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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of Feeding Different Protein and Energy Supplements on Performance and Health of Beef Calves During the Backgrounding Period

Austin, Robert Jesse 15 August 2001 (has links)
Newly received or weaned calves are highly susceptible to the incidence of bovine respiratory disease. In addition to high levels of stress, decreased feed intake and exposure to foreign antigens result in increased morbidity and possibly death losses. Four backgrounding trials were conducted to examine the effects of protein and energy supplements to stressed calves consuming different forages. Body weights, rectal temperatures and blood samples were taken on d 0, 7, 14, 28 and 42. Supplements consisted of corn or mixtures of corn and soybean meal. In trial 1, 48 heifers (average BW = 219 kg) fed fescue hay in drylot, were allotted to four treatments: no supplement, 15% CP supplement (0.5% BW), 15% CP supplement (1.0% BW) and 30% CP supplement (0.5% BW). Supplemented heifers had higher (P<0.05) ADG than unsupplemented heifers by 42 d. Heifers fed the 30% CP supplement had higher (P<0.05) plasma urea-N by d 42. In trial 2 (pasture study 1), 36 steers (average BW = 217 kg) grazed stockpiled tall fescue and were allotted to three treatments: no supplement, a 15% CP supplement (0.5% BW), and a 15% CP supplement (1.0% BW). After wk 1, ADG was lower (P<0.05) for supplemented calves. At the end of the trial, steers supplemented at 0.5% BW had higher (P<0.05) ADG than steers supplemented at 1.0% BW. Glutathione peroxidase levels were lower (P<0.05) for supplemented steers on d 28. For trial 3 (pasture study 2), 48 steers (average BW = 202 kg) grazed stockpiled tall fescue and were allotted to three treatments: no supplement, corn (1% BW), and 15% CP supplement (1% BW). After wk 1, ADG was higher (P<0.05) for steers supplemented with corn. Steers supplemented with 15% CP supplement had the lowest (P<0.05) ADG after 7 d. At d 42, supplemented steers gained faster (P<0.05) than unsupplemented steers. For trial 4 (pasture study 3), 48 steers (average BW = 202 kg) grazed stockpiled tall fescue or fescue-alfalfa and were allotted to two treatments: no supplement and a 15% CP supplement (0.5% BW). During wk 1, steers grazing fescue had higher (P<0.05) ADG than steers grazing fescue-alfalfa. During wk 1, supplemented steers had a higher (P<0.05) morbidity scores. At d 42, ADG was higher (P<0.05) for supplemented steers. No consistent differences were detected in forage and blood serum mineral concentrations in all trials. Glutathione peroxidase activity increased (P<0.05) for all trials on d 14, regardless of supplementation. Supplementation improved ADG by d 42 but did not affect overall health status of calves in all trials. / Master of Science
2

Effect of backgrounding systems on winter and finishing performance, forage intake, carcass characteristics of beef calves and economic analysis

Kumar, Ravinder 31 March 2011
A 2-year winter grazing and feedlot finishing trial (Exp 1) and subsequent in-situ nutrient disappearance study (Exp 2) were conducted to evaluate the effects of swath grazing forage barley (Hordeum vulgare, cv. Ranger) or foxtail millet (Setaria italica, cv. Golden German) compared to grass-legume hay fed in drylot on calf performance. In trial1 in each of 2 years, 120 spring born Angus calves (60 steers, 60 heifers) were fall weaned, stratified by weight, allocated into 20-head groups then assigned randomly to one of the three replicated (n=2) backgrounding (BG) systems. Backgrounding systems were (i) swath graze barley (BR); (ii) swath graze millet (ML); and (iii) bunk fed ground hay drylot (DL). Swath grazed calves were limit fed in 8 ha paddocks with 3 d grazing periods, using electric fencing for 96 d each year. All groups received a pelleted supplement at 0.62% BW. Calves were weighed at start, every 21 d and end of background period. Following the BG period, calves were placed in feedlot, separated by sex and BG treatment and fed a similar finishing ration and harvested at a targeted endpoint of 12 mm back fat. Forage samples collected every 21 d were analyzed for DM, CP and digestible energy (DE) and change in nutritive quality over the grazing period. DE content was greatest (P<0.05) for BR (2.6 Mcal/kg) and least for DL hay (2.2 Mcal/kg). Quality of all the three forages did not change over the grazing period except for an increase (P<0.05) in NDF of millet. Calf ADG was greatest (P <0.05) for BR compared to ML or DL, while dry matter intake (DMI) of the BR calves tended to be greater (P=0.11) than ML or DL calves. No treatment differences were observed in the finishing ADG (P>0.05) and carcass characteristics (P>0.05) of calves from the three backgrounding systems. In Exp 2, four dry ruminally cannulated Holstein cows fed ground grass hay were used in an in-situ degradability study to determine the extent of degradation and rumen kinetic parameters of the 3 forages used in Exp 1. Effective degradability of DM and CP iii were similar for barley and millet and greater (P<0.05) than grass legume hay while NDF degradability (P<0.05) of millet was greater than that of barley or grass legume hay. These findings indicate that swath grazing barley or foxtail millet fed to beef calves resulted in similar or decrease performance compared to a traditional drylot pen system. Cost of gain for the barley swath grazed backgrounding system calves was 43 and 60.5% lower compared to a swath grazed millet or drylot system, respectively. The economics of these systems would indicate that backgrounding of calves on swath grazed barley is a more efficient and low cost system compared to drylot.
3

Effect of backgrounding systems on winter and finishing performance, forage intake, carcass characteristics of beef calves and economic analysis

Kumar, Ravinder 31 March 2011 (has links)
A 2-year winter grazing and feedlot finishing trial (Exp 1) and subsequent in-situ nutrient disappearance study (Exp 2) were conducted to evaluate the effects of swath grazing forage barley (Hordeum vulgare, cv. Ranger) or foxtail millet (Setaria italica, cv. Golden German) compared to grass-legume hay fed in drylot on calf performance. In trial1 in each of 2 years, 120 spring born Angus calves (60 steers, 60 heifers) were fall weaned, stratified by weight, allocated into 20-head groups then assigned randomly to one of the three replicated (n=2) backgrounding (BG) systems. Backgrounding systems were (i) swath graze barley (BR); (ii) swath graze millet (ML); and (iii) bunk fed ground hay drylot (DL). Swath grazed calves were limit fed in 8 ha paddocks with 3 d grazing periods, using electric fencing for 96 d each year. All groups received a pelleted supplement at 0.62% BW. Calves were weighed at start, every 21 d and end of background period. Following the BG period, calves were placed in feedlot, separated by sex and BG treatment and fed a similar finishing ration and harvested at a targeted endpoint of 12 mm back fat. Forage samples collected every 21 d were analyzed for DM, CP and digestible energy (DE) and change in nutritive quality over the grazing period. DE content was greatest (P<0.05) for BR (2.6 Mcal/kg) and least for DL hay (2.2 Mcal/kg). Quality of all the three forages did not change over the grazing period except for an increase (P<0.05) in NDF of millet. Calf ADG was greatest (P <0.05) for BR compared to ML or DL, while dry matter intake (DMI) of the BR calves tended to be greater (P=0.11) than ML or DL calves. No treatment differences were observed in the finishing ADG (P>0.05) and carcass characteristics (P>0.05) of calves from the three backgrounding systems. In Exp 2, four dry ruminally cannulated Holstein cows fed ground grass hay were used in an in-situ degradability study to determine the extent of degradation and rumen kinetic parameters of the 3 forages used in Exp 1. Effective degradability of DM and CP iii were similar for barley and millet and greater (P<0.05) than grass legume hay while NDF degradability (P<0.05) of millet was greater than that of barley or grass legume hay. These findings indicate that swath grazing barley or foxtail millet fed to beef calves resulted in similar or decrease performance compared to a traditional drylot pen system. Cost of gain for the barley swath grazed backgrounding system calves was 43 and 60.5% lower compared to a swath grazed millet or drylot system, respectively. The economics of these systems would indicate that backgrounding of calves on swath grazed barley is a more efficient and low cost system compared to drylot.
4

The effect of supplementation strategy, stress level, and tall fescue type on performance of fall-weaned beef calves

Pickworth, Carrie Lynn 17 August 2005 (has links)
The beef cattle marketing structure imposes stress on calves due to weaning, transport, commingling, and adaptation to new diets, resulting in a weakened immune systems at the height of disease risk, frequently causing bovine respiratory disease. Backgrounding programs facilitate opportunities for calves to overcome stressors by building immunity, and adapting the rumen to high concentrate diets for improved feedlot performance. Four experiments were conducted to compare backgrounding strategies and effects of supplementation frequency performance and the effects of the ruminal environment. In Exp. 1, 48 weaned steers were used to investigate the effects of transportation and supplementation frequency, while in Exp. 2, 36 heifers were used to investigate only supplementation frequency. No differences in gains were observed due to transportation stress or supplementation frequency. Weaning stress resulted in elevated (P < 0.05) creatine kinase and neutrophil:lymphocyte ratios during the first week. In Exp. 3, 48 calves were used to compare the effect of tall fescue type on performance and health. Calves on novel endophyte fescue had higher ADG (P = 0.07) than on endophyte-infected fescue. Experiment 4 investigated the changes in ruminal environment due to supplementation frequency. No differences were observed between supplementation frequencies for ruminal pH, ammonia, or VFA concentration, and DM, or CP digestibility. Therefore, the rumen maintained a hospitable environment to promote bacterial protein synthesis and fiber digestion with every 48 h supplementation. Backgrounding calves with high fiber co-product supplements or on novel endophyte fescue can enhance calf performance. / Master of Science
5

Evaluation of By-product Feedstuffs, Level of Concentrate, and Selenium and Vitamin E Injections on Performance and Health of Beef Calves in Backgrounding Systems

Hutchinson, Karen Hallie 20 June 2003 (has links)
Weaning stress in young calves is often compounded with stress from transport, marketing, and commingling. The result is a weakened immune system, which can lead to increased incidence of diseases, especially bovine respiratory disease complex (BRDC). Backgrounding cattle post-weaning and prior to feedlot entry may alleviate some of the more common stresses and typically diminished feed intake. Five trials were conducted with a total of 228 weaned calves to evaluate different backgrounding systems. Drylot diets with 70:30 and 40:60 forage to concentrate total mixed rations with Se and vitamin E injections were studied. No differences were observed in daily gains or feed efficiency among treatments. Steers receiving Se injections had higher (P < 0.05) blood Se concentrations on d 7, 14, 28, and 42. Steers grazed four types of stockpiled pastures with previous pasture treatments: control, poultry litter fed to previous grazing cattle, poultry litter applied, and inorganic fertilizer. Supplements (16% CP) for each pasture treatment were none, soy hulls + SBM (0.5% BW), and corn + SBM (0.5% BW). On d 7, unsupplemented steers had higher (P < 0.05) daily gains than steers supplemented with corn + SBM. No differences were detected on any other day. Heifers grazed stockpiled fescue and were fed three 16% CP supplements: corn gluten feed + soy hulls (0.5% BW), corn gluten feed + soy hulls (1.0% BW), and soy hulls + SBM (0.5% BW). On d 14, heifers supplemented with soy hulls + SBM had higher (P < 0.05) cumulative daily gains. No other differences were detected in gains among treatments. Steers were allotted to four injection treatments: none, Se, vitamin E, and combination of Se and vitamin E. There were no differences in daily gain or blood Se concentrations on any day among all treatments. Steers grazed two pasture types: fescue and fescue + alfalfa, with the following injections: none, vitamin E, and Se. There were no differences in daily gains among all treatments. On d 7, 14, 28, and 42, steers receiving Se injections had higher (P < 0.05) blood Se concentrations. On d 7 and 14, steers grazing fescue pastures had higher serum alpha-tocopherol concentrations than steers grazing fescue + alfalfa pastures. There were no differences in serum alpha-tocopherol concentrations due to injection treatment on any day. No consistent differences were detected in forage and blood serum mineral concentrations in all trials. There were no differences in gains from by-product supplementation versus "traditional" corn-based supplementation, suggesting that by-product feedstuffs may be of value for backgrounding rations. Selenium and vitamin E supplementation did not have any significant effect on calf morbidity. / Master of Science
6

Information structure : empirical perspectives on theory

Karvovskaya, Lena, Kimmelman, Vadim, Röhr, Christine Tanja, Stavropoulou, Pepi, Titov, Elena, van Putten, Saskia January 2013 (has links)
The papers collected in this volume were presented at a Graduate/Postgraduate Student Conference with the title Information Structure: Empirical Perspectives on Theory held on December 2 and 3, 2011 at Potsdam-Griebnitzsee. The main goal of the conference was to connect young researchers working on information structure (IS) related topics and to discuss various IS categories such as givenness, focus, topic, and contrast. The aim of the conference was to find at least partial answers to the following questions: What IS categories are necessary? Are they gradient/continuous? How can one deal with optionality or redundancy? How are IS categories encoded grammatically? How do different empirical methods contribute to distinguishing between the influence of different IS categories on language comprehension and production? To answer these questions, a range of languages (Avatime, Chinese, German, Ishkashimi, Modern Greek, Old Saxon, Russian, Russian Sign Language and Sign Language of the Netherlands) and a range of phenomena from phonology, semantics, and syntax were investigated. The presented theories and data were based on different kinds of linguistic evidence: syntactic and semantic fieldwork, corpus studies, and phonological experiments. The six papers presented in this volume discuss a variety of IS categories, such as emphasis and contrast (Stavropoulous, Titov), association with focus and topics (van Putten, Karvovskaya), and givenness and backgrounding (Kimmelmann, Röhr).
7

KENTUCKY FEEDER CATTLE PRICE ANALYSIS: MODELS FOR PRICE PREDICTIONS AND GRAZING MANAGEMENT

Eldridge, Roger Wayne 01 January 2005 (has links)
Kentucky plays an important role in the complex U.S. beef cattle industry. Thisstudy focused on the feeder cattle production sector of Kentucky's beef cattle industry.Primarily a cow-calf state with a substantial backgrounding sector, Kentucky is a largesupplier of feeder cattle to the cattle finishing sector. Price relationships within themarket for Kentucky feeder cattle were examined using historical price data fromKentucky livestock auction markets. This research revealed many interesting pricerelationships that Kentucky producers may use in order to increase the profitability of thecow-calf and/or backgrounding operations. A segment of this research includes aGrazing Management Decision Tool which was constructed to enable producers toevaluate the potential profitability of various grazing scenarios using current marketforecasts.
8

Review and analysis of the 2008 National Stocker Survey

Roe, Janell January 1900 (has links)
Master of Science / Department of Agricultural Economics / Kevin C. Dhuyvetter / The 2008 National Stocker Survey defines the backgrounding/stocking of cattle as ―operations where calves are grown after weaning and/or preconditioning but before the feedlot. This includes calves purchased for this purpose as well as those retained by cow-calf producers post-weaning, but before marketing or retention through the feedlot. Backgrounding offers many benefits to farmers including, but not limited to, adding value to their feedstuffs—hay, grain, etc.—by feeding it to their cattle and potentially spreading risk by increasing marketing time or engaging in contracts with feedlots. However, producers also take on increased costs as it takes more time to wean, bunk-train, vaccinate, etc. compared to other operations in the cattle industry. This thesis attempts to analyze two studies using the 2008 National Stocker Survey. The first is how producer and operation characteristics—producer age, type of operation, income derived from backgrounding—relate to why producers find variables such as cattle prices, animal health management, marketing practices, and nutrition important. The second is how producer and operation characteristics relate to producers that use futures market contracts and options on futures. Binary and ordered logit models were used to find the statistical significance of the aforementioned studies.Since this survey was specifically designed to profile the stocking/backgrounding industry, some of the estimated models did not add a lot of value beyond the summary statistics for the various dependent variables. That is, the ordered logit models did not identify any strong relationships given that almost all of the producers that responded to these questions found feeder cattle prices, animal health management, marketing practices, and nutrition very important, which can be seen by analyzing the summary statistics. In addition, the binary logit models that were used for the futures market contract and options on futures models, found that the best way to pinpoint producers using either futures contracts or options was if producers were already using risk management strategies. Therefore, the survey’s purpose of profiling the stocker industry may be its best use.
9

Restricting dry matter intake of stocker calves and its subsequent effects on grazing, feedlot performance, and carcass characteristics

Anglin, Chad O'Neal January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Dale A. Blasi / An experiment was conducted to evaluate the effects of dry matter intake (DMI) restriction on early receiving performance by steers in a drylot and subsequent grazing performance, feedlot performance, and carcass characteristics. During the backgrounding period, crossbred, weanling steers (n = 329; initial BW = 191± 5.52 kg ) were randomly assigned to 1 of 4 DMI levels corresponding to ad libitum, 2.50% of BW (2.50%), 2.25% of BW (2.25%), and 2.00% of BW (2.00%) for 62 d. During the subsequent grazing period, the same steers were randomly assigned to 13 paddocks to graze for 90 d. Paddocks were stocked at 281 kg live weight per hectare. Initial steer BW were similar on each pasture and each backgrounding treatment was equally represented within a paddock. During the feedlot period, steers were finished at a commercial feedlot and were assigned to 1 of 4 pens according to their rank in BW. Entire pens were harvested when average steer BW reached 545 kg. During the backgrounding period, ad libitum-fed steers had greater (P < 0.001) ADG and final BW than other treatments; steers fed at 2.50 and 2.25% of BW had similar ADG and final BW and were greater (P < 0.001) than steers fed 2.00% of BW. During the grazing period, compensatory gain was observed in restricted DMI treatments. Steers fed at 2.00% of BW had greater (P = 0.006) ADG than ad libitum-fed steers but an ADG similar to that of the other restricted DMI treatments. Steers fed ad libitum, 2.50% of BW, and 2.25% of BW had similar final BW and steers fed 2.00% of BW had lesser (P < 0.001) final BW than other treatments. During the feedlot phase, steers fed 2.00% of BW were on feed longer (P < 0.05) than other treatments. Growth compensation during grazing illustrated that restricted feeding immediately prior to pasture grazing can reduce backgrounding costs.
10

Association of single nucleotide polymorphisms in the leptin gene and segregation by ultrasound backfat at weaning on carcass performance in steers

Breiner, Ryan Michael January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Twig T. Marston / One hundred ninety-three crossbred steers from two herds were used to determine the association of leptin gene polymorphisms and effects of feedlot management of lean and fat steers on carcass performance. Steers were sorted into FAT and LEAN groups by ultrasound backfat at weaning and randomly assigned to a finishing phase. Steers were assigned to a backgrounding phase (BACK) and were fed a forage-based diet for 90 days or directly entered a feedlot phase (FEED). Genotypes were determined by IGENITY® (Atlanta, GA) for a panel of nine single nucleotide polymorphisms (SNP) in the leptin gene (UASMS1, UASMS2, C963T, E2FB, A1457G, and A252T), leptin receptor (T945M), growth hormone receptor (G200A), and fat metabolism enzyme (K232A). Initial backfat (BF) means for the FAT and LEAN group were 3.4 mm and 1.8 mm, respectively. Mean on-test weight was heavier for FAT (306.5 kg) than LEAN (292.9 kg). Age-adjusted hot carcass weights (HCWT) were heavier for LEAN/BACK when compared to FAT/FEED and FAT/BACK (P<0.05). Dressing percent for the FAT/FEED group tended to be higher (P<0.10) over all groups except LEAN/BACK. Steers that went directly to the feedlot had higher marbling scores than backgrounded groups. FAT/FEED had higher 12th rib BF than the other contemporaries. None of the SNPs were useful for predicting ultrasound BF at weaning. Some association was detected with UASMS2 and HCWT (P<0.10) resulting in an 11 kg difference between genotype CC and CT (P<0.05). Five of the leptin polymorphisms (UASMS1, UASMS2, A1457G, C963T, and E2FB) were associated with adjusted carcass BF (P=0.01, 0.06, 0.01, 0.01, and 0.01, respectively) and calculated yield grade (P<0.01). A252T was associated with REA, and genotype TT was larger than AA and AT (P<0.05). This study suggests that segregation by initial fatness estimates and feedlot management strategies has the opportunity to increase HCWT by 35 kg. Sorting cattle upon feedlot entry by ultrasound BF and segregation using genetic markers are useful tools that can assist in the estimation of carcass composition in the live animal. With additional research, the possibility exists to incorporate genetic markers into feedlot selection to assist in marketing decisions.

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