scholarly journals Genetic factors of functional traits

2021 ◽  
Vol 29 (4) ◽  
pp. 207-220
Author(s):  
Mª Luz García ◽  
Melanie Gunia ◽  
Mª José Argente
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Functional Traits ◽  
Genetic Correlations ◽  
Antibiotic Use ◽  
Production Traits ◽  
Immunity Genes ◽  
First Results ◽  
Size Variability

Selection of functional traits is a challenge for researchers, but an increasingly necessary objective due to the growing concern regarding animal welfare and overcoming the problems of reducing antibiotic use in rabbit production without undermining the animals’ productivity. The aim of this review is to discuss the genetic control of resistance to diseases, longevity and variability of birth weight within a litter, or litter size variability at birth within doe, describing the selection programmes and the first results from a multi-omics analysis of resistance/susceptibility to diseases. The heritability is around 0.13 for longevity, 0.01 for uniformity in birth weight, 0.09 for litter size variability and around 0.11 for disease resistance. Genetic correlations between functional traits and production traits are mostly no different from zero, or are moderately favourable in some cases. Six selection programmes developed in three countries are reviewed. Line foundation with high pressure for selection or divergent selection experiments are different methodologies used, and favourable responses to selection have been achieved. Genomics studies have revealed associations in regions related to immune system functionality and stress in lines selected for litter size variability. Knowledge of the role of gut microbiota in the rabbit’s immune response is very limited. A multi-omics approach can help determine the microbial mechanisms in regulation immunity genes of the host.

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 The Share of Variance Components and Correlations Between Sow Production Traits in Different Treatments of the Litter Size (The Repeatability and Multi-Trait Models)

2018 ◽  
Vol 67 (3-4) ◽  
pp. 207-214
Author(s):  
Dragan Radojković ◽  
Radomir Savić ◽  
Mladen Popovac ◽  
Čedomir Radović ◽  
Marija Gogić
Keyword(s):  
Litter Size ◽  
Variance Components ◽  
Genetic Correlations ◽  
Production Traits ◽  
Dispersion Parameters ◽  
Total Variability ◽  
Breeding Selection ◽  
The Common ◽  
Trait Model ◽  
The Republic

Summary The share of variance components and correlations between the most important sow production traits (namely duration of fattening - DF, backfat thickness - BF and number of liveborn piglets - NBA) included in the pig breeding selection programme of the Republic of Serbia were estimated in this paper. The litter size at repeated farrowings (NBA1,..., NBA6) was treated as a separate trait (the multi-trait model), whereas the litter size at birth was treated as a trait repeated a number of times (the repeatability model)). The estimation of dispersion parameters was performed using the Restricted Maximum Likelihood (REML) method. The heritability of DF accounted for 23.5%, i.e. 23.3% depending on the model used, whereas BF accounted for 40.4% in both cases. The heritability of the litter size in consecutive farrowings (the multi-trait model) were in intervals ranging between 0.104 (NBA1) and 0.136 (NBA5). The heritability of NBA in the repeatability treatment accounted for 0.106, whereas the common litter environment and the permanent sow influence contributed to the total variability with 1.1% and 5.6%, respectively. Genetic correlations between the traits examined were not determined, with the exception of consecutive farrowings in the multi-trait treatment of the litter size. The genetic correlations recorded in this case proved positive and complete, with the exception of the correlation between the first and subsequent farrowings (farrowings 3 to 6) and the correlation between the second and the last farrowings (farrowings 5 and 6), which proved very strong.

Litter size at lambing influences genetic evaluation of maternal rearing ability

2018 ◽  
Vol 58 (5) ◽  
pp. 791
Author(s):  
Kim L. Bunter ◽  
Andrew A. Swan ◽  
Daniel J. Brown ◽  
Forbes D. Brien ◽  
Jennifer Smith
Keyword(s):  
Litter Size ◽  
Genetic Correlations ◽  
Genetic Evaluation ◽  
Size Class ◽  
Industry Data ◽  
Common Mean ◽  
Mean And Variance ◽  
Highly Correlated ◽  
Change In Mean

The genetic parameters for maternal rearing-ability of ewes were investigated by ignoring or defining the rearing ability trait separately by litter-size class (singles versus multiples) using multi-generational data from three, fully pedigreed Merino flocks differing in prolificacy, production level and environment. Genetic correlations (ra) between litter size (LSIZE) and the percentage of lambs surviving (PLSURV) were more negative with an increasing mean flock litter size (ra: –0.21 ± 0.17 to –0.73 ± 0.08), while the corresponding range in phenotypic correlations (rp) was substantially lower (rp: –0.15 ± 0.01 to –0.33 ± 0.01). Rearing-ability traits defined separately by litter-size class were highly correlated (ra: 0.49 ± 0.19 to 0.64 ± 0.38), but not genetically identical traits in the most prolific flock. Defining rearing-ability traits separately by litter-size class reduced the antagonistic genetic correlations between LSIZE and PLSURV to between –0.39 ± 0.14 and 0.14 ± 0.28, through accommodating the change in mean and variance of PLSURV with LSIZE. Similarly, linear transformation (TSURV) of PLSURV within each litter size to a common mean and variance reduced the antagonistic trend in genetic correlations between LSIZE and TSURV to range between –0.05 ± 0.17 and –0.43 ± 0.13. Since genetic correlations are low to moderate between TSURV and LSIZE, it is possible to select for improvements in both the number of lambs born and lamb survival simultaneously. Defining rearing-ability traits separately by litter-size class and the role of transformation will be investigated further for improving the accuracy of genetic evaluation for rearing ability across a range of flocks, breeds and environmental conditions using more extensive industry data.

scholarly journals Role of Sex Chromatin on performance in the Arabi sheep

2017 ◽  
Vol 41 (1) ◽  
pp. 145-150
Author(s):  
Salim Omar Raoof
Keyword(s):  
Birth Weight ◽  
Milk Production ◽  
Fertility Rate ◽  
Lactation Period ◽  
Production Traits ◽  
Sex Chromatin ◽  
Total Milk ◽  
Daily Milk Production ◽  
Daily Milk

     This study was conducted on 122 Arabi sheep belonged to private flock in Erbil plain Kurdistan region- Iraq, from July/ 2014 to August/ 2015 for studying the role of sex chromatin on daily milk production, total milk production, lactation period, fertility rate, prolificacy, birth weight and fertilizes estrous sequences. The repeatability for the studied traits were estimated. The ratio of sex chromatin shapes drum stick, sessile nodule, tear drop and small club were 23.37%, 60.22%, 8.54% and 7.87% respectively.The overall means of daily milk production, total milk production, lactation period, birth weight, fertilize estrous sequences, fertility rate, and Prolificacy were 814.65 g 81.49 kg 103.53 day, 78.10%, 1.60, 3.84 kg and 1.50 respectively. Sex chromatin shapes had significant (P<0.05) effect on all traits studied. The results revealed that the estimation of the Repeatability coefficient for daily milk production was 0.42. It was concluded from this study that production traits (milk production and birth weight) and reproduction (fertility rate, prolificacy and fertilize estrous sequences) performance of Arabi sheep were significantly affected by the shapes and percentage of sex chromatin distribution and measurements. The sex chromatin shapes could be used as a tool for early selection of the elite individuals.

REML estimates of variance and covariance components for production traits in Australian Merino sheep, using an animal model. 1. Body weight from birth to 22 months

1996 ◽  
Vol 47 (8) ◽  
pp. 1235 ◽  
Author(s):  
Torshizi R Vaez ◽  
FW Nicolas ◽  
HW Raadsma
Keyword(s):  
Animal Model ◽  
Body Weight ◽  
Birth Weight ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Production Traits ◽  
Weaning Weight ◽  
Merino Sheep ◽  
Additive Genetic Effects ◽  
Australian Merino

Variance components for direct additive genetic, maternal additive genetic, and maternal environmental effects, and the covariance between direct and maternal additive genetic effects, were estimated by restricted maximum likelihood (REML) procedures, using an animal model, for body weight between birth and 22 months of age in Australian Merino sheep. Direct heritability was estimated to be 0.30 for birth weight, 0.28 for weaning weight, 0.24 for body weight at 10 months, 0.34 for body weight at 16 months, and 0.34 for body weight at 22 months. Maternal heritability estimates were 0.29, 0.41, 0.14, 0.07, and 0.07 for the same performances, respectively. Our results suggested that for birth weight and weaning weight, maternal additive genetic effects and the covariance between direct and maternal additive genetic effects were important. Following weaning, maternal additive genetic effects were the only significant maternal effects. Genetic correlations between direct and maternal additive effects were -0.43, -0.59, and -0.29 for birth weight, weaning weight, and body weight at 10 months, respectively. Direct and maternal additive genetic correlations between birth weight and body weight performances at later ages were positive and moderate, ranging from 0.17 to 0.52 and from 0.06 to 0.65, respectively, whereas they were positive and high between weaning weight and later weights, ranging from 0.59 to 0.77 and from 0.61 to 0.85, respectively. A carry-over of maternal influence after weaning was shown. Early (indirect) selection for body weight at weaning or 10 months will achieve a substantial proportion (between 53 and 81%) of direct response for performance at later ages (16 and 22 months).

Direct genetic and maternal effects affecting litter size, birth weight and pre-weaning losses in Creole goats of Guadeloupe

2003 ◽  
Vol 77 (3) ◽  
pp. 363-369 ◽  
Author(s):  
A. Menéndez-Buxadera ◽  
G. Alexandre ◽  
N. Mandonnet ◽  
M. Navès ◽  
G. Aumont
Keyword(s):  
Animal Model ◽  
Birth Weight ◽  
Genetic Variability ◽  
Litter Size ◽  
Direct Effect ◽  
Maternal Effects ◽  
Genetic Correlations ◽  
The Individual ◽  
Second Procedure

AbstractThe litter size (LS), or its equivalent the number of kids born in the litter (NB), of Creole goats in Guadeloupe was studied by two procedures. The first approach considered LS as a single trait and as a characteristic of the mother of the litter, and was studied by an univariate animal model (UAM). The second procedure treated NB, the individual birth weight (BW) and loss of kids (LK) as traits belonging to the animals born in the litter and their dam, in a multitrait animal model (MAM). The heritability for genetic direct effect (h2a) for LS estimated by UAM (0·14) was 40% lower than the corresponding value for NB estimated by MAM. The most appropriate of the 6 MAMs tested estimated heritabilities (h2a) of 0·24, 0·22 and 0·17 for NB, BW and LK, respectively, while maternal effects (h2m) were 0·20, 0·24 and 0·09 for the same characters. The genetic correlations between direct and maternal effects (ram) were negative –0·611 and –0·725 for NB and LK, respectively, and not significantly different from zero for BW. This study explored the possibility of using the information on NB, BW and LK recorded in each animal born in the litter in order to analyse the genetic variability of these traits.

scholarly journals  Impact of economic parameters on economic values in dairy sheep

2013 ◽  
Vol 58 (No. 1) ◽  
pp. 21-30 ◽  
Author(s):  
Z. Krupová ◽  
E. Krupa ◽  
M. Wolfová
Keyword(s):  
Milk Production ◽  
Litter Size ◽  
Functional Traits ◽  
Milk Yield ◽  
Growth Traits ◽  
Economic Value ◽  
Production Traits ◽  
Economic Values ◽  
Economic Parameters ◽  
The Impact

The impact of variation in economic conditions on the economic values of fourteen production and functional traits was examined for the Improved Valachian breed using a bio-economic model implemented in the ECOWEIGHT software. The following economic parameters were investigated: market prices of lambs, milk, and cheese (variation &plusmn; 40%), costs for roughage, concentrates, and total feeding rations , costs for labour and veterinary care, fixed costs (variation &plusmn; 20% for all costs), and discount rate of revenues and costs (0 and 3%). Results of the analyses were presented in detail for the marginal and relative economic values of the four most important traits: milk yield in the 150-day milking period, conception rate of ewes, litter size per lambed ewe, and productive lifetime of ewes. Furthermore, cumulative relative economic values of the four trait complexes &ndash; milk production, growth, functional, and wool traits &ndash; were presented. Prices for sheep products were found to be the most important factor for both the marginal and the relative economic values of the evaluated traits. The four traits with the highest relative economic values in the base calculation stayed the most important for all investigated economic parameters ranges. The relative economic values of the remaining 10 traits did not exceed 6.1%. The relative economic values of milk yield and litter size were the most sensitive to the variation in economic circumstances. For the investigated range of economic parameters, the relative economic value for the complex of milk production traits ranged 30.6&ndash;48.1%, for growth traits 6.3&ndash;9.4%, and that for functional traits 45.4&ndash;59.7%. The relative economic value for the wool trait did not exceed 0.3%.

scholarly journals Genetic evaluation of production potential of Black Bengal goat using frozen semen under community based rearing system

2016 ◽  
Vol 45 (2) ◽  
pp. 52-59 ◽  
Author(s):  
MY Ali ◽  
SS Husain ◽  
SA Bhuiyan ◽  
MR Islam ◽  
MA Haque
Keyword(s):  
Birth Weight ◽  
Litter Size ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Production Potential ◽  
Community Based ◽  
Frozen Semen ◽  
Body Weights ◽  
Daily Milk Yield ◽  
Black Bengal Goat

The objective of this study was to investigate production potential of Black Bengal goat using frozen semen under community based-rearing system. Forty Black Bengal does were distributed to the goat keepers and inseminated with frozen semen of selected Black Bengal bucks. Statistical analyses of all parameters were done using SAS. Genetic parameters were also measured using VCE software. Means along with standard errors for productive performance were 0.96±0.01, 4.25±0.06, 7.04±0.12 kg, 36.51±0.64, 31.29±0.98 g/d, and 247.80±3.13 ml/d, respectively for birth weight, body weight at 3- and 6-month, average daily gain at 3- and 6-month and daily milk yield. Reproductive performances were 1.81±0.107, 1.44±0.097, 145.33±0.649 days, 200.60±2.83 days, 7.69±1.97 kg, 40%, 19.65%, respectively for litter size, service per  conception, gestation period, age and weight at first heat, conception rate and kid mortality. Effects of sex and litter size were significant (p<0.01) for birth and 3-month weight and season was significant (p<0.05) only for birth weight. Bucks showed significant effects (p<0.05) for birth and 3-month weight. Estimated heritability for birth, 3- and 6-month weight were 0.21±0.03, 0.36±0.07 and 0.12±0.05. Genetic correlations among body weights ranged from 0.35 to 0.65 and phenotypic correlations ranged from 0.44 to 0.52. Therefore, the AI program with frozen semen of Black Bengal buck would be beneficial to the farmers.Bang. J. Anim. Sci. 2016. 45 (2): 52-59

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.

Optimising sow and piglet welfare during farrowing and lactation

2021 ◽  
pp. 121-176
Author(s):  
Emma M. Baxter ◽  
◽  
Sandra Edwards ◽  
Keyword(s):  
Risk Factors ◽  
Birth Weight ◽  
Low Birth Weight ◽  
Litter Size ◽  
Environmental Enrichment ◽  
Production Traits ◽  
Health Issues ◽  
Environmental Interventions ◽  
Factors Associated ◽  
Continued Use

Optimising welfare in the farrowing and lactation environment involves resolving the concerns regarding continued use of close confinement systems, such as the farrowing crate for the sows and the lack of provision of environmental enrichment to provide for behavioural needs. For piglets the main welfare and health issues surround high levels of piglet mortality and the pre-disposing risk factors associated with them. Some of these risk factors, such as low birth weight, have been exacerbated by narrow breeding goals focussed on production traits such as increasing litter size. This chapter will concentrate on managerial and environmental interventions that attempt to reconcile the behavioural and physiological needs of both the sow and piglets to optimise their welfare whilst appreciating stockperson concerns with how best to implement them.

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