PSIII-7 Late-Breaking: Improving Heifer Development Programs Using Precision Supplementation

Abstract

Abstract Improving individual animal efficiency is important for livestock producers to run financially sustainable operations. Developing heifers to replace a cow in the herd is expensive and reducing costs during the growing and reproductive phases is critical to increase profitability. Precision livestock management technologies can help reduce feed waste and optimize individual animal intake on extensive rangeland systems. Precision supplementation for heifer development programs aims to provide proper nutrition management and develop heifers to meet target body weight without over or under conditioning. With conventional feeding methods, animals are able to over consume feed and may be overdeveloped. Therefore, the objective of our study was to compare differences in yearling heifer performance between conventional and precision supplementation on winter rangeland pastures. The study was conducted at the South Dakota State University Cottonwood Field Station, located near Philip, SD. Angus heifer calves (Bos taurus, n = 60) born in the spring of 2021were utilized for the project. Following fall weaning, initial weight was used to randomly assign heifers to one of two treatments: control (n = 30) or precision (n = 30). Treatment groups were separated into different pastures to graze dormant native range from November to June and were rotated monthly to reduce pasture influence. Both groups were offered 2.27 kg/hd/d dried distillers grain pellets; the control group was bunk fed, allowing for normal variation in consumption and the precision group was fed individually using the Super SmartFeed Producer. Individual daily BW was measured using SmartScale technology and used to calculate daily rate of gain. Heifers were supplemented to reach 60% of their mature body weight (MBW; 635 kg) at time of breeding. Heifers were bred in June using estrus synchronization with fixed time artificial insemination. Statistical analysis was conducted in Program R, which included an ANOVA to evaluate the differences in ADG between the control and precision treatments. Our results indicated a significant difference in average daily gain between the control (P < 0.05), mean ADG of 1.94 and 1.76 lb/d, respectively. Further, the control group utilized 5,600 lb more feed compared to the precision group. The number of heifers that achieved estrous was similar for both control (27) and precision groups (25) based on visual qualitative assessment of heat detection patches. At completion of the winter grazing season, the control group was developed to 64.9% MBW with an average weight of 909.37 lb and the precision group reached 62.2% MBW with an average weight of 870.37 lb. Successful implementation of precision supplementation has the potential to develop more uniform heifers at breeding, reduce intake variation, and reduce supplement overconsumption.