A double-blind block randomized clinical trial on the effect of zinc as a treatment for diarrhea in neonatal Holstein calves under natural challenge conditions

Abstract

Diarrhea is the leading cause of death in neonatal calves and contributes to major economic losses. The objective of this double-blind randomized clinical trial was to evaluate the effect of oral inorganic or organic zinc supplementation as a treatment for neonatal diarrhea in calves. Seventy nine 1 to 8 day old male Holstein calves on a California calf ranch were block randomized to one of 3 treatments within 24h from their first onset of diarrhea. Calves received a daily dose of either a placebo composed of 80 mg of zinc-free powder, 381.54 mg of zinc methionine (Met) (equivalent to 80 mg of zinc), or 99.69 mg of zinc oxide (ZO) (equivalent to 80 mg of zinc) in 2L of a zinc-free oral rehydration solution (ORS). Calves were treated once daily until normal fecal consistency or for a maximum of 14 days. Upon enrollment and exit, calves were weighed, and blood, feces, and liver biopsies were collected for trace mineral analysis. Fecal samples at enrollment and exit were tested for E. coli K99, Cryptosporidium spp., rotavirus and coronavirus. Pre-treatment liver zinc concentrations for the 71 calves in the placebo, zinc Met, and ZO treatment groups were 710.6 (SEM=147.7), 852.3 (SEM=129.6), and 750.7 (SEM=202.9)mg/kg dry weight (DW), respectively. Exit liver zinc concentrations for the calves in the placebo, zinc Met, and ZO treatment groups were 728.9 (SEM=182.9), 1141.0 (SEM=423.8), and 636.8 (SEM=81.5)mg/kg dry weight, respectively. Although statistically non-significant, there were clinically important findings identified for each of zinc Met and ZO treatments. Calves treated with zinc Met gained on average 40 g/day during a diarrhea episode compared to a weight loss of 67 g/day on average in the placebo-treated calves (Power 19.9%). Calves treated with ZO had 1.4 times higher hazard of clinical cure compared to calves in the placebo group (Power 5.3%). Calves that were fecal positive to cryptosporidium spp. at enrollment and treated with zinc Met had higher odds of testing negative at exit compared to placebo calves (Odds Ratio (OR)=16.0). In contrast, calves treated with ZO tended to recover (fecal score=1) one day earlier compared to calves treated with a placebo (8.5 d vs. 9.7 d). The current trial identified clinically important findings that warrant further research to investigate zinc's therapeutic effect for calf diarrhea.

Effectiveness of zinc supplementation on diarrhea and average daily gain in pre-weaned dairy calves: A double-blind, block-randomized, placebo-controlled clinical trial

“…107 g between treatment groups (Stata, College Station, TX). After allowing for 15% attrition and assuming 50% incidence of diarrhea based on study authors expert opinion, and a difference in ADG of 107g [11], a sample size of 500 calves per treatment group (n = 1500 total) was deemed required.…”

“…Zinc supplementation in children decreases the incidence, duration, and severity of diarrhea, increases recovery rates, decreases the use of antibiotics and antidiarrheal medications, and reduces mortality [5][6][7][8][9][10]. In a clinical trial that established a non-toxic zinc dose and investigated its therapeutic use for diarrhea in neonatal dairy calves, zinc-treated calves had numerically quicker clinical recovery, increased weight gain, and higher odds of fecal clearance of Cryptosporidium parvum between diarrhea onset and recovery compared with placebotreated calves [11]. As a result, zinc supplementation may be beneficial for prevention of diarrhea in dairy calves and, thus, minimize antimicrobial use.…”

“…Zinc supplementation delayed diarrhea and expedited diarrhea recovery in pre-weaned calves. Additionally, zinc improved weight gain differentially in bulls compared to heifers, indicating a research need for sex-specific dosing.Results of a previous zinc clinical trial [11] indicated that a sample size of 213 diarrheic calves per group (α = 0.05, β = 0.10, power 90%) would be needed to show a difference in ADG of Effect of zinc on diarrhea in calves PLOS ONE | https://doi.Prior to the trial, total daily dietary zinc consumed by calves during the first 14 days of life was estimated using heavy metal analysis of water (n = 2), calf milk (n = 2), two types of oral electrolyte solutions (n = 2), calf starter grain (n = 2), and an estimated intake of starter grain by calves less than 14 days of age [20,21]. Analysis was performed at the California Animal Health and Food Safety System's (CAHFS) Toxicology Laboratory (Davis, CA) by ICP-MS Effect of zinc on diarrhea in calves PLOS ONE | https://doi.org/10.1371/journal.pone.0219321 July 10, 2019 3 / 221 First diarrhea defined as the first day post-enrollment with fecal score greater than 1.2 Treatments: placebo = 0.44 g fresh milk replacer powder (MRP); zinc methionine = 80 mg of zinc (0.45 g zinc methionine complex as Zinpro180) in 0.44 g of fresh MRP; zinc sulfate = 80 mg of zinc (0.22 g zinc sulfate monohydrate) in 0.44 g of fresh MRP.1 Clinical diarrhea cure is defined as the second consecutive day of normal feces (fecal score of 1) following the first diarrhea episode.2 Treatments: placebo = 0.44 g fresh milk replacer powder (MRP); zinc methionine = 80 mg of zinc (0.45 g zinc methionine complex as Zinpro180) in 0.44 g of fresh MRP; zinc sulfate = 80 mg of zinc (0.22 g zinc sulfate monohydrate) in 0.44 g of fresh MRP.…”

“…Results of a previous zinc clinical trial [11] indicated that a sample size of 213 diarrheic calves per group (α = 0.05, β = 0.10, power 90%) would be needed to show a difference in ADG of Effect of zinc on diarrhea in calves PLOS ONE | https://doi.…”

Dose–responses of zinc–methionine supplements on growth, blood metabolites and gastrointestinal development in sheep

“…Glover et al. () demonstrated that neonatal Holstein calves treated with a total daily dose of 80 mg of Zn (381.54 mg of Zn‐Met) did not exhibit clinical or laboratory evidence of Zn toxicity or mineral deficiency.…”