Recipient Organization
OKLAHOMA STATE UNIVERSITY
(N/A)
STILLWATER,OK 74078
Performing Department
Animal Science
Non Technical Summary
Oklahoma currently ranks in the top 5 cattle-producing states for all cattle and calves. Cattle are the number one agricultural commodity in Oklahoma, with cash receipts in excess of $3 billion annually (NASS, 2020). Bovine respiratory disease (BRD) is the most significant production problem for the beef industry, accounting for the majority of morbidity, mortality, and decreased production in feedlot cattle with estimated annual economic losses in excess of $2 billion (Powell, 2013). The disease is an extremely complex illness complicated by a multitude of stressors, viruses, and bacterial pathogens that can potentially contribute to its onset (Duff and Galyean, 2007; Griffin et al., 2010). At its core, BRD is a viral and bacterial disease of the respiratory tract. However, risk factors including various stressors can suppress the calf's immune system, allowing for these viral and bacterial pathogens to rapidly multiply within the animal's respiratory tract. Aich et al. (2009) defined these stressors as "a psychologically perturbing condition occurring in response to adverse external influences capable of affecting physical health." These risk factors or stressors occur most frequently after calves are removed from their dams, which is commonly referred to as "weaning." Loerch and Fluharty (1999) consider this process to be the single most fatiguing event in the life of a feeder calf. The way cattle are marketed in the U.S. is inherently responsible for a variety of stressors. In the Southern Plains and Southeast U.S., calves are commonly removed directly from their dams and shipped to a livestock market for sale. At the livestock market, calves are commingled with many other cattle of unknown disease and vaccination status. Calves are typically purchased and again commingled into large lots to be loaded on trucks for transportation. The calves are then transported long distances where they are potentially exposed to additional stressors such as exhaust fumes, extreme temperatures, dehydration, malnourishment, and exhaustion (Griffin et al., 2010). Once calves arrive at the feedlot or are received into a stocker or backgrounding program, additional stressors then occur. These post-marketing stressors include processing, which typically includes the administration of vaccinations and implants, and potentially includes dehorning and castration, additional sorting and commingling to form uniform pens, exposure to dusty pen environments, and the introduction to new feed and unfamiliar water sources. All of these stressors serve to negatively affect the immune system at a time when the calf is likely going to be exposed to viral and bacterial respiratory pathogens. The beef industry has investigated the use of feed additives and nutritional supplements in an attempt to improve performance and immune response of calves during these periods of stress and pathogen exposure. One such group of nutritional supplements that have received much consideration are trace minerals (TM). Although TM makes up less than 0.01% of the total mass of an organism and are required in extremely small amounts within the diet, many TM is essential for proper growth, development, and immune function. Trace mineral requirements are not well defined, and deficiencies are difficult to isolate due to the inconspicuousness of deficiency signs and the complex interactions that exist within mineral metabolism. Stress-induced TM deficiencies have been reported in calves and can be evident during the receiving period. This is especially true as feed intake levels in calves average only 1.5% of body weight during the first 14 days after arrival at the feed yard (Galyean and Hubbert, 1995). The supplementation of TM has been demonstrated to alter immune function measurements and reduce morbidity associated with BRD in some cases (Galyean et al., 1999). However, other experiments have shown no improvement in performance or health variables from the supplementation of TM. Overall, TM research has been very inconsistent when investigating the ideal concentrations and sources of TM supplementation needed for optimum results. In addition to the critical receiving period, TM supplementation has been reported to impact the performance and carcass characteristics of finishing cattle as well. Ahola et al. (2005) examined the effects of lifetime Cu, Zn, and Mn supplementation from organic and inorganic sources on the performance, mineral status, immunity, and carcass traits of feedlot cattle. The authors reported that feed efficiency was altered by TM source and that cattle supplemented with TM had greater liver Cu concentrations and liver Mn concentrations compared to cattle not supplemented with TM. Ahola et al. (2005) concluded that lifetime supplementation and source of Cu, Zn, and Mn had a limited impact on the performance, health, and carcass characteristics of feedlot cattle when TM was not deficient in the diet, but also mentioned that the combined effects of lifetime TM supplementation and TM source on feedlot performance, mineral status, health, and carcass traits have not been well documented in the literature. While TM supplementation is essential, the ideal concentrations for supplementation in feedlot diets are still debated. The industry commonly supplements TM at levels 2 to 4 times above published requirements (NASEM, 2016). According to Samuelson et al. (2016), the majority of consulting feedlot nutritionists recommend feeding TM at levels in excess of NASEM (2016) requirements. It is unknown if this overfeeding is due to compensation for unknown TM status at the time of arrival or a real or perceived improvement in animal health or performance. The goals of the planned research closely match the objectives of both state (e.g., Oklahoma's Division of Agricultural Sciences and Natural Resources [DASNR] Focused Initiative) and national (e.g., United States Department of Agriculture) organizations. The overall goal of the planned research will be to improve the efficiency of beef production by positively impacting calf health and performance in the feedlot phase of production. The specific project goals are to determine the effect of supplementation with varying levels of trace minerals [including but not limited to copper (Cu), manganese (Mn), and zinc (Zn)] on the feed efficiency, average daily gain, and clinical health of beef cattle during the receiving and finishing phases of production.
Animal Health Component
85%
Research Effort Categories
Basic
15%
Applied
85%
Developmental
(N/A)
Goals / Objectives
Goal/Objective: To determine the effect of supplementation with varying levels of TM (including but not limited to Cu, Mn, and Zn) on the feed efficiency, average daily gain, and clinical health of beef cattle during the receiving and finishing phases of production.In beef cattle production, there is a continuing need to increase animal performance and improve animal health. While supplementation of TM is not a new management practice, it is becoming increasingly common to include selective TM such as Cu, Mn, and Zn in feedlot diets at levels that exceed published nutrient requirements (Samuelson et al., 2016). It has been well established that certain TM is essential for overall performance and immune function. In addition to general health and immune function mechanisms, supplementation of TM has been demonstrated to alter specific immune function measurements and reduce morbidity associated with BRD in some cases (Galyean et al., 1999). Supplementation of TM, including Cu, Mn, and Zn, has been a longstanding management practice within the feedlot industry to avoid unwanted deficiencies and to promote maximum animal performance. In addition, there is some evidence suggesting these TM play an important role in the clinical health and immune function of calves. However, the published research concerning the supplementation of Cu, Mn, or Zn at levels greater than published requirements has produced inconsistent results to date. Research on the effects of varying concentrations of TM during the receiving and finishing periods is needed to quantify whether supplementing TM in excess of published requirements can impact feed efficiency, average daily gain, and clinical health of beef cattle. The results of this research could allow beef producers to improve production efficiency and positively impact animal health. If the improved performance of calves and benefits to clinical health is realized during the receiving or finishing phases, as a result of elevated TM supplementation, this could result in healthier calves and overall improvements in the production efficiency and improved economic and environmental sustainability of beef.Hypothesis: We hypothesize that feeding elevated levels of TM, including Cu, Mn, and Zn, during the receiving and finishing phases will positively impact the clinical health and improve the performance of stressed calves.OBJECTIVES: The objective is to determine the effect of supplementing elevated levels of TM (Cu, Mn, and Zn) on the feed efficiency, average daily gain, and clinical health of beef cattle during the receiving and finishing phases of production.
Project Methods
Cattle and Experimental TreatmentsTwo hundred and forty calves (BW = 250 to 350 kg) of similar genetic makeup will be procured and delivered to the Willard Sparks Beef Research Center (WSBRC). Individual shrunk BW will be obtained at arrival, and each calf will be tagged with a unique individual ear tag. After 24 to 48 hours of rest, routine processing will occur including: obtaining an initial body weight for the experiment, treatment for internal and external parasites, vaccination against clostridial toxins, IBR, PI3, BRSV, and BVD type I and II, and administration of a growth-promoting implant. Prior to processing, calves will be ranked by arrival BW and randomly assigned to 48 feedlot pens that will have been previously assigned to a negative control treatment (CON; no supplemental TM provided in addition to the basal diet), a positive control treatment (1X; addition of supplemental TM to the basal diet at published requirements in addition to any TM present in the basal diet), a supplemental TM experimental treatment fed at 2 times the published requirements (2X; addition of TM to the basal diet at 2 times the published requirements in addition to any TM present in the basal diet) or a supplemental TM experimental treatment fed at 4 times the published requirements (4X; addition of TM to the basal diet at 4 times the published requirements in addition to any TM present in the basal diet). Calves will be assigned to 48 pens (5 animals/pen; 12 pens/experimental treatment). Calves will remain on the experimental TM treatments for the duration of the experiment.Calves will be fed to meet or exceed NASEM (2016) requirements with the exception of TM in the negative control diet. Animals on the negative control diet will still receive TM through basal diet ingredients. The animals in this experiment will not be fed a purified or TM-free diet. All diets will contain a supplement containing monensin and tylosin. The negative control group will be fed a typical growing ration for beef cattle and the experimental treatments will consist of the same ration accompanied by additional TM. All ration ingredients will be added to a Roto-Mix feed wagon and allowed to mix for 4 minutes before delivering each treatment to their respective pens. Ration samples will be obtained weekly for dry matter determination. Weekly samples will be composited for subsequent nutrient analysis.Feeding, Body Weight, and Harvest Data CollectionAll calves will be fed experimental diets twice daily beginning at 0700 and 1300. Feed will be called each morning at 0600 and pens will be fed to achieve maximum dry matter intake. Experimental treatments will be color-coded and all personnel except for Dr. Wilson and the WSBRC Research Coordinator will be blinded to the treatments. Individual body weights will be recorded on d 0, 14, 28, and every additional 28-d until the cattle are harvested. On days when cattle are weighed, the rejected feed will be collected from each pen's bunk and weighed in order to determine the total feed intake for the pen over the preceding 28-d period. Individual body weights will be used to calculate average daily gain. Average daily gain and feed intake data will be used to calculate feed efficiency. Carcass data will be collected by trained personnel at harvest.Calf Health Monitoring, Antimicrobial Treatment Criteria, and Data CollectionCalves will be monitored daily by trained evaluators throughout the study for clinical signs representative of BRD. The evaluation will use criteria based on the DART™ system (Pharmacia Upjohn Animal Health, Kalamazoo, MI) with some modifications described by Step et al. (2008). The subjective criteria utilized for pulling calves consist of depression, abnormal appetite, and respiratory signs. Signs of depression include but are not limited to: depressed attitude, lowered head, glazed or sunken eyes, slow or restricted movement, arched back, difficulty standing or walking, knuckling of joints or dragging toes when walking, and stumbling. Signs of abnormal appetite can include: an animal that is completely off feed, an animal eating less than expected or eating extremely slow, a lack of gut fill or gaunt appearance, and obvious bodyweight loss. Respiratory signs include labored breathing, extended head and neck (in an attempt to breathe), and audible noise when breathing.Evaluators will assign calves a severity score of 1 to 4 based on clinical signs and the severity of those signs. A score of 1 will be assigned for mild clinical signs, 2 for moderate clinical signs, 3 for severe clinical signs, and 4 for a moribund animal. For a calf to be assigned a score of 4, the calf would not be able to rise, or has extreme difficulty standing, walking, or breathing. These animals require immediate assistance. The objective criteria used to determine if antimicrobial treatment is needed is rectal temperature. Any animal with a severity score of 1 or 2 and a rectal temperature of 40°C or greater will receive an antimicrobial according to label instructions. Any animal with a severity score of 3 or 4, will receive an antimicrobial according to label instructions regardless of rectal temperature.Antimicrobials will be administered in the neck following Beef Quality Assurance Guidelines (NCBA, 2001) via a subcutaneous injection. The first antimicrobial treatment will be administered in the left neck, and subsequent injections will be given on alternating sides of the neck. Prior to antimicrobial administration, accurate body weight will be obtained to calculate the appropriate dosage and a blood sample will be collected. If a calf does not meet the subjective severity score and temperature criteria, no antimicrobial treatment will be administered. The severity score, temperature, body weight, and antimicrobial dosage administered (or no treatment administered) will be recorded for every calf that was examined for exhibiting clinical signs of BRD.Calf Mineral BalanceOn each weigh day through d 56 and the last weigh day prior to harvest, a blood sample will be obtained via jugular venipuncture using a TM free vacutainer tube for subsequent serum mineral analysis from a subset of calves (1 animal/pen; 12 animals/treatment). After collection, the whole blood sample will be allowed to clot for 24 hours in a laboratory refrigerator at 4°C. After the clotting time, chilled blood samples will be centrifuged at 2,500 × g for 20 minutes. Serum will be aliquoted to 2 ml microcentrifuge tubes and immediately frozen at -20°C until further analyses can be completed. Serum samples will be analyzed for TM content.On d 0, 28, 56 and the last weigh day prior to harvest, a liver sample will be obtained via liver biopsy for subsequent liver mineral analysis from the same subset of calves (1 animal/pen; 12 animals/treatment). After collection, liver samples will be sent off for TM analysis or immediately frozen at -20°C until further analyses can be completed.Statistical AnalysesData will be analyzed using SAS 9.4 (SAS Institute, Cary, N.C.). A randomized complete block design will be utilized for this experiment, blocking by initial BW within cattle source. The pen will serve as the experimental unit.