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Comparison of fixed and random regression test day animal models in genetic evaluation of Iranian Holstein heifers for somatic cell score

Published online by Cambridge University Press:  23 November 2017

H Farhangfar*
Affiliation:
Birjand University, Birjand, Islamic Republic of Iran
A Abedini
Affiliation:
Zabol University, Zabol, Islamic Republic of Iran
P Rowlinson
Affiliation:
University of Newcastle upon Tyne, Newcastle, United Kingdom
K Shojaian
Affiliation:
Zabol University, Zabol, Islamic Republic of Iran
B Mohammad Nazari
Affiliation:
Animal Breeding Centre, Karaj, Islamic Republic of Iran
H Naeemipour
Affiliation:
Birjand University, Birjand, Islamic Republic of Iran
M.H. Fathi Nasri
Affiliation:
Birjand University, Birjand, Islamic Republic of Iran
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Extract

Mastitis has been one of the major diseases in dairy herds inducing economic costs associated with decreasing milk yield and its quality as well as increasing health care practices. In response to bacterial infection, the concentration of somatic cells increases in the milk of dairy cows (Boettcher et al., 2007). Somatic cell count has been widely utilised as an indicator trait for mastitis. Somatic cell count, like milk yield, varies with stage of lactation and more accurate genetic evaluation of dairy cows could be obtained when a test day model is used (Haile-Mariam et al., 2001). The main aim of this research was to compare fixed and random regression test day models in genetic evaluation of Iranian Holstein first lactation cows based on their predicted breeding value for somatic cell score.

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Copyright
Copyright © The British Society of Animal Science 2008

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References

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