Master of Science / Department of Animal Sciences and Industry / Dale A. Blasi / Low-frequency (LF) radio frequency identification (RFID) transponders (n = 1,993) representing both full-duplex and half duplex air interface technologies were evaluated. Transponders representing five manufacturers and seven types were evaluated for read distance (RD), resonance frequency (RF) and voltage response (VR). LF RFID transceivers (n = 24) were also evaluated for performance and variance as tested by read distance. Transponders were sorted into four categories based on RD performance on three transceivers, “Top 25%,” “Middle 50%,” “Bottom 25%,” and “No Read.” These categories were used for evaluation of transponders and transceivers in experiments one and two, respectively. In experiment one, the mean RF of the “Top 25%” transponders were closer to 134.2 kHz (P < 0.05) within a transponder type (TT). TT and mean RD performance category interacted to affect the VR of transponders (P < 0.05); transponders with lower VR tended to have longer RD within a TT. In experiment two, sixty transponders from the “Middle 50%” were used to evaluate transceivers. Transceivers represented five manufacturers and five transceivers per manufacturer; one transceiver was eliminated from testing due to mechanical problems. There was a significant interaction (P < 0.0001) for TT and transceiver manufacturer. This indicated that transceiver performance was greatly dependant on TT being interrogated. TT and transceiver manufacturer interacted to affect RD variance (P < 0.05) demonstrating that transceiver RD will vary depending on TT being interrogated. In the final study, electromagnetic interference (EMI) was evaluated in fourteen livestock auction markets, four feedlots and five cattle abattoirs. The presence of EMI is known to impair the performance of RFID equipment. However, this phenomenon in livestock management settings has not been quantified in the scientific literature. EMI (134.2 + 25 kHz) was observed in all abattoirs. However, the extent and duration of EMI varied depending on individual abattoir. The processing, load and unload areas were evaluated in commercial feedlots. The most EMI was observed in the processing area. Finally, EMI was observed at the sale ring exit at two livestock auction markets. EMI exists in livestock management settings and may negatively impact the performance of LF RFID.

Master of Science / Department of Animal Sciences and Industry / K C Olson / Prepartum fat supplementation has been associated with improved reproductive performance by cows managed for AI. Our objective was to evaluate the effects of prepartum supplementation with whole cottonseed or whole raw soybeans on response to ovulation synchronization and timed artificial insemination in mature beef cows. Cows (n = 188; average initial BW = 579 [plus or minus] 54 kg) were stratified by BCS and BW and assigned to 3 supplementation treatments: whole raw soybeans (21.6 % fat, 38.6% CP), whole fuzzy cottonseed (21.7% fat, 21.1% CP), or a 50:50 mixture of ground corn and soybean meal (2.6% fat, 30.6% CP). Supplements were fed at 1.8 kg per animal daily for 45 d before the first projected calving date (April 1). Supplementation was continued until each cow calved; thereafter, all cows received the control supplement until May 1. Ovulation was synchronized using the CoSynch + CIDR protocol and cows were bred via AI on June 21. Eleven d after AI, cows were exposed for natural service breeding for 50 d. Conception to AI was assessed 33 d after AI. Overall conception was assessed and conception to AI reaffirmed 126 d after AI. Body weight of cows fed control or oilseed supplements was similar (P > 0.3) at calving, initiation of ovulation synchronization, and at the end of the breeding season. Cottonseed-supplemented cows lost more BW and more BCS (P < 0.03) from the beginning of the trial to calving than those fed soybeans. Proportion of cycling cows was similar (P = 0.57) between treatments. Pregnancy to timed AI and final pregnancy rates were similar (P > 0.75) between control and oilseed-supplemented cows. Conversely, supplementation with cottonseed was associated with increased AI conception (P = 0.08; 54 and 39%, for cottonseed and soybeans, respectively) and greater final pregnancy rate compared to soybean-fed cows (P = 0.03; 100 and 93% for cottonseed and soybeans, respectively). Calf birth weights and calf weights at the end of the breeding season were similar (P > 0.24) between treatments. Effects of cottonseed and soybean supplementation on response to ovulation synchronization and timed AI by beef cows warrant further study.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Tiruvoor G. Nagaraja / Escherichia coli O157:H7 is a food-borne pathogen that causes hemorrhagic enteritis in humans. Cattle are asymptomatic carriers and their feces are the major source of infection. The objective of the first study was to determine the prevalence of E. coli O157:H7 in the gut of cattle at slaughter. Gut contents (rumen, cecum, colon and rectum) were collected from slaughtered cattle (n=815) at a packing plant and prevalence of E. coli O157:H7 was determined. The overall prevalence of E. coli O157:H7 in cattle was 20.6%. The prevalence (%) in the rumen, cecum, colon, and rectum was 4.9, 9.1, 7.7, and 10.3, respectively. Prevalence in rectal content was positively associated (P < 0.01) with that of the rumen or colon and not of the cecum. Pulsed-field gel electrophoresis typing showed that the majority of isolates obtained within the same animal shared a clonal similarity. There was no significant difference in the acid tolerance of ruminal compared to hindgut isolates. It was concluded that hindgut was the major site of prevalence of E. coli O157:H7 in cattle at slaughter. Neomycin, an aminoglycoside, is approved as a feed additive and for use in water to cattle. The objective of the second study was to determine the efficacy of feeding neomycin on fecal shedding of E. coli O157:H7 in cattle. Cattle were randomly assigned to control (n=14) or neomycin (n=10) supplemented group and orally inoculated with nalidixic acid-resistant (NalR) E. coli O157:H7. Neomycin was fed at 10 mg/0.45 Kg body weight for 15 days. Fecal samples and rectoanal mucosal swab (RAMS) samples were collected day before (d -1), on days 1, 3, 5, 10, 13, 17, 20, 24, 27, 31, 34, 38, 41, 44, and 48, and then approximately weekly through day 111. Fecal shedding of NalR E. coli O157:H7 was quantified and prevalence in RAMS was determined. Neomycin significantly reduced prevalence and concentration of E. coli O157:H7 compared to the control. Following two weeks of neomycin feeding, concentration and prevalence were similar between the two groups. Short term neomycin feeding before slaughter may reduce the E. coli O157:H7 load in cattle.

Master of Science / Department of Animal Sciences and Industry / Joe D. Hancock / Six experiments were completed to determine factors influencing the use of distillers dried grains with solubles (DDGS) in diets for nursery and finishing pigs. In Exp. 1, 105 nursery pigs were fed corn-soybean meal (SBM) based diets with CP concentrations of 22.5, 25, and 27.5%. Overall ADG, ADFI, and G:F were not affected by increasing CP (P > 0.19). In Exp. 2, 105 nursery pigs were fed excess CP from SBM and DDGS. Overall ADG, ADFI, and G:F for pigs fed the control diet were not different from those fed the high CP treatments (P > 0.12). However, pigs fed the DDGS treatment had lower G:F than pigs fed the corn-soy diet with similar CP content (P < 0.04). For Exp. 3, 176 finishing pigs were fed diets with CP concentrations increasing from 12 to 18%. Increasing CP had no effect (P > 0.20) on ADG, ADFI, G:F, and hot carcass weight (HCW). For Exp. 4, 180 finishing pigs were fed excess dietary CP from SBM and DDGS. Pigs fed diets with high CP had lower ADG, ADFI, and HCW, but these results were caused by the diet with 40% DDGS (SBM vs DDGS, P < 0.001). For Exp. 5, 224 nursery pigs were used to determine the effects of extrusion processing on the nutritional value of DDGS. Overall ADG and ADFI were greater for pigs fed the corn-soy control compared to the DDGS treatments (P < 0.02). Extruding the DDGS did not improve ADG or G:F (P > 0.11), but DM and GE digestibility were greater for diets with extruded DDGS vs. unprocessed DDGS (P < 0.04). In Exp. 6, 200 finishing pigs were fed DDGS-based diets formulated for ME, NE, and digestible amino acids. Feeding DDGS lowered ADG (P < 0.09) and ADFI (P < 0.05). Formulating for ME, NE, and digestible amino acids needs improved ADG and G:F (P < 0.002) to that of the corn-soy control diet. In conclusion, moderate excesses of dietary CP does not impact growth performance. Also, extruding DDGS can improve the nutritional value of diets for nursery pig and formulating for ME, NE and digestible amino acid needs can improve growth performance of finishing pigs fed diets with high levels of DDGS.

Doctor of Philosophy / Department of Animal Sciences and Industry / K C Olson / The objective of this series of studies was to examine select factors that affect behavior of beef cattle grazing native-tallgrass rangelands. Mineral supplements with divergent palatability characteristics were delivered to beef cows grazing native tallgrass range during various seasons of the year in order to measure mineral intake, frequency of supplement use, and duration of supplement use. We concluded that molasses-based mineral supplements influenced the activities of grazing cows more strongly than salt-based mineral supplements. These influences extended to the amount of supplement consumed as well as to the frequency, duration, and timing of use. Diet selection preferences of experienced, multiparous beef cows and naïve, primiparous beef cows grazing dormant, native tallgrass pastures were examined also during a short-term winter grazing bout. Naïve, primiparous cows selected more forbs and fewer grasses than experienced, multiparous cows. Previous research indicated that preference for broadleaf plants generally increased with grazing experience; however, these conclusions were based on research with greater-quality forages than those evaluated in our study. The differences in diet selection patterns between experienced, multiparous cows and naïve, primiparous cows during a short-term winter grazing period could be indicative of differences in long-term foraging strategies. In addition, the botanical composition of diets grazed by lactating beef cows with suckling calves and non-pregnant, non-lactating beef cows grazing either burned or unburned native tallgrass prairie during summer were evaluated. There were no differences in botanical diet composition between lactating cows suckling calves and non-lactating cows. In contrast, total graminoid selection was greater on burned (74.2%) than unburned pastures (71.8%) and total forb selection was greater on unburned (28.2%) than burned pastures (25.8%). We interpreted these data to suggest that forage selection preferences of beef cows can be altered with spring burning of native tallgrass pastures. Effects of large, round hay bale feeding method on intake of smooth bromegrass hay and eating behavior by beef cows were examined on dormant tallgrass prairie pastures during winter. Three large, round hay bale-feeding systems were evaluated: bales fed in a ring feeder, bales unrolled on the ground, and bales chopped with a flail-type hay processor (20-cm particle length) and deposited on the ground. Hay intake, hay refusal, frequency of use, and duration of use were not influenced by hay-feeding method. Foraging behaviors of beef cows in our studies were influenced by supplement type, cow age, and prescribed burning of rangeland. Conversely, foraging behaviors of beef cows were not influenced by lactation or by hay-feeding method.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Christopher D. Reinhardt / The effects of supplementing forms of flaxseed on plasma and longissimus muscle (LM) fatty acid (FA) composition, finishing performance, and carcass characteristics were evaluated in five studies. In study 1, steers were fed diets with soy oil (SO), ground flaxseed (Flaxseed), or urea formaldehyde condensation polymer treated flaxseed (UFCP). In study 2, steers were fed diets with SO, linseed oil (LO), or a combination of flaxseed and field peas that was extruded (LinPro). Feeding flaxseed products increased (P < 0.01) α-linolenic acid (ALA), omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to cattle fed SO. Feeding LinPro increased (P < 0.01) ALA, omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to steers fed SO or LO. In studies 3 and 4, steers were fed diets with and without Flaxseed and implanted or not. Implanting improved (P ≤ 0.05) DMI, ADG, feed efficiency, HCW, and LM area compared to cattle not implanted. In study 4, cattle fed Flaxseed had increased (P < 0.01) ALA and omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to cattle fed SO. In study 5, heifers were fed diets with 0% or 5% linseed meal, and administered with or without exogenous hormones (NHTC). Administering exogenous hormones improved (P ≤ 0.02) DMI, ADG, G:F, and HCW compared to NHTC cattle. Omega-3 FA increased in LM when cattle were supplemented with flaxseed products. Cattle fed LinPro achieved the highest levels of ALA and omega-3 FA. Flaxseed products did not interact with implants as a natural growth promoter in finishing cattle.

Master of Science / Department of Animal Sciences and Industry / KC Olson / Condensed tannins (CT) in plants are phenolic compounds with relatively high binding affinities for proteins. In ruminants, dietary CT limit DM intake and digestibility, and ruminal protein degradation by forming CT-protein complexes. Effects of dietary CT, animal species, prior dietary CT exposure, and antimicrobial inclusion on 48-h rate and extent of digestion were measured in two in vitro experiments. Cattle, sheep, and goats (n = 3 / species) were used in a 2-period, randomized complete-block experiment with a 2 × 3 × 2 × 3 factorial arrangement of treatments. Factor 1 was substrate: tannin-free or high-CT. Factor 2 was source of ruminal fluid inoculum: cattle, sheep, or goat. Factor 3 was prior animal exposure to a high-CT diet: non-exposed or exposed. Factor 4 was inclusion of antimicrobials: no antimicrobial, penicillin + streptomycin to suppress bacterial activity, or cycloheximide to suppress fungal activity in the fermentation. Tannin-free or high-CT substrates were incubated in vitro using ruminal fluid from animals either not exposed (period 1) or exposed to dietary CT (period 2). Periods consisted of an adaptation to tannin-free (10 d) or high-CT diets (21 d) and a 15-d period of ruminal-fluid collection via stomach tube. The presence of CT or penicillin + streptomycin in in vitro fermentation reduced (P < 0.001) total gas pressure, DM disappearance, and total VFA, acetate, propionate, butyrate, valerate, and branched-chain VFA concentrations. We concluded that: 1) CT had negative effects on fermentation, 2) prior exposure to dietary CT attenuated some but not all negative effects, and 3) CT effects were similar to the effects of penicillin + streptomycin.

Master of Agribusiness / Department of Agricultural Economics / Rodney D. Jones / After remaining stable for several decades, corn price has recently had unprecedented price increases and volatility. United States Department of Agriculture (USDA) predicts an average corn price of $5.80 per bushel for 2008, which is 232% of its 28-year (1980-2007) average price of $2.50. The record increase in corn price was the result of increased starch-based ethanol production associated with increased energy costs, and other factors such as a declining value in the United States dollar, and increased global commodity demand. High corn prices have impacted the profitability of the livestock feeding industry. It was less clear how the record high corn prices would affect the cow-calf industry since corn is not a significant input for cow-calf enterprises. This study quantified the relationship between cow-calf profitability and corn price. Because feed costs for a cow-calf producer are among the highest variable costs for the operation, both grazing and non-grazing feed costs were estimated as a function of corn price. Models were estimated to determine if a relationship between corn price and Returns Over Variable Costs (ROVC) at the cow-calf level could be identified. Corn price from 1978-2007 explained none of the variability in grass grazing rental rate, however when the projected 2008 corn price was included in the analysis, corn price explained 10% of the variation in grass grazing rates. Year (linear time trend) and corn price from 1978-2008 explained 88% of historical grass grazing rental rate variability, 71% of alfalfa price variability, and 63% of other hay price variability in Kansas. These results suggest that the new corn market paradigm likely will increase the relationship between corn price and feed costs at the cow-calf level. Several models were evaluated using bulk diesel fuel price, feeder calf price, corn price, alfalfa price, other hay price, and grass grazing rental rate to estimate Kansas cow-calf producer ROVC. Models that included diesel fuel price, feeder calf price, grazing rent, and one of the harvested feeds (corn, alfalfa, or other hay) price explained 90-91% of the variability in ROVC. Models that included diesel fuel price, feeder calf price, and either grazing rent or corn price explained less of the variability in ROVC; using grazing rent explained 89% and using corn price explained 79%. Including grass grazing rental rate along with corn price, feeder calf price, and bulk diesel fuel price improved the model's ability to predict ROVC, explaining 91% of the variability. While cow-calf producers might use very little corn directly in their operations, this research shows that corn price is an important determinant of cow-calf production returns, and corn price can be used by producers to plan for future rising costs in order to maximize returns.

Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / Two experiments were conducted to determine the effects of dried distillers grains with solubles (DDGS) on pork loin and fat quality. In the first experiment, 1,160 barrows (PIC) were used in a 70-d study to determine the influence of DDGS and glycerol on pork loin and fat quality attributes. Barrows were fed a corn-soybean meal based diet with the addition of selected levels of DDGS (0 or 20%) and glycerol (0, 2.5, or 5%) feed stuffs. Loins from the two heaviest pigs in each pen were removed for evaluation of pork loin and fat quality. Experiment two was a pilot study, in which eight non-pregnant sows were fed either 0 or 50% DDGS with a corn soybean meal based diet for 92-d. In the first experiment, there were no DDGS x glycerol interactions for purge loss %, instrumental color (L*a*b*), visual color, marbling score, drip loss %, visual color, pH, Warner-Bratzler shear force (WBSF), cook loss %, myofibrillar tenderness, juiciness, pork flavor intensity, connective tissue amount, and overall tenderness. There was a DDGS x glycerol interaction (P<0.03) for off-flavor intensity. Pigs fed diets with 20% DDGS had higher WBSF values, lower myofibrillar tenderness, lower overall tenderness scores, lower connective tissue scores, and had more off-flavors (P<0.05). Loin fatty acid analysis revealed an increase in palmitoleic, linoleic, and eicosadienoic acids (P<0.05) and iodine value (P<0.03) for pigs fed 20% DDGS. In the second experiment, there were no differences (P>0.64) in BW or backfat change for sows fed either 0 or 50% DDGS. No differences (P>0.23) in lipid oxidation from lean trimmings as measured by 2-thiobarbituric acid reactive substances (TBARS) assay were reported either initially or after 5 d of retail display for sows fed either 0 or 50% DDGS. As expected, lipid oxidation increased (P<0.003) as measured by TBARS assay for both treatments from d 1 to 5. Jowl fatty acid analysis revealed an increase in linoleic acid (P<0.01), total polyunsaturated fatty acids (P<0.01), and the ratio of polyunsaturated fatty acids to saturated fatty acids (P<0.03) for sows fed 50% DDGS.

Master of Science / Department of Agronomy / Clenton E. Owensby / Currently there are no model inputs for eastern gamagrass [Tripsacum dactyloides (L.) L] for use in the National Research Council's (NRC) beef cattle model. This study was conducted to determine model inputs for two eastern gamagrass varieties for use with the forage database of the NRC model. Cattle producers in the Midwestern US will be able to evaluate eastern gamagrass in a forage system and estimate net energy for maintenance (NEm), metabolizable protein (MP), and degradable intake protein (DIP) balance for various production scenarios. Eastern gamagrass varieties 'Iuka' and 'Pete' were arranged in a split-plot randomized complete block experiment with four replications. Varieties were whole plots with harvest maturities as split plots. Plant tissue was harvested from both varieties at four maturities: vegetative/early elongation, anthesis, seed shattering and dormancy. Various compositional attributes were determined on forage samples to enable the determination of model inputs for predicting energy and protein balances. A slight difference between varieties was found for crude protein concentration (p<0.05). Differences (p<0.05) due to maturity were found for all analyses used in the model, corroborating the decline in nutritive value of eastern gamagrass with advancing maturity. Neutral detergent fiber (NDF) ranged from 593 g kg-1 at the vegetative/early elongation stage of maturity to 731 g kg-1 at dormancy. Assumed animal and environmental inputs were used for beef cattle at two stages: nonlactating 160 d prepartum and 60 d peak lactation. Energy and protein balance were estimated using level I of the model. The vegetative/early elongation stage of development supplied the greatest amount of MP. Digestible intake protein declined as plant tissue matured. All but the vegetative/early elongation stage of maturity were limited in DIP for cows in both stages of production. Soybean meal was used as a protein supplement in amounts ranging from 0.8 kg to 1.4 kg to meet nutritional demands of cattle grazing eastern gamagrass at anthesis, seed shattering and dormancy. In the simulations conducted, eastern gamagrass would be an acceptable forage source for beef cattle provided that appropriate protein supplementation was given when the forage was at more advanced stages of maturity.