Mycoplasma Management Reminders -- Part II

With the fall run of calves knocking at the door, it pays to keep in mind management associated with a decreased incidence of mycoplasma (non-responsive pneumonia and arthritis).

With the fall run of calves knocking at the door, it pays to keep in mind management associated with a decreased incidence of mycoplasma (non-responsive pneumonia and arthritis). As researchers at Kansas State University (KSU) noted in the mycoplasma survey they conducted among stockers and backgrounders in 2001, "As mycoplasma appears to be an opportunist occurring most frequently during times of stress or when a calf's immune system is weakened, management programs should focus on those procedures that can get calves started out in the right direction."

Recommendations by KSU researchers include:

  • Don't feed poor-quality hay, or hay in a form not easy for incoming cattle to eat. The relationship between poor nutrition and increased susceptibility to disease has long been recognized. Feed intake during the receiving period is typically low which potentiates the stress effects of shipment, processing and illness (Hutcheson and Cole, 1986).

    Calves need a high-quality, palatable diet on arrival. A high percentage of survey respondents were using native-grass hay in receiving diets. Not all native-grass hay is created equal. In Kansas, forage quality deteriorates monthly from peak protein values in May and June until September with crude protein values declining from a peak of around 9% to 4% (Baker and others, 1999).

    The best way to know what you're feeding is to get your hay tested before the cattle start arriving. You can then build a receiving ration to match the needs of stressed cattle using a readily available hay commodity.

    Protein concentrations in the entire receiving diet should be in the 13.5-14% range. Limiting dietary protein can decrease immune function and increase susceptibility to respiratory pathogens. Calves already sick have decreased appetites and need additional protein in their diets to offset lowered intakes.

    If using native hay in receiving diets, feed it in a form that minimizes the amount of time a calf has to work at eating. Unbroken, large, round bales require a lot more effort to eat and may limit the number of calves eating at one time. Breaking hay out into bunk-line feeders and top-dressing the protein and energy portion of the ration, or using a complete ration during the first two weeks, will increase consumption.

  • Provide a trace-mineral program that meets or exceeds recommended allowances for the weight of calf purchased. A nationwide sampling of zinc content in forage samples found only 2.5% to have adequate levels of >40 ppm (Corah and others, 1996). It appears most pasture-management programs require some form of mineral-supplementation program.

    Several trace minerals, including zinc, are critical for proper immune-system function. If the likelihood of receiving cattle from an area where forage zinc is low isn't risky enough, zinc serum levels will also decrease during transportation and stress. In a recent survey of feeder cattle by the authors, serum zinc levels on arrival were found to be deficient in 35% of incoming cattle sampled. In the same operation, 30% and 55% of cattle sampled at first treatment or at re-pull for treatment, respectively, were found deficient. Cattle didn't appear to have serum zinc levels return to normal until more than 60 days in the feeding program, even though ration levels were adequate.

    Pasture mineral supplementation programs will carry over into the feedyard program (Greene and Chirase, 1998). In a Nebraska mineral-supplementation study, cattle receiving supplemental trace minerals (zinc, copper, manganese and cobalt) during the summer-grazing period had significantly fewer sick calves and fewer treatments per episode than unsupplemented cattle (Grotelueschen and others, 2001).

  • Get control of a respiratory disease early. Metaphylaxis is the group treatment of high-risk cattle with antibiotics before clinical signs of illness are present. The survey indicated a significant difference in the frequency of use on affected operations as compared to operations not receiving affected loads. That begs the questions: "Did it cause the problem?" or "Did they use metaphylaxis in an effort to prevent affected loads because they'd had affected loads before?"

    Neither question is answerable. In the final analysis, metaphylaxis didn't appear to play a significant role -- data suggests that within operations using metaphylaxis there didn't appear to be any relationship between affected loads and unaffected loads receiving the procedure.

    Metaphylaxis is a proven management practice to help reduce sickness, chronics and death loss rates in high-risk cattle. Its usefulness has been shown over many research trials and remains a practical management tool for targeted loads of cattle.

  • Minimize additional stresses at processing. If you can't buy steers and clean-headed cattle, delay those procedures for about 30 days post-arrival. Cramming them on top of everything else at arrival just adds to the stress load.
The complete survey is available at