Autor: Abbey Dugan

By Dr. Marissa Hake, Calf Vet

We’ve historically fed calves to meet their maintenance needs, but not to their full potential. There’s lots of reasons why – milk replacer cost, bucket or bottle size limitations, fear of over-feeding or nutritional “scours”. Or maybe it’s an even worse reason like “This is the way we’ve always done it”. We’re not feeding cows the way we did 30 years ago, so why are we still feeding our calves the same way?

The standard milk replacer feeding program has traditionally been 2 quarts of milk replacer (at 12% solids) fed twice a day. This program was developed to drive calves to eat more grain but leads to poor weight gains in the first month of life. We have fed calves this way to get them off milk and onto solid feed because milk replacer is expensive as compared to grain. One thing that we must remember is in the first 3+ weeks of life, the calf’s rumen is developing, and we cannot rely on grain to provide enough calories for the calf. In addition, calves are only born with 2-4% body fat, so they cannot rely on fat reserves to sustain them in the first month of life either. Restricting calories during the most vulnerable time results in poor growth and increased susceptibility to disease.

We often forget that calfhood diseases impact future lactating performance. So, while it might be a long 2 years until that newborn heifer steps hoof into your parlor, what happens to her in the first couple months of life will pre-determine your return on investment. Research has shown that for each pound of daily gain pre-weaning, milk production increased by 1,540 lbs. in the first lactation or 6,000 lbs. over three lactations. Management and nutritional practices during calfhood have 3-7 times more influence on future milk production than sire selection!

So why is the traditional 2 quarts of milk replacer twice a day not optimal? First, we need to discuss maintenance energy.

What is maintenance energy? Maintenance energy is what the calf needs to just maintain normal body functions, body temperature, and stay alive. This is the energy used before the calf can allocate resources to grow.  A calf’s maintenance energy increases as their body size increases. So, the maintenance needs of a 60lb calf are less than that of a 110lb calf, yet we feed them the same way. Maintenance energy also changes based on ambient temperature and thermal conditions. This means a calf in a wet and drafty pen will require more energy than a calf in a dry, well-ventilated pen, even at the same temperature. Maintenance energy also increases with disease pressure. Sick calves require more energy to mount an immune response. In my opinion, what you don’t pay for in milk the first month of life, you’ll pay for in performance, treatments, and death loss.

The chart below from Cornell University shows how many quarts of 20:20 milk replacer that a calf needs based on body weight and ambient temperature. The blue bars show how much MR is needed to meet maintenance energy (just stay alive) and the yellow bars represent the additional MR needed to achieve 1 lb of gain per day. The left side of the chart is the number of quarts/day the calf would need of 20:20 milk replacer.  As you can see, when temperatures decrease the calves need to be fed more for maintenance energy. Also, you can see that with the traditional 4 quarts/day feeding program the 80lb calf at 10 degrees and the 100 lb calf at 30 degrees and below are not growing and possibly losing weight. Another thing to note is that at optimal temp of 50 degrees, the 100lb calf requires more for maintenance than the 80 lb calf.

(Chart Credit: https://www.vet.cornell.edu/animal-health-diagnostic-center/programs/nyschap/modules-documents/LiquidFeedManagement#:~:text=Whole%20milk%20can%20be%20used,feeding%20when%20fed%20twice%20daily.)

What does this mean? At an optimal temperature of 50 degrees, our 80 and 100 lbs calves will gain very little in the first 3-4 weeks, but will hopefully get to the point where they are eating enough grain to start using that for growth. If the temperature drops to 30 degrees F our 80lb calf is now gaining very little and our 100 lb calf is losing weight! I hear calf raisers say this all the time “I would rather raise the 70-80 lb calves than the big 100lb calves. The smaller ones do better, probably because less stress at birth”. I argue it’s that we’re not optimally feeding those larger calves making them more prone to disease.  Again, remember these calves are less than 4 weeks old and rely completely on milk to survive. We need to provide our calves with more calories to grow and thrive.

According to the Dairy Calf and Heifer Association’s Gold Standards for Heifer Growth, it’s recommended that calves should be doubling their birth weights in the first 56 days of life. In order to achieve this, an 80 lb calf would need to be gaining 1.4lbs+ per day. If we consider our chart above, an 80lb calf at IDEAL conditions with 0 disease stress would require almost 6 quarts of 20:20 milk replacer to achieve 1lb of gain per day.

How to provide more calories for growth

1. Increase volume
2. Increase calories

Increasing volume is relatively easy and most calves can tolerate greater than 4 quarts daily. Smaller calves sometimes can’t tolerate that large of volume so adjustments should be made based on size. If farms can swing the logistics, feeding 3 times a day can also help increase volumes fed. Another option is to increase the caloric content of the milk. This can be done by feeding bulk tank milk or by adding extra milk replacer to your mix. Adding 2-4 extra ounces can increase energy by 25-50. You can also use a higher fat:protein milk replacer or add a balancer to your current milk replacer or bulk tank milk. Make sure that you are closely monitoring the total solids and feeding above 12-13% solids should only be done if calves have access to free-choice water!

One lesson that I’ve learned along the way is “feed calves based on your top 50%, not your bottom 10%”. We need to stop making feeding decisions that hold back our top calves.

Nutrition is just one piece of the calf health puzzle, so make sure to work with your veterinarian and nutritionist to develop your herd health and feeding programs. 

References

https://www.wvdl.wisc.edu/index.php/calf-maintenance-in-cold-weather/#:~:text=to%204%20quarts.-,Feed%20the%20calves%203%20quarts%20of%20milk%20or%20milk%20replacer,instead%20of%20twice%20a%20day.https://extension.psu.edu/feeding-the-newborn-dairy-calf

https://www.vet.cornell.edu/animal-health-diagnostic-center/programs/nyschap/modules-documents/LiquidFeedManagement#:~:text=Whole%20milk%20can%20be%20used,feeding%20when%20fed%20twice%20daily.

https://www.extension.iastate.edu/dairyteam/files/page/files/PracticalEconOfAccelratedCalfFeeding_Tyler.pdf

http://livestocktrail.illinois.edu/dairynet/paperDisplay.cfm?ContentID=358

https://www.progressivecattle.com/topics/feed-nutrition/brown-fat-ensures-survival-in-calves

https://dairy.osu.edu/newsletter/buckeye-dairy-news/volume-21-issue-1/cold-weather-dairy-calf-care

https://dyson.cornell.edu/wp-content/uploads/sites/5/2020/09/Dairy-Replacement-Costs-Writeup-Final1-VD.pdf

Amaral-Phillips, D.M. Dairy Calf Management Practices Impact Future Production. University of Kentucky College of Agriculture, Food and Environment.

https://vet-advantage.com/vet_advantage/improved-calf-health-benefits-long-term-performance/

https://bloximages.chicago2.vip.townnews.com/agupdate.com/content/tncms/assets/v3/editorial/f/88/f88f3b45-67bd-5bff-aa15-232e05789fe5/5f7765c2b9341.pdf.pdf

by Grace Stroud

Congratulations! The next generation of your dairy has just arrived. What can we do to make sure they get a great start to a long, healthy, and productive life?

Whether you choose to allow the cow to lick her newborn or dry the calf with a towel, the calf needs stimulation to increase blood flow and get an appetite for colostrum. Cleaning the calf of the amniotic fluid will also prevent bacteria and debris in the bedding from sticking to their coat. One of the most important things to remember is that calves do not have much of an immune system at birth. That is why calf managers, veterinarians, and industry professionals like Calf-Tel stress cleanliness. The cleaner the calf and its surroundings, the healthier start the calf will have.

The calf should also have its navel dipped to eliminate the umbilical pathway for bacteria and be relocated to a clean location with minimal distractions. Having fewer distractions will reduce the calf’s stress and be beneficial as you feed colostrum.

The next step is to administer colostrum. This should be done within the first one to two hours of birth. The sooner, the better. Keywords to remember in colostrum management are: “quality, quantity, and quickness”.  The longer the calf goes without colostrum, the guts’ ability to absorb the IgGs decreases. IgGs, or immunoglobins, transfer some of the mother’s immunity to the calf to help the calf build its immune system (Lopez et al., 2022).  To help determine the quality of your colostrum, an optical Brix refractometer or a digital Brix refractometer work well on the farm. A Brix value of 22% needs to be the cut-off. Anything lower than that should be discarded, and anything higher than 22% can be fed or frozen for storage (Life Start, n.d.). The calf should drink at least a gallon of colostrum. Working with your vet, you can create a colostrum management plan that will work for you and your farm.

Calf-Tel’s Starter Series comes with customizable accessories to adapt to your operation. The series comes with an optional steel base, which can be fitted with legs or wheels for ease of calf movement or simply rearranging. Placing this series on the ground can help you take advantage of any heated flooring you may have, while the optional base will hold the calves slightly above the ground and help with liquid drainage from the starter system.  Other accessories include chute or wire style bottle holders, and direct attach pails for water and calf starter. The Starter Series is easy to clean and sanitize, for safe and continued reuse, providing the perfect start for your youngest herd members.

Grace grew up with dairy, spending many days on the farm shadowing her dad as a herd manager. She quickly grew an appreciation and an attachment to the dairy industry, leading her to her career in ag sales and dairy farming today. Grace participated in 4-H for 10 years, competing in local, state, and national dairy judging; as well as local and state dairy quiz bowl competitions. Previously, Grace has worked in the milking parlor, with calves, and as an assistant herd manager. The assistant herd manager role included working with the dry cows, fresh cows, and any sick cows that needed special attention. Grace was also responsible for vaccinating all ages on the farm. Today, Grace enjoys raising calves, heifers, and preparing for local and national dairy shows when she is not in her office at Farmer Boy Ag.

If you have any questions or would like to contact Grace, please send all email inquiries to graces@farmerboyag.com.

SOURCES

Life Start. (n.d.). Measuring colostrum quality with a Brix refractometer is a practical method to ensure each calf gets good quality colostrum. Retrieved March 25, 2022, from https://ruminants.lifestartscience.com/colostrum-management/measuring-colostrum-quality-by-using-a-brix-refractometer

Lopez, A. J., & Heinrichs, A. J. (2022, January 27). Invited review: The importance of colostrum in the newborn dairy calf. Journal of Dairy Science. Retrieved March 25, 2022, from https://www.journalofdairyscience.org/article/S0022-0302(22)00037-6/fulltext

by Kelly Driver, MBA

Yes, I know it’s only April and, in many regions, there may still be some snow on the ground. But this is exactly when we need to begin thinking about a fly control plan for calves, before the temperature gets much warmer.

Choose Your Methods. Using an integrated pest management (IPM) system approach to fly control is often more effective than a single strategy. Integrated Pest Management is an effective, environmentally and cost sensitive approach to pest management that relies on a combination of common-sense practices, along with complete information on the life cycles of pests and their interaction with the environment.

The parts of an IPM program are:

1. Cultural control – practice good sanitation.

2. Biological control – parasitoid releases that help reduce the number of hatching flies.

3. Chemical control – sprays, larvicides, and residual premise & whole animal sprays.

Experience around dairy farms has shown that an effective IPM program for fly control often includes a combination of all three parts.

The First Step. Identifying the type of flies and pests on your farm is the first step in an effective control program. We have to know what we are dealing with to be able to treat the problem. To identify the types of flies, consider hanging sticky tapes or ribbons to trap them. The Internet, gardening magazines, or local experts may be helpful in accurately identifying the pests. I like to think of it like going to the doctor to identify if you have a viral or bacterial infection, in order to best treat the problem.

Cultural Control. Preventing fly populations from becoming a problem should be the number one priority of any pest management program and the single most important step on a dairy or calf operation is waste management. Removing piled manure, waste feed, and even the wet waste that can accumulate around the base of waterers should be a regular part of the weekly farm chore routine. Immature flies love to live in this type of moist waste and if the temperature is right, they will hatch in 10-21 days. Cleaning up and removing waste interrupts the fly life-cycle and helps reduce the population.

Another area that can be a great hiding place for flies is tall grasses and weeds. Keeping areas like this near hutch pads or the perimeter of calf barns trimmed throughout the season makes one less place for flies to live.

Biological Control. Fly parasites can be considered an effective natural biological control because they are a natural enemy that kills developing flies in the immature maggot and pupa stage. These parasites are gnat-sized, burrowing insects that are a naturally occurring enemy of all manure breeding pest flies. These tiny wasps are specific to flies and stay close to manure and areas where flies like to reproduce. The wasps are naturally nocturnal, have no ability to sting, and disregard humans or animals in the area. Because fly parasites reproduce in 2-3 weeks, they are constantly replenishing the beneficial insect population as the warmer, damp seasons progress. However, because the fly life cycle is much shorter than that of the parasite, it is important to start using the parasites early in the spring season.

John & Lynda Lehr had seen testimonials of other farms using fly parasites successfully and began to look into it further. They have been using fly parasites at their New York operation the past four years and have found that starting early is the real key to effectively managing flies. They are on an automatic delivery system with Spalding Fly Predators™ that begins in late April and continues until October. Their goal is always to be ahead of the fly development. In the peak summer months, new fly parasites are dispersed more often, but the Lehrs find it averaging every 2-3 weeks.

When the Lehrs began looking into fly parasites “we found good information on websites, but actually talking to the customer service reps by phone was most helpful for us,” they note. “The representatives really helped us determine a schedule and the number of Fly Predators^R we needed for our operation.” The team put parasites around waterers, barns, calf hutches and any wet or manure areas and have found that it has really helped manage their fly populations in conjunction with the pour-on and feed-through measures they were already using. Both their milk replacer and calf grain have Clarifly^R in them during the summer months. The Lehrs also use a pour-on fly repellant for heifers on pasture, but since adding the Fly Predators^R, find they only need to use it 2-3 times during the summer, instead of every two weeks as they did previously.

Another biological control method often considered on calf rearing sites is Clarifly^R, the feed through fly control the Lehrs mention. This product stops flies in the larval stage and can be included in both milk based and calf starter portions of the calf’s diet.

Chemical Control. As you develop your fly control plan for this season, it may also include some chemical control measures as well. These may be residual premise sprays, larvicides, and pour-on or sprays applied to the animals directly. Once again, when considering a product, it is best to select one that best aligns with the type of flies on your calf-rearing site.

Spring is in the air. As I write this, the first spring flowers are starting to appear from the ground and as the temperatures continue to warm, the pesky flies won’t be far behind. Now is the best time to develop a robust pest management plan for your farm. Start now to tell flies to “buzz off” this season.

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.

Courtesy of our dealer –

CRI REPRODUCCIÓN ANIMAL

MÉXICO SA DE CV

by Kelly Driver, MBA

Yes, dairy calves are affected by their own bovine-specific strain of coronavirus. This sickness can be a
significant cause of diarrhea (calf scours). Calf caregivers have been treating it for many years before the
novel coronavirus that causes COVID-19 emerged on the scene worldwide.

Is There a Connection?

In short, beyond the name, there is very little in common between the two strains because there are
many different versions of human and animal coronaviruses throughout the world. Each different
version of coronavirus has a very specific molecular makeup of the “spikes” on its surface. In order to
cause infection, these specific spike molecules must be able to attach to corresponding specific
molecules on a body cell, according to Dr. Russ Daly, South Dakota State University Extension
Veterinarian and Professor.

He further explains “pig cells have different surface molecules than do calf cells, than do human cells,
and so on. Additionally, respiratory cells have different surface molecules than do intestinal cells” (Daly,
2020). Calf caregivers may recall hearing about cats diagnosed with Feline Infectious Peritonitis (FIP) or
swine producers struggling with Porcine Epidemic Diarrhea (PED). These are all different forms of
coronaviruses (Daly, 2020).

Calf Scours

Scours is a term that the cattle industry has long used to refer to diarrhea in young calves. 95% of
infectious calf scours in calves under three weeks of age are caused by coronavirus, rotavirus or
Cryptosporidium (U of MN). All calves are exposed to these pathogens starting the very moment they
are born in the calving area. Whether a calf gets sick or not often depends on how much of the
pathogen the calf receives. The higher the dose of pathogen, the greater the risk of calf scours. So, let’s
take a quick look at the University of Minnesota’s description of these three contaminants:

-Rotavirus infects cells essential to the absorption of nutrients in the small intestine. The lack of small
intestine nutrient absorption causes nutritional deficiencies for the calf and interferes with the rest of
the digestive tract’s ability to absorb water. The result is diarrhea, with an added complication of
missing nutrients for the calf.

-Coronavirus infects cells in a similar way to rotavirus. However, instead of just interfering with
absorption, the virus actively kills cells in the lining of the intestine. The result is widespread destruction
of the lining of the small intestine. The calf cannot absorb any nutrients, the inflammation is massive,
and severe diarrhea occurs.

–Cryptosporidium, often referred to as ‘Crypto’, is a protozoan (a microscopic animal). The most
important thing to remember is that Crypto is not bacteria. Crypto implants itself in the wall of the
intestine and causes severe inflammatory damage to the lining of the intestine. This damage results in
diarrhea for the calf. Crypto infections are incredibly painful for the calf. Outside of the body, crypto has
a thick shell that allows it to survive for long periods in the environment (Source: University of Minnesota Extension).

Since Cryptosporidium was addressed in a previous Calf Corner blog, we will continue to
focus on the corona & rota viruses.

Rotaviruses are the most common cause of diarrhea in young calves, typically from 5-21 days of age.
Pale yellow diarrhea is common, and calf caregivers may also observe blood specks and mucus in the
feces. Affected calves are often lethargic, reluctant to drink, and have dull eyes.

One of the big challenges with rota and corona viruses is as the calves become dehydrated, they become
more susceptible to secondary infections.

Diagnosis

Proper diagnosis to determine the cause of calf diarrhea should be done with your herd veterinarian.
This may include fecal sampling at a diagnostic laboratory.

Treatment

Oral fluids are the most important treatment that should be started at the first signs of diarrhea to help
prevent the dehydration that ultimately kills calves. Allowing calves to drink the electrolytes themselves
is preferred, as oral fluids delivered by stomach tube may have delayed absorption because they are
deposited in the rumen. If the calf is already quite dehydrated, intravenous fluids should be given.
Please do NOT stop feeding milk to these calves. They need all the nutritional value they can get from
the milk to help fight off disease.

Scours is quite uncomfortable and painful for calves. Work with your veterinary to provide an approved
anti-inflammatory for pain relief as needed in your calf management protocol.

Taking the calf’s rectal temperature should be a standard part of any health assessment. Antibiotics are
another tool that should be addressed in calf protocols. Remember that 95% of calf scours under 3
weeks of age are caused by viruses and protozoans, not bacteria, rendering ineffective to treat the cause
of the disease. Therefore, antibiotics would normally be reserved for cases when the calf’s temperature
is outside normal range of 101-102.5 degrees Fahrenheit (U of MN).

Prevention

Prevention of calf scours all together is the real key.

Starting early with a solid vaccination program administered to a healthy cow helps to boost the
antibodies available to the calf in the four quarts of colostrum it should be fed within the first two hours
of life. Vaccines given at the correct times while the calf is still in utero can also target scours-causing
agents. There are also some products available that can reduce scours when given at birth to the calf.
The herd veterinarian can help develop a robust vaccination program tailored to each specific herd
situation.

I can’t emphasize how important it is that everything the newborn calf has contact with should be very
clean. From their arrival in a very clean, well-bedded calving area to well-managed, high-quality
colostrum that is low in bacteria, to properly clean and sanitized feeding equipment and housing, try to
look at every item your calves will come in contact with. The more pathogens that can be removed
through proper cleaning, the more we set our calves up for success.

Another key in calf success is proper nutrition. Calves need a minimum of 8 quarts of either whole milk
or high-quality milk replacer each day to meet their maintenance and growth needs. Their need for
additional energy and nutrition increases anytime the temperature is outside their thermal neutral zone,
particularly when it is colder. (We can help keep calves warmer with a properly fitted calf jacket that
contains a true insulating material, like ThinsulateTM.) Delivering calves ample nutrition with a consistent
temperature, total solids level and on a routine time schedule also aids in prevention.

Housing units, whether individual or group, should be cleaned and disinfected between each use. Calf-Tel offers many plastic feeding and housing options that are designed for easy clean up and can be
viewed at Calf-Tel.com.

All of these factors can be combined to best prevent calf scours. Remember that rotaviruses,
coronaviruses and Cryptosporidium naturally exist on dairy farms. It is our job as the calf caregivers to
limit each newborn calf’s exposure level to these threats. Using a farm-wide approach that includes total
herd health under supervision from a veterinarian, high-quality colostrum management and calf
nutrition, and cleaning and sanitizing all feeding equipment and housing areas gives the best chance of
limiting calf scours events.

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.

Sources:
Armstrong, Joe, DVM. (2019). Causes and prevention of dairy calf scours. University of Minnesota
Extension. Retrieved from Causes and prevention of dairy calf scours | UMN Extension.

Daly, Russ. (2020, September 9). COVID-19 and Livestock: Is there a connection? South Dakota State
University Extension. Retrieved from COVID-19 and Livestock: Is there a connection? (sdstate.edu).

Keha A, Xue L, Yan S, Yue H, Tang C. Prevalence of a novel bovine coronavirus strain with a recombinant
hemagglutinin/esterase gene in dairy calves in China. Transbound Emerg Dis. 2019 Sep;66(5):1971-1981.
doi: 10.1111/tbed.13228. Epub 2019 May 31. PMID: 31077561; PMCID: PMC7168545.

by Kelly Driver, MBA

Yes, dairy calves are affected by their own bovine-specific strain of coronavirus. This sickness can be a
significant cause of diarrhea (calf scours). Calf caregivers have been treating it for many years before the
novel coronavirus that causes COVID-19 emerged on the scene worldwide.

Is There a Connection?

In short, beyond the name, there is very little in common between the two strains because there are
many different versions of human and animal coronaviruses throughout the world. Each different
version of coronavirus has a very specific molecular makeup of the “spikes” on its surface. In order to
cause infection, these specific spike molecules must be able to attach to corresponding specific
molecules on a body cell, according to Dr. Russ Daly, South Dakota State University Extension
Veterinarian and Professor.

He further explains “pig cells have different surface molecules than do calf cells, than do human cells,
and so on. Additionally, respiratory cells have different surface molecules than do intestinal cells” (Daly,
2020). Calf caregivers may recall hearing about cats diagnosed with Feline Infectious Peritonitis (FIP) or
swine producers struggling with Porcine Epidemic Diarrhea (PED). These are all different forms of
coronaviruses (Daly, 2020).

Calf Scours

Scours is a term that the cattle industry has long used to refer to diarrhea in young calves. 95% of
infectious calf scours in calves under three weeks of age are caused by coronavirus, rotavirus or
Cryptosporidium (U of MN). All calves are exposed to these pathogens starting the very moment they
are born in the calving area. Whether a calf gets sick or not often depends on how much of the
pathogen the calf receives. The higher the dose of pathogen, the greater the risk of calf scours. So, let’s
take a quick look at the University of Minnesota’s description of these three contaminants:

-Rotavirus infects cells essential to the absorption of nutrients in the small intestine. The lack of small
intestine nutrient absorption causes nutritional deficiencies for the calf and interferes with the rest of
the digestive tract’s ability to absorb water. The result is diarrhea, with an added complication of
missing nutrients for the calf.

-Coronavirus infects cells in a similar way to rotavirus. However, instead of just interfering with
absorption, the virus actively kills cells in the lining of the intestine. The result is widespread destruction
of the lining of the small intestine. The calf cannot absorb any nutrients, the inflammation is massive,
and severe diarrhea occurs.

–Cryptosporidium, often referred to as ‘Crypto’, is a protozoan (a microscopic animal). The most
important thing to remember is that Crypto is not bacteria. Crypto implants itself in the wall of the
intestine and causes severe inflammatory damage to the lining of the intestine. This damage results in
diarrhea for the calf. Crypto infections are incredibly painful for the calf. Outside of the body, crypto has
a thick shell that allows it to survive for long periods in the environment (Source: University of Minnesota Extension).

Since Cryptosporidium was addressed in a previous Calf Corner blog, we will continue to
focus on the corona & rota viruses.

Rotaviruses are the most common cause of diarrhea in young calves, typically from 5-21 days of age.
Pale yellow diarrhea is common, and calf caregivers may also observe blood specks and mucus in the
feces. Affected calves are often lethargic, reluctant to drink, and have dull eyes.

One of the big challenges with rota and corona viruses is as the calves become dehydrated, they become
more susceptible to secondary infections.

Diagnosis

Proper diagnosis to determine the cause of calf diarrhea should be done with your herd veterinarian.
This may include fecal sampling at a diagnostic laboratory.

Treatment

Oral fluids are the most important treatment that should be started at the first signs of diarrhea to help
prevent the dehydration that ultimately kills calves. Allowing calves to drink the electrolytes themselves
is preferred, as oral fluids delivered by stomach tube may have delayed absorption because they are
deposited in the rumen. If the calf is already quite dehydrated, intravenous fluids should be given.
Please do NOT stop feeding milk to these calves. They need all the nutritional value they can get from
the milk to help fight off disease.

Scours is quite uncomfortable and painful for calves. Work with your veterinary to provide an approved
anti-inflammatory for pain relief as needed in your calf management protocol.

Taking the calf’s rectal temperature should be a standard part of any health assessment. Antibiotics are
another tool that should be addressed in calf protocols. Remember that 95% of calf scours under 3
weeks of age are caused by viruses and protozoans, not bacteria, rendering ineffective to treat the cause
of the disease. Therefore, antibiotics would normally be reserved for cases when the calf’s temperature
is outside normal range of 101-102.5 degrees Fahrenheit (U of MN).

Prevention

Prevention of calf scours all together is the real key.

Starting early with a solid vaccination program administered to a healthy cow helps to boost the
antibodies available to the calf in the four quarts of colostrum it should be fed within the first two hours
of life. Vaccines given at the correct times while the calf is still in utero can also target scours-causing
agents. There are also some products available that can reduce scours when given at birth to the calf.
The herd veterinarian can help develop a robust vaccination program tailored to each specific herd
situation.

I can’t emphasize how important it is that everything the newborn calf has contact with should be very
clean. From their arrival in a very clean, well-bedded calving area to well-managed, high-quality
colostrum that is low in bacteria, to properly clean and sanitized feeding equipment and housing, try to
look at every item your calves will come in contact with. The more pathogens that can be removed
through proper cleaning, the more we set our calves up for success.

Another key in calf success is proper nutrition. Calves need a minimum of 8 quarts of either whole milk
or high-quality milk replacer each day to meet their maintenance and growth needs. Their need for
additional energy and nutrition increases anytime the temperature is outside their thermal neutral zone,
particularly when it is colder. (We can help keep calves warmer with a properly fitted calf jacket that
contains a true insulating material, like ThinsulateTM.) Delivering calves ample nutrition with a consistent
temperature, total solids level and on a routine time schedule also aids in prevention.

Housing units, whether individual or group, should be cleaned and disinfected between each use. Calf-Tel offers many plastic feeding and housing options that are designed for easy clean up and can be
viewed at Calf-Tel.com.

All of these factors can be combined to best prevent calf scours. Remember that rotaviruses,
coronaviruses and Cryptosporidium naturally exist on dairy farms. It is our job as the calf caregivers to
limit each newborn calf’s exposure level to these threats. Using a farm-wide approach that includes total
herd health under supervision from a veterinarian, high-quality colostrum management and calf
nutrition, and cleaning and sanitizing all feeding equipment and housing areas gives the best chance of
limiting calf scours events.

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.

Sources:
Armstrong, Joe, DVM. (2019). Causes and prevention of dairy calf scours. University of Minnesota
Extension. Retrieved from Causes and prevention of dairy calf scours | UMN Extension.

Daly, Russ. (2020, September 9). COVID-19 and Livestock: Is there a connection? South Dakota State
University Extension. Retrieved from COVID-19 and Livestock: Is there a connection? (sdstate.edu).

Keha A, Xue L, Yan S, Yue H, Tang C. Prevalence of a novel bovine coronavirus strain with a recombinant
hemagglutinin/esterase gene in dairy calves in China. Transbound Emerg Dis. 2019 Sep;66(5):1971-1981.
doi: 10.1111/tbed.13228. Epub 2019 May 31. PMID: 31077561; PMCID: PMC7168545.

Courtesy of our dealer –
CRI REPRODUCCIÓN ANIMAL
MÉXICO SA DE CV.

by Kelly Driver, MBA

Assuring that we are giving every calf the best opportunity for excellent health and growth is the shared goal of calf care teams around the world. But the challenges presented to those teams are often surrounded by some “dirty” words or biological challenges that exist on nearly every dairy farm. Let’s take a look at some of the more frequent challenges.

Organic matter is a natural concern in calf care as it harbors bacteria and parasites, as well as provides a breeding ground for these organisms. Organic matter is defined as compounds that have come from the remains of organisms such as plants and animals and their waste products. In terms of calf raising, we immediately think about manure, milk, and feed deposits on surfaces in the calf’s environment, beginning at birth.

Biofilms are a layer of organic material, including fats and proteins, that stick to any surface and are so thin that they cannot be seen or felt. However, if they are left to grow on calf feeding equipment, we may eventually see a yellowish or tan-colored film that can be scraped with our fingernail. The surface may even develop a slimy feel. Biofilms provide a great place for bacteria to grow and each time the piece of equipment or calf housing is used, the resident bacteria are there to contaminate the calf. When calves are exposed to low levels of bacteria repeatedly, it can lead to a scours problem. Bacteria associated with respiratory disease, scours, roto virus and crypto thrive on biofilms. This is why it is so important to use equipment that can actually be easily cleaned, like plastic pens or hutches from Calf-Tel.

Cryptosporidium parvum is one of the most common parasites in dairy facilities. It most often shows up in calves between 7 to 28 days of age and initially presents as lethargic, weak calves. Crypto is a protozoan parasite that at one stage of its life cycle forms egg-like bodies called oocysts, which contaminate everything they come in contact with – bedding, feed, water, and the hands and clothes of the calf raiser. Once the crypto organisms are ingested by a calf, they destroy the inner lining of the large intestine. This allows milk to pass through nearly undigested and the resulting diarrhea will typically be a yellowish to white color and may appear foamy or contain blood, mucus or bile.

Cryptosporidium oocysts thrive in wet environments, like wet bedding and calving areas. The oocysts can live for up to a year in cool moist conditions and are resistant to drying and freezing. The parasite normally exists on most, if not all, dairy farms where calves are raised. Diligent attention and sanitation of the calving area and clean, dry, sanitized plastic calf housing and feed equipment can help to minimize the risk of infection. Mortality is generally low with c. parvum, but morbidity is high and the calves will have a slower growth rate than unaffected calves.  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.

Bacteria load can be easily measured by testing equipment used every day on farm for feeding, transporting and housing newborn calves. It is easy to check ourselves for cleanliness using an ATP meter and swabs that measure bacteria loads. The goal is a score under 100 and a reading under 10 is exceptional. If your farm does not have a meter, consult with your herd veterinarian.

Here are a couple examples of areas to check:

Ammonia gas is very harmful for a calf’s natural defense system in the trachea. Many positive conditions exist in calf housing for the microbial activity that releases ammonia gas. Urine provides both nutrients and liquid, the bedding material often provides a favorable pH environment, and calves warm the soiled bedding when resting.

Tiny hair-like fingers or cilia line the trachea, working to push foreign materials that the calf has inhaled up and out of the trachea. These cilia work in a wave action and serve as a defense system against respiratory infections. But persistent exposure to relatively low ammonia levels, which disrupts the wave pattern of the cilia leaves calves at a higher risk for bacterial respiratory illness. Slowing down ammonia causing bacteria is as simple as clean dry bedding in well-drained calf housing areas.  If you unsure if your calf bedding is dry enough, kneel in the bed for one minute, if your knees get wet, it is not dry enough to slow down ammonia production and help protect calves from respiratory disease.

Coccidiosis is a digestive disease in dairy calves and heifers that is most often found from 1 month to 1 year of age. The protozoa can be prolific in facilities with poor cleanliness, use of bedded pack management, or inconsistent feeding additive (coccidiostat) usage across pens. The Eimeria protozoa starts off similar to other digestive parasites with the animal consuming the protozoa egg or oocyst.  This consumption takes place by various routes including eating contaminated feed, bedding or water; grooming themselves or other animals; or licking their contaminated surroundings (walls, gates, feeders, etc.), according to Dr. Matt Akins at University of Wisconsin at Madison.  The oocyst has a very protective outer wall that resists breakdown from chemical and physical action, and can be viable in a moist, warm environment for several months to years. Similar to other diseases, maintaining heifers in similar age groups, using all in/all out management, and cleaning of pens/feeders/waterers between moves can help reduce pathogen loads.  In addition to maintaining a clean environment, most operations use a coccidiostat in their feed mix to control the protozoa in the heifer’s digestive tract. This allows the heifer to develop immunity to the protozoa while controlling protozoal levels to minimize coccidiosis, according to Dr. Akins.

Flies. Stable flies, house flies, and blow flies are the most common types found around dairies. They are labeled “filth flies” because they prefer moist conditions and like to lay their eggs in manure, decaying organic matter, spilled or spoiled feedstuffs, and damp bedding. Other common flies that are more often found in pastures or open areas can include horse flies, deer flies, face flies, horn flies, and even mosquitoes. Several of these pests are biting flies that require a “blood meal” and can be quite disturbing to calves.

It is important to develop an integrated pest management plan (IPM) to maximize fly control efforts at your operation, focusing on three key areas:

1. Sanitation
2. Biological control
3. Chemical control

Both house and stable flies breed in manure, decaying silage, and moist bedding or feedstuffs, making sanitation the key management practice to minimizing the population. Since the house fly life cycle is just 10 days, cleaning everything possible weekly is most desirable and removing any spilled or leftover feeds daily is also helpful.

Another important sanitation measure is keeping the bedding in the calf housing area dry. Some farms switch to sand, wood shavings or sawdust as bedding material instead of straw in the warmer months of the year. Opening rear doors and vents on Calf-Tel hutches or pens to encourage airflow will also help keep the bedding dry.

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.

Recommended Steps for Cleaning Calf Contact Surfaces:

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 germicides are the same. It is important to test your germicide regularly with an approved method for the specific product you are using to ensure you have the germicidal killing power needed to achieve your calf hygiene goals, whether applying it by brush, spray or foaming action.

(Source: James Umphrey, Regional Sanitation Advisor for ABS Global Inc.)

Hygiene is always a critical piece in the puzzle of maintaining healthy calves. Keeping calf care utensils and equipment clean is critically important to assuring the health of the youngest herd members. At Calf-Tel, we are passionate about helping assure calves a successful start. You can learn more about these “dirty words” and others in Calf-Tel’s Calf Corner!

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, MBA

Assuring that we are giving every calf the best opportunity for excellent health and growth is the shared goal of calf care teams around the world. But the challenges presented to those teams are often surrounded by some “dirty” words or biological challenges that exist on nearly every dairy farm. Let’s take a look at some of the more frequent challenges.

Organic matter is a natural concern in calf care as it harbors bacteria and parasites, as well as provides a breeding ground for these organisms. Organic matter is defined as compounds that have come from the remains of organisms such as plants and animals and their waste products. In terms of calf raising, we immediately think about manure, milk, and feed deposits on surfaces in the calf’s environment, beginning at birth.

Biofilms are a layer of organic material, including fats and proteins, that stick to any surface and are so thin that they cannot be seen or felt. However, if they are left to grow on calf feeding equipment, we may eventually see a yellowish or tan-colored film that can be scraped with our fingernail. The surface may even develop a slimy feel. Biofilms provide a great place for bacteria to grow and each time the piece of equipment or calf housing is used, the resident bacteria are there to contaminate the calf. When calves are exposed to low levels of bacteria repeatedly, it can lead to a scours problem. Bacteria associated with respiratory disease, scours, roto virus and crypto thrive on biofilms. This is why it is so important to use equipment that can actually be easily cleaned, like plastic pens or hutches from Calf-Tel.

Cryptosporidium parvum is one of the most common parasites in dairy facilities. It most often shows up in calves between 7 to 28 days of age and initially presents as lethargic, weak calves. Crypto is a protozoan parasite that at one stage of its life cycle forms egg-like bodies called oocysts, which contaminate everything they come in contact with – bedding, feed, water, and the hands and clothes of the calf raiser. Once the crypto organisms are ingested by a calf, they destroy the inner lining of the large intestine. This allows milk to pass through nearly undigested and the resulting diarrhea will typically be a yellowish to white color and may appear foamy or contain blood, mucus or bile.

Cryptosporidium oocysts thrive in wet environments, like wet bedding and calving areas. The oocysts can live for up to a year in cool moist conditions and are resistant to drying and freezing. The parasite normally exists on most, if not all, dairy farms where calves are raised. Diligent attention and sanitation of the calving area and clean, dry, sanitized plastic calf housing and feed equipment can help to minimize the risk of infection. Mortality is generally low with c. parvum, but morbidity is high and the calves will have a slower growth rate than unaffected calves.  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.

Bacteria load can be easily measured by testing equipment used every day on farm for feeding, transporting and housing newborn calves. It is easy to check ourselves for cleanliness using an ATP meter and swabs that measure bacteria loads. The goal is a score under 100 and a reading under 10 is exceptional. If your farm does not have a meter, consult with your herd veterinarian.

Here are a couple examples of areas to check:

Ammonia gas is very harmful for a calf’s natural defense system in the trachea. Many positive conditions exist in calf housing for the microbial activity that releases ammonia gas. Urine provides both nutrients and liquid, the bedding material often provides a favorable pH environment, and calves warm the soiled bedding when resting.

Tiny hair-like fingers or cilia line the trachea, working to push foreign materials that the calf has inhaled up and out of the trachea. These cilia work in a wave action and serve as a defense system against respiratory infections. But persistent exposure to relatively low ammonia levels, which disrupts the wave pattern of the cilia leaves calves at a higher risk for bacterial respiratory illness. Slowing down ammonia causing bacteria is as simple as clean dry bedding in well-drained calf housing areas.  If you unsure if your calf bedding is dry enough, kneel in the bed for one minute, if your knees get wet, it is not dry enough to slow down ammonia production and help protect calves from respiratory disease.

Coccidiosis is a digestive disease in dairy calves and heifers that is most often found from 1 month to 1 year of age. The protozoa can be prolific in facilities with poor cleanliness, use of bedded pack management, or inconsistent feeding additive (coccidiostat) usage across pens. The Eimeria protozoa starts off similar to other digestive parasites with the animal consuming the protozoa egg or oocyst.  This consumption takes place by various routes including eating contaminated feed, bedding or water; grooming themselves or other animals; or licking their contaminated surroundings (walls, gates, feeders, etc.), according to Dr. Matt Akins at University of Wisconsin at Madison.  The oocyst has a very protective outer wall that resists breakdown from chemical and physical action, and can be viable in a moist, warm environment for several months to years. Similar to other diseases, maintaining heifers in similar age groups, using all in/all out management, and cleaning of pens/feeders/waterers between moves can help reduce pathogen loads.  In addition to maintaining a clean environment, most operations use a coccidiostat in their feed mix to control the protozoa in the heifer’s digestive tract. This allows the heifer to develop immunity to the protozoa while controlling protozoal levels to minimize coccidiosis, according to Dr. Akins.

Flies. Stable flies, house flies, and blow flies are the most common types found around dairies. They are labeled “filth flies” because they prefer moist conditions and like to lay their eggs in manure, decaying organic matter, spilled or spoiled feedstuffs, and damp bedding. Other common flies that are more often found in pastures or open areas can include horse flies, deer flies, face flies, horn flies, and even mosquitoes. Several of these pests are biting flies that require a “blood meal” and can be quite disturbing to calves.

It is important to develop an integrated pest management plan (IPM) to maximize fly control efforts at your operation, focusing on three key areas:

1. Sanitation
2. Biological control
3. Chemical control

Both house and stable flies breed in manure, decaying silage, and moist bedding or feedstuffs, making sanitation the key management practice to minimizing the population. Since the house fly life cycle is just 10 days, cleaning everything possible weekly is most desirable and removing any spilled or leftover feeds daily is also helpful.

Another important sanitation measure is keeping the bedding in the calf housing area dry. Some farms switch to sand, wood shavings or sawdust as bedding material instead of straw in the warmer months of the year. Opening rear doors and vents on Calf-Tel hutches or pens to encourage airflow will also help keep the bedding dry.

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.

Recommended Steps for Cleaning Calf Contact Surfaces:

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 germicides are the same. It is important to test your germicide regularly with an approved method for the specific product you are using to ensure you have the germicidal killing power needed to achieve your calf hygiene goals, whether applying it by brush, spray or foaming action.

(Source: James Umphrey, Regional Sanitation Advisor for ABS Global Inc.)

Hygiene is always a critical piece in the puzzle of maintaining healthy calves. Keeping calf care utensils and equipment clean is critically important to assuring the health of the youngest herd members. At Calf-Tel, we are passionate about helping assure calves a successful start. You can learn more about these “dirty words” and others in Calf-Tel’s Calf Corner!

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.

Courtesy of our dealer –
CRI REPRODUCCIÓN ANIMAL
MÉXICO SA DE CV.

By Lindsay Ferlito & Casey Havekes, Cornell Cooperative Extension North Country Regional Ag Team

Over the past year and a half, we’ve received several requests for calf barn ventilation support. Some of the most popular questions have been, “I’m thinking about building a new calf barn. What ventilation system works best?” Or, “I just built this calf barn but I’m having a ton of respiratory challenges. What is going on?” And last, “How can I retrofit this old facility to provide better ventilation for my calves?”

The simple yet complex response to all of these questions is that there is no ‘one size fits all’ approach. Unfortunately, due to the complexity of prevailing winds, the direction of barns, wind shadows, mechanics, and a variety of other variables, there are so many different moving parts when it comes to calf barn ventilation.

To begin addressing the incoming questions, we designed an exploratory research project that aimed to investigate a variety of different calf barn housing and ventilation systems across Northern New York. This research project was funded by the Northern New York Agricultural Development Program. One of the study objectives was to evaluate air flow and air exchanges through ‘fogging’ the facilities. The study enrolled 15 calf barns across northern NY. Many others have reached out through word of mouth and because of our outreach efforts. To try to capture some of the complexity and uniqueness of each calf barn, we compiled 5 of the most interesting case studies that arose because of our study and further troubleshooting efforts. The assessments and solutions described in this article are the result of a collaboration between participating farms, herd veterinarians, Cornell Cooperative Extension Dairy Specialists, Lindsay Ferlito and Casey Havekes, and PRO-DAIRY Strategic Farm Planning Specialist, Tim Terry.

We also noticed that the bins holding the acidified milk were blocking some of the air movement across the pen from the fans. This resulted in dead spots and pooling directly surrounding the feeding bins.

Solution: We came up with two potential solutions for this facility. One option involves removing the fans from the side wall and installing new fans in two rows about the calves (one row on each side of the center feed alley). The other option involves closing the overhead doors and cross-ventilating by adding a bank of fans to the side walls. A concern with the latter option is that the bins holding the acidified milk will block too much of the air and consequently the air quality will be poorer directly behind this area. The farm owners are still working through these action plans to assess which option will work best for them.

Case Study #2

Facility Description: Calves are group housed and fed with automated feeders. There is one tube above the calves.

Problem: The farm owner mentioned a high number of respiratory cases. Additionally, as you can see in Figure 2, there is bird netting below the tube which is potentially impairing air flow.

Unless precipitation is entering the building or bedding is being blown off the pack, the curtains should remain open. If these recommendations do not improve ventilation during the summer months, we suggest considering adding two summer positive pressure tubes to supplement the natural ventilation.

Case Study #3

Facility Description: Group housed calves fed ad libitum acidified milk. There are several tubes above the calves, and curtains on the side walls.

Problem: Farm owner has observed high respiratory issues and high treatment rates. One of the side walls also requires maintenance and as a result the curtain must stay up on that side of the barn to prevent calves from getting loose. Several of the tubes also require maintenance and are not functioning.

Solution: We recommend the farm fixes the side wall so the curtain can be lowered in order to achieve proper air exchanges in that section of the barn. We speculate they can get closer to the recommended 40-60 air exchanges/hour for summertime by having all the tubes running. As a result, we also recommended the broken tubes be fixed, and all tubes be cleaned so they can run as designed.

Assessment: The day of the assessment was hot and breezy. We fogged the barn once with the end doors open and then again with the end doors closed. When the end doors were open, the prevailing wind counteracted the air coming through the inlet holes and basically pushed it back out through the open curtains. As a result, it was obvious that the fog did not move properly across the pens. When we fogged the barn with the end door closed, air movement was better. However, there was still dead spots and inadequate air exchanges for summer.

Solution: We recommend installing more fans in the inlet side to help push more air through and increase air exchanges. We also recommend keeping the end doors closed so that the ventilation system can properly do its job without interference from prevailing winds.

Case Study #5

Facility Description: Calves are individually housed. The barn relies on natural ventilation. There are side wall curtains and 3 chimney exhaust fans.

Problem: Very high treatment rates and respiratory cases. There is also a second calf barn directly behind this barn that is used to house older, weaned calves. This barn creates a wind shadow for the barn housing the younger animals. The barn prevents fresh air from getting to the calves. This area also gets very cold in the winter making it especially difficult to ventilate it appropriately.

Assessment: The day of the assessment was a cool, breezy, fall day. Ventilation felt adequate, although we previously went on a very hot, summer day and felt that there was little to no air movement. Our assessment discovered winter ventilation is likely adequate, however, there is not sufficient air flow coming into the barn to meet summer ventilation requirements. This is largely influenced by the new barn creating a wind shadow and preventing air flow into the barn.

Also, the cropping rotation will have to consider physically smaller crops in the adjacent field. Larger crops plus the existing knoll upwind from the facility creates a wind shadow.

Conclusion

There are so many factors to consider when troubleshooting calf ventilation systems. Here are a few important takeaways from previous research and our case studies:

1. Summer Ventilation requires 40-60 air exchanges per hour and winter ventilation requires 4 air exchanges per hour.
2. Naturally, we want to open everything up on hot summer days. However, it may not be the best idea if you’re ventilation system is designed to have the barn closed up.
3. Air will always take the path of least resistance. Keep this in mind if you have structures and equipment in the barn that could impede air flow.

Finally, you don’t have to tackle calf barn ventilation alone. Regardless of where you are reading this from, reach out to your local Extension agents, your herd veterinarian, or a trusted calf advisor to get started if you need help troubleshooting your ventilation system.