Pedigree analysis of Santa Inês sheep and inbreeding effects on performance traits

Barbosa, Artur Felipe Santos; Romano, Gabrieli De Souza; Velarde, Jonatan Mikhail Del Solar; Ferraz, José Bento Sterman; Pedrosa, Victor Breno; Pinto, Luís Fernando Batista

doi:10.22319/rmcp.v11i2.4899

Cited by 5 publications

(9 citation statements)

References 19 publications

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“…In terms of maximum, full complete and equivalent complete generations, the structure of the NSIP Katahdin pedigree was comparable to that of other breeds. The maximum number of generations (9.3) was within the range of 8.0 to 13.0 generations estimated for Mexican populations of Suffolk, Rambouillet, Barbados Blackbelly, Katahdin and Indian Marwari sheep (Domínguez‐Viveros, 2020; Vyas et al., 2022). For complete generations, the NSIP Katahdin tended to be lower (1.8) than the estimates in most other breeds, which ranged from 2.3 to 6.0, although comparable to the 0.9 to 2.0 complete generations observed in Brazilian Morada Nova hair sheep (Domínguez‐Viveros, 2020; Matos & Lôbo, 2021; McManus et al., 2019; Vatankhah et al., 2019; Vyas et al., 2022).…”

Section: Discussionsupporting

confidence: 59%

“…The maximum number of generations (9.3) was within the range of 8.0 to 13.0 generations estimated for Mexican populations of Suffolk, Rambouillet, Barbados Blackbelly, Katahdin and Indian Marwari sheep (Domínguez‐Viveros, 2020; Vyas et al., 2022). For complete generations, the NSIP Katahdin tended to be lower (1.8) than the estimates in most other breeds, which ranged from 2.3 to 6.0, although comparable to the 0.9 to 2.0 complete generations observed in Brazilian Morada Nova hair sheep (Domínguez‐Viveros, 2020; Matos & Lôbo, 2021; McManus et al., 2019; Vatankhah et al., 2019; Vyas et al., 2022). Lastly, the equivalent complete generations in the NSIP Katahdin (3.7) were most similar to Iranian Lori‐Bakhtiari sheep (3.8), but tended to be lower than in most other breeds with generations from 5.3 to 8.0 (Domínguez‐Viveros, 2020; Matos & Lôbo, 2021; McManus et al., 2019; Vatankhah et al., 2019; Vyas et al., 2022).…”

Section: Discussionsupporting

confidence: 59%

“…For complete generations, the NSIP Katahdin tended to be lower (1.8) than the estimates in most other breeds, which ranged from 2.3 to 6.0, although comparable to the 0.9 to 2.0 complete generations observed in Brazilian Morada Nova hair sheep (Domínguez‐Viveros, 2020; Matos & Lôbo, 2021; McManus et al., 2019; Vatankhah et al., 2019; Vyas et al., 2022). Lastly, the equivalent complete generations in the NSIP Katahdin (3.7) were most similar to Iranian Lori‐Bakhtiari sheep (3.8), but tended to be lower than in most other breeds with generations from 5.3 to 8.0 (Domínguez‐Viveros, 2020; Matos & Lôbo, 2021; McManus et al., 2019; Vatankhah et al., 2019; Vyas et al., 2022). While pedigree completeness may not be directly comparable across breeds due to the differences in age, popularity and distribution, the NSIP Katahdin pedigree is of suitable quality for diversity estimates.…”

Section: Discussionmentioning

confidence: 55%

“…When using the rate of inbreeding per generation, Canadian populations of Suffolk and Polypay had N e estimates of 99 and 55, respectively (Stachowicz et al., 2018). Mexican populations of Suffolk, Rambouillet, Barbados Blackbelly and Katahdin had ‘realized’ N e estimates of 34.7, 53.2, 36.8 and 73.5, respectively (Domínguez‐Viveros, 2020). Additionally, using the Suffolk pedigree from NSIP, N e estimates ranged from 27.5 to 182.9 based on the same methods utilized in this study (Wilson et al., 2022).…”

Section: Discussionmentioning

confidence: 99%

“…The generation interval for US Suffolk was estimated to be 2.92 years (Wilson et al., 2022). Mexican populations of Suffolk, Rambouillet, Barbados Blackbelly and Katahdin had estimates of 3.71, 3.91, 3.09, and 3.38 years, respectively (Domínguez‐Viveros, 2020). The generation intervals of Brazilian populations of Morada Nova were estimated to be between 3.49 and 4.69 years (Matos & Lôbo, 2021; McManus et al., 2019).…”

Section: Discussionmentioning

confidence: 99%

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Pedigree diversity and implications for genetic selection of Katahdin sheep

Nilson,

Burke,

Murdoch

et al. 2023

J Animal Breeding Genetics

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The Katahdin hair breed gained popularity in the United States as low input and prolific, with a propensity to exhibit parasite resistance. With the introduction of genomically enhanced estimated breeding values (GEBV) to the Katahdin genetic evaluation, defining the diversity present in the breed is pertinent. Utilizing pedigree records (n = 92,030) from 1984 to 2019 from the National Sheep Improvement Program, our objectives were to (i) estimate the completeness and quality of the pedigree, (ii) calculate diversity statistics for the whole pedigree and relevant reference subpopulations and (iii) assess the impact of current diversity on genomic selection. Reference 1 was Katahdins born from 2017 to 2019 (n = 23,494), while reference 2 was a subset with at least three generations of Katahdin ancestry (n = 9327). The completeness of the whole pedigree, and the pedigrees of reference 1 and reference 2, were above 50% through the fourth, fifth and seventh generation of ancestors, respectively. Effective population size (Ne) averaged 111 animals with a range from 42.2 to 451.0. The average generation interval was 2.9 years for the whole pedigree and reference 1, and 2.8 years for reference 2. The mean individual inbreeding and average relatedness coefficients were 1.62% and 0.91%, 1.74% and 0.90% and 2.94% and 1.46% for the whole pedigree, reference 1, and reference 2, respectively. There were over 300 effective founders in the whole pedigree and reference 1, with 169 in reference 2. Effective number of ancestors were over 150 for the whole pedigree and reference 1, while there were 67 for reference 2. Prediction accuracies increased as the reference population grew from 1k to 7.5k and plateaued at 15k animals. Given the large number of founders and ancestors contributing to the base genetic variation in the breed, the Ne is sufficient to maintain diversity while achieving progress with selection. Stable low rates of inbreeding and relatedness suggest that incorporating genetic conservation in breeding decisions is currently not of high priority. Current Ne suggests that with limited genotyping, high levels of accuracy for genomic prediction can be achieved. However, intense selection on GEBV may cause loss of genetic diversity long term.

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Section: Discussionsupporting

confidence: 59%

Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Pedigree diversity and implications for genetic selection of Katahdin sheep

Nilson,

Burke,

Murdoch

et al. 2023

J Animal Breeding Genetics

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Estimation of genetic parameters and the effect of inbreeding on dairy traits in Istrian sheep

Špehar

Ramljak

Kasap

2022

Italian Journal of Animal Science

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Effect of Individual Rate of Inbreeding, Recent and Ancestral Inbreeding on Wool Quality, Muscling Conformation and Exterior in German Sheep Breeds

Justinski,

Wilkens,

Distl

2023

Animals

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This study provides comprehensive results on the current status of inbreeding depression for traits upon which sheep are selected for the herdbook in Germany. A total of 30 sheep breeds from the OviCap national database met the inclusion criteria for the present analysis regarding the depth and completeness of pedigrees and the number of animals with phenotypic data. We analyzed heritabilities and inbreeding depression for the three breeding objective traits of wool quality, muscling conformation and exterior. Heritabilities were across all breeds of moderate size, with estimates of 0.18 for wool quality and muscling conformation and of 0.14 for exterior. The models employed to estimate linear regression slopes for individual and ancestral inbreeding rates also account for non-genetic effects and the additive genetic effect of the animal. Inbreeding depression was obvious for all three traits when we averaged the estimates across all 30 sheep breeds. Inbreeding depression was significant for wool quality for only a few breeds, whereas for muscling conformation, 14/30 breeds achieved significant estimates. A 1% increase in inbreeding decreased the mean of all three traits across all sheep breeds by 0.33% of their standard deviation. Positive effects due to ancestral inbreeding were only significant in very few breeds in the different traits. Across all 30 sheep breeds, there were indications that purging effects (a reduction in negative effects of inbreeding depression due to selection for heterozygotes) may play a role for the exterior. The results of this study should help for reviewing breeding programs, particularly for sheep breeds with critical effective population sizes and increasing rates of inbreeding, with regard to the selection policy and selection intensity applied.

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Pedigree analysis of Santa Inês sheep and inbreeding effects on performance traits

Cited by 5 publications

References 19 publications

Pedigree diversity and implications for genetic selection of Katahdin sheep

Pedigree diversity and implications for genetic selection of Katahdin sheep

Estimation of genetic parameters and the effect of inbreeding on dairy traits in Istrian sheep

Effect of Individual Rate of Inbreeding, Recent and Ancestral Inbreeding on Wool Quality, Muscling Conformation and Exterior in German Sheep Breeds

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