Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3717. Adviser: Jan Novakofski. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6121. Adviser: Peter James Garlick. Includes bibliographical references (leaves 72-89) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6119. Adviser: Robert G. Hoeft. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Doctor of Philosophy / Department of Animal Sciences and Industry / Evan C. Titgemeyer / Effects of energy supply on the efficiency of methionine and leucine utilization in growing steers were evaluated in 3 studies. We hypothesized that increased energy supply would improve efficiency of amino acid utilization. In study 1, treatments were abomasal infusion of 0 or 3 g/d of L-methionine and supplementation with 3 amounts of energy (0, 1.3, and 2.6 Mcal GE/d) in a factorial design. Nitrogen balance was increased (P<0.05) by methionine supplementation and increased linearly (P<0.05) with energy supply, indicating that efficiency of methionine use was improved by energy supplementation. In study 2, the effects of supplementation with no energy or isocaloric (1.3 Mcal GE/d) supplementation with glucose, fat, acetate, or propionate at 2 levels of L-methionine supplementation (0 or 3 g/d) were evaluated. Supplemental energy increased (P<0.01) nitrogen retention, without differences among energy sources. The results indicated that energy supplementation improved the efficiency of methionine utilization, independent of energy source. In study 3, effects of energy supplementation on leucine utilization in growing steers at 2 body weights (150 kg in Exp. 1 and 275 kg in Exp. 2) were evaluated. Treatments were a 3 × 2 factorial with 0, 4, or 8 g/d of L-leucine infused abomasally and 2 amounts of energy (0 and 1.9 Mcal GE/d). In Exp. 1, nitrogen retention linearly increased in response to leucine supplementation when additional energy was supplied. When no energy was supplemented, nitrogen retention was similar for 4 and 8 g/d of leucine. Energy supplementation increased nitrogen retention (P<0.01), indicating that energy supplementation improved the efficiency of leucine utilization by modestly increasing nitrogen retention when leucine was limiting and by increasing the ability of steers to respond to the highest amount of supplemental leucine. In Exp. 2, nitrogen retention was not affected by leucine supplementation, indicating that leucine did not limit protein deposition. Energy supply increased nitrogen retention (P<0.01) independent of the level of leucine supplemented, demonstrating an increase in capacity for protein deposition when energy was supplemented. Overall, our results indicated that energy affects the efficiency of amino acid utilization, challenging the assumption of a constant efficiency of use.

Doctor of Philosophy / Department of Animal Sciences and Industry / Jim L. Nelssen / The overall objective of these experiments was to develop management and feeding programs to increase sow longevity and productivity by improving welfare conditions. In Exp. 1, 208 gestating sows and 288 gestating gilts were utilized to determine the effect of feeding frequency (2 vs. 6) on performance and welfare issues. Feeding frequency had no affect on growth and reproductive performance in gestating sows; however, increasing the feeding frequency did improve the welfare measurements in this trial. Gilts fed six times a day did have increase ADG during d 0 to 42; however, there was no affect on performance from d 42 to farrowing. In Exp. 2 (630 pigs in 4 studies), increasing the feeding frequency (2 vs. 6) of a restricted feeding level increased growth performance of finishing pigs. This affect is likely due to the increase of available energy above maintenance when compared with the gestating sows. In Exp. 3, different feed drops used for delivering feed were evaluated. The Accu and the Ultra feed drops were more accurate than the Econo feed drop at angles of 90, 75, and 60°. The difference in accuracy is potentially related to the way that the drops attach to the feed line. However, the amount of feed that is collected in each drop appears to increase linearly as the feeder settings are increased. Thus, regression equations for the angle of the feed drop can be developed to adjust for the variability in the amount of accumulated feed. In Exp. 4, Alimet® was used to determine the TID TSAA:Lys ratio for ADG and G:F of 63 and 66% for Genetiporc and 61 and 56% for PIC pigs weighing between 10 to 20 kg. In Exp. 5, the optimal TID Lys:Calorie ratio was estimated to be 3.7 and 4.1 g Lys/Mcal ME for the Genetiporc and PIC pigs weighing between 10 to 20 kg . The ratios were than validated at two energy levels and the amount of TID Lys that was used for lean gain was similar for both genetic lines at approximately 20 g of Lys for each kg of gain.

Master of Science / Department of Clinical Sciences / Michael Sanderson / Biosecurity, biocontainment and security practices are important in production animal agriculture. Procuring cattle from multiple sources and commingling them into a single confinement operation increases risk of disease introduction. The large concentration of animals makes a feedyard a more likely target of a domestic or international terror group. Controlling or eradicating an intentionally introduced pathogen or toxin would be costly. The aim of these surveys was to gather information from experts about perceived risks and mitigation strategies and to assess current practices of biosecurity, biocontainment and security in Central Plains feedyards. Consulting veterinarians and feedyard managers shared similar views on the likelihood of disease caused by terrorism, natural introduction or accidental introduction, and on the importance of on-site security. They disagreed on the importance of preventative products, disease transmission control, and environmental control. Generally speaking, feedyard managers believed environmental control to be more important than consulting veterinarians. In reference to a survey of current practices, some feedyards use equipment for both manure and feed handling. Many feedyards are not cleaning and disinfecting oral treatment equipment, treatment facilities, or unloading facilities on a regular basis which may increases their risk for indirect disease transmission of endemic agents such as Salmonella or BVDV. Most feedyards in this survey import some cattle directly from an auction market, do not require clean boots or foot covering to be worn by visitors, and do not require trailers to be cleaned. Smaller feedyards were more likely to require trailers to be cleaned before loading incoming cattle. Less than half of the feedyards reported having a fence that will stop humans or kept protein supplements or micro-nutrients secured from access. Some feedyards enforced a visitor log or employed a night watchman. Most feedyards learned about a future employee by calling references listed in resume, but some performed a criminal background check. A cost-benefit analysis should be done on all management practices to determine economic benefits. More research is needed to better understand which practices are most beneficial.

Doctor of Philosophy / Department of Animal Sciences and Industry / Michael E. Dikeman / Two experiments were conducted to evaluate the effects of dietary vitamin A on growth, carcass characteristics, and meat quality of ruminants. In Experiment 1, 40 crossbred wethers (BW = 28.7 kg) were assigned to 1 of 4 treatments: backgrounding (BG) and finishing (FN) with no vitamin A (LL); BG with no vitamin A, FN with high vitamin A (6,600 IU[dot in middle of line]kg [superscript-1] diet) (LH); BG with high vitamin A and FN with no vitamin A (HL); and BG and FN with high vitamin A (HH). During BG (d 1 to 56), intake was restricted to achieve 0.22 kg ADG. During FN (d 57 to 112), lambs consumed the same diet ad libitum. Lambs were humanely slaughtered after 112 d. There were no treatment differences (P > 0.05) in feed intake, ADG, or final BW. Carcasses from the HH group had higher (P < .05) marbling scores (514 vs. 459), and 25.8 % more extractable intramuscular lipid (IMF) than LL (3.88 vs. 3.08 % for HH and LL, respectively, P < .05); the LH and HL treatments were intermediate. The was a negative correlation (r = -0.38) between serum fatty acid content and %IMF. Experiment 1 data suggest that increased marbling may be achieved with high vitamin A for 112 d in lambs. In Experiment 2, Angus crossbred steers (n = 48), were either early-weaned (EW) at 137[plus or minus]26 d of age or weaned at a traditional age (TW) 199[plus or minus]26 d and allotted to either 42,180 IU vitamin A[dot in middle of line]hd[superscript-1][dot in middle of line]d[superscript-1] (HA) or no vitamin A (NA). Early- and TW steers consumed treatments for 235[plus or minus]17 and 175[plus or minus]18 d, respectively. Serum and liver retinol content diverged dramatically (both, P < 0.01) by the end of the experiment and TW steers tended (P > 0.10) to have higher ADG than EW steers (1.31[plus or minus]0.2 and 1.48[plus or minus]0.2 kg[dot in middle of line]hd[superscript-1][dot in middle of line]d[superscript-1], respectively). Steers were humanely slaughtered at 1.02 cm fat. Weights tended (P = 0.08) to be heavier and carcasses were fatter (P < 0.05) for HA than NA. Marbling score and % IMF were higher (P < 0.05) for EW-NA than other treatments. Percentage of USDA Choice and Prime carcasses doubled (P < 0.05) for NA than HA. Yield grades increased (P < 0.05) with EW-HA and were similar (P > 0.10) among other treatments. Feeding NA was effective for increasing marbling without increasing fat; EW enhanced these effects. Reasons for the contradictory results in these 2 experiments are unclear. Species differences in the ability to metabolize retinol are implicated.

Master of Science / Department of Animal Sciences and Industry / Dale A. Blasi / The proposed U.S. National Animal Identification System (US-NAIS) has generated many concerns among beef cattle producers. The goal of the NAIS is to utilize 48-hour traceback in the event of an animal disease outbreak. The traceback would identify all animals that have had contact with the diseased animal, while linking an animal to its premises of origin. According to the Diffusion of Innovation theory, getting a new idea adopted, even when it has clear advantages, is often very difficult. However, by adopting innovations relatively sooner than others in their system, the theory demonstrates marked benefits for innovators and early adopters, as well as a widening of the socioeconomic gap. In this study beef producer demonstrated understanding, acceptance and adaptability to implement the US-NAIS. Participants for the study were selected in the spring of 2006 from a mailing list of cow-calf producers with more than 100 head of cows. BEEF Magazine provided the mailing list and a random sample of 1,000 producers was selected. The results show a knowledge gap between the proposed system and producer understanding. Producers were also divided on support for the proposed system. When ranking their level of support on a scale of 1 to 6, with 1 being strongly supportive and 6 being strongly opposed, 49% of producers showed some level of support and 48% showed some level of opposition, with a mean of 3.53 (s.d. 1.67). Data also highlights a lack of understanding of the regulations and implementation procedures among producers. The results of this study brought considerable insight into the current practices and perceptions of beef cattle producers, and will be used to develop educational materials to improve their understanding of this proposed program.

Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / A study was performed to determine the minimum effective dose of human chorionic gonadotropin (hCG) needed to induce ovulation of follicles in cattle (Exp. 1). Another study determined the effects of replacing the first injection of GnRH (d -7) with hCG or saline in a Resynch-Ovsynch protocol [injection of GnRH 7 d before and 48 h after PGF[subscript2alpha] before a resynchronized fixed-timed AI (TAI)] on pregnancy rates in cows diagnosed not pregnant and pregnancy survival in cows diagnosed pregnant (d 0; Exp. 2). A final study determined the ovulation potential of hCG compared with GnRH and saline (Exp. 3). In Exp. 1, ovaries of Holstein cows were mapped by using transrectal ultrasonography 7 d before pregnancy diagnosis. Cows were assigned to treatments of saline, 100 [Mu]g of GnRH, or 500, 1,000, 2,000, or 3,000 IU of hCG. Ovarian structures were monitored 7 d later and proportion of cows and follicles that ovulated were recorded. In Exp. 2, cows in 4 herds were assigned to treatments of 1,000 IU of hCG, 100 [Mu]g of GnRH, or left as untreated controls 7 d before pregnancy diagnosis. Nonpregnant cows were given PGF[subscript2alpha] (d 0), then inseminated 72 h later, concurrent with a GnRH injection. Pregnancy rates tended (P = 0.08) to be increased by GnRH (17.9%; n = 703) compared with control (12.9%; n = 505), but not hCG (16.5%; n = 541). Incidences of ovulation in nonpregnant cows (Exp. 3) were: hCG (51.6%; n = 126), GnRH (46.1%; n = 102), and control (28.1%; n = 96), whereas those in pregnant cows were: hCG (59.3%; n = 59), GnRH (24.5%; n = 49), and control (6.9%; n = 58). We concluded that: 1) a minimum dose of 1,000 IU of hCG resulted in a greater ovulatory response than saline, GnRH, or 500 IU of hCG (Exp. 1); 2) initiating a Resynch-Ovsynch protocol 7 d before pregnancy diagnosis with saline reduced timed AI pregnancy rates (Exp. 2); and 3) incidence of new CL was greater after hCG than GnRH in pregnant cows, but not in nonpregnant cows (Exp. 3).

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Escherichia coli O157, a food-borne human pathogen, causes hemorrhagic colitis and hemolytic uremic syndrome. Cattle are a major reservoir and the organism resides in the hindgut and is shed in the feces. Cattle feces are a major source of food and water contamination. Houseflies feed on cattle manure and are a source of E. coli O157 transmission. We have observed that houseflies have an affinity for a steam-flaked corn product (SFC-36) made from tempered whole corn that is more ruminally digestible than the traditional SFC (SFC-18). Therefore, we investigated whether SFC-36 diets contained and resulted in higher E. coli concentrations in the feces of cattle compared to SFC-18 diets. Concentrations of E. coli were not different between the two SFC diet samples, but resulted in higher coliforms in diets containing the SFC-36 after exposure to the environment. However, E. coli concentrations in feces from cattle fed the two diets were similar. In fact, cattle fed the diet containing SFC-18 flakes actually shed higher concentrations of coliforms. This led us to speculate that starch digestion may have an effect on the growth of E. coli O157 in the hindgut. We determined whether fecal E. coli O157 was related to fecal starch concentration. Steers (n=263) were sampled for E. coli O157 and fecal starch concentration determinations. Steers positive for E. coli O157 contained 21% more (P < 0.05) fecal starch than steers that were negative for E. coli O157. We attempted to alter the concentration of starch escaping rumen fermentation by feeding diets based on SFC and dry-rolled corn (DRC) to 30 heifers prescreened for being culture positive for fecal E. coli O157. Heifers were sampled for feces and by rectoanal mucosal swab (RAMS) weekly to monitor fecal pH and fecal starch concentration, and prevalence of E. coli O157. Based on RAMS, prevalence of E. coli O157 tended to be higher (P = 0.08) for heifers fed SFC than DRC diet. Fecal starch and pH were similar (P > 0.05) between positive- or negative-E. coli O157 heifers. Apparently, fecal E. coli O157 was not related to fecal pH or starch concentration in cattle.