Animals use their sense of smell to find food, select mates, and detect predators.
Cattle, especially, have a well-developed sense of olfaction that may play a significant role in their everyday lives. Understanding their odor-related preferences and motivations could help to guide handling and management practices that could influence the physiology and health of dairy animals. For example, appealing smells could be used to motivate or calm cows in some settings.
A team of Swedish researchers recently published a study in the Journal of Dairy Science that added to the limited body of research-based knowledge regarding the olfactory abilities of cattle.
Their study included 28 lactating dairy cows – 16 Swedish Holstein and 12 Swedish Red. The cows were evaluated in pairs and exposed multiple times to four novel fragrances – cedarwood, lavender, orange, and peppermint. The odors were presented to the cows by soaking and equivalent dose of fully concentrated essential oils on clean filter paper placed in an “odor box.”
Behaviors evaluated included sniffing, licking, and biting the odor box; avoidance behavior, and ear positions in response to repeated exposure to the odors. The researchers wanted to learn whether cows were able to discriminate 4 orders of natural, non-social origin; whether any of the odors evoked more interest than the others; and if age, parity, or breed had any impact on the results.
Their findings included:
- Cows showed a numerical decrease in sniffing time over repeated presentations of the same odor. But only the first-to-third presentation of cedarwood and first-to-second and first-to-third presentation of orange differed significantly.
- Younger cows sniffed longer than older cows, irrespective of odor.
- As a whole, the cows in the study did not sniff any of the odors significantly more than others, although they did sniff cedarwood numerically more than the others, and orange the least.
- Breed did not influence sniffing behavior.
- Peppermint tended to evoke the most licking and biting.
- It was inconclusive whether cows were able to detect all 4 orders, and whether or not they were able to distinguish between the odors.
Testing cows in pairs was chosen to promote socialization and limit stress as the animals were evaluated. However, the researchers noted that the pair testing may have affected the results due to odor contamination with the partner cow’s saliva and nasal fluid.
The researchers concluded that more work discovering the olfactory abilities of cows is needed, with possible modifications in study design.
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