Evaluating human injury risk during interactions with unhealthy Holstein cows.

In the United States, the dairy industry has a greater-than-average injury rate on farms. Most injuries are caused by cattle during interactions with dairy workers. Researchers have shown that cow behavior is altered when a cow is unhealthy; however, no studies examined whether these altered behaviors are exhibited during human-cow interactions and how they may pose a risk to workers. The purpose of this study was to evaluate how the health status of dairy cows impacts the safety risk for dairy workers during human-dairy cow interactions. This study was conducted at Washington State University’s Knott Dairy Center in Pullman, WA. Data were collected during Fall 2023 and Winter 2024. Lactating, multiparous Holstein cows (n = 58) were enrolled in the study. Cow health status was determined using CowManager, an electronic ear tag that records activity and ear temperature and uses a proprietary algorithm to alert producers to sick cows. Unhealthy cows (n = 29) enrolled in the study were those whose health status was labelled as ‘suspicious’ by CowManager. A healthy counterpart, not labelled unhealthy but matched with a similar lactation number, reproductive status, and days in milk, was selected for each unhealthy cow. Two Brinno time-lapse video cameras were installed in the holding pen area, and video footage was continuously recorded during morning milkings. Enrolled cows and milkers were fitted with Polar H10 heart rate monitors, and heart rate data were collected while cows and milkers were in the holding pens. Video footage was observed, and behaviors were recorded according to an ethogram. The ethogram included cow behaviors and human behaviors related to low-risk or high-risk potential for human injury. Data were analyzed in SAS (SAS 9.4) using PROC GENMOD, PROC MIXED, and PROC CORR. Unhealthy cows tended to spend a greater percentage of time in the holding pen without a milker present (88 ± 4%) than healthy cows (75 ± 6%, P = 0.09), and milkers spent a greater percentage of their time engaging in high-force tactile (such as pushing) interactions with healthy cows (12 ± 4%) than with unhealthy cows (2 ± 1%, P = 0.08). These results indicate that there are possible risk level differences in interactions with healthy versus unhealthy dairy cows. This information will be used to educate dairy farm employees about these risk differences, with the intention of reducing the number of human injuries caused by interactions with unhealthy dairy cows. [ABSTRACT FROM AUTHOR]