Johne’s Disease: No Longer Just a Dairy Disease!
by Dr. Gregg Hanzlicek, Kansas State Veterinary Diagnostic Laboratory Associate Director
In a 2017 USDA NAHMS survey, cow-calf producers were asked about their knowledge of Johne’s disease. Over 70% reported “never hearing of it” or “recognized the name, but not much else.” Veterinarians have been discussing Johne’s disease with dairy producers for many years. This is not true concerning cow-calf producers.
Johne’s disease (pronounced yo-knees) was first discovered in the US in 1908. It is caused by a bacterium Mycobacterium avium subspecies paratuberculosis, known as MAP. In cattle and small ruminants, this organism causes chronic, non-treatable bowel disease.
Infection typically occurs in calves during the first six months of life. Infection occurs when the calf consumes feces, colostrum, or milk from cows that are shedding this organism. In some cases, a calf can become infected before birth. Older animals can become infected, but this is rare and only occurs in situations when extreme levels of MAP are present in the environment. Although infection occurs at a young age, the median age when clinical signs occur is five years. We have diagnosed clinical Johne’s in animals as young as one and a half years.
There are clinical signs you can look for. Clinical signs include chronic diarrhea and sudden weight loss. Diarrhea and weight loss occur because the MAP organism produces a chronic inflammatory response that thickens the small intestinal wall. The thickening eventually prevents the animal from absorbing dietary nutrients (specifically protein) into the bloodstream.
The presence of high levels of dietary protein in the intestine “pulls” water from the circulation into the bowel — hence diarrhea. Weight loss occurs because the nutrients contained in the diet cannot be absorbed into the animal’s system through the intestinal wall. Infected animals may eventually die of starvation, even when provided with an appropriate diet.
In the USDA study mentioned earlier, 7.9% of US cow-calf operations were found to contain one or more Johne’s positive cows. In a 2005 Texas study of 115 purebred beef herds, 43.8% of the herds were MAP-positive. The prevalence of this disease in Kansas is unknown, but more than 60 counties have at least one positive sample identified by the Kansas State Veterinary Diagnostic Laboratory. Every Kansas county may contain at least one positive herd.
Why should cow-calf producers be concerned about Johne’s? Very little research has investigated the economic impact of Johne’s disease on cow-calf production. Several dairy studies have shown that MAP-infected cows (non-clinical, test-positive cows) produce significantly less milk and leave the herd at a much earlier age compared to test-negative cows. There is little reason to believe this organism would not have a similar effect on beef cows.
Another area of concern includes MAP’s zoonotic potential. A growing number of human medical researchers have published data to support the concept that MAP causes human Crohn’s disease. According to the CDC, over three million Americans suffer from this disease. Like bovine Johne’s disease, human Crohn’s is a chronic bowel disease, and in some cases, MAP has been found in human small intestines. Human exposure to MAP is believed to occur through the consumption of contaminated water, dairy products, or red meat. This organism has been found in milk, red meat, and drinking water in Europe, and in drinking water in the US.
Johne’s disease is a purchased disease. Keys for a herd remaining non-infected include not purchasing infected replacement heifers, cows, or bulls. Purchased replacement heifers and bulls present a particular problem because our current diagnostic tests are not accurate in animals under two to three years of age. This means testing younger animals before purchase is not appropriate.
The best means of prevention include purchasing animals from herds that have tested all, or an appropriate number of adult animals and all tests were negative. A realistic strategy is to ask the source herd’s owners if they have observed Johne’s disease in their herd. If their answer is no, then testing each purchased animal beginning at two years of age and continuing yearly for the next three years will help identify infected animals. Testing should always be completed as close to calving as possible because the key is to prevent exposure to the MAP organism in very young calves.
Preventing the spread of MAP in a herd includes identifying, through either blood or fecal tests, all shedders before calving and either isolating them from the rest of the calving herd or immediately sending them to slaughter. A key to control is to have a yearly Johne’s Risk Assessment completed by a veterinarian. The risk assessment will help identify those areas of management that provide the greatest risk for young calf infection.
Another key control measure is to minimize the amount of adult manure young calves are exposed to. This can be accomplished by calving in large calving pastures (exactly like neonatal diarrhea prevention), moving each bale ring to a clean area when reloading, frequently moving bunks to clean areas, and if feeding on the ground, feeding in a clean area each day. These activities will minimize the accumulation of adult manure and help minimize calf exposure.
Johne’s is a disease that veterinarians, animal scientists, and cow-calf producers might want to start discussing before consumer confidence in the food we produce decreases and the pressure from outside sources to instill more regulations on the beef industry intensifies.
NCBA and PLC Members Testify in Support of Grazing Bills to Prevent Wildfires
Members of the National Cattlemen’s Beef Association (NCBA) and the Public Lands Council (PLC) testified on November 19 before the US House Natural Resources Subcommittee on Federal Lands in support of legislation to expand the use of livestock grazing as a tool to reduce wildfire risk, make grazing permits more responsive to range conditions, and remove regulatory barriers to the maintenance of critical infrastructure. Each of these bills works together to protect beautiful landscapes across the West and support the ranchers who drive the economic success of rural communities.
“I see such a clear need for the Operational Flexibility Grazing Management Act. This bill provides much-needed flexibility to ensure land managers like me can be responsive to what the land needs while also maintaining compliance with our grazing permit,” testified NCBA member and Utah Cattlemen’s Association President Jeff Young. “Resource management shouldn’t be static; it should be responsive and collaborative. This bill represents an updated, modernized way to manage the land, understanding that you need flexibility to make things work from year to year.”
California rancher and Public Lands Council member Sherri Brennan shared her personal experience from the 2013 Rim Fire that burned over 257,000 acres in Tuolumne County, CA, and the need to prevent recurrent resource damage.
“The combination of reduced grazing and timber harvest, and the lack of meaningful fuel breaks has made many parts of the West one long stretch of high fuel loads. Eight million acres have burned so far this year. What’s worse is that every year, the percentage of total acres that experience the worst kind of fire — high-intensity burns — continues to grow,” Brennan testified. “There’s a way to fix this. Targeted grazing with the intention of fuel reduction can remove up to 1,000 pounds of fine fuels per acre. This means that if the area burns, the fire is likely to be shorter — flames under four feet tall — which means it’s safer for first responders. Less fuel, cooler flames, and safer firefighters should be common objectives.”
Together, Young and Brennan discussed NCBA’s and PLC’s support for the Operational Flexibility Grazing Management Program Act (H.R. 9062) introduced by Rep. John Curtis (R-UT), the Ranching Without Red Tape Act (H.R. 6441) introduced by Rep. Gabe Vasquez (D-NM), and legislation to increase livestock grazing to reduce wildfire risk (H.R. 7666) introduced by Rep. Doug LaMalfa (R-CA).
“Livestock grazing is a valuable tool for protecting our scenic Western landscapes from the ever-present threat of catastrophic wildfire, habitat conversion, and damage from a wide variety of sources,” said Executive Director of PLC and NCBA Natural Resources Kaitlynn Glover. “NCBA and PLC are proud to support legislation that supports and expands the use of livestock grazing as a tool to reduce wildfire risk and we are grateful for leaders like Rep. Curtis, Rep. Vasquez, and Rep. LaMalfa for addressing the needs of Western ranchers.”
Bedding Cattle Yards and Managing Bed Packs
Alfredo DiCostanzo, Nebraska Extension Educator
As another winter sets in, cattle producers are reviewing strategies to manage yards during impending cold and wet conditions. Although one could write volumes regarding how cattle cope with cold temperatures, suffice it to say that keeping cattle as dry and comfortable as possible is key. The following scenarios are outlined here with suggestions on how to best manage yards when winter conditions threaten to reduce performance and affect health.
Precipitation with intermittent dry spells
Other than a dry winter, this may be the next easiest scenario to manage; the operator has two choices: 1) proactively bed if they expect that a cold spell will follow or that the ten-day forecast calls for additional precipitation or 2) do nothing.
Generally, manure is permitted to accumulate during dry spells; yet, during precipitation events, dry manure in high-traffic areas will rapidly absorb moisture. This will lead to rapid accumulation of muck on concrete surfaces (feed and water troughs, aprons and cattle alleys) resulting in difficult situations for cattle, horses, humans, and machinery to get around the pen. Therefore, some operators and many cattle feedlot consultants recommend the removal of dry manure shortly before precipitation is expected. This action needs not to be confined to concrete surfaces. The base of yard mounds or other sloping areas of the pen may also be scraped to remove dry manure.
What might one do with manure that is scraped? Although there is a temptation to haul it away and apply it to fields before the precipitation event, some might consider keeping and piling manure into two-to-four-foot mounds (32 square feet per head is ideal) onto loafing areas (concrete or dirt; away from feed and water troughs). These mounds will serve as high and “dry” areas for cattle to get away from rapidly forming muck and away from traffic patterns in the pen. Once prepared, these manure mounds can also serve as the base where dry bedding is applied.
Precipitation followed by extended cold or additional precipitation periods
This scenario is expected to occur at the start of winter. In the High Plains, deep winter freeze occurs after one or several heavy precipitation events followed by extreme cold temperatures. Thawing from cold temperatures is generally not expected until January, briefly followed by continued cold temperatures, high humidity and precipitation events in February and March.
These are the conditions that set up cattle (and cattle feeders) for performance below expectations and worse than break-even closeouts. When facilities managers consider using bedding on dirt or concrete, they generally refer to these conditions as the trigger for bedding cattle. This is when investing in bedding and managing bed packs makes sense.
How much bedding might be needed to establish the base of a pack?
The initial need to bed a given area surprises most operators. This is because a base must rise at least one foot above the existing surface (bare concrete or manure mound). This requires a minimum of 12 to 14 pounds per head for the initial application; double this estimate if pen conditions are already deteriorating because of rain or snow. This is equivalent to two large round corn stalk bales for a 250-head pen (or four large round bales if it began to rain or snow).
Should the bedding be processed?
For most applications where high traffic will occur (pens stocked heavier, concrete-surfaced pens, cattle nearing finishing weights, and, most importantly, unsurfaced pens), the answer is no. This is because processed bedding will incorporate itself (disappear) into the existing surface by hoof action.
Two key elements of building bed packs, even outdoors, are 1) to continue to keep the areas around the pack free of mud accumulation (it prevents cattle from tracking it onto the pack), and 2) to continue to add bedding to keep it dry.
Scraping around bed packs prevents manure from freezing onto large balls that prevent cattle access to the pack or to water and feed troughs. Adding bedding after scraping can be done with a bale processor or grinder if the base pack is built sufficiently or in pens where there is ample space or lightweight cattle. As a reference (for bedding inventory), prorated over a long period, one might expect to use four pounds of bedding daily per head.
How often are operators expected to scrape and/or bed?
During most winters when cold spells set in, scraping should occur at least once weekly. Bedding should take place immediately after scraping. If scraping stops during subzero temperatures, it cannot be resumed until at least four to seven days of temperatures above freezing. This can create difficult conditions for cattle to get around. When scraping frozen chunks of manure, these can be added to the bed pack before adding dry bedding.
What to do if heavy snowfall is expected? Generally, scraping aprons and high-traffic areas is recommended in anticipation of heavy snowfall (more than three inches) and immediately after it. Snow should be removed from pens as soon as possible after scraping (permitting freshly fallen snow or snow mounds to accumulate in the pen will contribute to ice formation, creating slippery surfaces and exacerbating muddy conditions when snow melts). Bedding before the snow event is recommended. Bedding after scraping immediately after the snow event is highly recommended.
Clearing snow from the perimeter of water troughs should occur as soon after a snowfall as possible. Because of curbs and narrow pads surrounding water troughs, hand labor may be required for this effort. Managing cattle in the yards for cattle comfort, like choosing how much to feed daily, is more of an art than science. .
Ten questions designed to test your beef industry knowledge:
1. What is the term that describes a condition whereby the two toes on a bovine’s foot are fused together?
2. In what country did the Waygu breed originate?
3. A surgically altered male used in heat detection is known by what name?
4. Which vessels carry blood back to the heart?
5. What is the normal body temperature of a bovine?
6. Feeds that are high in total digestible nutrients and low in fiber are known collectively by what term?
7. How many chromosomes does a bovine animal have?
8. If a homozygous polled bull is bred to a homozygous polled cow, what percentage of their offspring would be polled?
9. What is the purpose of hot-iron branding?
10. What government agency is responsible for overseeing the beef checkoff? .
