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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.
41

Maternal, Neonatal and Feeding Type Factors Associated with Severity of Necrotizing Enterocolitis

Miner, Cheryl Ann 02 November 2011 (has links)
Objective: To identify statistical associations with necrotizing enterocolitis (NEC) severity as dichotomized into cases with Bell stage II and III disease. Study Design: We conducted a retrospective study using eight consecutive years of data from a multihospital healthcare system analyzed NEC severity (Bell stage II vs. III). Results: We identified 220 neonates with stage ≥ II who had 225 separate episodes of NEC (157 stage II and 68 stage III). Those with stage III were born at earlier gestational age (P<0.0001) and lower birth weight (P<0.0001). Diagnosis of NEC occurred on about the same day of life in stage II and stage III cases. Those who developed stage III had significantly higher C-reactive protein (P<0.0001), I/T ratio (P= 0.0005), mean platelet volume (MPV) (P= 0.0001) and lower pH (P<0.0001) and platelet counts (P<0.0001). Transfusions were more common to those who progressed to stage III (P<0.0001). Regression analysis indicated higher odds of stage III in relationship to the volume of RBC transfusions (OR 2.41, {CI 1.85 to 3.11}, P<0.0001) and pasteurized human milk (PHM) (OR 1.32, {CI 1.07 to 1.62}, P = 0.0089). In contrast, feeding early mother's own milk (colostrum) for five days reduced the odds for stage III (OR 0.802, {CI 0.67 to 0.96}, P=0.0170). Those with small bowel resection were less likely to have received mother's own milk before NEC (OR 0.94, {CI 0.89 to 0.99}, P = 0.019) and factors predicting death from NEC were a low pH (OR 2.21, {CI 1.27 to 3.85}, P = 0.0005) and less colostrum (OR 0.96, {CI 0.94 to 0.99}, P = 0.003). Conclusions: RBC transfusions and PHM increased the odds for stage III NEC, whereas early mother's own milk five days reduced the odds. Mother's own milk with PHM decreased the risk for small bowl resection and early mother's milk decreased the odds for mortality from NEC. Future research and prospective randomized controlled studies are needed to quantify any reduction in NEC severity on the basis of decreasing RBC transfusions and increasing early mother's own milk or colostrum.
42

The relationship of prepartum body condition score to postpartum colostrum quality and milk yield and composition in polypay sheep

Al-Sabbagh, Tariq Ashour 21 June 1994 (has links)
Graduation date: 1995
43

Effects of Maternal Nutrition Manipulation on Mares and Their Foals

Winsco, Kelly N 03 October 2013 (has links)
Previous research documented the fetus is sensitive to nutrition of the dam, but this has not been thoroughly investigated in horses. Objectives of the current studies were to determine effect of manipulation of maternal nutrition during the last third of pregnancy on mare performance, intake, hormones, foaling parameters, colostrum, and foal passive transfer of immunity and growth, and effects of supplemental arginine. Plane of nutrition influenced mare performance, and DMI was influenced by time with the first trial finding all mares consumed less in the 10th month of pregnancy compared to the 11th month, and the second trial finding all mares consumed less during the 11th month. Additionally, the second study determined arginine supplementation has no detrimental effects on DMI. Both studies indicated the dual marker system was sufficient at estimating DMI. Neither trial found an influence of treatment on foaling parameters or physical measurements obtained following parturition, and the second study determined arginine supplementation also did not affect foaling or measurements. The first study determined maternal nutrition did not affect foal growth or ADG. When colostrum quality was evaluated, the first study determined mares consuming only hay had increased specific gravity and Brix% indicating higher quality. This was confirmed by IgG analysis finding a tendency for increased IgG concentration. However, colostrum volume was not affected by nutrition, nor was total g IgG. The second study found contrasting results with greater specific gravity in mares on a high plane of nutrition, and a tendency for moderate plane of nutrition mares to have greater volume. Additionally, the second study determined that arginine supplementation does not influence colostrum volume or quality (measured by specific gravity or Brix %). In the first trial, maternal diets affected glucose and insulin AUC in mares, which altered insulin dynamics in the resulting foals. Foal insulin AUC and peak insulin concentration were greater in foals from mares supplemented with concentrate compared to foals from mares fed hay alone. These studies have provided a wealth of information to help elucidate the impact of maternal nutrition in late gestation on mares and their foals.
44

Vliv kvality mleziva na růst a zdravotní stav telat

RAJTROVÁ, Aneta January 2018 (has links)
The thesis summarizes the importance of the quality of colostrum, its composition and impact on the growth and state of health of calves. Colostrum includes important substances necessary for the health of a calf. The value of overall protein in which the amount of immunoglobulins is reflected is a key indicator. It is important for the health of the calf that it receives sufficient amount of quality colostrum in time, gaining immunoglobulins necessary for the first weeks of life. Significant aspects include the quality of colostrum that we provide a calf with, the amount of colostrum consumed, technology, consistency and personnel responsibility, which reflect retrospectively during the inspection of colostrum nutrition of calves that can be carried out by several methods mentioned further. These aspects influence the state of health of calves, growth and many more indicators in the production that follows. In the work, I concentrated on these very aspects, the extent to which they interact as well as on the state of health of calves. The data that I was provided with by Ing. Barbora Šitnerová (principal livestock specialist of Agraspol Předmíř a.s.) was processed into tables and graphs from which statistically important results were learnt.
45

Colostro e leite de éguas: análise mirobiológica e contagem de células somáticas / Colostrum and milk of mares: composition, microbiological analysis and somatic cell count

Bernardineli, Ana Paula Bertoni [UNESP] 27 October 2014 (has links) (PDF)
Made available in DSpace on 2015-10-06T13:02:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-27. Added 1 bitstream(s) on 2015-10-06T13:19:31Z : No. of bitstreams: 1 000849099_20161107.pdf: 186790 bytes, checksum: cb1fc4c101eda7237727df1b682b20b5 (MD5) Bitstreams deleted on 2016-11-07T12:49:31Z: 000849099_20161107.pdf,. Added 1 bitstream(s) on 2016-11-07T12:50:06Z : No. of bitstreams: 1 000849099.pdf: 526018 bytes, checksum: db023165c65c98dd3ef83f241bd3cc8d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Diante da importância do colostro e leite de égua na alimentação e aquisição de imunidade de potros recém nascidos e na sua utilização na dieta humana, o objetivo do estudo foi avaliar a composição, propriedades físico-químicas, perfil microbiológico e contagem de células somáticas (CCS) do colostro e leite de éguas na fase inicial da lactação. As amostras foram coletadas de 36 éguas em sete momentos: M1= momento do parto, M2= 12 horas, M3= 24 horas, M4= 36 horas, M5= 48 horas, M6= onze dias e M7= 15 dias após o parto. Houve queda nos teores de proteína, gordura, sólidos totais e sólidos desengordurados, e aumento dos teores de lactose durante os momentos estudados. Também houve variação nos valores de pH, índice crioscópico e acidez durante os momentos, principalmente entre amostras de colostro e leite de transição. Houve isolamento microbiológico em 5,55% das amostras cultivadas, das quais 28,57% eram Streptococcus não hemolítico, 28,57% Streptococcus α hemolítico, 21,43% Streptococcus equi, 14,29% Micrococcus spp. e 7,14% Bacillus spp. Nenhum animal apresentou mastite clínica. Maiores valores de CCS foram encontrados no M1 e M2, com diminuição significativa no M3, com valores inferiores a 100.000 células somáticas/mL a partir deste momento. Perante os resultados podemos constatar alterações na composição, qualidade físico-química e celularidade durante os 15 primeiros dias de lactação. Onze amostras foram positivas ao California Mastitis Test, sendo observadas no M1 (36,36%), M2 (27,27%), M3 (18,19%), M5 (9,09%) e M7 (9,09%). Bactérias do gênero Streptococcus foram as mais frequentes isoladas. Entretanto, é necessário cautela na utilização de alguns métodos de diagnóstico de mastite, já que não há padronização dos mesmos para a espécie equina / Given the importance of colostrum and milk of the mare on feeding and acquisition of immunity of newborn foals and their use in the human diet, the aim of the study was to evaluate the composition, physicochemical properties, microbiological profile and somatic cell count (SCC) of colostrum and milk of mares in early lactation. Samples were collected from 36 mares at seven moments: M1 = moment of partum, M2 = 12 hours, M3 = 24 hours, M4 = 36 hours, M5 = 48 hours, M6 = 11 days and M7 = 15 days post-partum. It was observed decreased levels of protein, fat, total solids and solids non-fat, and increased levels of lactose during the evaluated moments. There was also variation in pH, cryoscopic index and acidity during the moments, especially between samples of colostrum and transitional milk. The microbiological isolation occurred in 5.55% of the cultured samples, of which, 28.57% was non-hemolytic Streptococcus, 28.57% α-hemolytic Streptococcus, 21.43% Streptococcus equi, 14.29% Micrococcus spp. and 7.14% Bacillus spp. No animals showed clinical mastitis. Higher SCC values were found in M1 and M2, with a significant decrease in M3, with values less than 100,000 somatic cells / mL from this moment. Given these results, changes in the composition, physicochemical quality and cellularity during the first 15 days of lactation were observed. Eleven samples were positive on California Mastitis Test, being observed in M1 (36.36%), M2 (27.27%), M3 (18.19%), M5 (9.09%) and M7 (9.09%). Bacteria of the genera Streptococcus were the most frequently isolated. However, caution is needed in the use of some methods for diagnosis of mastitis, because there is no standardization in the equine species
46

Hemograma e perfil bioquímico de bezerros neonatos da raça Holandesa tratados com ferro suplementar

Franciosi, Camila [UNESP] 31 May 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-31Bitstream added on 2014-06-13T19:30:24Z : No. of bitstreams: 1 franciosi_c_me_jabo.pdf: 5104650 bytes, checksum: 55bf438b23e827337f09f158f9132364 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente estudo teve como objetivos avaliar a influência do tratamento com ferro suplementar no hemograma e no perfil bioquímico de bezerros neonatos da raça Holandesa, estabelecer um protocolo de tratamento com ferro suplementar com intuito de controlar a ocorrência de anemia ferropriva nesses animais e avaliar os componentes da secreção láctea fornecida aos bezerros. Para isso, foram constituídos cinco grupos experimentais, compostos por oito bezerros cada, que foram submetidos à aplicação por via intramuscular de: 5 mL de solução fisiológica estéril (Grupo 1); 5 mL de ferro dextrano 10%, no quinto dia de idade (Grupo 2); 5 mL de ferro dextrano 10%, no quinto e no vigésimo dia de idade (Grupo 3); 5 mL de ferro dextrano 10% no quinto e no trigésimo dia de idade (Grupo 4); 5 mL de ferro dextrano 10% no quinto, no vigésimo e no quadragésimo quinto dia de idade (Grupo 5). Foram coletadas amostras de sangue e de leite logo após o nascimento e aos 5, 10, 20, 30, 60 e 90 dias de idade, para a realização de exames hematológicos, bioquímicos e fracionamento eletroforético das proteínas. Os resultados mostraram que o teor sérico de ferro e de lactoferrina e o eritrograma foram positivamente influenciados pela administração de ferro suplementar, sem, no entanto causar nefrotoxicidade ou hepatoxicidade, sendo o protocolo mais efetivo aquele em que os animais receberam três aplicações de ferro suplementar (Grupo 5). Também foi possível concluir que as concentrações dos componentes da secreção láctea fornecida aos bezerros foram muito maiores no colostro, em comparação com àquelas do leite integral, sugerindo que o leite pode possuir quantidade de nutrientes, principalmente de minerais, menor do que aquela necessária para o neonato / The aim of the present study was to evaluate the influence of supplementary iron treatment in the hemogram and biochemical profile of neonatal Holstein calves, to establish a protocol for treatment with supplementary iron to control the occurrence of iron-deficiency anemia and to evaluate components of the lacteal secretions fed to the calves. In order to evaluate this influence, five experimental groups were formed, comprising eight calves each, that were submitted to intramuscular administration of : 5 mL of sterile saline solution (Group 1); 5 mL of 10% iron dextran in the fifth day of life (Group 2); 5 mL of 10% iron dextran in the fifth and twelfth days of life (Group 3); 5 mL of 10% iron dextran in the fifth and thirtieth days of life (Group 4); 5 mL of 10% iron dextran in the fifth, twelfth and fortieth days of life (Group 5). Blood and milk samples were collected soon after birth/calving and at 5, 10, 20, 30, 60, and 90 days of life, to evaluate the hematology, biochemistry and electrophoretic fractioning of proteins. The results showed that the iron and lactoferrin levels and the eritrogram were positively influenced by the supplementary iron administration, being the three administrations protocol of supplementary iron the most effective (Group 5). It was also possible to conclude that the levels of the lacteal secretions components given to the calves were much higher in the colostrum than in the whole milk, suggesting that the milk might have nutrient concentrations, especially minerals, smaller than the necessary for the neonate
47

Vigor, variação na concentração de metabólitos sanguíneos e avaliação da transferência de imunidade passiva em bezerros leiteiros neonatos / Vigor, variation in blood metabolites concentration and evaluation of passive immunity transfer in newborn dairy calves

Nathália Brito Rocha 18 February 2016 (has links)
O objetivo deste trabalho foi identificar o padrão de vigor e status metabólico através da determinação da frequência dos sinais objetivos e metabólitos sanguíneos após o nascimento, possivelmente associados à transferência de imunidade passiva, além de determinar o melhor horário para o uso do refratômetro de Brix na avaliação da transferência de imunidade passiva em bezerros neonatos após a ingestão de colostro. No primeiro experimento foram utilizados 46 bezerros neonatos de ambos os sexos, nascidos entre setembro de 2013 e julho de 2014. A avaliação do vigor dos animais foi realizada entre 15 e 30 minutos após o nascimento com o auxílio da escala APGAR modificada pela Universidade de Guelph. A colheita de sangue para análise de metabólitos seguiu os horários de 0h (antes da ingestão), 1h, 2h, 4h, 6h, 12h, 24h, 48h contadas a partir da ingestão do colostro. Os parâmetros sanguíneos foram determinados por kit enzimático específico para cada parâmetro em Sistema Automático para Bioquímica. Todos os animais utilizados neste estudo foram oriundos de partos eutócicos e apresentaram, de acordo com a escala APGAR, vigor satisfatório. As concentrações de metabólicos sanguíneos dos neonatos mostraram que o consumo de colostro aumentou a disponibilidade de energia e a concentração de frações proteicas, comumente utilizadas como indicativos da transferência de imunidade passiva. No segundo experimento foram utilizados 47 bezerros neonatos de ambos os sexos, nascidos entre março e julho de 2014. O colostro foi ordenhado após o parto e a qualidade determinada com auxílio do colostrômetro e do refratômetro digital. A colheita do sangue para a análise dos parâmetros sanguíneos seguiu os horários de 0h (antes da ingestão), 1h, 2h, 4h, 6h, 12h, 24h, 48h, 72h, 96 e 120h, contadas a partir da ingestão do colostro. A concentração de proteína total foi determinada por refratômetro de Brix e por kit enzimático em Sistema Automático para Bioquímica. Os demais parâmetros sanguíneos foram determinados por kit enzimático específico para cada parâmetro em Sistema Automático para Bioquímica. A contagem global e diferenciada das células sanguíneas foi realizada nos tempos 0, 12 e 24h após o fornecimento do colostro. O colostro se manteve na faixa de boa qualidade, segundo os critérios de classificação de medidas pelo colostrômetro e refratômetro digital de Brix. O consumo de colostro foi o principal fator de variação dos parâmetros estudados neste trabalho. A avaliação da transferência de imunidade passiva em bezerros recém-nascidos deve ser realizada por volta das 24 horas após a ingestão do colostro, pois neste momento a absorção de macromoléculas colostrais já está encerrada e a PT alcança estabilidade. A partir deste período, não é possível determinar se as frações proteicas avaliadas são de origem colostral ou endógena, o que não garante avaliação segura sobre a transferência de imunidade passiva. / The objective of this study was to identify the vigor and metabolic status through the determination of objective signs and blood metabolites just after birth of dairy calves, possibly associated with the passive immunity transfer. Also, determine the best time after colostrum intake to estimate the passive immunity transfer using a Brix refractometer. The first trial evaluated 46 newborn calves, males and females, born from September 2014 to July 2014. Animals\' vigor evaluations were carried out between 15 and 30 minutes after birth using the APGAR scale modified by the University of Guelph. The blood sample collection for metabolites analysis were done at 0h (before intake), 1h, 2h, 4h, 6h, 12h, 24h, and 48h after colostrum intake. Blood parameters were analyzed by enzymatic kits using an automatic biochemical system. All animals were born from eutocic births and presented, according to the APGAR scale, satisfactory vigor. The newborns metabolites blood concentrations revealed that colostrum intake increased the energy availability and the concentration of protein fractions, commonly used as indicative of passive immunity transfer. For the second trial 47 newborn calves of both sexes, born from March and July 2014, were used. The colostrum was milked after parturition and quality was determined using a colostrometer and digital Brix refractometer. Blood samples were taken from calves at 0h (before intake), 1h, 2h, 4h, 6h, 12h, 24h, 48h, 72h, 120h and 96, after colostrum intake. The total protein (TP) concentration was measured by a Brix refractometer and an enzymatic kit using an automatic biochemical system. Other blood parameters were determined by specific enzyme kit for each parameter in Automatic System for Biochemistry. The global and differential blood cell count were performed at times 0, 12 and 24h after colostrum feeding. Colostrum has remained in the range of good quality according to the criteria of classification measures by colostrometer and digital Brix refractometer. Colostrum intake was the main factor of variation of the studied parameters. The evaluation of the passive transfer of immunity to newborn calves should be performed at about 24 hours after colostrum intake, because at this time, the absorption of colostral macromolecules is already finished and TP reaches stability. From this period, it is not possible to determine whether the assessed protein fractions are from colostrum or endogenous origin, which does not guarantee reliable assessment on the transfer of passive immunity.
48

Caracterização quantitativa e funcional da transferência de anticorpos anti-Dermatophagoides pteronyssinus via placenta e colostro materno. / Quantitative and functional characterization of antibodies anti-Dermatophagoides pteronyssinus transference through placenta and maternal colostrum.

Patricia Macchiaverni 12 August 2008 (has links)
Existem fortes evidências de que a supressão da hipersensibilidade nos recém nascidos pode ser mediada pela transferência de anticorpos maternos, dependendo de sua concentração e especificidade, no entanto carece estudos sobre a eficácia em humanos. Realizamos este estudo a fim de caracterizar qualitativa e quantitativamente a transmissão de anticorpos direcionados ao principal alérgeno da poeira domiciliar (Der p) via placenta e colostro materno, assim como investigar o efeito da sensibilização materna ao Der p na transferência passiva destes anticorpos. Para tais objetivos, analisamos amostras de sangue materno, cordão umbilical e colostro de puérperas sensibilizadas. Demonstramos pela primeira vez que S-IgA anti-Der p pode ser transferida ao lactente em concentrações bastante variáveis e com alto índice de avidez, independente da sensibilização materna ao mesmo ácaro. Demonstramos também que o nível de IgG específica ao Der p é mais elevado em recém nascidos de mães sensibilizadas quando comparado aos de mães controle não sensibilizadas. Já a avidez específica da IgG anti-Der p foi muito semelhante entre as amostras pareadas de cordão umbilical e soro materno, assim como em amostras do grupo estudo e grupo controle. / It is known that the incidence of allergic disease has been rising very fast in the last decade and nowadays affects thousands of children worldwide. For this reason, it is of great interest that efficient strategies of prevention of atopy should be applied in the first years of life or even before birth. The are strong evidences that the suppression of hypersensitivity in newborn can be mediated by the transference of maternal antibodies, depending on their concentration and specificity, however still little is known about the mechanisms involving, in special in humans. We made this study aiming to characterize qualitatively and quantitatively the antibodies transmission directed to the main home dust allergen (Dermatophagoides pteronyssinus; Der p) through placental transference and maternal breastfeeding as well as to investigate the maternal sensitizing effect against to Der p in passive transference of these antibodies. For those objectives, we quantified by ELISA, IgG anti-Der p in paired samples of maternal blood and umbilical cord and anti-Der p S-IgA in colostrums of sensitized mother (n=13) and not sensitized (n=26); and we analyzed the functional activity of the same antibodies by avidity assays. The sensibility was determined in maternal sera by specific RAST (Cap System® Pharmacia). We show by the first time that anti-Der p S-IgA is transferred to the infant in very variable concentrations and with high levels of avidity, but is not dependent of maternal sensitization. We believe that breastfeeding is important, because it supplies S-IgA with the capacity to neutralize in a specific manner and block the entrance of Der p through mucosa, in infant of RAST+ mothers as well as of RAST-. We also demonstrate that total and specific to Der p IgG levels are more elevated in newborns of sensitized mothers when compared to of those of control mothers and non-sensitized indicating that the maternal sensitizing can influence the fetal immune response. In the other hand, the specific avidity of anti-Der p IgG was very similar between paired samples of umbilical cord and maternal sera, as well as in samples of study group and control group, suggesting thar the avidity index of IgG does not influence on placental transfer of specific antibodies. Once that the maternal antibody transference represent a important mechanism for immunomodulation of allergic response, we expect that a better understanding of the influence of maternal sensitivity on passive transfer of specific antibodies to babies will contribute with advances in the elaboration of adequate strategies of prevention of allergic sensitivity with more efficient therapeutic results.
49

Ghrelin Concentrations in Milk and Plasma of Dairy During Early Lactation

Alhojaily, Sameer 01 May 2014 (has links)
Ghrelin is a hormone produced mainly by the cells lining the gastric mucosa. Ghrelin was first extracted from human and rat stomachs, and identified as an endogenous stimulator of growth hormone release. Ghrelin is synthesized and produced in several tissues, but the gastric mucosa remains the major source of circulating ghrelin. Besides growth hormone release, ghrelin stimulates appetite and plays some major roles in different organs. In several studies, ghrelin was described as a hormone with multiple functions and diverse biological actions. Ghrelin exists in two major forms, active ghrelin and inactive ghrelin, and only the active from binds to the receptor. The majority of total circulating ghrelin is inactive ghrelin with no identified function. The aims of the present study were to measure active and total ghrelin in dairy cow’s milk and plasma during early lactation, and to observe changes in the ghrelin concentrations over time. We are interested in this period of time since the milk during early lactation contains a variety of biologically active hormones that are vital for newborn calves. In this study, fifteen Holstein dairy cows were selected randomly from different lactations. Milk and blood samples were taken daily from cows at early lactation for 10 days, and from some cows in mid-lactation. A laboratory test was used to measure active and total ghrelin in milk and plasma samples. Supplementary measurements such as milk fat, lactose, protein, and milk yield were recorded. Active and total milk ghrelin concentrations were found to be significantly higher in the first day of lactation during colostrum production. Interestingly, the percentage of active to total ghrelin in milk and blood was constant in all days tested, suggesting that this constant percentage can be used to estimate active or total ghrelin, if one of them is know, from the same sample. However, no correlation was observed between the percentage of milk ghrelin and plasma ghrelin or with other milk components. In conclusion, the presence of ghrelin in colostrum and milk in measurable amounts of both active and total form suggests that it is a critical compound for the metabolic activity of newborn calves and functions transiently to regulate the activity of some physiological processes until the endocrine system of the new calves starts to function independently.
50

Pre-weaned Dairy Calf Management: An Investigation into Colostrum Practices and Non-Invasive Measures of Chronic Stress

Jessica Dawn Kern (16648644) 02 August 2023 (has links)
<p>Dairy calves in the preweaning period are exposed to a variety of stressors (e.g. disbudding, castration, etc.) and management practices that have the potential to influence their health and productivity later in life. Proper colostrum management at birth is the first step in ensuring calves can reach their full potential in terms of health, growth, and development, while improper management increases a calf’s risk of failed transfer of passive immunity <strong>(FTPI)</strong> which puts the calf at an increased risk of morbidity and mortality. Previous research has indicated there is a difference in colostrum management practices between dairy bull and heifer calves. Due to the marketing of dairy-beef crossbred calves as surplus animals along with dairy bull calves, there is growing interest in the treatment of these calves on farms. The first study presented here (Chapter 2) investigated the relationship between colostrum management practices on 15 farms and the prevalence of FTPI between purebred dairy and dairy-beef crossbred calves on those farms. The results of this study found no influence of calf breed (purebred dairy or dairy-beef crossbred) on the prevalence of FTPI. However, farm tended to influence FTPI. There was also a significant influence of the reported timing of the first colostrum feeding on FTPI, with calves on farms reporting feeding colostrum within 1 hour of birth having decreased odds of experiencing FTPI. In addition to colostrum management at birth, calves are exposed to several management factors during the preweaning period that can cause stressful experiences and result in negative behavioral and physiological outcomes. Early life stress, especially chronic stress, can negatively impact calves later in life. Short term stress load in calves can be quantified by measuring cortisol in the blood serum or saliva; however, these measures are not reflective of chronic stress load because they only measure circulating cortisol. The second study (Chapter 3) considered the efficacy of utilizing hair cortisol concentration <strong>(HCC)</strong> as a measure of stress load in 27 dairy calves exposed to a weekly saline injection or a weekly or biweekly repeated acute stressor (Cosyntropin injection) during the preweaning period. The results revealed no difference in HCC between the treatment groups, though salivary cortisol was increased in calves injected with Cosyntropin. Additionally, calf behavior and growth were not influenced by the treatments in this study. Overall, these studies provided insights into two areas that have not been extensively researched. First, considering dairy-beef crossbred calf management, and second investigating a method to assess chronic stress that has not been extensively researched in calves.</p>

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