News From Agriculture And Life Sciences Division, Lincoln University
Is that cow too hot?
By Janette Busch
Lincoln University Bachelor of Science honours student Amy Smaill investigated the reliability of a current method for
continuously measuring body temperature of dairy cows.
This work contributes to a much larger project funded by Dairy InSight that involves other scientists from Lincoln
University and AgResearch in the study of possible stressful effects of weather on dairy cows in some parts of New
Zealand.
“Environmental stress on lactating dairy cows has implications for milk production as well as for the welfare of
individual cows,” said Associate Professor Graham Barrell from the Agriculture and Life Sciences Division at Lincoln
University who supervised Amy’s work.
“Overseas studies have shown that milk production can decrease when cows are subject to high summer temperatures.
However, those studies have been largely based on cows fed indoors so it is important to investigate our own pasture-fed
cows on local farms to find out how well they respond to temperature stress,” he said.
Amy used small data loggers to measure body temperature simultaneously at different sites within cows and sheep - namely
the vagina and rectum - in order to determine that the vagina (convenient site) gave results similar to the rectum
(conventional site) over periods of time from two to five and a half hours.
She tested whether the temperatures at these sites differed when external conditions were changed, e.g. during drinking
of cold water, or during a fever.
“It is important to use a site where the temperature readings are unaffected by external changes in the environment, but
is easily accessible to farm staff and does not require an incision,” said Amy
“By confirming that this site (vagina) gave temperature readings that are identical to those recorded at the rectum, our
monitoring work becomes a lot easier to perform and in this way Amy’s work has made an important contribution to the
larger research project,” said Dr Barrell.
Other research in this project will be used to define critical weather thresholds and other circumstances in which
management factors could be instigated to minimize the possible negative effects of weather on the productivity and
welfare of dairy cows.
A limitation of this method for recording body temperature is that it can only be applied to female animals, however,
that is obviously not a problem in relation to dairy production.
When Amy presented her results at a recent postgraduate conference she was awarded a prize for the high quality of her
presentation.
All the work was carried out with approval of the Animal Ethics Committee.
ENDS