Trace Mineral Source and Chromium Propionate Supplementation Affect Performance and Carcass Characteristics in Feedlot Steers

Trace minerals are supplemented to finishing cattle to prevent trace mineral deficiencies. Nearly all feedstuffs are deficient in one or more trace minerals. Copper (Cu) and zinc (Zn) are the trace minerals most likely to be deficient. Hydroxychloride (HTM) and sulfate trace minerals (STM) differ in their bioavailability and effect on rumen fermentation. Research has shown that hydroxy forms of copper and zinc are relatively insoluble at neutral or slightly acidic pH ranges (rumen pH) and increase in solubility as pH decreases (abomasum and early small intestine), whereas sulfate forms of copper and zinc are almost completely soluble at neutral to slightly acidic pH ranges.^{1, 2}

 

Copper and zinc hydroxychloride have been shown to be more bioavailable than sulfate forms. In addition, steers supplemented with Cu, manganese (Mn), and Zn from HTM had greater neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility and greater total volatile fatty acid (VFA) concentrations than those receiving sulfate sources when fed diets high or moderately high in fiber.³ Few feedlot studies have compared the performance of finishing cattle fed HTM sources of Cu, Mn, and Zn compared to equal concentrations of STM sources of Cu, Mn, and Zn. The data available suggest that performance is similar in feedlot cattle fed the same concentration of Cu, Mn, and Zn from HTM versus STM sources.⁴

 

Chromium (Cr) is a trace mineral required in low concentrations to enhance insulin activity. Chromium propionate (Cr Prop) is the only Cr source currently permitted by the FDA for addition to cattle diets and can be added at concentrations up to 0.5 mg Cr/kg of dry matter (DM). Recently published research tested the effect of trace mineral source (HTM vs. STM) and supplemental Cr propionate on the performance and carcass characteristics of finishing steers.⁵

 

In this study, 400 Angus-crossbred steers (815 lb) were blocked by body weight (BW) and randomly assigned within block to treatments in a 2 X 2 factorial arrangement, with factors being: 1) Trace mineral source (STM or HTM) and 2) Cr supplementation (0 or 0.25 mg Cr/kg DM, -Cr or +Cr, Treatments consisted of the addition of: 1) sulfate trace minerals (STM; 90, 40, and 18 ppm DM of Zn, Mn, and Cu, respectively), 2) STM and 0.25 mg Cr/kg DM from Cr Prop, 3) hydroxychloride trace
minerals (HTM; 90, 40, and 18 ppm DM of Zn, Mn, and Cu, respectively), and 4) HTM and 0.25 mg Cr/kg DM from Cr Prop. respectively). Each treatment consisted of 10 replicate pens with 10 steers per pen. Body weights were obtained on consecutive days at the initiation and termination of the 154-day study. Steers were fed a steam-flaked corn-based finishing diet. Ractopamine hydrochloride was fed for the last 31 days of the study. The steers were slaughtered at the end of the study and individual carcass data were collected.

 

The effects of chromium supplementation and trace mineral (TM) source on performance of the steers is shown in Table 1. Average daily gain (ADG) , dry matter intake (DMI), and Gain:Feed ratio were not affected by a TM source x Cr interaction. Steers supplemented with Cr exhibited 4.0% greater ADG (3.92 vs. 3.77 lb/day; P = 0.03) and a 4.7% improvement in Gain:Feed (0.179 vs. 0.171; P = 0.02) compared to steers not supplemented with Cr. Feed intake was not affected by Cr supplementation. Gain efficiency and DMI were not affected by TM source, but ADG tended (P = 0.12) to be greater for steers receiving HTM compared to those supplemented STM (3.90 vs. 3.79 lb/day).

 

Table 1. Main effects of chromium supplementation and trace mineral source on performance of feedlot steers. Adapted from Spears et al., 2024.

 

The effects of chromium supplementation and TM source on carcass characteristics of the steers is shown in Table 2. None of the carcass characteristics were affected by a TM source x Cr interaction. Hot carcass weight (HCW), dressing percentage, ribeye area, and USDA Yield Grade were greater (P = 0.04) in steers supplemented with HTM than in those receiving STM. Dressing percentage and ribeye area were greater (P = 0.04) and HCW tended (P = 0.06) to be greater for steers supplemented with Cr. Yield grade was not affected by Cr supplementation. Marbling score and fat thickness were not affected by treatment.

 

Table 2. Main effects of chromium supplementation and trace mineral source on carcass characteristics of feedlot steers. ^aMarbling score; 700 = moderate, 600 = modest, 500 = small, 400 = slight. Adapted from Spears et al., 2024.

 

These researchers concluded that the results of this study indicate that finishing steers supplemented with hydroxychloride sources of Zn, Cu, and Mn had greater HCW, dressing percentage, and ribeye area than those receiving sulfate sources. Steers supplemented with 0.25 mg Cr/kg DM, from Cr Prop, had greater ADG, dressing percentage, and ribeye area, and improved gain efficiency compared those not receiving Cr. Responses to chromium supplementation were not affected by trace mineral source.

 

¹ Spears, J. W., E. B. Kegley, L. A. Mullis. 2004. Bioavailability of copper from tribasic copper chloride and copper sulfate in growing cattle. Anim. Feed Sci. Technol. 116:1–13.

 

² Genther, O. N., and S. L. Hansen. 2015. The effect of trace mineral source and concentration on ruminal digestion and mineral solubility. J. Dairy Sci. 98:566–573.

 

³ Caldera, E., B. Weigel, V. N. Kucharczk, K. S. Sellins, S. L. Archibeque, J. J. Wagner, H. Han, J. W. Spears, and T. E. Engle. 2019. Trace mineral source influences ruminal distribution of copper and zinc and their binding strength to ruminal digesta. J. Anim. Sci. 97:1852–1864.

 

⁴ Caldera, E., J. J. Wagner, K. Sellins, S. B. Laudert, J. W. Spears, S. L. Archibeque, and T. E. Engle. 2017. Effects of supplemental zinc, copper, and manganese concentration and source on performance and carcass characteristics of feedlot steers. Prof. Anim. Sci. 33:63–72.

 

⁵ Spears, J. W., H. Y. Loh, K. E. Lloyd, J. S. Heldt, and T. E. Engle. 2024. Trace mineral source and chromium propionate supplementation affect performance and carcass characteristics in feedlot steers. J. Anim. Sc. 102. Available at:
https://doi.org/10.1093/jas/skae106