The cardiovascular effects of shechita in cattle: a systematic review shows the fallacies that vertebral artery will preserve cerebral blood flow and false aneurysms occur in severed carotid arteries.

Objective: To examine the hypotheses that (1) the Jewish practice of animal slaughter called shechita leaves meaningful cerebral blood flow through the vertebral arteries in cattle and (2) false aneurysms occur in carotid arteries that impair blood loss from hemorrhaging.

Methods: A systematic literature review and calculations from existing data.

Results: The shechita ventral-neck incision produces an immediate cessation of blood flow through the carotid arterial system, a dramatic fall in systemic arterial blood pressure (BP), and a more rapid fall in vertebral BP. Calculated cerebral blood flow is < 5% of normal within 10 seconds, a level that likely cannot sustain brain function or viability, a finding consistent with evidence that ligation of the vertebral arteries prior to ventral-neck incision does not alter brain function. None of the published histologic data are consistent with the definition of a false aneurysm. Data suggest the presence of fibrin or parts of blood clots inside or a hematoma around the severed carotid artery. None show significant intravascular thrombosis. There are no experimental data linking a false aneurysm with blood loss.

Conclusions: Shechita produces a rapid fall in BP that reduces cerebral blood flow to < 5% within a few seconds, demonstrating the inadequacy of vertebral circulation to maintain cerebral blood flow. The label of false aneurysm is a misnomer, and the data do not convincingly link it to blood loss.

Clinical relevance: Clinicians should not be concerned that shechita in cattle will leave meaningful cerebral blood flow through vertebral arteries.