Effective fiber continues to be a “hot” topic in balancing dairy cow rations. Shredlage, plant processing, pre-processing straw, undigested neutral detergent fiber (NDF) and total mixed ration (TMR) mixing times and order are field approaches to optimize effective fiber.
My definition of effective fiber is feed (usually forage) particles that form the forage raft in the rumen, optimize rate of feed passage and stimulate adequate cud chews. Traditional ways to measure if cows are getting adequate effective fiber include:
- More than 60% of cows at rest are chewing their cud
- Cows chew each cud or bolus 40 to 65 times before reswallowing
- Forage NDF is more than 21% of ration dry matter
- Measuring rumen pH (bolus—experimental, stomach tube samples, rumenocentesis or fistulated cow taking rumen samples)
- Comparing rumen volatile fatty acid percent via stomach tube sample or fistulated cow
- Manure scores from 2.5 to 3.5 (on a 1 to 5 scoring range)
- Normal milk fat test for the breed of cow
New technology imbedded in rumination collars allows the cow to “tell us” she has optimal rumination time and activity. The monitors “hear” rumination time or estimate the level of rumination (using an ear tag with ear motion). This technology is available to dairy farms and used by research groups to get accurate data.
These units can vary from $120 to $180 per cow unit (depending on add-on features, such as heat detection or remote cow location finding) plus software equipment to capture and evaluate data. Each cow determines her “normal” rumination time.
Dairy managers can select the level of rumination time change—such as a 30% drop from normal rumination time—to identify cows that need to be inspected. The table below illustrates the daily rumination of fresh cows. The chart is illustrating how long it takes to achieve 450 minutes of daily
rumination time (suggested as optimal value), depending on health status.
Healthy cows reach their optimal time by six to seven days after calving. If cows are slow to reach this value, your transition feeding program may need fine-tuning. Figure 1 also illustrates if fresh cows experience a metabolic challenge (displaced abomasum, ketosis or metritis in this study).
Canada researchers reported cows dropping in dry matter intake prior to calving are at higher risks to have metabolic disorders. Rumination time may allow dairy managers to measure this on their farm.
The chart at right illustrates on-farm events (heat stress or hoof trimming), cow health (mastitis or metabolic disorders) or cow status (dry cows, cow in heat or calving) can impact rumination time, which can improve management. In this data, the “normal” rumination time was 478 minutes during the lactation period.
This new technology has raised several questions that will be answered by future
research and on-farm monitoring:
1. Can rumination values be too high,
reflecting too much effective fiber and
reduced dry matter intake?
2. Which event happens first, a cow with a metabolic disorder (such as a displaced
abomasum) or reduced rumination time?
3. How quickly do I need to react to a decrease in rumination time (one day or wait for a pattern over several days)?
4. What is my action or treatment protocol once the cow changes in rumination time?
5. How much change in rumination time should I select: 20%, 30%, or 40%?
6. What is the optimal shift in rumination time that should be selected for a disease (mastitis) or metabolic disorder (which could be cow- or farm-specific) to avoid potential false positives or missing an important health or cow event?
7. If cows are moved from a pen, what is the optimal change in rumination time?
Rumination monitoring appears to be exciting technology on the dairy farm. It is critical that someone monitors and makes important management decisions using the valuable date on a daily basis.
Visit farms that are using this new technology and determine if it right for you.
Experiment on your farm to get answers to the questions listed above. Remember: Healthy rumen, healthy cow!
(Click for larger view)
This chart illustrates how long it takes to achieve the optimal 450 minutes of daily rumination time, depending on health status.