Detection of genetic variants affecting cattle behaviour and their impact on milk production: a genome‐wide association study

Behaviour traits of cattle have been reported to affect important production traits, such as meat quality and milk performance as well as reproduction and health. Genetic predisposition is, together with environmental stimuli, undoubtedly involved in the development of behaviour phenotypes. Underlying molecular mechanisms affecting behaviour in general and behaviour and productions traits in particular still have to be studied in detail. Therefore, we performed a genome‐wide association study in an F₂ Charolais × German Holstein cross‐breed population to identify genetic variants that affect behaviour‐related traits assessed in an open‐field and novel‐object test and analysed their putative impact on milk performance. Of 37 201 tested single nucleotide polymorphism (SNPs), four showed a genome‐wide and 37 a chromosome‐wide significant association with behaviour traits assessed in both tests. Nine of the SNPs that were associated with behaviour traits likewise showed a nominal significant association with milk performance traits. On chromosomes 14 and 29, six SNPs were identified to be associated with exploratory behaviour and inactivity during the novel‐object test as well as with milk yield traits. Least squares means for behaviour and milk performance traits for these SNPs revealed that genotypes associated with higher inactivity and less exploratory behaviour promote higher milk yields. Whether these results are due to molecular mechanisms simultaneously affecting behaviour and milk performance or due to a behaviour predisposition, which causes indirect effects on milk performance by influencing individual reactivity, needs further investigation.     

The role of indoleacetaldehyde in IAA production from tryptophan by plants and by their epiphytic bacteria

Tryptophan, tryptamine, or indolepyruvic acid were applied to 2 systems: a bacterial (pea stem sections containing the epiphytic bacteria) and a plant system (pea stem sections under sterile conditions). In the plant system, the production of indoleacetic acid and indoleethanol (tryptophol) from each applied indole derivative is clearly reduced by the aldehyde reagents bisulfite and dimedon, respectively. Indoleacetaldehyde is chromatographically detected after alkaline liberation from its bisulfite addition product. In the bacterial system, the production of indoleacetic acid and indoleethanol is likewise reduced by bisulfite and dimedon. However, after tryptophan or tryptamine application, we could not detect indoleacetaldehyde in the described way. In one case only, namely tryptamine application to the bacterial system, indoleethanol production (contrary to indoleacetic acid production) is scarcely reduced by the aldehyde reagents. This indicates a bacterial pathway tryptamine → indoleethanol which bypasses indoleacetaldehyde.     

Stellungnahme zu den nomenklaturvorschlägen von E. Meijer-drees

Ohne Zusammenfassung     

Pharmacokinetics of free catecholestrogens and catecholestrogen benzoates

To provide a definite basis for studies on the biological effects of exogenously administered catecholestrogens, the time courses of the concentrations of these estrogens in serum, pituitary and CNS-tissues were studied in male rats after s.c. injection of either 150 μg of 4-hydroxyestradiol or 2-hydroxyestradiol (dissolved in 200 μl sesame oil/ethanol/ascorbic acid; 97.5/2.5/0.1; vol/vol/wt) or equimolar amounts of 4-hydroxyestradiol 3,4-dibenzoate or 2-hydroxyestradiol 2,3-dibenzoate (dissolved in 200 μl sesame oil). The injection of free catecholestrogens resulted in bolus-like elevations of the serum and tissue concentrations of the respective compound (max. values up to 9 ng/ml, half-life below 1 h) whereas the injection of catecholestrogen benzoates gave lower (max. values about 1 ng/ml) but prolonged elevations (half-life approx. 24 h and 32 h for 4-OHE₂ and 2-OHE₂) of the respective free catecholestrogen.     

Nuclei of the mammillary bodies and their fiber connections in cattle (Bos taurus var. domesticus). 2. Fiber connections of the mammillary bodies in cattle]

1. In the present information the course of fibre pathways which are connected with the mammillary body of the cattle is described in 14 series of brains (6 frontal, 4 sagittal, 4 horizontal series, stained by the combined cell-fibre-method after KLUVER and BARRERA and by the method for myelined fibres after HEIDENHAIN). 2. The mammillary body of cattle is connected with four main fibre systems. These are the fornix and the mamillary peduncle as well as the mamillo-thalamic and the mamillo-tegmental tracts. 3. The fornix system first of all represents a rich myelined fibre connection between the hippocampus and the mamillary body. But also fornix fibres entering the poor-myelined regions of the hypothalamus and the mesencephalon have been demonstrated. 4. The mamillary peduncle ascending from the mesencephalon can be traced to the lateral mamillary nucleus. 5. The mamillo-thalamic tract of cattle has its origin in the mamillary body with the mamillotegmental tract associated to a common principal mamillary tract and passes to the complex of the anterior nucleus of the thalamus, while the mamillo-tegmental tract branching off from it curves into the mesencephalon.