Abstract During the preconditioning and feedlot receiving phases of beef cattle production, animals undergo a variety of stressors, such as weaning, transportation, and new environments. These stressors, alone or in conjunction with one another, may lead to a decrease in animal performance. In order to mitigate this decrease in performance, producers may opt to provide trace mineral supplementation. Due to decreased feed intake exhibited during the preconditioning and feedlot receiving phases, oral trace mineral supplementation may not be effective, hence, producers may opt to utilize an injectable trace mineral (ITM) solution. However, research surrounding the production effects of such injectable products are variable. Therefore, a meta-analysis further analyzing the effects of ITM solutions on average daily gain was conducted. Studies were collected through two independent literature searches which included terms relevant to the population and intervention of interest, yielding 710 articles. After reviewing studies for eligibility based on study population, intervention, and study outcomes available, 16 studies from 12 published manuscripts remained and included within the present analysis. Data was extracted from studies as treatments means and a value within the ability to calculate standard deviations, which were then analyzed within the meta package of R (v. 4.3.2). Data was further classified based on risk classification, phase receiving, concurrent usage of oral trace mineral supplementation, length of study, and breed of animals utilized. Overall, the usage of an ITM solution did not impact animal average daily gain (ADG; P = 0.21) when compared to a saline solution. Additionally, ADG differed between risk classifications (P = 0.03) with the usage of an ITM product increasing ADG by 0.12 kg/d in high-risk animals (P = 0.02) with no effect seen in low-risk animals (P = 0.93) when compared to a saline solution. Furthermore, the usage of an ITM solution did not affect ADG within the preconditioning phase (P = 0.39) but tended to increase ADG (P = 0.09) by 0.06 kg/d within feedlot receiving. Average daily gain was unaffected by the inclusion (P = 0.49) or exclusion (P = 0.37) of concurrent oral trace mineral supplementation. Moreover, ADG was unaffected within short ( 30 days; P = 0.41) and extended ( 60 days; P = 0.74) study durations, but increased ADG by 0.07 kg/d in moderate (30-60 days; P = 0.04) study lengths. Lastly, the usage of an ITM within B. indicus cattle did not affect ADG (P = 0.42), however, ADG was increased by 0.03 kg/d (P = 0.05) within B. taurus cattle and by 0.09 kg/d (P = 0.21) within crossbred cattle. In conclusion, the usage of an ITM solution did not affect overall ADG but may increase ADG within specific production circumstances.
McKnight et al. (Wed,) studied this question.