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0507 PD: Close-up feeding programs reduce health expense

Elliot Block Published on 09 May 2007

Health problems in early lactation are costly and frustrating but, thankfully, mostly avoidable with proper close-up feeding programs. The time surrounding calving has a huge impact on a dairy’s profitability because of the health problems that can diminish productivity. Improving management and nutrition of transition cows is time well spent.

The transition period – three weeks before and three weeks after calving – is when the cow’s immune system is functionally suppressed, making her more vulnerable to illness. Numerous studies show that immunosuppression contributes to higher incidence of infectious disease and metabolic disorders.

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Impaired immunity during transition contributes to new infections such as mastitis and retained placenta, among others. Reduced immunity also can cause cows silently carrying pathogenic bacteria such as Johne’s disease or salmonellosis to break out with clinical disease within a short time after calving.

Research from a past USDA National Animal Health and Monitoring System (NAHMS) study showed that 8 to 10 percent of all lactations begin with clinical hypocalcemia, more commonly known as milk fever. Cows with clinical signs of milk fever will have a hard time standing, little or no appetite, a dry nose, a low body temperature and cold ears.

Cows starting their lactations with milk fever will produce 14 percent less milk during lactation, according to Dr. Robert Corbett, DVM. As an independent nutritionist with Dairy Health based in Spring City, Utah, Corbett consults dairy clients throughout the West.

A study of more than 2,000 cows showed a cow suffering from milk fever is eight times more likely to develop mastitis, and she is 24 more times more likely to develop ketosis, a metabolic disorder that occurs in early lactation when feed intake is not sufficient to provide enough energy to meet the needs of high-producing cows.

Dairy producers often assume fresh cows that don’t show signs of milk fever have normal calcium levels in blood, explains Corbett. Yet a high percentage may be suffering from subclinical hypocalcemia, a metabolic disorder that occurs when blood calcium is below normal, but not low enough for the cow to exhibit visible signs of milk fever. More than 50 percent of cows in their second lactation, and more than 25 percent of heifers, experience subclinical hypocalcemia after calving, according to a recent USDA-NAHMS study.

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Subclinical hypocalcemia can result in a myriad of health problems, Corbett says. Since adequate calcium levels are necessary for all muscle contractions, hypocalcemia can mean decreased appetite and feed consumption, negative energy balance in early lactation, excessive weight loss and ultimately a greater incidence of displaced abomasums and lower peak milk levels. Reproductively, subclinical hypocalcemia can lead to a higher incidence of retained placentas and uterine infections, resulting in delayed breeding and poor pregnancy rates.

Researchers also believe that a hypocalcemic cow could have decreased muscle tone in the smooth muscle that makes up the teat sphincter. This loss of muscle tone could cause the teat canal to remain partially open, exposing the mammary gland to mastitis-causing bacteria. This is a plausible explanation of why higher mastitis incidence occurs around the time of freshening.

Besides calcium’s critical role in a cow’s muscle function, it also plays an essential role in proper immune cell function. So maintenance of proper blood calcium levels is critical for an animal’s health.

Feeding to avoid metabolic disorders

Corbett points out that studies show well-formulated close-up dry cow rations with a negative DCAD (dietary cation-anion difference) can significantly reduce the incidence of both clinical and subclinical hypocalcemia in fresh and early lactation cows. DCAD measures the difference between positively-charged potassium and sodium cations and negatively-charged chloride and sulfur anions.

A negative DCAD makes the blood slightly acidic, stimulating the process of calcium resorption (release) from the bones. A urine test will indicate if blood pH is at an appropriate level. Ideal urinary pH levels in non-Jersey cows should be around 6.5. Jersey cows can go lower, to around 6.0.

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Following a negative DCAD feeding plan results in:

•Increased dry matter intake (DMI) in early lactation

•Increased milk production

•Decreased incidence of metabolic disorders

•Decreased retained placentas and uterine infections

•Fewer displaced abomasums

•Decreased udder edema in first-calf heifers

•Improved reproductive performance

Cows need two to three weeks on a close-up ration

It is important close-up rations have the same type of feed ingredients as fresh cow rations, Corbett says. This allows rumen microorganisms to adapt prior to calving – a process that may take two to three weeks, he explains – and be accustomed to feed ingredients in the lactating diet.

The majority of lactating cow rations contain at least some alfalfa, which is high in potassium. Feeding high potassium forages in pre-calving diets can create severe problems with hypocalcemia. Commercial products high in chloride allow nutrition consultants to formulate negative DCAD rations, even when the ration contains forages high in potassium, such as alfalfa hay, Corbett says.

The transition-specific rumen fermentation enhancer makes it possible to feed some of the same feeds in lactating diets to close-up cows. This makes the transition from the close-up ration to the lactating ration much smoother, Corbett believes. Close-up rations must be well-balanced for energy and protein density, as well as DCAD. Corbett also believes getting maximum DMI into cows is absolutely essential.

A study Dr. Corbett conducted found that cows on a well-balanced close-up ration yielded 1,000 pounds more milk for every additional week they spent in the close-up pen. He summarized records from more than 13,000 cows and first-calf heifers on five dairies to determine production differences.

Corbett evaluated the production differences for cows calving in a period of significant heat stress during peak milk production versus cows not experiencing heat stress. Regardless of the season, about an additional 2,000 pounds of milk per lactation was produced when cows received a close-up ration for 15 to 21 days versus one to seven days. The increase in production most likely was a result of DMI increases of 2 to 4 pounds per cow per day and a reduction in metabolic disorders.

Avoiding health problems yields profits

Each case of milk fever equates to $186 in lost profit or $13 per cow per year for every 100 cows. An independent research study showed feeding a transition-specific rumen fermentation enhancer for 21 days prior to calving reduced milk fevers from an average 7 percent incidence to just 2 percent. That saves $9.30 per cow on every 100 cows due to lower health costs, and equates to additional profits of $5.10 per cow per year.

Corbett’s research also shows how a negative DCAD cuts the typical 15 percent retained placenta rate nearly in half. With each case of retained placenta costing an average of $217, or $32.55 per lactation for every 100 cows, reducing the incidence to just 8 percent yields an additional $15.19 profit per cow per year.

The effect of a negative DCAD carries through to subsequent lactations, proven in three independent studies. The studies showed increased production of 1,872, 3,000 and 3,200 pounds of milk per cow per lactation. Based on just 1,872 pounds at $12 per hundredweight (cwt), that yields an additional $224 profit per cow per lactation.

Once fresh, cows need diets with a positive DCAD, which buffers the rumen and raises the rumen pH, decreasing the chances of rumen acidosis, Corbett explains. Lactation rations in the range of +35 to +45 meq per 100 grams of ration dry matter result in higher DMI early in lactation and higher milk yield. DCAD levels in lactating cow diets can be increased by adding a safe, high-quality feed grade potassium carbonate, Corbett says, plus a rumen buffer.

Utilizing the information available on formulating rations with negative and positive DCAD is another tool that can be beneficial in maximizing the health, productivity and profitability of the dairy herd, Corbett says. PD

References omitted but are available upon request at

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