Examination of potential methods to predict pulmonary arterial pressure score in yearling beef cattle

Susceptibility of beef cattle to high altitude disease (HAD) is of major importance to economic and genetic selection on high elevation ranches. However, currently the best indicator of HAD susceptibility is the pulmonary arterial pressure (PAP) test, a test with high cost and invasive nature. Therefore, 2 experiments were undertaken to determine whether emerging technologies that predict blood components could be used to predict the PAP score in yearling Angus cattle. In Exp. 1, 39 yearling Angus bulls were used to determine if a relationship existed between PAP score and 10 blood components provided by a hemogram using whole blood or oxygen saturation as predicted by pulse oximetry in nonanesthetized cattle measured rectally or orally. Three of the hemogram values (packed cell volume, hemoglobin concentration, and red cell distribution width) were correlated (P < 0.10) with the PAP score. Prediction equations for PAP score were generated using the hemogram values and resulted in R2 values of 0.375 and 0.305 for the regression model using all of values and the best 2-variable model, respectively. Pulse oximetry was able to provide oxygen saturation predictions rectally or orally; however, the predicted values were not correlated with the PAP score (P > 0.10) or with each other (P > 0.10). In Exp. 2, 84 yearling Angus cattle (62 bulls, 22 heifers) were used to evaluate the ability of a portable clinical analyzer to predict the PAP score using 11 blood components from a sample of whole blood evaluated at the processing chute. The portable clinical analyzer was able to provide values for all of the 11 blood components; however, none of the predicted values were correlated with the PAP score (P > 0.10). In these preliminary experiments, 3 blood component values provided via the hemogram were the only variables both correlated with the PAP score and able to contribute to the development of a useful PAP prediction equation that could reduce the cost of traditional measures of HAD susceptibility. Future research is needed to determine whether additional blood components or emerging blood analysis technologies are able to accurately predict the PAP score in beef cattle.