Nutrition Plus
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Dairy Nutrition Plus

Volume 13, Issue 2 March 2017


Use Nutrition to Help Combate Heat Stress

Use Nutrition to Help Combat Heat Stress

The calendar may say March, but it’s time to get your summer nutrition plan in place. If you wait for heat stress to occur and then decide to take action to minimize the negative effects of heat stress, you are already behind. Abrupt ration changes can cause problems of their own.

The goal, says Bob Collier, professor of animal sciences at the University of Arizona, is to formulate an action plan for nutrition before heat stress starts. The plan should be specific. For example, when the temperature-humidity index (THI) hits this number, we do this. Or when feed refusals increase above x we do this. Work with your nutritionist to develop a list of nutritional management strategies to combat heat stress that is tailored to your dairy.

These nutrition strategies should be used in conjunction with a cooling program that is also tailored to the conditions at your dairy. Shades, fans, soakers and nutrition all play an important role in minimizing heat stress for dairy cows. While cooling alone makes a difference, when combined with proven nutritional strategies, the results can be even better.

The Effects

Heat stress causes more than just a drop in dry matter intake (DMI) and lost milk production. Cows lose a lot of potassium from sweating and panting. Thermal stress has been shown to increase potassium requirements by as much as 12%, explains Collier. Research also has shown that heat stress increases the buffering requirements of the rumen, and it suppresses immune function.

It also causes changes in cow behavior. Cows drink more water, eat less during the day, often don’t display estrus and they seek out shade. When it is hot, “cows instinctively want to stay in the shade,” says Collier. “They will move with the shade structure’s shadow, and they will choose to stand in the shade even when fans and soakers are running at the bunk.”

Cows perceive that the shade is cooler. Heat-stressed cows also will choose to lie in the alley in wet manure instead of the stalls. The increased exposure to manure combined with a suppressed immune system leads to more cases of mastitis during heat stress.

But if you can control the cows’ behavior, you can reduce the incidence of disease and minimize heat stress. For example, in a north-south oriented barn, afternoon sun forces the cows to seek shade away from the feedline where the fans and soakers run. Installing a curtain on the west side of the barn to block the afternoon sun provides shade and encourages cows to eat feed and rest in their stalls. Having a curtain allows you to take full advantage of the soakers and fans at the feedline. Otherwise, when the sun hits, the cows leave to seek shade.

The Solutions

Cooling cows is a top priority. Shades, fans and soakers all play an important role in combating heat stress. So too does nutrition.

The first step is to talk with your nutritionist about implementing a summer ration. A summer ration may, for example, include higher quality forages with higher rates of digestibility to help reduce the total heat load created from digestion. Lower quality forages take more time to digest in the rumen and therefore generate more heat.

Another summer ration strategy is to increase the nutrient density of the diet by adding concentrate or fat to the diet. Supplements such as buffers, ionophores, yeast and additional potassium also can be helpful. What you choose should be tailored to your dairy. It should be based on available feeds, cost, milk price and room in the diet, explains Collier. Cows should be acclimated to the summer ration before heat stress begins. Then, if additional nutritional changes are needed to help cows’ maintain DMI, the changes will be smaller and less stressful to the cows’ digestive system.

Lactating cows are the cows most in need of a summer ration. Dry cows and close-up cows should already be on a diet tailored to their needs. However cooling dry and close-up cows is tremendously important. (Please see "It Pays to Cool Dry Cows" in this issue.)

Check water availability. Cows need 2 to 3 linear inches of waterer space. Tanks should be shaded and clean with ample water pressure to keep up with demand during warm weather – especially exit lane waterers.

Once heat stress begins, pay close attention to feed refusals by pen. When feed refusals increase, it’s time to alter feeding management. Feed more of the ration at night, and push up often to encourage intake. If DMI cannot be maintained by feeding during the cooler hours of the day, nutrient density can be recalculated. Remember, the cow’s nutrient requirement does not change during heat stress; changes in feeding management and nutrient density can help cows meet their needs.

You’ll also want to track the incidence of acidosis. If you see an increase in acidosis, adding more buffers to the diet can help.

It’s also a good idea to track the temperature-humidity index at your dairy. THI quantifies the severity of heat stress. Cows experience heat stress when the THI rises above 68. Anytime the THI hits 80 during the day, death losses may increase – especially in sick cow pens. Even with proper cooling and nutritional strategies in place, when the THI climbs above 85, severe heat stress and losses can occur.

Sick cows and high-producing cows are the most susceptible to heat stress. They are already stressed by illness or by high milk production, and heat stress can tip the balance to disease or death. Many herds don’t cool sick cow barns, says Collier. But this is where heat stress can quickly lead to increased death loss.

There is a lot we can do to minimize heat stress. Cooling, combined with nutritional management strategies, can make a big difference to limit losses and keep cows healthy and productive. Talk to your nutritionist today to develop your nutrition action plan for heat stress.

Happenings DNP Focuses on Export Quality with Freight Forwarding Partner

Mediterranean Shipping Company carrying Dairy Nutrition Plus shipments
Photo Credit: Agustin Alapont Castilla
The ASYA, a trans-Atlantic cargo vessel owned by Mediterranean Shipping Company, carries Dairy Nutrition Plus shipments from the United States to Saudi Arabia.

With the completion of a major expansion to its SoyPlus® manufacturing plant this year, Landus Cooperative™ has been focused on expanding its in-house transportation team while continuing to strengthen a decade-long relationship with a trusted transportation partner.

Approximately 50 percent of all soybeans purchased from Landus Cooperative’s 60+ grain locations in Iowa will be manufactured into SoyPlus. And much of that is destined for overseas ports. So to ensure the high-quality, high-bypass protein source remains high quality, Landus Cooperative has called on freight forwarder TSC Container Freight to assist in managing shipments of the Dairy Nutrition Plus™ product line to Costa Rica, Saudi Arabia, Australia, Chile, South Africa and Europe.

By working with a freight forwarding partner, Landus Cooperative is prioritizing its continued compliance with the Food Safety and Modernization Act (FSMA) and its focus on safe, consistent products.

“We find increased value in partnering with a freight forwarder that specializes in shipping feed ingredients and understands as much as us the necessity of transporting feed safely,” said Mark Cullen, chief animal nutrition officer overseeing the Dairy Nutrition Plus line of quality feed ingredients.

That’s one reason the farmer-owned cooperative has built a decade-long partnership with the company. As a subsidiary business of the Scoular Company, which is known for its expertise in grain and feed ingredients, TSC acts as the company’s agent to secure space on huge ocean cargo ships.

“When you’re shipping a feed product that helps produce milk for consumers to buy in the grocery store, your distribution process has to be flawless,” added Cullen.

Preserving the integrity of that brand, and the quality of the cooperative’s products, remains at the forefront for the Landus Cooperative transportation team and the freight forwarding specialists assisting them as SoyPlus manufacturing grows to meet global market needs.

From the Maternity Pen It Pays to Cool Dry Cows

Even if you have to build a barn, it pays to cool dry cows. New research reported in the December issue of the Journal of Dairy Science shows that for 89% of the cows in the United States, cooling dry cows is profitable – even if you need to build a barn to do so. If dry cows are already housed in a barn and you just need to add soakers and fans, doing so is very profitable.

Photo courtesy of Bob Collier, University of Arizona
Photo courtesy of Bob Collier, University of Arizona

Researchers at the University of Florida sought to quantify the economic loss from lost milk production if dry cows were not cooled. Using daily weather data from each of the 50 states from 2007 to 2013, they determined that, on average, U.S. dairy cows are under heat stress 96 days each year.

Using milk production losses from 11 previous studies, they calculated that, on average, heat stress would reduce milk production by 986 lbs per cow in the next lactation. (Losses per cow do not include first calf-heifers.) That equates to a loss of $87/cow or $810 million for the dairy industry each year just from lost milk production.

When examined by state, milk production losses per cow in California, Wisconsin, New York, Florida and Texas were 1,150 lbs, 769 lbs, 853 lbs, 2,639 lbs and 1,993 lbs, respectively. The value of that lost milk production was $101, $68, $75, $233, $176/cow/year respectively.

Next they conducted an economic analysis to determine if an investment in soakers and fans, and even a barn for dry cows, was feasible. Additional feed costs, cooling equipment utilities and maintenance were all included in the analysis. The researchers ran several scenarios to compare different milk prices and a variety of other factors. All scenarios showed that cooling dry cows pays.

Using a milk price of $15.42/cwt, they found that it takes just 9 days of heat stress for cooling dry cows with soakers and fans to pay. If, however, a barn with fans and soakers is needed, it takes 81 days of heat stress for the investment in cooling dry cows to pay. It’s time to invest in cooling for your dry cows.

You can read the full paper, “Economic Feasibility of Cooling Dry Cows Across the United States,” in the December Journal of Dairy Science.

Consultants Corner You Can Prevent Hyperketonemia

Jessica McArt
  • By Jessica McArt
  • Cornell University

Subclinical ketosis, also known as hyperketonemia, affects approximately 45% of all postpartum cows in a herd. Of those affected, only 10-15% show clinical signs. That means 85-90% of cows affected by hyperketonemia have a poor transition into lactation that goes unnoticed while health and milk production suffers.

Because the energy demands for milk production cannot be met by feed intake alone, cows often experience a negative energy balance as they transition into lactation. In order to maintain homeorhesis (a normal state) during this period of negative energy balance, cows break down adipose tissue to produce non-esterified fatty acids (NEFA). These NEFAs are then partially converted to ketone bodies and used as an alternate fuel source to meet the cow’s energy needs. Excessive production of β-hydroxybutyrate (BHB) can lead to hyperketonemia. While hyperketonemia does commonly occur, it is also highly preventable. Each case of hyperketonemia carries an average price tag of $289 per cow. With a 30% incidence, the cost per every 1,000 calvings is $86,700. That cost includes diagnostic, treatment and labor cost as well as lost milk production, reduced reproductive performance, and a higher risk for metritis, displaced abomasum and early lactation culling.

First Determine Herd Prevalence

Cow-side blood BHB meters work well to diagnose hyperketonemia on farm, and they are more accurate than urine or milk tests. Hyperketonemia is defined as a blood BHB concentration ≥ 1.2 mmol/L. Blood BHB concentrations of 1.2-2.9 mmol/L are often classified as mild or moderate while blood BHB concentrations ≥ 3.0 mmol/L are classified as severe. Some cows show clinical signs of ketosis with a mild BHB test result and others never show clinical signs even with severe hyperketonemia.

To determine the prevalence in your herd, sample at least 20 cows from 3 to 16 days in milk. This provides a snapshot of your herd. If 5 of the 20 cows tested have a BHB ≥ 1.2 mmol/L, your prevalence is 25%. Generally, the actual number of cows experiencing hyperketonemia during this period will be about twice your prevalence rate because some were previously hyperketonemic and resolved before testing and others will develop hyperketonemia after testing. This means the incidence of hyperketonemia within your herd is approximately 50%; so about half of your cows will be hyperketonemic at some time during early lactation.

The prevalence found determines your testing and treatment plan.

  • If herd prevalence is ≤ 15%, use monthly testing to monitor the herd.
  • If herd prevalence is 15 to 40%, sample cows at 3 to 9 DIM twice weekly.
  • If herd prevalence is ≥ 40%, consider blanket treatment starting at 3 DIM.

Work with your veterinarian to develop a testing and treatment plan that is specific to your dairy. Remember to treat hyperketonemic cows found during monitoring and testing.

Focus on Prevention

A good transition cow management plan can minimize the prevalence of hyperketonemia. Herd prevalence levels of 10% or less are achievable. Commonly recommended prevention strategies are listed below:

  • Feed a controlled energy diet during the dry period.
  • Feed rumen protected choline and monensin throughout the transition period.
  • Strive for a stocking density of 100% or less in all dry cow pens.
  • Maintain a fresh pen stocking density of 85% or less.
  • Minimize the number of pen moves before arrival in the maternity pen.
  • Provide fresh heifers separate housing.
  • Maximize cow comfort.
  • Minimize heat stress – including in the dry cow pens. Cows need be able to lie down when they want and not spend extra energy to dissipate heat.
  • Maximize DMI throughout the transition period.

By focusing on the nutrition and management strategies listed above, many herds achieve a prevalence of 10% or less. Prevention is well worth it. When you decrease the prevalence of hyperketonemia from 20% to 10%, it saves nearly $60,000 across 1,000 calvings. Talk with your veterinarian and nutritionist to determine how best to implement these prevention strategies on your farm.

Beyond Bypass DCAD’s Effect on the Rumen Environment

Research has repeatedly demonstrated that manipulating the dietary cation-anion difference (DCAD) in the diet can improve feed intake, milk production and the acid-base status of animals. However, little is known about the effects of the individual ions on the rumen environment. Researchers at the University of Maryland set out to learn how the individual cation and anion sources (sodium, Na; potassium, K; and chloride, Cl) affect the rumen environment and fermentation.

Las Uvas Dairy, NM - Dairy Nutrition Plus - SoyChlor®

They fed five different diets to compare a base diet to ones with additional sodium chloride, sodium bicarbonate, potassium chloride or potassium carbonate. The results, reported in the August 2016 Journal of Dairy Science, clearly show that changes in dietary Na and K affect rumen ion concentrations. But the source of the Na, K and Cl in the diet did not matter. Following are a few key points from the study:

  • Adding dietary Na increased the rumen concentration of Na ions.
  • Adding dietary K increased the rumen concentration of K ions.
  • Adding dietary K decreased the rumen concentration of Na ions by 25%.
  • Adding dietary Na had no effect on the rumen concentration of K ions.
  • Cation source did not affect rumen pH.
  • Rumen VFA concentrations were not affected by cation source, or DCAD.
  • Rumen Cl ions increased with increased dietary Cl.
  • The Na:K ratio in the rumen was on average 2.3-fold higher in cows fed diets supplemented with Na compared to those supplemented with K.

“The study demonstrated that manipulation of dietary strong ion concentrations can alter rumen ion concentrations,” explains Richard Erdman, professor of dairy cattle nutrition at the University of Maryland. “If production and feed efficiency responses to DCAD and potentially ionophores in the diet are affected by rumen NA and K concentrations, then manipulating dietary Na and K could be used to either enhance or diminish those responses.”

You can read the full study, “The Effect of Cation Source and Dietary Cation-Anion Difference on Rumen Ion Concentrations in Lactating Dairy Cows,” in the August Journal of Dairy Science.

Quality Corner You Can Receive SoyPlus RUP Testing Data Today

Dairy NUtrition Plus RUP Testing
In situ RUP testing applied to more than 500 samples of SoyPlus.

An ideal high-bypass protein source depends on consistent RUP levels and high digestibility of that RUP. That’s why SoyPlus is routinely subjected to not just one, but two protein analytical procedures.

For seven years now, the RUP content of SoyPlus has been verified via ongoing in situ (in live animals) testing involving over 500 samples. And more recently, some of those same SoyPlus samples have been subjected to additional evaluation using the Ross in vitro (in test tubes) assay to determine protein digestibility.

Developed recently at Cornell University by Dr. Debbie Ross and Dr. Mike Van Amburgh, the Ross method estimates the digestibility of protein that would escape degradation in the rumen. The combination of these two procedures has again verified that the protein in SoyPlus is well over 60% undegradable in the rumen, that the RUP content of SoyPlus is very consistent and that this RUP is highly digestible.

Consistency matters, and the rigorous testing applied to SoyPlus ensures that what we claim our product to be is what you actually get with this high-bypass protein product.

Ask to see the data. Contact a Dairy Nutrition Plus representative today to learn more about these testing methods and how consistent RUP content and consistent RUP digestibility impact animal performance and your bottom line.