Development of Deep and Upper Neuronal Layers in the Domestic Cat, Sheep and Pig Neocortex.

The neocortex plays a key role in cognition, volitional motor control and sensory perception and has undergone tremendous expansion during evolution. The mature neocortex consists of radially aligned neurons that are arranged in six layers. Layers II-VI are often split into two groups: deep and upper layers, both building up the so-called cortical plate during embryonic and foetal development. So far cortical neurogenesis, including the generation of deep and upper layers, has mostly been studied in laboratory rodents and primates. However, precise data for most companion animals are lacking. This study determined the main period of neurogenesis, specifically the timing of deep and upper layer generation, in the developing domestic cat, pig and sheep neocortex using immunohistochemistry for specific neuronal markers, that is Tbr1 and Brn2. We found that the general sequence of neural events is preserved among cat, pig, sheep and other mammalian species. However, we observed differences in the timing of the overall cortical neurogenic period and occurrence of distinct neural events when these three species were compared. Moreover, our data provide further evidence that the cortical neurogenic period and gestation length might be tightly related. Together, these data expand our current understanding of neocortex development and are important for future studies investigating neocortex development and expansion especially in companion animals.

[Physiology and pathology of reproduction in domesticated New World camelids with special emphasis on ultrasonography]. / Physiologie und Pathologie der Fortpflanzung bei weiblichen, domestizierten Neuweltkameliden. Übersicht mit besonderer Berücksichtigung der ultrasonographischen Diagnostik.

The number of New World camelids in Germany is increasing. Owners and breeders are usually well educated regarding their animals. For practitioners, this means being up-to-date with respect to their veterinary knowledge. This includes the physiology and pathology of reproduction. Specifics of reproduction in domesticated New World camelids are an induced ovulation, the absence of cyclic sexual activity, a relatively long gestation of 336-349 days and a predominantly left-horn gestation. Ultrasonography plays an important role as part of the gynecological examination. Generally, the ultrasonographic examination can be performed transrectally and transcutaneously in the left or right flanks. Transrectal ultrasonography has to be carried out with particular caution to avoid rectal injuries. An accurate pregnancy diagnosis by transrectal scanning is possible starting from day 20 of pregnancy; using transcutaneous scanning, diagnosis is accurate starting on days 50-60 (left flank) or from day 90 (right flank) of pregnancy, respectively. Ultrasonography is also appropriate to examine the non-gravid uterus and the ovaries. Based on 5 years of experience working with farmed New World camelids, the article describes the physiology and pathology of reproduction in domesticated New World camelids. Particular consideration is given to the ultrasonographical examination of the genital organs.