For dairy nutritionists and dairy managers, it’s frustrating to learn that the ration delivered to cows is not always the ration that was formulated. A diet can’t do its job when it’s not correctly mixed, delivered or managed.
Or it can’t do its job when it includes feed ingredients that are inconsistent in composition or nutrient value.
Even more challenging is the investigative process to uncover these changes because there are so many variables in dairy management that affect cow performance – nutrition being just one of those components.
Monitoring rumination data is an excellent place to begin an inquiry whenever there’s a question of performance consistency. Rumination is positively related to feeding time, it facilitates digestion, particle size reduction and subsequent passage from the rumen, thereby influencing dry matter intake.
Rumination also stimulates salivary secretion and improves ruminal function via buffering.
All of these factors directly influence cow health, performance and productivity. As a result, rumination data provides the means to find the root of an issue and enable dairies to take corrective action.
Is it the ration or not?
For example, a Midwest dairy recently probed a troubling change in the rumination pattern for one of its high-group pens.
Instead of steady rumination levels in which pen rumination only fluctuated by about 10 to 15 minutes, cows in the pen experienced rumination swings of 50 to 60 minutes or more, particularly for several hours after the cows returned from the parlor.
Furthermore, there were significant differences in rumination for this pen versus other groups of cows on the dairy.
On the plus side, the dairy’s rumination monitoring program was able to track these data in real time throughout the day, so they were not tracking averages, which can mask within-day variation and take longer to find the source of challenges.
The dairy manager and herd nutritionist walked through the barn to see whether there were any visual clues as to what was behind the changes in rumination.
This step didn’t reveal any obvious visual problems, but milk component levels were two points lower than the other high-group pen when they reviewed group performance data captured by the dairy’s herd management program.
A feed analysis indicated that the nutritionist was using accurate nutrient levels for feed ingredients in the ration. In addition, the number of cows on the health list for this pen had increased by 25 percent in recent weeks.
Variability issues
Keep in mind that any time there is a planned change in ration ingredients, feeding activities, cow routine or grouping strategies, rumination patterns vary. You can see corresponding changes in the data when these management actions occur.
Concerns arise when these dips become deeper than anticipated, last longer than a day without returning to normal levels or happen unexpectedly, such as when no planned changes in ration ingredients have occurred – as was the case on this dairy.
If rumination is chronically depressed by 10 to 20 percent due to management, then it’s reasonable to predict compromised ruminal function and greater risk for associated problems such as subacute rumen acidosis, poorer digestive efficiency, lameness, and lower milkfat and protein output.
The dairy returned to rumination data for answers since rumination is highly sensitive to changes in dietary physically effective neutral detergent fiber and fiber digestibility. These factors are affected by forage and ration management as well as variations in feed mixing and delivery.
And the factors influence cow health, such as with increased digestive upsets as well as decreased milk component production.
Cause and effect
Once the data were gathered, the dairy assessed key areas including standard operating procedure compliance, facility limitations and management routines. Often, changes in rumination measured on-farm reflect changes in feed or feeding management, cow grouping or cow movement, and overall cow comfort.
To begin, the dairy manager encouraged feeders to push up feed more often. This action helped reduce rumination variation a bit – but didn’t solve the problem.
Further evaluation found that due to a change in feeding team personnel, feed for this pen was mixed longer than for the other pen, negatively affecting the physical properties of the ration. Not surprisingly, particle size was not optimal nor were neutral detergent fiber levels.
Also, due to physical restraints on the dairy, the pen had become more overcrowded than in the past. The cows were not able to eat, then rest and ruminate as long as they had in the past. This meant cows were forced to change their desired behavior.
In addition, since there was not enough room at the bunk, the ration was sorted by the time the later-feeding cows made it to the bunk. Therefore, the ration they consumed was of lower quality than intended.
Once these facts were discovered, the cows’ rumination and performance responses made perfect sense.
According to researchers, cows that are forced to delay their feeding time due to overcrowding may consume a poorer-quality diet, and these cows may be unable to maintain adequate nutrient intake to maintain high levels of milk production.
Furthermore, when cows do not have access to feed when they want to eat, they may overeat following a period of feed deprivation. Increased feeding competition due to overstocking may reduce intake and increase feeding rate, possibly increasing the risk for metabolic problems such as displaced abomasum and subacute ruminal acidosis.
Additional research reveals that when pens are overstocked by 30 percent in a four-row barn, the number of cows ruminating at any given time drops by 10 percentage points. A two-hour difference in rumination time per day results in 9.4 gallons of saliva production – enough buffering capacity for an entire day.
The solution
As a long-term resolution, the dairy retrained feeding personnel about proper feed mixing and feed delivery procedures, using the rumination data to demonstrate what happens to the cow when protocols are not observed. The training has been scheduled on a regular basis to help prevent procedural drift, as well.
Next, the dairy adjusted its grouping strategy to better distribute animals and prevent overcrowding extremes. It is also exploring the expansion of facilities as a possible way to prevent a return of the overcrowding issue.
Finally, dairy managers and the farm’s nutritionist renewed efforts to reduce nutritional variation wherever possible. The lessons from this troubleshooting experience underscored the constructive role real-time rumination monitoring plays in the dairy’s management. 
References omitted but are available upon request. Click here to email an editor.
Brandt Kreuscher is a dairy business manager with Allflex USA and SCR Dairy. Email Brandt Kreuscher.
