Extraction forces at different traction modes during manually assisted calving: An in vivo study

There are controversial recommendations regarding the approach to manually assisted calvings. Some authors prefer simultaneous trac-tion on the forelimbs of the calf, while others recommend alternating traction as the method of choice. So far only in vitro studies have been performed on this issue showing divergent results. Therefore, the aim of this study was to compare the traction forces at differ-ent extraction modes during the manual extraction of a calf in vivo. Manual calving assistance was performed on 63 Holstein-Friesian cattle from two farms in Lower Saxony, Germany. Traction was ap-plied simultaneously (SIM) to both legs, alternately (ALT) to one leg at a time or to one leg (ONE). Traction force was measured on a sin-gle limb digitally with a load cell. There was no effect of traction mode on the maximum forces applied on a single limb during the extraction of the calf (p > .05), but the passage of the thorax through the birth canal (p < .05). The maximum forces measured during ONE were higher than those measured during SIM (p < .05), while ALT did not differ from SIM and ONE (p > .05) while the thorax passes the birth canal. Therefore, traction should not be applied to only one leg to extract the thorax. Based on these results, no recommenda-tion neither for the alternate or for the simultaneous traction can be made.