Variance components for birth and carcass traits of crossbred cattle

2006 ◽  
Vol 46 (2) ◽  
pp. 225 ◽  
Author(s):  
W. S. Pitchford ◽  
H. M. Mirzaei ◽  
M. P. B. Deland ◽  
R. A. Afolayan ◽  
D. L. Rutley ◽  
...  
Keyword(s):  
Birth Weight ◽  
Fixed Effects ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Intramuscular Fat ◽  
Carcass Weight ◽  
Production Traits ◽  
Management Group ◽  
Calf Survival ◽  
Sire Breed

During a 4-year period (1994–97) of the Australian ‘Southern Crossbreeding Project’, mature Hereford cows (n = 637) were mated to 97 sires from 7 breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin and Belgian Blue), resulting in 1334 calves. Heifers were slaughtered at around 16 months and steers at 23 months. The objective of the study was to quantify between- and within-breed genetic variation for numerous production and quality traits in a southern-Australian production system. Calf survival, birth weight and carcass production traits (carcass weight, fat depth, loin eye area, intramuscular fat) were obtained from these cattle. The carcass traits were loge-transformed because of a scale effect on the variance. Data were analysed using multi-variate animal models containing fixed effects of sex with random effects of management group, sire breed and animal. In addition, birth month and age of dam were included as fixed effects for birth weight. Covariances between survival and other traits could not be estimated from the multi-variate model so they were estimated from a series of bi-variate models. On average, management group and sire breed accounted for similar proportions of variance. Heritability ranged from 0.14 (survival), 0.17 (intramuscular fat), 0.28 (loin eye area), 0.29 (P8 fat depth), 0.31 (birth weight) to 0.50 (carcass weight). In general, environmental (management and residual) correlations between meat (carcass weight and loin eye area) and fat traits (fat depth and intramuscular fat) were positive, but the genetic correlations (both between and within breed) were negative. Management and genetic (co)variation has been quantified and can facilitate production of calves with carcasses suitable for specific market requirements.

Evaluation of eleven cattle breeds for crossbred beef production: carcass data from males slaughtered at two ages

1990 ◽  
Vol 50 (1) ◽  
pp. 79-92 ◽  
Author(s):  
C. A. Morris ◽  
R. L. Baker ◽  
A. H. Carter ◽  
S. M. Hickey
Keyword(s):  
Carcass Traits ◽  
Genetic Correlations ◽  
Live Weight ◽  
High Energy ◽  
Carcass Weight ◽  
Standard Errors ◽  
Slaughter Weight ◽  
Random Samples ◽  
Slaughter Age ◽  
Sire Breed

ABSTRACTAn experiment was carried out to compare sire breeds for carcass traits and to estimate heritabilities and phenotypic and genetic correlations. There were 1908 male cattle from 5 birth years. The sire breeds, each evaluated over three locations, were Blonde d'Aquitaine, Charolais, Chianina, Limousin, Maine Anjou, Simmental (four strains: Austrian, French (Pie Rouge), Swiss and West German) and South Devon (i.e. seven imported breeds) and Angus, Friesian, Hereford and Jersey (four local breeds), with a total of 161 sires represented. Each location contained Angus cows and additionally one location contained Hereford cows. Proportionally 0·72 of the cattle were slaughtered at about 20 months of age, whilst random samples from each of the first 4 years were retained for slaughter at about 31 months of age.Sire breeds ranked similarly for live weight at 13 months of age and for pre-slaughter weights at both 20 and 31 months of age. Relative to the Hereford-cross, the seven imported breeds were proportionally 0·054 to 0·072 heavier at slaughter (depending on slaughter age) and they had 0-065 to 0·077 heavier carcasses. Dressing proportions for the Blonde d'Aquitaine, Chianina and Limousin sire breeds were higher by at least 0007 units than for the Hereford-cross. The seven imported breeds were all leaner and had larger areas of m. longissimus than the Hereford-cross cattle. Friesian-crosses also had high live or carcass weights although they were intermediate for fat depth.The interaction of sire and dam breeds were only significant for fat depth (both slaughter ages) and for pre-slaughter and hot carcass weights (31-month slaughter age only). Interactions between sire breed and location were not important.Heritability estimates on data adjusted to a slaughter age of 595 days were: pre-slaughter weight 0·29, hot carcass weight 0·28, dressing proportion 0·14, fat depth 0·03 and m. longissimus area 0·30. Corresponding values on cattle whose records were adjusted to an age of 935 days were 0·56, 0·44, 0·39, 0·37 and 0·29. These values were from cattle grazed on pasture, and were generally lower than those from America (from cattle offered high energy rations). Phenotypic correlations among all pairs of traits were positive, whilst genetic correlations were positive for all pairs except those involving fat depth (where standard errors were large).

Phenotypic and genetic associations between feeding behavior and carcass merit in crossbred growing cattle

2021 ◽  
Vol 99 (12) ◽  
Author(s):  
David N Kelly ◽  
Roy D Sleator ◽  
Craig P Murphy ◽  
Stephen B Conroy ◽  
Donagh P Berry
Keyword(s):  
Feeding Behavior ◽  
Energy Intake ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Intramuscular Fat ◽  
Carcass Weight ◽  
Genetic Associations ◽  
Fat Percentage ◽  
Growing Cattle ◽  
Carcass Merit

Abstract In growing cattle, the phenotypic and genetic relationships between feeding behavior and both live animal ultrasound measures and subsequent carcass merit are generally poorly characterized. The objective of the current study was to quantify the phenotypic and genetic associations between a plethora of feeding behavior traits with both pre-slaughter ultrasound traits and post-slaughter carcass credentials in crossbred Bos taurus cattle. Carcass data were available on 3,146 young bulls, steers, and heifers, of which 2,795 and 2,445 also had records for pre-slaughter ultrasound muscle depth and intramuscular fat percentage, respectively; a total of 1,548 steers and heifers had information on all of the feeding behavior, ultrasound, and carcass traits. Young bulls were fed concentrates, while steers and heifers were fed a total mixed ration. Feeding behavior traits were defined based on individual feed events or meal events (i.e., individual feed events grouped into meals). Animal linear mixed models were used to estimate (co)variance components. Phenotypic correlations between feeding behavior and both ultrasound and carcass traits were generally weak and not different from zero, although there were phenotypic correlations of 0.40, 0.26, and 0.37 between carcass weight and feeding rate, energy intake per feed event, and energy intake per meal, respectively. Genetically, cattle that had heavier carcass weights, better carcass conformation, or a higher dressing percentage fed for a shorter time per day (genetic correlations [±SE] of −0.46 ± 0.12, −0.39 ± 0.11, and −0.50 ± 0.10, respectively). Genetic correlations of 0.43 ± 0.12 and 0.68 ± 0.13 were estimated between dressing difference (i.e., differential between live weight pre-slaughter and carcass weight) and energy intake per feed event and energy intake per meal, respectively. Neither intramuscular fat percentage measured on live animals nor carcass fat score (i.e., a measure of subcutaneous fat cover of the carcass) was genetically associated with any of the feeding behavior traits. The genetic associations between some feeding behavior traits and both ultrasound and carcass traits herein suggested that indirect responses in the feeding behavior of growing cattle from selection for improved carcass merit would be expected. Such changes in feeding behavior patterns in cattle may be reduced by measuring and including feeding behavior in a multiple-trait selection index alongside carcass traits.

scholarly journals Effect of postweaning growth and bulls selected for extremes in retail beef yield and intramuscular fat on progeny liveweight and carcass traits

2009 ◽  
Vol 49 (6) ◽  
pp. 493 ◽  
Author(s):  
J. F. Graham ◽  
J. Byron ◽  
A. J. Clark ◽  
G. Kearney ◽  
B. Orchard
Keyword(s):  
Carcass Traits ◽  
Intramuscular Fat ◽  
Quality Score ◽  
The Other ◽  
Carcass Weight ◽  
Eating Quality ◽  
Growth Path ◽  
Breeding Values ◽  
Estimated Breeding Values ◽  
Sire Breed

The present study is a component of a multi-site experiment, using Bos taurus cattle generated at four locations across southern Australia, designed to examine postweaning growth pathways for progeny whose sires were extreme in retail beef yield and intramuscular fat. Treatment and interaction effects on beef production and meat quality were examined within and across sites. The present paper describes the effect of postweaning growth and sire carcass type on liveweight and carcass traits at the Hamilton site. Angus sires selected on estimated breeding values for extremes in retail beef yield (RBY%), intramuscular fat (IMF%) (estimated breeding values for IMF% are derived by using live-animal ultrasound scanning) or both and sire breed types considered to be more extreme in those traits (Limousin, and Belgian Blue for yield, and Wagyu for intramuscular fat) were joined to crossbred and straight-bred cows. After weaning, the resultant 645 steer and heifer progeny were grown on a fast and slow growth path to ~550 kg and slaughtered, averaging 0.68 kg/day and 22.2 months, and 0.49 kg/day and 27.8 months for growth rate and age at slaughter, respectively. Growth path, sire carcass type and sex affected carcass traits; however, there were no sire carcass type by growth treatment interactions. The fast growth-path cattle were fatter, had more intramuscular fat (measured chemically), a higher Meat Standards of Australia (MSA) USA and AUS marble score, and a higher predicted MSA eating-quality score. Progeny of Wagyu sires were lighter at weaning and slaughter and had a lower hot standard carcass weight than the other sire carcass types. The Belgian Blue and Limousin progeny had a higher dressing percentage, a higher RBY% and a lower P8 and rib-fat depth and lower IMF% than the other sire breed types. Progeny of the high RBY% Angus had a lower rib-fat depth, a lower IMF% and higher RBY% than those selected for high IMF%. There was no difference in IMF% between the Wagyu or the high IMF% Angus. Progeny from the Belgian Blue, Limousin and Wagyu had a larger eye muscle area than the other sire breeds. The results indicate that simultaneous selection for supposedly antagonistic traits of IMF% and RBY% would result in carcass having high values of both measurements. Females were lighter than steers at slaughter, had a lower hot standard carcass weight, were fatter at the P8 and rib, and had a higher marble score and IMF%, a lower yield and a lower MSA-predicted eating-quality score than did steers. There was no interaction between postweaning growth and sire carcass type. These results indicate that with the use of appropriate sire carcass types and BREEDPLAN, and post-weaning nutrition, beef producers can confidently change carcass parameters to suit market specifications.

scholarly journals Estimation of Genetic Parameters for Pork Quality, Novel Carcass, Primal-Cut and Growth Traits in Duroc Pigs

Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 779 ◽  
Author(s):  
Hannah E. Willson ◽  
Hinayah Rojas de Oliveira ◽  
Allan P. Schinckel ◽  
Daniela Grossi ◽  
Luiz F. Brito
Keyword(s):  
Genetic Parameters ◽  
Growth Traits ◽  
Low Cost ◽  
Selection Index ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Pork Quality ◽  
Production Traits ◽  
Genetic Progress ◽  
Selection Indexes

More recently, swine breeding programs have aimed to include pork quality and novel carcass (e.g., specific primal cuts such as the Boston butt or belly that are not commonly used in selection indexes) and belly traits together with growth, feed efficiency and carcass leanness in the selection indexes of terminal-sire lines, in order to efficiently produce pork with improved quality at a low cost to consumers. In this context, the success of genetic selection for such traits relies on accurate estimates of heritabilities and genetic correlations between traits. The objective of this study was to estimate genetic parameters for 39 traits in Duroc pigs (three growth, eight conventional carcass (commonly measured production traits; e.g., backfat depth), 10 pork quality and 18 novel carcass traits). Phenotypic measurements were collected on 2583 purebred Duroc gilts, and the variance components were estimated using both univariate and bivariate models and REML procedures. Moderate to high heritability estimates were found for most traits, while genetic correlations tended to be low to moderate overall. Moderate to high genetic correlations were found between growth, primal-cuts and novel carcass traits, while low to moderate correlations were found between pork quality and growth and carcass traits. Some genetic antagonisms were observed, but they are of low to moderate magnitude. This indicates that genetic progress can be achieved for all traits when using an adequate selection index.

scholarly journals Feed efficiency and carcass metrics in growing cattle1

2019 ◽  
Vol 97 (11) ◽  
pp. 4405-4417 ◽  
Author(s):  
David N Kelly ◽  
Craig Murphy ◽  
Roy D Sleator ◽  
Michelle M Judge ◽  
Stephen B Conroy ◽  
...  
Keyword(s):  
Feed Efficiency ◽  
Production Efficiency ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Live Weight ◽  
Residual Energy ◽  
Feedlot Cattle ◽  
Carcass Weight ◽  
Research Perspective ◽  
Dressing Percentage

Abstract Some definitions of feed efficiency such as residual energy intake (REI) and residual gain (RG) may not truly reflect production efficiency. The energy sinks used in the derivation of the traits include metabolic live-weight; producers finishing cattle for slaughter are, however, paid on the basis of carcass weight, as opposed to live-weight. The objective of the present study was to explore alternative definitions of REI and RG which are more reflective of production efficiency, and quantify their relationship with performance, ultrasound, and carcass traits across multiple breeds and sexes of cattle. Feed intake and live-weight records were available on 5,172 growing animals, 2,187 of which also had information relating to carcass traits; all animals were fed a concentrate-based diet representative of a feedlot diet. Animal linear mixed models were used to estimate (co)variance components. Heritability estimates for all derived REI traits varied from 0.36 (REICWF; REI using carcass weight and carcass fat as energy sinks) to 0.50 (traditional REI derived with the energy sinks of both live-weight and ADG). The heritability for the RG traits varied from 0.24 to 0.34. Phenotypic correlations among all definitions of the REI traits ranged from 0.90 (REI with REICWF) to 0.99 (traditional REI with REI using metabolic preslaughter live-weight and ADG). All were different (P < 0.001) from one suggesting reranking of animals when using different definitions of REI to identify efficient cattle. The derived RG traits were either weakly or not correlated (P > 0.05) with the ultrasound and carcass traits. Genetic correlations between the REI traits with carcass weight, dressing difference (i.e., live-weight immediately preslaughter minus carcass weight) and dressing percentage (i.e., carcass weight divided by live-weight immediately preslaughter) implies that selection on any of the REI traits will increase carcass weight, lower the dressing difference and increase dressing percentage. Selection on REICW (REI using carcass weight as an energy sink), as opposed to traditional REI, should increase the carcass weight 2.2 times slower but reduce the dressing difference 4.3 times faster. While traditionally defined REI is informative from a research perspective, the ability to convert energy into live-weight gain does not necessarily equate to carcass gain, and as such, traits such as REICW and REICWF provide a better description of production efficiency for feedlot cattle.

scholarly journals Comparison of models for estimating genetic parameters and predicting breeding values for birth weight and calving ease in Czech Charolais cattle 

2014 ◽  
Vol 59 (No. 7) ◽  
pp. 302-309 ◽  
Author(s):  
L. Vostrý ◽  
Z. Veselá ◽  
A. Svitáková ◽  
H. Vostrá Vydrová
Keyword(s):  
Animal Model ◽  
Birth Weight ◽  
Beef Cattle ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Parameters Estimation ◽  
Calving Ease ◽  
Heritability Estimates

The most appropriate model for genetic parameters estimation for calving ease and birth weight in beef cattle was selected. A total of 27 402 field records were available from the Czech Charolais breed. For estimation of genetic parameters for calving ease and body weight, three bivariate models were tested: a linear-linear animal model (L-LM) with calving ease classified into four categories (1 &ndash; easy; 2&ndash;4 &ndash; most difficult), a linear-linear animal model (SC-LM) in which calving ease scores were transformed into Snell scores (Snell 1964) and expressed as percentage of assisted calving (ranging 0&ndash;100%), and a bivariate threshold-linear animal model (T-LM) with calving ease classified into four categories (1 &ndash; easy, 2&ndash;4 &ndash; most difficult). All tested models included fixed effects for contemporary group (herd &times; year &times; season), age of dam, sex and breed of a calf. Random effects included direct and maternal genetic effects, maternal permanent environmental effect, and residual error. Direct heritability estimates for calving ease and birth weight were, with the use of L-LM, SC-LM, and T-LM, from 0.096 &plusmn; 0.013 to 0.226 &plusmn; 0.024 and from 0.210 &plusmn; 0.024 to 0.225 &plusmn; 0.026, respectively. Maternal heritability estimates for calving ease and birth weight were, with the use of L-LM, SC-LM, and T-LM, from 0.060 &plusmn; 0.031 to 0.104 &plusmn; 0.125 and from 0.074 &plusmn; 0.041 to 0.075 &plusmn; 0.040, respectively. Genetic correlations of direct calving ease with direct birth weight ranged from 0.46 &plusmn; 0.06 to 0.50 &plusmn; 0.06 for all tested models; whereas maternal genetic correlations between these two traits ranged from 0.24 &plusmn; 0.17 to 0.25 &plusmn; 0.53. Correlations between direct and maternal genetic effects within-trait were negative and substantial for all tested models (ranging from &ndash;0.574 &plusmn; 0.125 to &ndash;0.680 &plusmn; 0.141 for calving ease and from &ndash;0.553 &plusmn; 0.122 to &ndash;0.558 &plusmn; 0.118 for birth weight, respectively), illustrating the importance of including this parameter in calving ease evaluations. Results indicate that any of the tested models could be used to reliably estimate genetic parameters for calving ease for beef cattle in the Czech Republic. However, because of advantages in computation time and practical considerations, genetic analysis using SC-LM (transformed data) is recommended.

Genetic correlations among indicator traits for carcass composition measured in yearling beef bulls and finished feedlot steers

2005 ◽  
Vol 85 (4) ◽  
pp. 463-473 ◽  
Author(s):  
R. Bergen ◽  
S. P. Miller ◽  
J. W. Wilton
Keyword(s):  
Genetic Correlation ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Carcass Composition ◽  
Carcass Weight ◽  
Muscle Size ◽  
Longissimus Muscle ◽  
Muscle Area ◽  
Feedlot Steers ◽  
Beef Bulls

Genetic correlations were examined among 10 live growth and ultrasound traits measured in yearling beef bulls (n = 2172) and four carcass traits measured in crossbred finished feedlot steers (n = 1031). Heritabilities ranged from 0.13 (bull ultrasound longissimus muscle width) to 0.83 (yearling bull hip height). Genetic correlations indicated that selecting yearling bulls for increased growth rate and hip height would lead to higher carcass weight, increased longissimus muscle area and reduced levels of carcass marbling in steers. Bull ultrasound fat depth was positively associated with both carcass fat depth and marbling score. Most ultrasound longissimus muscle size measurements in bulls were positively associated with each other and with carcass longissimus muscle area in steers, but the magnitude of the genetic correlation with carcass measurements depended on the bull longissimus muscle size trait in question. This suggests that longissimus muscle shape in bulls may be related to carcass weight, fat and muscle traits in steers. Results confirm that while ultrasound is a valuable tool for the genetic improvement of carcass traits in beef cattle, genetic correlations between live bull ultrasound and steer carcass traits less then unity suggest that selection would benefit from multiple trait evaluations in situations where reliable carcass data are available. Key words: Ultrasound, beef carcass, heritability, genetic correlation

Genetic parameters among growth and carcass traits of Canadian Charolais cattle

2004 ◽  
Vol 84 (4) ◽  
pp. 589-597 ◽  
Author(s):  
D. H. Crews ◽  
Jr., M. Lowerison ◽  
N. Caron ◽  
R. A. Kemp
Keyword(s):  
Fixed Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Subcutaneous Fat ◽  
Field Performance ◽  
Pedigree Data ◽  
Marbling Score ◽  
Muscle Area

Genetic parameters for three growth and five carcass traits were estimated for Charolais using a combination of carcass progeny test, purebred field performance and pedigree data. Heritabilities and genetic and residual correlations were derived from variance components for birth weight (BWT, n = 54 221), 205-d weaning weight (WT205, n = 31 384), postweaning gain (PWG, n = 19 403), hot carcass weight (HCW, n = 6958), average subcutaneous fat thickness (FAT, n = 6866), longissimus muscle area (REA, n = 6863), marbling score (MAR, n = 6903) and estimated carcass lean yield percentage (PLY, n = 6852) with an animal model (n = 78 728) and restricted maximum likelihood. Breed of dam and contemporary group appropriate to each trait were included as fixed effects in the model, whereas random effects included direct genetic for all traits, maternal genetic for BWT and WT205, and maternal permanent environmental for WT205. Carcass traits were adjusted to a constant harvest age of 425 d. Heritability estimates of 0.53, 0.22, and 0.21 were obtained for direct components of BWT, WT205, and PWG, respectively, and maternal heritabilities were 0.16 and 0.10 for BWT and WT205, respectively. Direct × maternal genetic correlations for BWT (-0.49) and WT205 (-0.35) were negative. Heritabilities for HCW, FAT, REA, MAR, and PLY were 0.33, 0.39, 0.43, 0.34, and 0.46, respectively. Genetic correlations among direct effects for growth traits were moderately positive and generally uncorrelated with maternal effects across traits. Lean and fat deposition in the carcass generally had negative, unfavorable genetic correlations, although improvement in lean yield and marbling score may not be strongly antagonistic. Genetic correlations of direct and maternal components of growth traits with carcass traits suggested that selection for increased growth rate would not be antagonistic to improvement in carcass yield or meat quality. Key words: Carcass, Charolais, correlation, genetic parameters, growth

ESTIMATES OF GENETIC CORRELATIONS AMONG CERTAIN CARCASS AND PERFORMANCE TRAITS IN SWINE

1968 ◽  
Vol 48 (1) ◽  
pp. 1-6 ◽  
Author(s):  
G. L. Roy ◽  
W. J. Boylan ◽  
M. E. Seale
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Genetic Relationships ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Development Project ◽  
Carcass Trait ◽  
Selection For ◽  
And Performance ◽  
Daily Gain

Data from a swine breed development project provided estimates of the genetic correlation among six performance and carcass traits. The data from the new breed, called Managra, were obtained over a 7-year period. Most genetic relationships examined were such that selection for improvement of one trait would yield a favorable improvement in another. Both carcass backfat and live backfat probe were found to be negatively correlated with area of loin eye and length of carcass. A positive genetic correlation was found between post-weaning daily gain and loin eye area. A high positive genetic correlation was found between birth weight and loin eye area. An unfavorable association involved a positive genetic correlation between birth weight and backfat.Correction factors for effect of carcass weight on the magnitude of carcass trait measurements and differences in means between sexes were obtained.Heritability of the traits was estimated by paternal half-sib correlation. The estimates for carcass traits were moderately high and agree well with most other estimates reported in the literature.

scholarly journals Analysis of non-genetic and genetic influences underlying the growth of Kajli lambs

2020 ◽  
Vol 50 (4) ◽  
pp. 613-625
Author(s):  
A. Ali ◽  
K. Javed ◽  
I. Zahoor ◽  
K.M. Anjum
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Fixed Effects ◽  
Genetic Correlations ◽  
Breeding Value ◽  
Season Of Birth ◽  
Genetic Trend ◽  
Breeding Values ◽  
Heritability Estimates ◽  
Birth Type

Data on 2931 Kajli lambs, born from 2007 to 2018, were used to quantify environmental and genetic effects on growth performance of Kajli sheep. Traits considered for evaluation were birth weight (BWT), 120-day adjusted weight (120DWT), 180-day adjusted weight (180DWT), 270-day adjusted weight (270DWT), and 365-day adjusted weight (365DWT). Fixed effects of year of birth, season of birth, sex, birth type, and dam age on these traits were evaluated using linear procedures of SAS, 9.1. Similarly, BWT, 120DWT, 180DWT, and 270DWT were used as fixed effects mixed model analyses. Variance components, heritability and breeding values were estimated by restricted maximum likelihood. The genetic trend for each trait was obtained by regression of the estimated breeding values (EBV) on year of birth. Analyses revealed substantial influence of birth year on all traits. Sex and birth type were the significant sources of variation for BWT and 120DWT. Season of birth did not influence birth weight meaningfully, but had a significant role in the expression of 120DWT, 180DWT, and 270DWT. Heritability estimates were generally low (0.003 ± 0.018 to 0.099 ± 0.067) for all traits. With the exception of the genetic correlation of 180DWT and 365DWT, the genetic correlations between trait were strong and positive. Only 365DWT had a positive genetic trend. Although the heritability estimates for almost all weight traits were low, high and positive genetic correlations between BWT and other weight traits suggest that selection based on BWT would result in the improvement of other weight traits as a correlated response.Keywords: bodyweight, breeding value, genetic correlation, sheep

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