Abstract: Intraspecific allometric calculations of the brain to body size relation revealed distinct differences between 127 (67; 60) ancestral wild cavies and 82 (37; 45) guinea pigs, their domesticated relatives. The dependency of both measures from one another remained the same in both animal groups but the brains of guinea pigs were by 14.22% smaller at any net body weight. Consistent with results in other species the domestication of Cavia aperea is also characterized by a decrease of brain size. Fresh tissue sizes of the five brain parts medulla oblongata, cerebellum, mesencephalon, diencephalon and telencephalon were determined for 6 cavies and 6 guinea pigs by the serial section method. Additionally the sizes of 16 endbrain structures and those of the optic tract, the lateral geniculate body and the cochlear nucleus were measured. Different decrease values resulted for all these structures concomitant with domestication as was calculated from the amount of total brain size decrease and average relative structure values in the wild as well as the domesticated brain. The size decrease of the entire telencephalon (-13.7%) was within the range of the mean overall reduction as similarly was the case for the total neocortex (-10.7%) whereas the total allocortex (-20.9%) clearly was more strongly affected. The size decrease of the olfactory bulb (-41.9%) was extreme and clearly higher than found for the secondary olfactory structures (around -11%). The primary nuclei of other sensory systems (vision, audition) were decreased to less extent (lateral geniculate: -18.1%; cochlear nucleus: -12.6%). Mass decreases of pure white matter parts were nearly twice as high in contrast to associated grey matter parts (neocortex white versus grey matter; tractus opticus versus lateral geniculate body). The relatively great decrease values found for the limbic structures hippocampus (-26.9%) and schizocortex (-25.9%) are especially notable since they are in good conformity with domestication effects in other mammalian species. The findings of this study are discussed with regard to results of similar investigations on wild and domesticated gerbils (Meriones unguiculatus), the encephalization of the wild form, the special and species-specific mode and duration of domestication and in connection with certain behavioral changes as resulted from comparative investigations in ethology, socio-biology, endocrinology and general physiology.

Abstract: Rollkur, the usually coercively obtained hyperflexion of the horse's neck, is employed as a training method by some dressage riders; however, its use is controversial as it may cause discomfort and adversely affect the horse's welfare. The objectives of this study were to determine: (1) if horses showed differences in stress, discomfort and fear responses as measured by heart rate and behaviour when ridden in Rollkur (R) obtained by pressure on the reins compared to regular poll flexion (i.e. with the nose-line being at or just in front of the vertical; N), and (2) if they showed a preference between the two riding styles when given the choice. Fifteen riding horses were ridden 30 times through a Y-maze randomly alternating between sides. Riding through one arm of the Y-maze was always followed by a short round ridden in R, whereas riding through the other arm was followed by a short round ridden in N. Immediately after the conditioning phase, horses were again repeatedly ridden into the maze; however, riders left it to the horse to decide which arm of the maze to enter. During R, horses moved slower and showed more often behavioural signs of discomfort, such as tail-swishing, head-tossing or attempted bucks (P < 0.05), and 14 of the 15 horses chose significantly (P < 0.05) more often the maze-arm associated with N rather than R. Subsequently, eight of the horses were also subjected to two fear tests following a short ride in N as well as a ride in R. During R, horses tended to react stronger (P = 0.092) to the fear stimuli and to take longer (P = 0.087) to approach them. These findings indicate that a coercively obtained Rollkur position may be uncomfortable for horses and that it makes them more fearful and therefore potentially more dangerous to ride. Further studies need to assess horses' reaction to gradual training of Rollkur, as opposed to a coercively obtained hyperflexion, in order to decide whether the practice should be banned.

Abstract: Twelve yearlings were divided into two groups and subjected to two different training schedules: (a) 30min of training daily (the daily trained group); and (b) 30min of training for 4 days, followed by a 3-day rest (the intermittently trained group), in order to compare the effect of two training methods on the ability of the horses to learn to be driven and ridden and to respond to the handlers? cues. The length of this experimental training was 17 days. The first step of training was surcingling and proceeded to lunging, to driving from the ground, and finally to being ridden at a trot on a track. Both groups were tested four times during the experimental period when they were at the same stage of training. They were driven and then ridden at a walk by a rider on a specified course and evaluated. The time to complete the course, accuracy of traveling the course, and heart rate during the test were used as the indicators of success in training. In three out of the four tests, the daily trained group tended to move faster and with more accuracy than the intermittently trained group. It would appear that daily training without a long interruption is more effective for yearlings.

Abstract: Background The frequency of serum IgA deficiency (SIgAD) differs between populations. We examined the prevalence of SIgAD in healthy Caucasians. Materials and methods Serum immunoglobulin A (SIgA) was measured in 7293 volunteers (2264 women, 5029 men) aged 30 ± 14·2 years (mean ± SD; range: 12–66). Serum immunoglobulin A and subnormal SIgA levels were defined by a SIgA level < 0·07 g L-1, and between 0·07 and 0·7 g L-1, respectively. Means were compared by analysis of variance (anova) and analysis of covariance (ancova); frequencies by the χ2 test. Results Fifteen subjects (0·21%; one woman, 14 men) had SIgAD. Subnormal SIgA levels were found in 155 persons (2·13%): 21 females (0·93% of the females) and 134 males (2·66% of the males; difference: 1·74%; 95% CI: 1·12–2·33%; P < 0·001). Males were more likely to have subnormal SIgA levels or SIgAD (odds ratio 3·09, 95% CI: 1·97–4·85). The prevalence of SIgAD and subnormal SIgA was lowest in winter (χ2 = 14·8; P = 0·002; 3 d.f.; and χ2 = 43·2; P < 0·001; 3 d.f., respectively). Serum immunoglobulin A concentrations were significantly higher during winter. Serum immunoglobulin A levels increased with age on average by 0·2 ± 0·06 g L-1 per decade of life (P < 0·001). Taking into account the influence of age, SIgA concentration was lower in females as compared with males. Conclusion The prevalence of SIgAD and subnormal SIgA levels is increased in males. There exists a significant influence of gender, age and seasons on SIgA levels.