Novel Features of the Prenatal Horn Bud Development in Cattle (Bos taurus).

Whereas the genetic background of horn growth in cattle has been studied extensively, little is known about the morphological changes in the developing fetal horn bud. In this study we histologically analyzed the development of horn buds of bovine fetuses between ~70 and ~268 days of pregnancy and compared them with biopsies taken from the frontal skin of the same fetuses. In addition we compared the samples from the wild type (horned) fetuses with samples taken from the horn bud region of age-matched genetically hornless (polled) fetuses. In summary, the horn bud with multiple layers of vacuolated keratinocytes is histologically visible early in fetal life already at around day 70 of gestation and can be easily differentiated from the much thinner epidermis of the frontal skin. However, at the gestation day (gd) 212 the epidermis above the horn bud shows a similar morphology to the epidermis of the frontal skin and the outstanding layers of vacuolated keratinocytes have disappeared. Immature hair follicles are seen in the frontal skin at gd 115 whereas hair follicles below the horn bud are not present until gd 155. Interestingly, thick nerve bundles appear in the dermis below the horn bud at gd 115. These nerve fibers grow in size over time and are prominent shortly before birth. Prominent nerve bundles are not present in the frontal skin of wild type or in polled fetuses at any time, indicating that the horn bud is a very sensitive area. The samples from the horn bud region from polled fetuses are histologically equivalent to samples taken from the frontal skin in horned species. This is the first study that presents unique histological data on bovine prenatal horn bud differentiation at different developmental stages which creates knowledge for a better understanding of recent molecular findings.

Socio-Spatial Relationships in Dairy Cows

Farm animals may serve as models for evaluating social networks in a controlled environment. We used an automated system to track, at fine temporal and spatial resolution (once per minute, +/- 50 cm) every individual in six herds of dairy cows (Bos taurus). We then analysed the data using social network analyses. Relationships were based on non-random attachment and avoidance relationships in respect to synchronous use and distances observed in three different functional areas (activity, feeding and lying). We found that neither synchrony nor distance between cows was strongly predictable among the three functional areas. The emerging social networks were tightly knit for attachment relationships and less dense for avoidance relationships. These networks loosened up from the feeding and lying area to the activity area, and were less dense for relationships based on synchronicity than on median distance with respect to node degree, relative size of the largest cluster, density and diameter of the network. In addition, synchronicity was higher in dyads of dairy cows that had grown up together and shared their last dry period. This last effect disappeared with increasing herd size. Dairy herds can be characterized by one strongly clustered network including most of the herd members with many non-random attachment and avoidance relationships. Closely synchronous dyads were composed of cows with more intense previous contact. The automatic tracking of a large number of individuals proved promising in acquiring the data necessary for tackling social network analyses.

Comparative expression profiling of E. coli and S. aureus inoculated primary mammary gland cells sampled from cows with different genetic predispositions for somatic cell score

BACKGROUND: During the past ten years many quantitative trait loci (QTL) affecting mastitis incidence and mastitis related traits like somatic cell score (SCS) were identified in cattle. However, little is known about the molecular architecture of QTL affecting mastitis susceptibility and the underlying physiological mechanisms and genes causing mastitis susceptibility. Here, a genome-wide expression analysis was conducted to analyze molecular mechanisms of mastitis susceptibility that are affected by a specific QTL for SCS on Bos taurus autosome 18 (BTA18). Thereby, some first insights were sought into the genetically determined mechanisms of mammary gland epithelial cells influencing the course of infection. METHODS: Primary bovine mammary gland epithelial cells (pbMEC) were sampled from the udder parenchyma of cows selected for high and low mastitis susceptibility by applying a marker-assisted selection strategy considering QTL and molecular marker information of a confirmed QTL for SCS in the telomeric region of BTA18. The cells were cultured and subsequently inoculated with heat-inactivated mastitis pathogens Escherichia coli and Staphylococcus aureus, respectively. After 1, 6 and 24 h, the cells were harvested and analyzed using the microarray expression chip technology to identify differences in mRNA expression profiles attributed to genetic predisposition, inoculation and cell culture. RESULTS: Comparative analysis of co-expression profiles clearly showed a faster and stronger response after pathogen challenge in pbMEC from less susceptible animals that inherited the favorable QTL allele 'Q' than in pbMEC from more susceptible animals that inherited the unfavorable QTL allele 'q'. Furthermore, the results highlighted RELB as a functional and positional candidate gene and related non-canonical Nf-kappaB signaling as a functional mechanism affected by the QTL. However, in both groups, inoculation resulted in up-regulation of genes associated with the Ingenuity pathways 'dendritic cell maturation' and 'acute phase response signaling', whereas cell culture affected biological processes involved in 'cellular development'. CONCLUSIONS: The results indicate that the complex expression profiling of pathogen challenged pbMEC sampled from cows inheriting alternative QTL alleles is suitable to study genetically determined molecular mechanisms of mastitis susceptibility in mammary epithelial cells in vitro and to highlight the most likely functional pathways and candidate genes underlying the QTL effect.

Dual origins of dairy cattle farming - evidence from a comprehensive survey of European Y-chromosomal variation

BACKGROUND: Diversity patterns of livestock species are informative to the history of agriculture and indicate uniqueness of breeds as relevant for conservation. So far, most studies on cattle have focused on mitochondrial and autosomal DNA variation. Previous studies of Y-chromosomal variation, with limited breed panels, identified two Bos taurus (taurine) haplogroups (Y1 and Y2; both composed of several haplotypes) and one Bos indicus (indicine/zebu) haplogroup (Y3), as well as a strong phylogeographic structuring of paternal lineages. METHODOLOGY AND PRINCIPAL FINDINGS: Haplogroup data were collected for 2087 animals from 138 breeds. For 111 breeds, these were resolved further by genotyping microsatellites INRA189 (10 alleles) and BM861 (2 alleles). European cattle carry exclusively taurine haplotypes, with the zebu Y-chromosomes having appreciable frequencies in Southwest Asian populations. Y1 is predominant in northern and north-western Europe, but is also observed in several Iberian breeds, as well as in Southwest Asia. A single Y1 haplotype is predominant in north-central Europe and a single Y2 haplotype in central Europe. In contrast, we found both Y1 and Y2 haplotypes in Britain, the Nordic region and Russia, with the highest Y-chromosomal diversity seen in the Iberian Peninsula. CONCLUSIONS: We propose that the homogeneous Y1 and Y2 regions reflect founder effects associated with the development and expansion of two groups of dairy cattle, the pied or red breeds from the North Sea and Baltic coasts and the spotted, yellow or brown breeds from Switzerland, respectively. The present Y1-Y2 contrast in central Europe coincides with historic, linguistic, religious and cultural boundaries.

Analysis of key molecules of the innate immune system in mammary epithelial cells isolated from marker-assisted and conventionally selected cattle

Mastitis is the most prevalent infectious disease in dairy herds. Breeding programs considering mastitis susceptibility were adopted as approaches to improve udder health status. In recent decades, conventional selection criteria based on phenotypic characteristics such as somatic cell score in milk have been widely used to select animals. Recently, approaches to incorporate molecular information have become feasible because of the detection of quantitative trait loci (QTL) affecting mastitis resistance. The aims of the study were to explore molecular mechanisms underlying mastitis resistance and the genetic mechanisms underlying a QTL on Bos taurus chromosome 18 found to influence udder health. Primary cell cultures of mammary epithelial cells from heifers that were selected for high or low susceptibility to mastitis were established. Selection based on estimated pedigree breeding value or on the basis of marker-assisted selection using QTL information was implemented. The mRNA expression of 10 key molecules of the innate immune system was measured using quantitative real-time PCR after 1, 6, and 24 h of challenge with heat-inactivated mastitis pathogens (Escherichia coli and Staphylococcus aureus) and expression levels in the high and low susceptibility groups were compared according to selection criteria. In the marker-assisted selection groups, mRNA expression in cells isolated from less-susceptible animals was significantly elevated for toll-like receptor 2, tumor necrosis factor-alpha, IL-1beta, IL-6, IL-8, RANTES (regulated upon activation, normal t-cell expressed and secreted), complement factor C3, and lactoferrin. In the estimated pedigree breeding value groups, mRNA expression was significantly elevated only for V-rel reticuloendotheliosis viral oncogene homolog A, IL-1 beta, and RANTES. These observations provide first insights into genetically determined divergent reactions to pathogens in the bovine mammary gland and indicate that the application of QTL information could be a successful tool for the selection of animals resistant to mastitis.

Spongiform encephalopathy in a miniature zebu

The first case of spongiform encephalopathy in a zebu (Bos indicus) was identified in a zoo in Switzerland. Although histopathologic and immunohistochemical analyses of the central nervous system indicated a diagnosis of bovine spongiform encephalopathy (BSE), molecular typing showed some features different from those of BSE in cattle (B. taurus).

High-resolution sequence stratigraphic correlation in the Upper Jurassic (Kimmeridgian)–Upper Cretaceous (Cenomanian) peritidal carbonate deposits (Western Taurides, Turkey)

Upper Jurassic (Kimmeridgian)±Upper Cretaceous (Cenomanian) inner platform carbonates in the Western Taurides are composed of metre-scale upward-shallowing cyclic deposits (parasequences) and important karstic surfaces capping some of the cycles. Peritidal cycles (shallow subtidal facies capped by tidal-¯at laminites or fenestrate limestones) are regressive- and transgressive-prone (upward-deepening followed by upward-shallowing facies trends). Subtidal cycles are of two types and indicate incomplete shallowing. Submerged subtidal cycles are composed of deeper subtidal facies overlain by shallow subtidal facies. Exposed subtidal cycles consist of deeper subtidal facies overlain by shallow subtidal facies that are capped by features indicative of prolonged subaerial exposure. Subtidal facies occur characteristically in the Jurassic, while peritidal cycles are typical for the Lower Cretaceous of the region. Within the foraminiferal and dasyclad algal biostratigraphic framework, four karst breccia levels are recognized as the boundaries of major second-order cycles, introduced for the ®rst time in this study. These levels correspond to the Kimmeridgian±Portlandian boundary, mid-Early Valanginian, mid-Early Aptian and mid-Cenomanian and represent important sea level falls which affected the distribution of foraminiferal fauna and dasyclad ¯ora of the Taurus carbonate platform. Within the Kimmeridgian±Cenomanian interval 26 third-order sequences (types 1 and 2) are recognized. These sequences are the records of eustatic sea level ¯uctuations rather than the records of local tectonic events because the boundaries of the sequences representing 1±4 Ma intervals are correlative with global sea level falls. Third-order sequences and metre-scale cyclic deposits are the major units used for long-distance, high-resolution sequence stratigraphic correlation in the Western Taurides. Metre-scale cyclic deposits (parasequences) in the Cretaceous show genetical stacking patterns within third-order sequences and correspond to fourth-order sequences representing 100±200 ka. These cycles are possibly the E2 signal (126 ka) of the orbital eccentricity cycles of the Milankovitch band. The slight deviation of values, calculated for parasequences, from the mean value of eccentricity cycles can be explained by the currently imprecise geochronology established in the Cretaceous and missed sea level oscillations when the platform lay above fluctuating sea level.

Paleoglaciations in Anatolia: A Schematic Review and First Results

Anatolia is situated in the Eastern Mediterranean region between 36 – 42N and 26 – 45E. The geological records of paleoglaciations in the high terrains of Anatolia are key archives to quantify paleoclimate change in the Eastern Mediterranean area. The climate of the Eastern Mediterranean region is influenced by three main atmospheric systems: the main middle to high latitude westerlies, the mid-latitude subtropical high-pressure systems, and the monsoon climate. Glacial geological studies in Turkey have started in the late 19th century. Glacial deposits are found mainly in the eastern, northeastern and southern part of the Anatolian Peninsula. Anatolia is the fundamental element to understand the interactions between paleoenvironment, climatic variations, and development of the human societies. As the Taurus and Black Sea Mountains are sensitively situated for the paleoclimatic reconstructions, a chronostratigraphic framework on the paleoglaciation should be elaborated. The timing of the Last Glacial Maximum (LGM) in Anatolia is still unknown. Our first results from Kavron Valley (Kaçkar Mountains, NE Turkey) are encouraging for the reconstruction of paleoglaciations in Turkey and related paleoclimatological interpretations although it is presently difficult to pinpoint the classical Last Glacial Maximum – Younger Dryas – Little Ice Age moraine sequences in the field.

Bos indicus introgression into (peri-)alpine cattle breeds - evidence from the analysis of bovine whey protein variants.

The major bovine whey proteins, α-lactalbumin (α-LA) and β-lactoglobulin (β-LG), exhibit breed-specific genetic variation. The aim of this study was to identify possible new protein variants and determine the distribution of variants across a variety of 18 taurine and indicine cattle breeds applying a DNA-based sequencing approach. To this end, the open reading frames of the respective genes (LALBA and LGB) were sequenced in 476 animals. Within the LALBA gene, a previously unknown synonymous and a previously undesignated non-synonymous nucleotide exchange were identified. Furthermore, two known α-LA variants (A and B) and four known β-LG variants (A, B, C and W) were determined. The occurrence of typical indicine variants in some taurine cattle breeds, such as Suisse Eringer, German Hinterwälder and Hungarian Grey Steppe, further supports the hypothesis of ancient Bos indicus introgression into (peri-)alpine cattle breeds.