Use of descriptors to define clusters of herds under similar environmental conditions to improve the level of connection among contemporary groups of mutton type merino sheep under an extensive production system

Osorio-Ávalos, Jorge; Menéndez-Buxadera, A.; Serradilla, J. M.; Molina, A.

doi:10.1016/j.livsci.2015.03.029

Cited by 8 publications

(9 citation statements)

References 18 publications

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“…Thus, it is essential to know genetic associations between the economic importance traits in the reason that they are correlated in magnitude and direction (Sonesson and Meuwissen 2000;Savegnago et al 2011;Porto-Neto et al 2013;Osorio-Avalos et al 2015). Thus, multivariate statistical techniques might generate not possible interpretations if univariate statistics was used.…”

Section: Introductionmentioning

confidence: 99%

Principal component and cluster analyses of production and fertility traits in Red Sindhi dairy cattle breed in Brazil

Mello

Sinedino

Ferreira

et al. 2019

Trop Anim Health Prod

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The objective of this study was to investigate the relationship among functional traits (age at first calving (AFC), calving interval (CI), reproductive efficiency (RE), total milk yield (TMY), and lactation period (LP)) in Red Sindhi breed through multivariate techniques. For this goal, performance data provided by the Brazilian Association of Zebu Breeders related to 560 Red Sindhi dairy cattle from 28 different herds in Brazil, born in the period from 1987 to 2011, were used. Principal component analysis with correlation matrix was used to find the relationship among AFC, CI, RE, TMY, and LP. It was found that for all functional traits, first 3 principal components explained more than 90% of the total variation. Clustering analysis was performed based on Tocher method, and results showed physiological relationships among functional traits. By cluster analysis, twelve different groups were generated from the pool of Sindhi herds analyzed, with a great homogeneity among females for the traits evaluated and only few females generating separate groups. Four hundred and twenty-nine females were clustered in one group, representing 76.60% of the genotypes. Total milk yield (TMY) showed 71.92% of the total variation, and age at first calving (AFC) contributed with 23.06% of the variation, being the two most important traits for the variability of the data set. In conclusion, the multivariate procedures were effective in generating the correlations among the functional traits, showing that CI is correlated with RE and all these functional traits are related with total milk yield.

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Section: Introductionmentioning

confidence: 99%

Principal component and cluster analyses of production and fertility traits in Red Sindhi dairy cattle breed in Brazil

Mello

Sinedino

Ferreira

et al. 2019

Trop Anim Health Prod

View full text Add to dashboard Cite

show abstract

“…Regarding sires, the increase was 5.1 % (herd-cluster test day) and 5.7 % (herd-cluster test month). Hence, the detailed consideration of environmental conditions and herd characteristics contributed to an increase of EBV reliabilities in the range from 3 % to 6 %, reflecting the postulations by Zwald et al (2003) and Osorio-Avalos et al (2015). The herd cluster instead of the herd effect for the CG modeling contributed to increased heritability estimates from 0.23 (herd-test-day effect and herd-test-month effect, respectively) to 0.36 (herdcluster-test-day effect) or to 0.38 (herd-cluster-test-month effect).…”

Section: Impact Of Herd Clustering On Genetic Evaluationsmentioning

confidence: 99%

“…The influence of the herd effect when modeling CGs is not constant throughout the year, implying consideration of a further time-dependent explanatory variable, i.e., via herd-year-season or herd-test-day modeling (Emmerling, 2000). However, such modeling approaches might be problematic in the case of small herd sizes, implying only a few cow records per CG, with detrimental impact on selection accuracy (Strabel et al, 2005;Pereira et al, 2018). Furthermore, human-animal relationships reflecting social characteristics determine herd effects.…”

Section: Introductionmentioning

confidence: 99%

Herd clustering strategies and corresponding genetic evaluations based on social–ecological characteristics for a local endangered cattle breed

2021

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Abstract. The accuracy of breeding values strongly depends on the population and herd structure, i.e., the number of animals considered in genetic evaluations and the size of contemporary groups (CGs). Local breeds are usually kept in small-sized family farms under alternative husbandry conditions. For such herd structure, consideration of classical herd or herd-test-day effects in CG modeling approaches implies only a few records per effect level. In consequence, the present study aimed on methodological evaluations of different herd clustering strategies, considering social–ecological and herd characteristics. In this regard, we considered 19 herds keeping cows from the small local population of German Black Pied cattle (Deutsches Schwarzbuntes Niederungsrind; DSN), 10 herds keeping Holstein Friesian (HF) cows and one mixed herd with HF and DSN cows. Herds were characterized for 106 variables, reflecting farm conditions, husbandry practices, feeding regime, herd management, herd fertility status, herd health status and breeding strategies as well as social–ecological descriptors. The variables were input data for different clustering approaches including agglomerative hierarchical clustering (AHC), partition around medoids (PAM), fuzzy clustering (FZC) and a clustering of variables combined with agglomerative hierarchical clustering (CoVAHC). The evaluation criterion was the average silhouette width (ASW), suggesting a CoVAHC application and consideration of four herd clusters (HCs) for herd allocation (ASW of 0.510). HC1 comprised the larger, half organic and half conventional DSN family farms, which generate their main income from milk production. HC2 consisted of small organic DSN family farms where cows are kept in tie stables. HC3 included the DSN sub-population from former East Germany, reflecting the large-scale farm types. The specialized HF herds were well separated and allocated to HC4. Generalized linear mixed models with appropriate link functions were applied to compare test-day and female fertility traits of 5538 cows (2341 DSN and 3197 HF) from the first three lactations among the four HCs. Least squares means for milk, fat and protein yield (Mkg, Fkg and Pkg) significantly differed between HC. The significant differences among the four HCs clearly indicate the influence of varying herd conditions on cow traits. The similarities of herds within HC suggested the application of HCs in statistical models for genetic evaluations for DSN. In this regard, we found an increase of accuracies of estimated breeding values of cows and sires and of heritabilities for milk yield when applying models with herd-cluster-test-day or herd-cluster-test-month effects compared to classical herd-test-day models. The identified increase for the number of cows and cow records in CG due to HC effects may be the major explanation for the identified superiority.

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“…The cluster is a grouping procedure that may be attractive for defining herds under similar environmental conditions (Weigel and Rekaya 2000), which have been recently integrated using climate, management and productive variables (environmental descriptors), allowing the identification with greater clarity of environmental levels (Osorio-Avalos et al 2015), making the characterization of the production systems of a region and/or country more reliable.…”

Section: Introductionmentioning

confidence: 99%

Prevalência E Fatores De Risco Associados À Infecção Pelo Vírus Da Artrite Encefalite Caprina Em Caprinos No Estado Do Maranhão

Costa¹,

Melo²,

Silva³

et al. 2020

A Pesquisa Nos Diferentes Campos Da Medicina Veterinária 3

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Use of descriptors to define clusters of herds under similar environmental conditions to improve the level of connection among contemporary groups of mutton type merino sheep under an extensive production system

Cited by 8 publications

References 18 publications

Principal component and cluster analyses of production and fertility traits in Red Sindhi dairy cattle breed in Brazil

Principal component and cluster analyses of production and fertility traits in Red Sindhi dairy cattle breed in Brazil

Herd clustering strategies and corresponding genetic evaluations based on social–ecological characteristics for a local endangered cattle breed

Prevalência E Fatores De Risco Associados À Infecção Pelo Vírus Da Artrite Encefalite Caprina Em Caprinos No Estado Do Maranhão

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