Beef Cattle Browsing – March 2007

Beef Cattle Browsing

Editor: Dr. Stephen Hammack, Professor & Extension Beef Cattle Specialist Emeritus

March 2007

This newsletter is published by Texas AgriLife Extension – Animal Science. Media, feel free to use this information as needed and cite Texas A&M University Beef Cattle Browsing Newsletter, Dr. Steve Hammack.

Not according to the Kansas State University Veterinary Diagnostic Laboratory. Substantial progress has been made in moving injection sites from locations on the body that produce better cuts of beef, especially the hip, to the generally recommended location of the neck. But there are other concerns. The KSU lab reports instances of cellulitis from injections, sometimes leading to death. The main culprits appear to be dirty syringes/needles and storage and injection of partially-used vaccines. Follow good vaccination procedures to have not only a wholesome product but also healthier, better performing cattle. (Kansas State University Veterinary Quarterly Vol. 10, No. 1)

Highly stressed, newly received cattle present significant management challenges. University of Arizona and Texas Tech researchers reviewed almost 150 papers on this subject. The most common problem is the viral complex involved in bovine respiratory disease (BRD). The authors found that viral outbreaks often lead to bacterial infections, the most common being Pasteurella  (Mannheimia) haemolytica. These diseases are often associated with the various stresses of weaning, marketing, transportation, nutrition changes, genetics, and health background. Preconditioning programs which include preweaning castration and viral immunization reduce incidence of BRD. Antibiotic treatment can be effective and new products offer more choices, but drug use in food-producing animals worries some consumers.

New calves often do not eat adequate amounts of feed. To compensate for low feed consumption, high-energy receiving rations are often used, which also generally increase early gain and feed efficiency. But those rations, which are low in roughage, also may increase sickness. Rations either high or low in protein should be avoided. Satisfactory levels of trace minerals appear to be a factor, but results from supplementation are inconclusive. Supplemental Vitamin E in receiving rations appears to reduce sickness, but does not affect performance. In conclusion, the authors stated, “our ability to modify the incidence of BRD through nutritional manipulations seems limited” and  “we recommend that the nutrient content of diets for newly received cattle be formulated to adjust for low feed intake associated with stress”. (J. Animal Sci. 85:823)

When environmental conditions vary, especially nutritional, so can animal performance. Cows on good nutrition are able to consume enough for their maintenance, growth (if they’re not mature), and milk production. If nutrition is lacking, cows will lose weight and/or milk less. Researchers at Colorado State University and Massey University, New Zealand, wanted to know if differences in environment affected estimates of heritability. They analyzed Red Angus Association of America data including over 96,000 records of cow body weight from over 34,000 cows and over 27,000 calf weaning weight records. Change in cow body weight from one year to the next was used to classify the environment as either good or poor. There was no difference between environments in estimates (0.24) of direct heritability of weaning weight (involving genetics for growth passed from dam to calf). For maternal effects (involving genetics of the dam for maternal influence, mostly milk production) heritability was 0.13 in the good environment and 0.14 in the poor environment. The authors concluded there was no need  to consider differences in dam environment in national genetic evaluation programs that calculate EPDs. (J. Animal Sci. 85:610)

A considerable amount of time and effort is expended on improving carcass quality through genetics. Wouldn’t it be nice if there was something that could simply be added to feed to do the same thing? Previous research showed that marbling scores were higher in carcasses from grazed cattle with supplementation of Tasco, a feed additive produced from brown seaweed. Texas Tech University and Auburn University researchers used 100 steers of about 75% Bos taurus – 25 % Bos indicus genetics to evaluate effects of Tasco in a finishing program. Half of the steers were fed Tasco for 14 days starting after 45 days on feed and again for 14 days before slaughter.

Tasco feeding resulted in significantly higher marbling scores and higher percent grading Choice and tended to have more desirable Yield Grade. However, Tasco had no significant effect on machine tenderness or taste panel evaluation of strip loin or inside round steaks, except that initial tenderness (before aging) of inside round steaks was significantly better for Tasco. Tasco steaks generally showed better color and less discoloration during aging and presentation in the retail meat case. The authors concluded that Tasco supplementation “increases carcass quality and prolonged retail shelf life”. (J. Animal Sci. 85:754)

The National Beef Cattle Evaluation Consortium has published a comprehensive guide to selection of beef sires. The 78-page manual covers genetic principles, crossbreeding, choosing breeds, Expected Progeny Difference, visual and phenotypic evaluation, DNA-based tools, and more. It can be accessed at

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