Dairy calf gut health

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A newborn dairy calf has the world at its feet, but so often it all seems to go awry and what results is a sick or dead calf that never reached its potential. According to the USDA’s National Animal Health Monitoring System’s Dairy 2007 study, unweaned heifer deaths during 2006 accounted for the highest percentage of deaths among the animal classes at 7.8% (as a percentage of heifers born during 2006 and alive at 48 hours). Scours, diarrhea, or other digestive problems accounted for the highest percentage of unweaned heifer deaths (56.5%), followed by respiratory problems (22.5%).

Sometimes the calving environment is an overwhelming factor in calf morbidity. The NAHMS study reports that the majority of operations (70%) used a multiple-animal calving area/pen, and 34.2% of the operations indicated they allowed sick cows in calving areas. It’s no wonder on some operations that newborn dairy calves have the deck stacked against them.

Colostrum is still a problem

We’ve known for years how to get dairy calves off to a good start—feed them an adequate volume of good quality colostrum shortly after birth. “The NAHMS survey would indicate out of those three factors of timing, quality and quantity of colostrum feeding, perhaps quantity is the most important item that needs improvement,” says Lon Whitlow, MS, PhD, North Carolina State University. “A lot of dairy producers are giving only about two quarts of milk per calf per day. They’re doing a pretty good job of getting to the calf early, but they’re not giving them a great enough quantity of milk. They need a gallon a day and more in cold weather.” To back that up, the Dairy 2007 study indicated that 45.8% percent of operations hand-fed more than two quarts but less than four quarts of colostrum during the calves’ first 24 hours of life.

In 2007, 13% percent of operations that hand-fed colostrum either estimated the immunoglobulin levels of colostrum or evaluated its quality before feeding. The most common methods used for evaluating colostrum quality were a colostrometer and visual appearance.

In addition to the passive transfer issues, there’s a lot of data that’s developing on the roles colostrum plays and it being the gatekeeper for growth, says Jim Drackley, PhD, University of Illinois. “The initial development of the intestinal tract in the first couple days of life is very much dependent on colostrum intake. We know that the basics include getting enough colostrum into the calf as quickly as possible, and that the colostrum should be of good quality in terms of its antibody concentration. Calves that have failure of passive transfer don’t grow with the same efficiency as calves that have had adequate colostrum. Even at the same feed intake, you might get half the growth. Feed efficiency is very much decreased in those calves. It has to start with adequate colostrum status.”

Drackley says most recently, we’ve learned the role of colostrum and sanitation. “There are horrendous bacterial counts in some of the colostrum between the time it’s collected from the cow and actually consumed by the calf.”

Simon Timmermans, DVM, MS, Sibley, Iowa, agrees. “Even guys who religiously put in a gallon of colostrum still have problems. With the dairies we work with, and especially with the Holstein bull calf, we’ve started a HACCP protocol where we collect a random colostrum sample weekly before it goes into the calf, where it has contact with every piece of equipment along the chain — whether there’s a stainless steel bucket that gets milked into, or if it goes through a pasteurizer, we can detect if there is a hygiene problem based on the bacterial count. I think that’s the key reason why we see such better performance out of the beef industry. It’s the human element, and it goes to hygiene.”

Timmermans explains that colostrum is a great culture media for iron-loving bacteria like Salmonella. “The producer may do everything perfectly, collecting that one gallon of colostrum, but then they let it sit out in a bucket for three hours before they get it fed to the calf, or they set it in the refrigerator in a five-gallon bucket,” he says. “It could take 20 hours to chill and slow down the exponential growth of bacteria. These calves are born monogastric and also sterile. The last thing we want is for the first bacteria introduced to be the bad ones without any sort of competitive exclusion existing at all. If you get Salmonella and E. coli coming in at a high load, you have a problem.”

Bacteria can get into colostrum in a variety of ways. The NAHMS study indicated less than 1% of operations that hand-fed colostrum pasteurized the colostrum before feeding it to calves, and Timmermans says, “Pasteurizers are supposed to sterilize milk, but they can sometimes be the biggest contributors to contamination if not properly used and cleaned. And it’s amazing what evil spirits we can grow out of esophageal tube feeders. I grew up on a dairy, too. We’d run in a little chlorine water, a little hot water and swoosh it around in the tube and we’d call it sterile and clean. But a bacterial culture from inside the tube yields a load of bacteria. We need to focus more on running a calf program like the health services would inspect a restaurant. We’re in the food service business.”

Neonatal gut health

A calf is born as a non-ruminant, so it relies solely on milk. If you look at all the digestive systems in the abomasum and the small intestine, the enzymes are there to digest milk components and they struggle with anything that’s not milk, explains Drackley. “They have very little ability to deal with much starch. Milk is nature’s designed first food. Within a few days of age, we start to get increases in some of the enzyme systems that deal with other non-milk proteins and non-lactose carbohydrates. It’s a transition over the first two or three weeks to have the capacity to deal with non-milk ingredients.”

The whole system is meant to digest milk proteins and milk sugars, adds Sylvia Kehoe, MS, PhD, University of Wisconsin. “Milk replacers may have different sources of protein and different sources of carbohydrates, and that’s why some of them work better than others. The faster we can get calves weaned, the better they do. The mortality rate decreases by more than half when they’ve been weaned and the problems move from the intestinal area to the respiratory area. We want to get them digesting very well on a good-quality milk replacer.”

“A healthy gut is very important to the health of the animal,” says Whitlow. “The gut wall is a barrier between the animal and the environment. The speed and development of the gastro-intestinal system is important in transitioning those calves from the milk-consumption period to feeding grain and hay.”

The milk that is fed has to provide for the maintenance of the body, respiration, digestion and many other functions. At the two-week period when passive transfer is decreasing and the calf’s immune system is increasing, that’s when scouring starts. Now the milk has to provide for all of the maintenance needs plus the immune system, and that takes a lot of energy. “If you’re limit-feeding that calf before it’s getting its energy intake from grain, a pound per day, may not be enough, especially in cold weather,” Kehoe notes. “Then you get poor gain. The gastrointestinal tract is the fastest turning-over organ in the body, which means it needs extra nutrients. It’s trying to fight off the bacteria and it’s trying to absorb nutrients and maintain homeostasis. The more nutrition you provide at that point, the better the calf is going to do and the less the scours is going to affect it, and the better it’s going to recover from the challenge. If you don’t provide that nutrition, the gastrointestinal tract never fully recovers and you have an organ that’s not as efficient as it could be.”

Drackley says during the transition time when the calf is encouraged to eat dry feed, “The real functional characteristic that drives development of the rumen is the fermentation that starts once the animal begins consuming some dry feed. The microorganisms in the rumen can start fermenting and get the volatile fatty acids produced, which cause the growth of the rumen papillae or rumen epithelium so the animal can start using the products of microbial fermentation when the calf is able to eat enough to utilize the dry feed, and we can wean the calf.”

“When calves are young, you feed the gastrointestinal tract,” Kehoe says. “They’ve shown many times that if that young animal gets sick, the gastrointestinal tract never recovers. If we can keep the animal from getting sick, there’s a huge amount of money we can save later on.”

The advantage of early feeding on gut health, while benefiting feed efficiency, may have a greater benefit in reducing morbidity and mortalities and thereby improving farm profitability, adds Whitlow.

Whitlow also emphasizes feed sanitation and hygiene which is extremely important with the young calf. “Sanitation is a part of the feed quality factor that is so important in preventing disease and maintaining performance,” he stresses.

A part of the issue with sanitation is also mycotoxins. “The potential for mycotoxin contamination is probably the primary reason we don’t feed silage to calves,” Whitlow explains. “Calves are much more susceptible to the effects of myco-toxins than are cows. Cows are partially protected due to mycotoxin degradation in the rumen. Mycotoxins can reduce immunity and result in gut irritation and digestive upsets.”

Therefore, Whitlow says, it is important to ensure that clean grains are fed fresh daily to calves, that feed is not allowed to get wet, and that feeders are routinely cleaned. Hay or other forage should not be moldy. “If we don’t follow those hygiene and sanitation practices, we’re going to have problems and it doesn’t matter if these problems are classified as nutritional or health-related  —   we have the same poor results.”

Optimizing young calf gut health impacts the bottomline. “How do you get producers to understand?” Kehoe asks. “To them, calf health is just an expense. They don’t see the future earnings, or if they do, they try to make this part as least expensive as possible. We’ve talked about the 50:50 costs of labor and feed, but if a calf gets sick, it’s not 50:50 anymore. You look at these farms that have problems and they’re spending 75% of their time in the calf area trying to maintain these calves so they just survive. They get them to survive and then they have these animals that are cripples as far as growth and production.”

Byron Housewright, PhD, Nutrition Service Co., Pulaski, Wis., says producers need to look at the long-term success of the heifer calf. Housewright, who is also a consulting nutritionist in Texas, adds, “We need them to prioritize and make these calves as critical as the lactating herd. If we take care of these calves, they mean something to us two years from now when we’re trying to get an extra thousand pounds out of them. It means more than just saving $2.25 for that day. It could mean thousands of dollars from increasing our rolling herd average.”

Drackley agrees. “Today, it takes about $2,000 to raise a heifer, and we get hung up over spending $50 during the first six weeks of life. It makes no sense.”

The two areas that should make money and sustain the dairy are the dry cows and the calves, Housewright adds. “You have to take care of those two groups. Feed the calves, feed the dry cows. That’s where you find out whether that dairy’s going to make it.”

Feed them enough

The capabilities of the young intestinal tract are focused on milk, says Drackley. “We ought to be optimizing that ability of the calf. We ought to be feeding more milk or milk replacer than we have traditionally. Calves will grow much more rapidly and efficiently if we allow them to by providing more milk in the first weeks of life. We still can get them transitioned over to ruminants at an early age and go on from there.”

Drackley would prefer to see milk-based ingredients in the milk replacer. “We have to match the protein and energy supplies in the formulation of the milk replacer. If you want to feed for more rapid body development, you have to provide more protein, and those requirements have all been recently worked out in protein-to-energy relationships. At a pound of powder per day, a milk replacer with 20% protein and 20% fat is adequate, but if you want to go to a pound-and-a-half or two pounds per day of gain, then obviously we have to have more protein. So we have to have appropriate milk replacer formulation selected with the goals of the producer.”

Water availability is a huge limiting factor on too many farms, and winter is a special problem because of freezing. Water is highly coordinated with starter intake, so if you’re not providing water, that’s going to slow development. Those are factors beyond just feeding the calf.

From a biological perspective, Drackley would like to wean calves when they are ready. “Let the calf tell us when it’s ready to be weaned. If we look at more-traditional guidelines, the starter intake of a pound-and-a-half is probably pretty accurate. Looking at higher growth rates on milk, then you need at least two pounds a day and the higher it is, the less of a growth slump. But with all that said, we’ve been weaning calves at six weeks of age off of higher milk intakes with no big problems. If you look at the NAHMS survey, the most common weaning age is still eight weeks. After all of our emphasis on early weaning, farmers don’t do it.”

Previous research with calves has utilized the immediate effects of nutrition and management on growth and health as the primary evaluation criteria, says Whitlow. “While these responses are important, researchers are demonstrating that early calf nutrition is even more important in influencing the future milk production and health potential of these animals when they enter the milking herd.”  

This information was based off of a 2008 young calf nutrition roundtable sponsored by Alltech.

Calves can go south fast

It doesn’t take much for the pre-weaned calf to get sick and even die. Calves are born with ~3% body fat, all around the kidney and the heart, says Simon Timmermans, DVM, MS. “Now take those calves in February in Wisconsin and Iowa, followed with E. coli exposure. If it’s just a K99 and we maintain hydration, maybe they’ll get over it. But with a Salmonella, now we have a systemic situation, followed by an immune response, and they’re barely hanging on. Protein and energetic nutrition status will determine their success. They must have the energy to mount an immune response. That’s why we see so many sick calves right around March. The ground is sloppy, maintenance energy requirements are up and there’s not enough energy to fight off the typical diseases and they get sick.”

The people who are going to know if a calf is sick or not sick are the ones who feed it, says Sylvia Kehoe, MS, PhD. “A sick calf is not going to suck down that bottle right. Also, if they don’t get up, we have a very poor chance of getting them back. It can be a quick downward spiral. Some calves look fine in the morning and by afternoon will be dead. Young calves can lose up to 5%–10% of their body weight in water within one day of scouring. Mammals die at 14% of bodyweight water loss, which means that by the time we even start to see symptoms of dehydration, the calf is halfway to dead.”

Hydration status of young calves should be monitored carefully. “You can spot a severely dehydrated calf just by looking at the eyes and seeing if they are sunken in,” says Timmermans. You can tent the skin and see how fast it will snap back. If it doesn’t snap back, that’s usually a sign of dehydration. You can also look at the nose. Is there purulent discharge or a snotty nose? “That would probably indicate some sort of respiratory distress,” Timmermans adds.

Also, take a look at the ears. Is one ear down or are both ears down? “Sometimes if calves get a systemic E. coli or even a Mycoplasma infection, you may see it in the base of the ear, causing the ear to droop,” Timmermans says. “ Attitude is also a good indicator. A depressed attitude will be a fairly accurate indication of sickness.”

A dozen tips for healthy calves

Participants at an Alltech young calf nutrition roundtable discussed some of their top tips for healthy young calves.

  • Colostrum Feed four quarts of good quality colostrum shortly after birth.
  • Use the NRC model for calves “Anyone who does any amount of calf work should use this,” says Simon Timmermans, DVM, MS, Sibley, Iowa. “You can feed all the protein in the world, but if you don’t have enough energy there to drive protein synthesis, then you have an inefficient diet. It also tells you how much to feed in given weather conditions which is a bigger deal in some parts of the country like the upper Midwest.”
  • Thick and fresh bedding “Calves have to be bedded right and it’s got to be thick enough that they’re not exposed to all the bacteria underneath,” says Byron Housewright, PhD, Texas A&M University. “Calves hit the ground in that freshening area and they land in bacteria soup. The whole area where these brand-new calves are is tainted.”
  • Fine tune with feed additives “I always approach feed additives as being at the top of the nutrition pyramid, where you have to have the basics and the foundation fixed first, and you continue to fine-tune as you go up,” says Jim Drackley, PhD, University of Illinois. “I think once you address some of these serious issues about gross under-feeding, there is a variety of products, some of which can add that fine tuning.”
  • Watch weather stress “As we talk about cold stress, we also have to remember heat stress,” offers Lon Whitlow, PhD, North Carolina State University. “We see good evidence that calves are stressed in the summertime. They need shade.” In the winter, use calf blankets where needed.
  • Use a colostrometer to evaluate quality Sylvia Kehoe, PhD, University of Wisconsin, says, “We talk about feeding good quality colostrum, but how do producers decide what’s good quality? They look at it. It’s yellow and it’s thicker than milk so it must be good.” To prove her point that just eyeballing colostrum can’t decipher quality, she has her students visually evaluate two containers of colostrum and asks them which is better. One container is heated and the other kept cool. “The students thought that the cooler one was better quality since it was thicker, however, many of them could not make a decision based on what they could see,” she says. “Yet, we have producers who save poor-quality colostrum based on visual assessment.”
  • Use a meat thermometer Timmermans says using a meat thermometer you can determine if the refrigerator where you store your colostrum is working properly and if your hot water heater is working properly. “You can determine the temperature of the milk being delivered to calves on Jan. 15 at 8:00 a.m. and at negative 10° outside,” he says. “Better yet, you can measure the temperature of the soapy water where you’re cleaning your utensils, because that concept has to be the same as it is for cleaning pipelines in the milking parlor.”
  • Feed calves more milk “We need to feed more milk to these young calves,” Whitlow states. “Along with feeding more milk, we need to emphasize that they get the energy requirement they need. There may be some advantages to feeding additional protein, and we need to look not only at vitamins and minerals, but also nutraceuticals. I think there’s a real place for these products in calf nutrition.”
  • Use a scrub brush Particularly, the insides of bottles need to be scrubbed, and you need a brush that can get inside the esophageal tube feeders, Timmermans suggests. “You really can’t properly clean that unless you have a way to get inside that tube.”
  • Clean the calf cart! adds Kehoe.
  • Quicker detection of scours In barn mortality, 60% to 70% is due to scours, Kehoe says. If producers understand the signs of morbidity, they can have some kind of a protocol in place. “They can tell all of the workers, if you see this, this is what you do. You stick to that protocol, and you have some sort of benefit that the worker can get from doing his job correctly with calves, because it’s too easy to pass off the job to the next guy. You want to get that detection program down quickly. Calves go down so fast that you have to jump right on it to prevent all these other symptoms.”
  • Make calves a priority “It goes back to basic animal husbandry,” Housewright explains. “How many times have we told our students that the first thing we want to look for is abnormal behavior? If a horse or a cow is usually the first or second one in to eat, and she’s last today, something’s wrong. The people who are out there looking at those calves every day are the ones who have to notice the abnormalities. I think management needs to give calves a more prominent role on most of these farms.”

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