cows in field

Ask the Vet: Question & Answer Session a Field Days Session Summary

By Tamara Scully, NODPA News contributing writer

The “Ask the Vet” session at NODPA’s annual Field Days is always a highlight. This year, Dayna Locitzer, DVM, of Green Mountain Bovine Clinic in Chesterfield, New Hampshire, and Elizabeth Martens, DVM, of Valleywide Veterinary Services, Bridport, Vermont, fielded attendees’ herd health questions. Below is a transcript of the session recording.

Calf Health

Foremost on everyone’s mind was concern about the prevention and treatment of calf illnesses. And the primary concern was scours. “We could talk all day about scours,” Dayna said. “We have a bunch of points we think are really important to keep in mind with scours.” The most important thing is to provide colostrum, which provides lifelong benefits and protects immediately from the pathogens which cause calf scours. Colostrum is filled with antibodies, and is the only protection calves have from pathogens, as they have no immune system when born.

“The first thing that will prevent scours, and the most effective thing, is to make sure they get colostrum - ten percent of their body weight- within eight hours, ideally, of birth,” Elizabeth said. “Colostrum is full of antibodies to the same exact bacteria and viruses that cause diarrhea. We call it ‘liquid gold.’ There is nothing better than that, and it follows them for their entire life as far as health and production outcomes. There is no replacement for sufficient colostrum.”

A second important factor in the prevention and treatment of scours is understanding when particular pathogens are most likely to cause illness, Dayna said. Different pathogens are the primary scours-causing agents at various stages of calf growth.

Escherichia coli is the cause of scours from birth to 10 days of age. It is associated with manure in the environment. When newborn calves ingest manure, they absorb it - as they do colostrum - very well. And that manure contains E. coli bacteria, which then causes scours. Cleanliness in the birthing pen is of the utmost importance in preventing the pathogen from entering the digestive tract.

Coronaviruses and rotaviruses cause scours from 10 days to two weeks of age. These are prevented via vaccinating the dry cow with Scourguard ® several weeks prior to birth, or by providing antibodies in the form of First Defense ® Tri-Shield™ paste to the newborn calf, both of which also protect from E. coli scours.

Cryptosporidium is yet another pathogen causing calf scours, which appear at the same time as does viral-caused scours. Providing calves with proper nutrition - a minimum of 10 percent of their body weight in milk per feeding - will help to keep this pathogen at bay.

Coccidia is an oocyte, and causes scours which occur after a few weeks of age. These pathogens are spread in manure, and the oocyte can live for quite some time, depending on environmental conditions, without a host.

It’s important to avoid common myths about treating scours, Dayna said. One misconception is that feeding milk to calves with scours is harmful, and the other involves electrolytes.

Calves need to receive the highest plane of nutrition, which comes from adequate milk feeding, so feeding milk remain essential. Feeding smaller amounts of milk at a time could be helpful when treating scours, as the sick calves do have digestive problems.

“They are growing animals, and building all of the important foundations for being good milk cows, and they need that nutrition,” Dayna said.And while electrolytes are important, all electrolytes are not created equal, and many do not have the ingredients a calf with scour needs. A calf with scours is dehydrated, but also has too much acid in the rumen. They feel weak, don’t want to suckle, have low blood sugar from not absorbing food, and tend to be cold. Keeping them warm and dry, as well as fed and hydrated, are all important.

Not drinking or eating exacerbates the original problem of dehydration from the diarrhea. Electrolytes will provide fluid, but also need to neutralize the acid. Some electrolytes don’t even contain products which help with the overabundance of acid.

“There is such thing as bad electrolytes. It’s important to feed them the right kind of electrolytes,” Dayna said. “Not all of the electrolytes are listed on what’s approved for organic, so check with your certifier. If it’s not approved, it can sometimes be approved.”

A traditional type of electrolyte has bicarb - such as inexpensive baking soda. But if fed orally, baking soda will go directly to the abomasum - the calves don’t yet have a functioning rumen - making it less acidic. But in doing so, the calf is less able to protect against stomach bacteria, and the bicarb actually lowers defenses from environmental bacteria.

Propionate and acetate are other forms of base and are often found in commercial electrolytes. These neutralize the acids, but do not also lower the calf’s ability to fight off environmental bacteria in the stomach. Hydrolyte® is one commercial electrolyte recommended.

“Make sure that you are getting a really effective electrolyte that’s not only giving them fluids and sugar, but also something that neutralizes the acid, and makes them feel better,” Elizabeth said.

It’s really important that calves get milk and electrolytes, but without a good suckle reflex, getting these into the calf can be challenging. Tubing a calf requires a suckle reflex. Without it, the gastrointestinal tract isn’t moving, and tubing them will lead to problems, as the fluids will sit in the abomasum and cause bloating and promote growth of pathogenic bacteria, which could led to death. Intravenous fluids are needed if there is no suckle reflex. “If they don’t have a suckle reflex, they need IV fluids,” Dayna said.

“When an animal has scours, or diarrhea, the part of the intestine - the villus - that creates lactase enzymes that digest that sugar, the very tip of it is the first thing that gets inflamed...and that’s the part of it that makes the enzyme. They become slightly, temporarily lactose intolerant while they have scours,” Elizabeth explained.

Adding back lactase in the form of a supplement, just as human’s who are lactose intolerant do - assuming it is allowed in organic production - is one way to help the calf digest milk and prevent the milk from fermenting in the intestine and causing more problems. It’s not a cure for scours, but it helps.

A discussion on whether lactase is allowed in organic production*** - and recognizing that even if so, some commercial products may contain other ingredients that might not be allowed, as well as whether or not feeding raw milk would allow digestion without lactase enzyme needed- ensued.

***Bea Hammond of Vermont Organic Farmers/NOFA-VT has researched Lactaid and heard from the Johnson & Johnson Company with the GMO information that was needed for Lactaid. Lactaid is now an allowed healthcare product for VOF producers. ***

As all milk has the sugar lactose, including raw milk, and the only way the lactose sugar can be broken down is via the enzyme lactase, true lactose intolerance means that raw milk cannot be digested, Dayna said. So raw milk would not be digestible by the calf with scours.

Scours can be very serious. One attendee stated that they had no problems with scours for years, until they suddenly did, and half of their calves died. They could not get it controlled until they had it cultured, and realized that it was being caused by a pathogen - rotavirus - that their calf preventative regimen was not targeting. Once they began using a product that contained antibodies for rotavirus, the scours was eliminated.

Pink Eye

There has been discussion about pink eye on the ODAIRY forum recently, and pink eye was also a hot topic for the Ask the Vet session. Pink eye is often caused by two distinct pathogens, Moraxella bovis and Moraxella bovoculi, and each requires a separate vaccine. Other pink eye pathogens cannot yet be vaccinated against, such as mycoplasmas, which are also primary pathogens. Pink eye infections are often caused by more than one microbe simultaneously.

“Unless you are vaccinating against all the different types of pink eye that you are dealing with, vaccination is not going to really prevent a large outbreak,” Dayna said. “Vaccine failure when it comes to pink eye is quite common.” Using autogenous vaccines - made by culturing the pathogens on your farm and vaccinating against them- and keeping boosters and vaccinations up-to-date, could help. But autogenous vaccines are not always economically practical, and cultures need to be done every few years.

Calves should be vaccinated a few months prior to being introduced to pasture, and boostered several times before being turned out onto grass, as tall grass and flies are often co-factors in pink eye outbreaks. Flies spread the pathogens, while tall grass or other conditions such as ultraviolet light, blowing dust, or sand serve as irritants to the cornea. Damage to the cornea then allows pink eye bacteria to enter. Because there is not blood supply in the cornea, healing is difficult.

“Flies are huge. They not only damage the cornea; they spread the bacteria,” Elizabeth said. “Anything that damages the cornea can allow that bacteria in.”

Saline solutions, or taking blood from the sick cow using a red-topped tube and centrifuging and drawing off the top fluid to introduce into the eye, will promote healing. Sewing the eyelids shut or using eye pads can help protect from ultraviolet light and lessen irritation. Antibiotics don’t do much except decrease the duration of the illness by a day or two.

Ringworm, a fungal pathogen, was also discussed. While primarily a problem in less healthy calves, ringworm causes a skin infection and as such the immune system is not directly involved in combating the disease. It tends to appear around weaning, when calves are under stress. While it normally subsides on its own after about six weeks, there are measures which can shorten the duration and provide healing. Apple cider vinegar, oregano oil, garlic and kelp were all considered options as anti-microbial agents that might decrease ringworm’s duration early in treatment.

“I don’t think it’s the ringworm causing them to not do well; it’s the other way around,” Elizabeth said.

Minerals and vitamin levels should always be adequate. Kelp does provide trace minerals, and is good as a buffer for stressful times. Kelp has iodine, and can be used during weaning to promote healthy calves. Vitamin E and selenium are also recommended. A calf with a strong immune system isn’t as susceptible to illnesses.

Cow Health and Vaccines

Pneumonia in cows was addressed. Prevention is really important with pneumonia, as there aren’t many effective organic treatments. The pathogens - both bacteria and virus - causing pneumonia are already in the mouth of the cow. Increased stress can cause them to migrate into the respiratory tract.

Often acute pneumonia is cultured and shows that bacteria are the causative factor in death. Vaccinating for both bacteria and viruses - and doing so during the targeted times when infection is most likely - is recommended.

“In the face of an outbreak, we don’t want to inject the respiratory vaccine, you want to do the intranasal,” Elizabeth said, as nasal vaccines will begin to provide antibodies within hours. “Nasal vaccines are great. Injectable vaccines weeks before are even better, because they prime the entire system.”

It’s not the sick cow that needs the intranasal: They are already infected. But cows without symptoms can be rapidly provided some protection with nasal vaccines. Nasal vaccines have shorter durations of effectiveness, but work more quickly.

“Making sure her neighbor gets the intranasal vaccine,” is of primary importance, Dayna said. “That immunity that you’re putting directly into the nasal passageway is going to help to prevent her from getting what her stall mate has.”

Some producers spoke of not using vaccines and not having problems with disease for many, many years. Then suddenly, they lost many animals when a disease outbreak occurred.

“You’re going to be fine for ten years. And then something will happen and your vaccine would have paid for all those years,” of not vaccinating, by preventing cow illness and death, Elizabeth said.

Aside from discussing illness, the veterinarians talked about good cow health.

Time budgets were a concern for one producers, who said his cows, when outside in the middle of the day in winter, were all lying down. But they first stand in the barnyard for hours after being let out. He wondered why they did this.

“Does a cow know when she needs to lie down?” he asked.

At least seven hours a day lying down, preferably 12 hours, is needed, Dayna said. If nothing is preventing the cows from lying down, they will. A time budget of three hours of socializing is also part of the cow day. Perhaps his cows are doing their socializing in the barnyard, prior to going out to the field and lying down. Otherwise, it could be due to their not liking the transition from the dark barn and into the bright light.

Both of the veterinarians have been intrigued by “happy lines,” the slightly raised, always present lines seen on both sides of animals with good hair coats, and wanted to share their observations with the NODPA dairy farmers. During vet school, they wondered exactly what they are, but without a biopsy they can’t be definitely sure. Healthy fats might play a role. They’ve observed them on conventional and organic herds.

Seeing happy lines is an indicator of overall good health, they both agree, no matter exactly how they form, or what makes them appear. Cows with happy lines should have good immune systems.

Providing calves with colostrum, adequate milk, clean environments, mineral supplementation, vaccinations and preventative antibodies should go a long way towards creating cows with those happy lines. And that will put a happy face on every organic dairy farmer.