When cows in two separate milking parlors receive the same diet from the same feed center, how can one set of cows be 0.2 percent higher in butterfat than the other? That’s the question the manager of a 4,000-plus cow dairy asked one of our regional reps.
The manager had tried changing the ration, but the butterfat difference remained.
Now he wondered if the difference could be corrected, or if it was “real” and due to the days in milk and lactation number of the cows milked in the two parlors.
Fresh cows were milked at the one parlor; a higher percentage of later-lactation cows were milked at the other parlor.
The only honest answer the rep could give was “I don’t know. Let’s find out!”
First step
Shortly afterward, an analysis of the herd’s DairyComp 305 files was conducted by Dr. David Ohman, one of our tech services scientists and a milking parlor expert.
He began by evaluating whether or not backflush might be causing the low fat percentage. Through an evaluation of the milk’s freezing point, he found that the added water contributed only a minor amount to the difference between the two dairies.
Next, the records were evaluated for differences due to demographics. An extensive analysis showed that, yes, differences in fat between the two dairies could be explained by demographics. But there was more.
Dr. Ohman found it unusual that the test data fat percentage by lactation was consistently lower in one group than the other. He recommended a total mixed ration (TMR) audit to determine if feed management may be affecting butterfat levels.
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More than 400 audits have been conducted by Diamond V in recent years. Each typically follows a producer’s or nutritionist’s concern over production and/or performance levels.
Even more so, they are based on trust and respect between the regional rep, the dairy manager and the nutritionist. Trust and respect encourage a discussion of the situation and openness to having an outside expert brought in to evaluate the situation.
TMR audits, a relatively new and evolving management tool, help dairies identify and understand causes of variation in their TMRs, which should be the same day-to-day and week-to-week.
daThe audit consists of a one-day, on-farm comprehensive evaluation of feedstuffs, feedstuff preparation, ration mixing, feed delivery and consumption by the cows.
The audits also identify hazardous situations that involve TMR mixing and delivery. The eight most common hazardous situations involve vehicles backing up, high-traffic areas and blind corners, commodity bays, working around TMR mixer wagons, pits and lagoons, forage piles, dust, debris and gates.
All dairies are encouraged to develop a formal safety program and to nurture a culture of safety for employees. Good first steps are putting up safety posters, conducting a safety audit and adding a “safety talk” at all employee meetings.
TMR audit
In this case, the TMR audit began early in the morning. Before the feeders arrived, Jeff Mikus, Ph.D., a dairy technical service specialist at Diamond V, evaluated the work area for ways to be more efficient. He examined the available feeds for potential spoilage.
As TMR preparation began, Dr. Mikus evaluated the facing of the corn silage and haylage. He monitored mixing time, noted how ingredients were added and in what order. He went through a mixer wagon checklist to confirm the accuracy of the load cells and identify wear and tear on the blades and augers.
Periodically, he took feed samples along the bunk to check for consistency. As the day progressed, he monitored how the cows ate and watched for ration sorting, measured weighback levels and observed their distribution in the bunk. In addition, he noted feeding paths and feed availability after milking.
The day ended with a PowerPoint presentation to the dairy manager and nutritionist. The PowerPoint confirmed feeding strengths and provided suggestions that could be easily and quickly implemented.
Typically, these suggestions relate to management strategies that promote feeding efficiency and profitability without adding significant cost.
On this day, the TMR audit solved the puzzling production difference. It identified the culprit as forage particles that were too large. The later-lactation cows were more affected due to their lower-energy ration. Sorting by these later-lactation cows led to lower butterfat yield.
Providing a consistent diet day in and day out nurtures a consistent rumen environment. The cow’s rumen is a financial driver on the farm. If the rumen is healthy and consistent, then other bodily processes can function at optimal levels: health, reproduction and milk production.
Many factors, however, can influence TMR consistency. Yet, diets should be exactly the same no matter what pen the cow is in or where in the pen she eats.
With the culprit identified, now the dairyman and his nutritionist went to work. A two-screen Penn State Shaker Box analysis confirmed a high amount of large-particle forage in the top screen. To decrease particle size, the alfalfa hay was processed for an additional four minutes in the mixer wagon.
The results? The butterfat in the later-lactation cows increased significantly. The difference in butterfat between the two parlors now is less than 0.1 percent, essentially identical.
Other culprits
Underprocessing is one of the six most common causes of inconsistency in TMR audits. Other causes include overfilling the mixer wagon, failing to mix after adding the last ingredient, not compensating for worn mixing equipment by increasing mixing times, underprocessing poor-quality hay (which leaves clumps of hay in the ration), an ingredient mix order that could be improved and improperly adding liquids.
By developing working relationships with industry partners who have advanced training in diagnosing complex dairy management issues, dairy managers can expand their tools for solving on-farm problems. A good resource for suggestions and contacts is the professional networks of the herd nutritionist and veterinarian. PD
PHOTO: Underprocessing is one of the six most common causes of inconsistency in TMR audits. Photo by PD staff.
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Thomas Oelberg
- Field Technical Specialist
- Diamond V
- Email Thomas Oelberg
