Rumination sensors in a grazing system
Dairy cattle and dairy farms have become part of the emerging world of precision technology. Routinely, dairy farmers are often tipped off to trouble in the herd when they see a drop in milk production. The drop could have been caused by a change in feed quality, reproductive status, sickness, or a variety of other conditions.
Now, however, with the use of precision dairy technology, we are able to track feeding behavior, activity levels, temperature and health status of cattle with the expectation of better understanding behavior and overall health. At the West Central Research and Outreach Center (WCROC) in Morris, MN, we installed Heatime® LD-HR Tags from SCR Dairy in our organic and conventional dairy herd. We have tags for all 230 of our lactating dairy cows. We are observing activity and rumination of cows on pasture and in winter housing systems to evaluate fertility and health of grazing cattle.
This system allows us to monitor rumination (chewing) in addition to activity levels of cows. The tags allow us to "listen" to our cows 24 hours a day, even in the middle of the night when nobody is around. Our tags are the "HR" style, meaning they measure both rumination and activity, giving extra confirmation that cows may be sick or in heat. Like many other activity monitors, ours use an accelerometer to gauge our cows' daily movement. Unique to the HR Tag, we are also able to monitor rumination through a microphone installed around the neck. This microphone is actually picking up jaw movements as bones rub together during rumination. Rumination is measured in minutes of rumination per day. So far, we've gathered over one million data points.
Activity and rumination are typically observed in two hour time blocks. In our dairy herd, activity and rumination patterns mirror each other; at night, the activity is low and rumination is high and vice versa during the day. Activity is highest in the evening (4:00-8:00pm), which is mainly because the cows are walking to and from the milking parlor. On average, our cows are ruminating 490 minutes per day, which is typical of most dairy cows.
The graph below has rumination (minutes/day) for each of the conventional and organic dairy herd at the WCROC from May 2014 to January 2015. Rumination for the conventional herd remained fairly constant across the 7 months because of ration and housing consistencies. However, the organic grazing herd rumination fluctuates by month. Rumination went down during June and July because cows were walking more to the pasture to eat fresh grass. Later in the year rumination was higher for the organic herd because of the higher forage diet compared to the conventional herd. Rumination climbed in September as cows started to be supplemented with a TMR because of the decreased productivity of the pastures.
In the future, we will be evaluating other activity and rumination systems for cows, and hope to provide valuable information to dairy producers that install these activity and rumination monitoring systems. Please mark your calendars for the 2015 Precision Dairy Conference and Expo at the Mayo Civic Center, in Rochester, Minnesota. The dates are June 24-25, 2015. For more information, please visit the Precision Dairy Conference and Expo website. The program will include various dairy producer panels, many industry updates, and three plenary talks that will summarize practical precision dairy management information.