Shawn L. Archibeque

Community Structures of Fecal Bacteria in Cattle from Different Animal Feeding Operations

ABSTRACT The fecal microbiome of cattle plays a critical role not only in animal health and productivity but also in food safety, pathogen shedding, and the performance of fecal pollution detection methods. Unfortunately, most published molecular surveys fail to provide adequate detail about variability in the community structures of fecal bacteria within and across cattle populations. Using massively parallel pyrosequencing of a hypervariable region of the rRNA coding region, we profiled the fecal microbial communities of cattle from six different feeding operations where cattle were subjected to consistent management practices for a minimum of 90 days. We obtained a total of 633,877 high-quality sequences from the fecal samples of 30 adult beef cattle (5 individuals per operation). Sequence-based clustering and taxonomic analyses indicate less variability within a population than between populations. Overall, bacterial community composition correlated significantly with fecal starch concentrations, largely reflected in changes in the Bacteroidetes, Proteobacteria, and Firmicutes populations. In addition, network analysis demonstrated that annotated sequences clustered by management practice and fecal starch concentration, suggesting that the structures of bovine fecal bacterial communities can be dramatically different in different animal feeding operations, even at the phylum and family taxonomic levels, and that the feeding operation is a more important determinant of the cattle microbiome than is the geographic location of the feedlot.

The Modern Feedlot for Finishing Cattle

The modern beef feedlot has evolved into a complex system that is very dependent upon technology. Modern feedlots are organized into departments, often including the office, cattle, yard, feed milling, and feed departments, that allow for improvements in production efficiency through the specialization of management and labor. Regardless of size, feedlots must succeed at the following tasks: cattle procurement, cattle receiving, cattle processing, daily cattle observations, health treatments, cattle marketing, feed procurement, feed commodity receiving, feed commodity storage, diet formulation, diet delivery, bunk management, and environmental management. Apart from cattle ownership, feedlots create most of their gross income from feed sales, yardage, inventory gain on flaked grain, and combinations of these sources. The future of the industry is filled with economic and political challenges, including high grain prices owing to competition from the ethanol industry, environmental regulations, excess feedlot capacity, and a diminishing labor pool owing to declining rural populations.

An evaluation of 10-G brand direct-fed microbial for yearling steers fed finishing diets containing wet distillers grains12

ABSTRACT One hundred forty-four Charolais crossbred yearling steers (335.5 kg ± 12.2) were used to determine the effect of 10-G brand direct-fed microbial product (10-G contains Lactobacillus acidophilus, Enterococcus faecium, Pediococcus acidilacticii, Lactobacillus brevis, and Lactobacillus plantarum) in a finishing diet containing steam-flaked corn and wet distillers grains with solubles (WDGS) on performance and carcass characteristics. Cattle were fed twice daily with dietary treatment applied only to the first feeding. Dietary treatments included 1) 10-G (TRT) product in the first round of feeding and 2) control (CON). The CON diet received a placebo in place of the 10-G product. Each diet contained 6% wheat straw (WS) and 15% WDGS and the finishing diet contained 68% steam flaked corn on a DM basis. Prior to the initiation of the experiment, WS and WDGS were mixed together using a vertical screw-type truck-mounted mixer box in the ratio of 2:5 (kg:kg) WS to WDGS on a DM basis, stored in a single pile, packed with a tractor, and covered with plastic. The WS and WDGS mixture was added to each batch of feed as one commodity during diet manufacturing. Overall ADG, DMI, G:F, and NE recovery were similar across treatments (P > 0.10). Hot carcass weight, YG, QG, maturity, and marbling score were similar across treatments (P > 0.10). Carcasses from steers receiving 10-G had a greater (P

Effect of feed bunk management on feedlot steer intake1

Twelve pens of yearling steers were used to determine the effects of bunk management on DMI and the pattern of feed disappearance from the feed bunk. Three 0630 h target bunk scores were compared: 0 = a bunk devoid of feed particles; 1/2 = a bunk containing up to 0.25 kg of feed/steer; and 1 = a bunk containing greater than 0.25 and up to 1.0 kg of feed/steer. Steers were fed twice daily at 0700 (round 1) and 1130 h (round 2), and bunks were observed by a single observer at 1630, 2200, 0200, and 0630 h. Daily DMI for steers fed to a target score of 0 (9.74 kg) was lower (P < 0.05) than that for steers fed to a target score of 1/2 (10.37 kg), which was lower (P < 0.01) than that for steers fed to a target score of 1 (11.21 kg). In addition, a treatment-by-time interaction (P < 0.001) for the estimated disappearance of feed from the bunk suggests that eating patterns differed by treatment. Even though adequate feed was available in all bunks from 0700 until 1600 h to support similar DMI during this time period for all treatments, steers fed to a target score of 0 consumed less feed during the day (0730 until 1600 h) than did steers fed to a target score of 1/2 (P < 0.001), which consumed less feed from delivery through 1600 h than did steers fed to a target score of 1 (P < 0.01). These data indicate that slick bunk management systems may restrict DMI in feedlot steers and alter feed consumption patterns.