Beef cattle follow a daily, cyclical pattern of grazing, rumination, and digestion that coincides with their environment and season. Traditionally backgrounding operations hand feed any supplement in the morning. However, this practice may interrupt typical grazing patterns during early morning and subsequent rumination during the heat of the day. Self-fed concentrate feeds containing intake limiters are used to minimize the labor associated with hand feeding and allow cattle to eat throughout the day. The objectives of this experiment were to investigate the effect of supplement feeding time on performance and grazing behavior of backgrounded beef steers. Crossbred beef steers (n = 54; 7 ± 1 m of age; body weight, BW = 243 ± 2 kg) were sourced from a regional cattleman's association and grazed on tall fescue pasture (Festuca arundinacea) at the Southwest Virginia Agricultural Research and Extension Center in Glade Spring, VA from October 1 to November 7, 2019. Cattle were stratified by BW and source and allotted to 9 pasture groups (6 steers per pasture) in a randomized design. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Cattle were weighed on 2 consecutive days at the start and end of the experiment, and feed adjustments were made following three interim weigh-ins. Motion-sensing cameras were used to monitor cattle visits to the feeder and waterer portions of the pasture. Treatment did not impact (P = 0.13) BW, flesh condition score (FCS), dry matter intake (DMI), average daily gain (ADG), and backfat thickness. SELF steers were significantly more feed efficient than the AM supplemented groups (P = 0.03) and tended to be a greater G:F ratio (P = 0.08) for the PM supplemented groups vs. AM supplemented steers. Steers with access to a self-feeder showed behavioral differences to hand supplemented cattle, with more feeder visits in a 24 h period (P = 0.01) compared to AM and PM steers. Despite these behavioral observations, any disruption in natural grazing behavior was not dramatic enough to negatively influence backgrounded cattle growth performance. / Master of Science / Grazing beef cattle tend to follow a general pattern of grazing, rumination, and digestion that coincides with their environment and the time of year. Backgrounded cattle managed in pasture-based systems are traditionally offered supplemental feedings in the morning. However, this practice could be decreasing how efficiently cattle utilize forage resources. Natural grazing behaviors are more intense preceding the heat of the day and interruption of morning grazing bouts could decrease forage intake by causing cattle to come to the feeder to consume supplement feedings. To examine how feeding time potentially influences performance and grazing behavior of backgrounded beef cattle, 52 crossbred beef steers 7 to 8 months of age and weighing 243 kg were grazed on tall fescue pastures at the Southwest Virginia Agricultural Research and Extension Center from October 1 to November 8, 2019. Cattle were supplemented with either a commodity blend or cracked corn mixed with an intake limiter. Cattle were sourced from 4 local producers and allotted to 9 pastures by body weight (BW) and source. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Adjustments were made to the average BW of pasture groups, following three interim weigh dates at d 11, d 21, and d 30, to keep intake levels accurately at 1.5% BW. Flesh condition scores (FCS) were assigned on a scal of 1 to 9, with 1 considered emaciated and 9 excessively fat. 12th rib fat thickness (FT) was measured using an Aloka 500SC ultrasound. Both measurements were taken on the first and final day of the experiment. Motion-sensing cameras were installed in each pasture to capture pictures every one-minute following motion detection. Subsequent pictures were used to analysis the number of feed and water visits, along with time of day, in an attempt to characterize intake behavior. There were no major differences seen by treatment groups for BW, flesh condition score, DMI, ADG, and backfat thickness. Cattle on the SELF treatment had greater G:F than AM, with PM cattle being intermediate and not different than either. Steers with access to a self-feeder visited the feeder more than double the number of times in a 24 h period than either of the hand supplemented group. Despite differences in observed cattle behavior, any disruption in natural grazing behavior did not negatively influence performance of backgrounded steers.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/98826 |
| Date | 11 June 2020 |
| Creators | Claire, Olivia Mary |
| Contributors | Animal and Poultry Sciences, Wilson, Thomas Bain, Greiner, Scott P., Mercadante, Vitor R. G. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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