Spatial modelling in genetic evaluation of South African Holstein cattle population

Isidore Houaga; Thiago De Paula Oliveira; Ivan Pocrnic; Eva Lavrencic; C. B.  Banga; Gregor Gorjanc

Spatial modelling in genetic evaluation of South African Holstein cattle population

Isidore Houaga^*, Thiago De Paula Oliveira, Ivan Pocrnic, Eva Lavrencic, C. B. Banga , Gregor Gorjanc

^*Corresponding author for this work

Research output: Contribution to conference › Paper › peer-review

Abstract / Description of output

African dairy production systems are characterized by small herd size and low genetic connectedness between herds. This situation makes it difficult to accurately estimate environmental and genetic effects. We evaluated how accounting for spatial relationship between neighbouring herds impacts genetic evaluation of 305-days milk yield in South African Holstein cattle population. We analysed 305-days milk yield and pedigree data for 98,632 Holstein cows collected between 1957 and 2014 from 1,145 herds. Herd and herd-year effects were modelled as independent, whereas spatial effects were modelled as correlated between regions using the Besag model. The results show a regional variation of estimated breeding values and separation of spatial effect from herd effect. The spatial modelling of herd as random effect showed similar accuracy compared to modelling herd-year. Further studies integrating the genotype-by-environment interactions will be needed to better explore the benefits from spatial modelling in African smallholder dairy farming systems.

Original language	English
Publication status	E-pub ahead of print - 7 Jul 2022
Event	World Congress on Genetics Applied Livestock Production - Rotterdam, Netherlands Duration: 3 Jul 2022 → 8 Jul 2022 https://wcgalp.com/

Conference

Conference	World Congress on Genetics Applied Livestock Production
Country/Territory	Netherlands
City	Rotterdam
Period	3/07/22 → 8/07/22
Internet address	https://wcgalp.com/

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37_009Accepted author manuscript, 304 KBLicence: Creative Commons: Attribution (CC-BY)

https://wcgalp.com/scientific-programme

ISP 2017/22-Gregor Gorjanc
Gorjanc, G.
BBSRC
1/04/17 → 31/03/22
Project: Research

Cite this

@conference{a9c3fe4b205a44998cbfccbb0901238e,

title = "Spatial modelling in genetic evaluation of South African Holstein cattle population",

abstract = "African dairy production systems are characterized by small herd size and low genetic connectedness between herds. This situation makes it difficult to accurately estimate environmental and genetic effects. We evaluated how accounting for spatial relationship between neighbouring herds impacts genetic evaluation of 305-days milk yield in South African Holstein cattle population. We analysed 305-days milk yield and pedigree data for 98,632 Holstein cows collected between 1957 and 2014 from 1,145 herds. Herd and herd-year effects were modelled as independent, whereas spatial effects were modelled as correlated between regions using the Besag model. The results show a regional variation of estimated breeding values and separation of spatial effect from herd effect. The spatial modelling of herd as random effect showed similar accuracy compared to modelling herd-year. Further studies integrating the genotype-by-environment interactions will be needed to better explore the benefits from spatial modelling in African smallholder dairy farming systems.",

author = "Isidore Houaga and {De Paula Oliveira}, Thiago and Ivan Pocrnic and Eva Lavrencic and Banga, {C. B.} and Gregor Gorjanc",

year = "2022",

month = jul,

day = "7",

language = "English",

note = "World Congress on Genetics Applied Livestock Production<br/> ; Conference date: 03-07-2022 Through 08-07-2022",

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TY - CONF

T1 - Spatial modelling in genetic evaluation of South African Holstein cattle population

AU - Houaga, Isidore

AU - De Paula Oliveira, Thiago

AU - Pocrnic, Ivan

AU - Lavrencic, Eva

AU - Banga , C. B.

AU - Gorjanc, Gregor

PY - 2022/7/7

Y1 - 2022/7/7

N2 - African dairy production systems are characterized by small herd size and low genetic connectedness between herds. This situation makes it difficult to accurately estimate environmental and genetic effects. We evaluated how accounting for spatial relationship between neighbouring herds impacts genetic evaluation of 305-days milk yield in South African Holstein cattle population. We analysed 305-days milk yield and pedigree data for 98,632 Holstein cows collected between 1957 and 2014 from 1,145 herds. Herd and herd-year effects were modelled as independent, whereas spatial effects were modelled as correlated between regions using the Besag model. The results show a regional variation of estimated breeding values and separation of spatial effect from herd effect. The spatial modelling of herd as random effect showed similar accuracy compared to modelling herd-year. Further studies integrating the genotype-by-environment interactions will be needed to better explore the benefits from spatial modelling in African smallholder dairy farming systems.

AB - African dairy production systems are characterized by small herd size and low genetic connectedness between herds. This situation makes it difficult to accurately estimate environmental and genetic effects. We evaluated how accounting for spatial relationship between neighbouring herds impacts genetic evaluation of 305-days milk yield in South African Holstein cattle population. We analysed 305-days milk yield and pedigree data for 98,632 Holstein cows collected between 1957 and 2014 from 1,145 herds. Herd and herd-year effects were modelled as independent, whereas spatial effects were modelled as correlated between regions using the Besag model. The results show a regional variation of estimated breeding values and separation of spatial effect from herd effect. The spatial modelling of herd as random effect showed similar accuracy compared to modelling herd-year. Further studies integrating the genotype-by-environment interactions will be needed to better explore the benefits from spatial modelling in African smallholder dairy farming systems.

M3 - Paper

T2 - World Congress on Genetics Applied Livestock Production<br/>

Y2 - 3 July 2022 through 8 July 2022

ER -

Spatial modelling in genetic evaluation of South African Holstein cattle population

Abstract / Description of output

Conference

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Projects

ISP 2017/22-Gregor Gorjanc

Cite this