Study: Dairy farmers face sleep deprivation risks during calving

DAILY Bites

• Dairy farmers averaged only 6 hours and 15 minutes of sleep per night during peak calving season, below the recommended 7–9 hours.

• Despite expectations, once-a-day milking did not significantly improve sleep duration due to additional farm tasks.

• High heart rate data indicated increased physiological stress, raising concerns about health and safety risks.

DAILY Discussion

Dairy farming is a physically demanding profession with long hours and early start times, particularly during the high-workload spring calving season. Sleep deprivation has well-documented consequences, including increased risk of accidents and negative health effects, yet little quantitative data exists on how much sleep dairy farmers actually get during peak work periods.

A study published in the Journal of Dairy Science and conducted in New Zealand sought to address this gap by measuring the sleep patterns of workers on block-calving, pasture-based dairy farms.

Researchers tracked the sleep habits of 33 workers across 10 dairy farms over a 90-day period during the spring calving season. Using the Oura Ring, a wearable sleep tracker, the study collected data on total sleep time, sleep efficiency, and heart rate variability. Participants’ work schedules, farm location, and role on the farm were also analyzed to assess their impact on sleep quantity and quality.

The study found that dairy farmers were averaging 6 hours and 15 minutes of sleep per night — well below the recommended 7 to 9 hours needed for optimal cognitive and physical functioning. As the calving period progressed and workloads increased, sleep duration decreased further. Total sleep time was closely linked to bedtime and wake time, both of which shifted earlier as the study continued.

Surprisingly, the study did not find a significant difference in sleep patterns between farmers who milked once a day versus those who milked twice a day. Despite the expectation that once-a-day farmers would start later and potentially sleep longer, farm management practices varied, and additional afternoon tasks often replaced milking time, negating any potential sleep benefits.

Sleep quality measures, such as sleep efficiency and sleep onset latency, were within normal ranges, but heart rate data suggested that farmers were experiencing significant physiological stress. Factors such as farm location and job role influenced sleep variability, with managers generally going to bed earlier than other workers.

Lead investigator Lucy Hall, Ph.D., of DairyNZ Ltd., explained, “Because dairy farmers work around machinery and large animals, sleep deprivation can have serious implications for their health and safety. These people often work in isolated situations, which only increases the risks.”

According to Hall, “Our heart rate data for participants was high compared with normal, healthy adults, indicating that farmers may be stressed over the spring calving period, although it’s not clear how much this increased stress impacts their total sleep time.”

The findings highlight the risks associated with chronic sleep deprivation among dairy farmers, particularly given their daily interaction with large animals and heavy machinery. The study suggests that improving work schedules, adjusting rosters, and increasing awareness of sleep’s importance could help mitigate some of these challenges. Further research is needed to explore sleep patterns across the entire year and to assess potential long-term health and safety implications.

Hall commented, “We hope this kind of research emphasizes that dairy farms should ensure a sufficient gap between work ending and starting again.”

Hall and the team acknowledge the study’s limitations and the need for further research. However, the findings highlight the importance of sleep for dairy farmers, as lack of rest has been linked to accidents and errors. Ensuring adequate sleep benefits both workers and farm operations.