Abstract: We examined whether very young dairy calves are able to discriminate between two people, and whether they use the colour of clothing or other indices to do so. During the familiarisation phase, one person (the familiar rewarder), who always wore the same colour clothes, gave milk, spoke gently and patted the calves in their individual pen for 6 days each week. During the test phase, the calf had to make a choice in an Y-maze placed in front of the gate of its stall. When the calves chose the familiar rewarder, they received 200 ml of milk as reinforcement. When they made the incorrect choice, they received nothing and were returned to their stall. On each test day, the calves made eight choices. The criterion of success was that the calf made at least six correct choices in eight trials on each of two consecutive test days (P<0.021 by the binomial law). The first experiment was carried out with fourteen 1-week-old male and female Holstein calves to see if calves could approach a person, who changed position in the maze, in order to obtain a feed reward. The familiar rewarder wore the same clothes as during the period of familiarisation and was in one arm of the Y-maze. The other arm was empty and the position of the familiar rewarder in the maze was randomised. Eleven of the 14 calves reached the criterion for success, after only three tests. The second experiment, carried out with five 2-week-old calves, examined whether the calves can differentiate the familiar rewarder (wearing the same clothing as during the period of familiarisation) from another person (the non-rewarder) wearing clothes of a different colour. The criterion of success was reached by all five calves. The third experiment was carried out with seven 2-week-old calves. It examined whether the calves can differentiate the familiar rewarder and the non-rewarder, when the two people are wearing clothes of the same colour (i.e. the same colour worn by the familiar rewarder during the phase of familiarisation). None of the calves were able to reach the criterion of success within a limited number of four test days. Often, calves would always choose the same arm of the maze. The fourth experiment was carried out on six 1-month-old calves. It was similar to experiment 3 with the difference that the familiar rewarder and the non-rewarder both wore the same colour clothes, but which were not the same colour as worn during the phase of familiarisation. Only one calf achieved the criterion of success within two test days. Results demonstrated that colour cues help very young calves to discriminate between two people, when these people wear different colour clothing. Some calves may be able to use other indicators than the colour of clothing. The Y-maze method is an promising way of examining calves' abilities to recognise people.

Abstract: This paper reports the first isolation of Jamestown Canyon (JC) virus from coastal California and the results of tests for antibody to JC virus in mammals living in coastal California. The virus isolation was made from a pool of 50 Aedes dorsalis females collected as adults from Morro Bay, San Luis Obispo County, California. The virus isolate was identified by two-way plaque reduction-serum dilution neutralization tests done in Vero cell cultures. Sera from the mammals were tested for antibody to JC virus by a plaque-reduction serum dilution neutralization method. A high prevalence of JC virus-specific antibody was found in horses and cattle sampled from Morro Bay. This finding is additional evidence for the presence of a virus antigenically identical or closely related to JC virus in Morro Bay and indicates that the vectors of the virus in Morro Bay feed on large mammals. A high prevalence of virus-specific antibody was also found in horses sampled from Marin and San Diego counties. This finding suggests that viruses antigenically identical or closely related to JC virus are geographically widespread in coastal California.

Abstract: The term `leadership' has been used in several different senses, resulting in very different ways of identifying leaders and apparently inconsistent conclusions on how leadership is determined in herbivores. We therefore propose the following definitions: (i) a leader is the individual that is consistently the one who initiates long-distance, spontaneous group movements toward a new feeding site and (ii) long-distance spontaneous group movements are movements which happen when an animal changes activity and location and is immediately followed by a similar change in activity and location by other members of the group. Using these definitions, we tested for consistency of movement order across time and situation within a group of fifteen 2-year-old heifers. We found that the same individual was recorded as the very first animal in 48% of movements toward a new feeding site and could therefore be identified as the `leader'. We also showed that movement order when the animals entered an experimental plot, or progressed slowly through the field during a grazing bout, did not produce the same result. This method, which enables us to identify leaders in groups of animals at pasture, should improve our knowledge of how leadership is determined in grazing herbivores.

Abstract: The role of dominant individuals in leading groups of animals is not yet well understood. We investigated whether dominant beef cows, Bos taurus, have more influence on herd movement on pasture than more subordinate cows. A herd of 15 Gasconne cows was observed for a 3-week period between dawn and dusk. The positions of all adult cows were recorded with GPS collars at 1 min intervals and the behaviour of each cow was recorded in 5 min scans. The dominance hierarchy was recorded by ad libitum sampling. Through cluster analysis of the recorded data, we distinguished three herd behaviour patterns: resting, foraging and travelling. Dominant cows were closer to the front of the herd during both travelling and foraging. During travelling, more dominant cows also had more direct trajectories and were more aligned both with their nearest neighbours and with the whole herd. During foraging, the trajectories of dominant cows were shorter than those of subordinate cows. The results indicate that foraging and short-distance travelling movements by female beef cattle are not led by any particular individual but rather are influenced by a graded type of leadership; that is, the more dominant a cow is, the stronger the influence it may have on the movements of the herd.

Abstract: The most universal approach to the studies of metal binding properties of single-site metal binding proteins, i.e., construction of a “phase diagram” in coordinates of free metal ion concentration-temperature, has been applied to equine lysozyme (EQL). EQL has one relatively strong calcium binding site and shows two thermal transitions, but only one of them is Ca(2+)-dependent. It has been found that the Ca(2+)-dependent behavior of the low temperature thermal transition (I) of EQL can be adequately described based upon the simplest four-states scheme of metal- and temperature-induced structural changes in a protein. All thermodynamic parameters of this scheme were determined experimentally and used for construction of the EQL phase diagram in the pCa-temperature space. Comparison of the phase diagram with that for alpha-lactalbumin (alpha-LA), a close homologue of lysozyme, allows visualization of the differences in thermodynamic behavior of the two proteins. The thermal stability of apo-EQL (transition I) closely resembles that for apo-alpha-LA (mid-temperature 25 degrees C), while the thermal stabilities of their Ca(2+)-bound forms are almost indistinguishable. The native state of EQL has three orders of magnitude lower affinity for Ca(2+) in comparison with alpha-LA while its thermally unfolded state (after the I transition) has about one order lower (K = 15M(-1)) affinity for calcium. Circular dichroism studies of the apo-lysozyme state after the first thermal transition show that it shares common features with the molten globule state of alpha-LA.