Usefulness of running animal models in absence of pedigrees: Estimation of genetic parameters for gastrointestinal parasite resistance traits in Djallonké sheep of Burkina Faso

2018 ◽  
Vol 160 ◽  
pp. 81-88 ◽  
Author(s):  
Isabel Álvarez ◽  
Amadou Traoré ◽  
Iván Fernández ◽  
Isabel Cervantes ◽  
Luis Varona ◽  
...  
Keyword(s):  
Animal Models ◽  
Burkina Faso ◽  
Genetic Parameters ◽  
Gastrointestinal Parasite ◽  
Parasite Resistance ◽  
Estimation Of Genetic Parameters ◽  
Resistance Traits

scholarly journals Comparison between methods for measuring fecal egg count and estimating genetic parameters for gastrointestinal parasite resistance traits in sheep

2021 ◽  
Author(s):  
M N Boareki ◽  
F S Schenkel ◽  
O Willoughby ◽  
A Suarez-Vega ◽  
D Kennedy ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Gastrointestinal Parasite ◽  
Parasite Resistance ◽  
Multiple Trait ◽  
Fecal Egg Count ◽  
Counting Methods ◽  
Mean And Variance ◽  
Resistance Traits

Abstract Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to evaluate the difference in means and variances between two fecal egg counting methods used in sheep, the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); to estimate variance components for the two FEC methods, treating them as two different traits; and to integrate FEC data from the two different methods and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. Fecal samples were collected from a commercial Rideau-Arcott sheep farm in Ontario. Fecal egg counting was performed using both Modified McMaster and the Triple Chamber McMaster methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA ©), body condition score (BCS), and body weight (WT). The two FEC methods were highly genetically (0.94) and phenotypically (0.88) correlated. However, the mean and variance between the two FEC methods were significantly different (P < 0.0001). Therefore, re-scaling is required prior to integrating data from the different methods. For the multiple trait analysis, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with re-standardized LTCM records converted to the same mean and variance of LMMR. Heritability estimates were 0.12 ± 0.04, 0.07 ± 0.05 , 0.17 ± 0.06, and 0.24 ± 0.07 for LFEC egg count, FAMACHA ©, BCS, and WT, respectively. The estimated genetic correlations between fecal egg count and the other parasite resistance traits were low and not significant (P>0.05) for FAMACHA © (r= 0.24 ± 0.32) and WT (r= 0.22 ± 0.19), and essentially zero for BCS (r= -0.03 ± 0.25), suggesting little to no benefit of using such traits as indicators for LFEC.

scholarly journals PSIII-8 Difference between two fecal egg count methods and estimation of genetic parameters for gastrointestinal parasite resistance traits in sheep

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 232-233
Author(s):  
Mohammed N Boareki ◽  
Olivia Willoughby ◽  
Delma Kennedy ◽  
Aroa Suarez-Vega ◽  
Larry Schaeffer ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Gastrointestinal Parasite ◽  
Parasite Resistance ◽  
Multiple Trait ◽  
Fecal Egg Count ◽  
Mean And Variance ◽  
The Difference ◽  
Resistance Traits

Abstract Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to: evaluate the difference between two FEC methods, the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); estimate the genetic and phenotypic correlations between records from two methods; and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. A total of 1,676 fecal samples were collected from a commercial sheep farm between 2012 and 2019. Fecal egg counting was performed using the Modified McMaster (n = 998) and the Triple Chamber McMaster (n = 678) methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA©), body condition score (BCS), and body weight (WT). The mean and variance between the two FEC methods were significantly different (P < 0.0001), but phenotypic and genetic correlations between them were high (0.88 and 0.94, respectively). Therefore, pre-adjustment is required prior to integrating data from the different methods. For multiple trait analysis with other parasite resistance traits, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with standardized LTCM records for mean and variance of LMMR. Heritability estimates were 0.12, 0.07, 0.17, and 0.24, for LFEC, FAMACHA©, BCS, and the WT, respectively. Estimated genetic correlations between fecal egg count and the other parasite resistance traits were low with FAMACHA© (0.24), BCS (-0.03), and WT (0.22), suggesting little to no benefit of using such traits as indicators for LFEC.

Estimation of genetic parameters for disease-resistance traits in Cynoglossus semilaevis (Günther, 1873)

2016 ◽  
Vol 32 (4) ◽  
pp. 643-651 ◽  
Author(s):  
F. Liu ◽  
Y. Z. Li ◽  
X. X. Wang ◽  
X. F. Liu ◽  
H. F. Xing ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Genetic Parameters ◽  
Cynoglossus Semilaevis ◽  
Estimation Of Genetic Parameters ◽  
Resistance Traits

PSVIII-8 Genetic parameters for parasite resistance in an endangered and heritage sheep breed from Florida

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 242-242
Author(s):  
Zaira M Estrada-Reyes ◽  
Jorge A Hidalgo Moreno ◽  
Brittany N Diehl ◽  
Ibukun M Ogunade ◽  
Andres A Pech-Cervantes ◽  
...  
Keyword(s):  
Body Condition ◽  
Genetic Parameters ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
The United States ◽  
Parasite Resistance ◽  
Southern Us ◽  
Condition Score ◽  
Native Sheep ◽  
Resistance Traits

Abstract The Florida Native Sheep is one of the oldest sheep breeds in the United States. This heritage breed from Florida, naturally adapted to humid and hot climate conditions, is one of the most parasite resistant breeds from the Southern US. However, only approximately 1,000 individuals remain alive in the world. Therefore, conservation efforts and breeding programs are critical for survival of this breed. The objective of this research was to estimate genetic parameters for parasite resistance and body condition score in Florida Native sheep. The pedigree file contained 695 animals born between 2018 and 2020 and included 279 individuals with genotypes (38,429 SNP after quality control). The dataset contained 365 animals with phenotypic records at 38 days post-infection (natural Haemonchus contortus infection) for fecal egg count (FEC), blood packed count volume (PCV), FAMACHA score (FAM), and body condition score (BCS). Genetic parameters were estimated using a multi-trait model with a Bayesian implementation in the GIBBS3F90 program. Heritabilities were 0.38 0.07, 0.47 0.05, 0.27 0.04, and 0.52 0.07 for FEC, PCV, FAM, and BCS. Genetic correlations among parasite resistance traits were high and favorable: -0.82 0.06 (FEC-PCV), 0.83 0.07 (FEC-FAM), and -0.94 0.03 (PCV-FAM). Genetic correlations among parasite resistance traits and BCS were -0.42 0.11 (FEC-BCS), 0.75 0.09 (PCV-BCS), and -0.82 0.05 (FAM-BCS). Genetic progress for parasite resistance is possible in Florida Native sheep. The FAMACHA score is a phenotypic parameter easy to record in sheep; therefore, genetic selection for this trait can be effective to improve the remaining traits.

scholarly journals Estimation of genetic parameters and trends for energy-corrected 305-d milk yield in Iranian Holsteins

2012 ◽  
Vol 55 (5) ◽  
pp. 420-426
Author(s):  
N. G. Hossein-Zadeh
Keyword(s):  
Animal Models ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Physiological Mechanism ◽  
Animal Breeding ◽  
Dairy Herds ◽  
Breeding Values ◽  
Estimation Of Genetic Parameters ◽  
Genetic Trends

Abstract. Calving records from the Animal Breeding Centre of Iran collected from January 1995 to December 2007 and comprising 217973 calving events of Holsteins from 704 dairy herds were analysed using univariate and bivariate linear animal models to estimate heritabilities and genetic correlations for energy-corrected 305-d milk yield (ECM) in the first three lactations of Holstein cows. Genetic trends were obtained by regressing yearly mean estimates of breeding values on calving year. Average ECM increased from parity 1 through parity 3. Estimates of heritabilities were from 0.14 to 0.21 for ECM and decreased over the parities. The greatest genetic correlations were between ECM2 and ECM3 (0.96), and the greatest phenotypic correlations were between ECM1 and ECM2 (0.57) and ECM2 and ECM3 (0.57). The high and positive genetic correlations between ECM traits at different lactations are evidence for common genetic and physiological mechanism controlling these traits. There were positive and increasing phenotypic and genetic trends for ECM over the years (P<0.001). Higher heritability of the ECM in the first parity along with the high genetic correlations between first-lactation ECM with these traits in other lactations shows that higher potential exists for selecting animals for ECM based on their first parity records.

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