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Incidence and severity of Arcanobacterium pyogenes injection site abscesses with needle and needle-free injection methodsGerlach, Bryce Mark January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / Nursery age pigs (n=198) were used to evaluate the difference in the occurrence of injection site abscesses between needle-free jet injection and conventional needle-and-syringe injection systems. Pigs were fed for 21 d prior to treatment administration to acclimate the pigs to the environment of the Kansas State University Segregated Early Weaning (SEW) unit. On d 21 each pig was injected with aluminum hydroxide adjuvant in the neck and ham with needle-free jet injection (Pulse Needle-Free Systems, Lenexa, KS) and conventional needle-and-syringe injection. Needle-free and conventional needle-and-syringe injections were randomly assigned to pig side yielding a total of 396 injections per treatment with a total of 792 injections sites. Immediately prior to injection, the external surface of the injection sites were contaminated with an inoculum of Arcanobacterium pyogenes, a bacterium commonly associated with livestock abscesses. The pigs were then fed for a period of 27 or 28 d. On d 27 or d 28 the pigs were humanely euthanized and sent to the Kansas State Veterinary Diagnostics Laboratory where necropsies were performed and the injection sites harvested for histopathological evaluation. The needle-free jet injection system was associated with more injection site abscesses than the conventional needle-and-syringe injection method for both neck (P=0.0625) and ham (P=0.0313) injection sites. Twelve abscesses were found at injection sites administered via needle-free jet injection method while only 1 abscess was found with the conventional needle-and-syringe injection method. 5 abscesses were found at the neck injection sites and 8 abscesses were found at ham injection sites. There were no significant differences seen in tissue granulation resulting from reaction to the adjuvant. In summary, the implementation of needle-free jet injection systems in market hog production will be beneficial to eliminate needles and needle fragments in meat products but, when in the presence of Arcanobacterium pyogenes, it may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork processing plants. Although more abscesses were associated with needle-free jet injection, their occurrence was observed at a very low rate given that all injection sites were intentionally contaminated prior to injection.
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Season of arrival and geographic region of origin affect feedlot performance, health, and carcass traits of Angus steersHands, Marisa Lynn January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Christopher D. Reinhardt / Angus steers (n = 17,919) fed at a single feedlot in southwestern Kansas between 1997 and 2007 were used to evaluate the effects of various demographic and phenotypic characteristics (season of arrival, geographic origin, health status, rate of gain, quality grade, and yield grade) on feedlot health, performance, and carcass traits. Cattle were not commingled and were predominantly preconditioned and backgrounded prior to shipment to the feedlot. Season of arrival was categorized as winter (December, January, and February), spring (March, April, and May), summer (June, July, and August), or fall (September, October, and November). Regions were: SC = Texas, Oklahoma, and New Mexico; C = Colorado and Kansas; NC = Montana, Nebraska, and Wyoming; and SE = Georgia, Mississippi, South Carolina, Tennessee, Virginia, and West Virginia. Steers that originated in SC had the poorest ADG (P < 0.01) and those originating in C had the greatest ADG, HCW, and quality grade (P < 0.01). Steers that arrived during fall had the lowest ADG and those arriving during the summer had the greatest morbidity (P < 0.01). Morbidity decreased and performance increased with increasing initial BW; quality grade was only minimally related to arrival BW in steers which were not treated for disease. After accounting for yield grade differences, the association between morbidity and carcass quality and between quality grade and heavier final BW and HCW were diminished, although ungraded cattle had lower ADG, final BW, and HCW (P < 0.01). Increasing yield grade from 1 and 2 to yield grade 3 increased percentage Choice by 12.1 points (P < 0.01); there was no additional gain in quality grade moving to yield grade 4 and 5. More rapidly gaining steers were heavier and fatter at marketing; this translated to greater quality grade in all but steers with initial BW > 375 kg. Performance was very similar among cattle which graded Prime, Choice, and Select, suggesting that producers do not need to choose between performance and quality grade; instead, much of the difference in quality grade can be explained by differences in yield grade.
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Effects of delayed steroid implanting on health, performance, and carcass quality in high health risk, auction market sourced feedlot steersMunson, Robert D. January 1900 (has links)
Master of Science in Biomedical Sciences / Diagnostic Medicine/Pathobiology / Daniel U. Thomson / Auction derived feeder calves (n=1,601; initial BW = 273.5 ± 4.7 kg) were used to examine the effects of delayed administration of the initial steroid implant on health, performance, and carcass characteristics of feedlot cattle. Steers were procured from multiple-source auction markets in the southeastern United States and shipped to a central Kansas feedyard over a 6 week period from December 2009 to January 2010. Steers were rested overnight prior to processing, then were randomly assigned, within arrival block, to 1 of 2 treatments: 1) implanted with Revalor-XS (40 mg estradiol and 200 mg trenbolone acetate) immediately upon arrival (ARRIVAL); or 2) implanted with the same implant after 45 d (DELAYED). Cattle were weighed on a group scale immediately following processing of each block. Feed deliveries were measured using load cells on feed trucks and recorded daily. Cattle were evaluated daily for morbidity and mortality by trained feedyard health personnel. Sick or injured cattle were removed from the home pen for further diagnosis and treatment. Individual animal health data were obtained and recorded daily. Final BW was calculated by dividing HCW by the average dressing percent of the pen. Carcass data (quality grade and yield grade) were obtained by USDA personnel; presence of lung lesions, pleural adhesions, and liver abscesses was evaluated by trained university personnel. Delaying the initial implant tended to reduce morbidity (24.7 vs. 28.5%; P = 0.13) and reduced railer rates (1.8 vs. 3.3%; P = 0.02); however, there were no effects of timing of implant administration (P ≥ 0.31) on rates of retreatment, mortality, lung lesions, or pleural adhesions. Implanting immediately upon feedlot arrival resulted in numerical improvements in ADG and feed conversion, but these differences were not statistical (P ≥ 0.56). Cattle implanted upon arrival had numerically greater HCW and yield grade vs. cattle implanted on d 45; however, these differences were not statistical (P ≥ 0.16). Delaying the initial implant 45 d did not influence animal health, performance parameters or carcass characteristics in high risk feeder calves.
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Use of corn- and sorghum-based distillers dried grains with solubles in diets for nursery and finishing pigsFeoli, Carolina January 1900 (has links)
Doctor of Philosophy / Department of Animal Sciences and Industry / Joe D. Hancock / Twelve experiments were completed to evaluate corn- and sorghum-distillers dried grains with solubles (DDGS) in diets for nursery and finishing pigs. In Exp. 1, corn-DDGS had 223 kcal/kg greater DE than sorghum-DDGS (P<0.02). In Exp. 2, pigs fed a corn-soy control diet had greater ADG, nutrient digestibility, HCW, and dressing percentage (P<0.02) and lower iodine value (IV) of jowl fat (P<0.001) than pigs fed diets with 40% DDGS. High-energy DDGS supported lower ADG, ADFI, and digestibility of DM (P<0.06) than moderate-energy DDGS, and sorghum-DDGS resulted in lower IV than corn-DDGS (P<0.001). In Exp. 3 and 4, addition of sodium bicarbonate to adjust dietary pH and electrolyte balance did not improve growth performance in nursery or finishing pigs (P>0.16) and adding molasses to improve palatability decreased (P<0.05) G:F for finishing gilts. In Exp. 5 and 6, enzyme additions improved nutrient digestibility in nursery (P<0.04) and finishing (P<0.01) pigs fed diets with high inclusion of DDGS. In Exp. 7, expander processing improved (P<0.02) ADG, G:F, and digestibility of DM, N, GE, and cellulose compared with standard steam conditioning of diets for nursery pigs, with the greatest response in G:F for pigs fed sorghum-DDGS (DDGS source × conditioning; P<0.02). In Exp. 8 and 9, expander conditioning improved G:F and dressing percentage (P<0.007) and digestibility of DM, N, and GE compared with standard conditioning (P<0.02), with the greatest response in digestibility of DM for the DDGS diets (diet × conditioning, P<0.01). In Exp. 10, 11, and 12, increasing tallow from 0 to 5% in diets with 40% DDGS improved (P<0.05) G:F. Dressing percentage was improved with addition of tallow and palm oil (P<0.08), but IV become worse (linear, P<0.06) as tallow was increased in the diet. Adding coconut oil improved growth performance and carcass firmness in pigs fed diets with 40% DDGS (P<0.01). In conclusion, growth performance and nutrient digestibility decreased with addition of DDGS to diets for nursery and finishing pigs. However, adding enzymes partially restored nutrient digestibility; expander conditioning improved G:F, dressing percentage, and nutrient digestibility; and adding coconut oil to diets with 40% DDGS improved G:F and carcass firmness.
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Relationship between castration and morbidity and their effects on performance and carcass qualityNewsom, Cora Jane January 1900 (has links)
Master of Science / Department of Agricultural Economics / Kevin C. Dhuyvetter / When purchasing feeder calves, bulls are typically discounted relative to steers. Most would agree that a discount is warranted but determining the appropriate discount to apply is considerably more difficult. Being able to calculate this discount under varying conditions would help stock operators maintain a certain level of profitability or recognize opportunities to make more profit when excessive discounts are being applied. The goals of this study were to determine how castration timing affects performance (as measured by average daily gain), morbidity, and carcass quality and how morbidity affects performance and carcass quality. Ordinary Least Squares regression and logit models were estimated to quantify the effects of various management and environmental factors on performance, morbidity, and carcass quality. These model estimates of production variables along with price and cost assumptions were used to calculate breakeven purchase prices and price discounts for bulls relative to steers, accounting for the possibility of contracting bovine respiratory disease, if owned for a short background period or if ownership is retained through slaughter. Model results confirm that late-castrated steers do indeed exhibit diminished performance and increased morbidity probabilities relative to early-castrated steers. Increased morbidity also decreases average daily gain. However, this study found that castration timing and morbidity during the backgrounding period have minimal effects on carcass quality, with morbidity only impacting hot carcass weight and castration timing significantly affecting days to market and only tending to impact hot carcass weight. Ultimately, based on 2009 market conditions, bulls should be discounted at feeder calf sales compared to steers. The average calf arrived at 459 pounds, and at this weight bulls should be discounted $4.69/cwt relative to the same weight steers. The discount increases to $5.37/cwt for 400 pound calves and drops to $4.20/cwt for 500 pound calves. If ownership is retained through slaughter, required discounts will change to $6.77/cwt, $4.91/cwt, and $7.55/cwt, respectively.
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Assessment of genetic markers for the improvement of beef quality and consistencyGill, Jennifer January 2010 (has links)
The overall aim of this thesis was to investigate the genetic control of beef quality in a commercial population of Aberdeen Angus-sired cattle with a view to trait improvement. The population studied included 500 Angus-cross animals, all with purebred Aberdeen Angus sires, from a selection of farms throughout Scotland. A number of carcass-related weight traits and taste panel assessed sensory traits were measured on these animals. A population of 265 Charolais cross cattle (all with purebred sires) was then used to explore the extrapolation of results across breeds. The first aim of this thesis was to investigate heritabilities for important carcass and meat quality traits and to assess the quality of a number of taste-panel derived meat quality traits by calculating three consistency statistics. Consistency statistics (parameter range 0 to 1) for the taste panel traits were moderately high, particularly for panel member consistency and reproducibility, with values ranging from 0.48 to 0.81 and 0.43 to 0.73, respectively. Estimated heritabilities were low for most of the sensory taste-panel-evaluated traits, where the maximum value was 0.16 for overall liking, but were higher for carcass traits where carcass weight heritability was 0.7. To perform these analyses it was first necessary to confirm paternity using a number of genetic markers. Therefore, a comparison of the power of both microsatellite and SNP markers for paternity exclusion was carried out to determine the more effective method. Results indicated that approximately three times as many SNP markers than microsatellite markers were required for parentage exclusion, and a panel of 15 microsatellite markers was used to assign paternity before subsequent data analysis was carried out. The remaining aims of this thesis centred on exploring genetic markers for carcass and meat quality. Firstly, the Angus animals were genotyped for the del11 myostatin mutation which was found to be segregating at a relatively low frequency (0.04) and was shown to be associated with a 17.4 kg increase in carcass weight (P < 0.05) in the heterozygous animals when compared to the homozygous wild-type animals. By analysing the haplotype associated with the mutant allele, it was determined that there have been at least two separate introductions of the mutant allele into the Aberdeen Angus breed. A number of SNPs were also tested for their effects on the carcass and meat quality traits in the Angus animals. The SNPs fell into two groups: eight that have been incorporated into commercially available tests and a further 28 from alternative candidate genes that have effects in different breeds and species. In total, 17 SNPs significantly affected at least one of the traits measured. Of these significant associations, a number have been seen previously, such as the association between calpain and tenderness (P = 0.01) and growth hormone and eye muscle area (P = 0.05), and some of which were novel, such as the association between growth hormone receptor and steak odour (P = 0.02) and corticotrophin releasing hormone and gristle distance from fat (P = 0.004). A further six SNPs, identified by resequencing of the malic enzyme 1 (ME1) and small heterodimer partner (SHP) genes, were tested for their effects on the traits measured in this thesis. Five of the SNPs, including one which caused a non-synonymous amino acid change, had a significant effect on at least one of the traits tested including fat class (P = 0.002), eye muscle area (P = 0.01), sirloin weight before maturation (P = 0.03), sirloin steak tail length (P = 0.004) and juiciness (P = 0.004) where the effect sizes were 1.79 units, 565 mm2, 0.36 kg, 17.12 mm and 0.23 taste panel units, respectively. To assess the effect of the genotyped SNPs on intramuscular fat (IMF), a simple method of visible IMF quantification in the sirloin steak was developed using digital photographs and an image analysis program. Results showed that two SNPs in the calpain gene, known to be linked with an increase in meat tenderness, were associated with an increase in visible IMF% and the del11 mutation was associated with a reduction in visible IMF%. The heritabilities, SNP association validations and novel SNP-trait associations identified in this thesis provide tools for use in breeding programs, possibly via marker assisted selection to improve meat quality traits. However, the results seem breed-specific, as most of the significant effects were not replicated in the Charolais population.
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SPECIALTY POULTRY PRODUCTION: IMPACT OF GENOTYPE, FEED STRATEGIES, ALTERNATIVE FEEDSTUFFS, AND DIETARY ENZYMES ON THE GROWTH PERFORMANCE AND CARCASS CHARACTERISTICS OF HERITAGE BREED CHICKENSFisher, Tatijana 01 January 2016 (has links)
There is a growing market for specialty poultry production using alternative genotypes and management systems. However, producers interested in specialty poultry production face several challenges. One challenge is that little published data exists regarding the growth and production parameters for alternative genotypes like slow-growing meat strains and heritage breeds. To address this challenge, research at the University of Kentucky examined the effect of feed strategies, alternative feedstuffs, and dietary enzymes on the growth and performance of heritage breeds of chicken used for either egg- or meat-production. The first trial documented the growth and nutrient intake of pullets from three heritage breeds (Rhode Island Red, Barred Plymouth Rock, and Black Australorp) and three egg-laying strains (Red Star, Black Star, and ISA Brown) on a self-selection feeding program through nineteen weeks of age. The second trial documented the growth and nutrient intake of males from those same three heritage breeds, a slow-growing meat-type strain (Red Ranger), and males and females from a fast-growing meat-type strain (Cornish Cross). Birds used a self-selection feeding program and were grown to a common weight of 2300 grams. Carcass characteristics of these birds were evaluated in the third trial. The fourth trial evaluated the partial replacement of corn and soybean meal with alternative feedstuffs (field peas, buckwheat, and flax seed) and dietary enzymes on the performance of straight-run commercial broilers and two alternative breeds of chickens: males from a Black Sex-Link cross and straight-run Rhode Island Reds. The fifth trial examined the use of sorghum and field peas to completely replace corn and soybean meal in formulated diets for two heritage breeds (Rhode Island Red and Barred Plymouth Rock). Results of these trials showed that heritage breed pullets had similar growth parameters and nutrient intake as commercial egg-laying strains. Heritage breed cockerels grew significantly slower and exhibited poorer feed efficiency than meat-type birds, but seemed to tolerate low nutrient density diets better. Overall, the findings of these studies could help producers interested in raising slow-growing meat-type chickens and heritage breeds create accurate business plans and determine if they can profitably produce meat and/or eggs for niche markets.
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Phenotypic and genetic relationships among temperament, immune, and carcass traits in beef cattleBates, Kerri E. January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Jennifer Minick-Bormann / Cattle temperament has historically influenced selection decisions due to ease of handling. However, temperament may also influence economically relevant traits. The purpose of this study was to investigate relationships between temperament, Bovine Respiratory Disease (BRD) incidence, and resulting carcass merit in feedlot steers. Across a two year period, 2,870 crossbred steers were shipped from a single ranch source to a feedlot. At the time of feedlot placement, as well as at the time of reimplantation, temperament was measured via chute score (CS) and exit velocity (EV). Blood samples were taken upon arrival to the feedlot to determine circulating concentrations of interleukin 8 (IL-8) and cortisol, both of which are involved in immune function. Performance traits, including weight and gains, were measured at feedlot placement (d 0), reimplantation (d 73-100), and again 59 to 70 days later. Recorded carcass data included HCW (HCW), USDA yield grade (YG), marbling score (MS), ribeye area, and lung scores. Phenotypic statistical analysis was performed with SAS statistical software (SAS Inst., Inc., Cary, NC) and genetic parameters were estimated using ASREML (Ver. 3.0, VSN International, Ltd., Hemel Hempstead, UK). The pedigree file included records of 7,177 animals with up to 7 generation of pedigree. Contemporary group (CG, n=11) included initial ranch unit, date of arrival to the feedlot, feedlot pen, and processing dates. Fixed effects included in the model were pre-feedlot entry BRD treatment and CG. Cattle with higher CS at placement subsequently had more BRD incidence (P < 0.01). There was a positive phenotypic correlation between placement CS and blood cortisol concentrations (r = 0.07; P< 0.01), and cattle with higher cortisol concentration contracted BRD more often than their calmer peers (P < 0.05). Circulating IL-8 concentration had no influence on feedlot health. At the time of reimplantation, cattle that had been treated for BRD in the feedlot had lower chute scores (P < 0.001). Heritability estimates for CS at placement, EV at placement, CS at reimplantation, and EV at reimplantation were 0.23, 0.17, 0.19, and 0.27, respectively. BRD incidence had a negative genetic correlation with all measures of temperament recorded at the second processing period.
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Avaliação de bovinos Nelore submetidos a períodos de restrição alimentar, durante a terminação /Cerdótes, Liliane. January 2007 (has links)
Orientadora: Jane Maria Bertocco Ezequiel / Banca: Alexandre Amstalden Moraes Sampaio / Banca: Antonio Tadeu de Andrade / Banca: Juliana Borsari Dourado Sancanari / Banca: Fábio Prudêncio de Campos / Resumo: Este estudo teve por objetivo avaliar a possibilidade de obter dois ganhos compensatórios (GC) durante a terminação em confinamento de animais machos inteiros da raça Nelore. O primeiro, no início do confinamento, e o segundo, após estes sofrerem restrição alimentar qualitativa (RAQ) por 28 ou 56 dias e realizar a apreciação econômica da alimentação durante a terminação, comparar o comportamento ingestivo e os componentes não integrantes da carcaça e as características quantitativas e qualitativas da carcaça e da carne. Os tratamentos foram: SRAQ - Animais sem RAQ, recebendo dieta contendo em média 13,08% de proteína bruta (PB) e 69,78% de nutrientes digestíveis totais (NDT), a base de silagem de milho e concentrado do início ao final do experimento, obedecendo uma relação volumoso:concentrado de 62,5:37,5; RAQ28 - Animais recebendo a mesma dieta do tratamento SRAQ, porém com RAQ durante 28 dias, em que os animais receberam apenas silagem de milho com 8,13% PB e 64,27% NDT e RAQ56 - Animais recebendo mesma dieta do tratamento SRAQ, porém com RAQ por 56 dias, em que os animais receberam apenas a silagem de milho. Durante à RAQ os animais dos tratamentos RAQ28 e RAQ56 apresentaram menor consumo de matéria seca diária (CMSD) e ganho médio diário (GMD), em relação aos animais do tratamento SRAQ. Nos períodos subseqüentes a RAQ, os animais submetidos a RAQ apresentaram CMSD numericamente maior e GMD superior aos animais do tratamento SRAQ. Ocorreu maior GMD dos animais no segundo período (1,873 kg) em relação ao primeiro (0,933 kg), denotando GC no inicio do confinamento. Os animais do tratamento RAQ28 apresentaram menor GC diário no período subseqüente a RAQ do que aqueles do tratamento RAQ56 (37,9 contra 84,8%) quando comparado aos animais do tratamento SRAQ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work was carried out to evaluate the possibility of obtaining two compensatory gains (CG) in Nellore bulls, one at the beginning of feedlot finishing and another after subjecting bulls to qualitative feeding restriction (QFR) for 28 or 56 days. Feeding economic evaluation was performed during feedlot finishing, compare the ingestive behavior and evaluate non-carcass components, as well as quantitative and qualitative traits of carcass and meat. The following treatments were studied: NQFR . Animals with no feed restriction from the beginning to the end of the experiment; QFR28 . Animals subjected to QFR for 28 days; QFR56 - Animals subjected to QFR for 56 days. Bulls subjected to 28 or 56 days of QFR showed lower daily consumption of dry mass (DCDM) and daily mean gain (DMG) during feeding restriction in comparison to NQFR bulls. After QFR, animals subjected to feeding restriction showed higher DCDM and DMG than NQFR bulls. A DMG increase was observed from the first (0.933 kg) to the second (1.873 kg) period, which indicates CG at the beginning of feedlot finishing. QFR28 bulls showed lower daily CG after QFR (37.9%) than QFR56 bulls (84.8%). The final weight was similar between treatments, indicating QFR for 28 or 56 days followed by no feeding restriction is a viable management alternative in feedlot finishing. Costs and liquid incomes were similar between treatments at the end of the experiment. Anticipating slaughter in 28 days resulted in higher liquid income in NQFR and QFR28, in comparison to the income obtained at the end of the experiment. Animals under QFR spent more time resting and tended to ruminate for more time during the 24h-period, if compared to bulls with concentrate diet. In general, animals spent more time feeding, ingesting water and consequently defecating and urinating during daytime. At night 73.75% of the time was spent with lying rumination or resting...(Complete abstract, acess undermentioned eletronic adress) / Doutor
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Anticorpos policlonais e monensina sódica na alimentação de bovinos jovens confinados com dietas de alto concentrado /Millen, Danilo Domingues, 1981- January 2010 (has links)
Orientador: Mário De Beni Arrigoni / Banca: Telma Terezinha Berchielli / Banca: Mário Sartori Bueno / Banca: Rafael da Costa Cervieri / Banca: José Roberto Sartori / Resumo: O objetivo deste estudo foi estudar os efeitos da suplementação do preparado de anticorpos policlonais (PAP) ou monensina sódica (MON) sobre o desempenho, características de carcaça, perfil metabólico sanguíneo, flutuação da ingestão de matéria seca (IMS) e incidências de rumenites e abscessos de fígado. O delineamento experimental foi inteiramente casualizado em arranjo fatorial 2 × 2, com seis repetições por tratamento, nos quais 48 bovinos machos inteiros de cada grupo genético (GG) avaliado [Brangus (BR) ou Nelore (NE)] foram alimentados com dietas contendo MON ou PAP fornecidos diariamente nas doses de 30 e 300 mg/kg de MS, respectivamente. Os animais passaram por três fases durante o estudo: adaptação (ADAP), crescimento, e terminação. As dietas fornecidas nestes períodos continham 55, 70 e 85% de concentrado, respectivamente. Não foi observado (P > 0,05) efeito principal dos aditivos alimentares (AA) sobre a maioria das características de desempenho, com exceção à IMS em quilos e em porcentagem do peso vivo, onde bovinos recebendo MON apresentaram (P < 0,05) menores IMS. Foi observado (P < 0,01) efeito principal dos AA e dos GG sobre as concentrações de bicarbonato, total de CO2 e excesso de base no fluído extra-celular, onde bovinos recebendo PAP, e aqueles da raça BR, apresentaram maiores concentrações desses metabólitos no sangue. Animais que receberam PAP e aqueles da raça BR, apresentaram maiores (P < 0,01) valores de pH na fase de ADAP que animais suplementados com MON (7,427 vs. 7,400) e animais NE, respectivamente. Bovinos BR apresentaram (P < 0,01) maior ganho de peso diário que bovinos NE em ambas as fases, contudo conversão alimentar similar (P > 0,05). Por outro lado, bovinos NE mostraram maior (P < 0,05) incidência de lesões ruminais. Assim sendo, a suplementação de PAP pode ser uma eventual alternativa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study, conducted at the São Paulo State University feedlot, Botucatu Campus, Brazil, was designed to test monensin (MON) and a polyclonal antibody preparation (PAP) against rumen bacteria on feedlot performance of Brangus (BR) and Nellore (NE) cattle. The experiment was designed as a 2 × 2 factorial arrangement using repeated measures over time, replicated 6 times (4 bullocks/pen), in which 48 8-mo-old bullocks of each of two breeds (BD) evaluated were fed diets containing either MON at 30 mg•kg-1 or PAP at 300mg•kg-1 of dry matter (DM). Measures over time were taken according to the phase and level of concentrate fed during the study: 55, 70 and 85%. Phases were named adaptation (AD), growing (GR), and final (FN), respectively. No significant (P > 0.05) feed additives (FA) main effect was observed for any of the feedlot performance variables, with the exception (P < 0.05) of DM intake expressed in kg (PAP= 7.60; MON=7.24) and in % of body weight (PAP= 2.11; MON=2.03). Feeding MON led to greater (P < 0.05) subcutaneous fat deposition throughout the study, and decreased (P < 0.05) the final rib eye area (RBA). As a result a reduced (P < 0.05) RBA deposition, mainly in GR phase, it was observed when feeding MON was compared to feeding PAP. A significant (P < 0.01) FA and BD main effects were found for bicarbonate, total CO2, and base excess in extracellular fluid, where bullocks receiving PAP, and those BR cattle, presented greater concentrations of these metabolites in the blood. Likewise, BR cattle and bullocks receiving PAP had (P < 0.01) higher blood pH in the AD phase than NE cattle and bullocks fed MON (7.427 vs. 7.400), respectively. BR had greater (P < 0.01) average daily gain in GR and FN phases, but similar (P > 0.05) feed conversion was observed. On the other hand, NE bullocks presented greater (P < 0.05) incidence of rumenites. Thus, feeding PAP may... (Complete abstract click electronic access below) / Doutor
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