Abstract: A feral horse population inhabiting the Vodnyi Isl, Manych-Ghudilo Lake, on the territory of Rostov Region, S Russia, has been established in 1950s according to questionnaire data (Paklina, Klimov, 1990). It is a sole permanent grouping of feral horse known to exist in European Russia (Spasskaya, Spasskyi, 2007; Spasskaya, 2008). Range of this group is part of Federal Reserve “Rostovsky” established in 1995, and its monitoring has being been conducted since 2006. The principal aim of monitoring includes gathering data on demographic, spatial, and ethological structure of the island horse population, along with investigation of its phenotypic and ethological patterns. Analysis of previously published (Paklina, Klimov, 1990) and recently obtained data on the color patterns of the island horse indicate that they have become isolated supposedly about 18–20 years ago. Some trends in variation of several phenotypic traits indicate slight rising of inbreeding level in this population, including decrease in the horse withers height, changes in body proportions, increase of heterogeneity in body color patterns (size and number of head and leg spots), and increase of frequency of dental malformations, especially of false polydonty of P1 (Spasskaya et al., 2010). Principal demographic parameters of this population are similar in general to those known for other feral horse studied by now. However, several peculiar features of this population were revealed: its age structure appeared to be of steadily fading type judging by high proportion of mature individuals (64–72 %); high mortality rate of individuals of the first year of life (16–25 %); predominance of males among newborns with increase of population size. Ethological structure of the population included standard harem bands and bachelor groups, with few solitary animals (usually old or sick stallion). The most of individuals (58.2–84.3 %) were the part of harem bands, which appeared to be the most stable groupings. The harems were small in their numbers with predominatingly 3–8 individuals. The bachelor groups were inconstant in composition, their portion in population being not high (7.7–15.4 % of the total number). A lot of “mixed” groupings of various composition were recorded in the population during its high number phase: harem bands with several mature stallions; associations consisting of several harem bands; youth groupings consisting of approximately coeval stallions and mares. These “mixed” groupings appeared to be rather stable, with their total number reaching up to 25.8 % of the population. They however used to disappear with population number decrease. The Rostov population is characterized by absence of conspicuous home range of social groupings (Spasskaya, Shcherbakova, 2007; Spasskaya, 2009), so the latter form a united herd with minimal intergroup distances. This phenomenon is probably not related to population density or to the island size, but is rather caused by some other factors to be revealed.

Abstract: Abstract Missing KW -

Abstract: Abstract Missing KW -

Abstract: Among mammals, lactation is the most energy demanding part of parental care and so parentoffspring conflict should arise over milk provided by the mother. Mother and offspring should disagree over the length and amount of the milk provision. We focused on effect of pregnancy on suckling behaviour variables as indicators of mother-offspring conflict in domestic horses. We presumed shorter suckling bouts and higher rates of rejected and/or terminated suckling in pregnant mares compared to non-pregnant ones. Increasing conflict over amount of maternal investment between mother and her young are to be expected because of her parallel investment into a nursed foal and a foetus. Eight groups of loose housed lactating mares with foals of Kladruby horse were studied at the National Stud Kladruby nad Labem (Czech Republic) from deliveries to abrupt weaning (at the age of 127 to 210 days). We recorded 10 848 suckling solicitations of 79 mare-foal pairs, from which 10 607 resulted in a suckling bout. In 41 cases a nursing mare became pregnant during lactation. We found no significant effect of pregnancy either on probability of the mother rejecting suckling solicitation of her foal or probability that she terminated a suckling bout. However the overall effect of mother’s pregnancy on suckling bout duration was not significant, there were considerable differences in pregnant and non-pregnant mares according to who terminated a suckling bout, whether the mother or the foal (F(1, 9776) = 12.1, P < 0.001). In case it was the mother then the suckling bout was longer if she was pregnant (65.36 ± 1.25 s) than barren (60.55 ± 1.36 s). We found no impact of pregnancy on duration of suckling bouts terminated by the foal. Further, nursing a foal during the first two trimesters of pregnancy had no negative impact on birth weight of the foetus. In conclusion, we found not higher, but a lower mother-offspring conflict in pregnant than in non-pregnant lactating mares while expecting just the opposite. We suggest that pregnant mares compensate their nursed foals during intensive stages of lactation through a relaxed mother-offspring conflict for later decrease in investment due to increasing demands of the foetus and/or for the shorter period of milk supply. Our results (partly published in Bartosova et al. 2011, PLoS ONE 6(8): e22068) are of high importance in horse breeding. One of the main arguments for early weaning of the foals is regeneration of their pregnant mothers before upcoming delivery. Here we present evidence that a pregnant mare “counts” with her dual maternal investment and “employs” evolutionary mechanisms enabling her to rear a vital foetus. From this point of view there is no objective reason for stressful weaning of her nursed offspring practised in conventional breeding. Supported by AWIN, EU FP7 project No. 266213.

Abstract: Animals with eyes placed laterally on their head would respond differently to stimuli detected on their different sides. Visual cues from the left eye are processed in the right hemisphere which controls the intensive emotion expression and fast response to the stimuli, while the left hemisphere receiving the information from the contralateral eye is responsible for the routine behaviour and concentration. Different use of left/right eye for exploring environment and evaluation of different stimuli was recently described in domestic horses. They use left eye predominantly for watching novel object or frightening stimulus which indicates specialization of right hemisphere (RH) for appraisal of these types of stimuli. We presumed such lateralisation also in foals during suckling when only monocular vision can be employed for observing surroundings (foals suck mostly in antiparallel body position). Two mutually exclusive hypotheses about the origin of probable foal’s preference for particular suckling side were postulated: 1) visual lateralization, then the foals should suck more often from the mother’s right side (‘from right’), so as potential danger would be detected by the better adapted right hemisphere (i.e. left eye); 2) motor lateralization (the analogous concept as human “handness”), then a foal should suck predominantly from one side, either left or right, more often. Within two seasons, suckling behaviour of 59 Kladruby mares giving birth to 79 foals was observed from deliveries to abrupt weaning (4-7 months of age). From 10 607 recorded suckling solicitations, 50.2% were performed from right, thus there was no preference of the suckling side on a population level. However, we found large variability in the probability of suckling from right among individual foals (p<0.0001); the probability ranged from 0.22-0.98. One third of the foals (35.4%) showed strong, either right (N=13) or left (N=15) side preference which further strengthened with age (interaction suckling side preference*foal’s age: p<0.0001). Other tested variables, i.e. sex of the foal, age of the mother and identity of the herd were not significant. The probability that the mother rejected foal’s suckling solicitation (N=108) did not differ according to the suckling side (right/left) or suckling side preference (right/left/no preference). Suckling bout duration was not significantly influenced neither by the suckling side nor suckling side preference regardless the mother or the foal terminated the suckling bout. In conclusion, only 16 % of the foals revealed significant right side preference for suckling while 19 % left side and 65 % no preference. Thus, we can reject the visual hypothesis because a general trait to suck with left eye open for better danger detection and recognition is unlikely to occur, at least in up to 7 months old foals. Such a young foal is probably fully focused on suckling and relies on mother’s vigilance. Observed individual side preferences indicated more likely a kind of motor lateralization in part of the foals. Further research is needed to clear up the effects of age and individual experience of the foal. Supported by AWIN, EU FP7 project No. 266213.