Page 82 - NZ Hereford Magazine 2023

to my knowledge, is the largest dataset of free-ranging
cattle collected for one single research project into grazing
behaviour. Collecting a large amount of data in a relatively
short time was not only needed to conduct a genetically
sound study but also was a key factor in the success because
it reduced the ‘noise’ in the data that might interfere with
detecting genetic associations.
I combined the geolocation data with satellite data to add
the information of elevation and slope to every single point.
I then calculated several metrics of grazing behaviour, for
example, the horizontal and vertical distances travelled,
the mean elevation and slope, the home range, movement
tortuosity, elevation range, etc. Hereford cow with a self-made GPS-tracking collar installed
Based on previous research, a candidate gene of grazing around its neck being blood sampled for genetic analysis.
behaviours was selected and a set of genetic markers was
designed. One of the most critical decisions made was
selecting the right gene, and within that gene, choosing
the specific portion of DNA to genotype. For this, the
expertise from Jon Hickford and Huitong Shou from Lincoln
University’s Gene Marker Lab was essential. Each collared cow
was blood sampled for DNA genotyping of the selected gene.
In all this process, I learned many skills, from soldering
electronics, taking blood samples and extracting DNA, to
computer programming, data wrangling and data science.
WHAT WAS FOUND

The grazing personality model
The research started with a comprehensive review of literature
focused on the grazing behaviour of beef cattle, animal Cristian assembling collars for installation on cows: GPS devices’
personality theory, and behavioural genetics. This led to a settings are double-checked with the laptop, plugged in to their
research hypothesis presented in a conceptual model called corresponding batteries, and sealed into the watertight container
the ‘grazing personality model’ (GP-Model). of collars. Boxes, collars and tools were disinfected before each
Briefly, the GP-Model proposes that grazing genes farm visit.
determine a set of traits that ultimately lead to distinctive
grazing personalities observed in social foragers. This genetic
determination of behaviour is mediated by a regulatory
system that includes the biophysical environment, the social
environment of the herd and the animals’ emotional state
and cognition. Cows with different genotypes may show
different sets of grazing behaviours called individual grazing
personalities. Due to the flexible gene expression, individuals
with different genotypes may show very distinctive grazing
personalities or may show similar and overlapping behaviours.
Furthermore, the GP-Model also proposes that the relative
representation of genotypes within a herd determine the
grazing personality of the group (referring to the particular
way a herd of animals graze a certain area) called the collective
grazing personality.
The grazing personality concept is applicable at the
individual and collective levels of large herbivores and it
refers to sets of grazing behaviours consistently repeated
over time and across different situations. Grazing personality
can be understood as the grazing signature of individuals or
groups of foragers. Details and examples were presented in
the publication ‘On the Search of Grazing Personalities: from
1
Individual to Collective Behaviours’ . See Figure 1: The Grazing
Personality Model (GP-model).

Genetic associations with grazing behaviours Cristian loading amplified DNA samples to determine the
The study revealed genotype-phenotype associations between genotype within the grazing gene of each cow at the Gene
five genotypes of the glutamate metabotropic receptor 5 gene Marker Lab of Lincoln University.

80 HEREFORD MAGAZINE Year 2023