Estimation of Genetic Traits and Factors Affecting Growth in Surti Goats

The present investigation was undertaken to study the interrelationships among morphometric traits, body weight, age and body condition score (BCS) in Surti goats. A total of 200 Surti goats of different age groups were evaluated for body length, height at withers, heart girth, paunch girth, body weight and body condition score assessed at lumbar (BCS-L), rib (BCS-R) and sternum (BCS-S) regions. Pearson’s correlation coefficients were estimated to determine the strength and direction of associations among the studied traits. The results revealed strong and statistically significant (P < 0.01) positive correlations among all linear body measurements, indicating their interdependence. Body weight showed a highly significant correlation with body length (r = 0.80) and height at withers (r = 0.75), while moderate correlations were observed with heart girth and paunch girth. Age exhibited a strong positive association with all morphometric traits, suggesting proportional growth with advancing age. Body condition score was significantly correlated with both body measurements and body weight, with the highest correlation observed between body weight and BCS-L (r = 0.92). Strong inter-correlations were also observed among different BCS assessment sites. These findings indicate that morphometric traits and BCS can serve as reliable, non-invasive indicators for estimating body weight, growth and nutritional status in Surti goats, thereby supporting their use in field-level selection and management practices.

The present work was conducted to evaluate the performance in respect of post-weaning growth and morphometric traits of Assam Hill goat. Data on 960 animals belonging to 3 populations of Assam Hill goat maintained at three field units viz., Batabari, Nahira and Tetelia under All India Coordinated Research Project on Goat Improvement were utilized. The least-squares means for body weight, height at withers, heart girth and body length were 7.557 ± 0.049 kg, 41.231 ± 0.121 cm, 44.621 ± 0.115 cm and 50.778 ± 0.172 cm at 6 months; 9.934 ± 0.044 kg, 43.902 ± 0.120 cm, 48.890 ± 0.099 cm and 55.552 ± 0.170 cm at 9 months and 12.549 ± 0.046 kg, 46.791 ± 0.112 cm, 52.765 ± 0.090 cm and 58.392 ± 0.207 cm at 12 months of age, respectively. Location had significant effect on body weight and height at withers at all age groups; on heart girth at 6, 9 and 12 months and on body length at 6 and 12 months of age. Season of birth exerted significant effect on body weight at 9 and 12 months; on height at withers at 12 months and on body length at 6, 9 and 12 months of age. Significant effect of sex was observed on body weight at 9 and 12 months, on height at withers at 6, 9 and 12 months and on heart girth and body length at 9 and 12 months of age. The heritability estimates for body weight and body measurements were moderate indicating scope of selection. The phenotypic and genetic correlation among body weights and body measurements at 6, 9 and 12 months of age were positive in direction and high in magnitude.

Barbari is most preferred goat breed of commercial farmers in India and information on its first parity growth, reproduction and production traits are valuable for making present and future genetic progress of flock. Data for present study pertains to 2,554 kids, progeny of 227 sires and 1645 dam born during 2001 to 2019 at Central Institute for Research on Goats, Makhdoom, Mathura, Uttar Pradesh. The least squares means of body weight of kids at birth, 3, 6, 9 and 12 months of age were 1.69±0.02, 7.48±0.13, 11.45±0.21, 16.08±0.28 and 20.21±0.33 kg, respectively. Period, sex, type of birth, and weight of dam at kidding were significant sources of non-genetic variation affecting body weights. The least squares mean of weight at first conception, weight at first kidding, age at first conception, age at first kidding and first gestation period were 18.04±0.07 kg, 21.79±0.09 kg, 381.65±2.51 days, 523.23±2.52 days and 143.33±0.21 days, respectively. Period of birth was major source of variation though these traits were also significantly affected by season and type of birth. The least squares means of first lactation 90-days milk yield, 140-days milk yield, total Lactation period milk yield, first lactation Length, milk yield per day of first lactation length and milk yield per day of first kidding interval were 50.22±0.41 litre, 69.94±1.05 litre, 57.32±0.53 litre, 123.01±0.53 days, 48.91±0.35 litre and 19.39±0.22 litres, respectively. Period, season, type of kidding, age and weight of dam at kidding were significant sources of non-genetic variation affecting above lactation traits. The h2 for growth and production traits were moderate whereas low to moderate for reproductive traits except weight at first conception and kidding which have moderate h2 estimates. The genetic and phenotypic correlations among the growth traits at different ages were moderate to high (0.3 to 0.8), however decrease with distant ages. Very high genetic and phenotypic correlation estimates were obtained among lactation traits suggesting that judicious selection of animals' for any lactation traits would yield consistent genetic improvement in the other milk production traits in the flock. The economic traits which were significantly influenced by non-genetic factors with high magnitude need attention for strategic management interventions such as planned breeding of females to avoid kidding in adverse weather conditions, better attention in suckling of milk for kids born with low birth weight, hygiene of shed, adequate supplementation of concentrate ration to those kids which have less pre-weaning growth regardless of type of birth, better nutrition level to maiden goats before and after mating and extension of weaning age for triplets by 10-15 days to obtain higher post weaning weight gains, optimization of breeding weight at first mating and strategic supplementary concentrate feeding as per milk yield.

As a dual-purpose (meat and fat) coarse-wool sheep breed in Xinjiang, the Pishan Red sheep exhibits year-round estrus and excellent reproductive performance. The aim of this study was to systematically estimate the genetic parameters of growth traits in Pishan Red sheep at each stage from 0 to 12 months of age, and to provide a scientific basis for optimizing early selection indices for this breed. Year of birth, type of birth, and sex were included as fixed effects, while maternal genetic effects and individual additive genetic effects were treated as random effects. A multi-trait animal model was constructed using DMU software to analyze the genetic parameters. The results showed that for growth traits at 0 months of age, heritability ranged from 0.09 to 0.64, genetic correlations from -0.03 to 0.84, and phenotypic correlations from 8.2 × 10-3 to 0.32. Among these, the direct heritability of body weight was 0.18, and the maternal heritability was 0.21, while cannon circumference was identified as a high-heritability trait. At 2 months of age, heritability ranged from 0.04 to 0.69, genetic correlations from -0.78 to 0.96, and phenotypic correlations from 0.036 to 0.44. Body weight, body length, and cannon circumference were high-heritability traits. At 6 months of age, heritability ranged from 0.04 to 0.71, genetic correlations from -0.32 to 0.70, and phenotypic correlations from -0.13 to 0.54. Body weight was a medium-heritability trait, while chest width and cannon circumference were high-heritability traits. At 12 months of age, heritability ranged from 0.07 to 0.48, genetic correlations from -0.04 to 0.87, and phenotypic correlations from 0.28 to 0.72. Body weight was a medium-heritability trait, whereas body height, body length, cannon circumference, and heart girth were high-heritability traits. Both body weight and cannon circumference exhibited high heritability throughout the 0-12 month period and can therefore serve as key selection indices for early breeding in this breed. The findings of this study provide essential local baseline data for the genetic improvement, breeding program design, and genetic evaluation of Pishan Red sheep.

The aim of the current study was to estimate the genetic parameters for growth and survival tolerance traits in Litopenaeus vannamei at different ages (weeks 6, 10, 14, and 18). Sixty-five full-sib families (including 30 half-sib families) of L. vannamei, which were produced by 50 sires and 65 dams, were obtained by artificial insemination. There were a total of 6500 tagged shrimps representing 65 full-sib families evaluated for growth and survival traits in this study. The heritability estimates for growth traits were moderate to high (0.24 to 0.46), which suggested that selection for increasing growth traits were feasible, but the heritability of survival traits estimated on the observed scales were also low (0.01 to 0.06). The genetic correlations between growth traits (including body length and weight) within age were all positive and high, which ranged from 0.82 to 0.95 (P < 0.01). A significant correlation between growth traits showed that only selecting one growth trait for better growth and other correlated traits can be improved simultaneously. The genetic correlation between growth and survival traits within age were positive (0.02 to 0.05) at the early life stage and negative (−0.06 to −0.22) at later growth phase, which indicated that selecting for growth traits may not cause a positive correlated response in survival traits. Our results also showed that the uniformity ratio and correlation coefficient of families at adjacent growth stage increasing with age, which suggested that selection applied at early stage may result in only poor response and selection after week 14 can increase selection accuracy and accelerate the breeding process.

Genome-wide association study of growth and reproductive traits based on low-coverage whole-genome sequencing in a Chubao black-head goat population

Growth traits and transmission of genetic potential of local rabbits were studied at Rabbitory unit of the University of Agriculture Peshawar. A total of 48 breeding rabbits (40 does and 8 bucks) were used in the study. General linear model (GLM) was used to study the effect of dam and sire on growth parameters. Average weaning weight and body weight gain was 0.449±0.04 and 0.615±0.15g, respectively. Mean heart girth and body length was found 15.33±2.21 and 15.74±2.09, respectively. Litter size was found 4.49±1.15. Dam and sire significantly (P &lt; 0.0001) affected litter size, weaning weight, body weight gain, heart girth and body length. Positive and significant correlation (0.93, P &lt; 0.0001) was found between body weight gain and heart girth followed by high positive correlation (0.90) between body weight gain and body length. Heritability estimate (h2) for weaning weight and body weight gain was 0.94 and 0.14, respectively, while (h2) for heart girth and body length was 0.15 and 0.08, respectively. It was concluded from the study that dam and sire had significant and linear affect on weaning weight, body weight gain and other morphometric traits. Weaning weight heritability estimates indicating it as a candidate trait for selection in local rabbits. Relationship between heart girth and body weight is much stronger and may be consider in selective breeding.

The growth traits help rural farmers who lack weighing equipment to anticipate the body weights of their animals for a variety of reasons, including feeding, medication, and breeding purposes. The study aims to predict body weights from the growth traits of Doper sheep. Data on growth traits such as body length, heart girth, sternum height, withers height, rump height, and body weight were collected for one day from 50 Dorper sheep aged 1 to 2 years. Pearson's correlation and simple linear regression analysis were used to achieve the study's objectives. Pearson’s correlation results in ewes indicated that body weights had a positive significant relationship with heart girth, wither height, and body length. Whereas in rams, body weights showed to be positively and statistically correlated to withers and sternum height. Simple linear regression demonstrated the highest coefficient with the lowest mean square error on heart girth in ewes and sternum and withers height in rams. Correlations suggest that increasing heart girth, withers height, and body length in ewes and withers and sternum height in rams might cause body weights to increase. The regression analysis in ewes revealed that heart girth contributes 27% of the variation in body weights, whereas sternum or withers height contributes 61% of the variation in rams. In conclusion, to improve body weights, ewes' heart girth, withers height, body length, and rams' withers and sternum heights and heart girth, may be selected.

The objective of this investigation was to estimate the (co)variance components and genetic parameters for pre-weaning growth traits in inter-cross sheep maintained at NTRS, ICAR-CSWRI, Garsa, India. Data records of 1891 lambs for birth weight (BW) and 1763 lambs for weaning weight (WW) descending from 183 rams and 667 dams, born between 2012 and 2023, were utilised in the study. The live weight was used for the calculation of pre-weaning average daily weight gain (PDWG), pre-weaning Kleiber ratio (PKR), pre-weaning growth efficiency (PGE) and pre-weaning relative growth rate (PGR). The fixed effects used in the model were birth year, genetic group, sex, type of birth, and parity of dam. Estimation of covariance components was carried out by fitting a series of animal models using the average information restricted maximum likelihood (AIREML) algorithm. The best-fitting model was determined after testing for improvement in log-likelihood values. The overall LSM ± SE for BW, WW, PADG, PKR, PGE, and PGR were 3.29 ± 0.04 kg, 14.83 ± 0.22 kg, 127.87 ± 2.46 g, 16.78 ± 0.13, 357.53 ± 7.13, and 1.66 ± 0.02, respectively. Analysis revealed that pre-weaning traits were significantly (p < 0.05) affected by year of birth, parity of dam, type of birth and sex of the lamb. Direct heritability estimates were 0.11 ± 0.04, 0.16 ± 0.04, 0.16 ± 0.04, 0.15 ± 0.06, 0.18 ± 0.06 and 0.17 ± 0.06 for BW, WW, PADG, PKR, PGE, and PGR, respectively. The corresponding maternal heritability estimates for BW, PKR, PGE, and PGR traits were 0.19 ± 0.03, 0.11 ± 0.04, 0.13 ± 0.04, and 0.12 ± 0.04, respectively. For WW and ADWG, only direct effects were significant. The correlations of WW with efficiency-related traits and among the other traits were quite high and positive. Significant impact of maternal care for early growth traits in this breed indicates the importance of considering both direct and maternal effects for genetic evaluation. The moderate estimate of heritability for WW with high and positive genetic correlations with other traits, makes this trait a candidate for selection in the present flock. We therefore recommend the use of WW as a single trait selection criterion for the overall improvement of the growth traits in the sheep flock.

The aim of the current study was to estimate the genetic parameters for growth and hypoxic tolerance traits in Pacific white shrimp Litopenaeus vannamei at 8 and 13 weeks of ages. Forty full-sib families (including 28 half-sib families) of L. vannamei, which were produced by 26 sires and 40 dams, were obtained by artificial insemination. There were a total of 3,200 tagged shrimps representing 40 full-sib families evaluated for growth and hypoxic tolerance traits in this study (1,600 records were collected at weeks 8 and 13, respectively). The heritability estimates for growth traits were low to medium (0.11–0.23), and the heritability of hypoxic tolerance traits estimated on the observed scales was also low to medium (0.07–0.15), which suggested that selection for increasing growth and hypoxic tolerance traits was feasible. The genetic correlations between growth traits (including carapace length, abdominal segment length, body length, and body weight) within age were generally high, ranging from 0.84 ± 0.06 to 0.95 ± 0.02 (P &amp;lt; 0.05). A significant correlation between growth traits showed that any growth traits can be replaced by other growth traits for indirect selection. The genetic correlation between growth traits and hypoxic tolerance traits within age was low but positive (0.24–0.29), which indicated that selecting for growth traits will cause a positive correlated response in hypoxic tolerance traits. Our results also showed that there was a relatively low genetic correlation between growth traits at different ages (0.18–0.25), which suggested that selection for growth traits in L. vannamei at an early age may not be optimal and should be undertaken at later stages of growth.

Abstract----the objective of this research was to estimate genetic and phenotypic parameters for growth and milk production traits of Abergelle goats in community-based breeding program (CBBP) scale up village. The data used in the study was six years (2018-2023) data from the established village of goat community based breeding program area. The traits studied were, birth weight (BWT), weight at three months (TMWT), weight at six months (SMWT), weight at nine months (NMWT), yearling weight (YWT), direct heritability for growth and milk traits was computed by using WOMBAT software. Univariate mixed animal model was applied to estimate genetic parameters. Bivariate analysis was utilized to estimate correlations between traits. The overall least square mean of body weights ± standard errors (LSM±SE) for BWT, TMWT, SMWT, NMWT, and YWT were 2.3±0.04, 7.5±0.03, 8.8±0.040, 12.1±0.067, and 15.3±0.092 kg, respectively. The direct heritability estimates for BWT, TMWT, SMWT, NMWT, and YWT were 0.34±0.070, 0.45±0.062, 0.40±0.040, 0.42±0.07and 0.41±0.14, respectively. Phenotypic correlation of BWT with TMWT, SMWT, NMWT and YWT was low but that of TMWT-SMWT, SMWT-NMWT and NMWT-YWT was high and positive. The genetic correlations of birth weight with the studied growth traits were moderate but higher correlations were found among the other growth traits (SMWT, NMWT, and YWT), indicating as one of these traits increases; the others tend to increase as well. Therefore, birth weight as growth trait had no strong relation with later stages of growth traits in this study for Abergelle goat in scale up community based breeding programs.

Precise estimates of genetic parameters are required for genetic evaluation systems. This study combined data from 7 research resource flocks across Australia to estimate variance components and genetic parameters for production traits in the Australian Merino sheep. The flocks were maintained for several generations and represented contemporary Australian Merino fine, medium, and broad wool bloodlines over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, and 50 000 records for reproduction and growth traits with over 2700 sires and 25 000 dams. A linear mixed animal model was used to analyse 6 wool traits comprising clean fleece weight (CFW), greasy fleece weight (GFW), fibre diameter (FD), yield (YLD), coefficient of variation of fibre diameter (CVFD), and standard deviation of fibre diameter (SDFD), 4 growth traits comprising birth weight (BWT), weaning weight (WWT), yearling weight (YWT), and hogget weight (HWT), and 4 reproduction traits comprising fertility (FER), litter size (LS), lambs born per ewe joined (LB/EJ), and lambs weaned per ewe joined (LW/EJ). The range of direct heritability estimates for the wool traits was 0.42 ± 0.01 for CFW to 0.68 ± 0.01 for FD. For growth traits the range was 0.18 ± 0.01 for BWT to 0.38 ± 0.01 for HWT, and for reproduction traits 0.045 ± 0.01 for FER to 0.074 ± 0.01 for LS. Significant maternal effects were found for wool and growth, but not reproduction traits. There was significant covariance between direct and maternal genetic effects for all wool and growth traits except for YWT. The correlations between direct and maternal effects ranged from –0.60 ± 0.02 for GFW to –0.21 ± 0.10 for SDFD in the wool traits and from –0.21 ± 0.03 for WWT to 0.25 ± 0.08 for HWT in the growth traits. Litter effects were significant for all wool and growth traits and only for LS in reproduction traits. The mating sire was fitted in the models for reproduction traits and this variance component accounted for 21, 17, and 8% of the total phenotypic variation for FER, LB/EJ, and LW/EJ, respectively. The implications of additional significant variance components for the estimation of heritability are discussed.

A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep

BackgroundThe largemouth bass (Micropterus salmoides), an economically important freshwater fish species widely farmed in China, is traditionally cultured using a diet of forage fish. However, given the global decline in forage fish fisheries and increasing rates of waterbody pollution and disease outbreaks during traditional culturing, there is a growing trend of replacing forage fish with formulated feed in the largemouth bass breeding industry. The specific molecular mechanisms associated with such dietary transition in this fish are, nevertheless, poorly understood.MethodsTo identify single nucleotide polymorphisms (SNPs) related to food habit domestication traits and growth traits in largemouth bass fry, we initially genotyped fry using eight candidate SNPs based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, with genetic parameters being determined using Popgen32 and Cervus 3.0. Subsequently, we assessed the associations between food habit domestication traits of largemouth bass fry and these SNPs using the Chi-square test or Fisher’s exact test. Furthermore, we used a general linear model to assess the relationships between the growth traits of largemouth bass fry and these SNPs. The Pearson correlation coefficient between growth traits and the SNPs was also determined using bivariate correlation analysis in IBM SPSS Statistics 22. Finally, the phenotypic variation explained (PVE) by the SNPs was calculated by regression analysis in Microsoft Excel.ResultsThe genotyping results obtained based on PCR-RFLP analysis were consistent with those of direct sequencing. Five SNPs (SNP01, SNP02, SNP04, SNP05, and SNP06) were found to be significantly correlated with the food habit domestication traits of fry (P < 0.05); SNP01 (P = 0.0011) and SNP04 (P = 0.0055) particularly, had showed highly significant associations. With respect to growth traits, we detected significant correlations with the two SNPs (SNP01 and SNP07) (P < 0.05), with SNP01 being significantly correlated with body length, and height (P < 0.05), and SNP07 being significantly correlated with body height only (P < 0.05).ConclusionsOur findings indicated that the PCR-RFLP can be used as a low-cost genotyping method to identify SNPs related to food habit domestication and growth traits in largemouth bass, and that these trait-related SNPs might provide a molecular basis for the future breeding of new varieties of largemouth bass.

The Suffolk is a meat-type sheep that is the predominant terminal-sire breed in the U.S. Known for its rapid growth, high carcass yield, and efficient feed conversion, Suffolk rams are crucial in commercial crossbreeding systems. Despite its importance, the parameters used by the National Sheep Improvement Program (NSIP) in its genetic evaluation have not been updated in over two decades. Therefore, we re-estimated genetic and phenotypic parameters and calculated theoretical accuracies and genetic trends for various growth, body composition, and reproductive traits in U.S. Suffolk sheep. The traits evaluated were birth weight (BWT), weaning weight (WWT), post-weaning weight (PWWT), post-weaning eye muscle depth (EMD), post-weaning fat depth (CFAT), and number of lambs born (NLB) and weaned (NLW) per ewe lambing. The dataset consisted of a pedigree comprising 70,271 individuals and up to 48,000 phenotypic records per trait across more than 100 flocks. Variance components were estimated using the Restricted Maximum Likelihood method and animal models with maternal and permanent environmental effects fitted when appropriate. Records were pre-adjusted for age at recording, birth type, rearing type, and dam age as relevant. For lamb traits, contemporary group (CG; concatenation of flock, birth year, management group, sex, lambing interval, and recording date, except for BWT) was the only fixed effect included in the models. For reproductive traits, CG combined flock and lambing year; ewe age was added as a categorical fixed effect. Heritability estimates (±SE) ranged from 0.04 ± 0.008 for NLW to 0.24 ± 0.025 for CFAT. Maternal heritabilities ranged from 0.02 ± 0.01 for PWWT to 0.16 ± 0.011 for BWT. Genetic correlations among growth traits ranged from 0.47 ± 0.07 to 0.67 ± 0.04, and genetic correlations between PWWT and body composition traits were positive (0.30 ± 0.09 with EMD and 0.55 ± 0.08 with CFAT). A strong genetic correlation (0.81 ± 0.03) was observed between NLB and NLW. Theoretical accuracy was highest for proven animals with progeny records. Genetic trends showed progress in growth and muscling traits but declining maternal breeding values for growth traits. Several updated genetic parameters diverged from legacy NSIP estimates, likely due to shifts in management, and trait definitions. These results emphasize the need for regular re-estimation of genetic parameters to ensure accurate genetic evaluations and promote balanced genetic progress across traits.