Kansas Feedlots Research Articles

Bacteria resistant to ciprofloxacin, chloramphenicol and tetracycline isolated from western Kansas feedlots

Abstract In the United States thousands of tons of antibiotics are annually administered in low doses to livestock, both as prophylactics and growth promoters. Mounting evidence has shown that the overuse of antibiotics in livestock might render them, or their structural analogs, less effective when needed in veterinary as well as human medicine. To examine antibiotic resistance trends in feedlot soil, we collected soil samples from pens at ten beef cattle feedlots across western Kansas. Soil samples were screened for bacteria resistant to the human broad spectrum antibiotics ciprofloxacin, chloramphenicol, and tetracycline, by plating on them on Mueller-Hinton agar containing antibiotic concentrations of 100 μg mL−1. Resistant organisms were subcultured until axenic cultures were obtained. Bacteria were subsequently identified by submitting them to a commercial laboratory that utilizes 16S rRNA sequencing. We further assayed the organisms for resistance to more than one antibiotic. Some resistant isolate...

Effects of short-term exposure of feeder cattle to calves persistently infected with bovine viral diarrhea virus

Research using 2,954 auction-derived feeder steers and heifers was conducted at a single commercial feedlot in Kansas to determine the effects of testing for cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) at 10-14 days-on-feed (DOF), and removing them at 13-18 DOF. After removal of test-positive animals, the effect of the short-term exposure (STE) to PI cattle on health, performance and carcass characteristics was determined. The percentage of calves exhibiting signs of illness was increased (P<0.01) in cattle with STE to PI-BVDV. Cattle with no exposure (NE) to PI-BVDV calves had a morbidity rate of 18.8%, while a 29.6% morbidity rate was observed in pens of calves with STE to a PI-BVDV calf. Characterization of the temporal pen morbidity rate of STE and NE calves revealed that 31.7% of all STE and 15.3% of NE illness occurred in the first seven DOF. Additionally, the incidence of cattle treated for bovine respiratory disease in STE calves was 2.17 (95% CI 1.73 to 2.72) initial treatments per 1,000 head-days at risk, whereas the incidence of treatment of calves in NE pens was 1.28 (95% CI 0.98 to 1.68) initial treatments per 1,000 head-days at risk. Short-term exposure to PI-BVDV calves had no effect on retreatment rate, death loss, or performance. There was no evidence of a BVD-PI exposure X sex interaction (P=0.62) for carcasses that graded USDA Choice or better, but there was a main effect of sex (P<0.01). There was evidence of a BVD-PI exposure X sex interaction for Yield Grade 2 or greater carcasses (P=0.03). In this study, testing at 10-14 DOF was too late in the feeding period to eliminate the initial morbidity spike that occurred during 0-7 DOF, and the subsequent morbidity differences between calves with STE or NE to PI calves.

Cultural Energy Analysis of Pasturing Systems for Cattle Finishing Programs

ABSTRACT Data from a three-year study conducted to integrate pasturing systems with drylot feeding systems were used to assess cultural energy analysis of the cattle production systems. Each year, 84 fall-born and 28 spring-born calves of similar genotypes were brought from Oklahoma and used in the experiment. Fall-born and spring-born calves were started on test in May and October, respectively. Seven treatments were imposed: (1) fall-born calves directly into feedlot; (2) and (3) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of July; (4) and (5) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October; and (6) and (7) spring-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October. A 12.1 ha bromegrass pasture was available and divided into 16 paddocks of 0.69 ha each. Each treatment group had access to one paddock at a time and was rotated through one of four paddocks at approximately 3-day intervals. In the feedlot, steers were provided an 82% concentrate diet containing whole-shelled corn; ground alfalfa hay; and a protein, vitamin, and mineral supplement containing ionophore and molasses. When pens of cattle reached approximately 522 kg average live weight, they were processed into beef. Cultural energy used for pasture establishment and maintenance was calculated using the actual inputs and their corresponding energy values from literature. Cultural energy used for feedlot operations for Kansas feedlots obtained from literature was used. Cultural energy used for feed for treatments was derived from their corresponding lot feed consumption and their corresponding values from literature. Transportation energy was also included in the analysis. Since the objective of the study was to evaluate cultural energy analysis of the feeding systems, energy that the calves had deposited in their muscle and fat tissue when they were bought was deducted from carcass energy. Cattle going directly to feedlot had higher total cultural energy expenditures and those that spent longer time on pasture had lower than other treatments (P < 0.01). Feed energy constituted more than half of the total cultural energy and was highest for cattle going directly to feedlot and lowest for cattle spending the longest time on pasture (P < 0.01). Energy expended per kg live weight was highest for spring-born cattle (P < 0.01). The more time cattle spent on pasture, the lower was the energy output ratio defined as kcal input/kcal output (P < 0.01). Results show that pasturing for cattle is an effective way of reducing cultural energy expenditure and could be used to enhance the sustainability of agriculture and energy conservation.

Determination of Papillomatous Digital Dermatitis (PDD) Prevalence in the U.S. Feedlot Industry through Practitioner Survey

Papillomatous digital dermatitis has been recognized and studied within the dairy industry for nearly 30 years. Published literature describing the incidence, risk factors, treatment and probable etiology within dairies is readily available. Far less information is available concerning papillomatous digital dermatitis and its effects on the US feedlot industry. Although papillomatous digital dermatitis is rarely reported in feedlot cattle, there have been at least three confirmed cases in feedlots in Kansas and Iowa.

Pulsed-Field Gel Electrophoresis Patterns ofEscherichia coliO157 Isolates from Kansas Feedlots

This study investigated the prevalence and distribution of Escherichia coli O157 genetic types within and among feedlots using pulsed-field gel electrophoresis to separate XbaI-digested DNA. The study population consisted of 300 pens of cattle in 30 feedlots in Kansas that were sampled (feces, water, and water sediment) within a month of being shipped for slaughter. The prevalence of E. coli O157 was 8.5% in feces, 3.1% in water, and 4.5% in water sediment samples. A total of 424 E. coli O157 isolates were characterized by pulsed-field gel electrophoresis, and 139 subtypes (100% Dice similarity with no band differences) were identified. The majority of subtypes (70/139) was identified only once, but nine were identified 10 or more times. Identical subtypes were recovered from both feces and water tanks in 10 feedlots. The majority of subtypes were identified in only one feedlot, and the number of subtypes ranged from one to 23 within a feedlot and from one to seven within a pen. There were 10 feedlots with at least 15 positive samples. In these 10 feedlots, the most common subtype accounted for 16.9-78.6% of the isolates. Common subtypes differed among feedlots. In eight of the 10 feedlots, the most common subtype was identified in multiple pens. The results support a complex ecology for E. coli O157 in feedlot operations, with factors associated with exposure and transmission likely acting at a common level for multiple feedlots, within feedlots, and within pens of cattle.

Examining death loss in Kansas feedlots

This study had three primary objectives: 1) to determine if there is an annual and/or seasonal trend in percentage of death loss in Kansas feedlots; 2) to examine the difference in death loss between steers and heifers; and 3) to evaluate if "in" weight has had an effect on percentage of death loss in Kansas feedlots. The annual trend in death loss for both steers and heifers was found to be significant and positive, indicating that death loss has been increasing over the sample period. Seasonal increases in death loss were significant for early-spring closeouts for both steers and heifers. The annual trend in the difference between the death loss for steers and heifers, though not significant, was negative. There were, however, certain closeout months in which there were significant differences in the death loss of steers relative to heifers. Placement weight had a significant negative impact on death loss in heifer finishing, but no significant impact on steer finishing. Our regression analysis indicates that death loss has been increasing over the sample period, that certain closeout months tend to impact steer and heifer death loss differently, and that placement weight in heifers has had a significant impact on percentage of death loss in cattle.

Examining cost of gain in Kansas feedlots (2006)

This study had three primary objectives: 1) to examine the effects that individual performance and ingredient price factors have on cost of gain; 2) to quantify the annual and/or seasonal trend in cost of gain in Kansas feedlots; and 3) to examine the difference in cost of gain between steers and heifers. For both steers and heifers, corn price was significant and positive, indicating that as the price of corn increases so does cost of gain. The price of hay, which is a feedstuff in the majority of feedlot diets, has a positive, but insignificant, effect on feeding cost of gain. As average daily gain increased, predicted cost of gain decreased for both steers and heifers, but the result was only significant in steers. Death loss had a positive impact on cost of gain, but may be a more important factor when feeding steers. The trend over time was positive. Feed conversion is positive and highly significantly related to cost of gain for both steers and heifers. As feed conversion (feed/gain) increases, the cost of gain increases. There seems to be a significant negative trend over time in the difference between steer and heifer cost of gain, and the difference seems to be seasonal.

Effect of Risk Aversion on Feeder Cattle Prices

AbstractThis paper determines the effects of cattle feeders' risk aversion on feeder cattle prices using pen data of Kansas feedlots. Higher profit risk results in lower feeder cattle prices. The elasticity of feeder cattle price with respect to profit risk was small (-0.013). The risk elasticity estimated here is similar to risk elasticities in previous studies and thus, the use of pen-level data does not seem to add much to the study of risk.

Economic Feasibility of Using Composted Manure on Irrigated Grain Sorghum

The economic feasibility of using composted manure from western Kansas feedlots in combination with commercial N in the production of irrigated grain sorghum [Sorghum bicolor (L.) Moench] was evaluated. Effective disposal of large quantities of manure from large scale feedlots has been a concern. Yield data from a west central Kansas experiment station study was used to estimate a quadratic production function where grain sorghum yield is a function of compost and commercial N application rates. Four rates of commercial N (0, 55, 110, and 165 Ib/acre) and five rates of composted feedlot manure (0, 0.9, 1.8, 3.6, and 7.2 tons dry matter per acre) in a factorial arrangement were applied to irrigated grain sorghum [...]

Efficacy of using parasitic wasps to control stable flies in Kansas feedlots (1994)

Release of parasitic wasps has resulted in stable fly reductions averaging 28, 42 and 38% for 1991, 1992, and 1993, respectively, with considerable variation from feedlot to feedlot. Costs for parasites plus sampling averaged $.23, $.32 and $.26 per animal during 1991, 1992, and 1993, respectively. Because stable flies are estimated to cause losses of $5.00 to $30.00 per animal, these costs are very reasonable.

Management of stable flies in cattle feedlots with releases of parasitic wasps (1993)

During 1992, adult stable fly populations were sampled in 25 Kansas feedlots. A native stable fly parasitic wasp, Spalangia nigroaenea, was released in 19 of these feedlots. Stable fly populations were reduced up to 48% and parasite emergence was increased 21% when compared with feedlots where S. nigroaenea was not released. The percentage of total parasites that were S. nigroaenea nearly doubled in the release feedlots, compared to the nonrelease feedlots. This parasitic wasp has shown considerable promise for stable fly control in cattle feedlots. Overall, sampling and parasite costs averaged 32 cents per animal for the season.

Factors Affecting Carcass Characteristics and Palatability of Young Bulls

Young bulls (n = 202) of mixed breeding and unknown history were assembled at a commercial feedlot in Trial 1. At random, 101 of the young bulls were castrated. Steers and bulls were subjectively evaluated for frame size, muscle thickness, fat thickness, maturity and apparent breed-type. Bulls and steers (approximately 14 to 15 mo of age) were placed on a high-concentrate diet for 135 d, then transported to a commercial packing plant for slaughter and carcass evaluation. In Trial 2, young bulls (n = 589) that had been fed in commercial feedlots in Kansas, Oklahoma and Texas were assigned to apparent British, Brahman or Continental breed-types prior to slaughter. In Trial 1, beef from young bulls was less tender than beef from steers. Aging of steaks from young bulls for 13 d rather than 6 d significantly improved tenderness, as determined by Warner-Bratzler shear force and sensory panel evaluations. In Trial 1, level of marbling was more highly related to loin steak acceptability than fat thickness, sex or breed-type. In Trial 2, carcasses visually sex-classed as “bullock” had coarser lean texture, less marbling, less external fat thickness, heavier hot carcasses and numerically lower USDA yield grades than those classed as “steers.” Loin steaks from carcasses designated as “bullocks,” as opposed to those called “steers,” had higher (P < .05) shear force values after 6 d of postmortem aging but had equivalent shear force values after 13 d of aging. Loin steaks from the Continental-type bull carcasses from Trial 2 had higher (P < .05) shear force values at 6 and 13 d of postmortem aging than did loin steaks from carcasses of Brahman and British-type bulls.

Effect of Beef‐Feedlot‐Lagoon Water on Soil Chemical Properties and Growth and Composition of Corn Forage

AbstractLand disposal of beef‐feedlot‐lagoon (runoff) water was studied. Rates of 0, 8, 15, 26, and 46 cm/year of lagoon water were applied during the summers of 1970 and 1971 by furrow irrigation to a silty clay loam soil. Corn (Zea mays L.) forage yield and plant content of N, P, K, Ca, Mg, and Na were measured. Surface soil samples and soil cores were taken from the plots after harvest each year.Electrical conductivity ranged from 1.6 to 7.6 (3.1 average) mmho/cm in the lagoon water applied at the study site and from 1.0 to 12.8 mmho/cm in samples taken from 12 Kansas feedlots. Electrical conductivities of extracts from saturated pastes of the surface soil samples were increased linearly by accumulative treatment both years. The 1970 and 1971 soil cores showed accumulations of NO3−‐N, P, K, and Na in the top 30 cm at all treatment rates. Movement of NO3−‐N and Na down to 100 cm was noted in the 1971 cores from plots receiving 46 cm/year. Ca and Mg in the soil cores were not affected by treatment either year. Corn forage yields were a linear function of treatment in 1970 and a quadratic function in 1971. The positive effect on yield both years was attributed to increased soil fertility; the relative decrease in 1971 at the 26 and 46 cm/year rates was attributed to increased soil salinity. Maximum yield and uptake of N and P were reached at the 15 cm/year disposal rate in 1971.