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A major task when developing methods of assessing animal welfare is to identify observable external indicators of internal subjective feelings. In this paper, we tested the hypothesis that the percentage of white in the eyes would change as a response to two emotional stimuli; waiting to be fed concentrate and acquiring this food. Twelve dairy cows in a tie-stall were observed for eye-white percentage and behaviour (continuous sampling), one trial day per cow, in a standard daily situation in which a stockman entered the house and fed all animals with concentrate feed within 10 min. The eye-white percentage increased significantly, although moderately, during the first minute and was kept moderately high during the waiting period. After food was obtained, the eye-white percentage decreased compared to the base level. We suggest that a high eye-white percentage may reflect a strong emotional response.

The present experiment aimed at investigating the generality of the percentage of visible eye-white as a dynamic indicator of frustration and satisfaction. In this experiment, we used separation of 11 multiparous dairy cows from their 4 days old calf as a frustrating stimulus, and reunion with the calf as a rewarding stimulus. We hypothesized that the eye-white percentage of the cow would increase when the calf was taken away from her, and decrease when cow and calf were reunited. The eye-white percentage was larger when cows were separated from their calf compared to when they were reunited with the calf. The hypothesis was therefore not falsified. The present results strengthen the assumption that this behaviour element may be a general dynamic indicator of emotions in dairy cattle.

The present experiment compared the anxiety- and activity-related behaviour of sub-adult females from a mouse strain selected for over 106 generations for high litter size with that of a randomly selected control strain, to illuminate possible differences in their ability to cope with exposure to a novel environment. Selected for large litter size, the H-strain has an average litter size of 21 pups, whereas the randomly bred C-strain has an average litter size of 10 pups. The elevated plus-maze was used to measure the behaviour of the mice expressed in response to novelty. The results are described and discussed in relation to the ability to cope with novel environmental challenges. In the elevated plus-maze, the H-strain was significantly more anxious (having a lower percentage of entries into and percentage of time spent on open arms) and less active (having a lower number of entries into closed arms, and a lower total number of arm entries) than the C-strain. Thus, there were clear anxiety- and activity-related differences between the strains, which may be related to selection for large litter size. A tentative hypothesis is presented whereby selection for large litter size may accelerate adaptation to the home environment, but decrease the ability of selected animals to cope with exposure to novelty.