Vitamin Status Is Behind Calf Wrecks
When a potload of newly arrived calves spends more time in the sick pen than in the feedlot, bovine respiratory disease (BRD) may be the immediate cause. But poor antioxidant vitamin status could be the true culprit.
That's according to Norbert Chirase, a Texas A & M University researcher specializing in feedlot cattle health and nutrition.
“Many feedlot managers don't realize that the levels of the antioxidant vitamins A, C and E just plummet when calves are shipped,” says Chirase. “The lower these levels are, the more calves that are pulled. Cattle with low antioxidant levels are more likely to get sick and to die.”
Although scientists don't fully understand the role of antioxidant vitamins in cattle, they're known to be critical for a healthy immune system. A healthy immune system enables livestock to better cope with stress, including stress related to transportation, diet changes, commingling, dust, hot or cold weather and disease.
In several studies, Chirase and his research group have shown a direct correlation between low antioxidant vitamin status and illness, which translates into poor calf performance.
In one study, for example, 120 feeder steer calves were purchased in Tennessee and shipped to Bushland, TX, to study the effects of transportation and feedlot acclimatization stress. To simulate feedlot stress, one calf group was subjected to simulated dust storms inside a tent.
Calves were weighed and blood samples were taken three days before shipping, upon arrival at the study site and every seven days for 28 days.
Transportation stress reduced serum vitamin E from 7.10 micrograms/milliliter (ug/ml) to 1.95 ug/ml. That's under the critical 2 ug/ml level indicating inadequate antioxidant levels, says Chirase. Calves in the dust stress environment continued to have lower serum vitamin E concentrations (1.88 ug/ml vs. 2.11 ug/ml) throughout the trial.
Average daily gain (ADG) showed a similar pattern to antioxidant levels. On Day 28, ADG of calves subjected to dust was lower than controls (1.95 lbs./day vs. 3.2 lbs./day). All calves were fed a receiving diet with vitamin A at 20,000 IU/kg of dry matter and vitamin E at 300 IU/kg of dry matter.
Data showed that as serum vitamin A and vitamin E fell, calf rectal temperatures increased. BRD incidence increased as well, hinting at the link between low antioxidant status, a suppressed immune system and illness, says Chirase. As BRD incidence increased, serum vitamin A and vitamin E concentrations decreased, as did ADG.
In another study on the impact of stress on vitamin C, calves purchased in Arkansas were backgrounded on receiving diets for 28 days and shipped to Bushland, TX. Shipping stress decreased average blood vitamin C concentrations from 2.67 micro Moles/liter (uM/L) to 0.16 micro Moles/liter, with some calves below detectable levels.
This result was surprising because beef cattle synthesize their own vitamin C, so higher concentrations were expected. “During stress, vitamin C may be used faster than it can be synthesized, or the machinery for making it could be affected by stress,” he says.
Stress creates antioxidant vitamin demands that are higher than are commonly being fed, says Chirase. “There is definitely a decrease in feed intake, too, so the nutrient density should be increased for stressed and sick calves,” he says.
“I would definitely think that we need to be feeding more vitamin E,” Chirase adds. “Vitamin C, which has been protected from rumen breakdown, as well as the trace mineral selenium also would be good candidates. All of these are related. Selenium helps vitamin E and vitamin A in tissue protection. Vitamin C activates vitamin E.”
Chirase suggests livestock producers follow recommendations by consulting nutritionists and vitamin manufacturers on vitamin levels for stressed calves. Because free vitamin C is rapidly destroyed in the rumen, it can't be effectively supplemented to cattle if it isn't in a protected form, he cautions.
Chirase plans to conduct further research to fine-tune vitamin supplementation strategies to counteract transportation and feedlot stress.
Purdue University scientists are using breakthrough molecular research and other new technologies to slash diagnosis time in the battle against Johne's disease. Johne's is a little known, usually fatal infection that costs the U.S. cattle industry $1 billion/year.
USDA estimates that 22% of the nation's dairy herds are infected with the intestinal illness. To make matters worse, the agency says at least 45% of U.S. dairy producers don't know about the disease.
“It used to take us 12 to 16 weeks to get a final diagnosis. Now we can detect the organism as early as two weeks,” says Ching Ching Wu, a microbiologist with Purdue and the Indiana Animal Disease Diagnostic Laboratory.
Testing animals for Johne's is voluntary, but some states prohibit transport of infected animals and/or require they be branded if Johne's infected. Information about existing infection helps producers separate herds so infected animals won't infect the rest of the herd. The goal is to create Johne's-free herds, says Wu.
“Being able to test more samples allows us to learn the extent of the illness's spread and more about its workings,” she adds.
Wu and her group's findings will help advance Johne's control in dairy and beef herds alike. Johne's is spread to animals from infected feed, water and colostrums. Females with high infection can spread it in utero to fetuses.
Most animals are infected at less than six months of age but symptoms don't appear for two to five years.
Brand Name Joint Venture
Excel Corp. and Hormel Foods have signed a letter of intent to form a joint venture to market nationally branded fresh, case-ready beef and pork under the Hormel Always Tender brand name. The product will be sold in supermarkets and club stores.
The joint venture, Precept Foods L.L.C., will be based in Hormel's Austin, MN, headquarters. Excel will supply the fresh beef and pork. Each company will independently maintain existing fresh case-ready programs and other meat programs, such as Excel's branded premium meat products.
Updated Feeding Pubs
Kansas State University (KSU) updated their agricultural economics publications on steer and heifer feeding. The two publications are available on the Internet as portable document format (PDF) files:
The steer publication is available using the following hot link: www.agecon.ksu.edu/livestock/Extension%20Bulletins/MF2547.pdf .
The heifer publication is available using the following hot link: www.agecon.ksu.edu/livestock/Extension%20Bulletins/MF2546.pdf .
Several other KSU publications on cattle economics are also available online at www.agecon.ksu.edu/livestock/Extension%20Bulletins/Extension%20Bulletins.html .
New Food Testing Tech
Marshfield Clinic's Food Safety Services has developed a new polymerase chain reaction (PCR)-based testing technology for the food industry. Marshfield Laboratories, a division of Marshfield Clinic in Marshfield, WI, has expanded its food safety services laboratory to provide a full range of state-of-the-art, food testing services.
Although PCR testing technology has been available for the last two decades, rapid real-time quantitative PCR is recognized as the latest technology innovation.
Marshfield has patents pending on unique DNA sequences for enterohemorrhagic E. coli (EHEC), pathogenic Salmonella species, and Listeria monocytogenes.
Marshfield's food safety program has been working in conjunction with Rosen Meat Group in implementing testing technology into the meat industry. Through its partnership arrangement with Roche Diagnostic Applied Science Group, assays for EHEC will be available within the next several weeks. Assays for pathogenic Salmonella and L. monocytogenes will follow shortly.
For more information, contact Jay L. E. Ellingson, 715/389-5958.
One of the more dramatic year-to-year changes in international trade is in U.S. imports of feeder cattle from Mexico. In the first two quarters of 2002, such imports declined 43% from a year earlier.
Most notably, during June, U.S. cattle imports from Mexico totaled 7,405 head, a decline of 84% compared to 2001. Typically, U.S. Mexican feeder imports are the lowest in summer months, but imports in June 2002 were the lowest since 1989.
During the first six months of 2002, U.S. cattle imports from Canada were above a year ago. Much of that increase occurred in the first quarter when imports were up 35%. In June, U.S. cattle imports from Canada declined modestly compared to 2001.
The first half of the year saw combined U.S. imports of cattle from Canada and Mexico below a year previous. From January to June, U.S. cattle imports fell from 2001 by 130,000 head (1.5%).
— Livestock Marketing Information Center (LMIC).
The latest copy of “In the Cattle Markets” is available on the LMIC Web site at: www.lmic.info/memberspublic/cattlemarkets.pdf  (PDF version) or www.lmic.info/memberspublic/membersreports.html  (HTML version).
Compiled by Clint Peck, senior editor. Contributions are welcome; call 406/896-9068, fax 406/896-9069 or e-mail [email protected] .