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Extraction forces in bovine obstetrics: an in vitro study investigating alternate and simultaneous traction modes


Becker, M; Tsousis, G; Lüpke, M; Goblet, F; Heun, C; Seifert, H; Bollwein, Heiner (2010). Extraction forces in bovine obstetrics: an in vitro study investigating alternate and simultaneous traction modes. Theriogenology, 73(8):1044-1050.

Abstract

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 (P<0.01) using AT10. The maximum traction forces acting on a single limb using AT5 (411+/-86 N) and ST (431+/-127 N) did not differ (P>0.05). During extraction of the thorax, the maximum force acting on a single limb was lower (P<0.0001) 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.

Abstract

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 (P<0.01) using AT10. The maximum traction forces acting on a single limb using AT5 (411+/-86 N) and ST (431+/-127 N) did not differ (P>0.05). During extraction of the thorax, the maximum force acting on a single limb was lower (P<0.0001) 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.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Veterinary Clinic > Department of Farm Animals
Dewey Decimal Classification:570 Life sciences; biology
630 Agriculture
Scopus Subject Areas:Health Sciences > Small Animals
Health Sciences > Food Animals
Life Sciences > Animal Science and Zoology
Health Sciences > Equine
Language:English
Date:2010
Deposited On:03 May 2018 08:21
Last Modified:31 Jul 2020 01:48
Publisher:Elsevier
ISSN:0093-691X
OA Status:Closed
Publisher DOI:https://doi.org/10.1016/j.theriogenology.2009.11.031
PubMed ID:20116838

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