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Strategies, risk assessment for infectious diseases in calves

Tamara Scully for Progressive Dairyman Published on 24 May 2016

“Calf health is built on colostrum, nutrition, environment and calf health maintenance,” Dr. Sheila M. McGuirk, DVM, University of Wisconsin – Madison School of Veterinary Medicine, said. “Depending on the farm, one may be more important than another.” (Figure 1)

Making a differenceMaintaining calf health begins during delivery. Normal births should be observed, but assistance should only be utilized when necessary, for abnormal positioning or lack of sustained progress. Having clear birthing protocols, and knowing when a birth is outside of normal parameters, is the first step.

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“At the time of delivery, the calf has some immune capabilities, but they are naive and susceptible to infection, especially before they have received and absorbed colostrum,” McGuirk said. “Calving assistance escalates the risk of infection because stress, pain or injury associated with it may decrease colostrum intake and compromise colostrum absorption.”

Calf environment

Calves are susceptible to disease agents from the immediate birthing environment. Whether the birth is assisted or not, poor calving hygiene increases the calf’s exposure to E. coli, salmonella and other infectious organisms with a fecal origin.

Common causative agents for infectious disease transmission at or soon after birth include the micro-organisms on the mother’s flank, udder and teats, as well as the ones found in the birthing environment – most likely in the bedding.

“Environmental buildup of organisms can be a major problem, especially when newborn calves are kept in an adult cow environment long enough for them to begin standing attempts,” she said.

To combat these prevalent concerns, it is best to remove calves from the birthing pen before they attempt to stand. Aim for a removal time of no more than 10 to 15 minutes after calving. During attempts at standing, calves ingest environmental organisms or collect them on their skin.

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Transfer calves into a clean, well-bedded pen where sanitized colostrum feeding can occur before they become infected with birth pen contaminants. Colostrum can be infected with bacteria and ensuring that colostrum is clean, and remains so during feeding, is imperative.

Colostrum and nutrition

Colostrum can be fed with an esophageal feeder, bottle or a combination. The esophageal feeder is not for use if calves have respiratory concerns or abdominal distension. Calves should be able to maintain sternal recumbency, and using the feeder while the calf is in a standing position is best for the calf, McGuirk advised.

The nose should be kept below the ear. There should be one feeder per calf as needed for delivery of electrolytes or colostrum.

“Farms that want calves raised in group housing need to focus on getting the colostrum program perfect before calves in group housing will thrive,” she said.

Calf health requires ongoing proper nutrition. Not only does the calf need to consume enough calories, it needs to have consistent meals to maintain digestive health.

The environmental temperature plays an important role in feeding rates. The thermoneutral zone for calves is between 58ºF and 62ºF. In environments outside this range, intakes need to be adjusted to compensate for changing energy needs.

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“The most common feeding error is feeding too little. Four quarts of milk or milk replacer per day is no longer acceptable at any temperature,” McGuirk said. “Intakes of 2 gallons of milk a day are much more likely to achieve the growth goals and foster the milk production gains that we want to see in our replacement heifers.”

Consistency means ensuring every meal contains the same amount of total solids, protein, fat and additives. When feeding calves, any changes need to be gradual. Sudden changes cause digestive disruption.

Total solids should not change more than 2 percent from day to day and should never increase beyond 18 percent solids. The proper makeup needs to be maintained from mixing through to calf intake. Variability during preparation, spilled buckets or inaccurate automatic feeders are common issues of concern.

Water, too, is essential to the calf diet and should be made available by day three. Water intake is needed to replace daily losses that occur from the urine, feces, skin and mouth.

And water can help buffer issues if inconsistency in daily feeding does occur. Water needs to be available within 20 minutes of feeding and be delivered warm. Water becomes even more important in calves with diarrhea or for those receiving electrolytes.

Milk or milk replacer requires routine monitoring for quality. Total bacterial counts, as well as coliform counts and E. coli counts, should be assessed and kept below acceptable levels. These levels vary depending on what is being fed. Colostrum, waste milk, pasteurized milk and milk replacer have different acceptable levels. Milk from automatic feeders must be measured through the nipple to account for any contaminants there. (Table 1)Regularly assess milk quality

Screening for diseases

Scours can be a concern in calves. Caused most commonly by rotavirus, coronavirus, cryptosporidia or enterotoxigenic E. coli strains, scours normally occurs in calves younger than three weeks.

But serious illnesses in which diarrhea is a symptom can also occur at a young age. Trained employees can catch additional symptoms which indicate scours is not the only concern. (Figure 2)

The common bugs“Scours, another name for diarrhea in calves, may be due to ingestion of infectious organisms or nutritional issues such as inconsistent diets or poor level of nutrition,” McGuirk said.

“Scours is only common in herds where there is heavy exposure to organisms in colostrum or the environment; when calves are very susceptible because of poor immunity, stress, poor nutrition or a compromised environment; or a combination of these factors.”

Having well-trained personnel screening calves for red flags is an important part of reducing infectious disease risks. Early intervention minimizes treatment costs, lessens the duration of illnesses and reduces the risk of complications. Treating a calf as close to disease onset as possible means better health outcomes.

“Don’t think that detection of disease is just good ‘calf sense,’ a poor appetite or a computer printout,” McGuirk said. “It is scheduled time with calves by someone who has the time and training to recognize calf illness.”

Screening should be a routine part of everyday calf care. Calves found to show abnormalities require further evaluation. Calves that stand or lie when the rest of the pen is doing the opposite, calves that are slow to get up for feeding or any calves with bleeding, discharge, coughing, abnormal posture, sunken eyes or diarrhea are exhibiting signs of concern. (Figure 3)

It takes a defined process

“Calf health maintenance includes prevention of problems, early detection and effective treatment protocols,” McGuirk said. “Find your weak link. If there are more than two weak links, calves will not be as productive and healthy as desired.

Start with the weakest area, strengthen it, and move on to the next.”  PD

McGuirk presented at Cornell University Cooperative Extension’s 2015 Calf and Heifer Congress. Some of the information presented, as well as the accompanying charts, is from her “Assessment, Scoring and Disease Management of Dairy Calves” presentation.

Figures and table provided by Dr. Sheila M. McGuirk, DVM, School of Veterinary Medicine, University of Wisconsin-Madison.

Tamara Scully is a freelance writer from Columbia, New Jersey.

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