Made available in DSpace on 2014-06-11T19:27:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-18Bitstream added on 2014-06-13T18:56:22Z : No. of bitstreams: 1 surge_ca_me_botfmvz.pdf: 181478 bytes, checksum: e9a62b9da5fa2ad5b29ae7e37c0844b8 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Objetivou-se com o presente estudo avaliar a precocidade de cordeiros de quatro grupos genéticos terminados em confinamento em depositar gordura de cobertura subcutânea,preconizada entre 3 e 4 mm. Foram utilizados 48 cordeiros machos não castrados, sendo 12 de cada um dos seguintes grupos genéticos: Ile de France (IF), Hampshire Down (HD), Texel (TE) e Suffolk (SU) com peso corporal e idade média inicial de 22,27±4,70 kg e 80 dias respectivamente. Os animais foram pesados no início do experimento e a cada 14 dias para avaliação do consumo voluntário e evolução do peso. Junto às pesagens foram obtidas medidas de espessura de gordura subcutânea (EGS) por meio do equipamento de ultrassom, sendo o parâmetro adotado como critério de abate (EGS entre 3 e 4 mm). Não houve diferença (P>0,05) entre os grupos genéticos para ingestão de matéria seca (0,933 kg) e ganho de peso médio diário (0,170 kg). A conversão alimentar foi diferente apenas entre animais Texel e Suffolk (4,84 e 7,72 :1, respectivamente). Não houve diferença (P>0,05) para as características de carcaça entre todos os grupos genéticos. Cordeiros Hampshire Down foram mais precoces que Ile de France, Texel e Suffolk na deposição de gordura subcutânea da carcaça (entre 3 e 4 mm) avaliada in vivo por ultrassom quando terminados em confinamento / The objective of this study was to evaluate the precocity of lambs from four genetic groups finished in feedlot lambs on depositing subcutaneous fat thickness between 3 and 4 mm. It was used 48 non-castrated lambs being 12 from each genetic groups: Ile de France (IF), Hampshire Down (HD), Texel (TE) e Suffolk (SU) with body weight and initial mean age of 22.27±4.70 kg and 80 days respectively. The animals were weighed on the beginning and every 14 days to evaluate the dry matter intake and weight gain. Along the weights were obtained measures of subcutaneous fat thickness (SFT) by ultrasound equipment. The slaughter criterion was the fat thickness between 3 and 4 mm. There was no difference (P>0.05) between genotypes for dry matter intake (DMI: 0.933 kg/day) and average daily weight gain (0.170 kg). The feed was different only between Texel and Suffolk (4.84 and 7.72 :1, respectively). There was no difference (P>0.05) for carcass traits among all genetic groups. Hampshire Down lambs when evaluated on feedlot were more precocious than Ile de France, Texel and Suffolk to deposit subcutaneous fat in carcass (3 to 4 mm) evaluated in vivo by ultrasound

Orientador: André Mendes Jorge / Banca: Simone Fernandes / Banca: Rafael Silvio Bonilha Pinheiro / Resumo: Objetivou-se com o presente estudo avaliar a precocidade de cordeiros de quatro grupos genéticos terminados em confinamento em depositar gordura de cobertura subcutânea,preconizada entre 3 e 4 mm. Foram utilizados 48 cordeiros machos não castrados, sendo 12 de cada um dos seguintes grupos genéticos: Ile de France (IF), Hampshire Down (HD), Texel (TE) e Suffolk (SU) com peso corporal e idade média inicial de 22,27±4,70 kg e 80 dias respectivamente. Os animais foram pesados no início do experimento e a cada 14 dias para avaliação do consumo voluntário e evolução do peso. Junto às pesagens foram obtidas medidas de espessura de gordura subcutânea (EGS) por meio do equipamento de ultrassom, sendo o parâmetro adotado como critério de abate (EGS entre 3 e 4 mm). Não houve diferença (P>0,05) entre os grupos genéticos para ingestão de matéria seca (0,933 kg) e ganho de peso médio diário (0,170 kg). A conversão alimentar foi diferente apenas entre animais Texel e Suffolk (4,84 e 7,72 :1, respectivamente). Não houve diferença (P>0,05) para as características de carcaça entre todos os grupos genéticos. Cordeiros Hampshire Down foram mais precoces que Ile de France, Texel e Suffolk na deposição de gordura subcutânea da carcaça (entre 3 e 4 mm) avaliada in vivo por ultrassom quando terminados em confinamento / Abstract: The objective of this study was to evaluate the precocity of lambs from four genetic groups finished in feedlot lambs on depositing subcutaneous fat thickness between 3 and 4 mm. It was used 48 non-castrated lambs being 12 from each genetic groups: Ile de France (IF), Hampshire Down (HD), Texel (TE) e Suffolk (SU) with body weight and initial mean age of 22.27±4.70 kg and 80 days respectively. The animals were weighed on the beginning and every 14 days to evaluate the dry matter intake and weight gain. Along the weights were obtained measures of subcutaneous fat thickness (SFT) by ultrasound equipment. The slaughter criterion was the fat thickness between 3 and 4 mm. There was no difference (P>0.05) between genotypes for dry matter intake (DMI: 0.933 kg/day) and average daily weight gain (0.170 kg). The feed was different only between Texel and Suffolk (4.84 and 7.72 :1, respectively). There was no difference (P>0.05) for carcass traits among all genetic groups. Hampshire Down lambs when evaluated on feedlot were more precocious than Ile de France, Texel and Suffolk to deposit subcutaneous fat in carcass (3 to 4 mm) evaluated in vivo by ultrasound / Mestre

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Since the 1960’s liver abscess incidence and severity have been identified as a problem associated with feeding high concentrate finishing rations to feedlot cattle. Liver abscesses lead to decreased feedlot performance and decreased carcass value. Tylosin phosphate is a macrolide antibiotic commonly used by feedlots throughout the United States and has been shown to successfully control liver abscesses. In 2013, the FDA issued Guidance for Industry #213, which encourages reduced usage of medically important classes of antibiotics, such as macrolides, in animal feed. This will be achieved by implementing veterinary oversight of these drugs via Veterinary Feed Directives (VFD). Thus, it is of importance to find alternative strategies to reduce usage of tylosin in finishing rations to control liver abscesses. One strategy that has been suggested is increasing dietary roughage concentration. However, this isn’t a viable option as increasing dietary roughage concentration not only leads to a decline in feedlot performance, hot carcass weight, and dressing percentage, but also has an environmental impact. Available research has also indicated that increasing dietary roughage has no impact on liver abscess incidence or severity. Our research objective was therefore to identify alternative strategies to reduce liver abscess incidence. Our first trial evaluated the impact of antioxidants on liver abscess incidence and severity. Treatments consisted of a control treatment (basal diet containing 200 IU/d α-tocopherol acetate), and an antioxidant treatment (basal diet containing 2000 IU/d α-tocopherol acetate and 500 mg/d crystalline ascorbate). Treatments were randomly assigned to 390 crossbred heifers. No differences in feedlot performance were detected; however, there was a tendency for improved feed intake (P = 0.075) and feed efficiency (P = 0.066) for heifers that received the antioxidant treatment. An increased number of yield grade 3 carcasses (P = 0.03) and fewer yield grade 1 carcasses (P < 0.01) was observed in the antioxidant treatment group. No differences were detected between treatments for other carcass characteristics or liver abscess incidence and severity. Another trial evaluated intermittent tylosin feeding and its impact on liver abscess incidence and antimicrobial resistant Enterococcus spp. when compared to continuous tylosin feeding. One of 3 treatments were randomly assigned to 312 crossbred steers: negative control (no tylosin fed throughout the feeding period); positive control (tylosin fed throughout the feeding period); or intermittent treatment (tylosin fed intermittently throughout the feeding period: 1week on, 2 weeks off). Fecal samples were collected on day 0, 20, and 118 to characterize antimicrobial resistant Enterococcus spp. By design, the intermittent treatment consumed 60% less tylosin than the positive control group. No differences were detected between treatments for feedlot performance. Liver abscess incidence was greatest for the negative control, and least for the positive control and intermittent treatments, with no difference being detected between the latter two treatments (P = 0.716). Antimicrobial resistance was unaffected by treatment, but was affected by sampling time. We concluded that supplementing antioxidants is not a viable option to reduce liver abscess incidence and severity, and that tylosin usage can be decreased without adversely affecting performance or liver abscess incidence.

Within the South African feedlot industry, there are currently several different roughage sources available for use in feedlot finishing diets. To evaluate the influence of dietary energy and fibre source on rumen function in feedlot animals, four roughage sources (wheat straw, Eragrostis curvula hay, cottonseed hulls and maize silage) were used in combination with hominy chop or dry rolled maize in two experiments. Four Beefmaster steers (270kg ±15kg) fitted with ruminal cannulae were used in two separate experiments in a 4 x 4 Latin square design. Experiment 1 was conducted to evaluate each roughage source in combination with hominy chop namely: wheat straw, hominy chop (WSHC); Eragrostis hay, hominy chop (EHHC); cottonseed hulls, hominy chop (CHHC); and maize silage, hominy chop (MSHC). Experiment 2 was conducted to evaluate each roughage source in combination with dry rolled maize (DRM) namely: wheat straw, dry rolled maize (WSDRM); Eragrostis curvula hay, dry rolled maize (EHDRM); cottonseed hulls, dry rolled maize (CHDRM); and maize silage, dry rolled maize (MSDRM). Diets were designed to contain equal amounts of energy, starch, crude protein, neutral detergent fibre (NDF) and 7.5% roughage source in both experiments. All diets were evaluated for particle size distribution through the Penn State Forage Particle Separator (PSPS) and ruminal fermentation parameters (volatile fatty acid composition, VFA; rumen ammonia nitrogen, NH3-N; lactate and ruminal pH) were compared for each experiment. Results from experiment 1 showed that animals fed the MSHC had the lowest (P<0.05) concentration of VFA while animals fed the CHHC diet produced the highest (P<0.05) ruminal propionate concentration, lowest (P<0.05) acetate: propionate ratio and had the lowest (P<0.05) ruminal pH during the 24h observation period. Time intervals below pH 5.6 and pH5.2 for CHHC was 940 minutes (P<0.05) and 388.75 minutes respectively. Measurements for rumen NH3-N concentrations and lactate did not differ between treatments. Results from experiment 2 revealed that animals fed WSDRM had numerically the lowest concentration of VFA and differed (P<0.05) from CHDRM and MSDRM diets. Propionate and acetate as well as A:P ratios for CHDRM were numerically higher than other treatments but differed (P<0.05) from the WSDRM diet. Rumen NH3-N concentrations did not differ but lactate concentrations were higher for EHDRM when compared to the MSDRM and WSDRM diets (P>0.05). Ruminal pH observations showed steers consuming the MSDRM diet to have the lowest mean ruminal pH of 5.53 which differed (P<0.05) from the WSDRM diet with a mean ruminal pH of 6.1. Time periods spent below pH 5.6 and 5.2 for steers consuming the MSDRM diet was highest at 703.75 and 306 minutes respectively and differed from steers consuming the WSDRM diet. Results from these experiments indicated that different roughage sources in combination with specific energy sources resulted in different rumen fermentation characteristics. Evaluation of particle size distribution from the roughage source, particularly the large pool (upper and middle sieve sizes on PSPS) further revealed that particle size alone does not explain all variation in fermentation patterns alone but the digestible NDF as percentage of total NDF for these fractions could be a valuable predictor for chewing and rumination activity to ultimately establish a more optimal ruminal pH. / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Animal and Wildlife Sciences / unrestricted

Hot-iron branding on the upper hind limb in beef feedlot calves is a usual part of the processing procedure at arrival in many feedlots in South Africa. However, cheek branding is becoming more popular in feedlots due to ease of restraint and better visibility of the brand mark. However, the welfare aspects of cheek branding compared to leg branding have not been investigated. By monitoring physiological and behavioural markers this study was conducted to determine potential stress-related differences between feedlot calves which are branded on the leg, those branded on the cheek and control (sham-branded) animals. Thirty weaned crossbred beef calves, recently arrived at a commercial feedlot, were habituated to handling in a crush for seven days and then randomly divided into three groups of ten. Group A was branded on the cheek, Group B on the hind leg and Group C was sham-branded with a room temperature iron. Group C was further divided into two groups (n = 5) that were either sham-branded on the cheek or on the leg. Blood was collected at 0, 30, 60, 90 and 120 minutes after branding for serum cortisol determination with a commercial radioimmunoassay kit. In addition, faeces were collected from all animals on the day after arrival, as well as at day seven, two and one prior to branding, on the day of branding and for seven consecutive days. Faecal glucocorticoid metabolite levels were determined using a group-specific enzyme immunoassay measuring 11,17-dioxoandrostanes (11,17-DOA). Other outcomes monitored included behavioural traits for seven days after branding, individual average daily weight gain (ADG), morbidity and mortality during the feedlot period and histopathological evaluation of the brand mark on the skin after slaughter. Faecal 11,17-DOA concentrations were higher the day after transport than the day after branding (P < 0.001) indicating higher circulating levels of cortisol during transport. Compared to pre-branding levels, serum cortisol was not significantly higher at 30 minutes after branding in all three groups but hormone levels dropped significantly at 60 minutes post-branding. Concentrations at 90 and 120 minutes were not significantly different from pre-branding concentrations in all three groups. The quantifiable rise seen between 60 and 90 minutes post-branding could have been due to the extended time (up to 2.5 hours) spent in the crush. There were no statistically significant differences in blood cortisol or faecal 11,17-DOA between the cheek, leg or sham branded groups at any time. Vocalization occurred more frequently at the time of branding in the cheek branded group than in either the leg branded (P = 0.030) or the control group (P < 0.001). There were also no significant differences in other behavioural indices between the three groups. Faint brand marks could be seen at the time of slaughter (74 days after branding) on five animals from the leg branded group. No cheek brands were visible. No scarring was seen on histopathological examination. No significant differences were seen in the ADG, and there were no morbidities or mortalities. In conclusion, using the methods described, there were no obvious differences in serum cortisol levels, faecal 11,17-DOA levels, behavioural indicators of pain or production outcomes between feedlot calves branded on the cheek, the leg, or sham branded. / Dissertation (MMedVet)--University of Pretoria, 2012. / Production Animal Studies / unrestricted

Master of Science / Department of Clinical Sciences / Daniel Ulan Thomson / Consulting veterinarians (CV; n=23) representing 11,295,000 head of cattle on feed in the United States and Canada participated in a beef cattle health and well-being recommendation survey. Veterinarians were directed to an online survey to answer feeder cattle husbandry, health and preventative medicine recommendation questions. The CV visited their feedyards 1.7 times per month. All CV train employees on cattle handling and pen riding while only 13% of CV speak Spanish. All CV recommend IBR and BVD vaccination for high-risk (HR) calves at processing. Other vaccines were not recommended as frequently by CV. Autogenous bacterins were recommended by 39.1% CV for HR cattle. Metaphylaxis and feed-grade antibiotics were recommended by 95% and 52% of CV, respectively, for HR calves. Banding was more frequently recommended than surgical castration as calf body weight increased. The CV recommended starting HR calves in smaller pens (103 hd/pen) and allowing 13 inches/hd of bunk space. The CV indicated feedlots need to employ one feedlot doctor per 7,083 hd of HR calves and one pen rider per 2,739 hd of HR calves. Ancillary therapy for treating respiratory disease was recommended by 47.8% of CV. Vitamin C was recommended (30.4%) twice as often as any other ancillary therapy. Cattle health risk on arrival, weather patterns and labor availability were most important factors in predicting feedlot morbidity while metaphylactic antibiotic, therapy antibiotic and brand of vaccine were least important. This survey has provided valuable insight into feeder cattle health recommendations by CV and points to needed research areas.

In this study, 14 typical South African feedlot bulls received no beta-adrenergic agonist for the last 30 days of the finishing period (C), 14 received 120 mg R-salbutamol per animal per day for the last 30 days of the finishing period (S30), 13 received 120 mg Rsalbutamol per animal per day for the last 40 days of the finishing period (S40) and the last group of 13 bulls received 60 mg zilpaterol hydrochloride per animal per day for the last 30 days of the finishing period (Zh). All animals were slaughtered after a 3-day withdrawal period. Parameters included weight gain, feed intake, feed conversion rate, warm and cold carcass mass, dressing %, subcutaneous fat thickness, hide yield %, internal carcass fat distribution, % bone, % fat and % muscle of the prime rib-cut, carcass classification code, conformation, compactness, post-mortem carcass pH profiles, cooking loss, shear force, blood urea nitrogen, creatinine and residue levels of the beta-adrenergic agonists. No differences were observed between any of the four treatment groups concerning live feedlot performance. Bulls receiving the S30 and Zh treatments had lower internal carcass fat distribution compared to C bulls (P <0.05). Bulls receiving the S40 treatment had a lower % fat in the prime rib-cut compared to Zh bulls (P <0.05). Carcasses from S30 bulls had higher pH values 24 hours post mortem compared to carcasses from Zh bulls (P <0.01). Meat samples from Zh bulls had higher shear force, which indicates less tender meat, compared to samples from S40 bulls (P <0.05). Change in serum creatinine levels increased only in Zh treated bulls from the start to the end of treatment and may reflect a higher protein turnover in Zh bulls. The results of this study indicate that R-salbutamol has a more pronounced effect on fat metabolism in feedlot bulls compared to zilpaterol hydrochloride, while zilpaterol hydrochloride has a more pronounced effect on protein metabolism. The residue levels in samples of the liver, kidney, muscle and feaces from zilpaterol hydrochloride and R-salbutamol treated bulls were well below acceptable limits. / Dissertation MSc(Agric)--University of Pretoria, 2014 / gm2015 / Animal and Wildlife Sciences / MSc(Agric) / Unrestricted

Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Two trials were conducted to evaluate effects of crude glycerin, a byproduct of the biodiesel industry, on feedlot performance, carcass characteristics, and diet digestibility in cattle. A third study was conducted to investigate the use of glycerin as a solvent in Maillard reaction processes used to manufacture value added protein meal. In trial 1, crossbred yearling heifers were fed low levels of glycerin (0, 0.5, or 2% of diet DM) in corn finishing diets, or diets that combined corn with soybean hulls and wet distiller’s grains (0 or 2% glycerin). Results indicated that feeding glycerin decreased DMI (P = 0.04), and feeding byproducts increased DMI (P < 0.01) when compared to control without byproducts or glycerin. Feeding byproducts or glycerin decreased the percentage of carcasses that graded USDA Choice or higher (P < 0.05). Other live performance traits and carcass characteristics were similar across treatments. Trial 2 evaluated effects of crude glycerin on growth performance and diet digestibility in heifers fed high forage growing diets. Treatments consisted of 0, 4, or 8% crude glycerin added to growing diets containing corn silage (60% of DM) and wet corn gluten feed. Apparent total tract digestibilities were calculated from total fecal collections. Adding glycerin linearly increased (P = 0.01) feed efficiency over the entire feeding period, and linearly decreased (P = 0.02) DMI for a portion of the feeding period. No other effects of glycerin on animal growth performance were observed. Digestibility measurements indicated that glycerin decreased DM, OM, and NDF intakes linearly (P < 0.01), but did not affect fecal outputs of DM, OM, or NDF. Apparent total tract digestibilities of DM, OM, and NDF therefore decreased linearly (P < 0.01) with increasing levels of glycerin. The third trial involved several experiments, which were conducted to determine if glycerol could be used as a solvent in processes designed to facilitate non-enzymatic browning of protein meals. Results indicated that glycerol may serve as a more suitable solvent for browning processes than water because its chemical and physical properties may enhance browning processes, increase process efficiency, and yield products with superior resistance to microbial degradation.

Doctor of Philosophy / Department of Animal Sciences and Industry / James S. Drouillard / Four studies evaluated effects of dry distillers grains with solubles (DDGS) containing high S concentrations on feedlot performance, ruminal fermentation, and diet digestibility by finishing cattle. Trial 1 used finishing steers fed diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC), and containing 30% DDGS (DM) with 0.42% S (0.42S) or 0.65% S (0.65S). No interaction (P ≥ 0.15) between dietary S and grain processing occurred, but feeding 0.65S decreased DMI (P < 0.001) and ADG (P = 0.006) by 8.9% and 12.9%, respectively, whereas G:F was unaffected by S concentration (P = 0.25). Steers fed 0.65S had 4.3% lighter HCW (P = 0.006), lower KPH (P = 0.009), and lower yield grades (P = 0.04) than steers fed 0.42S. Concentration of H2S was inversely related (P ≤ 0.01) to ADG (r = -0.58) and DMI (r = -0.67) in cattle fed SFC, and DMI (r = -0.40) in cattle fed DRC. Trial 2 used the same treatments as in the first stud, and investigated ruminal fermentation characteristics and diet digestibility by feedlot cattle. Feeding 0.65S increased ruminal pH (P < 0.05), but decreased total VFA concentrations (P = 0.05). Steers fed 0.65S had greater ruminal NH3 concentrations (P < 0.01) than steers fed 0.42S. The magnitudes of these effects were greater in steers fed DRC than in steers fed SFC (interaction, P < 0.01). Feeding 0.65S yielded greater apparent total tract digestibilities of DM (P = 0.04) and ether extract (P = 0.03). The 3rd study evaluated effects of in vitro S titration (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6% of DM) in substrates based on ground corn and DDGS (GC-DDGS) or ground corn with urea and soybean meal (GC-SBM). Concentrations of NH3, total VFA, IVDMD, in vitro gas production, and gas composition were unaffected by S (P > 0.05) or by the S × substrate interaction (P > 0.05). Study 4 evaluated cattle feedlot performance when exposed to DDGS containing high S levels, either continuously or intermittently. Treatments were chronic high S (CHS; 0.60% DM), chronic intermediate S (CIS; 0.50% DM), and sporadic intermediate S (SIS; oscillating from 0.40 or 0.60% S DM basis). Steers fed CHS had 11.2 and 6.1% less (P < 0.05) DMI than steers fed CIS and SIS, respectively, but there were no treatment effects on ADG, G:F, or carcass characteristics (P > 0.10). These studies suggest that changes in cattle performance and digestibility associated with high S are primarily attributable to decreased DMI, but infrequent exposure to high levels is no more harmful than continuous exposure.

Call number: LD2668 .T4 1979 T47 / Master of Science