Increased rates of involuntary culling as a consequence of poorer health and fertility
had led to the conclusion that dairy cows appear to be less “robust” or adaptable than
in the past. A way to address these concerns in breeding programs could be to select
for health and welfare by including appropriate traits in a broader breeding index.
However, it is important to consider any consequences that such breeding goals may
have on dairy cow temperament and welfare. There were two phases to this study.
The main objective of phase I was to develop tests for measuring responsiveness to
humans and novelty, aggression at the feedface and sociability in dairy cows for use
on commercial farms. To allow these tests to be used on commercial farm, they must
be short in duration, non-invasive and not disruptive to the daily farming routine,
while at the same time allowing comparisons between an individual cow’s responses
in a number of similar situations.
Results from this study suggested that a standardised human approach test and a
stationary visual object are reliable tests for measuring responsiveness of dairy cows
to changes in their environment. Measuring behaviour at the feedface proved to be an
effective measure of between cow aggression. Inter-animal distance, position in
relation to the herd, behavioural synchrony and presence at the feedface proved
accurate measures of sociability. The remaining part of the study (Phase II) focussed
on assessing how the implantation of a breeding index can affect the temperament of
dairy cows on commercial farms. The tests developed were then recorded on 402
first lactation Holstein-Friesian dairy cows selected from sires that scored high (HI)
and low (LO) for robustness (health, fertility and longevity traits) to produce two
treatment groups on 33 commercial farms. For the purpose of this thesis, only the
results from the assessment of aggressiveness are presented. Continuous focal
sampling was used to record aggressive behaviour during feeding of the HI and LO
cows within the herd. Cows from the HI group were involved in more aggressive
interactions, initiated more aggression and received more aggression than cows from
the LO group. There was a strong influence of management factors influencing
aggression such as the quality of stockmanship, feedface design and nutrition.
In conclusion, daughters from sires scoring high for robustness may be expressing a
greater ability to maintain position at the feedface during an aggressive interaction.
This highlights the importance of assessing the correlated effects of selective
breeding, in this case for robustness, on behavioural traits
