Skip to main content
SLU publication database (SLUpub)

Abstract

Dairy cows are sociable animals and interact with each other daily. These affiliative and agonistic interactions may impact an individual's well-being and production, e.g., milk yield. The environment an individual cow experiences involves the expressed phenotypes of genotypes carried by their social partners. These genotypes can be modelled in terms of indirect genetic effects (IGEs). IGEs have been studied thoroughly in other species, yet information on estimating IGEs for animals moving freely in a large group is still needed. This thesis explored the social behaviour of cows using data from a real-time location system installed in two commercial farms and information from the on-farm milking system from one of the farms. The impact of proximity contacts during milking on a cow's daily milk yield was investigated using milking order information from a milking parlour. Further, the information needed to estimate breeding values for indirect genetic effects was assessed with simulations. The results revealed that the total impact of the neighbours during milking on a cow´s daily milk yield could contribute to or reduce by up to 2 kg of milk. A weak negative correlation existed between the phenotypic direct and indirect effects on milk yield. The variation in indirect effects suggests room for improvement, and future research will assess a possible genetic component. How much contact a cow had with her herd mates in the barn varied between individuals and functional areas and was associated with her parity, lactation stage, reproductive status, udder health, and claw health. The results from the simulation study showed that the magnitude of the IGEs and how accurately we collect the social contacts will influence how well we can estimate IGE in dairy cattle. Collecting the intensities and direction of contacts between individuals was important for achieving better variance component estimates and breeding value accuracies of the IGE. The process of including indirect genetic effects in dairy breeding programs is expected to take time, but this thesis is a first step in approaching this.

Keywords

cow behaviour; social environment; indirect genetic effects; dairy cattle; milk yield; precision livestock farming; real-time location system

Published in

Acta Universitatis Agriculturae Sueciae
2025, number: 2025:37
Publisher: Swedish University of Agricultural Sciences

SLU Authors

UKÄ Subject classification

Animal and Dairy Science

Publication identifier

  • DOI: https://doi.org/10.54612/a.42321c0civ
  • ISBN: 978-91-8046-472-7
  • eISBN: 978-91-8046-522-9

Permanent link to this page (URI)

https://res.slu.se/id/publ/132977