Method of experimentation
The study was conducted at Vasen Dairy Farm in Nye, Jönköping county, Sweden. The farm maintains approximately 450 dairy cows. The age at which newborn calves could stand up and suckle the artificial teat for the first time without lifting assistance was recorded for 78 individuals. Of these, 51 calves participated in the taste and odor experiment, with each calf being tested for 10 consecutive days.
Odor and taste responsiveness tests
The odor and taste tests were performed in order to assess whether the calves showed a preference for suckling a plain (control) dry teat versus a dry teat that was modified with a presumably attractive odor or taste.
A two-choice test apparatus was used for the study that could be adapted to the requirements of both tests and that allowed the simultaneous presentation of the control and the modified teat to the calf.
For the odor test, the modified teat consisted of a plain teat with an open petri dish positioned above it, which contained a filter paper impregnated with the odor "Freshly Cut Grass Fragrance Oil". The odor was selected as a presumably attractive olfactory stimulus according to the fact that grass is an important part of cattle diet and volatile compounds from grass feed are transferred to the fetus through circulation during gestation, as well as to the milk that calves will subsequently consume at least during the first days of life.
For the taste test, the modified teat consisted of a plain teat dipped in water and then coated with glucose. The rationale behind choosing glucose was that sweet substances are rewarding for calves and glucose specifically is frequently available in dairy farms for the preparation of electrolyte solutions for calves.
During testing, I recorded which teat the calf chose to investigate first (sniff, touch with the lips or lick the tip of a teat, or immediately suckle a teat). Using stopwatches, I also recorded suckling time (in seconds) for each teat (control, modified).
Here is how the odor test was performed (left teat on the apparatus is the odor teat):
Here is how the taste test was performed (right teat on the apparatus is the taste teat):
Responsible for this page: Agneta Johansson
Last updated: 05/13/17