History: Concept: Run-out tolerance by livestock sector

Confidence: Estimated — windows are field-experience-based, not published.

Canonical reference table for "why livestock can't tolerate run-out" content across pages, articles, FAQ, and dispatch training.

Run-out tolerance by sector

Sector	Run-out window	What fails first
Dairy parlour	<12 hours	Wash cycle → milk pickup refused → DFO infraction (see `reg-ontario-milk-act-propane-runout-exposure`); calf milk warming
Broiler brooding (day 1–7)	<2 hours in winter	Chick mortality from cold stress; ammoniated wet litter follows
Farrowing creep	<4 hours	Piglet pre-weaning mortality; sow stress
Turkey poult brooding	<2 hours	Same mechanism as broiler, higher temperature
Layer barn	Days, not hours	Water-line freeze; production drop
Beef finishing	Days	Office / shop heat only

Why the windows are this short

Dairy: the next milking happens on a fixed schedule (typically 2× or 3× daily), and the wash must happen before each milking. CIP needs 71–77°C start temperature (see op-dairy-parlour-propane-load-profile); without hot wash, the milk truck refuses load.
Broiler / turkey brooding: chicks and poults cannot thermoregulate at hatching — required body temperatures are met by environmental heat. A 2-hour gap in winter at a target of 32°C ambient drops to lethal cold-stress territory quickly.
Farrowing creep: piglets cannot thermoregulate in their first 48 hours. Lethargic piglets do not nurse; a heat failure cascades into pre-weaning mortality.
Layer / beef: insulating mass and adult animal heat output buffer the system. Days, not hours.

Operational implication

The variance in tolerance windows means dispatch priority cannot be uniform across livestock customers. Dairy and brooding-week broiler accounts need hour-class response; layer and beef accounts can tolerate next-day windows. Telemetry trigger settings, K-factor, and emergency rotation staffing should reflect this — see op-livestock-telemetry-keep-full-considerations and op-k-factor-livestock-vs-residential.

Sources

Field experience consolidated from SW Ontario livestock distribution practice. Published primary sources for tolerance windows do not exist — these are operational benchmarks, not research outputs.