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0408 PD: From the start to the finish: Manage the transition period

Elliot Block Published on 27 February 2008

Can you imagine running a marathon without proper training? The 26-mile trek from start gate to finish line would be challenging without proper conditioning, diet and preparation. Now, think of the 305-day lactation dairy cow’s experience.

They, much like a runner, need the right nutrition, condition and preparation to complete a successful lactation.And you, like a trainer, can prepare your herd with proper nutrition and environment for a successful lactation.

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According to Dr. Michael Overton of the University of Georgia’s College of Veterinary Medicine, the transition period is the foundation for the entire lactation. Without a good start, cows may not produce to their full potential and are at risk for metabolic disorders and premature culling.

Overton notes that in many herds, about 30 percent of all culled cows leave the herd within the first 60 days of lactation. In other words, about 10 percent of all cows calving leave the herd in the first two months following calving. Either way you look at it, these statistics are troublesome. Refocusing our attention on transition management is the key to reducing this problem.

Three weeks before
Producers often spend time focusing on fresh cows as they enter the milking string, but guaranteeing their success starts long before calving. The three-week period before calving has a direct effect on dry matter intake (DMI), peak milk production and incidence of costly metabolic disorders once cows reach the milking string.

The most important area to focus on in the prefresh pen is DMI, says Overton. Because feed intake during the close-up period has a direct impact on postpartum production and health, maintaining DMI, or alternatively, minimizing the inevitable drop in feed intake, is essential.

One proven way to maintain DMI is to focus on balancing dietary cation anion difference (DCAD). A negative DCAD is important to prefresh cows because it helps to maintain the necessary blood levels of calcium by increasing cows’ ability to mobilize calcium from bones and improving overall efficiency of calcium absorption and utilization in the body. The end result is higher and more stable blood calcium levels, which are necessary for cows to avoid the common pitfall of milk fever and low blood calcium (subclinical hypocalcemia), while maintaining DMI. Seen especially in older cows, both clinical and subclinical milk fever can have dramatic impacts on DMI, peak milk production and the prevalence of other metabolic problems. Research has shown that lowering DCAD in the close-up group to between -8 to -12 milliequivalent per 100 grams ration dry matter can facilitate optimal DMI while reducing the risk of metabolic disorders.

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Overton mentions that formulating prefresh rations for proper DCAD is only half the battle – monitoring DCAD is just as important. In the herds he works with, Overton tests the urine pH of eight to 10 cows that have been on the close-up ration for at least 48 to 72 hours. This representative sample provides the herdsman with enough data to know how cows are responding and if adjustments need to be made. While the ideal urine pH for large-framed dairy breeds is 6.4 to 6.8 and small-framed dairy breeds’ ideal pH levels fall between 6.0 and 6.5, Overton tries to ensure that all cows being tested fall within the 6.0 to 6.9 range.

Three weeks after
Once cows enter the milking string, the job of dairy producers seems quite simple: Increase DMI by avoiding obstacles that cause cows to reduce intake. But achieving this goal requires astute management by dairy producers, herdsmen and feeders to ensure fresh cows receive exactly what they need and that obstacles that might impede feed intake are removed.

Because this group is going through so many changes, it’s not uncommon to see them respond by eating less. As a producer, providing fresh cows with the right blend of quality feedstuffs is crucial to increase DMI. Overton mentions that, if provided the proper nutrition in the close-up pen, fresh cows should be able to calve and start eating the normal high-cow ration in herds with a one-group feeding approach.

Alternatively, the normal high-cow diet can be modified by increasing metabolizable protein while slightly reducing the fermentable carbohydrate load. In either case, the point is to provide adequate fiber and to provide sufficient nutrients to allow cows to reach their peak production and early lactation potential.

The right blend of metabolizable protein (amino acids) and carbohydrates (starch, sugars and fermentable fiber) is critical for fresh cows. While all cows will spend some time after freshening in negative energy balance, the sooner cows can reach a positive energy balance, the better the lactation will be. A positive energy balance is needed not only for optimum peak milk production but improved reproductive performance, too. Unfortunately, due to poor transition cow management, many farms feel they must feed low-energy rations just to avoid early lactation displaced abomasums (DA). This approach, combined with low DMI, often leads to prolonged and more severe negative energy balance issues.

Just as negative DCAD was important in the prefresh pen, positive DCAD is necessary after calving for optimal DMI and milk production. Potassium and magnesium, Overton notes, are two very important macrominerals for fresh cows.

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Research done in Texas found a direct link between milk production and the amount of potassium in the cows’ diets. Since 13 percent of the potassium in a cow’s body is used for milk, high-producing cows can be potassium-deficient as more potassium is pulled to the milk and levels are lowered in the blood.

By utilizing a high-quality source of feed-grade potassium carbonate, you can provide a safe and effective source of the potassium necessary for raising DCAD levels. A DCAD level of +35 to +45 milliequivalent per 100 grams of ration dry matter encourages high levels of DMI while providing a healthy rumen environment. Care should be taken to ensure adequate levels of magnesium are fed when cows are fed these higher potassium levels. Be cautious of feeding another common commodity, potassium chloride – the chloride is a negative anion and can countereffect the positive cation, potassium.

Overton notes that although nutrition plays a large role in transition cow health, poor management practices can cause significant transition problems as well. Focus on the following areas to ensure cows reach positive energy balance quickly and are conditioned for high production, good reproductive performance and free of metabolic disorders.

Feedbunk space. It’s often recommended that cows have 24 inches of usable bunk space to encourage optimal DMI. In the close-up and fresh cow pens, Overton recommends providing 30 to 36 inches. This can be done by lowering the stocking density to 85 to 90 percent so cows have the extra space they need, which will encourage higher DMI.

Standing time. Locking up fresh cows for long periods of time can have a negative impact on energy balance, lameness and overall cow comfort. Make sure fresh cows have ample time to perform their daily routine by keeping them locked up a maximum of 30 minutes to an hour each day.

Pen changes. Especially right after calving, moving cows from one pen to another can impact performance. Keeping cows in a consistent environment can make the adjustment to the milking string smoother.

• Grouping. If possible, group first- lactation animals separately. This can help encourage DMI in heifers that may otherwise be timid around older cows in the herd, says Overton. No matter if you’re feeding first-calf heifers or fifth-lactation cows, focusing on the transition period – the three weeks prepartum and three weeks postpartum – can help you prepare your herd for a successful and profitable lactation. By providing the right ration and right environment, you can ensure your cows will reach – and stay – in the milking string from the starting gate to the finishing line. PD

References omitted but are available upon request at

Elliot Block for Progressive Dairyman

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