<p>The goal of the Mississippi State University Extension Service (MSU-ES) is to improve the quality of life for all Mississippians. One specific group that agricultural change agents work with at the county level is beef producers. Grazing lands have received much attention over the last few years regarding environmental concerns and Best Management Practices (BMPs) for beef cattle operations. </p><p> The adoption of these practices was voluntary during the time this study was conducted, however; adoption was highly encouraged by the MSU-ES and the Natural Resources Conservation Service (NRCS). By knowing the level of adoption of BMPs that Mississippi beef producers have implemented, change agents can more effectively plan educational programming efforts for producers to better understand the importance of BMP adoption. </p><p> The purpose of this study was to describe the adopter categories of Mississippi beef producers as determined by Rogers (2003) adopter characteristics generalizations based on their (1) socioeconomic status, (2) personality values and communication behavior, and (3) opinions. It also examined the correlations between the adopter categories to predict the level of the three BMPs being studied. </p><p> The adopter categories were innovator, early adopter, early majority, late majority, and laggard. The three BMPs that were the focus of the study were rotation grazing, riparian buffers, and pasture renovation. </p><p> The results of the study indicated that Mississippi beef producers could be correctly identified in the adopter categories. By identifying the adopter categories of the Mississippi beef producers and then examining the correlations among the variables, prediction of BMP adoption of rotational grazing and riparian buffers was possible. </p><p> The relationships between MSU-ES agents and their programming efforts, as well as the relationships between NRCS district conservationist and their programs, were studied. Non-adoption, though not an adopter category, was also examined and the reasons for it were cited. </p>

Thesis (Ph.D.)--Cornell University, 2006. / (UMI)AAI3237606. Adviser: Hussni Mohammed. Source: Dissertation Abstracts International, Volume: 67-10, Section: B, page: 5478.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7036. Adviser: Floyd K. McKeith. 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: 67-07, Section: B, page: 3712. Advisers: Sharon M. Donovan; Kelly A. Tappenden. Includes bibliographical references (leaves 145-168). Available on microfilm from Pro Quest Information and Learning.

Doctor of Philosophy / Department of Animal Sciences and Industry / Twig T. Marston / The primary study investigated the use of ractopamine HCl and implants in cull beef cows. Thirty-two cull cows were used to determine the effects of feeding ractopamine HCl and/or implanting on feedlot performance and carcass composition. Cows were individually fed a high concentrate diet for 60 days. Carcass data were collected and carcasses were fabricated. Implanted cows had greater dressing percentages and tended to have heavier hot carcass weights than non-implanted cows. Cows that had been treated with implant and ractopamine HCl tended to be fatter than those not treated. Ractopamine HCl fed cows had more marbling than their contemporaries. The data also indicated that younger cows (< 6 years of age) had greater feedlot performance than the older cows. An experiment was conducted to determine if corn and grain sorghum dried distillers grains could be effective protein supplements for growing cattle. Crossbred heifers (n = 78) were individually fed 2.72 kg·head·-1d·-1 of supplements containing corn, soybean meal, and grain sorghum; or cracked corn and corn distillers grains with solubles; or cracked corn, sorghum distillers grains with solubles, and ground grain sorghum (all formulated to equal 20% CP). Heifers grazed native-grass and were fed smooth broom hay. A digestion trial was done during the last week of the trial. No differences were noted in weight gain or total diet digestibility, however, DMI was less for heifers receiving either distiller’s based supplement. Ninety-six pregnant, mature, spring-calving cows grazing native grass pasture were used to determine if early weaning calves reduced subsequent winter supplementation cost. Previous to the feeding trial, calves had been weaned at 115 or 212 d of age. Cows were fed either 1.4 kg·hd-1·d-1 or 1.27 kg·hd-1·d-1 of a common 45% CP supplement. Cows were supplemented for an average of 110 d of pregnancy. Earlyweaned cows were heavier and had greater body condition scores than contemporaries at the commencement of supplementation. At calving the early-weaned cows fed the lesser supplemental amount had similar body weight and body condition scores as later-weaned cows fed the greater amount of supplement, thus, the early weaning routine allowed a 30% savings of winter protein supplement.

Doctor of Philosophy / Department of Grain Science and Industry / Keith C. Behnke / A series of experiments were conducted evaluating the effects of marker selection and mix time on feed uniformity, feed uniformity on animal performance, and the addition of cracked corn to a concentrate pellet on broiler performance. Utilizing a common corn-soybean meal based poultry diet, as mix time increased, there was an overall decrease in % Coefficient of Variation (CV) observed, which was independent of which marker was used. Crude protein should be considered to be an inferior marker as several ingredients in the batch contribute some level of protein and overall decreased numerically less than 1% CV. Synthetic amino acids (methionine and lysine) prevailed as the most consistent markers reducing in magnitude by 60.32% and 55.97% (methionine and lysine, respectively). To evaluate the effects of feed uniformity on broiler performance, as determined by CV, methionine was added to a basal diet and mixed for 10, 20, 30, 40, or 120-s, with methionine being the only ingredient varying. During the starter period (d 0 to 16) ADG increased significantly (quadratic P<0.001) as well as F:G (quadratic P<0.001). However, in overall (d 0 to 41) growth performance only ADG improved (quadratic P<.001). Average daily feed intake appeared to be a contributing factor in growth performance for all stages of growth. Cracked corn was added to a concentrated pellet to evaluate growth performance on broilers and potential cost reductions at the feed manufacturing facility. A linear decrease was observed overall (0 to 41 d) for ADG, ADFI, and F:G (P<0.003, respectively). Gizzard weight and gizzard yield were significantly increased (P<0.043 and P<0.008, respectively) as cracked corn level increased.

Doctor of Philosophy / Department of Animal Sciences and Industry / Robert D. Goodband / Two experiments evaluated effects of glycerol on pellet mill production and pig performance. In Exp. 1, increasing glycerol increased (quadratic; P < 0.01) pellet durability index through 9% added glycerol. Adding glycerol decreased (linear; P > 0.01) production energy (kWh/t). In Exp. 2, pigs were fed one of seven diets with no added soy oil or glycerol (control); the control diet with 3 or 6% added soy oil, 3 or 6% added glycerol, and 6 or 12% additions of a 50:50 soy oil/glycerol blend in a 26-d growth assay. Adding glycerol improved (P < 0.01) pellet durability compared to soy oil and the soy oil/glycerol blend treatments. Pigs fed glycerol had increased (linear, P < 0.03) ADG. Adding soy oil, glycerol, or the soy oil/glycerol blend resulted in similar final BW. Two experiments evaluated the effects of glycerol as a replacement for lactose on pellet mill production and nursery pig performance. In Exp. 1, pigs were fed one of ten treatments that included 0, 3.6, or 7.2% lactose or 0, 3.6, or 7.2 % glycerol and fed in either meal or pelleted form. Pellet durability index increased (linear; P < 0.01) with added lactose and glycerol. Glycerol decreased (linear; P < 0.01) production energy (kWh/t). There was a tendency (P < 0.06) for an inclusion level × diet form (meal or pellet) interaction observed for ADG. Pigs fed the pelleted diets containing the 7.2% glycerol inclusion had decreased ADG compared to all other treatments. In Exp. 2, pigs were fed one of fourteen diets that included 0, 3.6, 7.2, or 10.8% lactose or 0, 3.6, 7.2, or 10.8 % glycerol and fed in either meal or pelleted form. There was no effect (P < 0.27) of diet form, inclusion level, or source on ADG or ADFI. Eight experiments evaluated the effect of ingredients on the flow ability of ground corn. Flow ability of feed improved with added glycerol, especially when added to meal diets containing hammer mill ground corn. Specialty protein ingredients in powder form reduce flow ability, while fine lactose sources improved flow ability. Granulated ingredients improved flow ability.

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / A series of five trials were conducted to evaluate grain processing, distiller's grains inclusion in finishing diets, interactions between distiller's grains and dry-rolled corn (DRC) or steam-flaked corn (SFC), efficacy of removing roughage in the presence of distiller's grains and the digestibility of distiller's grains in steam-flaked and dry-rolled corn diets. The first trial was designed to determine the optimum flake density of SFC in beef finishing diets. Diets consisted of corn flaked to densities of 360, 411, or 462 g/L. Observed improvements in mill production would support increasing flake density; however numerical decreases in animal performance offset economic benefits of increased productivity. The second trial was conducted to evaluate optimum levels of sorghum wet distiller's grains in finishing diets. Crossbred yearling steers were fed diets containing DRC or SFC and levels of distiller's grains were 0, 10, 20, or 30% of diet dry matter. Distiller's grains can effectively replaced a portion of the corn in finishing diets, but their nutritional value was greater in DRC diets than in SFC diets. In trial 3, crossbred heifers were fed diets containing SFC with 0% DDG and 15% corn silage (CS), 25% DDG and 15% CS, or 25% DDG and 5% CS. In trial 4, crossbreed heifers were fed diets similar containing DRC or SFC with 0% DDG and 15% CS, 25% DDG and 15% CS, or 25% DDG and 5% CS. Results indicate that roughage levels can be reduced in feedlot diets containing DDG with no adverse effects on performance or carcass quality. The fifth trial was a metabolism study conducted to evaluate the digestibility of DDG in beef cattle. Treatments consisted of DRC with 0% DDG, DRC with 25% DDG, SFC with 0% DDG, and SFC with 25% DDG. There were no significant grain processing by distiller's grain interactions observed in main effects. In conclusion optimum flake density was 360 g/L, feeding distiller's grains has a greater value in DRC diets vs. SFC diets, roughage level and type are important in formulating finishing diets, roughage can be reduced when feeding distiller's grains, and ruminal ammonia, and pH are decreased and ruminal lactate is increased when feeding DDG and SFC.

Doctor of Philosophy / Department of Animal Sciences and Industry / Jim L. Nelssen / Four experiments using 350 pigs were conducted to determine the effects of dietary nutrients on the incidence of osteochondrosis (OC) and to evaluate the use of biomarkers to predict its occurrence in growing-finishing pigs. The first experiment was conducted to evaluate the potential of dietary ingredients with known functions in cartilage and bone metabolism on incidence of OC in pigs (PIC 327 × 1050, initially 39 kg). Results suggest that pigs fed high levels of added copper and manganese, silicon, methionine and threonine, or proline and glycine had reduced OC severity scores. A second experiment evaluated other dietary ingredients that may impact OC as well as with or without ractopamine HCl (PIC 327 × 1050, initially 47 kg). Results suggest that feeding a combination of added methionine, manganese, proline, and glycine or added silicon can numerically reduce OC severity scores compared to pigs fed a standard corn-soybean meal based diet. Feeding ractopamine HCl did not affect the incidence or severity of OC. A third experiment was conducted to evaluate the effect of dietary lysine concentration with or without the addition of high methionine, manganese, and copper in a 3 × 2 factorial arrangement in growing-finishing pigs (PIC 327 × 1050, initially 41 kg). Results suggest that increasing dietary lysine concentrations increased the severity of OC. Furthermore, feeding additional methionine, manganese, and copper reduced OC severity scores. A fourth experiment was conducted to determine the usefulness of ten different biomarkers of cartilage and bone metabolism to predict the incidence of OC and the correlation of individual markers with the severity of OC. Results suggest that measuring serum C-propeptide of type II collagen (CPII) will predict animals with OC, as gilts with a two-fold increase in CPII are 97 times more likely to have OC. As well, serum collagen type II carboxy-terminal 3/4 long fragment (C2C) explained 49% of the variation in OC severity scores. The results of these experiments suggest that feeding added copper, manganese, methionine, silicon, or proline and glycine may reduce OC severity scores in pigs, while measuring biomarkers CPII and C2C can aid in determining animals with OC.

Master of Science / Department of Animal Sciences and Industry / Jim L. Nelssen / Five-hundred and four barrows and gilts were used in four experiments to determine the influence of dietary ingredients on fat quality. Experiment 1 evaluated feeding duration of choice white grease (CWG) and soybean oil. Increasing feeding duration of pigs fed CWG or soybean oil increased (quadratic, P < 0.01) iodine value (IV) in jowl fat and backfat. Pigs fed soybean oil had increased (P < 0.01) IV in jowl and backfat compared with pigs fed CWG. In Exp. 2 dried distillers grains with solubles (DDGS), extruded expelled soybean meal (EESM), and CWG were used to evaluate diets with common iodine value product (IVP) from ingredients varying in unsaturated fat level and concentration. Pigs fed either diet with DDGS had increased (P = 0.02) backfat and jowl fat IV, compared with all other treatments. Pigs fed EESM had increased (P = 0.04) backfat and jowl fat IV compared with the control, low CWG, and high CWG. Pigs fed low CWG and high CWG had increased (P = 0.04) jowl fat IV compared to the control. Increasing dietary fat increased carcass fat IV, with unsaturated fats from DDGS and EESM having a greater affect than more saturated fats, such as CWG, even when formulated to the same IVP. Experiment 3 evaluated the effects of increasing CWG in corn- and sorghum-based diets on fat quality. There was a grain source X fat level interaction (P = 0.04) for IV in both backfat and jowl fat. Adding CWG increased IV in backfat and jowl fat for pigs fed corn- and sorghum-based diets; however, the greatest increase was between 0 and 2.5% CWG in sorghum-based diets and between 2.5 and 5% CWG in corn-based diets. Despite this interaction, pigs fed corn-based diets had increased (P < 0.01) backfat and jowl fat IV compared with pigs fed sorghum-based diets. Increasing CWG increased (linear, P < 0.01) IV in backfat and jowl fat. Experiment 4 examined the effects of DDGS on fat quality. Backfat, jowl fat, and belly fat IV increased (linear, P = 0.02) with increasing DDGS in both the pigs marketed on d 57 and 78.