Occurrence and identification of Emeria species in broiler rearing under traditional system

Shamim, Asim; Hassan, Murtaz Ul; Yousaf, Arfan; Iqbal, Muhammad Farooq; Zafar, Maryam; Siddique, Rao Muhammad; Abubakar, Muhammad

doi:10.1186/s40781-015-0074-0

Cited by 14 publications

(17 citation statements)

References 18 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, purebred birds in large commercial breeding companies are typically disease-free from salmonella, mycoplasma, leucosis, avian influenza and Newcastle disease [32]. However, these diseases remain chronic problems in many commercial poultry flocks [33–35]. The difference between the B and C environments may also be related to diet and litter management.…”

Section: Discussionmentioning

confidence: 99%

Use of genomic information to exploit genotype-by-environment interactions for body weight of broiler chicken in bio-secure and production environments

et al. 2019

View full text Add to dashboard Cite

Background The increase in accuracy of prediction by using genomic information has been well-documented. However, benefits of the use of genomic information and methodology for genetic evaluations are missing when genotype-by-environment interactions (G × E) exist between bio-secure breeding (B) environments and commercial production (C) environments. In this study, we explored (1) G × E interactions for broiler body weight (BW) at weeks 5 and 6, and (2) the benefits of using genomic information for prediction of BW traits when selection candidates were raised and tested in a B environment and close relatives were tested in a C environment. Methods A pedigree-based best linear unbiased prediction (BLUP) multivariate model was used to estimate variance components and predict breeding values (EBV) of BW traits at weeks 5 and 6 measured in B and C environments. A single-step genomic BLUP (ssGBLUP) model that combined pedigree and genomic information was used to predict EBV. Cross-validations were based on correlation, mean difference and regression slope statistics for EBV that were estimated from full and reduced datasets. These statistics are indicators of population accuracy, bias and dispersion of prediction for EBV of traits measured in B and C environments. Validation animals were genotyped and non-genotyped birds in the B environment only. Results Several indications of G × E interactions due to environmental differences were found for BW traits including significant re-ranking, heterogeneous variances and different heritabilities for BW measured in environments B and C. The genetic correlations between BW traits measured in environments B and C ranged from 0.48 to 0.54. The use of combined pedigree and genomic information increased population accuracy of EBV, and reduced bias of EBV prediction for genotyped birds compared to the use of pedigree information only. A slight increase in accuracy of EBV was also observed for non-genotyped birds, but the bias of EBV prediction increased for non-genotyped birds. Conclusions The G × E interaction was strong for BW traits of broilers measured in environments B and C. The use of combined pedigree and genomic information increased population accuracy of EBV substantially for genotyped birds in the B environment compared to the use of pedigree information only.

show abstract

Section: Discussionmentioning

confidence: 99%

Use of genomic information to exploit genotype-by-environment interactions for body weight of broiler chicken in bio-secure and production environments

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Other possible explanation to the change in heritability for BW at weeks 2–3 could be diseases. Birds around this age are prone to coccidiosis and other diseases of the digestive tract (Shamim et al, ) that affect BW of broilers. Respiratory diseases caused by infectious bronchitis virus, avian metapneumovirus and mycoplasma species may also affect BW of broilers at this age, when the level of maternal antibodies declines substantially and birds start to croak (De Boeck, Kalmar, Dumont, & Vanrompay, ).…”

Section: Discussionmentioning

confidence: 99%

Genetic analysis on body weight at different ages in broiler chicken raised in commercial environment

Chu

Madsen

Norberg

et al. 2019

J Animal Breeding Genetics

View full text Add to dashboard Cite

A multivariate model was developed and used to estimate genetic parameters of body weight (BW) at 1–6 weeks of age of broilers raised in a commercial environment. The development of model was based on the predictive ability of breeding values evaluated from a cross‐validation procedure that relied on half‐sib correlation. The multivariate model accounted for heterogeneous variances between sexes through standardization applied to male and female BWs differently. It was found that the direct additive genetic, permanent environmental maternal and residual variances for BW increased drastically as broilers aged. The drastic increase in variances over weeks of age was mainly due to scaling effects. The ratio of the permanent environmental maternal variance to phenotypic variance decreased gradually with increasing age. Heritability of BW traits ranged from 0.28 to 0.33 at different weeks of age. The direct genetic effects on consecutive weekly BWs had high genetic correlations (0.85–0.99), but the genetic correlations between early and late BWs were low (0.32–0.57). The difference in variance components between sexes increased with increasing age. In conclusion, the permanent environmental maternal effect on broiler chicken BW decreased with increasing age from weeks 1 to 6. Potential bias of the model that considered identical variances for sexes could be reduced when heterogeneous variances between sexes are accounted for in the model.

show abstract

“…With highly bio-secure procedures, purebred birds in the Aviagen commercial breeding company are completely disease-free from Salmonellae, Mycoplasma, Leucosis, Avian Influenza and Newcastle disease . Meanwhile, these diseases remain chronic problems in many commercial poultry flocks EFSA, 2017;Shamim et al, 2015). shows that the incidence of food-pad dermatitis in birds of C environment was up to 3.5 times more than birds in B environment.…”

Section: Breeding Environments Versus Production Environmentsmentioning

confidence: 99%

“…For example, purebred birds in large commercial breeding companies are typically disease-free from Salmonellae, Mycoplasma, Leucosis, Avian Influenza and Newcastle disease . However, these diseases remains chronic problems in many commercial poultry flocks (De EFSA, 2017;Shamim et al, 2015). The difference between B and C may be also related to diet and litter management.…”

Section: Genotype-by-environment Interactionmentioning

confidence: 99%

“…Other possible explanation to the change of heritability for BW at week 2-3 could be diseases. Birds around this age are prone to coccidiosis and other diseases of the digestive tract(Shamim et al, 2015) that affect BW of broilers. Respiratory diseases caused by infectious bronchitis virus, avian metapneumovirus and mycoplasma species may also affect BW of broilers at this age, when level of maternal antibodies declines substantially and birds start to croak (De…”

mentioning

confidence: 99%

See 1 more Smart Citation

Genotype by environment interactions in poultry breeding programs

Tuan

View full text Add to dashboard Cite

Environmental differences between the breeding (B) and commercial production (C) environments may lead to genotype-by-environment interactions (GxE) i.e. re-ranking of breeding values of animals in the two environments. A substantial re-ranking implies genetic progress achieved in breeding programs is not realized in performance of production animals. The issues of GxE are not new and several solutions exist, however, there has not been much focus on solutions for breeding programs for poultry. This PhD-project investigated GxE interactions in breeding programs for poultry and solutions to improve genetic progress in these breeding programs. A strong GxE interaction for body weight (BW) traits was found in broilers that were raised in B and C environments. Indications of GxE were significant re-ranking of breeding values, heterogeneous variances and different heritability for BW under B and C conditions. The genetic correlations between BW traits measured in B and C environments were in the range 0.48-0.54. Genetic variances of C traits were more than 2 times higher than those of B traits. Heritability of C traits (0.31-0.37) were higher than those of B traits (0.27-0.30). In this thesis, several approaches to improve genetic gains of the poultry breeding programs in the presence of GxE have been investigated: phenotyping strategies, optimal modelling of traits, use of group records, and the use of genomic information. Different phenotyping strategies were compared in a breeding program for broilers that used genomic selection. It was found that when the genetic correlations between traits measured in B and C were 0.5 and 0.7, allocation of 70% and 30% hatched birds to B and C environments, respectively, for phenotype testing led to the highest genetic gains among the compared phenotyping strategies. When the genetic correlation was 0.9, moving birds to C did not improve genetic gains of the breeding scheme due to reduced selection intensity. Increasing proportion of birds moved to C (from 15 to 45%) could reduce rate of inbreeding of the breeding program. Optimal modelling of traits was explored in a genetic analysis that was carried out for BW in broilers at different ages raised in a commercial environment. A statistical model was developed with the aim to increase predictive ability of the model for the traits affected by maternal effects. A criterion for the development of the statistical model was based on correlation between EBVs and corrected phenotypes of half-sib individuals. The statistical model also accounted for heterogeneous variances between sexes. In breeding programs for village chicken, where strong GxE interactions are expected, the use of group records was a good option to increase genetic gain of the breeding programs. The use of group records from villages significantly improved genetic gains compared to the scheme without birds tested in the village although group records led to a slightly lower genetic gain compared to individual records. In addition, the use of genomic information was ex...

show abstract

Occurrence and identification of Emeria species in broiler rearing under traditional system

Cited by 14 publications

References 18 publications

Use of genomic information to exploit genotype-by-environment interactions for body weight of broiler chicken in bio-secure and production environments

Use of genomic information to exploit genotype-by-environment interactions for body weight of broiler chicken in bio-secure and production environments

Genetic analysis on body weight at different ages in broiler chicken raised in commercial environment

Genotype by environment interactions in poultry breeding programs

Contact Info

Product

Resources

About