Bovine appeasing substance: A meta-analysis of the effects on production, health, and stress indicators in growing cattle

Objective

Our objective was to use meta-analytical methods to evaluate the effectiveness of treating growing cattle with bovine appeasing substance (BAS) to improve production, health, and stress indicators.

Materials and Methods

A search of 3 search engines identified experiments that examined the effectiveness of treating growing cattle with BAS to improve production, health, and stress indicators. Results of experiments were evaluated to ensure that these were from peer-reviewed journals or theses published in English, were in vivo and evaluated use of BAS, were randomized, had appropriate analysis of data, and contained data to determine the effect size for outcomes. The standardized mean difference was estimated for continuous data and risk difference between groups for dichotomized disease data. Multilevel models were used when experiments were nested within studies. Publication bias was assessed through funnel plots. The potential influence of pseudo-replication and duration of experiment were assessed through meta-regression.

Results and Discussion

A total of 13 studies with up to 18 experiments were included. There was no significant difference in initial BW or evidence of publication bias for any outcome. For stress outcomes, only blood cortisol was reduced by treatment by 3.85 ng/mL (95% CI: −7.60 to−0.09), supporting the proposed mode of action of BAS, but did not result in overall production or health benefits, including hair cortisol. However, there were positive point directions and results in some individual experiments, particularly for final BW, mortality, and virus antibodies. The limited number of experiments and large variation in study design prevented extensive exploration of potential sources of heterogeneity.

Implications and Applications

The reduction in blood cortisol concentrations by BAS indicates its potential to mitigate the effects of routine animal husbandry stress on cattle. Positive, but nonsignificant, point directions for final BW, mortality, and virus antibodies suggest the need for more experiments to determine whether the intervention can be justified on a cost-efficacy or ethical basis.