Extraction forces in bovine obstetrics: an in vitro study investigating alternate and simultaneous traction modes
| Autor: | C. Heun, Hermann Seifert, Matthias Lüpke, F. Goblet, Heiner Bollwein, M. Becker, Georgios Tsousis |
|---|---|
| Přispěvatelé: | University of Zurich, Becker, M |
| Rok vydání: | 2009 |
| Předmět: |
Male
medicine.medical_treatment In Vitro Techniques Models Biological In vitro model Physical Phenomena Food Animals Pregnancy Birth Injuries medicine In vitro study Animals Small Animals Pelvis Tractive force 630 Agriculture Equine Skull Extraction Obstetrical Extremities Anatomy Traction (orthopedics) body regions 10187 Department of Farm Animals medicine.anatomical_structure Animals Newborn 3404 Small Animals 570 Life sciences biology Animal Science and Zoology Cattle Female 1103 Animal Science and Zoology 3403 Food Animals 3402 Equine |
| Zdroj: | Theriogenology. 73(8) |
| ISSN: | 1879-3231 |
| Popis: | Whether extraction of a calf in longitudinal anterior presentation should be carried out by simultaneous or alternate traction on the forelimbs remains controversial. Because most recommendations are based on empirical observations rather than on scientific studies, the aim of this study was to develop an in vitro model to objectively compare the forces occurring during alternate and simultaneous traction. In a biomechanical in vitro model, 12 dead Holstein-Friesian (Bos taurus) calves were pulled through the prepared pelvic specimen of a cow at a controlled speed using two electric motors. Traction was applied simultaneously (ST) to both legs or alternately (AT) to one leg at a time to advance the calf 5 cm (AT 5) or 10 cm (AT 10). Forces on each limb were measured digitally using load cells. In all cases, two peaks of maximum force occurred during the extraction of the cranial part of the body. The first peak was observed when the elbows were pulled into the pelvis, and the second peak occurred when the chest emerged from the pelvis. Up to and including entry of the elbows into the pelvis, the maximum force on a single limb (341+/-106 N) was lowest (P0.01) using AT10. The maximum traction forces acting on a single limb using AT5 (411+/-86 N) and ST (431+/-127 N) did not differ (P0.05). During extraction of the thorax, the maximum force acting on a single limb was lower (P0.0001) using ST (352+/-98 N) compared with AT5 (432+/-79 N) and AT10 (547+/-115 N). Based on these findings, alternate-limb traction, 10 cm at a time, should be used until both elbows have entered the pelvis. Simultaneous traction should then be applied to both forelimbs to complete extraction of the chest. |
| Databáze: | OpenAIRE |
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