Mitigating environmental externalities in livestock production through feed biotechnologies

New low phytate crop varieties have been heralded for their potential to assist animal producers manage phosphorus (P) as both an input cost and as an environmental externality. This paper investigates the economic viability of such biotechnologies under regulations that attempt to minimize fecal P pollution by limiting land application of manure. Such restrictions often require animal feeding operations to spread manure over larger areas, thus increasing cost. To assess the economics of P mitigation, the production, handling, spreading, and vegetative uptake of manure nutrients for a variety of livestock growing operations was simulated. The simulation concludes that low phytate crops can be effective at mitigating P in situations where manure spreading geography is significantly restricted. However, alternative technologies such as phytase appear to offer a lower cost mechanism for mitigating P in most situations.

► Low phytate crops and phytase can create value in feeding and manure management.
► Low phytate crops have been a comparatively high cost P management strategy.
► Phytase is often the low cost strategy to meet P limits.
► The need for P management is highly dependent on the considered system and regulations.