Browsing by Author "Schuler, Gerhard"

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The Elecsys AMH Assay Is a Suitable Method to Detect Gonadal Tissue in Male Alpacas and Llamas
(Wiley, 2025) Sendag, Sait; Wagner, Henrik; Turgut, Ali Osman; Koca, Davut; Schuler, Gerhard; Wehrend, Axel
Objective: Anti-Mullerian hormone (AMH) has become an important hormonal parameter for the detection of gonadal tissue and for the diagnosis of gonadal functions and pathologies. To our knowledge, there is currently no homologous test for AMH measurements in South American camelids (SACs). Therefore, the objective of the present study was to determine serum AMH concentrations in postpubertal male alpacas and, for the first time, in llamas, using the Elecsys AMH assay kit that has not previously been tested in these species. To obtain indications of the specificity of this method in SAC, measurements were carried out in male gelding in which concentrations below the detection limit were to be expected. Methods: In this context, 37 blood samples collected by jugular venipuncture from 21 alpacas and 16 llamas were used. The obtained blood was centrifuged at 3000 g for 20 min, and the serum was stored in Eppendorf tubes at -20 degrees C until AMH concentrations were measurement. The measurement of AMH levels was conducted in a commercial diagnostic laboratory (Laboklin, Bad Kissingen, Germany) using the electrochemiluminescence immunoassay kit Elecsys AMH run on the fully automated Cobas e 601 analyser (Roche Diagnostics Deutschland GmbH, Mannheim). The AMH test had a minimum detection limit of 0.01 ng/mL and a maximum detection limit of 23 ng/mL. The intra-assay coefficient of variation is between 2.7% and 3.3%. Results: Blood serum AMH levels ranged between 4.10 and 22 ng/mL (median: 9.80 ng/mL) and 1.79 and 10.05 ng/mL (median: 4.00) in intact alpacas (age: 6.30 +/- 2.71 years; n = 10) and llamas (age: 5.50 +/- 4.34; n = 8), respectively, and were significantly different between samples obtained from the two species (p < 0.05). Correlation analyses regarding an age dependence of AMH concentrations yielded negative correlation coefficients for both species but non-significant p values (alpaca: r = -0.165, p = 0.649; llama: r = -0.547, p = 0.160). In alpaca (n = 11) and llama geldings (n = 8), blood serum AMH levels were below 0.01 ng/mL (p < 0.001). These results prove that the antibodies used in the Elecsys AMH assay significantly and specifically cross-react with SAC AMH. Conclusions: In gelding llamas and alpacas, AMH concentrations were below the limit of detection (<0.01 ng/mL), which was significantly lower compared to intact animals (p < 0.001). The Elecsys AMH assay is therefore considered a suitable method for detecting gonadal tissue in SAC.
Oestrogen and Progesterone Concentrations in Intrapartum Cows With Insufficient Cervix Dilation
(Wiley, 2024) Sendag, Sait; Koca, Davut; Arslan, Talha; Schuler, Gerhard; Wehrend, Axel
The cervix is an important organ that has to dilate sufficiently at delivery to allow the foetus to transition to extrauterine life. Insufficient dilatation of the cervix (IDC) is a frequent cause of dystocia in cattle. The mechanisms underlying cervical opening and the pathogenesis of IDC are still widely unclear. Systematic studies on the relationship between IDC and steroid hormones have been limited and have yielded inconsistent findings. This study aimed to measure oestrogen and progesterone (P4) concentrations in intrapartum cows presented with dystocia due to IDC and in a comparison (C) group of cows with eutocic delivery. Before any obstetrical procedures, and right after the initial evaluation, blood samples were taken from IDC and C animals. Concentrations of P4, oestradiol-17 beta (E2), free total oestrogens (FTE) and conjugated total oestrogens (CTE) were measured by established radioimmunoassays. Concentrations of P4 (p = .538), FTE (p = .065) and CTE (p = .605) were not statistically different between C and IDC groups. However, E2 levels in group C were significantly lower when compared to those in the IDC group (p = .013), which is inconsistent with the function of oestrogens in cervical dilatation. The correlation analysis demonstrated significant positive correlations between the pairs P4 versus FTE, P4 versus E2 and FTE versus E2 in group C and between the pair FTE versus E2 in group IDC. In conclusion, the results suggest that local activities of steroids relevant to the aetiology of IDC are not reflected by concentrations in the systemic circulation or that other factors are clearly more important.