Extension

Trace minerals have many important physiological functions in beef cattle including vitamin synthesis, hormone production, enzyme activity, collagen formation, tissue synthesis, oxygen transport, energy production, and other physiological processes related to growth, reproduction and health. Thus, trace minerals must be supplemented to beef cattle diets when forages and rations are deficient or have incorrect proportions. Traditionally, trace minerals used in animal feed have been categorized as either inorganic (primarily sulfate and oxide forms) or organic. "Organic" simply means that the mineral is bound to an organic material. These materials are generally amino acid complexes, proteinates, chelates, polysaccharide complexes, and propionates.

 

The issues associated with health and management of newly received cattle continue to pose significant animal welfare and economical challenges for the beef industry. Shipping fever, or bovine respiratory disease complex (BRD), is the most common morbidity and mortality event among feedlot cattle in the United States.¹ BRD accounts for approximately 75% of morbidity² and 50 to 70% of mortality in feedlots.³ The incidence of BRD is greater within the first days after feedlot arrival (receiving period)⁴; usually the first 4 to 8 weeks in which relocated beef cattle adjust to their new environment. University of Arkansas research investigated the effects of inorganic or complexed sources of trace minerals (zinc, copper, manganese, and cobalt) on beef heifer growth performance, morbidity, and mineral status during a receiving period.⁵

 

In this study, 287 crossbred beef heifer calves (509 lb) arriving on three delivery dates were used in a 42-day receiving trial. The heifers were obtained from a cooperating producer, who purchased calves in small groups in regional sale barns (within ~155 miles) over a period of 3 days, transporting them to a single site. Then cattle were shipped (93 miles) to the University of Arkansas Division of Agriculture Beef Cattle Research Facility near Fayetteville, AR. Heifers arrived in 3 shipment sets (block) with arrival dates of October 6, 26, and November 23, 2021. Heifers were processed after arrival, stratified by day −1 body weights (BW) and allocated randomly to eight pens (11 to 13 heifers/pen, 24 pens total). Within truckload, pens were assigned randomly to dietary treatment (12 pens/treatment).

 

Heifers were housed on 1.04-acre grass paddocks, provided ad libitum bermudagrass hay and provided dietary treatments in grain supplements fed daily. Treatments consisted of supplemental zinc (360 mg/day), copper (125 mg/day), manganese (200 mg/day), and cobalt (12 mg/day) from complexed (Zinpro Availa 4, Zinpro Corp.) or inorganic sources (sulfates). The heifers were observed daily for clinical BRD. If presenting BRD symptoms and rectal temperature ≥104°F, heifers were deemed morbid and treated with antibiotics. Six heifers/pen were bled to determine serum haptoglobin concentrations on days 0, 14, and 28. Liver biopsies were taken on day 5 ± 2 and 43 ± 1 from three calves selected randomly from each pen for mineral status comparisons.

 

These researchers reported that there tended to be a treatment by day interaction for body weights (P = 0.07). Body weights were not different on day 0 (P = 0.82) and day 14 (P = 0.36), but heifers supplemented with complexed trace mineral sources had greater body weights on day 28 (P = 0.04) and day 42 (P = 0.05). Calves receiving the complexed trace mineral sources were 9 lb heavier than those receiving inorganic sources by day 42 (Figure 1). The effect of treatment on average daily gains (ADG) are shown in Table 1. Supplementing cattle for the first 42 days after arrival with complexed trace mineral sources resulted in greater (P = 0.05) overall ADG when compared to supplementing inorganic sources (P = 0.05; 1.72 vs. 1.54 lb/day). Heifers supplemented with inorganic trace minerals had greater BRD incidence (P = 0.03; 58 vs. 46%). The source of trace mineral supplementation had no effect (P ≥ 0.20) on liver mineral concentrations and there were no treatment x day interactions (P ≥ 0.35).

 

Figure 1. Effects of complexed or inorganic trace mineral supplementation on body weights during 42-day receiving trial. Means within a day without a common superscript differ (P ≤ 0.05). Adapted from Cheek et al., 2024.

 

 

Table 1. Effect of complexed or inorganic trace mineral supplementation on growth performance of newly received calves.

 

In conclusion, in this study replacing inorganic sources of trace minerals with complexed sources of trace minerals (zinc, copper, manganese, and cobalt) improved growth performance and decreased morbidity treatments and associated medication costs during the 42-day receiving phase. The source of trace mineral supplemented had no effect on liver mineral concentrations during the 42-day receiving trial. These authors noted that “these results demonstrate the variability observed in trace mineral concentrations in liver, and highlight the continued need to better understand factors that influence liver mineral concentrations. These calves experienced stress through sale barn exposure, commingling, and transportation which may have influenced differences in trace mineral source bioavailability.”

 

¹ USDA-APHIS. 2013. Pages 18 in Feedlot 2011 Part IV: Health and Health Management on U.S. Feedlots with a Capacity of 1,000 or More Head. USDA–APHIS–Veterinary Services, Fort Collins, CO.

 

² Edwards, A. J. 1996. Respiratory diseases of feedlot cattle in the central USA. Bovine Practitioner 30:5–7.

 

³ Loneragan, G. H., D. A. Dargatz, P. S. Morley and M. A. Smith. 2001. Trends in mortality ratios among cattle in US feedlots. J. Am. Vet. Med. Assoc. 219: 1122-1127.

 

⁴ Snowder, G. D., L. D. van Vleck, L. v. Cundiff, and G. L. Bennett. 2006. Bovine respiratory disease in feedlot cattle: environmental, genetic, and economic factors. J. Anim. Sci. 84:1999–2008.

 

⁵ Cheek, R. A., E. B. Kegley, J. R. Russell, J. L. Reynolds, K. A. Midkiff, D. Galloway, and J. G. Powell. 2024. Supplemental trace minerals as complexed or inorganic sources for beef cattle during the receiving period. J. Anim. Sci. 102.