Four studies were conducted to evaluate the potential for post-extraction algal residue (PEAR) to be incorporated as a protein source in the grazing sector of the beef cattle industry. In Experiment 1, blends of PEAR and conventional protein supplements (dried distillers’ grains, DDG; cottonseed meal, CSM) were offered to steers consuming Bermudagrass to evaluate palatability of PEAR. Supplement completion, time required for consumption, and amount of supplement consumed were recorded. In Experiment 2, isonitrogenous amounts of PEAR and CSM (100 mg N/kg BW) were supplemented to steers consuming low-quality forage to compare effects on nutrient utilization. Experiment 3 evaluated the optimal inclusion rate of PEAR to steers consuming low-quality forage. Treatments included no supplemental protein, 3 levels of PEAR (50, 100, and 150 mg N/kg BW) and 1 level of CSM (100 mg N/kg BW). In Experiment 4, the effects of upstream operations on the nutritive value of PEAR were quantified. Observations indicate PEAR may be blended with existing protein sources in the beef industry without negatively affecting palatability, but there may be palatability concerns when PEAR is offered alone. Provision of 100 mg N/kg BW of PEAR or CSM stimulated forage intake (P ≤ 0.05) and increased N retention (P = 0.02) relative to unsupplemented animals. Imbalances in mineral intakes (Ca:P ratio of 8:1) were observed when PEAR was supplemented, but not CSM. Total digestible OM intake (TDOMI) responded quadratically (P = 0.01) to increasing provision of PEAR with maximization occurring when PEAR was provided at 100 mg N/kg BW. There was not a difference in TDOMI (P = 0.13) at isonitrogenous levels of PEAR and CSM, indicating forage utilization was stimulated to a similar extent. Excess mineral levels and imbalances in PEAR were largely a result of cultivation, harvesting, and extraction procedures which could be controlled. Thus, there is potential to alter production streams to optimize oil yield and co-product value. Overall, our results indicate PEAR can be incorporated as a protein source in the beef cattle industry, thus increasing economic viability of biofuel production from algal biomass.

Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Daniel U. Thomson / Beta-adrenergic agonists (βAA) are administered during the final weeks of the beef production system to improve efficiency and increase meat yield. Welfare concerns linked to the administration of βAA have garnered significant attention in recent years due to anecdotal reports of increased mortality during βAA feeding periods and cattle without obvious disease or injury having difficulty walking at abattoirs being overrepresented in cattle fed βAA. Thomson et al. (2015) reported 2 events where cattle were distressed, became non-responsive to handling, sloughed hoof walls and were euthanized while in lairage at the abattoir. Consistent blood abnormalities in euthanized cattle included elevated blood lactate (25.6 mmol/L; ref. range: < 4-5) and creatine kinase (CK; 6,890 U/L, ref. range: 159- 332). Although no causal relationship had been established, dialogues among groups of packers, animal scientists, and welfare experts implicating the βAA zilpaterol hydrochloride (ZIL; Zilmax®, Merck Animal Health, Desoto, KS) as one possible etiology resulted in a major beef packer announcing plans to stop accepting cattle fed ZIL. Consequently, Merck announced a self-imposed suspension of ZIL sales in U.S. and Canadian markets until further research could be conducted to investigate the manner. Utilization of technologies such as βAA are imperative to meeting the demands of a growing world population and verdicts regarding such technologies, including their impact on animal welfare, should be based on scientific merit. The first objective of this research was to evaluate the effect of shade on performance and animal well-being in cattle fed ZIL. The second objective was to characterize the clinical description and hematological profile of fatigued cattle presented to abattoirs. The third objective was to evaluate the effects of handling intensity during shipment for slaughter in cattle fed a βAA. The fourth objective was to evaluate the effects of βAA administration on performance and physiological response to different handling intensities during shipping for slaughter. Shade provision reduced open-mouth breathing and increased dry matter intake and dressing percentage. Fatigued cattle observed at abattoirs had increased respiratory rates and muscle tremors, although blood parameters were relatively normal compared to their cohorts. Metabolic acidosis, a precursor for Fatigued Cattle Syndrome, was observed in cattle exposed to aggressive handling regardless of βAA status. This research confirms the improved growth performance of cattle fed βAA and highlights the improvement of animal welfare through shade provision and low-stress handling in heavy-weight feedlot cattle.

Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Robert L. Larson / Bradley J. White / Utilization of data analytics allows for rapid and real-time decision making in the food animal production industry. The objective of my research was to implement and utilize different data analytic strategies in multiple sectors of the beef cattle industry in order to determine management, health, and performance strategies. A retrospective analysis using reproductive and genomic records demonstrated that a bull will sire a larger number of calves in a multiple sire-pasture compared to other bulls in the same pasture. A further study was performed to determine if behavior differences existed among bulls in a multiple-sire pasture, and the ability of accelerometers to predict breeding behaviors. Machine learning techniques used classifiers on accelerometer data to predict behavior events lying, standing, walking, and mounting. The classifiers were able to accurately predict lying and standing, but walking and mounting resulted in a lower predictable accuracy due to the extremely low prevalence of these behaviors. Finally, a new form of meta-analysis to the veterinary literature, a mixed treatment comparison, was able to accurately identify differences in metaphylactic antimicrobials on outcomes of bovine respiratory disease morbidity, mortality, and retreatment morbidity. The meta-analysis was not successful in determining the effects of metaphylactic antimicrobials on performance outcomes.

Master of Science / Department of Clinical Sciences / Daniel U. Thomson / Acute Interstitial Pneumonia (AIP) is a costly issue that affects feedlot cattle, especially during hot and dry summers. Research has yet to elucidate the exact etiology of AIP; therefore this study was conducted to determine possible factors that contribute to AIP in feedlot cattle. During the summer of 2011 in a 55,000 head feedyard in southwest Kansas, animals exhibiting clinical signs of AIP were selected for ante-mortem examination and data collection. The animal population within the feedlot consisted of 75% heifers and 25% steers. Approximately 50% of the animal population was black hided animals. Ante-mortem data consisted of rumen gas cap measurement for NH3 and H2S, rumen pH, serum chemistry, rectal temperature, and body weight. Post-mortem cases with and without ante-mortem evaluations were also selected for an additional examination. Postmortem examination included similar data as ante-mortem examination with addition of visual and histological examination of lung tissue. There were 31 ante-mortem cases of clinical AIP with the following observations (mean ± SD): rectal temperature 105.3 ± 0.7 °F, weight 1098 ± 123 lbs., H2S 136 ± 133.3 ppm, and rumen pH 6.4 ± 0.5. Twenty-five healthy cohorts were selected from identical pens to serve as controls. Observations from control animals were: rectal temperature 103.7 ± 1.1 °F, weight 1113 ± 133.3lbs, H2S 269.8 ± 311.6 ppm and rumen pH 6.2 ± 0.6. A total of 61 post-mortem cases with a preliminary diagnosis of AIP were analyzed and displayed the following values: H2S 1279.7 ± 1569 ppm, and rumen pH 6.3 ± 0.36. Fifty-three of these postmortem cases had diffuse, focal and /or patchy AIP confirmed by histology.

Orientador: Eunice Oba / Banca: Sony Dimas Bicudo / Banca: Paulo Henrique Franceschini / Banca: José Bento Steman Ferraz / Banca: Simone Eliza Facioni Guimarães / Resumo: Objetivo deste trabalho foi verificar se mães classificadas como superprecoces (M1) e precoces (M2) produzem touros mais precoces que as fêmeas classificadas como normais (M3). Foram utilizados 21.186 animais com média de 21,29±1,77 meses, avaliados em exame andrológico entre os anos de 1999 e 2008, onde 2.019; 6.059 e 13.108 eram filhos de fêmeas M1, M2 e M3, respectivamente. As características andrológicas integrantes da avaliação física (motilidade progressiva retilínea - MOT, vigor espermático - VIG), morfologia do sêmen (defeitos espermáticos maiores - DM, menores - DME e totais - DT) e do exame clínico dos testículos (perímetro escrotal - PE, volume testicular - VT e formato testicular - FT) bem como do PE aos 18 meses de idade (PE18) e medidas ponderais de peso ao nascimento (PESNAS), ao desmame (PES205) e ao sobreano (PES550) foram estudados. Ao exame andrológico os animais foram classificados como aptos à reprodução, aptos à reprodução em regime de monta natural, inaptos à reprodução e descartados. Para comparar as médias encontradas para cada categoria de mãe dentro das classes andrológicas individualmente, foi utilizado o teste qui-quadrado com probabilidade de 5% de erro, considerando o efeito do ano, mês de nascimento e fazenda. Estimativas de herdabilidade e correlações genéticas do PE18, PE, VT, MOT, VIG, DM, DME e DT foram avaliadas para cada categoria de mãe. Foram registradas 67,26; 67,22 e 64,16% de tourinhos considerados aptos à reprodução, e 19,71; 19,46 e 21,90% (p<0,05%) inaptos à reprodução, respectivamente para as classes de mães M1, M2 e M3. Não foram observadas diferenças para os animais aptos à reprodução em regime de monta natural entre as três categorias de mães (médias de 8,87; 9,31 e 9,19%, respectivamente). Para os animais descartados observou-se apenas diferença entre a categoria... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this work was to check if cows classified as super precocious (M1) and precocious (M2) might produce more precocious bulls than the ones from females classified as normal (M3). The animals from this experiment were assessed between the years 1999 and 2008, and they were all the same age average (21.29 months) totalizing 21,186 bulls. All animals went under breeding soundness examination, being 2,019; 6,059 and 13,108; M1's, M2's and M3's offspring, respectively. It was assessed the following characteristics: physical evaluation (progressive motility - PM, sperm vigor - SV), semen morphology (minor defects - MID, major defects - MAD, and total defects - TD), clinical assessment of the testicles (scrotal circumference - SC, testicle volume - TV and testicle shape - TS), scrotal circumference at the age of 18 months (SC18) and bodyweight at birth (BWB), bodyweight at weaning (BWW) and bodyweight at yearling (BWY). After breeding soundness examination animals were classified as able to reproduce, able to reproduce in natural breeding situation, unable to reproduce, and discharged. In order to evaluate the averages found for each category of cow within each andrological class, it was performed the qui-square with a 5% error probability, taking into account the effects year and month of birth, together with the farm origin. Heritability estimation and genetic correlation between SC18, SC, TV, MOT, VIG, MAD, MID and TD were assessed for each cow category. For cows M1, M2 and M3, respectively, were registered 67.26; 67.22 and 64.16% bulls that were able to reproduce, and 19.71; 19.46 and 21.90% (p<0.05%) unable to reproduce. It was not found any difference between M1, M2 and M3 for animals that were able to reproduce in natural mounting scheme (averages of 8.87; 9.31 and 9.19 %, respectively). Discharged animals only showed different values for... (Complete abstract click electronic access below) / Doutor

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Thesis (M.Sc. (Agricultural economics)) --University of Limpopo, 2011 / The cattle (especially beef) industry in Botswana has traditionally played an important role in the country’s economy, with significant contributions to Gross Domestic Product (GDP), exports, and employment, as well as playing an important role in social and cultural spheres. Agriculture contributes about 2.3 % of GDP, out of which 70% - 80% is attributable to cattle production. By 2004, beef exports amounted to P284m, approximately 1.7% of total exports of P16.2 billion. In recent years, however, there have been signs of decline and stagnation, especially in the beef export subsector, with adverse implications for the viability of cattle farming in the country, and more generally for rural livelihoods. Botswana’s beef subsector has not fulfilled its potential as a contributor to economic growth and development, especially in the rural areas. The BMC has never been able to meet its quota of 19 000 tonnes of beef to the European Union (EU), despite being cushioned by the Continuo agreement against price competition from more efficient beef producers like Brazil. With the above background, the study was undertaken to examine the supply response of beef farmers in Botswana to various economic (e.g. prices) and non-economic [e.g. rainfall, technology and inventory (cattle population)] factors. This study used historical data on Botswana’s beef subsector for the period 1993 to 2005, and Nerlove’s partial adjustment model was used for the empirical analysis of the data. The results of the study revealed that Botswana beef farmers respond positively to price incentives and time trend (proxy for technology), and negatively to all other variables. Elasticities of supply showed that cattle supply is elastic with respect to variations in producer price and almost unit elastic to changes in cattle inventory. However, the response to shocks in other variables included in the model was inelastic. Short run price elasticity of supply is 1.511 whereas long run price elasticity is 10.57, a clear sign that pricing can be employed as a strategy to enhance beef production in Botswana. The speed of adjustment however, was relatively very low at 14% per period. This slow adjustment perhaps tells us that Botswana farmers, who are predominantly subsistence farmers, may not be having enough capacity (in terms of resources and technology) to immediately increase production when economic environment improves in their favour. Based on the results it is recommended that price increase be adopted as a strategy for improving cattle supply. Extension services need to be strengthened with a view of promoting cattle farming as a commercial activity. Current technology of using communal grazing and indigenous breeds need to be improved. It is also recommended that studies be conducted to determine the suitability of technology that is at the disposal of the farmers. Lastly Botswana government needs to come up with a strategy by which farmers can change from their attitude of oxen production to weaner production.