Assessment of the contractility of bovine lateral saphenous and digital veins in response to ergot alkaloids

Authors: Klotz, James; STOKLEY, HANNAH - University Of Kentucky; CHATTOPADHYAY, NABANITA - University Of Kentucky; HARMON, DAVID - University Of Kentucky

Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/8/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: There are a variety of computerized technologies that can contribute to conservation planning aimed at water quality improvement in agricultural watersheds. Because none of these technologies alone can identify all the options that could potentially benefit watershed outcomes and then prioritize among them, planners are left to decide what approach to take to assess watersheds and conservation alternatives. This study was conducted to illustrate how different assessment technologies can be used together in watershed planning. In the Spring Branch-Elk Creek watershed in northern Missouri, the Spreadsheet Tool for Estimating Pollutant Load (STEPL) model was used to estimate pollutant loads, aerial imagery was used to map streambank movement and riparian conditions, and the Agricultural Conservation Planning Framework (ACPF) was used to map locations where conservation practices could be placed for runoff control. Mapped results were evaluated in the field by conservation professionals. The Stream Visual Assessment Protocol (SVAP2) extended riparian mapping results, and ACPF results had >80% accuracy. Outputs contributed to a ranking scheme to prioritize practices for implementation; including ACPF-generated, by-field rankings based on distance-to-stream and slope criteria. The assessment technologies complemented each other and required resources typically available to local conservation planners. These results are of greatest interest to conservation planning professionals within and outside USDA agencies, but also to agricultural stakeholders who stand to benefit from effective watershed conservation planning processes.

Technical Abstract: Decreased blood flow caused by vasoconstriction is a hallmark of ergot alkaloid exposure. Previous research has utilized the cranial branch of the lateral saphenous vein as a model to characterize the impact of ergot alkaloids on bovine peripheral vasculature. The digital vein is more distal and closer to the hoof where damage caused by vasoconstriction occurs and may be more sensitive to ergot alkaloids. Thus, the objective was to compare contractility of the bovine lateral saphenous vein to the digital vein to increasing concentrations of ergot alkaloids. Blood vessels were collected from Holstein steers at slaughter (n=12; 551 ±29 kg), cleaned, cut into 2-mm cross-sections, and mounted in a multi-myograph. In the myograph blood vessels were submersed in continuously gassed (95% O2/5% CO2) Krebs-Henseleit buffer. Following a 1.5-hr tension equilibration, blood vessels were exposed to a reference dose of 1x10-4 M norepinephrine. Digital and lateral saphenous veins from each steer were then exposed to increasing concentrations of '-ergocryptine (ERP), ergotamine (ERT), ergocristine (ERS), ergocornine (ERO), ergonovine (ERN), tall fescue seed extract (EXT; dilutions based on measured ergovaline concentration), lysergic acid (LSA), and lysergol (LYS) were diluted to final concentrations for use in the tissue bath of 5x10-10 to 1x10-4 M. All resultant contractile response data were normalized as a percentage of the 1x10-4 M norepinephrine response and analyzed as randomized design for effects of vein and alkaloid concentration. The maximal contractile response induced by EXT, ERT, ERO, ERS, and ERP did not differ by vein type and EXT was the most vasoactive alkaloid. The response to ERN was greater for the saphenous than the digital vein (P=0.03) and LYS and LSA did not differ (P>0.05). These data confirm that the cranial branch of lateral saphenous vein is a representative model of peripheral vasculature of the bovine hindlimb.