Meta-analysis of the effects of organic and inorganic zinc supplementation on performance traits and diarrhea incidence in suckling calves

This meta-analysis aimed to investigate and compare the effects of organic and inorganic zinc supplementation on performance traits and diarrhea incidence in suckling calves. A comprehensive literature search identified 15 eligible studies (<strong>published between</strong> 2019 to 2024), providing data for 44 comparisons on body weight (BW), 70 on average daily gain (ADG), 66 on total dry matter intake (TDMI), 34 on starter intake, 53 on feed conversion ratio (FCR), and 34 on diarrhea incidence. A multilevel random-effects model was employed to estimate the effect size of zinc supplementation, with the effect size expressed as the standardized mean difference (SMD). Publication bias was assessed using funnel plots and Egger