The Effect of Crossbreeding on Some Economic Traits for Chicks of Lohmann Chicken

2020 ◽  
Vol 10 (1) ◽  
pp. 221-226
Author(s):  
Allawi Luaibi Dagher Al-Khauzai
Keyword(s):  
Weight Gain ◽  
Genetic Correlation ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Animal Production ◽  
Daily Weight Gain ◽  
Feed Ratio ◽  
Poultry Farm ◽  
Economic Traits ◽  
College Of Agriculture

The experiment has been conducted at the poultry farm of Al-Qadisyah University, College of Agriculture, Department of Animal Production , for  the period 24/11/2018 till 10/4/2019 by using  80 hatching chicks which belong to 20 dams and 5 sires, each sire includes 16 chicks. Four chickens are put  with each sire, the first sire( Leghorn) crossbreeding with dams of Lohmann , the remaining sires are local cocks ,with five Lohmann hens. The chicks of each sire divided into two replicates ,each  replicate contains 8 chicks , the experiment continues for 42 days of age. The experiment aims to study the effect of sire groups on growth traits (weight at hatching , weight at 42 days of age , weight gain and daily weight gain ) Also , the effect of sire on weekly consumption feed , in addition to estimate the heritability for previous traits and the genetic correlations among these traits. The results can be summarized as follows : The overall means of weight at hatching , weigh at 42 days of age , weight gain and daily weight gain are 34.572 , 354.898 , 320.327 and 7.627 gm respectively , the sire groups appear significantly (p<05) effect on weight at hatching and weight at 42 days of age and weekly consumption seeds. Sex has significantly (p<05) effect on weight at hatching and weight at 42 days of age. The conversion feed ratio is 3.462 gm consume feed/ gm of meat. The estimated values of heritability for weight at hatching weight at 42 days of age , weight gain and daily weight gain and daily weight gain , are 0.332 , 0.55 , 0.55 and 0.56 respectively. The values of genetic correlation between weight at hatching and weight at 42 days of age and between weight at hatching and weight gain are 0.98 and 0.58 respectively.

Breeding for improved growth and juvenile corewood stiffness in slash pine

2007 ◽  
Vol 37 (10) ◽  
pp. 1886-1893 ◽  
Author(s):  
Xiaobo Li ◽  
Dudley A. Huber ◽  
Gregory L. Powell ◽  
Timothy L. White ◽  
Gary F. Peter
Keyword(s):  
Genetic Correlation ◽  
Growth Traits ◽  
Low Cost ◽  
Genetic Correlations ◽  
Volume Growth ◽  
Pinus Elliottii ◽  
Tree Improvement ◽  
Slash Pine ◽  
Narrow Sense Heritability ◽  
Improvement Programs

The importance of integrating measures of juvenile corewood mechanical properties, modulus of elasticity in particular, with growth and disease resistance in tree improvement programs has increased. We investigated the utility of in-tree velocity stiffness measurements to estimate the genetic control of corewood stiffness and to select for trees with superior growth and stiffness in a progeny trial of 139 families of slash pine, Pinus elliottii Engelm. grown on six sites. Narrow-sense heritability estimates across all six sites for in-tree acoustic velocity stiffness at 8 years (0.42) were higher than observed for height (0.36) and diameter at breast height (DBH) (0.28) at 5 years. The overall type B genetic correlation across sites for velocity stiffness was 0.68, comparable to those found for DBH and volume growth, indicating that family rankings were moderately repeatable across all sites for these traits. No significant genetic correlations were observed between velocity stiffness, DBH, and volume growth. In contrast, a significant, but small, favorable genetic correlation was found between height and velocity stiffness. Twenty percent of the families had positive breeding values for both velocity stiffness and growth. The low cost, high heritability and nearly independent segregation of the genes involved with in-tree velocity stiffness and growth traits indicate that acoustic methods can be integrated into tree improvement programs to breed for improved corewood stiffness along with growth in slash pine.

scholarly journals Photoperiod on growth and egg characteristics of the white leghorn chicken

2021 ◽  
Vol 15 (1) ◽  
pp. 151-155
Author(s):  
Abdul Muumin Sadick ◽  
Iddrisu Mubarik ◽  
Dennis Kodzo Awalime ◽  
Rebecca Akumbilim ◽  
Philip Larweh ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Feed Intake ◽  
Growth Traits ◽  
Growth Parameters ◽  
Skills Training ◽  
Daily Weight Gain ◽  
White Leghorn ◽  
Initial Body Weight ◽  
Final Body Weight

One hundred and twenty (120) 16 weeks old White Leghorn layer breeds were used for the study. The objective of the study was to determine effect of photoperiod on layer chicken. The research was carried out at the Poultry Section of the Animal farm of the Department of Animal Science Education, Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development, Mampong. Four treatments made up of 12 hours of light, 14 hours of light, 16 hours of light and 18 hours of light were used for the study. Each treatment was replicated three times with 10 birds per replicate in a Completely Randomized Design. Birds were exposed equally to common daylight and in the evenings, lights were turned on at specified periods. Growth parameters measured were initial body weight, daily feed intake, daily weight gain and final body weight. Egg traits measured were egg weight, albumen height, yolk color and yolk weight. The data collected were analyzed using General Linear Model procedure of Statistical Analysis System. Results from the study indicated that, varied photoperiod regimes had no significant (P>0.05) effect on initial body weight, daily feed intake but had significant (P<0.05) effect on daily weight gain and final body weight of growth traits. Photoperiod had no significant (P>0.05) effect on the egg characteristics of the white Leghorn layer bird. It was concluded from the study that, increasing photoperiod had no positive effect on growth and egg characteristics of the white Leghorn layer.

scholarly journals Genetic-Quantitative Uni- and Bi-Trait Analysis for Growth Traits in the Colombian Creole Breed Blanco Orejinegro (BON)

2021 ◽  
Author(s):  
Marisol Londoño-Gil ◽  
Juan Carlos Rincón Flórez ◽  
Albeiro López-Herrera ◽  
Luis Gabriel Gonzalez-Herrera
Keyword(s):  
Growth Traits ◽  
Genetic Correlations ◽  
Genetic Effect ◽  
Cattle Breed ◽  
Live Weight ◽  
Daily Weight Gain ◽  
Additive Genetic Effect ◽  
Selection Processes ◽  
Heritability Estimates ◽  
Maternal Heritability

Abstract The Blanco Orejinegro (BON) is a Colombian creole cattle breed that is not genetically well characterized for growth traits. The aim of this work was to estimate genetic parameters for birth weight (BW), weaning weight (WW), yearling weight (YW), daily weight gain between birth and weaning (DWG), time to reach 120 kg of live weight (T120), and time to reach 60% of adult weight (T60%), and establish the selection criteria for growth traits in the BON population of Colombia. Genealogical and phenotypic information for BW, WW, YW, DWG, T120, and T60% traits of BON animals from 14 Colombian herds were used. These traits were analyzed with the AIREML method in a uni- and bi-trait animal model including the maternal effect for BW, WW, DWG, and T120. The direct heritability estimates values were 0.22 ± 0.059 (BW), 0.20 ± 0.057 (WW), 0.20 ± 0.153 (YW), 0.17 ± 0.07 (DWG), 0.26 (T120), and 0.44 ± 0.03 (T60%). The maternal heritability estimates values were 0.14 ± 0.040 (BW), 0.15 ± 0.039 (WW), 0.25 ± 0.06 (DWG), and 0.16 (T120). The direct genetic correlations were high (>|0.60|) among all the traits, except between T60% with BW, WW, YW, and DWG (ranged from -0.02 to -0.51), all in a favorable direction. The results showed that there is genetic variation in the growth traits associated with the additive genetic effect and they might respond to selection processes. Furthermore, genetic gains would improve through selection, especially for YW and T60% when WW is used as criterion.

scholarly journals Genetics of adaptive traits in heifers and their relationship to growth, pubertal and carcass traits in two tropical beef cattle genotypes

2009 ◽  
Vol 49 (6) ◽  
pp. 413 ◽  
Author(s):  
K. C. Prayaga ◽  
N. J. Corbet ◽  
D. J. Johnston ◽  
M. L. Wolcott ◽  
G. Fordyce ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Genetic Correlation ◽  
Genetic Association ◽  
Body Condition Score ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Coat Colour ◽  
Economic Traits ◽  
Adaptive Traits ◽  
Condition Score

Genetic analyses of tropical adaptive traits were conducted for two tropically adapted genotypes, Brahman (BRAH) and Tropical Composite (TCOMP). Traits included tick scores (TICK), faecal egg counts (EPG), buffalo fly-lesion scores (FLY), rectal temperatures under hot conditions (TEMP), coat scores (COAT), coat colour on a light to dark scale (COLOUR), navel scores (NAVEL) and temperament measured as flight time (FT). The data comprised adaptive measures recorded at specific times on 2071 heifers comprising 966 BRAH and 1105 TCOMP. The genetic correlations of these adaptive traits with heifer growth, scanned carcass, pubertal measures and steer growth and carcass traits were estimated. BRAH recorded significantly (P < 0.05) lower TICK, EPG, FLY and TEMP than did TCOMP. BRAH also had significantly sleeker coats, lighter coat colour, more pendulous navels and more docile temperament than did TCOMP. The heritability of TICK and FLY was low (<20%), that of EPG, TEMP, NAVEL and FT was moderate (20–50%) and that of COAT and COLOUR high (>50%). In general, phenotypic correlations between these adaptive traits were low and genetic correlations were non-significant, implying trait independence. Genetic correlations between EPG and weight traits (0.29 to 0.44) indicated a positive relationship, implying no deleterious effect of worms on the growth at a genetic level, especially in TCOMP. The negative genetic correlations between COAT and body-condition score across genotypes (–0.33 to –0.48) indicated genetic advantage of sleek coats in tropics. A positive genetic correlation between COAT and the age at the first-observed corpus luteum (0.73) in BRAH indicated that BRAH with sleeker coats were genetically early maturing. Further, sleeker coats were genetically indicative of lower weights and lower fat cover at puberty in BRAH. The scanned fat measures at rump and rib sites for feedlot steers showed strong genetic correlation (0.50–0.58) with heifer TEMP, indicating genetically fatter animals had genetically lower heat tolerance. In BRAH, a positive genetic association between heifer COLOUR and scanned fat measures in steers (0.50–0.54) implied increased fatness in genetically darker animals. Further, in BRAH, a strong negative genetic correlation (–0.97) was observed between steer retail beef yield and heifer TEMP, indicating a favourable genetic association. In general, genetic correlations between adaptive traits and other economic traits were genotype specific. Further, it can be concluded that selection for productive and pubertal traits in tropical beef cattle genotypes would not adversely affect their tropical adaptability.

Genetic parameters for daily live-weight gain, live fleshiness and bone thinness in station-tested Piemontese young bulls

2001 ◽  
Vol 72 (3) ◽  
pp. 449-456 ◽  
Author(s):  
A. Albera ◽  
R. Mantovani ◽  
G. Bittante ◽  
A. F. Groen ◽  
P. Carnier
Keyword(s):  
Weight Gain ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Live Weight ◽  
Adaptation Period ◽  
Production Traits ◽  
Multiple Trait ◽  
Live Weight Gain ◽  
Total Gain

AbstractEstimates of genetic parameters for beef production traits were obtained for Piemontese cattle. Data were from 988 young bulls station-tested from 1989 till 1998. Bulls entered the station at 6 to 8 weeks of age and, after an adaptation period of 3 months, were tested for growth, live fleshiness and bone thinness. Length of test was 196 days. Growth traits considered were gain at farm, gain during the adaptation period, gain on test and total gain at the station. Six different fleshiness traits and bone thinness were scored on live animals at the end of the test using a linear system. Live evaluations of fleshiness were adjusted for the weight at scoring in order to provide an assessment of conformation independent of body size. Genetic parameters were estimated using animal models. Heritability of live-weight gain ranged from 0·20 in the adaptation period to 0·60 for total gain at the station. Genetic correlations between gains at station in different periods were high (from 0·63 to 0·97). Residual correlation between gain during the adaptation period and gain during test was negative, probably due to the occurrence of compensatory growth of the animals.Live fleshiness traits and bone thinness were of moderate to high heritability (from 0·34 to 0·55) and highly correlated indicating that heavy muscled bulls also have thin bones. Accuracy of breeding values and therefore response to selection were improved by multiple trait analysis of the live fleshiness traits and bone thinness. Overall weight gain at the station had a moderate negative genetic correlation with all live fleshiness traits and bone thinness (from –0·11 to –0·39).

scholarly journals 209 Genomic selection for multiple maternal and growth traits in large white pigs using Single-Step GBLUP

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 42-42
Author(s):  
Breno Fragomeni ◽  
Zulma Vitezica ◽  
Justine Liu ◽  
Yijian Huang ◽  
Kent Gray ◽  
...  
Keyword(s):  
Genetic Correlation ◽  
Growth Traits ◽  
Computing Time ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Single Step ◽  
Genomic Information ◽  
Genomic Evaluation ◽  
Large White ◽  
Daily Gain

Abstract The objective of this study was to implement a multi-trait genomic evaluation for maternal and growth traits in a swine population. Phenotypes for preweaning mortality, litter size, weaning weight, and average daily gain were available for 282K Large White pigs. The pedigree included 314k individuals, of which 35,731 were genotyped for 45K SNPs. Variance components were estimated in a multi-trait animal model without genomic information by AIREMLF90. Genomic breeding values were estimated using the genomic information by single-step GBLUP. The algorithm for proven and young (APY) was used to reduce computing time. Genetic correlation between proportion and the total number of preweaning deaths was 0.95. A strong, positive genetic correlation was also observed between weaning weight and average daily gain (r = 0.94). Conversely, the genetic correlations between mortality and growth traits were negative, with an average of -0.7. To avoid computations by expensive threshold models, preweaning mortality was transformed from a binary trait to two linear dam traits: proportion and a total number of piglets dead before weaning. Because of the high genetic correlations within groups of traits, inclusion of only one growth and one mortality trait in the model decreases computing time and allows for the inclusion of other traits. Reduction in computing time for the evaluation using APY was up to 20x, and no differences in EPD ranking were observed. The algorithm for proven and young improves the efficiency of genomic evaluation in swine without harming the quality of predictions. For this population, a binary trait of mortality can be replaced by a linear trait of the dam, resulting in a similar ranking for the selection candidates.

Genetic relationships between seasonal tissue levels in Scottish Blackface ewes and lamb growth traits

2005 ◽  
Vol 81 (1) ◽  
pp. 11-21 ◽  
Author(s):  
N. R. Lambe ◽  
S. Brotherstone ◽  
M. J. Young ◽  
J. Conington ◽  
G. Simm
Keyword(s):  
Weight Gain ◽  
Birth Weight ◽  
Litter Size ◽  
Growth Traits ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Muscle Weight ◽  
Litter Weight ◽  
Weight Gains ◽  
Lamb Growth

AbstractScottish Blackface ewes (no. = 308) were scanned four times per year using X-ray computed tomography (CT scanning) (pre-mating, pre-lambing, mid lactation and weaning), from 18 months to 5 years of age, giving a maximum of 16 scanning events per ewe. Total weights of carcass fat, internal fat and carcass muscle were estimated from the CT images at each scanning event. Lambs produced by these ewes were weighed at birth, mid lactation and weaning to calculate litter growth traits: litter birth weight; litter weight gain from birth until mid lactation; and litter weight gain from birth until weaning. Genetic (rg) and phenotypic (rp) correlations were estimated between ewe CT tissue traits and litter growth traits. Correlations between ewe CT tissue traits and litter size (LS) were also estimated. Ewe CT tissue traits were either unadjusted or adjusted for total soft tissue weight (sum of weights of carcass fat, internal fat and carcass muscle) to investigate relationships with either absolute tissue weights of carcass fat (CFWT), internal fat (IFWT), and carcass muscle (CMWT), or relative proportions of carcass fat (CFP), internal fat (IFP), and carcass muscle (CMP). Litter growth traits were either unadjusted or adjusted for litter size, to investigate relationships with total lamb burden (total litter birth weight (TBW), total litter weight gain from birth until mid lactation (TWGM), total litter weight gain from birth until weaning (TWGW)) or average lamb performance (average lamb birth weight (ABW), average lamb weight gain from birth until mid lactation (AWGM), average lamb weight gain from birth until weaning (AWGW)).Moderate to large positive genetic correlations were estimated between absolute weights of all three ewe tissues (CFWT, IFWT, CMWT), or muscle proportion (CMP), and litter size (LS). Significant positive genetic correlations were also estimated between weight (CMWT) or proportion (CMP) of muscle carried by the ewe pre-mating and total birth weight (TBW) and weight gains (TWGM, TWGW) of her litter, largely due to the associated increase in litter size. Muscle proportion (CMP) was not significantly correlated to average lamb weights or weight gains (ABW, AWGM, AWGW). Pre-lambing carcass fat weight (CFWT) and proportion (CFP) in the ewe showed positive genetic correlations with average lamb weights and weight gains (ABW, AWGM, AWGW), whereas, after lambing, CFP was negatively correlated with these lamb traits. Internal fat weight (IFWT) pre-mating showed positive genetic correlations with all litter growth traits (TBW, TWGM, TWGW, ABW, AWGM, AWGW). Average lamb growth traits were negatively correlated with pre-lambing internal fat proportion (IFP), but positively correlated to IFP at mid lactation and weaning.Correlations were also estimated between each pair of CT traits. Total internal fat weight and total carcass fat weight were very highly correlated (rp= 0·75,rg= 0·96). Correlations with total carcass muscle weight were smaller and positive for both carcass fat weight (rp= 0·48,rg= 0·12) and internal fat weight (rp= 0·42,rg= 0·20).The results suggest that selection for increased carcass muscle weight or proportion in a Scottish Blackface hill flock would have a positive effect on total weights of litters reared, but that selection against carcass fat weight or proportion in a breeding programme for Blackface sheep may have an impact on the maternal ability of the ewe. However, maintaining fat in internal depots may reduce the depletion of carcass fat during pregnancy, allowing this depot to provide energy for lactation, and may have a positive impact on lamb growth.

scholarly journals On-farm evaluation of growth and reproductive performances of Washera and Gumuz sheep in northwestern Ethiopia: Basics for setting up breeding objectives/goals

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254924
Author(s):  
Sisay Asmare ◽  
Kefyalew Alemayehu ◽  
Solomon Abegaz ◽  
Aynalem Haile
Keyword(s):  
Weight Gain ◽  
Reproductive Performance ◽  
Interaction Effect ◽  
Growth Traits ◽  
Live Weight ◽  
Daily Weight Gain ◽  
Average Daily Weight Gain ◽  
Breed Type ◽  
Breeding Objectives ◽  
Performance Traits

Growth and reproductive performance traits are traits of economic importance for sheep selection and productivity improvement interventions. This study aimed at comparative evaluation of growth and reproductive performance traits of sheep in the highland and lowland agro-ecologies of northwestern Ethiopia. Data on growth performance traits were collected from 144 Washera (78 males and 66 females) lambs and 72 Gumuz (37 males and 35 females) lambs. Data on reproductive performance traits were collected from 260 Washera (130 rams and 130 ewes) sheep and 150 Gumuz (75 rams and 75 ewes) sheep. General linear model univariate procedure was employed to analyze the collected data. Breed, the interaction effect between breed and season of birth as well as the interaction effect between breed and type of birth all exerted very high significant effect (P<0.001) on live weight at all age groups. Breed type affected pre-weaning average daily weight gain significantly (P<0.01). Pre-weaning average daily weight gain of Washera (70 g/day) was found much better performance than 60 g/day of Gumuz. Breed type exerts significant (P<0.05) effect on age at first lambing, lambing interval, annual reproductive rate and number of lambs born per ewe life time. Average age at first lambing and lambing interval of Washera sheep were 11.69 months and 9.27 months, respectively. The corresponding values for Gumuz sheep were 12.51 months and 10.43 months, respectively. Production and reproduction performance values of traits varied across the two breeds and sexes as well. These values can be used to set up breeding objectives or goals for selective breeding of sheep giving special emphasis to growth traits believed to have medium heritability values.

scholarly journals PSVIII-36 Polymorphisms at the 5’ region flanking the ovine IGF-1 gene affect mRNA levels in dorper lambs

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 267-268
Author(s):  
Luis Angel Flores Encinas ◽  
José alfredo Martínez Quintana ◽  
Felipe Alonso rodriguez almeida ◽  
Monserrath Felix-Portillo ◽  
Francisco Joel Jahuey Martínez
Keyword(s):  
Gene Expression ◽  
Weight Gain ◽  
Muscle Development ◽  
Growth Traits ◽  
Marker Gene ◽  
Farm Animals ◽  
Daily Weight Gain ◽  
Second Phase ◽  
Mrna Levels ◽  
Phenotypic Characteristics

Abstract The insulin-like growth factor-1 (IGF-1) plays a key role in muscle development and has been described in several studies as a candidate marker gene for growth traits in farm animals. The aim of the study was to investigate IGF-1 single nucleotide polymorphisms (SNPs) at the 5’ flanking region and their association with gene expression levels and phenotypic characteristics in lambs. The experiment was executed in two phases. First, a 265 bp-long region of gDNA localized up-stream of the IGF-1 gene was scanned for SNPs by sequencing. Sequence analysis revealed that animals with low IGF-1 plasm concentration had nucleotide changes from Guanine (G) to Cytosine (C) at position 85 (85G &gt;C), and from G to Adenine (A) at position 87 (87G &gt;A). A PCR-RFLP protocol was set up to accomplish allelic discrimination in 22 lambs sired by Dorper rams. The frequency of the variant-carrier lambs was 50 %. The statistical analysis showed differences (P &lt; 0.05) between carrier and non-carrier female lambs for IGF-1 concentration at 13 d (168.76 ± 15.01 vs 229.95 ± 16.78), 41 d (191.02 ± 38.28 vs 324.50 ± 42.80) and 69 d (209.18 ± 30.63 vs 375.87 ± 34.2) of the feeding trial. Statistical differences (P &lt; 0.05) were also found for total weight gain (22.16 ± 1.07 vs 26.75 ± 1.2). In a second phase, 55 Dorper females were genotyped, then 2 homozygotes, 5 heterozygotes and 5 wild-type for the variant were randomly selected for IGF-1 qPCR gene expression analysis. Gene expression was higher (fold-change 2.6) in non-carrier animals (P &lt; 0.05). Nevertheless, daily weight gain and weight at 150 d were not statistically significant. The variant for the IGF-1 gene here reported has lower levels of gene expression. However, additional experiments are needed to measure phenotypic characteristics such as carcass traits, diameter and density of muscle fibers.

Genetic correlation between growth and reproductive performance of beef females depends on environment

2018 ◽  
Vol 58 (7) ◽  
pp. 1201 ◽  
Author(s):  
Mário L. Santana Jr ◽  
Joanir P. Eler ◽  
Annaiza B. Bignardi ◽  
Arione A. Boligon ◽  
José B. S. Ferraz
Keyword(s):  
Beef Cattle ◽  
Genetic Correlation ◽  
Reproductive Performance ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Random Regression ◽  
Tropical Region ◽  
Correlated Response ◽  
Heterogeneous Environments ◽  
Environment Interaction

In tropical production systems, beef cattle are raised in highly heterogeneous environments. Heterogeneity is, therefore, expected to exist in the (co)variance components for traits of economic interest in different production environments. The main objective of the present study was to estimate genetic correlations between growth traits and reproductive performance of beef females, depending on the environment. The present study was conducted in the tropical region of Brazil, applying a multiple-trait random regression animal model to field records of heifer pregnancy (HP), hip height, bodyweight at ~18 months of age (BW18) and postweaning weight gain (PWG) from 20 893 Nelore females. As evidence of genotype by environment interaction (G × E), heterogeneity of genetic variance across environments was observed mainly for HP, PWG and BW18. Moreover, the estimates of genetic correlation within these traits reached values lower than unity on the environmental gradient. The genetic correlation among growth traits tended to be stronger in favourable environments, a fact that should favour correlated responses under these conditions. In contrast, the genetic correlations between growth traits and HP tended to become weaker and even exhibited little evidence of antagonism in more favourable environments. On the basis of these findings, selection for higher growth in extreme favourable environments should result in little or no damage to HP as a correlated response. All these results lead us to believe that the G × E is an important factor to be considered in genetic evaluations of beef cattle raised in tropical environments.

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