How Mineral Injections Affect Immune Response and Health in Feedlot Cattle

Jenn Hoskins
10th June, 2024

How Mineral Injections Affect Immune Response and Health in Feedlot Cattle

Image Source: Matthias Zomer (photographer)

Key Findings

  • The study from Iowa State University focused on improving cattle's resistance to bovine respiratory disease (BRD) using injectable trace mineral (ITM) supplementation
  • Cattle given ITM before infection had higher selenium levels, which can boost immune cell function
  • ITM-treated cattle showed reduced severity of disease symptoms and lung lesions compared to untreated cattle
Bovine respiratory disease (BRD) is a significant health concern in the cattle industry, often leading to severe economic losses. The disease is primarily caused by bacterial pathogens such as Mannheimia haemolytica, Pasteurella multocida, and others[2]. These bacteria, normally harmless in the upper respiratory tract, can invade the lungs under stress, causing severe respiratory issues. Recent research from Iowa State University[1] has investigated the potential of injectable trace mineral (ITM) supplementation to enhance disease resistance in cattle, particularly against bacterial infections like M. haemolytica. The study involved 32 Angus-crossbred steers, divided into three groups: a control group receiving sterile saline (CON), a group receiving ITM one day after transport (ITMPRE), and a group receiving ITM two days post-infection (ITMPOST). The cattle were infected with M. haemolytica and treated with the antibiotic tulathromycin two days later. The aim was to evaluate if ITM could improve the cattle's resistance to infection and reduce clinical symptoms. One of the critical findings was that liver selenium (Se) levels were significantly higher in the ITMPRE group at two days post-infection (dpi) and in both ITM groups at five dpi compared to the control group. This increase in selenium is noteworthy because selenium, along with vitamin E, has been shown to enhance the intracellular killing ability of neutrophils, a type of immune cell, against bacteria like Staphylococcus aureus and Escherichia coli[3]. Although the current study did not measure neutrophil function directly, the elevated selenium levels suggest a potential mechanism for improved immune response. Clinical scores, which assess the severity of disease symptoms, were lower in the ITMPRE group on days one and eight dpi and in the ITMPOST group on day eight dpi compared to the control group. This indicates that ITM supplementation could reduce the severity of clinical symptoms associated with BRD. Thoracic ultrasonography, used to visualize lung lesions, also showed lower scores in the ITMPRE group at two dpi compared to both the control and ITMPOST groups, further supporting the beneficial effects of ITM when administered before infection. Interestingly, the study observed no significant differences in bacterial detection from bronchoalveolar lavage (BAL) or nasopharyngeal swabs among the groups. However, at five dpi, both ITMPRE and ITMPOST groups had higher frequencies of γδ T cells and natural killer (NK) cells in BAL compared to the control group. These immune cells play crucial roles in the early response to infections, suggesting that ITM may enhance the immune system's ability to respond to bacterial invasion. Additionally, leukocytes from the ITMPRE group produced more interleukin-6 (IL-6) in response to a specific immune stimulant before infection. IL-6 is a cytokine, a type of signaling molecule in the immune system, which plays a role in inflammation and infection responses. This elevated IL-6 production indicates a heightened state of immune readiness, potentially contributing to the improved clinical outcomes observed. Previous studies have shown that trace minerals like selenium can impact immune responses. For instance, selenium supplementation has been linked to increased intracellular bacterial killing by neutrophils[3], and injectable trace minerals have been shown to enhance antibody responses to viral vaccines in calves[4]. The current study builds on these findings by demonstrating that ITM supplementation can also enhance cellular immune responses and reduce clinical symptoms in cattle facing bacterial infections. In summary, the research from Iowa State University suggests that injectable trace mineral supplementation, particularly when administered before infection, may be an effective strategy to improve disease resistance in cattle. By enhancing selenium levels and boosting immune cell activity, ITM can potentially mitigate the severity of BRD, offering a valuable tool for managing cattle health in the face of bacterial challenges.

MedicineHealthAnimal Science

References

Main Study

1) Impact of an Injectable Trace Mineral Supplement on the Immune Response and Outcome of Mannheimia haemolytica Infection in Feedlot Cattle

Published 10th June, 2024

https://doi.org/10.1007/s12011-024-04251-z

Related Studies

2) Update on bacterial pathogenesis in BRD.

https://doi.org/10.1017/S1466252309990193

3) Relationships among vitamin E, selenium, and bovine blood neutrophils.

Journal: Journal of dairy science, Issue: Vol 73, Issue 9, Sep 1990

4) Effect of injectable trace minerals on the humoral immune response to multivalent vaccine administration in beef calves.

https://doi.org/10.2527/jas.2011-4024


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