Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
(N/A)
Non Technical Summary
Because of the segmented nature of the beef industry, cattle are often trucked long distances. While this makes most efficient use of feed and water resources as cattle move from places where non-human foodstuffs such as grass are available to places where grains are readily available (i.e. from cow-calf to feedlot segments), trucking poses a physiological stress on the animal. To avoid injuries, cattle are trucked such that they are unable to lay down, resulting in muscle fatigue. After arrival to their destination, cattle may choose not to eat or drink as much, preferring to lay down and rest. The purpose of our study is to determine if supplementing the trace mineral zinc to the diets of cattle before or after trucking can speed the recovery time after trucking, helping cattle eat and drink more quickly. This not only helps the animal, but it helps the farmer, as these cattle will gain more quickly as well, and recover weight lost during trucking.We will examine the effectiveness of zinc, a supplement that is easy to find, very low cost, and has limited toxicity risks. Zinc supports many processes in the body, including growth and health. In particular, zinc helps the muscle get the right energy, by affecting sugar metabolism in the body. This energy ultimately may help the animal be more resistant to the muscle fatigue that occurs during long distance trucking between segments of the cattle industry. We are a team of beef cattle welfare and nutrition experts, and we will work together to examine the effects of zinc fed at 100 ppm in the diet, before or after a 24 hour trucking event. We will measure markers of muscle fatigue such as serum lactate, which is produced when muscles run out of easily available energy (from sugars like glucose). We will also monitor effects of zinc on cattle feeding behavior and standing and laying time, as indicators of recovery from trucking. In our second experiment, we will examine zinc fed at 100 ppm or not supplemented, and compare cattle trucked for 8 hours (which is typical for many feeder cattle in the U.S.) and 24 hours (to be comparable to our first experiment).Our ultimate goal is to find an easy-to-implement and affordable nutritional strategy to best prepare cattle for trucking, or to best help cattle recover quickly from trucking. With over 103 million cattle in the United States and Canada, our work will be impactful across the beef industry.Knowledge gained from these studies will allow cattle producers to make simple and affordable changes to their mineral program to improve cattle response to trucking. Helping cattle recover more quickly from the discomfort and hunger associated with transit will result in healthier, more productive animals.
Animal Health Component
30%
Research Effort Categories
Basic
70%
Applied
30%
Developmental
(N/A)
Goals / Objectives
Our overall goalis to assess Zn supplementation as a tool to mitigate muscle fatigue in response to the transportation event, to speed cattle recovery after transit.Our long-term goalis to provide beef producers with easy and affordable strategies to improve welfare and production efficiency of transported cattle.Objective 1:To identify the optimum timing of Zn supplementation relative to transit to mitigate transit-induced muscle fatigue and improve cattle welfare, feed intake, and growth.Objective 2:To determine the potential of Zn supplementation to overcome greater muscle fatigue as a result of prolonged transit.
Project Methods
To achieve our objectives we will conduct transit stress experiments originating in both the U.S. and Canada. Our experiments are designed to improve our understanding of how timing and rate of Zn supplementation relative to transit stress, as well as transit duration, impact cattle well-being and production potential. In Experiment 1a, steers will be preconditioned in Canada and trucked to the U.S. for receiving. In Experiment 1b, steers will be preconditioned in the U.S. and trucked to Canada for receiving. The Ruminant Nutrition Research Center in Ames, IA, and the Lethbridge Research and Development Centre in Lethbridge, Alberta are approximately 24 hours' driving distance, accounting for rest stops for the drivers.We are capitalizing on the unique opportunity to transport cattle between two research institutions equipped to assess indicators of cattle fatigue. Replicating this experiment will strengthen interpretation and adoption of findings across North America.These experiments will be conducted as a two × 2 factorial, with two dietary concentrations of Zn (0 or 100 mg Zn/kg D.M.; supplemented as ZnSO4) and two periods of Zn supplementation relative to a 24-h transit event (42-d preconditioning period prior to transit or 56-d receiving period after transit). Eighty Angus-crossbred steers (226 kg body weight;B.W.) will be purchased from a single source and blocked by B.W. to treatment (n = 20 per treatment). Steers will be housed in pens, with five steers and one GrowSafe bunk (GrowSafe Systems, Airdrie, AB, Canada)per pen in the U.S. or ten steers and two GrowSafe bunks per pen in Canada. Individual animal will be the experimental unit. Days on study are denoted relative to the trucking event. On d -42, steers will begin a 42-d preconditioning period where half will receive no supplemental Zn (basal diet ~35 mg Zn/kg D.M.), which will meet NASEM (2016) recommendations to prevent deficiency, while the other half will receive 100 mg supplemental Zn/kg D.M. (as ZnSO4). On d 0, steers will be loaded onto a commercial semi and transported ~2200 km (~24-h) from Canada to the U.S. (Exp 1a) or U.S. to Canada (Exp 1b). Steers from Zn treatments will be stratified across truck compartments and cattle density within compartments will not exceed that recommended by the Guide for the Care and Use of Agricultural Animals in Research and Teaching. Uponarrival on d 1, half of the steers within each preconditioning treatment will begin receiving 0 or 100 mg supplemental Zn/kg D.M. (as ZnSO4) for a 56-d receiving period. As would be common in production, receiving diets will be different from preconditioning diets (more grain), but are expected to contain ~30 mg Zn/kg D.M., meeting NASEM (2016) recommendations. Every effort will be made to match diet composition at our respective institutions. At minimum, diets will be balanced for basal concentrations of Zn, energy, moisture, protein, and fiber.We will utilize acombined evaluation of physiological and behavioral indicatorsto thoroughly assess the effects oftiming of Zn supplementation relative to transiton cattle welfare. This will include: serum or plasma markers of muscle fatigue, inflammation, energy status, antioxidant status, and stress. Video and feed bunk measures will assess feeding recovery post trucking, and standing and lying time and gaits. Cattle feed intake, weight gain, and feed efficiency will be determined.Experiment 2 will utilize identical measures as outlined above. This experiment will be conducted as a 2 × 2 factorial, with two dietary Zn supplementation strategies (0 mg Zn/kg D.M. for the preconditioning period, followed by 100 mg Zn/kg D.M. for the post-transit receiving period; or 100 mg Zn/kg D.M. throughout the 99-day experiment; as ZnSO4) and two transit durations (8 or 24 h). Because this experiment will be conducted after Exp. 1a/1b, we will be able to match the time on truck for the "24 h" treatment to the time on truck for the prior experiment. Eighty Angus-crossbred steers (226 kg B.W.) will be purchased from a single source and blocked by B.W. to treatment (n = 20 per treatment). Steers will be housed in pens (5 steers per pen) equipped with one GrowSafe bunk per pen; thus, individual animal will be the experimental unit.Days on study are denoted relative to the trucking event. On d -42, steers will begin the preconditioning period and half will receive no supplemental Zn (basal diet ~35 mg Zn/kg D.M.) while the other half will receive 100 mg supplemental Zn/kg D.M. (as ZnSO4). On d 0, within dietary Zn treatments, steers will be equally assigned to a transit duration of 8 or 24 hours. Steers will be hauled in a commercial semi (one semi for 8 h and one semi for 24 h cattle), stratified across truck compartments by Zn treatment, and received back to the Iowa State University Ruminant Nutrition Research Center. Trucks will be loaded at 0700 h for 24 h cattle and 2300 h for 8 h cattle, such that unloading time will be 0700 h on d 1 for both treatments to avoid any diurnal effects on circulating markers of muscle fatigue. Steers will return to their original home pens and all steers will receive 100 mg Zn/kg D.M. for the 56-d receiving period.All continuous data for Exp. 1a, 1b, and 2 will be analyzed using the Mixed Procedure of SAS, with the fixed effects of Zn treatment in the preconditioning period (0 vs. 100 mg Zn/kg D.M.). Data from the post-trucking receiving period for Exp. 1a/1b will be analyzed as a 2 × 2 factorial design with the fixed effects of preconditioning Zn treatment (0 vs. 100 mg Zn/kg D.M.) and receiving Zn treatment (0 vs. 100 mg Zn/kg D.M.). Data from the post-trucking receiving period for Exp. 2 will be analyzed as a 2 × 2 factorial design with the fixed effects of Zn strategy (preconditioning Zn at 0, followed by receiving Zn at 100 mg Zn/kg D.M. vs. 100 mg Zn/kg D.M. in both preconditioning and receiving periods) and transit duration (8 or 24 h). Because both institutions possess GrowSafe bunks and will be capturing individual animal feed intake, as well as body weights, blood markers of muscle fatigue, and standing/lying behavior, we will be able to assess the magnitude and rate of recovery for these variables in each of our experimental animals. Steer will be experimental unit for all data (n = 40 per treatment for preconditioning periods; 20 per treatment for factorialized receiving period data).Efforts in this project will include presentation of results at scientific conferences, incorporation of results into advanced teaching curriculum, and collaboration with our extension colleagues to facilitate outreach of the results, in addition to our own established communication networks with the beef industry.The project team will meet regularly to discuss milestones, including successful completion of live animal work, laboratory analysis of video or samples collected during the live portion of the trials, and analysis of data and publication of peer-reviewed scientific articles and lay audience targeted publications sharing results of the work.