Skip to the content

Kansas State University


Beef Research News
Brought to you by Kansas State University College of Veterinary Medicine - Farm Animal Section
August 2006





New animal drugs for use in animal feeds; Melengestrol, Lasalocid, and Tylosin

Federal Register: July 12, 2006 (Volume 71, Number 133)
Department of Health and Human Services
Food and Drug Administration
SUMMARY: The Food and Drug Administration (FDA) is amending the animal drug regulations to reflect approval of an abbreviated new animal drug application (ANADA) filed by Ivy Laboratories, Div. of Ivy Animal Health, Inc. The ANADA provides for use of single-ingredient Type A medicated articles containing melengestrol, lasalocid, and tylosin to make three-way combination drug Type C medicated feeds for heifers fed in confinement for slaughter.
DATES: This rule is effective July 12, 2006.
FOR FURTHER INFORMATION CONTACT: Daniel A. Benz, Center for Veterinary
Medicine (HFV-104), Food and Drug Administration, 7500 Standish Pl., Rockville, MD 20855, 301-827-0223, e-mail:

Heat Stress in Feedlots
Summer temperatures have been soaring and cattle on feed have felt the effects. Minimizing the negative impacts of heat on cattle is a challenge for many feedlot producers. Heat stress reduces performance by limiting intake and can also lead to death in severe conditions. High ambient temperature, relative humidity, sunlight, and very little wind combine to increase animal heat load. Management strategies for managing thermal stress include providing shades, adequate clean water sources and sprinkling the animals and the environment. Wetting the animals allows them to cool through evaporation of the water. It is important to soak the animals rather than mist them as misting increases the humidity in the environment and can create an insulation layer. It is also important to be sure there is ample room for all animals to drink as needed; supplemental water tanks in the pen may be helpful during prolonged periods of heat. Several articles listed below evaluated the aspects of heat management in the feedyard.

T. L. Mader, M. S. Davis, and T. Brown-Brandl. Environmental factors influencing heat stress in feedlot cattle J Anim Sci 2006 84: 712-719.

T. L. Mader and M. S. Davis. Effect of management strategies on reducing heat stress of feedlot cattle: Feed and water intake J Anim Sci 2004 82: 3077-3087.

F. M. Mitlöhner, M. L. Galyean, and J. J. McGlone. Shade effects on performance, carcass traits, physiology, and behavior of heat-stressed feedlot heifers J Anim Sci 2002 80: 2043-2050.

F. M. Mitlohner, J. L. Morrow, J. W. Dailey, S. C. Wilson, M. L. Galyean, M. F. Miller, and J. J. McGlone. Shade and water misting effects on behavior, physiology, performance, and carcass traits of heat-stressed feedlot cattle J Anim Sci 2001 79: 2327-2335.

Research Evaluates BRD in Feedlot
Recent research reported in the Journal of Animal Science characterized the genetic, environmental, and economic factors related to incidence of bovine respiratory disease (BRD) in feedlot calves. Records from 18,112 calves representing 9 breeds and 3 composites over a 15 year period were evaluated. BRD incidence ranged from 5-44% through the years. The epidemiological pattern indicated that BRD infection increased dramatically after 5 d on feed. BRD infection in the feeding phase was not influenced by previous BRD infection prior to sending to the feedlot. Evaluation of BRD incidence rates between breeds revealed few significant breed differences. Purebred and composite breed types had similar susceptibility to BRD. Heritability for resistance to BRD ranged from 0.04 to 0.08 ± 0.01. When the observed heritability was transformed to an underlying continuous scale, the estimate increased to 0.18. The authors theorized that selection for BRD resistance could occur, yet and phenotypes for BRD resistant animals must be identified. The study also estimated the economic losses associated with lower gains and treatment costs for BRD infection in a 1,000 head feedlot to be $13.90 per animal. This figure did not include labor and handling costs for treating the sick animals.

G. D. Snowder, L. D. Van Vleck, L. V. Cundiff, and G. L. Bennett. Bovine respiratory disease in feedlot cattle: Environmental, genetic, and economic factors J Anim Sci 2006 84: 1999-2008.

KSU-CVM Farm Animal Expands Faculty
Dr. Meredyth Jones joined the Farm Animal section in the Kansas State University College of Veterinary Medicine. Dr. Jones will be board certified in food animal internal medicine and will be working in the field services section. After completing her doctor of veterinary medicine, Dr. Jones entered private practice in a Kentucky mixed animal practice. She later returned to Oklahoma State University where she completed a residency in food animal medicine and surgery. Dr. Jones research interests are small ruminant urolithiasis and nutritional support for critically ill animals.

2005 Beef Quality Audit

RENO, Nev. (July 11, 2006) – Initial results from National Beef Audit 2005, funded in part by checkoff investments in the Beef Quality Assurance Program, are in and offer U.S. cattlemen insight into beef quality successes and future challenges over which they have some or all control.

Identified in the new audit as the top three quality successes since the 2000 audit were: (1) improved microbiological safety; (2) improved cattle genetics and beef of higher quality; and (3) fewer injection-site lesions. The rankings are from interviews with beef end-users, including exporters, purveyors, foodservice and retail channels.

Of note to producers, as more foreign markets reopen to U.S. beef, was the response from beef exporters on the question, “What one quality attribute could U.S. cattlemen change to make it easier for you to export beef products?.” Exporters’ response: “source and age verification,” followed by “more marbling.”

Asked to cite “the gold standard” for high-quality beef in foreign markets, exporters ranked U.S. Prime No. 1, followed by U.S. Choice. As for the perception foreign buyers have about U.S. beef flavor and tenderness, 100 percent of those surveyed rated tenderness as “very good.” Seventy percent rated the flavor of U.S. beef as “excellent,” while 30 percent gave the rating of “very good.”

As for new opportunities in the “natural” market, respondents predicted just over a 14 percent increase in domestic consumer demand for “natural” beef products in the next 10 years, while international demand is expected to grow by just over 10 percent.

“Lack of uniformity/consistency in quality” was ranked by end-users as the No. 1 defect in the U.S. beef industry. That lack was further defined by four things: (presence) of marbling; tenderness; palatability; and inconsistency among and within quality grades.

Other defects identified included cuts being too large for foodservice/restaurant trade; excess fat; abscesses/lesions in cuts, trimmings and variety meats; blood splashed muscle; pathogens and food safety; dark cutting muscle/lack of uniformity in size/shape/weight; blood clots in cuts and trimmings; bruises; and lack of traceability to meet export requirements.

The national audit was conducted by researchers and scientists from Colorado State University (Fort Collins); Texas A&M University (College Station); Oklahoma State University (Stillwater); and West Texas A&M University (Canyon).

The study was conducted between July 2005 and June 2006. The work included interviews with beef and beef product export decision-makers, and with purveyors, restaurants, foodservice operators and supermarket officials.

Specific quality data were collected at 16 U.S. packing plants. The audit collected data for live cattle, carcasses/offal items on the harvest floor and carcasses after chilling and after ribbing at the 12th/13th rib interface.

The beef audit is conducted every five years. It is part of the Beef Quality Assurance Program, which was initiated by producers in 1982 and is the nation’s oldest pre-harvest herd management education program. Programs that certify trained producers in quality pre-harvest practices are active in 47 states. Program materials are funded by the beef checkoff.

BVD Vaccination in Calves
A recent study reported in JAVMA showed that a single dose of an MLV multivalent vaccine containing BVDV administered at 4 to 5 weeks of age can stimulate a strong protective immune response in calves in the face of high concentrations of maternal antibodies against BVDV. The protective response in vaccinates was not associated with an increase in serum antibody concentrations.

23 crossbred dairy calves were assigned to one of three treatment groups:1 ) control – fed colostrum not containing antibodies to BVDV and receiving sham vaccine, 2) colostral antibody-negative and vaccinated - fed colostrum not containing antibodies to BVDV and receiving a commercial BVDV (type 1 and 2) MLV vaccine, or 3) colostral antibody-positive and vaccinated – fed colostrum containing antibodies to BVDV and receiving a commercial BVDV (type 1 and 2) MLV vaccine. The calves were vaccinated at approximately 5 weeks of age. The calves were challenged with virulent type 2 BVDV 3.5 months after vaccination.

Control calves that were fed colostrum that did not contain antibodies against BVDV and received a sham vaccine developed severe disease (4 of 7 calves died or were euthanized). Calves that were vaccinated with the commercial vaccine (whether or not they received BVDV antibody-containing colostrum) developed mild or no clinical signs of disease. In addition, BVDV was isolated from 6 of 7 control calves beginning on day 3 and continuing through day 13 after challenge. Virus was not isolated from any calves in the other treatment groups.

Zimmerman AD, Boots RE, Valli JL, Chase CCL. Evaluation of protection against virulent bovine viral diarrhea virus type 2 in calves that had maternal antibodies and were vaccinated with a modified-live vaccine. JAVMA 228(11):1757-1761, 2006.

BVD Heifer Vaccinations
In another study published in JAVMA, seronegative heifers vaccinated with 1 dose of a MLV BVD vaccine containing both types 1 and 2 had fewer PI calves than heifers vaccinated with either 1 or 2 doses of a MLV vaccine with only type 1 BVD.

160 heifers seronegative to BVDV and that had never been vaccinated against BVDV were used. Heifers were either given one of 4 treatments: 1) a placebo vaccine only (controls), 2) 1 dose of an MLV vaccine containing type 1 BVDV, 3) 2 doses (120 days apart) of an MLV vaccine containing type 1 BVDV, 4) 1 dose of an MLV vaccine containing both types 1 and 2 BVDV. The heifers were bred naturally and then exposed with a type 2 BDV field isolate (heterologous to vaccine strain) between 62 and 104 days of gestation by instillation of the challenge inocula into the nostrils.

At parturition, virus isolation and immunhistochemical analyses of ear-notch specimens were used to determine persistently infected (PI) status. 18 of 19 calves from heifers in the control group were PI, 6 of 18 calves from heifers receiving 1 dose of type 1 BVDV, 7 of 19 claves from heifers receiving 2 doses of type 1 BVDV, and 0 of 18 claves from heifers that received 1 dose of the type 1 and 2 BVDV vaccine were PI.

Ficken MD, Ellsworth MA, Tucker CM, Cortese VS. Effects of modified-live bovine viral diarrhea virus vaccines containing either type 1 or types 1 and 2 BVDV on heifers and their offspring after challenge with noncytopathic type 2 BVDV during gestation. JAVMA 228(10):1559-1564, 2006.

Beef Research News is produced by the Farm Animal section at Kansas State University. To modify your subscription to this service please email Erin Thomas ( )

For more information please contact:
Brad White, DVM, MS
Beef Production Medicine
Q211 Mosier Hall
Manhattan, KS 66506