# Determining Frequency of Multiple Organ System Involvement and Concurrent Lesions Identified in Feedyard Mortalities and Potential Associations with Cattle Demographics

## TL;DR

This study found that most feedyard cattle deaths involved multiple organ systems and lesions, with the digestive and pulmonary systems most commonly affected.

## Contribution

The study is one of the first to systematically analyze the frequency of multiple organ system involvement in feedyard cattle mortalities.

## Key findings

- 72% of cattle had more than one lesion, with an average of 2.3 lesions per animal.
- Digestive and pulmonary systems were most commonly affected together, followed by cardiovascular, digestive, and pulmonary systems.
- The likelihood of multiple lesions increased with the number of days on feed (DOFs).

## Abstract

This study examined the necropsies of feedyard cattle to determine how often multiple organ systems and concurrent lesions were involved in mortalities. Researchers analyzed 889 necropsies from six feedyards in the summers of 2022 and 2023. They found that 72% of the cattle had more than one lesion, with an average of 2.3 lesions per animal. The most commonly affected systems were the digestive and pulmonary systems. The likelihood of multiple lesions increased with a greater number of days on feed. The findings suggest that recording all abnormalities during necropsies could help improve cattle health management and treatment strategies.

Necropsies are commonly used to diagnose the causes of death in feedyard cattle, but the documentation of multiple organ system involvement and concurrent lesions is limited. This observational study aimed to determine the frequency of such findings and their associations with animal demographics. Systemic necropsies were conducted for 889 cattle mortalities with minimal autolysis across six feedyards in the Central High Plains during the summers of 2022 and 2023. Lesions and abnormalities were recorded along with arrival weight, sex, days on feed (DOFs), and number of treatments. The results showed that 72% of mortalities had more than one gross lesion, averaging 2.3 lesions per animal. The most common organ systems affected together were digestive and pulmonary (19%), followed by cardiovascular, digestive, and pulmonary (6%), and cardiovascular and pulmonary (5%). Common concurrent lesions included bronchopneumonia with an interstitial pattern (BIP) and gastrointestinal lesions (GI) (8%), bronchopneumonia and GI (7%), and acute interstitial pneumonia (AIP) and GI (3%). A generalized linear mixed effects model revealed that the likelihood of multiple lesions increased with DOFs (p = 0.02). These findings highlight the value of thorough necropsy documentation to enhance our understanding of disease and guide improved feedyard management and treatment practices.