Nutritional and management considerations in beef cattle experiencing stress-induced inflammation

Abstract Text: When transported to feedlots, beef cattle are exposed to several stressors within a short period of time that directly impact their performance and welfare. The main stressors associated with this “feedlot transfer phase” (FTP) – weaning, road transport, and feedlot entry - increased (P < 0.05) plasma concentrations of cortisol, pro-inflammatory cytokines, and acute-phase proteins (APP), while the magnitude of this response was negatively correlated (r = -0.50, P < 0.01) with feedlot receiving ADG and DMI. Further, feed and water deprivation elicited (P < 0.01) an APP response and reduced (P < 0.03) receiving performance similarly as in cattle transported for long distances. Hence, strategies to alleviate the APP response elicited during the FTP were evaluated: 1) Steers were assigned to continuous road transport for 1,300 km (TRANS), or road transport for 1,300 km with rest stops every 430 km (STOP). During feedlot receiving, ADG and G:F were similar (P > 0.68) between TRANS and STOP. Plasma concentrations of APP were greater (P ≤ 0.04) in TRANS compared to STOP on d 1 of receiving. 2) Steers transported for 1,300 km received (SUP) or not (CON) Ca soaps of soybean oil during a 28-d preconditioning. Upon transport, plasma TNF-α increased for CON but decreased for SUP steers (P < 0.01). Steers assigned to SUP had greater (P = 0.02) ADG compared with CON steers during the receiving phase. Upon slaughter, carcass yield grade and marbling were greater (P < 0.05) for SUP compared with CON. A subsequent trial evaluated the inclusion of camelina meal in similar research design. During feedlot receiving, SUP steers had reduced (P < 0.01) plasma APP concentrations and tended (P = 0.10) to have greater G:F compared to CON. 3) Steers were transported for 1,300 km and administered flunixin meglumine (1.1 mg/kg BW) at truck loading and unloading, or meloxicam (1 mg/kg of BW) at loading and during the initial 7 d of feedlot receiving. Both anti-inflammatory drugs reduced (P < 0.05) the APP response elicited during the FTP compared with non-treated cohorts, but only meloxicam increased (P < 0.04) receiving ADG and G:F. In summary, inclusion of rest-stops during transport, preconditioning PUFA supplementation, and use of anti-inflammatory drugs are alternatives to alleviate the APP response elicited during the FTP, whereas PUFA and meloxicam administration enhanced feedlot performance of feeder cattle.

Keywords: beef cattle, inflammation, mangement, nutrition