Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Steven S. Dritz / Vaccination against porcine circovirus type 2 (PCV2) has become a standard practice to improve pig mortality and growth rate in PCV2-affected herds. Unfortunately, there has been little field-based research evaluating factors which affect circovirus vaccination. The focus of this research was on potential vaccination-affecting factors such as age, dosing strategy, pig genetic makeup, and interaction with other vaccines. A total of 6,275 pigs were used to determine factors which affect circovirus vaccination and the effects of vaccination on average daily gain (ADG), immune responses, and viral circulation under field conditions. In the first study evaluating circovirus vaccination effects on PCV2 antibody titer, regardless of age and dose administration protocol, pigs vaccinated with a 2-dose circovirus vaccine had increased (P ≤ 0.008) antibody titers compared with non-vaccinates. In a second study, dosing strategy failed (P = 0.31) to affect antibody titers. However, product and time after vaccination did affect (P = 0.005) antibody titers. In another 130-d study across the nursery and finishing phases, pigs vaccinated with a 2-dose circovirus vaccine had decreased (P < 0.001) serum PCV2 viral load compared with non-vaccinates and ADG of vaccinates was better than non-vaccinates. However, the effect was more pronounced (vaccination-by-genetic interaction, P ≤ 0.05) in Duroc-based compared to Pietrain-based pigs. In a study limited to the nursery phase, vaccination for PCV2 and Mycoplasma hyopneumoniae independently reduced ADG and consumption, but the effect was product-dependent. In a 155-d study across the nursery and finishing phases, vaccination with a 2-dose, 2-vaccine program for PCV2 and Mycoplasma hyopneumoniae decreased (P < 0.001) nursery ADG but tended to increase (P = 0.06) finishing ADG compared to a 1-dose, 2-vaccine program, with no difference (P = 0.66) observed between final pig weights. Finally, circovirus vaccination affected PCV2-circulation in high-health research herds but not in a commercial herd where PCV2 DNA was detected in the environment. These results indicate that finishing performance was improved by a 2-dose circovirus vaccine; however, nursery performance was negatively affected by the same product. Circovirus vaccination responses of growth, viral load, and antibody titer were affected by pig genetic makeup, product, and PCV2-exposure status.

A colonização por micro-organismos patogênicos em creches de suínos é um fator importante na disseminação de doenças e surtos no rebanho. O controle desses patógenos se dá principalmente por medidas de biosseguridade, como a prática da limpeza, desinfecção e vazio sanitário das instalações. O presente estudo avaliou a carga bacteriana após o processo de limpeza e desinfecção, durante o período de 3 dias de vazio sanitário, em duas creches de suínos, pelo uso de placas de contato com meio seletivo para coliformes totais. As contagens bacterianas foram analisadas considerando três fatores (água, detergente e desinfetante) em dois níveis para cada (água: fria/quente, detergente e desinfetante: presença/ausência). Foram usadas 4 baias em cada tratamento, 4 pontos de cada baia e cada ponto foi amostrado em triplicata. Foi feita a média de crescimento bacteriano das 3 placas e pontuada em escala de 5 escores. Após limpeza e desinfecção, no primeiro dia de vazio sanitário, houve efeito da interação da água com o detergente (P<0,05), em que o uso do detergente aumentou a chance de diminuir a contaminação quando usado com água quente, mas não com água fria. Na ausência de detergente, a água fria foi mais eficaz em reduzir a contaminação do que a água quente. Houve, também, efeito da interação do detergente com o desinfetante (P<0,05), em que a presença de ambos foi mais eficaz em reduzir a contaminação do que na sua ausência ou quando apenas um dos dois foi utilizado. No terceiro dia, foi verificado que a ausência de desinfetante diminuiu a chance de reduzir a contaminação (P < 0,0001) em comparação com o uso de detergente. A água quente não representou ganho adicional quando comparada a água fria. As evidências aqui observadas reiteram a importância da lavagem, desinfecção e vazio sanitário na redução da carga bacteriana em creche de suínos. A metodologia usada no presente trabalho pode servir como um sistema simples de monitoria dos processos de lavagem e desinfecção de instalações usadas para criação de suínos. / The colonization by pathogenic microorganisms in nursery pig units is an important factor in the spread and outbreaks of diseases in the herds. Pathogens are mainly controlled by biosecurity measures, such as cleaning, disinfection and downtime on facilities. The present study evaluated the bacterial load after the cleaning and disinfection process, during the three days of vacancy, in two pig nurseries, by the use of contact plates selective for enterobacteria. Data were analyzed considering three factors (water, detergent and disinfectant) in two levels (water: cold / hot, detergent and disinfectant: presence / absence). Were used 4 pen for each treatment, and 3 plates for 4 points of the pen. A mean of the 3 bacterial growths was calculated and scored on a 5 point scale. After cleaning and disinfection, there was no detergent - water effect (P <0.05) with cold water. In the absence of detergent, cold water was more effective in reducing contamination than hot water. There was also an effect of the interaction of detergent and disinfectant (P <0.05), where a presence of both was more effective in reducing contamination than in its absence or when only one was used. On the third day, it was found that the absence of disinfectant decreased a chance of reducing contamination (P <0.0001) when compared with the use of detergent. Addition of detergent decreased the chance of contamination when combined with disinfectant, as detergent helps in removing dirt and exposes bacteria which were protected by organic matter and biofilms. The use of hot water did not how advantage when compared with cold water. As there was a fall on contamination between the 1st and 3rd day, the time of action of the disinfectant must be considered to calculate the time of vacancy to permit the action on surviving microorganisms. The results of the present work reinforce the importance of cleaning, disinfection and downtime to reduce bacterial load in swine nurseries. The methodology used in this work may serve as a practical system for monitoring cleaning and disinfection of pig facilities.

A colonização por micro-organismos patogênicos em creches de suínos é um fator importante na disseminação de doenças e surtos no rebanho. O controle desses patógenos se dá principalmente por medidas de biosseguridade, como a prática da limpeza, desinfecção e vazio sanitário das instalações. O presente estudo avaliou a carga bacteriana após o processo de limpeza e desinfecção, durante o período de 3 dias de vazio sanitário, em duas creches de suínos, pelo uso de placas de contato com meio seletivo para coliformes totais. As contagens bacterianas foram analisadas considerando três fatores (água, detergente e desinfetante) em dois níveis para cada (água: fria/quente, detergente e desinfetante: presença/ausência). Foram usadas 4 baias em cada tratamento, 4 pontos de cada baia e cada ponto foi amostrado em triplicata. Foi feita a média de crescimento bacteriano das 3 placas e pontuada em escala de 5 escores. Após limpeza e desinfecção, no primeiro dia de vazio sanitário, houve efeito da interação da água com o detergente (P<0,05), em que o uso do detergente aumentou a chance de diminuir a contaminação quando usado com água quente, mas não com água fria. Na ausência de detergente, a água fria foi mais eficaz em reduzir a contaminação do que a água quente. Houve, também, efeito da interação do detergente com o desinfetante (P<0,05), em que a presença de ambos foi mais eficaz em reduzir a contaminação do que na sua ausência ou quando apenas um dos dois foi utilizado. No terceiro dia, foi verificado que a ausência de desinfetante diminuiu a chance de reduzir a contaminação (P < 0,0001) em comparação com o uso de detergente. A água quente não representou ganho adicional quando comparada a água fria. As evidências aqui observadas reiteram a importância da lavagem, desinfecção e vazio sanitário na redução da carga bacteriana em creche de suínos. A metodologia usada no presente trabalho pode servir como um sistema simples de monitoria dos processos de lavagem e desinfecção de instalações usadas para criação de suínos. / The colonization by pathogenic microorganisms in nursery pig units is an important factor in the spread and outbreaks of diseases in the herds. Pathogens are mainly controlled by biosecurity measures, such as cleaning, disinfection and downtime on facilities. The present study evaluated the bacterial load after the cleaning and disinfection process, during the three days of vacancy, in two pig nurseries, by the use of contact plates selective for enterobacteria. Data were analyzed considering three factors (water, detergent and disinfectant) in two levels (water: cold / hot, detergent and disinfectant: presence / absence). Were used 4 pen for each treatment, and 3 plates for 4 points of the pen. A mean of the 3 bacterial growths was calculated and scored on a 5 point scale. After cleaning and disinfection, there was no detergent - water effect (P <0.05) with cold water. In the absence of detergent, cold water was more effective in reducing contamination than hot water. There was also an effect of the interaction of detergent and disinfectant (P <0.05), where a presence of both was more effective in reducing contamination than in its absence or when only one was used. On the third day, it was found that the absence of disinfectant decreased a chance of reducing contamination (P <0.0001) when compared with the use of detergent. Addition of detergent decreased the chance of contamination when combined with disinfectant, as detergent helps in removing dirt and exposes bacteria which were protected by organic matter and biofilms. The use of hot water did not how advantage when compared with cold water. As there was a fall on contamination between the 1st and 3rd day, the time of action of the disinfectant must be considered to calculate the time of vacancy to permit the action on surviving microorganisms. The results of the present work reinforce the importance of cleaning, disinfection and downtime to reduce bacterial load in swine nurseries. The methodology used in this work may serve as a practical system for monitoring cleaning and disinfection of pig facilities.

A colonização por micro-organismos patogênicos em creches de suínos é um fator importante na disseminação de doenças e surtos no rebanho. O controle desses patógenos se dá principalmente por medidas de biosseguridade, como a prática da limpeza, desinfecção e vazio sanitário das instalações. O presente estudo avaliou a carga bacteriana após o processo de limpeza e desinfecção, durante o período de 3 dias de vazio sanitário, em duas creches de suínos, pelo uso de placas de contato com meio seletivo para coliformes totais. As contagens bacterianas foram analisadas considerando três fatores (água, detergente e desinfetante) em dois níveis para cada (água: fria/quente, detergente e desinfetante: presença/ausência). Foram usadas 4 baias em cada tratamento, 4 pontos de cada baia e cada ponto foi amostrado em triplicata. Foi feita a média de crescimento bacteriano das 3 placas e pontuada em escala de 5 escores. Após limpeza e desinfecção, no primeiro dia de vazio sanitário, houve efeito da interação da água com o detergente (P<0,05), em que o uso do detergente aumentou a chance de diminuir a contaminação quando usado com água quente, mas não com água fria. Na ausência de detergente, a água fria foi mais eficaz em reduzir a contaminação do que a água quente. Houve, também, efeito da interação do detergente com o desinfetante (P<0,05), em que a presença de ambos foi mais eficaz em reduzir a contaminação do que na sua ausência ou quando apenas um dos dois foi utilizado. No terceiro dia, foi verificado que a ausência de desinfetante diminuiu a chance de reduzir a contaminação (P < 0,0001) em comparação com o uso de detergente. A água quente não representou ganho adicional quando comparada a água fria. As evidências aqui observadas reiteram a importância da lavagem, desinfecção e vazio sanitário na redução da carga bacteriana em creche de suínos. A metodologia usada no presente trabalho pode servir como um sistema simples de monitoria dos processos de lavagem e desinfecção de instalações usadas para criação de suínos. / The colonization by pathogenic microorganisms in nursery pig units is an important factor in the spread and outbreaks of diseases in the herds. Pathogens are mainly controlled by biosecurity measures, such as cleaning, disinfection and downtime on facilities. The present study evaluated the bacterial load after the cleaning and disinfection process, during the three days of vacancy, in two pig nurseries, by the use of contact plates selective for enterobacteria. Data were analyzed considering three factors (water, detergent and disinfectant) in two levels (water: cold / hot, detergent and disinfectant: presence / absence). Were used 4 pen for each treatment, and 3 plates for 4 points of the pen. A mean of the 3 bacterial growths was calculated and scored on a 5 point scale. After cleaning and disinfection, there was no detergent - water effect (P <0.05) with cold water. In the absence of detergent, cold water was more effective in reducing contamination than hot water. There was also an effect of the interaction of detergent and disinfectant (P <0.05), where a presence of both was more effective in reducing contamination than in its absence or when only one was used. On the third day, it was found that the absence of disinfectant decreased a chance of reducing contamination (P <0.0001) when compared with the use of detergent. Addition of detergent decreased the chance of contamination when combined with disinfectant, as detergent helps in removing dirt and exposes bacteria which were protected by organic matter and biofilms. The use of hot water did not how advantage when compared with cold water. As there was a fall on contamination between the 1st and 3rd day, the time of action of the disinfectant must be considered to calculate the time of vacancy to permit the action on surviving microorganisms. The results of the present work reinforce the importance of cleaning, disinfection and downtime to reduce bacterial load in swine nurseries. The methodology used in this work may serve as a practical system for monitoring cleaning and disinfection of pig facilities.

<p>  </p> <p>In commercial settings, piglet weaning and transportation occur concurrently due to the expansive application of multi-site production systems across the United States and the combination of these events can be defined as an early life stressor. Early life stress is known to reduce pig performance, efficiency, and immune resilience contributing to reduced welfare and increased production losses. To combat the deleterious effects of stress on pigs, the essential amino acid tryptophan (Trp) supplemented above current National Research Council (NRC 2012) recommended levels, improves neuroendocrine responses to stress, lowers plasma cortisol and norepinephrine concentrations, and improves hypothalamic-pituitary-adrenal axis recovery time following stress. However, there are discrepancies concerning the Trp requirement for nursery pigs, suggesting the 2012 recommendations for Trp may be inaccurate for optimizing growth performance and health in modern pigs. Three experiments were conducted to determine the effects of supplemented standard ileal digestible Trp above NRC (2012) recommended levels on performance, feed efficiency, immune vigor, and stress tolerance. The objective of experiment 1 was to eliminate or reduce short- and long-term, transport-induced reductions in piglet feed efficiency and growth by supplementing Trp above NRC (2012) recommendations pre-weaning and/or during the nursery phase. An oral gavage of Trp or a control milk carrier was provided to pre-allotted piglets beginning at day 5 of lactation and continuing to weaning. At weaning all pigs were blocked by sex, weaning weight and pre-wean treatment and randomly assigned to transport and post-wean treatments. Pigs were fed in four nursery phases with diets containing 1X or 2X NRC recommended concentrations of SID Trp and a common grower diet fed in 6 phases during the grow-finish period. At market, loin characteristics were measured via ultrasound and carcass data was collected from the packing plant. Pre-weaning Trp supplementation had no effect on pre-weaning growth performance; however, post-wean Trp increased overall body weight and average daily gain in nursery pigs when Trp was supplemented pre-wean. The objective for experiment 2 was to mitigate the adverse effects of early life transport stress on subsequent immune challenges by providing supplemental Trp during the nursery period. At weaning, pigs were transported for 8 hours and assigned to treatments of vaccine-induced immune challenge and dietary treatment. Pigs were fed standard nursery diets, in four phases, over 35 days with pigs receiving 1X or 2X the NRC (2012) recommended Trp concentration. Half the pigs on each dietary treatment were subjected to a 3-wk vaccine challenge consisting of circovirus, mycoplasma, and influenza vaccines administered in wk 2, 3, and 4 post-wean, respectively. At market, loin characteristics were measured via ultrasound and carcass data was collected.  At the culmination of the nursery period, unchallenged pigs supplemented with Trp were heavier compared to control pigs. This resulted from an overall improvement in average daily gain for 2X Trp fed pigs. However, increasing Trp did not affect market weight, loin eye area, or lean percent in market pigs, although 2X Trp increased back fat. The objective of experiment 3 was to determine what ratio of SID tryptophan, relative to lysine, maximizes growth performance and feed efficiency in weaned pigs during the nursery period. Pigs were blocked by sex and weaning weight and randomly allotted to one of five dietary treatments with Trp increasing stepwise by 0.33%-units, respectively. Pigs were fed standard nursery diets, in four phases, over 35 days with pigs receiving 1X, 1.33X, 1.66X, 2X, or 2.33X the NRC (2012) recommended Trp concentration.  Overall, there were no differences in performance or efficiency across dietary treatments during a 35-day nursery period in unstressed healthy pigs.  In conclusion, increasing Trp in swine diets prior to and/or following stress events can mitigate stress-related perturbations in performance and efficiency.      </p>