Diseases in Dairy Calves

Diseases in Dairy Calves

By Heather Smith Thomas

There are many disease issues that can impact dairy calves. Multiple risk factors contribute to disease and these can vary from one farm to the next. For instance, some farms struggle with pneumonia in the first few weeks of life, others experience this issue after weaning, and some don’t see much pneunomia at all.

Dr. Peter Erickson, Extension Dairy Specialist, University of New Hampshire, says the first, most important thing is to calve in a really clean environment. “We used to say the best environment would be a nice clean pasture, but most dairies don’t have that opportunity,” he says.

Dairy cattle are more fragile than their beef cousins. “A beef cow might be able to calve in a snowdrift and the calf can be up and suckling, but that isn’t going to happen with a dairy cow and calf. They need more monitoring and care, and should calve in a really clean area,” says Erickson.

Robert Lynch, DVM, Dairy Herd Health & Management Specialist, Cornell University, says the highest risk calves are the very young. “The first problem we usually see is neonatal calf diarrhea, which can occur as early as day one. Respiratory issues can become an issue as they get a few days older, with exposure to bacterial and viral pathogens. We see more of that as they approach weaning age and even more after weaning,” says Lynch.

“It’s always more economical to prevent health problems than treat them. We need to lower all the contributing risks to illness,” Lynch says. Even if a calf is treated and recovers, there may be an adverse impact on her future production as a cow.

This is hard to analyze; many other things play a role in cow performance and can get in the way of that kind of research. “Maybe a calf has diarrhea and we medicate and rehydrate the calf and get her over the diarrhea. We think we’ve won, but if we follow this calf later in life she may not grow as well, leaving the herd early because of poor performance. If she does become a cow, she may not perform as well as cohorts that didn’t have diarrhea as a calf. Just because we get calves over their illness and they appear to have recovered doesn’t mean they didn’t suffer long-term damage,” he says.

They generally don’t meet their genetic potential. If a calf gets pneumonia, for instance, this can permanently damage the lungs. “When we ultrasound calves’ lungs after a respiratory insult there is often consolidation and some abscessed regions. There isn’t much extra lung space in cattle; if part of the lung is ruined, this can impair respiratory function for the rest of their life. This is apparent in hot weather when cattle rely on their lungs for cooling,” says Lynch.

IMPORTANCE OF COLOSTRUM

Timing of colostrum is crucial. Dr. Dean Elder, Attending Veterinarian at the University of New Hampshire, teaching Pre-Veterinary students, and Station Veterinarian for the two university dairies, says everyone realizes it is important for calves to receive colostrum within the first 1 to 2 hours of life, but this isn’t soon enough if calves are in a dirty environment. It’s a race between the pathogens and the antibodies, and the pathogens win if the calf doesn’t have colostrum almost immediately. “As soon as that calf hits the ground, it should receive colostrum. In large dairies it may be impossible to do, but you have to get colostrum into that calf well before 4 hours, and within the first 30 minutes is best,” Elder says.

“We also need to make sure the calf gets an adequate amount of good quality colostrum,” says Erickson. “The minimum for a dairy calf is 4 quarts, and new data is suggesting that 6 quarts is better and some people are giving 8 quarts. We need to make sure calves get a minimum of 4 quarts as soon as possible. For Holsteins, some people give a gallon all at once. Some people split it. If you give 6 quarts you need to get it into the calf before 8 to 12 hours of age—with the first gallon immediately. If the calf won’t drink it, you need to use a stomach tube,” he says.

Colostrum is essentially the calf’s first vaccination, providing immediate temporary protection against many pathogens. “The colostrum needs to be good. The easiest way to tell if it’s good is to use a refractometer. This tool may be digital or visual. I like the digital refractometer because it only takes a few drops of colostrum on the lens and it will give you a reading. Typically, we want about 22.5% Brix, which is analogous to 50 grams of IgG per liter or colostrum,” Erickson says.

Some cows don’t make good quality colostrum and if you harvest colostrum too late, it won’t be as good. Highest quality is right at calving. If the cow calves at 8 a.m. and you won’t be milking her until 5 p.m. in the afternoon, quality will be diminished because it is being diluted by regular milk,” he says.

Another problem people are discovering is that some cows don’t produce any colostrum at all. This was first noticed in Jerseys but it also happens in Holsteins. “Our data here, which included a herd from Idaho, showed that 25% of the Jerseys don’t produce enough colostrum to feed their calves. With Holsteins, a big study in New York State with 19,000 cows found about 12% of those cows produced no colostrum. They produce milk, but for some reason they are not producing colostrum and we are trying to figure out why. This means that farms should have a colostrum replacer product on hand. It has to be colostrum-based, from dehydrated colostrum.”

SCOURS

The most common issue in young calves is scours. In very young calves, diseases that cause diarrhea are more common than respiratory or other issues. “Depending on the age of the calf, the common causes of scours are bacterial, viral or parasites, like protozoa, that cause cryptosporidiosis, giardia or coccidiosis,” says Elder. Bacterial scours like E. coli can affect very young calves, 1 to 5 days of age.

“We can decrease the incidence of this problem with proper management—making sure calving pens are clean when calves are born and giving pregnant cows E. coli vaccines ahead of calving (so there will be antibodies in the colostrum),” Elder says. Some of the pre-calving vaccines also provide some protection against rotavirus and coronavirus.

If a calf doesn’t receive an adequate amount of colostrum soon after birth, it can’t receive the benefit from those antibodies. There are also rota-coronavirus vaccines that can be given to calves as soon as they are born. These must be given before colostrum, and within 30 minutes of calving. Rota and coronavirus infections can occur within the first week of life, so we want to prevent that. “There are also other products like Tri-Shield First Defense gel that contain antibodies to E. coli and rota-coronaviruses. We use that product a lot in our dairy calves,” says Elder.

A variety of products can be given to young calves to cut down on early life scours. This is important, since calves at that age are fragile and haven’t had a chance yet to develop their own immune system. They are very vulnerable to disease.

When calves are a bit older, they may develop parasitic scours. The life cycles of those protozoa take longer to damage the GI tract. The calf may be exposed to these pathogens soon after birth, but it takes longer for the protozoa to go through their life cycle within the intestines. The calf won’t break with scours until later. It takes at least 3 weeks (often 4 weeks) for coccidiosis, 5 to 30 days for giardia, and 7 to 12 days for cryptosporidiosis. If you see scours in the first 5 days of life, it’s not parasitic.

There is no effective medication to deal with cryptosporidiosis and this problem is still prevalent in the dairy industry. It can lie quietly within a herd–no animals showing signs–and then pop out. “Calves might seem to be fine and then all of a sudden farm workers may get sick with cryptosporidiosis, since this is a zoonotic disease that affects people. This is one of our main concerns for people working with calves,” says Elder.

Erickson says he got it when he was a kid, working on a dairy farm for 5 years. “There is really no treatment for this disease, other than supportive care and hydration, making sure the calf is in a clean environment and simply letting it run its course.”

Even if a farm worker is not seriously affected, he/she might take it home to his or her family. Children, older people and anyone with a compromised immune system may be at risk for serious illness. It’s usually a direct fecal-oral route, but if farm workers get calf feces on their hands, and don’t wash their hands before eating or handling things other people might handle, it could spread.

“It’s somewhat similar to the cyclospora disease outbreak with lettuce, causing intestinal illness in humans. That was caused by a different microscopic single-celled parasite. They are not the same, but they both cause terrible diarrhea and you don’t want to come down with crypto!” says Elder.

Coccidiosis, by contrast, is not zoonotic, and it can also be treated. It tends to be more problematic in organic dairies, mainly because they cannot use the drugs that can be put in feed or water to treat or help prevent this disease. “We can’t use medicated feeds or Corid that can be added to the drinking water. In this situation, it’s a management issue to make sure everything is as clean and dry as possible in the environment of those calves,” says Elder.

“There are two kinds of coccidia protozoa in cattle,” says Erickson. One is Eimeria bovis and the other is Eimeria zuernii. These are species specific, which means cattle can only get it from cattle. People can’t get sick from it. This disease can be dealt with by feeding drugs that disrupt the cellular genetic makeup of those organisms or kills the organisms, like an ionophore,” he says.

Coccidiosis won’t show itself until the calf is at least 21 days old, because this disease has a long incubation period. Even if the calf consumes feces the day it is born, it takes a while for the oocysts to grow and damage the intestinal lining when they replicate. Those new oocysts are shed in the feces about 21 days after exposure. By that time the damaged gut can’t absorb fluid and nutrients very well and the calf has diarrhea.

“There are other causes of scours like salmonella or giardia; we are concerned about contamination of feed or water by animals that may carry these diseases, like birds or rodents,” says Elder. “Rats can be a reservoir for giardia, and lepto—which affects cattle in several other ways including reproductive health, kidney and liver disease. Much of the prevention for any disease goes back to colostrum and the temporary protection it gives newborn calves.”

With any type of scours, dehydration can be a serious consequence; supportive care like fluid administration is important. Monitoring hydration status is crucial, since dehydration is what kills young calves with severe scours. Dehydration and electrolyte imbalance can be deadly. Once a calf goes into shock it can be harder to save.

SEPTICEMIA

Many types of infections can also lead to septic issues. Infections that get into the bloodstream can come from the digestive tract, the umbilicus (navel ill) or the respiratory tract. “Infection can come through the umbilicus if the navel/umbilical cord is not dipped properly. It can spread through the body and settle in joints or various organs. Calves can die from septic infection. Once they go septic it can be difficult to save them,” says Elder.

Dairies should make sure to dip navels of newborn calves with iodine. “If it’s hot, humid weather, like we get here, you probably need to dip them more than once,” says Erickson. “Iodine is antibacterial but is also an astringent and helps dry the navel cord. I talked to dairy farmers in Brazil several years ago and asked them how many times they dipped navels, and it was 6 times! This is a big part of prevention for navel ill, to make sure a moist umbilicus doesn’t serve as a wick for bacteria,” says Erickson.

The definition of septicemia (bacteremia) is presence of bacteria in the blood (blood poisoning), whereas sepsis is a life-threatening, whole-system immune response to an infection, which is often fatal. Even if you manage to diligently treat the calf and it survives and recovers, there may be permanent damage. You have to be exceedingly aggressive in treating a septic calf or it may end up with meningitis, multiple organ failure or long-term health complications, chronic joint damage, and permanently reduced growth performance.

Common long-term complications include septic arthritis. Bacteria circulating during sepsis frequently localize in joint cavities or growth plates, causing chronic lameness, swollen joints, and permanent joint stiffness. Meningitis and neurological deficits occur if the infection spreads to the central nervous system. If a calf survives the central nervous system infection it may show lingering coordination issues, dullness, or behavioral abnormalities.

Chronic lung damage can result if there is secondary or primary respiratory involvement, often leading to permanent lung scarring or chronic pneumonia, limiting future lung capacity and growth potential. Stunted growth and unthriftiness is common in calves that survive acute sepsis. They lag behind herdmates in weight gain and feed efficiency due to prolonged metabolic stress.

Prevention involves good colostrum management and early intervention if a calf does get sick. Septicemia typically hits dairy calves under 2 weeks of age and can often be traced back to failure of passive transfer of colostrum antibodies.

“First signs of septicemia in calves include dullness, fever, weakness, reluctance to stand, and poor suckle reflex. This can progress rapidly to very low body temperature, low blood pressure, rapid and weak heart rate and deep red gums, sometimes with small bruises called petechiae. This is the critical point where calves die,” says Elder.

RESPIRATORY ISSUES

“We tend to see respiratory problems in older heifers rather than newborns. It’s more common in four-month-old calves, for instance, than young ones, but we still see respiratory issues in baby calves. Poor environment and stress can become factors at any age,” says Elder.

Severe weather—exposure to too much cold or heat–can lead to pneumonia. “In some situations, this includes abrupt change in weather, temperature and/or humidity. If a day goes from really cold at night/early morning to very hot and humid afternoon, this can be a huge stress,” Elder says. Any time there is a 50-degree temperature difference or more in a 24-hour period, this can be a risk.

“This is when we usually hear coughing in the calf barns. To prevent this, we must make sure those barns have proper ventilation,” he says. Calves need protection from wind and cold, and from heat and humidity, and buildings need good ventilation. Other complicating factors are stocking density and the ability to isolate sick calves from the group as early as possible.

Prevention of respiratory disease also involves vaccination, to build immunity to common respiratory pathogens after temporary (passive) immunity from colostrum has waned. “Everything works together as a system. You need the vaccines to assist with prevention, along with proper hygiene and husbandry to cut down on exposure to pathogens,” Elder says.

Proper nutrition is crucial; it goes back to colostrum in the beginning, and adequate nutrition afterward, to build a strong immune system. “Everything works together. A chain is only as strong as its weakest link.” You can’t leave a leg off the stool or it will tip over! We have to think about all these things, particularly for disease prevention.

“Diseases like IBR, BVD, BRSV, PI-3 have good vaccines; calves should be vaccinated at 4 to 6 months of age,” says Erickson. “All calves should be also vaccinated for clostridial diseases like blackleg, malignant edema, etc. These are nasty, acute and deadly diseases. Affected cattle die very suddenly,” says Erickson. This vaccine is cheap and effective and should always be included. Every dairy should work with their veterinarian to be able to pinpoint the kind of vaccines needed on that particular dairy.

TAKE-HOME MESSAGE

The diseases we see in calves, such as scours, respiratory issues, etc. all go back to basic management for prevention. “We must ensure proper husbandry. Failure of passive transfer leads to a lot of these problems. If we have a dirty environment, this is a huge factor in disease. A calf could have good-quality colostrum and all the vaccines and still get sick if living in filth; no colostrum or vaccine can prevent problems in that situation,” says Elder. We need everything working together for optimum health.

This means clean environment and no overcrowding and accumulation of pathogens and irritants. “We want their living space to stay clean,” says Lynch. “They go from newborns living by themselves to group housing. Every time we introduce them into larger groups, there is additional exposure and social stresses they must sort out.”

If we do get disease, the crucial question is how to contain it. “This is a big challenge when dealing with pens or barns full of calves. After a calf gets a respiratory disease it often spreads to others. It’s like kids going to school in the fall; they are going to be exposed, and come home with something,” he says.

Good husbandry can also prevent later issues and ensure better performance as an adult. Cows that were sick as calves, even though they fully recovered, may never reach peak potential in the milking herd. “Even if there’s only a couple of weeks where average daily gains are reduced, this will have a longer-term effect on those calves. You want them to get better and back to eating, and normal average daily gain as soon as possible. If illness and lower feed intake lingers for weeks, it always has a negative effect,” says Elder. You may save the calf but she’ll never make a good cow.

“We have to be careful to make sure calves never get sick in the first place, and keep the environment and biosecurity the best it can be.” This can also help keep Johne’s disease from creeping into your herd. Cattle can come into contact with Johne’s at any age, but if they are infected as calves they will show disease signs (weight loss, diarrhea) at 3 to 5 years of age instead of older.

“We always have to think about short term and long term effects regarding proper colostrum, proper vaccination, proper husbandry, management practices, and biosecurity. There is plenty of research showing that healthier calves become healthier cows that perform better,” Elder says. We have the knowledge about how to do our best, but we have to make sure we can implement it.

This is the challenge. “On a busy farm it may be more difficult; when your days are already full and you don’t have enough labor, it can be hard to get everything done, but these things are very important and should not slip off your radar.”

SIDEBAR: DETECTING WHETHER A CALF IS SICK

Sometimes diarrhea is not due to infection. “Depending on amount of milk or milk replacer fed, calves can get nutritional diarrhea, which is not an infection. Just because a calf has a loose stool doesn’t always mean she’s sick. We used to say that if a calf had diarrhea it was sick, but not necessarily anymore,” says Erickson.

“For instance, if we feed 10 liters through an auto-feeder of some kind, those calves will have loose stools, but if they are running around, perky, erect ears, acting normally, they are not sick. You need to look closely at those calves, however, and be able to score them. The University of Wisconsin has a good score sheet that should be on everybody’s farm. You look at the calf and check the score sheet. Does it have a runny nose? There are different levels and give a score. Does it have droopy ears? If the ears look a little droopy you may want to take temperature. If there’s a head tilt or one ear down, this can be a sign of mycoplasma infection. The calf’s head and ears can tell you a lot. You check for runny eyes, runny nose, etc.”

The scoring chart can be found on the UW website. It has a place to list the calf’s ID, age, and a score for various categories to check—nose, eye, ear, cough, temperature, respiration, and a score for fecal material, navel and joints. Below the score sheet are photos of the various scores for nasal discharges, eye discharges, appearance of the ears, etc. and a key on when to treat or to discuss treatment options with your veterinarian.

SIDEBAR: IMPORTANCE OF CLEAN WATER

Make sure calves always have clean water to drink. “I don’t like to see milk in buckets and then people filling those buckets with water without cleaning the bucket,” says Erickson. There’s still residue from the milk, slobber from the calf, etc. This creates a perfect media for bacteria to grow, and can make calves sick. If you are not cleaning pails, you are asking for trouble. There is a protocol on how to correctly clean pails, with a series of acid wash, rinse, etc.

Several years ago, Erickson was at a dairy meeting where a guy from New York spent 45 minutes teaching the dairy farmers how to clean their calf pails. “I thought this was crazy, but later realized he was right. Many people don’t pay attention to this, and not cleaning those pails can come back and bite you, with sick calves. Don’t stack wet pails together. You wouldn’t do that with dishes in your house, and calves are much more fragile than you are.”

There is a tool called an ATP meter that some feed companies and Extension people use. “This is a handheld device that measures adenosine triphosphate to check surface cleanliness. The more ATP on the surface of a calf bottle nipple, colostrum feeder, calf bucket, etc. the more bacteria are present. If the ATP is high, you have bacteria,” Erickson says.

Plastic buckets should be periodically replaced. Plastic can get nicked, scraped or develop tiny cracks where pathogens can hide. “No matter how well you clean, there will be bacterial in there. I prefer stainless steel buckets, and that’s what we use on our farm here. This can be really expensive for big dairies, however, and most of them use plastic. In that situation, when you start seeing tiny cuts and slices in those pails, it’s time to replace them; you won’t be able to adequately clean them,” he says.

Disease prevention mainly comes down to cleanliness. “Calves need a dry, clean place to lie down, ample nutrition, and plenty of calf starter and water. There are some farms that don’t give calves water, thinking that the fluid in the milk or milk replacer is adequate. Water is essential, however, for rumen development. If calves don’t get water, they will be stunted. The water needs to be in a clean bucket, however, and not one that recently had milk in it,” says Erickson.

Back to Home