Content uploaded by Mahendra Kumar Padhi
Author content
All content in this area was uploaded by Mahendra Kumar Padhi on Aug 21, 2015
Content may be subject to copyright.
A preview of the PDF is not available
Inheritance of body weight, shank length and production traits in PD1 (Vanaraja male line)
Abstract and Figures
Padhi, M.K., Chatterjee, R.N. 2012. Inheritance of body weight, shank length and production traits in PD1 (Vanaraja male line). Indian Journal of Poultry Science, 47(3): 269-273. Body weight, shank length and different production parameters were recorded at different ages in a selected flock of PD1 (Vanaraja male line). The body weight, egg weight, and shank length increased with age. Egg production upto 72 weeks of age was 142.27 eggs and the age at sexual maturity was 173.26 days. Egg production per bird at 4 weeks of interval from 21 to 72 weeks of age varied from 1.94 to 14.35 eggs and the peak egg production was recorded during 29 to 32 weeks of age. The heritability estimates for body weight at 6 weeks and weight at sexual maturity were low in magnitude, however, the estimate was moderate to high for the body weight at 32, 40, 64 and 72 weeks of age. Sire component estimates were higher than the dam component estimates for body weights. Shank length at 6 weeks of age showed low estimates at early ages and as the age of measurement increases the heritability estimates increased. Dam component estimates were higher than the sire component estimates. Heritability of age at sexual maturity was moderate in magnitude. Estimates of heritability for egg production were low to moderate in magnitude with dam component estimates being higher. Egg weight showed moderate to high heritability estimates and sire component was higher indicating the presence of additive genetic effect. Genetic and phenotypic correlations for different important traits were calculated. Shank length with egg production to 40 weeks of age and egg weights were positively correlated, whereas, body weight with egg production to 40 weeks of age was negatively correlated. Egg weight and age at sexual maturity showed negative correlation with egg production. The results indicated that for improving the desired traits appropriate breeding and selection methods need to be followed based on heritability estimates and correlation.
Figures - uploaded by Mahendra Kumar Padhi
Author content
All figure content in this area was uploaded by Mahendra Kumar Padhi
Content may be subject to copyright.
... The genetic correlations from sire + dam component between ASM and BW40 in the present study (Table 4) were positive and high which were in close agreement with the reports of Rajkumar et al. (2011b) and Sreenivas et al. (2012), whereas it has negative association with egg production, in line with the reports of Rajkumar et al. (2011b). The phenotypic correlations between ASM and body weights in the present study were negative and low in magnitude, whereas with egg weights were positive and high in magnitude, which were in agreement with the reports of Padhi and Chatterjee (2012). The correlation between ASM with EP40 was negative, which was similar to the findings of Rajkumar et al. (2011b). ...
... The genetic correlations from sire + dam component between body weights with egg weights in the present study were positive. Correlations between BW20 with EP40 were found to be positive, while that of BW40 with EP40 were found to be negative similar to the reports of Padhi and Chatterjee (2012), Rajkumar et al. (2021b;. The phenotypic correlations of body weights with egg weights in the present study were positive and low in magnitude whereas those of egg production with BW20 and BW40 were negative, which were in line with the reports of Padhi and Chatterjee (2012). ...
... Correlations between BW20 with EP40 were found to be positive, while that of BW40 with EP40 were found to be negative similar to the reports of Padhi and Chatterjee (2012), Rajkumar et al. (2021b;. The phenotypic correlations of body weights with egg weights in the present study were positive and low in magnitude whereas those of egg production with BW20 and BW40 were negative, which were in line with the reports of Padhi and Chatterjee (2012). The genetic correlations among egg weights at different ages in the present study were positive and low to high magnitude. ...
A comprehensive study was carried out in Gramapriya male line (PD-6) chicken with respect to growth, production and egg quality traits utilizing the data generated from 1995 chicks and 230 hens in S-8 generation at ICAR-Directorate of Poultry Research, Hyderabad, Telangana. Highly significant differences among hatches were observed for body weight, shank length, age at sexual maturity (ASM), egg production (EP), egg weight (EW) and egg mass (EM). The least squares mean of body weights (BW) at 2, 4, 6, 20 and 40 weeks of age were 187.03±0.97, 499.74±1.58, 838.67±5.69, 2074.93±9.82 and 2891.26±15.25 g, respectively. The least squares mean of shank lengths at 4 and 6 weeks of age were 70.19±0.09 and 87.48±0.12 mm respectively. The h2 for body weight and shank length at six weeks of age was 0.31±0.06 and 0.23±0.05, respectively, which were moderate to high in magnitude. The ASM was 168.94±0.71 days. The EP40 was 69.87±1.24 eggs with an egg weight of 55.11±0.22 g. The EM40 was 3840.02±67.52 g. The heritability estimate was low for EP40 (0.09±0.11). The gradual improvement in primary trait (SL6) in parent line will improve the performance in terminal cross ‘Gramapriya’ which ultimately benefits the farmers.
... days, 67.65±0.20 numbers, respectively (Mishra et al. 2006). Padhi et al. (2012) studied the reproduction traits in Vanaraja male line and reported the means of ENO40 as 52.80±0.05. ...
... for egg number to 280 days of age. Padhi and Chatterjee (2012) reported the maximum likelihood heritability estimates for body weight at 6 weeks to be low in magnitude, body weight at 40 weeks had high estimate (0.62), and low estimates were observed for AFE (0.01) and ENO40 (0.10). In Vanaraja male line the LSML heritability were estimated to be low (0.01 to 0.10) for traits viz. ...
... Positive genetic correlation, ranging from (0.31 to 0.34), between AFE and BWT traits were observed and the phenotypic correlation estimates between these traits were low and negative (-0.03 to 0.09) (Sang et al. 2006). Mishra et al. (2006) observed positive and high genetic and phenotypic correlationsamong body weight at differentages; egg number at 40 weeks had negative correlation with body weight at all age.Genetic correlations of BWT20 with AFE and ENO40 were negative -0.14 and -0.18, respectively and the estimates of phenotypic correlation were 0.24 and 0.05, respectively (Padhi and Chatterjee, 2012). In a study on Vanaraja male line the genetic and phenotypic correlation estimates between BWT2, BWT4 and BWT6 were positive and high (Padhi et al. 2015). ...
The present investigation included the data of 29,879 birds pertaining to 8 generations, from 2010 to 2018 on growth line (PB1) of IBL-80 broiler. The mean estimates of growth and fertility traits were BWT0 (39.97±0.05 gms), BWT5 (1189.17±1.45 gms), BWT10 (1723.59±6.26 gms), BWT15 (2165.71±7.90 gms), BWT20 (2611.23±4.10 gms), ADG5 (32.36±0.07 gms/day), ADG10 (13.09±0.14 gms/day), ADG15 (12.38±0.13 gms/day), ADG20 (12.65±0.13 gms/day), AFE (171.80±0.21 days) and ENO40 (62.47±0.25) which indicated higher growth performance of PB1 affected its fertility performance. ADG5 had highest estimate indicating higher growth during chick stage. Least squares analysis indicated that effect of gender, month of hatch and generation were significant (p less than 0.01) for all growth and fertility traits. AIREML heritability estimates indicated appreciable additive variance in BWT0 (0.50), BWT5 (0.54) and ADG5 (0.20). Other growth and fertility traits had lower heritability which was due to stage wise selection in breeder flock. Phenotypic and genetic correlation estimate indicated negative association between growth and fertility traits.
... Shank length: There was an increase of 2.07 mm shank length from 16 to 20 weeks of age (Table 1). The shank length recorded in the present study at 20 weeks of age was higher than the report in PD1 (Padhi and Chatterjee 2012). Higher shank length at 20 weeks of age in this line may improve the shank in the commercial crosses which will be useful for the faster running of bird in the field to escape from the predators. ...
... Production traits: Age at sexual maturity observed to be 180.30 days (Table 1) which was higher than the report of Padhi and Chatterjee (2012), may be due to environmental effect. The age at sexual maturity in this breed was higher than the available literature in other meat type birds (Rajkumar et al. , 2012. ...
... Body weight at 20, 40 and at sexual maturity showed heritability low to moderate in magnitude and as the age advances the estimates from sire + dam component variance increased (Table 2). Though moderate to high heritability estimates was reported for body weight in the PD1 line by Padhi and Chatterjee (2012) but the findings was in agreement with, as the age advances, the heritability estimates increases. Lower magnitudes may be due to less variation in the population. ...
Vanaraja male line (PD1) was evaluated for different production traits up to 60 weeks of age and egg quality traits were recorded at different ages. Body weight at 20 and 40 weeks of age were 2037 and 2903 g, respectively. Least square estimate for age at sexual maturity was 180.30 days. Egg production up to 40 and 60 weeks of age were 42.34 and 92.06 eggs, respectively. There was increase of 2.07 mm shank length between 16 to 20 weeks of age. Heritability estimates for age at sexual maturity, body weight at 20 and 40 weeks of age, egg production upto 40 weeks and egg weight at 32 weeks of age were low in magnitude. However, heritability estimates for Shank length at 20 and first egg weight showed moderate to high heritability. Genetic correlation between shank length and egg production up to 40 weeks of age was positive, however, body weight at 40 weeks of age with egg production showed negative correlation and moderate in magnitude. Egg quality parameters showed significant difference between different age of measurements and as the age increases the egg quality parameters decreases. Results indicated that most of the production traits in PD1 line have less additive genetic variation which should be considered in the selection programme. © 2015, Indian Council of Agricultural Research. All rights reserved.
... Brooding period: Body weight obtained in the present study at 4 and 6 weeks of age and shank length recorded at 6 weeks of age were higher (Table 1) than the report of Padhi et al. (2012a) and Padhi and Chatterjee (2012). It is to be mentioned that PD1 is being selected for higher shank length at 6 weeks of age keeping in view that this can show its effect in Vanaraja commercial through inheritance and heterosis so that higher shank length Vanaraja can run faster in the backyard to escape from predators. ...
... The heritability estimates for all juvenile body weights and conformation traits are low in magnitude and estimates of dam component variance were higher indicating the importance of dominance or maternal effect for these traits during the early ages (Table 1). Low to moderate heritability for body weights and shank length were report by Padhi et al. (2012a) and Padhi and Chatterjee (2012). The low heritability for these traits was due to lower additive genetic variation for these traits in the line. ...
... High genetic correlation between body weight with shank length and keel length were also observed indicating that the selection for higher shank length will also improve the other traits as a correlated response. Similar observations were also reported by Padhi et al. (2012a) and Padhi and Chatterjee (2012). Correlations between shank length and keel length were positive and high. ...
The present study was undertaken to investigate growth, conformation, production and reproduction performance of PD1 (Vanaraja male line). The data collected for different periods from the birds were produced using 50 sires and 250 dams through pedigreed mating. Body weight was 640.21 g and shank length 75.39 mm at 6 weeks of age in pooled sex. In female the shank length increases faster up to 12 weeks of age and at 20 weeks it reached the maximum length, whereas other traits like body weight, keel length and breast angle increased up to 20 weeks of age. The ASM was 188 days and egg production up to 40 weeks of age was 46.29 eggs with egg weight at 40 weeks 54.61 g. The fertility % and hatchability % on total egg set and fertile egg set were 90.46, 83.20, and 91.38%, respectively. The heritability estimates for juvenile body weight and conformation traits are low in magnitude. Growing period body weight showed moderate heritability estimates, whereas, conformation traits during growing period showed low to moderate heritability estimates. Egg production and age at sexual maturity showed low heritability estimates. Fertility and hatchability % showed moderate heritability estimates. Genetic and phenotypic correlation were estimated between different traits at different period and showed varying levels of correlations estimates. The results indicated that PD1 line has the potential for further improvement and to be used as male line to produce backyard variety and to increase the performance of Vanaraja commercial.
... One such line PD1 is being developed for higher shank length to be used as male parent for backyard poultry. The performances of PD1 in respect to different traits were reported in literature (Padhi et al. 2012a(Padhi et al. , 2012bPadhi & Chatterjee 2012;Padhi et al. 2013a). The use of PD1 for different two-way crosses was reported (Padhi et al. 2013b;Padhi et al. 2014a). ...
... The egg production from 65 to 72 weeks of age reduced and in last 4 weeks of age the egg production was 14.78 eggs, which was little more than 50% production. Decrease in egg production towards later part of cycle was reported in PD1 by Padhi and Chatterjee (2012). However, it is to be mentioned that the present cross was evaluated first time in the institute. ...
Objective of the work was to develop a three-way cross for egg-type backyard chicken using male and female lines developed from exotic chickens. To improve the egg production further and to get colour plumage pattern, the two-way cross PD1 X IWI males were crossed with PD3 females to produce three-way cross (PD1 X IWI X PD3). The crossbred was evaluated for different traits upto 72 weeks of age. Sexual dimorphisms were evident from two weeks onwards for body weights and shank length differ significantly (P < .05) between male and female at 8, 12 and 16 weeks of age. Male were reared upto 16 weeks of age, and at 16 weeks, body weight of male and female were 1670 and 1096 g, respectively. Carcass quality measured at 16 week of age recorded 66.12% eviscerated carcass yield, 4.84% giblet and 0.30% abdominal fat. Egg production performance recorded from 17 to 72 weeks of age at 4 weeks interval showed significant (P < .05) difference between different periods, and peak egg production was recorded during 29–32 weeks. At 69–72 weeks period, the egg production per bird was 14.78 eggs. Egg production upto 40, 52, 64 and 72 weeks of age were 91.71, 105.84, 204.88 and 233.28 eggs, respectively. Age and weight at sexual maturity were 163.14 days and 1702 g, respectively. Egg weight recorded at 4 weeks interval starting from 20 weeks of age showed linear increase upto 56 weeks of age with significant differences at different ages. The results indicate that the cross may be of use for egg-type poultry in the backyard. However, before large-scale propagation, the cross has to be evaluated in the field.
... Egg production at 40 weeks (100.41 ± 1.91) was higher compared to Miri (33.59 ± 0.99 days) [7], Vanaraja (52.8 ± 0.05) [22], Naked neck chicken (64.18 ± 0.13) [13], CARI-Nirbheek (59.94 ± 0.41) [23]. Higher EP 52 was reported in Black Nicobar Chicken (192.14) ...
... al. (2012a). In PD1 the shank length was higher than the reports of Padhi et al. (2012aPadhi et al. ( , 2012b and Padhi and Chatterjee (2012) in the same stock but at early generations. This finding indicates the improvement of shank length over the generations. ...
Present study was undertaken to compare the male line of Vanaraja, Vanaraja and control broiler in respect to their juvenile traits and to study the genetic parameters in Vanaraja male line (PD1). Body weight, feed conversion, conformation traits and carcass quality were measured. Body weights showed significant difference between different genetic groups and lowest body weight recorded in Vanaraja followed by PD1 and control broiler. The gain in body weights at 2 weeks interval showed significant difference between genetic groups and also differ significantly at different periods within a genetic group. All the conformation traits studied showed significant differences between genetic groups and for increase in shank and keel length during different periods. FCR was significantly better in PD1 and control broiler than Vanaraja. Carcass quality traits measured at 12 weeks of age showed significant difference for abdominal fat% and back+neck% between PD1 and Vanaraja. Vanaraja recorded significantly lower abdominal fat% compared to PD1. Heritability estimates for juvenile body weights in PD1 were moderate in magnitude. All conformation traits showed low to moderate estimates of heritability in magnitude for the traits measured at different ages. Correlations for body weights with different conformation traits were high in magnitude. Correlations between the same traits measured at different weeks showed positive and high correlation. The results revealed that the selection in PD1 may improve the performance of the line and also improve the performance in Vanaraja which is being used as dual purpose backyard poultry through utilization of heterosis for different traits.
... Significant shank length between different genetic groups at different ages irrespective of sexes was available in literature (Padhi et al. 2012a, Kundu et al. 2015. Padhi and Chatterjee (2012) reported only 0.09 mm increase in shank length from 20 to 40 weeks of age in PD1 pure lines. ...
In the present study, 4 new crosses, viz. PD1× PD4 (A), PD1 × PB2 (B), PD1x PD3 (C) and PD1 × IWI (D) were developed and evaluated under intensive system of rearing. Body weights, conformation traits were evaluated during starter and growing period and production performance were measured up to 72 weeks of age. Body weights at day 0, 2, 4, 6, 7 and 8 weeks of age in the starter period and at 10, 12, 14, 16, 18 and 20 weeks of age during growing period differed significantly between crosses in both male and female. Irrespective of age, cross B recorded higher body weight compared to other crosses. Shank length and keel length measured at 6, 8, 18 and 20 weeks of age in both the sexes differed significantly between the crosses. The maximum shank and keel lengths were achieved by 20 weeks of age. Feed conversion ratio (FCR) from 0-8 weeks of age was the best in B followed by A, C and D. The age at sexual maturity (ASM), weight at sexual maturity, body weight and shank length at 40 weeks of age, egg production up to 72 weeks of age differed significantly between different crosses. Egg weights measured at different weeks of age also differed significantly between the crosses. The egg production up to 72 weeks of age was the highest in C followed by D, A and B. Mortality % was lowest in D at different period. The results indicated that B may be useful for coloured meat type birds in rural areas whereas C and D cross may be useful for egg type as well as dual purpose backyard poultry. Cross A may be useful for dual type backyard poultry.
Blood samples from 180 birds pertaining to a single generation of PB1 parent line were collected for present study. The birds were raised under standard management and different growth variables were recorded up to 20 weeks of age. Age at first egg and egg production till 40 weeks of age was recorded in females. PCR-RFLP analysis was used to screen individuals with polymorphisms in IGF1 promoter region and three genotypes AA, AC and CC were identified at frequencies of 0.79, 0.18 and 0.03, respectively. CC homozygotes were lower with respect to their performance in growth and fertility traits. Sequencing results of both alleles revealed T244G transversion mutation in the C allele. Gene regulation analysis confirmed that such transversion resulted in non-binding of Oct-1 transcription factor at 241 to 250 bp in C allele, causing down regulation of the gene. The mutations in the promoter sequence affected the transcriptional gene regulation affecting growth and fertility performance.
Qingyuan partridge chicken is an important indigenous chicken in China. In its breeding schemes, chickens are usually selected at the age of 105‐day‐old for five traits, including body weight (BW), shank length (SL), shank girth (SG), comb height (CH) and feather maturity (FM). At present, genetic parameters of the aforementioned traits have still not been studied in Qingyuan partridge chickens. The objectives of this study were the following: (1) to investigate whether the optimal statistical models of these traits need to consider maternal genetic and permanent environmental effects in late‐feathering Qingyuan partridge hens, and (2) to estimate genetic parameters for these traits based on the optimal models. The numbers of records for BW, SL, SG, CH and FM were 13,721, 13,671, 13,670, 13,669 and 13,672, respectively. Variance components were estimated using average information‐restricted maximum likelihood method, and the optimal model was determined based on Bayesian information criterion. More specifically, the optimal model for BW considered maternal genetic and permanent environmental effects in addition to direct additive genetic effect; SL, SG and FM considered direct and maternal genetic effects; and CH considered direct and maternal genetic effects, and the covariance between them. The direct heritabilities of these traits estimated using the optimal models were 0.21 ± 0.04, 0.30 ± 0.05, 0.40 ± 0.05, 0.59 ± 0.09 and 0.09 ± 0.04, respectively; the maternal heritabilities were 0.01 ± 0.04, 0.05 ± 0.05, 0.04 ± 0.05, 0.09 ± 0.09 and 0.03 ± 0.04, respectively. Maternal genetic effect evidently played an important part in FM and maternal heritability accounted for 30 per cent of total heritability. Furthermore, the direct and maternal genetic effects for CH were estimated to be negatively and moderately correlated (−0.51 ± 0.11). For all traits, neglecting existent maternal effects biased the estimation of direct heritability. Therefore, to implement optimum breeding strategies for improvement of these traits in Qingyuan partridge hens, maternal effects should be taken into consideration.
A comprehensive study was undertaken to investigate the reproductive, growth and production performance in a complete production cycle of 72 weeks of age in naked neck broiler breeders. The data collected on chicks (927) for juvenile growth and 196 hens for production parameters produced from 40 sires and 160 dams in a pedigreed mating was analyzed for evaluating the performance in naked neck chicken. The mean fertility and hatchability (FES: fertile egg set and TES: total egg set) % was 81.09, 82.14 (FES) and 75.46 (TES), respectively in naked neck hens. The mean body weight at 4 and 6 weeks of age was 510.35and 1058.86g, respectively with a shank length of 79.62mm (6 weeks) with moderate to high heritability estimates. The ASM in naked neck birds was 160.11 days with moderate heritability (0.24). The body weight of hens at 20, 40, 52, 64 and 72 weeks of age was 2455.60, 3046. 89, 3297.44, 3542.89 and 3805.13g, respectively. The egg weight varied from 53.20 at 28 weeks of age to 70.45g at 72 weeks of age with low to moderate heritability. The part period egg production to 40 weeks was 64.18 with an annual production of 164.37eggs which was fairly reasonable for a broiler breeder chicken. The correlation coefficients revealed strong positive and significant association between body weights at different ages, body weights and egg weights, while negative association between body weights and egg production. The overall performance of naked neck broiler breeders suggests that it offers a bright future for tropical broiler production under the predictions of global warming and temperature rise.
The present study was conducted to evaluate the production performance of indigenous Miri type chickens and improved varieties like Gramapriya and Vanaraja maintained at the ICAR Institute farm in Meghalaya, India. All three genetic groups were evaluated for weekly body weight from 0 day to 8 weeks of age, biweekly body weight from 8 to 14 weeks of age and at 20 and 40 weeks of age, feed intake and feed conversion ratio (FCR) up to 8 weeks of age, age at sexual maturity, egg production rate, shank and keel length and egg quality traits at 40 weeks of age. There were significant differences among all 3 genetic groups for body weights, keel and shank length, sexual maturity, egg production rate, egg weight and egg quality traits such as shell thickness, specific gravity and albumen index. Miri type had significantly early sexual maturity, better shell thickness, higher specific gravity and egg production rate (40 weeks), lesser feed intake and better FCR than the improved varieties. On the other hand improved varieties had significantly higher body weight at different ages, shank and keel length, egg weight (at sexual maturity and 40 weeks of age) and better egg production rate during 40 to 52 weeks of age. Among improved varieties, Vanaraja had significantly higher body weight, shank and keel length, higher feed intake and better FCR than the Gramapriya variety, while Gramapriya had better egg production rate, early sexual maturity and higher egg mass. There were no significant differences between Vanaraja and Gramapriya for body weight at day-old and egg weight (at sexual maturity and 40 weeks of age). In conclusion, indigenous chickens could perform better than improved varieties for certain economic traits under the same management and rearing conditions.
THE relatively recent introduction of statistical methods in the analysis of problems concerned with the inheritance of quantitative
traits has made the literature on the subject somewhat foreboding to those unfamiliar with the techniques involved. If practical
applications of these investigations are to be made, some effort must be spent in bridging the gap between the theoretical
investigators and the people who are in a position to make use of their results.
It is the intent of this paper to present in detail a method of estimating heritability which is applicable to many of the
heritability problems confronting poultry geneticists. Lerner (1950) has indicated in general the procedure to be used in
the analysis of variance components, but a considerable knowledge of statistics is required to carry through the analysis
correctly. The analysis would be quite simple, if the subclass numbers were equal, but this usually is not the case, . . .
The chicks used in this experiment were obtained from a population of naked neck broiler chickens that has been kept in NAPRI since 1998. Six Hundred chicks were obtained from four hatches, one week apart. At hatch, pedigreed chicks were wing-banded and housed on deep litter in an open house. Body weights were measured biweekly up to 8 weeks of age. Other measurements taken include Neck length, Back length, keel length and breast angle. The general least square means were 37.22 ± 0.32, 210.46 ± 1.97, 744.33 ± 4.31, 1351.3 ± 7.91 and 2428.1 ± 14.61g for wt at day old (WT0D), weight at 2 weeks (WT14D), weight at 4 weeks (WT28D), weight at 6 weeks (WT42D) and weight at 8 weeks (WT56D), respectively. While measurements taken included Neck length, Back length, keel length and breast which were 7.31 ± 0.06, 15.99 ± 0.05, 5.63 ± 0.04, 10.44 ± 0.04cm respectively. The heritability estimates ranged from low value of 3.013 ± 0.08 for keel length to 0.315 ± 0.22 for WT0D. There were negative genetic correlations between WT0D and other traits. This study showed that additive heritabilities are low for linear body measurement and moderate for body weight for naked neck chickens during rearing.
Data on body weight and shank length measurement of 361 birds from 5 hatches, one week apart were analysed to obtain heritability estimates for body weight and shank length at 20, 30 and 40 weeks of age, as well as to establish the genetic and phenotypic correlations between the traits. The mean values for body weight at various ages showed good performance of all birds. The heritability estimates observed for body weight and shank length decreases with increasing age of birds. This observation agreed with the reports of some workers and disagreed with the findings of others. Differences however, in heritability estimates could be attributed to differences in method of estimation, breed, environmental effects and sampling error due to small data or sample size. There were positively high genetic and phenotypic correlations between body weight and shank length at these ages. The coefficient of genetic correlation (rg) ranged between 0.582 and 0.645, while the coefficient of phenotypic correlation (rp) ranged between 0.613 and 0.816. High and positive genetic and phenotypic correlations between body weight and shank length suggest that it was possible to predict body weight of live Rhode Island chickens on the basis of their shank length measurement, as an aid to farmers in areas where sensitive weighing scales are not readily available.
The growth and production properformance of Vanaraja male line was studied on 1274 chicks produced from 50 sires and 150 dams. The data revealed significant sex differences for juvenile body weights. The heritability estimates of body weights and shank length were moderate to high, whereas SRBC titres it was low to moderate. The existence of higher sire component variation for shank length provide scope for further improvement in shank length, the primary trait of selection in the line.
The production performance of 3 Naked neck (NaNa, Nana and nana) genotypes and the inheritance pattern of various economic traits was evaluated in the present study. The pedigreed data collected for various economic traits from 231 hens were analyzed for determination of growth, production and genetic parameters. The performance of Naked neck (NaNa/Nana) genotypes was superior in terms of egg production and egg weights than their normal (nana) siblings. The introgression of Na gene can fore-see a viable alternative for poultry production in tropical countries.