Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Hector Manuel Menendez


The Great Plains supports about 40-50% of beef cattle production in the United States. Consequently, the beef cow-calf sector provides a large economic impact for states located within the Northern Great Plains (South Dakota Department of Agriculture, 2021). Producing profitable rangeland beef cattle through an economically efficient cowcalf operation presents several challenges. These challenges include providing adequate nutrition to meet the needs of growing heifers on rangelands, which requires additional labor and feed/supplement to achieve desired rates of gain and reach a target body weight, resulting in reproductive success. Implementation of precision livestock technology (PLT) and the use of precision system models (PSM) to manage cattle and provide adequate nutrition and growth is one viable option for developing heifers in an efficient manner. Thus, our first objective was to deploy and train western South Dakota weaned heifers to use two PLT systems, the SmartScaleTM and Super SmartFeed ProducerTM (C-Lock Inc., Rapid City, SD), and our second objective was to develop a PSM to dynamically adjust supplement intake every two weeks. The first study consisted of deploying two PLTs (SmartScaleTM and Super SmartFeed ProducerTM) at the South Dakota State University Cottonwood Field Station, located near Philip, SD. Sixty black Angus heifers (n=60; 237.6 ± 15.5 kg) grazed dormant native range from November 2021 to May 2022 and were supplemented Dakota Gold DDGS (POET, Sioux Falls, SD); control heifers (n = 30) were supplemented in a bunk and precision heifers (n=30) were supplemented on an individual basis via the Super SmartFeed ProducerTM. Results of this study indicate cost savings of $28/hd for supplement for the precision treatment. There was a significant difference in supplement intake (P < 0.01) and final BW (P = 0.01) between treatment groups. Average daily gain (ADG) differed between treatments in the months of November 2021 (P = 0.371), February 2022 (P < 0.01) and April 2022 (P < 0.01). No differences were reported for pre-pubertal cyclicity (P = 0.227) or conception rates (P = 0.142). Although we did not see increases in reproduction rates for the precision supplement treatment, we did see an increase in supplement cost savings and were better able to develop heifers to meet a target BW with less variation in final BW across the group, while reducing supplement consumed by animals. The second study included the development of a PSM, the Range Cattle Supplement Allotment model (RCSAmodel), which dynamically adjusts supplement intake for individual animals based on several factors, including body weight (BW, kg), current average daily gain (ADG, kg/d) and a target BW (381 kg). We completed this by developing RCSAmodel, using real-time animal performance data, nutrient and growth equations, and by developing a supplement optimization model. All these components made up the RCSAmodel, which was used to compare observed heifer intake with what the optimized model said should have been supplemented. Results of this comparison indicated three main trends for heifers: over-, under-, or adequately supplemented; additional analysis identified that heifers were over and under supplemented 69% and 31% of the time when supplemented, respectively. There was a significant difference (P < 0.01) in performance gap (ADG) between control (0.39 ± 0.05 kg/d) and precision (0.13 ± 0.05 kg/d) groups. Precision livestock technology appears to be a feasible tool for rangeland beef cattle producers to use for developing heifers to reduce time spent feeding cattle, and has the potential to decrease over consumption of supplement, leading to supplement cost savings. The use of the RCSAmodel is likely to enhance the utility of PLT because it can fully leverage big data that can be received, and used, by producers, leading to optimized individual precision supplementation. The use of PLT and development of PSMs, like precision weighing and supplementing and the RCSAmodel, can lead to advancements in rangeland cattle research. Ultimately, systems will improve over time, allowing producers to implement the technology and receive information in real-time, which is a critical first step to applying precision livestock farming to extensive rangelands.


South Dakota State University

Included in

Beef Science Commons



Rights Statement

In Copyright