Abstract: Herpesvirus outbreaks are common in natural animal populations, but little is known about factors that favour the infection and its consequences for the organism. In this study, we examined the pathophysiological consequences of a disease probably attributable to herpesvirus infection for several markers of immune function, corticosterone, telomere length and inflammation. In addition, we assessed whether any markers used in this study might be associated with the occurrence of visible clinical signs of the disease and its impact on short-term survival perspectives. To address our questions, in spring 2015, we collected blood samples from nestlings of the magnificent frigatebird (Fregata magnificens) that were free of any clinical signs or showed visible signs of the disease. We found that the plasma concentration of haptoglobin was strongly associated with the infection status and could predict probabilities of survival. We also found that nestlings with clinical signs had lower baseline corticosterone concentrations and similar telomere length compared with healthy nestlings, whereas we did not find any association of the infection status with innate immune defenses or with nitric oxide concentration. Overall, our results suggest that the plasma concentration of haptoglobin might be a valuable tool to assess survival probabilities of frigatebird nestlings facing a herpesvirus outbreak.

Abstract: Humans have domesticated many kinds of animals in their history. Dogs and horses have particularly close relationships with humans as cooperative partners. However, fewer scientific studies have been conducted on cognition in horses compared to dogs. Studies have shown that horses cross-modally distinguish human facial expressions and recognize familiar people, which suggests that they also cross-modally distinguish human emotions. In the present study, we used the expectancy violation method to investigate whether horses cross-modally perceive human emotions. Horses were shown a picture of a human facial expression on a screen, and they then heard a human voice from the speaker before the screen. The emotional values of the visual and auditory stimuli were the same in the congruent condition and different in the incongruent condition. Horses looked at the speaker significantly longer in the incongruent condition than in the congruent condition when they heard their caretaker's voices but not when they heard the stranger voice. In addition, they responded significantly more quickly to the voice in the incongruent condition than in the congruent one. To the best of our knowledge, this is the first study to show that horses cross-modally recognized the emotional states of their caretakers and strangers.

Abstract: We examined the effects of the presence of an unfamiliar, a gentle or an aversive handler during milking on behaviour and milk yield, and whether cows can learn to approach or avoid a handler by observing the neighbouring cow?s responses. In Experiment 1, Danish Friesian cows (n=16) were treated gently (offering hay and concentrates) by one handler and aversively (hit every 15s on the head with the hand) by another handler for six periods of 2min each. The two handlers wore different coloured overalls, and each cow received either gentle or aversive treatment in the first week and the other treatment the following week. All cows kept a longer distance to the aversive than to the gentle handler in a 1min test after treatment. Milk yield and residual milk did not differ when the aversive or the gentle handler was standing in front of the cow during milking, although the cows moved their legs and tail less when the aversive handler was present. When an unfamiliar person was standing in front of the cows during milking, behaviour and milk yield did not differ from control milkings. Cows and heifers (n=10) that had observed their neighbours receiving gentle treatment by one handler and aversive treatment from another handler did not differ in the distance they kept from these two handlers. In Experiment 2, cows (n=15) that had observed the neighbours receiving a gentle treatment (eight times for 2min) kept a shorter distance to that handler after treatment of their neighbours, and the distance they kept was correlated with the distance kept by the neighbouring cows. This suggests that responses of observer cows may be affected by the responses of the cows being treated. The cows rapidly learned to avoid an aversive handler, but although the cows showed clear avoidance response to the aversive handler there was no effect on milk yield when the aversive handler was present at milking.