Author: jtechtmann

By Margaret Quaassdorff & Casey Havekes, Cornell Cooperative Extension Regional Dairy Management Specialist

Introduction:

It is widely accepted as an industry standard that calves should double their birth weight by 60 days of age. To accomplish this target, or even exceed it, calves must receive a sufficient supply of required nutrients. Often this results in calves being fed high amounts of milk and/or milk replacer. An important consideration when feeding high planes of nutrition is that the more liquid that goes into the calf, the more liquid there will be coming out. Loose manure from calves on a high milk diet can easily be confused with nutritional scours. The first objective of this article is to help calf raisers understand and calculate nutrient requirements. Secondly, the article strives to help calf raisers understand the difference between nutritional scours and normal loose manure, and if action is necessary to improve the health and well-being of these calves.

Energy Requirements of Calves:

A calf’s nutrient requirements can be broken down into the following categories: energy, protein, vitamins, and minerals. Like all growing animals, the nutrients provided to the calf will first go towards maintenance and then any remaining nutrients will go towards growth. So, you may be wondering how we should feed these calves to ensure there are sufficient nutrients available to meet our growth targets. That is an excellent question, and we will attempt to walk you through the steps below to calculate energy requirements, specifically. Please note, that your local Extension Support or trusted advisors are also available to help you. Maintenance requirements for calves can be calculated with the following equation:

MEmaintenance Mcals = 0.1 x BW(kg)^0.75

If we take a 41 kg (~90 lb) calf, for example, her maintenance requirement is going to be 1.61 Mcals metabolizable energy (ME)/day. An important note is that this equation does not consider temperature or breed which are both very important when calculating energy requirements. During cold weather, calves require additional energy to meet their maintenance and growth requirements. Specifically, for every °C the temperature drops below the calf’s thermoneutral zone (15°C or 60°F), the calf’s energy requirement is going to increase by ~0.03 Mcals ME. This may not seem like a big increase, but if you think about a very cold winter day where the temperature is -15°C (5°F), that calf’s energy requirement for maintenance alone is going to be increased by 0.9 Mcals ME (i.e. 0.03 * 30°C difference between thermoneutral temperature and outside temperature).

So now that we understand maintenance requirements, we need to calculate how many additional nutrients are required to achieve growth targets. The energy requirement for growth can be calculated with the following equation:

MEgrowth Mcals = [0.84 * BW(kg)^0.355 * (ADG (kg/d)^1.2)]

If we take that same 41 kg calf and we would like for her to gain 0.8 kg/day, then her growth requirement is going to be 2.4 Mcals ME. Now, if we combine her growth and maintenance requirements (assuming it is a nice spring day with a temperature of 16°C or 61°F), we get a total energy requirement of 4.01 Mcals ME. Once we have a total energy requirement for that calf, we must calculate how much milk or milk replacer is required. We can calculate energy content of milk replacers based on a series of formulas – please reach out to Casey or Margaret, or a trusted advisor if you need help calculating these values. A general assumption is that most milk replacers will have an energy value of ~4.2 – 5.0 Mcals / kg of dry matter (DM), while Holstein whole milk is closer to 5.3 Mcals. If we take a 28:20 milk replacer that is supplying 4.74 Mcals ME / kg DM, we can then calculate how much we need to feed to meet the requirement of 4.01 Mcals by dividing 4.01 Mcals (required) by 4.74 Mcals (supplied). By doing this simple calculation (4.01 / 4.74), we get a value of 0.85. This means that this specific calf requires 0.85 kg of this specific milk replacer to achieve her maintenance and growth requirements. Calculating feeding rates to meet requirements is important; however, it is only one piece of the puzzle. Another important aspect relates to management of these milk-based diets. The remainder of the article is going to discuss key management practices for feeding calves milk and/or milk replacer diets, particularly those on a high plane of nutrition.

Please note, the calculations above are specific to °C and kg, thus °F and lbs cannot be substituted into the equations.

Loose Manure vs Nutritional Scours:

Normal loose manure is often confused with nutritional scours. It is important for those who raise calves to be able to distinguish between the two. True nutritional scours is diarrhea (excessively and abnormally loose or watery stool), and has negative consequences for the health and growth of our calves. It can be caused by a number of management practices associated with the composition, cleanliness, mixing, prepping, or delivery of milk or milk replacer. It differs from normal loose manure that is typical in calves fed a high plane of nutrition (10+ liters/day) of properly mixed and delivered milk or milk replacer. Nutritional scours is the result of digestive upset, not merely volume of milk going through a calf’s system. More milk in means more liquid manure coming out. A calf with loose manure that is otherwise alert, healthy, growing, and showing no signs of dehydration (i.e. sunken eyes, poor suckle reflex, lethargy, depression) is not suffering from nutritional scours.

Figure 1. This is normal manure from a calf on a high plane of nutrition. Without knowing further background information about the calf, it could also be a sign of nutritional scours.

Causes of True Nutritional Scours:

• Excessive lactose in the milk replacer (>300 grams/day or >0.75% of body weight)
• Poorer quality milk replacer (those that incorporate primarily alternative proteins from plants vs milk proteins)
• Incorrect mixing of milk replacer or additives (undermixing leaving clumps of powder still intact, overmixing causing particles to crash out of solution, wrong mixing temperature)
• Incorrect dilution or percent total solids (too low or too high)
  • Cows’ milk: 12.5%
  • Acceptable range for milk replacer depending on volume fed: 12%-15%
• Inconsistent dilution (a 1% change in total solids is enough to cause digestive upset; example: 14% solids one meal, 12.8% next meal, 14.2% following meal)
• High bacteria load due to:
  • Improper storage of milk or mixed milk replacer
  • Dirty pasteurizer or buildup in autofeeder tubes or nipples
  • Dirty bottles/buckets or mixing utensils
  • Milk from cows with mastitis or high somatic cell count

How to Troubleshoot:

• Calf appearance
  • Monitor signs of dehydration and perform the “Skin Tent Test” as shown in the picture below:

Figure 2. Evaluate dehydration in calves using overall appearance and the “Skin Tent Test”

• Cleanliness audit
  • Work a trusted advisor to get proper tools to identify high risk areas
• Check for quality ingredients on the milk replacer tag
• Follow directions on the bag for mixing (can be specific to the type of milk replacer)
• Weigh both powder and water, and use a refractometer to check total solids % in milk or milk replacer. Make adjustments accordingly:
  • BRIX % +2 = total solids % for whole milk
  • Check with nutritionist for the correct adjustment for your specific variety of milk replacer as they can differ

Figure 3. Description of equations used to calculate percent total solids of milk replacer

• Place a thermometer in the pipeline or near the sink to check mixing and delivery temperature accuracy
• Keep records during feedings (test and write down % solids, and any health observations)
• Monitor the color of manure (Note: Some pathogenic scours can be whitish in color as well, such as rota- and coronavirus, so color alone is not a diagnosis)
• Perform a fecal culture (work with your veterinarian to determine/rule out possible pathogen presence)

What Else Helps?

• Continue feeding calves throughout their bout of scours
  • Calves’ bodies and immune systems need nutrients to fight pathogens and for continued growth
• Direct-fed microbials and prebiotics
  • Promotes, supports and strengthens immunity
  • Common ingredients include:
    • Hydrolyzed yeast cell wall products (intestinal integrity)
    • Beta-glucans from live yeast (primes the immune system)
    • Beneficial bacteria such as Bacillus subtilis (inhibits bad bugs)

Conclusion:

In summary, in order to meet growth targets and performance goals calves require sufficient nutrients. Calculating these requirements can appear to be overwhelming, but please reach out to one of us, or your trusted advisors for assistance. It is also important to remember that the information provided in the first half of this article is exclusive to nutrients supplied by liquid feeds. Providing solid feed is equally important (and now a requirement for the FARM 4.0 program starting at 3 days of age!) in promoting growth and overall success during the pre-weaned phase of life. Feeding calves high amounts of milk or milk replacer in order to meet elevated growth targets/goals can often result in loose manure. Normal loose manure is often confused with nutritional scours, but it is important to understand that properly feeding more milk to calves shouldn’t result in nutritional scours as we’ve described it here. If you suspect that true nutritional scours is affecting your calves, it’s time to find out why.

To watch the webinar recording of this topic and others in the Critical Calf Care series visit: https://www.youtube.com/playlist?list=PLBMGyzTr13d…

Margaret is the regional Dairy Management Specialist for Cornell Cooperative Extension’s Northwest New York Dairy, Livestock and Field Crops Team. She provides dairy producers with technical and practical resources in the areas of production and nutrition management, calf care, and precision dairy technologies to improve herd management and cow health. To contact Margaret, email maq27@cornell.edu and refer to the NWNY Team’s website and/or blog.

Casey Havekes is a Dairy Management Specialist on Cornell Cooperative Extension’s North Country Regional Ag Team. Casey’s recent focus has been on calf health, management and nutrition, transition cow management, and lactating cow nutrition. For more information please refer to the Team’s webpage and/orblog, or reach out to Casey at cdh238@cornell.edu.

By Megan Wildman, Purina Calf & Heifer Specialist

When choosing the right milk replacer for your calves, start with your goals for the calves. Do you want your calves to get the most growth possible during the most efficient stage of life? Are you trying to boost their immunity because you’re fighting a disease challenge? Are you trying to help them gain through extreme heat or extreme cold? It’s helpful to ask yourself these questions.

What’s the outside temperature?

Young calves have a thermal neutral zone between 60-75°F. Calves may undergo cold stress at temperatures below the thermoneutral zone. Calves less than three weeks of age can experience cold stress at 60°F, and calves older than three weeks of age can experience cold stress at 42°F1.

If calves don’t get enough energy in their diet during cold stress conditions, they will use their body fat as an energy source. Energy will be diverted from supporting growth and immune function to maintaining core body temperature. As a result, calves may experience weight loss and impaired immune function. The volume of liquid nutrition required for calves to achieve 1.5 lbs. average daily gain (ADG) varies under different temperatures1 (Table 1).

Do you increase feeding rates in winter?

Increase the quantity of milk or milk replacer to meet the increased caloric needs of cold stressed calves. Adding a third feeding (preferably late at night) is a great way to deliver added nutrition. If already feeding calves three times a day, increase the volume at each feeding. Keep the solids concentration the same and bump up the total volume of the solution. Feed a full potential diet of at least 2.5 pounds of milk solids from 8-12 quarts of milk or milk replacer per day.

It’s important to have the correct protein to fat balance when increasing the quantity of milk replacer fed. The traditional method of feeding approximately 2 quarts of 20:20 milk or milk replacer twice a day falls far short of the energy requirements needed to support both maintenance and growth of young calves, especially in colder temperatures. To increase energy levels, look for a milk replacer with at least 26% protein and 20% fat. Milk replacers with more than 20% fat may decrease growth and hinder starter intake, especially when temperatures moderate (Table 2).

Are you providing the right energy sources?

The energy in milk or milk replacer is predominately derived from two sources – carbohydrates and fat. The predominant source of carbohydrates in milk or milk replacer is lactose. Milk replacer is generally comprised of about 35-45% lactose. Carbohydrates are rapidly digested and provide nearly instant energy, while fat is stored for longer-term use and is a reserve energy source mobilized as needed.

The source of fat in milk replacer is an important and often-overlooked consideration. Milk fat, due to its high value in the human nutrition market, is not typically added to calf milk replacers, leaving alternative sources to supply fat such as lard, choice white grease or tallow.

The fatty acids that make up fat are classified as short-chain, medium-chain, and long-chain fatty acids. The length of the chain depends on the number of carbon atoms in the structure of each fatty acid. Medium-chain fatty acids are highly digestible, as they are absorbed directly from the small intestine to the liver, where they are converted to available energy.

Certain polyunsaturated fatty acids (omega-3s) modulate the inflammatory response by the calf’s immune system, allowing the calf to recover more quickly from an immune challenge. The key to optimizing fatty acids in milk replacer is to mimic levels present in cow’s milk. While most cow’s milk fat is made up of long-chain fatty acids, it also contains 8-12% medium-chain fatty acids.

Are you supporting your calves’ microbiome?

Calves are born with a sterile gastrointestinal (GI) tract – essentially a blank slate ready to be populated with microorganisms. Establishing a healthy, balanced gut environment as soon as possible is critical to the health and development of pre-weaned calves.

The gut microbiome (or gut microorganism population) plays an important role in calf health, as 70% of the calf’s immune system resides in the gut.

The gut microbiome plays an important role in disease prevention and maintaining calf health, especially during times of stress when there is higher susceptibility to disease. Feeding probiotics pre-weaning can help establish a healthy microbiome and support immune strength. Research showed probiotics can help optimize bacterial diversity in the gut that may help address health challenges.

A healthy gut microbiome helps:^1,2

• Promote and maintain calf immune system health.
• Prime the immune system to stay alert and prepared for disease challenges.
• Stimulate mucous layer production on the intestinal wall to provide a barrier against pathogens.
• Enhance the gut immune response to invading pathogens.
• Saturate the colonization sites on the intestinal tissue.
• Break down nutrients for optimal absorption.

Do you provide fresh water?

Water is equally as important in cold temperatures as it is in the summer heat. Dry winter air can dehydrate calves. Providing adequate water supply helps improve hydration and supports growth by optimizing calf starter feed intake.

Offer warm water to calves immediately after each milk replacer feeding and let them drink as much as they want. Make sure water is 100-105°F to avoid lowering calf body temperatures. For those feeding milk or milk replacer two times a day, add a third water feeding mid-day to help optimize starter intake.

Megan Wildman is a calf and heifer specialist with Purina Animal Nutrition in New York. She joined Purina after working as the Cornell University Research Center herd assistant. While at Cornell, she earned a bachelor’s degree in animal science. She’s a sixth-generation dairy farmer and wants the best for you and your calves. You can learn more about Purina calf products at https://www.purinamills.com/.

¹ Corbett, R. Prime the pump. Bovine Veterinarian. April 22, 2019
² Direct-Fed Microbials (Probiotics) in Calf Diets. Bovine Alliance on Management and Nutrition. 2011

Compiled by Kelly Driver

Have you ever heard the phrase “where there is a will, there is a way?” In this post, I will share some of the most useful and innovative ideas I have come across while visiting with calf raisers. Many of these ideas came about as people pondered a better, more labor efficient way of caring for their youngest herd members. At Calf-Tel our slogan is “Heart Meets Smart” and I believe sharing these ideas epitomizes that slogan. May they be ideas that help bring efficiency…or better yet, spark an idea that makes your workday a bit easier.

Hutch Movers

Pictured here are two different styles of hutch movers that have been built. Both of them easily attach to the front end of a skid loader or tractor and can be carefully inserted into the front door opening on Calf-Tel hutches to lift the hutches and move them for cleaning and disinfecting between calves.

Pen Wash Racks

A farm in Wisconsin built these clever wash racks for moving and cleaning their Calf-Tel pen pieces between calves. The racks can easily be picked up and moved by a tractor with pallet forks and returned to the barn for use with the next group of calves.

Marking Calf Pens

Here are just two ways that I have seen to mark calf pens, with different colors of bands, pins or tape indicating whether a calf is being weaned, treated, getting electrolytes, or requires extra monitoring because of a difficult birth. Calf-Tel is now offering pen stickers that can be placed on pens to help track calf information and notes as well. Find them here: Calf-Tel.com

Calf Mover

This is one of the easiest ways we have seen to move calves from the maternity area to the calf hutches or barn. This box can be lowered to ground level to load and unload the calf easily, saving any heavy lifting by the calf care team.

Windbreak

This simple windbreak is made from a piece of shade cloth and placed on every fifth hutch in a row and the calf team tells me they really help keep the snow from drifting in the front opening of the hutches and provide a nice windbreak for the calves. Each end of the fabric is attached to a piece of 2’X4’ lumber to weigh it down and hold it in place.

Tethering Hutches in Windy Areas

If your hutches are located in a windy area, this idea might be helpful. A calf team fastened this cable catch to the top of each hutch in the row. They ran the cable the length of the whole row and fastened it to stakes in the ground at each end.

Feed Savers & Rain Covers

Are you tired of tossing away grain that gets wet in the rain? Calf-Tel offers a feed saver hood (pictured at the right) that easily attaches to the fence in front of the hutch, keeping calf starter better protected from the elements. Are you feeding weaned calves at outdoor troughs? This calf raiser cut leftover pieces of milking parlor wall board wide enough to help keep the rain from filling the trough with water. They find the calves waste much less grain with these in place.

Portable Scales

Weighing calves provides accurate birth and weaning weights to assess our calf program. On the left is a portable scale that can be easily moved with a set of pallet forks on a small tractor. The 3 side walls help keep the calf on the scale for an accurate weight, even when they are still wet after birth. The larger scales on the right are also mounted on a floor that can be easily moved by a tractor with pallet forks, making it very easy to move them to different groups or pens at the calf ranch.

Ease of Working in Calf Barns

These two ideas can save a lot of walking for the calf care team in a calf barn. On the left, this farm left an alley behind the pens that is wide enough to push a bedding cart down, allowing them to bed the pens from the rear while the calves are drinking their milk at the front. The calf care cart on right carries everything the calf team needs as they monitor calves each morning. The rolling cart carries gloves, colored pins for marking individual pens, hand sanitizer, medications, a tube feeder, and a book for recording any observations or treatments.

At Calf-Tel we are passionate about helping calf raisers accomplish their goals easily. If you have tips and ideas that you would like to share with others, please email them to kellydriver@hampelcorp.com and be sure to follow Calf-Tel on Facebook.

Kelly Driver, MBA has been involved in the New York dairy industry all her life. In addition to raising dairy calves and replacement heifers, she is the Eastern US & Canada Territory Manager for Calf-Tel. Feel free to contact her at kellydriver@hampelcorp.com with your calf questions or suggest a topic you would like addressed in a future blog.

by Kelly Driver

The newborn dairy calf is born into a dirty environment filled with bacteria, germs, viruses and a host of other microorganisms that can cause disease. This makes the first, critical delivery of antibodies from high quality colostrum so important to setting the calf on a healthy path because the cow’s placenta does not allow the transfer of essential antibodies in-utero. This systemic protection provided by colostrum in calves lasts from 2 to 12 weeks, depending on the quantity and quality of colostrum the calf received, the disease, and the level of exposure the calf is challenged with (Faries).

Additionally, producers have the opportunity to use vaccines to further bolster antibody levels in the calf. Let’s take a quick look at some things to keep in mind when developing a vaccination protocol with the herd veterinarian.

Types of Immunity

The purpose of vaccine usage is to protect the herd from harmful diseases, but to do this the animal’s immune system must develop memory. With each vaccination and booster, the goal is to provide the necessary protection by triggering the immune system to recognize the disease.

There are two basic types of immunity: passive and active. Passive immunity is immediate as it begins working as soon as the antibodies are absorbed, but this type of immunity is also quite short lived. Passive immunity typically offers about one week of protection, according to Dr. Rob Lynch, DVM in Cornell University’s Pro-Dairy Calf and Heifer Management course. He notes that passive immunity may be reactive, but the body doesn’t develop a long-term resistance and typically these products offer about one week of protection, according to Dr. Lynch (Lynch, 2020).

With active immunity, the body may have a delayed response, taking a few weeks to develop the immunity, but the results can last months or years. Modified live vaccines, bacterins and toxoids can all stimulate active immune responses.

Dr. Scott Nordstrum, DVM, associate technical director of ruminant life cycle management at Merck Animal Health, explains that calves have three basic sources for their immunity:

1. Maternal antibodies from colostrum provide passive immunity for disease protection. This is essential to protect a newborn for at least the first two to four months of life. As time passes, these maternal antibodies dissipate.
2. Innate immunity is the built-in response to disease challenges that nearly all healthy animals are born with.
3. Active immunity is protection from disease developed after exposure to disease or through vaccinations.(Source: Ryan)

Developing a Vaccination Protocol

Considering the possible diseases your calves and heifers could be exposed to is a great way to kick off a risk assessment with your herd veterinarian. It is also beneficial to consider where and when it will be easiest to safely handle the animals and get vaccinations completed on a regular basis. What additional labor may be required to complete the task?

After the thorough risk assessment is completed, work with your veterinarian to select vaccines. Giving consideration to safety, timing of vaccinations (and any necessary boosters), efficacy of the vaccine, and proper handling should all be included. Taking the time to read the vaccine information insert can provide many of the details about dosage, age and pregnancy status, proper storage, route and frequency of administration, and volumes of other valuable information.

Types of Vaccines

In general, there are three types of vaccines: Modified live, killed/inactivated, and a combination of both. The University of Minnesota Extension provides a nice explanation of each:

Modified live vaccine (MLV)

• MLVs are non-disease-causing versions of a virus or bacteria.
• The live virus or bacteria replicate in the animal similar to how the actual disease would, but does not cause the disease itself.
• The replication of the vaccine organism allows the immune system to develop a full response and create proactive immunity with only one dose of the vaccine.
• Many protocols recommend revaccination because not all animals respond to each vaccination.

Killed vaccines

• Killed vaccines do not contain a live virus or organism.
• Killed vaccines contain a dead organism or a specific piece of an organism that is critical to the function of the disease-causing virus or bacteria.
• The crucial difference between killed and modified vaccines is there is not replication with a killed product.
• For most vaccines, the lack of replication means the immune system does not develop the protective memory with just one dose and requires a booster.

Combination vaccines

• Some vaccines contain both modified live and killed products.
• These vaccines can protect against the live portions with one dose.
• The killed portion requires a booster to provide protection.

(Source: University of Minnesota Extension)

Intranasal Vaccines Often Used in Young Calves

One of the challenges encountered when vaccinating young calves is that they have received maternal antibodies that help protect them, but those same maternal antibodies can also neutralize antigens from an injectable vaccine, according to Dr. Nordstrum. “This is referred to as maternal antibody interference. We want to work with the colostrums – not against them. Peer-reviewed research suggests that maternal antibodies can inhibit the immune response to a vaccine in calves until their decline by 6 months of age” (Ryan).

Using an intranasal vaccine actually stimulates a different immune response in cattle. “One of the reasons we love intranasal vaccines is that they are demonstrated to be effective in the face of maternal antibodies because the antigen is introduced in close proximity to the mucosal surfaces,” Nordstrum explains. “They stimulate nonspecific immunity at the mucosal surfaces that helps provide protection against the respiratory pathogens found in the vaccine” (Ryan). This makes intranasal vaccines a good match for young calves and helpful to calf managers battling respiratory challenges.

Common vaccinations for calves and heifers

The central group of vaccines included in any vaccination protocol should be determined with the herd veterinarian during a risk assessment discussion. Often times the diseases are categorized by the body system they affect, such as respiratory or reproductive viruses and bacteria. Another group that may be included in a protocol address clostridial bacteria resulting in diseases like Blackleg, Redwater, and Tetanus.

Scours vaccines may be included in the protocol for pregnant animals prior to calving. Serum antibodies begin to move to the animal’s mammary gland 5-6 weeks prior to calving as part of colostrogenesis. The timely administration of scours vaccines can help provide very beneficial antibodies to the newborn calf through the resulting colostrum, as noted by Dr. Lynch in the Cornell Calf and Heifer Management course.

Handle with Care

Be certain to read labels and store vaccines properly. If vaccines need to be reconstituted, mix them gently. Shaking the bottle could release endotoxins. Several vaccines typically should be in refrigerated storage between 35-45^oF and anytime outside that range can begin to break down the vaccine. Be prepared to keep vaccines out of direct sunlight and in a cool container while using them. In warm weather conditions the challenge is to maintain the vaccine’s effectiveness.

Remember that vaccines are not absolute protection and offer a small piece in helping the host animal. They can aid in the prevention of clinical disease, by triggering the immune system to recognize the disease the animal is exposed to and respond, if the environment and pathogen load are not too overwhelming. A good vaccination program should go hand-in-hand with all the other measures taken to keep calves healthy – proper hygiene, excellent nutrition, and regular consultation with the herd veterinarian.

Kelly Driver, MBA has been involved in the New York dairy industry all her life. In addition to raising dairy calves and replacement heifers, she is the Eastern US & Canada Territory Manager for Calf-Tel. Feel free to contact her at kellydriver@hampelcorp.com with your calf questions or suggest a topic you would like addressed in a future blog.

References

• Armstrong, Joe, DVM. 2020. Cattle vaccine basics. University of Minnesota Extension. Retrieved at Cattle vaccine basics | UMN Extension
• Faries, Floron C., Jr. Cattle vaccines. Texas A&M Agrilife Extension. Retrieved at Cattle Vaccines – When should you vaccinate cattle? (tamu.edu)
• Leadley, Sam. Vaccinating calves in hot weather. Attica Vet Associates. Retrieved at VACCINATING CALVES IN HOT WEATHER (atticacows.com)
• Lynch, Robert A, DVM. November 2020. As presented in Cornell University Pro-Dairy Calf & Heifer Management Course.
• Ryan, Jennifer. (June 2020). The nose knows – internasal cattle vaccines. Veterinary Advantage. Retrieved at https://vet-advantage.com/vet_advantage/the-nose-knows-intranasal-cattle-vaccines/

by Kelly Driver

It is widely recognized that colostrum is the single most important meal for newborn dairy calves, delivering essential nutrition, immunoglobulins (Ig) and other important factors vital to setting up a newborn for lifetime success. Highly anticipated new recommendations about passive immunity standards for newborn calves have been published in the August 2020 issue of the Journal of Dairy Science. So, let’s take a look at what research has shown over the years and what the most recent recommendations offer for both individual calves and herd-level goals, as the industry moves again to further improve calf health and reduce morbidity and mortality in young calves.

The back story.

Passive immunity in dairy calves is evaluated by measuring the serum total protein (STP) or plasma IgG within the first seven days of age. The standard for individual calves to be categorized with successful passive transfer for the past 30 years has been >10 g/L serum IgG, while failure of passive transfer of immunity (FPT) was a serum IgG concentration <10 g/L. These levels correlate directly to STP levels of >5.2 g/dL (pass) and <5.2 g/dL (fail).These cutoffs were established based on higher mortality rates in calves with serum IgG <10 g/L.

Studies have shown.

Research conducted by USDA National Animal Health Monitoring System (NAHMS) in 1991 showed that 41 percent of U.S. dairy calves had failure of passive immunity. With education and outreach, NAHMS reported an improvement to 19.2 percent of calves in 2007 and 13.7% in 2014 studies. Over this same time period, preweaned death rates decreased from 10.8% in 1996 to 6.4% in 2014, but the number of sick calves remained at nearly 30 percent.

Jason Lombard, DVM, MS at USDA/NAHMS reported at the 2020 Dairy Calf and Heifer Conference that in the spring of 2018, a group of eighteen U.S. and Canadian calf experts first gathered to scrutinize the 2014 NAHMS calf data, and discuss other published literature to propose new passive immunity standards. The group emphasized that new standards “needed to be realistic and achievable,” related Lombard to the virtual attendee audience.

Time for an upgrade.

Research has repeatedly shown that healthier calves have improved rates of gain and feed efficiency, resulting in earlier breeding and calving, along with better first and second lactation milk yields. Studies in both dairy and beef calves have also shown reduced morbidity in calves with higher serum IgG levels. Lombard reported the industry group consensus includes four categories, each with corresponding serum IgG concentrations, serum total protein, and Brix percentages. Additionally, the group recommended the percentage of calves that should fall into each category, based on the 2014 NAHMS calf study.

New transfer of passive immunity goals for U.S. dairy calves

Category	Serum IgG categories (g/L)	Serum total protein level (g/dL)	Brix level (%)	Farm Level % calves
Excellent	> 25.0	> 6.2	> 9.4	> 40%
Good	18.0 – 24.9	5.8 – 6.1	8.9 – 9.3	– 30%
Fair	10.0 – 17.9	5.1 – 5.7	8.1 – 8.8	– 20%
Poor	< 10.0	< 5.1	< 8.1	< 10%

Lombard’s group went on to provide two colostrum feeding recommendations, based on the results of the NAHMS Calf Component survey, to help dairy producers achieve the new passive immunity recommendations:

• A single feeding of colostrum, delivering approximately 300g of IgG, fed at approximately 2 hours after birth, or
• Feeding multiple colostrum feedings and delivering approximately 400g of total IgG in the first 24 hours. (Lombard, 2021)

With nearly 90 percent of calves now meeting the previous pass/fail standard of 10 g/L for serum IgG concentration, that standard was successful in challenging dairy producers to improve their newborn calf protocols and colostrum management. Are you ready for the new challenge to further improve calf health and dairy farm success?

Kelly Driver, MBA has been involved in the New York dairy industry all her life. In addition to raising dairy calves and replacement heifers, she is the Eastern US & Canada Territory Manager for Calf-Tel. Feel free to contact her at kellydriver@hampelcorp.com with your calf questions or suggest a topic you would like addressed in a future blog.

References

• Godden, S.M., J.E. Lombard, and A.R. Woolums. 2019. Colostrum management for dairy calves. Vet. Clin. North Am. Food Anim. Pract., 35:535-556.
• Lombard, J. (2020, April 8). New passive transfer standards for dairy calves and how to achieve them. Presented at Dairy Calf and Heifer Association Conference.
• Lombard, J.E., N. Urie, F. Garry, S. Godden, et al. 2020 Consensus recommendations on calf- and herd- level passive immunity in dairy calves in the United States. J. of Dairy Science, 103:7611-7624.

by Sarah Morrison, Ph.D., W.H. Miner Institute

In the first three days after calving, the milk a cow produces changes in composition as it transitions from colostrum to whole milk. This transition takes approximately six milkings after calving (or three days) for this transition to occur. Transition milk provides less concentrated nutrients and bioactives than colostrum, but is still more concentrated than whole milk.

A bioactive is defined as a component that has biological effect.This is an umbrella term, but has received quite a bit of buzz as of late.Bioactives in milk or colostrum can include proteins, fatty acids, hormones, etc. that do not necessarily directly contribute to the nutrition of the calf but can interact with the calf, either at a local level (i.e. the gastrointestinal tract) or systemically for more whole-body action once absorbed by the calf.Furthermore, the extra nutrients in colostrum and transition milk can support growth of the calf and the gut to aid in earlier development.

A study from Michigan State University evaluated the effect of feeding either milk replacer, transition milk, or a 50:50 mixture of colostrum replacer and milk replacer from day 2 to 4 of life. The calves were fed two feedings of colostrum replacer for their first two feedings after birth.Then on day 2 of life, calves started being fed the treatments three times a day with 2 quarts (1.89 L) per feeding. The treatments were milk replacer [27.8% CP and 10.3% fat dry matter (DM) basis which provided 1.17 Mcal metabolizable energy (ME) per feeding], pasteurized transition milk (25.9% fat, 41.8% protein DM basis, and 1.5 g/L IgG as fed, which contained 1.44 Mcal ME per feeding), or a 50:50 mixture of milk replacer and colostrum replacer which provided 14.6% fat, 38.6% protein DM basis, 15 g/L IgG, with 1.28 Mcal of ME per feeding).The figure shows fat and protein provided by the different feeds reported in this study.

The nutrient composition and IgG measured in the transition milk before pasteurization was higher than after pasteurization.This is likely a result of the pasteurization technique used.In this study, they pasteurized the transition milk at 161°F (71.7°C) for 15 seconds, which likely denatured some of the proteins in the transition milk.Recommendations from work done by Dr. Sandra Godden would indicate best practices of heat treatment for colostrum to be 140°F (60°C) for 60 minutes because of the IgG and high solids content.At Miner Institute, we have also heat-treated transition milk following recommendations for colostrum because of the higher solids content.

After four days of age, the calves were fed and managed similarly and body weights, blood samples, and health scores were measured throughout the preweaning period.

Calves that were fed both the transition milk and the 50:50 mixture had an increased body weight of 6.6 lb (3 kg) at the end of the preweaning period compared to the milk replacer group.The calves fed only milk replacer gained 1.23 lb/d (0.56 kg/d), while calves fed the transition milk and 50:50 mixture gained 1.37 lb/d (0.62 kg/d).

The different energy density between the diets fed from day 2 through 4 accounts for some, but not all, of the difference in gain.The authors estimated that the additional nutrients consumed by calves fed the transition milk and the 50:50 mixture would account for 2.84 lb (1.29 kg) of the gain for calves fed the transition milk, and (1.26 lb) 0.57 kg for the colostrum replacer mixture.Therefore, the difference between growth among the treatments would have been residual effects after the treatments ended on day 4 of age.There were no differences in health, with overall incidence of disease very low in all groups.Colostrum and transition milk have been shown to promote the maturation of the intestine, increase absorptive capacity and digestive efficiency. Therefore, some of the difference observed from feeding transition milk or colostrum replacer could be from the other bioactives and their action on development.

We continue to learn more on this topic; however, it seems like there are beneficial effects of feeding transition milk to calves in the first couple of days after colostrum feeding.As with colostrum, it is important to feed clean transition milk that is free of contamination either through heat treatment or good hygiene techniques.

Sarah Morrison, Ph.D. is a Research Scientist at the William H. Miner Agricultural Research Institute in Chazy, NY.Sarah grew up on her family’s dairy farm in Addison County, Vermont.She has a Bachelor’s of Science degree in Animal Science from the University of Vermont and a Master’s of Science and a Ph.D. from the University of Illinois.Her research at Miner focuses on dairy cattle nutrition and management, with a focus on calves and heifers.She can be contacted with questions at morrison@whminer.com.

Reference

Van Soest, B., F. Cullens, M. J. VandeHaar, and M. Weber Nielsen.2020.Short communication: Effects of transition milk and milk replacer supplemented with colostrum replacer on growth and health of dairy calves.J. Dairy Sci. Article in press.

by Kelly Driver

Providing the newborn calf with colostrum, ideally within the first 4 hours of life, is vital to helping it achieve passive immunity. But have we considered what to do when good quality maternal colostrum is not available? A good quality colostrum replacer can provide the healthy alternative.

Failure of passive transfer is big risk. Calves that experience failure of passive transfer (FPT) are more likely to become sick or die in the first two months of life than calves that have adequate immunity. FPT is defined as a blood IgG level less than 10 mg/mL at 24-48 hours after birth. There are many factors that can influence FPT, but the most common revolve around colostrum quality, management, and feeding. Research shows that calves should be fed a minimum of 100 g of IgG within 4 hours of birth, and feeding 150-200 g of IgG is generally recommended to assure plenty of IgG is available for the calf to absorb. (Penn State) We also know that there is a lot of variability in colostrum quality between individual cows, so all colostrum should be tested to ensure only the desired quality is being fed to newborn calves. When available colostrum is low in quality, calf managers may decide to feed either a supplement or colostrum replacer.

Is it a Supplement or Replacer? Colostrum replacers are made from either bovine colostrum or serum and contain 100-150 g of IgG per dose. These products also provide fat, protein, vitamins and minerals, but there is variance among products on the market. For example, fat content can vary widely, but a colostrum replacer will provide more immunoglobulin to the newborn than a supplement product or poor-quality colostrum. When reading the labels, you may find products labeled as “real” colostrum, meaning they contain dairy cow colostrum that has been dried down and heat-treated to eliminate harmful operatives like mycoplasma or Johne’s disease. Serum-based products are the result of blood collected to serve as the antibody source for the newborn calf. These products can transfer IgG to the calf, but can be lacking in the other maternal cells and hormones that are so vital to the newborn calf’s immune system.

There is no way of guaranteeing the effectiveness of a product unless it has been licensed by the USDA Center for Veterinary Biologics. Colostrum supplements are products that are unable to raise the blood concentration of IgG above 10 mg/mL for calves. These products may be used to increase the amount of IgG fed to calves when only lower quality colostrum is available. However, research has shown that when a supplement is added to low quality colostrum, the IgG is often absorbed poorly and FPT rates are higher as shown in the table below. This table summarizes the results of 26 different research trials published in peer-reviewed journals that used nearly 90 different treatments studying colostrum replacer and supplement products and provides a good overview of the various categories performance on average.

Summary of treatment means from 26 published studies investigating colostrum products
	Number of Means	Average	Maximum	Minimum
IgG Intake, g
Maternal Colostrum	19	203	447	53
Colostrum-based Replacer	21	126	210	18
Serum-based Replacer	30	129	260	53
Colostrum-based Supplement	8	157	297	85
Serum-based Supplement	4	96	100	90
Serum IgG, mg/mL
Maternal Colostrum	25	16	27	3
Colostrum-based Replacer	21	11	20	2
Serum-based Replacer	30	9	16	5
Colostrum-based Supplement	8	10	20	5
Serum-based Supplement	6	9	11	7
Apparent Efficiency of Absorption, %
Maternal Colostrum	16	23	36	10
Colostrum-based Replacer	14	33	51	12
Serum-based Replacer	22	25	38	15
Colostrum-based Supplement	7	12	26	6
Serum-based Supplement	4	32	38	25
Source: Penn State Extension Service

Be certain to read the label. Too often colostrum products are selected solely on price, but with many different products on the market, it is very important to look at the labels closely. Since IgGs are the antibodies that provide the newborn calf’s early defense against pathogens, it is important to find a product that guarantees a specific IgG level. Some products may be labeled as providing 120 grams of globulin protein, but in fact deliver less than the crucial 100 g of IgG needed for the calf’s immunity. Globulin proteins actually include other proteins along with the IgG antibodies, so the number can be misleading of the actual effectiveness of the product.

Read and follow the manufacturer’s instructions for feeding. Some products are mixed with water and others are added to existing colostrum, and the number of feedings recommended can also vary. Other products, including those packaged in bulk, offer the option of selecting the IgG dose by using different amounts of powder.

The difference in IgG dosage was studied by Godden et al., (2009a), to determine whether feeding two doses of a colostrum replacer (CR) had further benefit to IgG levels in calves and whether the benefits included all classes of IgG. Each treatment dose contained an IgG concentration of 66.7 g/L, so treatment one received 1.5L and treatment 2 was 3L by volume fed. Treatment group 3 was fed 3.8L of colostrum harvested 20-60 minutes after calving from the dam or stored refrigerated colostrum from one other cow if the dam’s colostrum was not available. All calves in the study were single births, weighing at least 70 lbs., with a calving ease score of less than or equal to 3 on a scale of 1 to 5. All calves were fed the same commercial milk-based replacer after their colostrum feeding. The results shown in the table below and underline that the 24-hour samples for serum protein and IgG in the calves did not differ between 2-dose CR and colostrum, but were greater than 1-dose CR. The apparent efficiency of absorption (AEA) was similar on all treatments, but much better rates of adequate passive transfer (APT) occurred on the 2-dose and colostrum treatments.

	1-dose CR	2-dose CR	Colostrum
Calves, n=	24	23	22
Birth weight, lb.	83.5	86.3	89
Post calving fed, minutes	50	44	44
Total IgG fed, g	100a	200b	271c
Precolostral sample
Serum protein, g/dL	4.5	4.4	4.4
IgG, mg/mL	0.48	0.36	0.38
24-hour sample
Serum protein, g/dL	4.9a	5.5b	5.7b
IgG, mg/mL	9.6a	19.0b	20.7b
AEA IgG, %	35.5	36.5	31.8
Calves with APT, n (%)	13 (54)a	23 (100)b	20 (91)b
Total Ig, mg/ml		20.5	24.5
IgA		0.8a	1.3b
IgM		0.7a	2.5b
IgG		19	20.7
IgG1		17.1	19.5
IgG2		0.9a	1.3b
Source: Kertz from Godden, et al. research
AEA = apparent efficiency of absorption of IgG.
APT = adequate passive transfer (serum IgG at 24 hr. > or = 10.0 mg/mL).
abc Means with different superscripts within a row differ (P<0.05).

High quality maternal colostrum is still the best option for feeding newborn calves. However, there are times and circumstances when colostrum replacer or supplement products can be valuable tools to have available. When selecting a product to use, it is very important to understand if the product is USDA licensed, what the IgG level is, to follow mixing directions carefully, and how many doses should be fed to deliver the calf a minimum of 100 g of IgG within 4 hours of birth.

Kelly Driver has been involved in the New York dairy industry all her life. In addition to raising dairy calves and replacement heifers, she is the Northeast Territory Manager for Calf-Tel. Feel free to contact her at kellydriver@hampelcorp.com with your calf questions or suggest a topic you would like covered in a future blog.

Sources

Godden, S.M., D.M. Haines, and D. Hagman. (2009a). Improving passive transfer of immunoglobulins in calves. I: dose effect of feeding a commercial colostrum replacer. Journal of Dairy Science, 92:1750-1757.

Kertz, A.F. (2009). Calf colostrum replacer can meet IgG needs. Feedstuffs. September 14, p.12.

Lago, A., M. Socha, A. Geiger, D. Cook, N. Silva-del-Rio, C. Blanc, R. Quesnell, and C. Leonardi. (2018). Efficacy of colostrum replacer versus maternal colostrum on immunological status, health, and growth of preweaned dairy calves. Journal of Dairy Science, 101: 1344-1354.

Penn State Extension Service. (2020, April). Colostrum supplements and replacer. American Dairymen, vol. 45, no. 4: 28-32.

Priestley, D., J.H. Bittar, L. Ibarbia, C.A. Risco, and K.N. Galvao. (2013). Effect of feeding maternal colostrum or plasma-derived or colostrum-derived colostrum replacer on passive transfer of immunity, health, and performance of preweaning heifer calves. Journal of Dairy Science, 96: 3247-3256.

by Cari Reynolds, W.H. Miner Institute

As cooler weather sets in and the leaves begin to turn, we humans start to think about ‘sweater season’ and, perhaps even more importantly, ‘soup season’. The nip in the air invites thoughts of warm, hearty meals, and there are few things more inviting than a steaming bowl of soup on a chilly day. While the health benefits of a warm bowl of soup are anecdotal at best for humans (although homemade chicken noodle soup from one particular restaurant in my home region is my sworn go-to for kicking a cold), research continues to explore the impact of heat-treated colostrum on calf health. In fact, companion articles from Cornell University recently published in the Journal of Dairy Science provide new information on how heat treatment may affect other essential immunological components of colostrum and their contribution to calf development.

Colostrum management on farms is one area where cleanliness and quality are imperative. It is important to give the calf a good foundation for her immune system. High bacterial content in colostrum leads to a decrease in available immunoglobulin G (IgG), which lowers the amount available for absorption in the calf. Gut maturation and development are also supported by other complement components present in colostrum, such as growth factors, cytokines, hormones, enzymes, insulin, and insulin growth factor I (IGF-I). Many of these components and their mechanisms in colostrum have been understudied, but advancements in proteomics are allowing for further exploration of these components and their roles in immune and gut development. While it is well-documented that heat treatment reduces bacterial count and preserves IgG fractions, these two studies aimed to further explore what effects heat treatment may have on these other essential components and subsequent impact on the calf’s health and development.

First-milking colostrum from 11 Holstein cows, of which the average Brix percentage was 27%, were collected on one commercial dairy in New York State. Colostrum from each cow was collected 3x over one day post-parturition, homogenized, and divided into two 4-L (1 gallon) bags for a total of 22 paired batches. One bag was placed on ice for 30 min, then stored at 4°C (39° F) for up to 24 h. The second bag was heat treated at 60°C (140° F) for 60 min immediately after filling, placed on ice for 30 min, then stored at 4° C for up to 24 h. Samples from the raw and heat treated colostrum batches were analyzed for somatic cell count (SCC), bacterial contamination, IgG, IgA, complement components, proteins, insulin, and IGF-I. As exhibited in previous work, the heat treatment considerably improved the hygiene of the colostrum. Average SCC of the 11 raw colostrum samples was 470,000 (range 300,000-1,300,000); heat treatment reduced this count by 207,000 ± 68,000, or 36%, in comparison to their raw counterparts. Heat treatment also reduced bacterial counts by 93% in comparison to raw colostrum.

However, heat treatment reduced IgA (which is crucial to development of mucous membranes) by 8.5% when compared to raw colostrum, and reduced IgG by 6.6%. Heat treatment also decreased insulin by 22%, and IGF-I by 10.2%. A total of 328 distinct complement proteins were identified in the colostrum samples, many of which were decreased by heat treatment. While they may not be found in high concentrations, the presence of these complement components are important to the development of the neonatal immune system. The authors then sought to determine if whether or not a reduction in abundance of these components also translated to a biological impairment, or a reduction in their circulating concentrations.

Twenty-two Holstein calves were enrolled to be fed either the raw (R, n =11) or heat treated (H, n =11) colostrum at 8.5% of their body weight (0.87 and 0.91 gallons, respectively). Colostrum was placed in a 43°C (104° F) water bath for 20 min to warm to feeding temperature, and fed to calves within 1 hour of birth via an esophageal feeder. None of the calves received colostrum from their own dam. Calves were moved to a group pen (20 calves/pen) 8 h after feeding, where free-choice, heat-treated milk was offered ad libitum, and calves were treated similarly for the remainder of the preweaning period. Blood samples were collected from each calf immediately before colostrum feeding, and at 4, 8 and 24 h after feeding. Weaning weights were collected at a targeted 64 d.

Calves in both groups demonstrated successful passive transfer of antibodies, with serum IgG concentrations above 10 mg/mL. Weaning weights and average daily gain did not differ between the R and H groups, nor did the levels of serum IgA and IgG 24 h after feeding, despite the reduction of both by heat treatment. Insulin levels peaked at 4 h, but differed at 8 h as decline in insulin in group H was slower than that of group R. No differences in IGF-I were detected between groups. Insulin and IGF-I concentrations were of particular interest to the researchers due to the observed reductions in the heat-treated colostrum. 663 unique proteins were also identified in serum samples; a large number of these were noted to have changed in abundance between the 0 and 8 h timepoints, suggesting a change in the calf proteome following colostrum feeding. Of those serum proteins that were increased in abundance, 41% were also identified in the colostrum samples, and were classified as those involved in immune response and coagulation. These results suggest that many of these immunological factors are present in colostrum and help contribute to the establishment of the neonate immune system, and that lowered abundance in the heat-treated batches did not translate to diminished uptake or effect.

While more investigation of the calf proteome and the effects of heat treatment on complement components of the immune system is still necessary, this research continues to support the method of heat treatment for preservation of colostrum quality. Enhancing our understanding of these complement components and proteins, as well as their roles in development, will provide more opportunities to optimize calf health through management and nutrition strategies. Bring on the cold weather, and bring on those warm bottles!

Cari Reynolds earned a BS in Biology from the University of Scranton and a Master of Public Health from the University of Massachusetts – Amherst. After several years working in the public health sector, Cari returned to her agricultural interests and she is currently a research intern at W.H. Miner Institute. Cari is a Ph.D. student in Animal Science at the University of Vermont, where her research will focus on management and preventative strategies to mitigate diseases that impact both human and animal health. She can be reached at reynolds@whminer.com.

References

S. Mann, G. Curone, T. L. Chandler, P. Moroni, J. Cha, R. Bhawal, and S. Zhang. 2020. Heat treatment of bovine colostrum: I. Effects on bacterial and somatic cell counts, immunoglobulin, insulin, and IGF-1 concentrations, as well as the colostrum proteome. J. Dairy Sci. 103: 9368-9383.

S. Mann, G. Curone, T. L. Chandler, A. Sipka, J. Cha, R. Bhawal, and S. Zhang. 2020. Heat treatment of bovine colostrum: II. Effects on calf serum immunoglobulin, insulin, and IGF-I concentrations, and the serum proteome. J. Dairy Sci. 103: 9384-9406.

By Robert Corbett, DVM, PAS, DIPL. ACAN, Dairy Health Consultant

The most common calfhood disease that results in the highest economic loss to the dairyman is diarrhea. Dehydration and acidosis are the most important issues that have to be corrected in the majority of diarrhea cases. Most individuals responsible for treating sick calves understand the importance of rehydrating the calf and are generally familiar with the use of oral electrolyte solutions.

However, choosing which oral electrolyte to use, unfortunately, is often based on price, or the recommendation of the animal health route person that visits the calf operation. The dairy industry has been suffering from low milk prices for the past several years, so the emphasis on using less expensive products has been a high priority on most operations. It is common for the larger operations to purchase their oral electrolyte product in bulk to reduce the cost per treatment. Even though the bulk products usually contain a scoop that is supposed to deliver the exact dose needed for 1 treatment, this is often increased by a heaping scoop or perhaps more than one scoop on the premise that if a little bit is good, a lot would be better.

When choosing which product to use, it is generally assumed by those purchasing the electrolyte that they are all created equal, so price is the major factor in determining which product to buy. Another factor often considered is how well the calf will drink the oral electrolyte solution so that administering it by stomach tube will be less frequent. When looking at the labels, it is very difficult to compare one product to another. The ingredients in electrolyte are often expressed in different ways such as percentage, grams, milliequivalents per liter, etc., making it next to impossible for those who are purchasing the product to determine which product is the best as far as its ability to rehydrate the calf. In addition to this, there hasn’t been much information provided to the dairyman as far as what concentrations of the individual ingredients are optimum to rapidly restore the normal physiological state of electrolyte balance and hydration. Dr. Geoff Smith from the University of North Carolina has published several articles on this complicated topic for veterinarians, to help them better understand the physiology of rehydrating the calf and correcting acidosis, and thus be able to better advise their clients on this topic. The majority of the information on electrolyte formulation in this article is taken from a chapter written by Dr. Geoff Smith from Veterinary Clinics of North America 2008.

Diarrhea results in rapid loss of the extracellular fluid volume (ECF) with a slight increase in intracellular fluid (ICF). As stated by Dr. Smith “Sodium is the osmotic skeleton of the ECF and therefore of plasma”. Since sodium is the main determinant of the ECF, it must be included in a well-formulated electrolyte product in sufficient amounts to rapidly reestablish a normal state of hydration. There is not an exact amount of sodium that is recommended, but rather a range which was determined by the various research articles that have been published on the topic. Dr. Smith recommends that the sodium concentration be between 90 and 130 mmol/L (millimoles per liter).

Even though calves do lose some chloride with diarrhea, it is not lost in near the amounts that sodium is. Dr. Smith recommends that the chloride concentration be between 40and 80 mEq/L (milliequivalents per liter) with concentrations toward the lower end of the scale probably being better.

Potassium is also lost in the feces of calves with diarrhea. All calves with diarrhea will have a total body deficit of potassium. However, some calves with acute severe diarrhea may actually have a level of potassium that is higher than normal at the same time. When a calf becomes dehydrated, it releases a hormone called aldosterone from the pituitary gland which tries to conserve sodium and water in the kidneys, but at the expense of potassium. Dr. Smith recommends a potassium concentration of 10 to 30 mmol/L in oral electrolyte formulations.

The absorption of sodium in the small intestine is a passive process. There must be some other substance that is actively absorbed in the product in order to facilitate the absorption of sodium. The most common ingredient added to an electrolyte product to enhance sodium absorption is glucose. Glucose is also an important energy source in the diarrheic calf since most calves are in a state of negative energy balance during the episode of diarrhea. Neutral amino acids such as glycine, alanine and glutamine have been shown to increase sodium absorption. Glycine is the most common one added to oral electrolyte solutions. It is generally assumed that including both glucose and a neutral amino acid will further improve sodium absorption above that of glucose alone. Volatile fatty acids such as acetate or propionate have also been shown to enhance sodium absorption. It is also thought that adding a volatile fatty acid to the electrolyte will further enhance sodium absorption as well.

Osmalality is defined as the concentration of a solution expressed as the total number of solute particles per liter. The osmolality of the oral electrolyte solution is extremely important since it has a direct effect on how fast and complete the electrolyte solution is absorbed across the intestinal epithelium into the bloodstream of the calf. Osmalality is quite a complex subject, so only the basic information needed to determine which product would be recommended on farm will be provided. The osmolality of the various electrolyte products varies tremendously. Electrolyte products that are considered to be isotonic (the same osmolality as that of the ECF of the calf) would be in the range of 280-300 mOsm/L (milliosmoles per liter). Those that are extremely hypertonic (much more concentrated) may have an osmolality as high as 700-800 mOsm/L. If the osmolality of the electrolyte solution is significantly higher than the ECF the absorption of the electrolyte is greatly decreased, and could also result in the flow of fluids into the lumen of the intestine, causing the diarrhea to become more severe.

The main factor in determining the osmolality of an electrolyte solution is the amount of glucose in the product. The other ingredients also add to the osmolality. As mentioned previously, glucose not only enhances sodium absorption, but is an important energy source as well. The osmolality at the tip of the intestinal villus is approximately 600 mOsm/L. Therefore, the extremely hypertonic electrolyte solutions could actually result in fluid loss. Since there is already an excess secretion of fluids across the gut membrane, these extremely hypertonic solutions have the potential to increase fluid loss.

The amount of glucose in the electrolyte solution is important as an energy source, but also has a major influence on the osmolality of the product. The general recommendation is that there is between 2 and 3 grams of glucose per kg of body weight of the calf. When choosing which product to use, both the osmolality and the total amount of glucose in the electrolyte must be considered together. The extremely hypertonic electrolyte solutions often result in a slowing down of the abomasal emptying, often resulting in abomasal bloat and/or abomasitis. Dr. Smith recommends that the osmolality of an electrolyte solution be no more than 500 mOsm/L. The osmolality of the oral electrolyte solution is absolutely critical in how fast it is absorbed. For this reason, the dairyman should know what the osmolality is of the product they are using, and each company selling an oral electrolyte should know what the osmolality is. The osmolality is more important than having a high level of glucose in the product.

Almost all calves that have diarrhea will develop acidemia and metabolic acidosis. Correcting this acidosis is an important function of a well formulated oral electrolyte solution. Calves can be rehydrated but still suffer from metabolic acidosis. For this reason, it is important that an alkalinizing agent be added to the electrolyte formulation. This would include bicarbonate, acetate, and propionate. Bicarbonate is effective as an alkalinizing agent in its original state. Both acetate and propionate have to be metabolized in the liver to be effective as an alkalinizing agent. Even though this process is somewhat slower, it does not appear that there is any major difference between these two types of products as far as correcting metabolic acidosis in the calf.

Bicarbonate will lower the pH of the abomasum. If feeding whole milk, this will interfere with the normal clotting of the milk. Most milk replacers use whey protein as the protein source and these proteins do not form a clot in the abomasum, so bicarbonate will not have an effect on these types of milk replacers. Another important point is that a low pH in the abomasum is an important deterrent to bacterial pathogens such as E. coli and Salmonella. These pathogens are susceptible to a low pH and the majority of them are prevented from passing on into the small intestine if a low abomasal pH is maintained.

Acetate and propionate do not lower the abomasal pH. They also facilitate the absorption of sodium as previously mentioned. When metabolized in the liver, these volatile fatty acids are also an energy source, which bicarbonate is not. They will not interfere with the normal milk clotting process of whole milk.

Some electrolyte formulas contain Psyllium or some other gelling factor. This will slow down gastric emptying as well as absorb fluid from the intestine. However, this does not have an effect on rectifying dehydration since the fluid is still in the intestinal lumen and not in the ECF. It is generally not recommended to use these types of agents for this reason. These products will often result in less volume of diarrhea, giving the caretaker a false impression that the calf is improving, when in fact the process of improving hydration is not progressing.

Ideally, administration of oral electrolyte solutions should be spaced evenly between milk feedings to gain the maximum benefit of rehydration. This is often difficult to implement from a management aspect. Milk feedings are rarely spaced evenly apart. If feeding two times a day, it is common that the two feedings are actually spaced less than 8 hours apart so that one shift of employees can handle both feedings. This results in periods of more than 16 hours before the next morning feeding. The electrolyte feeding should be administered midway between the two milk feedings. The ideal situation would be to feed two feedings of oral electrolyte solution per day, one between the two feedings and the other after the last feeding, as far apart as possible. However, this rarely happens without having at least two shifts of employees working in the calf operation.

It is also advisable not to mix the oral electrolyte solution with milk or milk replacer. Milk products also have an osmolality, and when mixed with an oral electrolyte solution, this will increase the osmolality of the combination, likely resulting in an extremely hypertonic solution that could exacerbate the diarrhea problem. If the electrolyte solution has to be fed close to the milk feeding, it might also be advantageous to feed the milk replacer at a level of 12 to 12.5% solids.

Many dairies are feeding an increased level of solids which is beneficial for increasing growth and average daily gain. If currently feeding an increased level of solids, it would be beneficial to reduce the solids to 12 to 12.5% if it is necessary to feed the oral electrolyte solution close to the milk feeding.

There are some common mistakes that are made in the treatment of calf diarrhea. One is discontinuing the feeding of milk during treatment. The milk is the major source of nutrients for the calf and also its immune system. If treated correctly, most calves should be able to maintain a positive weight gain during a bout with diarrhea. Another is the use of oral antibiotics to treat all cases of diarrhea. In general, unless the calf has an elevated temperature, oral and systemic antibiotics are contraindicated. This will have a significant negative effect on the microbiota of the gastrointestinal tract which is important in maintaining the mucin layer of the gut lining, maintaining the gut-associated immune system, competitive inhibition of pathogens, and digestion of nutrients passing into the small intestine.

Following is a summary of the general recommendations of a well-formulated oral electrolyte solution:

• Sodium Concentration 90-130 mmol/L
• Chloride 40-80 mEq/L
• Potassium 10-30 mmol/L
• Osmalality less than 500 mOsm/L
• Strong Ion Difference at least 50 mEq/L
• Contain one or more alkalizing agents: Bicarbonate, acetate, propionate
• Glucose 2-3 grams per kg body of the calf
• Contain glucose, neutral amino acids, and volatile fatty acids to facilitate sodium absorption

In his chapter in VCNA, Dr. Smith has an excellent summary statement to veterinarians: “Practitioners should focus on selecting oral electrolytes solutions that satisfy the following four requirements: (1) supply sufficient sodium to normalize the ECF volume, (2) provide agents that facilitate absorption of sodium and water from the intestine, (3) correct the metabolic acidosis usually present in calves with diarrhea, and (4) provide energy. Additionally, the oral electrolyte should not cause any deleterious effects (such as abomasal bloat). Because veterinarians are often not directly involved with the administration of oral electrolytes to calves, it is important that they examine the electrolyte product being used in their clients’ herds and make recommendations when appropriate.”

It is important that the dairy or calf ranch is familiar with these general recommendations of the levels of ingredients in a well-formulated oral electrolyte solution so they can choose the best electrolyte product possible that is available to them. Proper administration of a high-quality product is necessary to correct dehydration and metabolic acidosis, resulting in a more rapid correction of these issues and a decreased morbidity and mortality rate in young calves. Every dairy should be able to obtain the goal <1% death loss in the milk fed calves if a good nutrition program exists along with good management, hygiene and cleanliness of the environment. This should result in a lower incidence of calfhood diarrhea as well. Implementing the proper use of a high-quality oral electrolyte solution should also be part of a well-managed calf raising operation.

Dr. Robert Corbett, DVM, PAS, DIPL. ACAN earned his B.S. and D.V.M. degrees from Washington State University. He has worked in dairy practices in Idaho, Texas and Utah, including consulting work in 13 states and several countries worldwide. He has published over 160 articles, taught over 500 seminars, and continues to consult with five major companies worldwide involved in providing supplements and additives in dairy cattle rations. This article is reprinted with permission from the March-April 2020 issue of Dairy World, published by IBA, Inc.

by James Umphrey, MS – Eastern US Udder Care & Sanitation Manager for ABS Global

In today’s profit-driven world of dairying, it is important to review all areas and find the opportunities in our operation. Where can we improve and solidify our processes that lead to a successful outcome? In the last few years, we have made unimagined advances in genetics through genomics and sexed semen, getting the best replacement heifers out of our best cows at a higher rate than ever before. High-end heifers are as valuable today as ever, but what about the offspring from the lower end of the herd? Those offspring can create opportunities to bring more value through either the use of sexed high genetic merit semen or beef semen. Either way, producers are looking at the options and making decisions right for them and their operations, then dialing in on the details critical to assuring every calf makes it to become an income stream and not a drag on the bottom line. Every calf needs to do more than survive. They must thrive.

The keys to raising healthy calves are many and complex. One key area is hygiene. To understand hygiene, we need to talk in a similar language. Often these words are used synonymously but truly mean different things:

• Cleaning: the process of removing any visible soils and organic matter including milk, saliva and feces off the surface. This is a great start to any hygiene process but not the end goal for our calf program. In cow prep procedures this is simply a dusting off or dry rub that might be performed before pre dipping the teats.
• Sanitizing: the process where we attempt to reduce the number of microorganisms in an area or on a surface that could be harmful to our health according to public health standards or requirements. Sanitizing reduces, not kills, the number and growth of bacteria, viruses, and fungi.
• Disinfecting: the process that eliminates many or all pathogenic (disease-causing) microorganisms, except bacterial spores, on inanimate objects. The goal of a pre-dip is to disinfect the udder but often falls short due to several factors.
• Sterilization: the process that destroys or eliminates all forms of microbial life (microorganisms). As an example, this is the process applied to surgical instruments in hospitals or in critical areas of an operation where even a small number of bacteria, viruses or spores can cause major issues. Sanitation and disinfection processes are not designed to kill spore formers due to the lack of efficacy of the germicide used or the time needed to kill them.

Numerous microorganisms concern calf raisers. There are also several articles available to review each of these pathogens, their mode of action, and causes of death in calves. A short review of each is below and at what age calves are typically infected.

• Cryptosporidium is a spore-forming pathogen that can affect calves around 5-35 days of age but most prevalent at 7-14 days of age. It is important to note that Cryptosporidium is not generally considered to be a “calf killer” but makes the calf’s immune system more fragile, allowing more opportunistic pathogens to get a stronghold and kill or weaken a calf beyond recovery.
• Rota virus and Coronavirus are both of major concern as they are also most prevalent at 7-14 days of age and are often associated with a calf dealing with a high Crypto load.
• E. coli is a very common pathogen in the calf rearing area and can impact any age but tends to be more devastating very early, with it being most prevalent at less than 7 days of age.
• Salmonella usually hits older calves but can vary greatly depending on the strain.

Hygiene Program for Calf Housing and Equipment

There are two major areas of concern; the pieces that you use to feed calves (buckets, bottles, nipples and mixing utensils) and the housing units. Both are key to keeping calves healthy.

The debate over whether to pressure wash or not is real and is a decision to be made based on your farm factors. My opinion is, if you can isolate the hutches or pen dividers to be pressure washed away from housing units with calves in them, there is little chance of cross-contamination. In general, pressure washing is a great idea and helps ensure that calf housing units are cleaned thoroughly. However, pressure washing can be a point source of bacterial spread to calves when completed within close proximity.

The proper process to sanitize a calf area:

Calf-Tel.com has a good SOP for the process and you can find it here:

Calf Hutch & Pen Cleaning Guide

Steps to the Goal (process)

1. The initial step is to remove the interfering agents like organic load and biofilms by cleaning the visible signs of organic matter with warm water at a temperature of 90^oF.
2. Scrub with a chlorinated alkaline detergent (CAD) at no less than 130^oF water. The CAD helps to breakdown the biofilms and fats that many organisms thrive in. The use of a CAD will also create a higher pH (11-12), which aids the destruction of certain organisms and the removal of the biofilms that can interfere and reduce the effectiveness of your germicide used to disinfect.
3. Rinse with a solution of Chlorine Dioxide (ClO2)/Acidified Sodium Chlorite (ASC) at a minimum of 50-75 ppm per research completed by Dr. Don Sockett, DVM, Ph.D. at of the University of Wisconsin. (Dairy Herd Management) We have seen excellent results at 240-250 ppm if any of the above steps are marginal.
4. Let it dry.
5. Rinse a second time with a solution of 50ppm chlorine dioxide (ClO2)/acidified sodium chlorite (ASC) less than two hours before use, allowing a minimum of one minute of contact with the equipment. This is especially important with nipples/bottles or buckets for milk.

Not all Chlorine Dioxide/Acidified Sodium Chlorites (ClO2/ASC) are the same. It is important to test your germicide regularly with an approved method for the specific product you are using. Understand the chemistry of the product you are using and that there is a verification process to ensure you have the germicidal killing power needed to achieve your calf hygiene goals. Application of ClO2/ASC can be through a drench, spraying or, in some cases, even foamed on calf contact surfaces. Some products on the market do have the ability to foam. Foaming can allow better coverage and will stay wet/active longer, increasing the effective kill of organisms.

Hygiene plays a big part in helping you maintain healthy calves and a healthy bottom line. Dairy operations often have a significant investment in genetics to get a live, healthy calf on the ground. Dialing in the details of the farm hygiene program is one important piece in the puzzle leading to that calf adding to the farm’s income statement.

James Umphrey is currently a Milk Quality Specialist and EUS Udder Care Account Manager for ABS Global Inc. He has worked in the Dairy industry for more than 35 years. Prior to ABS, James was on Faculty at the University of Florida for 18 years. He is a graduate of Auburn University receiving a B.S. in Animal Sciences and M.S. in Nutrition. At ABS he has focused on helping dairymen achieve their goals in all aspects of production and milk quality throughout the Eastern US. Please feel free to contact James at james.umphrey@genusPLC.com.

Source:

Dairy Herd Management. (2012, February). Clean calf feeding equipment in six easy steps. Retrieved from https://www.dairyherd.com/article/clean-calf-feedi…