longer cannon bones at birth, and were taller at weaning (P<0.01). Tuli- and SE-sired calves were similar to AN- and HP-sired calves for birth weight, cannon bone length at birth, and weaning hip height. Angus-, HP-, and BR-sired calves were heavier at weaning compared with TU-sired calves, and SE-sired calves were intermediate for weaning weight (P<0.01). In conclusion, the TU-sired calves were smaller at birth and at weaning when compared with BR-sired calves. The TU- and SE-sired calves appear to offer more moderate size and growth rate through weaning than do the BR-sired calves.  相似文献   

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