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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.
51

Evaluation of alternative forage species to reduce risk for cow-calf production systems in the Appalachian region

Newman, Christina Louise 22 December 2010 (has links)
Optimizing forage productivity is essential to reduce pasture seasonality and ensure available forage to meet the nutritional needs of livestock. This study explores the risk-buffering ability of warm-season forages to fill the summer slump gap in production of cool-season grasses. Small plot experiments were initiated in summer of 2008 in Kentland Farm, Northern Piedmont AREC and Shenandoah AREC, Virginia. Treatments included endophyte-infected tall fescue (KY31 E+), endophyte free tall fescue (KY31 E-), novel endophyte tall fescue (MaxQ), Crabgrass in combination with endophyte-infected tall fescue, Teff, Bermudagrass (BG), and Caucasian bluestem (CB). Plots were harvested May through October of 2009 and 2010 at the late boot stage at a cutting height of 10cm. Subsamples were analyzed for dry matter and nutritive value. To assess risk, bootstrap distributions of biomass and quality data were generated by Monte Carlo simulation and compared against an objective function defined as 59 kg ha-1 d-1 forage yield; 10% CP; 60% TDN. Regardless of variability, warm-season grasses produced biomass yields and nutritional values adequate to fill the summer slump from cool-season forages and demonstrated a higher probability of meeting the minimum requirements in July, August and September. Teff was most consistent in meeting the minimum requirements in mid-summer. However, with good conditions for establishment, both BG and CB can help to fill the gap in summer months when compared to cool-season tall fescue. Bootstrap distributions provide producers with a tool that links their production goals with a measurable value of production risk. / Master of Science
52

In vivo and modeling approaches to improve prediction of phosphorus availability in ruminants

Feng, Xin 04 June 2015 (has links)
Improving prediction of P availability necessitates understanding of P digestion and absorption mechanism in ruminants. Greater knowledge of the interaction of P with other nutrients and the utilization of dietary P in the digestive tract will improve our ability to optimize P feeding and reduce P runoff in agricultural areas. In vivo experiments were performed and the data were used to reparamterize a model regarding P digestion and metabolism. The interaction of P and iron was investigated in lactating dairy cows by infusing 0, 200, 500, or 1250 mg/d Fe (equivalent to 0, 2, 5, or 12.5 mg Fe/L in drinking water) in the form of ferrous lactate solution into the abomasum of lactating cows. Phosphorus absorption was not negatively influenced by abomasally infused ferrous lactate, and the highest infusion (1250 mg Fe/d) approximates a drinking water iron content far above that found in most samples from the field. In the second study the effects of dietary P intake on intestinal P absorption was evaluated in eight growing Holstein steers fitted with permanent duodenal and ileal cannulas. Diets varying in P content (0.15%, 0.27%, 0.36% and 0.45%, DM basis) were fed , and increasing P intake increased the quantity of P absorbed from the small intestine linearly without affecting the absorption efficiency (mean = 59.6%). Only a small portion of P absorption occurred in large intestine and this was not affected by dietary P concentration. An absence of change of salivary P secretion at low dietary P suggested rumen function was prioritized during short-term P deficiency. Finally the data from these experiments along with four other studies were used to parameterize the P digestion and metabolism model of Hill et al. (2008) to provide a better understanding of the digestion and metabolism of P fractions in cattle. The data used were adequate to parameterize the digestive elements of the model with good precision, and the model structure appears to be appropriate with no significant mean or slope bias. The resulting model could be used to derive P bio-availabilities of commonly used feedstuffs in cattle production. Although the model explained the data used with no apparent bias, this does not guarantee that the model parameters are valid for all conditions. Additional data are needed to evaluate this model in a wider range of scenarios. / Ph. D.
53

The Optimal Cow Size for Intermountain Cow-Calf Operations: The Impact of Public Grazing Fees on the Optimal Cow Size

Russell, Jesse 01 May 2014 (has links)
The cattle industry is very competitive which is forcing cow-calf producers to strive for efficiency. Research has shown that as a cows mature weight increases, feed efficiency decreases, as well as reproductive efficiency and other production factors. The purpose of this paper is to (1) identify the economically optimum cow size when charging for grazing public lands on a true Animal Unit Equivalent (AUE) basis and (2) determine if the current practice of charging on a per head basis for grazing public lands has an effect on the optimal cow size. To simplify the complexity of this problem, three different resource bases common in the Intermountain West (resource base 1, time grazing = 100%; resource base 2, time grazing = 75%; and resource base 3 time grazing = 50%) were defined, as well as three different weights of cattle (small, medium and large). Grazing plans were created for each resource base and winter rations were balanced to ensure adequate nutrition and accurate budgeting. Linear programming was used to determine an optimal cow size for each resource base when charging on a per head basis and by a true AUE. When grazing on public land was charged on a true AUE basis, the small cows generated the highest net returns on all resources. Also, each resource base was able to maintain a larger number of the smaller cows than the medium or large cows under these conditions. When grazing on public lands was charge on a per head basis, as is typical, the large cow generated the greatest net returns on resource base 1 and 2. However, the small cow generated the greatest net return on resource base 3. These findings suggest that the current practice of charging for grazing public land on a per head basis does have an impact on cow size.
54

Dairy Cow Activity as a Potential Management Tool for Detection of Clinical Mastitis

McCullough, Kathryn E. 18 September 2015 (has links)
No description available.
55

The Effects of Increased Metabolizable Protein in Fresh Dairy Cattle throughout Peak Lactation

Carder, Ethan G. 19 December 2016 (has links)
No description available.
56

The effect of the anti-inflammatory drug sodium salicylate in mature periparturient dairy cattle and immortalized bovine mammary epitheilal (MAC-T) cells

Montgomery, Shawnee January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Barry Bradford / During the transition period, 3 wk before to 3 wk after calving, dairy cows experience a variety of sudden hormonal and metabolic shifts that could result in metabolic disorders or diseases, which can be detrimental to the productive life and longevity of the cow. Cows undergo a negative energy balance, where they cannot consume enough feed to meet their energy requirements. To make up this deficit, cows mobilize adipose tissue in the form of non-esterified fatty acids (NEFA) which are transported to the liver and are either used for fuel or stored as triglycerides. High levels of circulating NEFA can lead to endoplasmic reticulum (ER) stress, which is linked to inflammation. This low-grade inflammation can compromise cell function. To mitigate this inflammation, sodium salicylate, a non-steroidal anti-inflammatory drug (NSAID), was given to mature (3+ parity) cows for 7 d after parturition via their drinking water. Blood was collected daily and a glucose turnover assay was performed. Liver, muscle, and adipose tissue was collected on d 7. Overall, it appeared that SS increased insulin sensitivity and depressed gluconeogenesis post-transcriptionally. Multiple in vitro studies were performed on immortalized bovine mammary epithelium (MAC-T) cells to determine the action of SS when ER stress was induced with palmitate (PALM). Treatment with SS did not mitigate, and in some cases exacerbated, the ER stress response. The addition of bovine serum albumin (BSA), a common component of cell culture media, may alter reactive oxygen species (ROS) measurements due to its antioxidant property. Overall, SS seems to alter metabolic processes and the cellular response to stress.
57

Concentrações plasmáticas de progesterona e eficiência reprodutiva de diferentes dispositivos de liberação lenta de progesterona usados em inseminação artificial em tempo fixo / Plasmatic progesterone concentration and reproductive efficiency of different intravaginal progesterone devices used in timed artificial insemination

Valentim, Renato 25 November 2004 (has links)
Quatro experimentos foram realizados para avaliar as concentrações plasmáticas de progesterona ([P4]) e as taxas de fertilidade na inseminação artificial em tempo fixo (IATF) após o uso de diferentes dispositivos de liberação lenta de progesterona (DP). No primeiro experimento foram utilizadas 4 novilhas ovariectomizadas. Esses animais receberam 5 diferentes tipos de DP, nos quais se variou a superfície de contato (50cm² ou 100 cm² e a dose de progesterona (0,5g; 1,0g e 2,0g) Os dispositivos foram inseridos aos pares durante 7 dias e se estabeleceu um intervalo entre tratamentos de pelo menos 30 dias. Com os dados de [P4] 24 horas e sete dias após a inserção do DP obtiveram-se as seguintes equações de regressão, respectivamente: [P4]24h = 0,238 + 0,0343(área) + 0,513(dose); (R²=0,94) e [P4] 7d = 0,331+ 0,0056(área) + 0,329(dose); (R²=0,71). No segundo experimento foram comparados dois dos dispositivos testados no primeiro estudo: P50-1,0 (50 cm2 área; 1,0g dose P4) e P50-1,5 (50 cm² área; 1,5g dose P4) com dois dispositivos comerciais: CIDR (120 cm² área; 1,9g P4 dose) e DIB (120 cm² área; 1,0g P4 dose). Os dispositivos foram inseridos em 15 novilhas Nelore pré-puberes para avaliação das [P4] obtendo-se, após 24 horas de inserção, para CIDR, DIB, P50-1,5 e P50-1,0, respectivamente: 7,7±2,8ª ; 4,5±0,75b; 5,9±2,5b e 2,1±0,5c ng/ml e após 8 dias, respectivamente: 3,3±0,7ª ; 2,6±2,0ª; 3,0±2,4ª e 1,1±0,27bng/ml. As regressões obtidas no primeiro experimento não foram eficientes para estimar as [P4] obtidas no estudo 2. Nos experimentos 3 e 4 comparou-se a eficiência dos dispositivos DIB e P50-1,5 em 431 vacas de corte zebuínas e cruzadas, com bezerros ao pé e multíparas, após uso em um programa de IATF no qual os dispositivos permaneciam nos animais durante 8 dias; quando da colocação desses dispositivos, eram aplicados 2mg de benzoato de estradiol (BE) e, na retirada, 400UI de eCG. Uma última dose de BE foi administrada 24 horas após a retirada dos DP, e a IATF foi realizada 54 horas após a retirada dos DP. Não foram encontradas diferenças nas taxas de concepção da IATF entre dispositivos. As taxas de concepção variaram entre 30 e 51,6% nos lotes tratados. O tratamento diminuiu o intervalo tratamento-parto de 365 para 317 dias, comparado à monta natural. / Four studies have been made to evaluate the plasmatic progesterone concentration ([P4]) of different intravaginal low delivery progesterone devices (PD) and the fertility rates after their use in timed artificial insemination (TAI). In the first study there were used 4 ovariectomized heifers. These animals received 5 kinds of prototypes PD on which varied the contact surface (50 or 100 cm²) and the progesterone doses (0,5; 1,0 or 2g). These PD were inserted in the vaginas in pairs and the interval between treatments was higher than 30 days. With the data of [P4] there were found the fallowing regressive equations for the days 1 and 7 after the insertion , respectively: [P4]24h = 0,238 + 0,0343(surface) + 0,513(dose); (R²=0,94) and [P4]7d = 0,331+ 0,0056(surface) + 0,329(dose); (R²=0,71). In the second study there were compared 2 prototypes PD based on the first study: P50-1,0 (50 cm² surface; 1,0g dose P4) and P50-1,5 (50 cm² surface; 1,5g dose P4) with two commercial PD: CIDR (120 cm² surface; 1,9g P4 dose) and DIB (120 cm² surface; 1,0g P4 dose). These PD were inserted in 15 prepuberal Nelore heifers to evaluate the [P4] The [P4] (in ng/ml) found after 24 hours were for CIDR, DIB, P50-1,5 e P50-1,0, respectively: 7.7±2.8ª ; 4.5±0.75b; 5.9±2.5b e 2.1±0.5c ng/ml and after 8 days, respectively: 3.3±0.7ª ; 2.6±2.0ª; 3.0±2.4ª e 1.1±0.27b ng/ml. The regressive equations found in the first study were not efficient to estimate the [P4] for the prototypes PDs. In the studies 3 and 4 there were compared the PD DIB and P50-1.5 for TAI in 431 Nelore and cross-breed lactating postpartum beef cows. The TAI protocol was: PD insertion per 8 days, administration of 2 mg estradiol benzoate (EB) in the insertion day - 400 UI of eCG in the PD removal - 1mg EB 24 hours after PD removal- TAI 54 hours after the PD removal. There were no differences in TAI conception rates between PD. The TAI conception rates ranged from 30 to 51.6% in the treated herds. The treatment has decreased the treatment-partum interval from 365 to 317 days on animals submitted to natural mating.
58

Measuring rumination and physical activity as a tool for fresh cows health monitoring / Medição da ruminação e da atividade fisica como ferramenta no monitoramento de saúde de vacas recém paridas

Silva, Manuel Agustín 17 March 2017 (has links)
The objectives of the current experiment were to characterize patterns of daily rumination time, activity and milk production around the diagnosis of health disorders, and to determine if the addition of rumination and activity data to a commercial dairy farm fresh cow health monitoring program improves sick cow detection and diagnosis of disease during the first 30 DIM. Holstein animals (primiparous = 282, parous = 328) were enrolled in the experiment approximately 60 d before expected calving date, and were divided into two groups (Collar Monitoring-CM-, n=293 ; Control-C-, n=317). Electronic rumination and activity monitoring tags (SCR Engineers Ltd., Netanya, Israel) were fitted on cows neck at enrollment and were kept until approximately 80 ± 3 DIM. Farm personnel checked the cows and performed the diagnosis of disease following the routine of the dairy. Cows from both of the groups were sent to check based on the parameters used by the farm. Additionally, cows from group CM were checked based on the data provided by the tags. Serum calcium concentration was determined using blood samples collected from 0 to 4 DIM. BHBA concentration was determined twice using blood samples collected from 4 to 12 DIM and 7 to 20 DIM. Subclinical hypocalcemia (SCHC) and subclinical ketosis (SCK) were characterized as Ca <8.55 ng/dL, and BHBA >1,000 µmol/L in any blood sample, respectively. Daily rumination time (DRT), daily activity (ACT), and daily milk production patterns for cows with clinical disease showed differences with healthy cows around diagnosis (P $lt;0.05). Cows with subclinical disorders and calving problems had changes in DRT, ACT, and milk production patterns compared to healthy cows around calving (P <0.05). DRT and ACT patterns of regrouped cows were characterized by differences with non-regrouped cows around regrouping (P <0.05). No differences were found for DRT, ACT, and milk production between groups C and CM. The overall sensitivity (Se) of collars to identify health disorders was 56.4% (n = 402 cases), considering a positive outcome as at least 1 alert based on rumination and activity from -7 to +2 d relative to diagnosis. Se was higher for cows with more than one disorder (75.8%) than for cows with one disease only (45.5%) (P <0.001). No differences between groups were found for overall Se, and Se for cows with one disease. However, for cows with more than one disorder, Se was higher in group CM than C (P = 0.005). Overall specificity, positive predicted values, and negative predicted values were 74.5%, 46.4%, and 57.6%, respectively. The overall incidence of disease was 48%. No differences between groups were found for overall incidence of disease and each disease. Among primiparous, group CM (43.3%) had higher overall incidence of disease than group C (32.1%) (P = 0.05). Although were not differences for parous, incidence of metritis tended to be greater in group C than CM (P = 0.1). Incidence of SCK and SCHC was not different between groups. A higher percentage of animals from group CM than C received treatment (P = 0.04), and these differences were seen in primiparous (P = 0.03), but not in parous. However, a higher percentage of parous not diagnosed as sick from group CM received support treatments (drenching and fluids) compared to C. No differences were shown for culling rate, service rate until 150 DIM, conception rate at first service, and percentage of cows marked as do not breed between groups. DRT and ACT patterns for sick cows showed differences around diagnosis compared to healthy cows. The use of DRT and ACT data was able to identify sick cows in a commercial dairy farm. Results suggest that it may be also useful to identify cows needing attention before clinical signs are visible, improving the prevention of health disorders. Its usefulness may vary according to parity, disease, severity of disease and health compromise, and the intensity of the farm system for checking cows. Future research should evaluate different parameters and parameters thresholds based on rumination and activity data for identifying sick cows, and their efficiency in dairies with different degrees of intensity for checking animals health. / Os objetivos deste experimento foram caracterizar os padrões diários do tempo de ruminação, atividade, e produção de leite arredor do diagnostico de doenças, e determinar se a adição de dados de ruminação e atividade num programa de monitoramento de saúde de vacas de uma fazenda comercial melhora a detecção de vacas doentes e o diagnostico de doenças durante os primeiros 30 DEL. Animais Holstein (primíparas = 282, multíparas = 328) foram utilizados no experimento aproximadamente 60±3 dias antes da data esperada de parto, e foram divididos em dois grupos (Collar Monitoring-CM-, n=293; Control-C-, n=317). Dispositivos eletrônicos para o monitoramento da ruminação e atividade acoplados a colares (SCR Engineers Ltd., Netanya, Israel) foram colocados nas vacas no enrolamento e mantidos ate aproximadamente 80±3 DEL. O monitoramento de saúde das vacas e o diagnostico de doenças foram realizados pelos funcionários da fazenda seguindo a rotina do estabelecimento. Os animais dos dois grupos foram enviados para checagem de saúde baseados nos parâmetros utilizados pela fazenda. Adicionalmente, as vacas do grupo CM foram checadas baseadas na informação suprida pelos colares. A concentração de cálcio sérico foi determinada usando uma amostra de sangue coletada do dia 0 ao 4 em leite. A concentração de beta-hidroxibutirato (BHBA) foi determinada duas vezes usando amostras de sangue coletadas do dia 4 ao 12, e do 7 ao 20 do posparto. Hipocalcemia subclínica (SCHC) e cetose subclínica (SCK) foram caracterizadas como Ca <8.55 ng/dL, e BHBA >1000 µmol/L em qualquer amostra, respectivamente. Os padrões diários do tempo de ruminação (DRT), atividade (ACT), e produção de leite de vacas com doenças clinicas arredor do diagnostico mostraram diferencias comparados com vacas sadias (P <0.05). Vacas com alterações subclínicas e problemas de parto tiveram alterações nos padrões de DRT, ACT, e produção de leite arredor do parto, quando comparadas a vacas controle (P <0.05). Padrões de DRT e ACT de vacas reagrupadas se caracterizaram por diferencias com vacas não reagrupadas (P <0.05). Não foram achadas diferencias em DRT, ACT, e produção de leite entre os grupos C e CM. A sensibilidade (Se) dos colares para identificar problemas de saúde foi de 56.4% (n = 402 casos), considerando como evento positivo a ocorrência de pelo menos uma alerta baseada em ruminação e atividade dentro dos 7 dias prévios ate 2 dias apos o diagnostico de doença. A Se foi maior para vacas com mais de uma doença (75.8%) que em para vacas com uma doença somente (45.5%) (P <0.001). Não se acharam diferencias na Se geral, nem Se para vacas com uma doença somente entre grupos. Porem, a Se foi maior no grupo CM que no grupo C (P = 0.005) em vacas com mais de uma doença. A especificidade (Sp), valores da predição positiva (PPV), e valores da predição negativa (NPV) foram 74.5%, 46.4%, e 57.6%, respectivamente. A incidência de doença foi de 48%. Não houve diferencias entre grupos na incidência de doença, nem na incidência de cada doença. Entre as primíparas, o grupo CM (43.3%) teve maior incidência de doença do que o grupo C (32.1%) (P = 0.05). Embora não teve diferencia na incidência de doença entre grupos para multíparas, a incidência de metrite teve uma tendência a ser maior no grupo C do que no grupo CM (P = 0.1). A incidência de SCK e SCHC não foi diferente entre grupos. Maior percentagem de animais do grupo CM recebeu tratamento do que do grupo C (P = 0.04), e estas diferencias foram observadas em primíparas (P = 0.03), mas não em multíparas. Contudo, uma maior percentagem de animais não diagnosticados como doentes do grupo CM recebeu tratamentos de suporte, quando comparado ao grupo C. Não se acharam diferencias na taxa de descarte, taxa de serviço aos 150 DEL, taxa de concepção ao primeiro serviço, e percentagem de vacas de descarte reprodutivo entre grupos. Resumindo, os padrões de DRT e ACT de vacas doentes arredor do diagnostico de doença mostraram diferencias comparados com os de vacas sadias. O uso da informação de DRT e ACT foi capaz de identificar vacas doentes numa fazenda comercial. Os resultados sugerem que a utilização dos colares pode ser util para identificar vacas com necessidade de atenção antes da aparição de sinais clínicos visíveis, melhorando a prevenção de problemas de saúde. A utilidade da utilização do sistema pode variar de acordo a ordem de partos dos animais, doença em questão, severidade da doença e comprometimento de saúde do animal, e com a intensidade do sistema de monitoramento de saúde dos animais da fazenda. Próximas pesquisas deveriam avaliar diferentes parâmetros baseados na informação de ruminação e atividade para identificar vacas doentes, e a sua eficiência em fazendas com diferentes graus de intensidade para o monitoramento de saúde.
59

Distribuição espacial de transcritos no trato reprodutivo e sua relação com o ambiente endócrino periovulatório no início do diestro de bovinos de corte / Different periovulatory endocrine milieus modulate spatial distribution of transcripts in the reproductive tract of beef cows

Araujo, Estela Rose 30 May 2014 (has links)
Em bovinos , as flutuações nas concentrações de estradiol (E2) e progesterona ( P4) que ocorrem em torno do estro modulam a expressão gênica do endométrio, a composição histotrofo, o desenvolvimento do concepto e assim afetam o resultado da prenhez. Durante o ciclo estral, ações endócrinas bem orquestradas afetam o endométrio bovino (BAUERSACHS et al., 2005). No presente trabalho, a hipótese sustentada é que alterações endócrinas associadas ao crescimento e ovulação de folículos de diferentes tamanhos modulam a distribuição espacial das transcrições no trato reprodutivo de vacas da raça Nelore. O crescimento folicular de vacas Nelore multíparas e não lactantes foi farmacologicamente manipulado a fim de gerar grupos com folículos pré-ovulatórios e subsequente corpo lúteo (ou seja, diferentes ambientes endócrinos periovulatórios) grande (FG CLG; n = 6) ou pequeno (FP CLP, n = 6). Os animais foram abatidos, sete dias após a indução da ovulação e fragmentos das regiões anterior, média e posterior de ambos os cornos uterinos e da vagina foram coletados para a avaliação de expressão gênica por PCR quantitativo. A expressão gênica foi normalizada utilizando os genes referência ciclofilina A e beta actina, como indicado pelo software GeNorm. Os dados foram analisados utilizando-se o procedimento PROC MIXED do SAS (versão 9.2; Instituto SAS) em dois modelos independentes. O primeiro modelo incluiu os efeitos de grupo (FG CLG e FP CLP), lado do corno uterino (ipsolateral ou contralateral ao ovário contendo o CL) e sua interação, o segundo modelo incluiu os efeitos de grupo, região (anterior, médio e posterior) do corno ipsolateral e suas interações. Vacas do grupo FP CLP apresentou maiores folículos pré-ovulatórios e concentrações de E2 durante proestro e maiores CL e níveis de P4 no diestro inicial, quando comparados com os do grupo FP CLP. Animais do grupo FP CLP apresentaram uma maior abundância de transcritos que codificam o receptor de E2 (ESR2; 130%), a aldo-ceto redutase família 1, membro C4 (AKR1C4; 232%), a lipoproteína lipase (LPL; 116%), o carreador de soluto família 2, membro 1 (SLC2A1; 24%) e inibidor da peptidase da serina, subtipo A, membro 14 (SERPINA14; 75%). Por outro lado, a expressão de genes que codificam o receptor de P4 e receptor de oxitocina foi regulada positivamente no tecido endometrial do grupo FP CLP (36 % e 966 %, respectivamente). Além disso, a abundância da transcrição desse genes foi maior no corno contralateral ao CL. Além disso, a região anterior do corno uterino ipsolateral apresentou aumentada expressão de PGR, ESR2, LPL, SLC2A1 e SERPINA14 em comparação com a região posterior. Com exceção da OXTR que apresentou interação grupo e lado, não houve interações grupo por lado ou região. Não houve efeito de grupo sobre a expressão de qualquer um dos genes na vagina. Em conclusão, o presente estudo mostrou que o padrão de expressão de genes específicos em resposta variou quanto a grupo e entre as regiões do trato reprodutivo de fêmeas bovinas. No entanto, os distintos ambientes endócrino periovulatórios não afetaram a distribuição regional de transcritos. / In cattle, fluctuations of progesterone (P4) and estradiol (E2) concentrations that occur around estrus modulate endometrial gene expression, histotroph composition, conceptus development and, thereby affect pregnancy outcome. During the estrous cycle, well-orchestrated endocrine actions affect the bovine endometrium (BAUERSACHS et al., 2005). In the present work, we hypothesized that endocrine changes associated with growth and ovulation of follicles of different sizes modulate the spatial distribution of transcripts in the reproductive tract of Nellore cows. The follicular growth of multiparous non-lactating Nelore cows was pharmacologically manipulated in order to generate groups with large (LF LCL; n=6) or small (SF SCL; n=6) preovulatory follicles and subsequent corpus luteum (i.e., different periovulatory endocrine milieus). Cows were slaughtered seven days after the induction of ovulation and fragments from the anterior, middle and posterior regions from both uterine horns and the vagina were collected. Gene expression assessment was performed by quantitative PCR. Gene expression was normalized using cyclophilin A and actin, beta as reference genes, as indicated by the GeNorm software. Data were analysed using the PROC MIXED procedure of SAS (Version 9.2; SAS Institute) in two independent models. The first model included the effects of group (LF LCL and SF SCL), side of the uterine horn (ipsilateral or contralateral to the ovary containing the CL) and interaction and the second model included the effects of group, region of the ipsilateral horn (anterior, middle and posterior) and interaction. Cows in the LF LCL group presented larger preovulatory follicles and E2 concentrations during proestrus and larger CL and P4 levels during early diestrus when compared to animals from SF SCL group. Animals in the LF LCL group had a greater abundance of transcripts coding the estrogen receptor (ESR2; 130%), aldo-keto reductase family 1, member C4 (AKR1C4; 232%), lipoprotein lipase (LPL; 116%), solute carrier family 2, member 1 (SLC2A1; 24%) and serpin peptidase inhibitor, clade A member 14 (SERPINA14; 75%). Conversely, the expression of genes coding the progesterone receptor and oxytocin receptor was upregulated in the SFSCL endometrial tissue (36% and 966% respectively). Furthermore, transcript abundance of the later genes was observed in the contralateral horn. In addition, the anterior region of the ipsilateral horn showed increased expression of PGR, ESR2, LPL, SLC2A1 and SERPINA14 compared to the posterior region. Except for a group by side interaction for the expression of OXTR, there were no group by region or group by side interactions. There was no effect of group on the expression of any of the genes in the vagina. In conclusion, our study showed that the expression pattern of specific genes varied in response to group and among regions of the female reproductive tract. However, distinct endocrine periovulatory milieus did no affect regional distribution of transcripts.
60

Effects of anemia on periparturient cows / Efeitos da anemia em vacas periparturientes

Paiano, Renan Braga 09 March 2018 (has links)
The objectives of this study were to characterize the hematological and productive pattern during the peripartum in cows with and without anemia, as well as to evaluate the erythrogram in animals that presented metritis puerperal acute (MPA), lameness, acetonemia, increased non-esterified fatty acids (NEFA) and cows with different categorization of body condition score (BCS). In study 1, 50 Holstein cows (29 multiparous and 21 primiparous) were used. Blood samples and physical examination were performed at 13 different times: 18 ± 3, 12 ± 2, 5 ± 1, and 2 ± 1 before calving, and 7, 14, 21, 30, 45 and 60 days postpartum. Erythrogram evaluations were performed, and red blood cell count (RBC), hemoglobin concentration, packed cell volum (PCV), and absolute hematimetric values of mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin, RDW, serum concentrations of iron, betahydroxybutyrate (BHBA), AGNE and total bilirubin (TBIL) were determined for the biochemical analyzes. Anemia was classified according to hemoglobin values <7 g / dL and globular volume <24%. The prevalence of anemia was higher in the period 60 days postpartum affecting 18.3% of the animals, the pattern of anemia presented was normocytic, normochromic, regenerative. RBC, PCV and hemoglobin were lower (P <0.05) for animals with anemia. While the animals with MPA and lameness the value of the erythrogram was very similar throughout the postpartum period. No difference was observed between the groups according to the values of NEFA, BCS and loss of BCS during the periods performed in the postpartum period. In conclusion the anemic animals presented the values of the physical examination according to the physiological limits, the anemia did not cause productive losses in the affected animals. It was not evidenced that animals with MPA and claudicants presented a greater reduction of blood crass, excluding the occurrence of inflammatory anemia, and although the prevalence of anemia increased during postpartum, it was not possible to characterize the main cause of the reduction of hematological values between the categorizations. In the second study, blood was sampled from 336 animals (252 multiparous and 84 primiparous) between 21 and 30 days in lactation (DEL) on 7 farms in the State of São Paulo with the objective of characterizing the prevalence of anemia in dairy cows, prevalence of anemia in different categorizations such as: lactation number, BCS at the time of collection, dystocia, retention of fetal membranes, mastitis, digestive problem, lameness and acetonemia, , as well as the analysis erythrogram, biochemical profile, BCS, and milk production among animals with and without anemia. In conclusion, the prevalence of anemia was low (16.3%) and no association with the categorizations performed in this study, it was not possible to characterize the cause of anemia through biochemical analysis. / Os objetivos deste estudo foi caracterizar o padrão hematológico e produtivo durante o periparto em vacas com e sem anemia, assim como avaliar o eritrograma em animais que apresentaram metrite puerperal aguda (MPA), claudicação, acetonemia, valores de ácidos graxos não esterificados aumentados (AGNE) e vacas com diferentes categorizações de escore de condição corporal (ECC). No estudo 1, foram utilizadas 50 vacas Holandesas (29 multíparas e 21 primíparas), foram realizadas colheitas sanguíneas e exame físicos em 13 momentos diferentes: 18 ± 3, 12 ± 2, 5 ± 1, e 2 ± 1 antes do parto, parto, e 7, 14, 21, 30, 45 e 60 dias após o parto. Foram realizadas avaliações do eritrograma sendo mensurado a contagem de hemácias (RBC), concentração de hemoglobina, volume globular, além dos valores hematimétricos absolutos do volume corpuscular médio (VCM), concentração hemoglobínica corpuscular média (CHCM), hemoglobina corpuscular média (HCM) e RDW, para as análises bioquímicas foram determinadas a concentração sérica de ferro, betahidróxidobutirato (BHBA), AGNE e bilirrubina total (TBIL). Anemia foi classificada de acordo com os valores de hemoglobina < 7 g/dL e o volume globular < 24 %. A prevalência de anemia foi maior no período 60 dias após o parto afetando 18.3% dos animais, o padrão da anemia apresentado foi normocítica, normocrômica, regenerativa. Os valores das contagens de hemácias, volume globular e hemoglobina foram menores (P < 0.05) para os animais com anemia. Enquanto os animais com MPA e com claudicação, o valor do eritrograma foi muito semelhante ao longo do pós-parto. Não foi observado diferença entre os grupos de acordo com os valores de AGNE, ECC e perda de ECC durante as coletas realizadas no pós-parto. Em conclusão os animais anêmicos apresentaram os valores do exame físico de acordo com os limites fisiológicos, a anemia não provocou perdas produtivas nos animais afetados. Não foi evidenciado que animais com MPA e claudicantes apresentassem maior redução da crase sanguínea, excluindo a ocorrência de anemia inflamatória, sendo que embora a prevalência de anemia aumentasse durante o pós-parto não foi possível caracterizar a causa principal da redução dos valores hematológicos entre as categorizações realizadas. No estudo 2, foram realizadas coletas sanguíneas em 336 animais (252 multíparas e 84 primíparas) entre 21 e 30 dias em lactação (DEL) em 7 fazendas no Estado de São Paulo com objetivo de caracterizar a prevalência de anemia nos animais, prevalência de anemia em diferentes categorizações realizadas como: distocia, retenção dos anexos fetais, mastite, problema digestivo, claudicação, acetonemia, ECC no momento da coleta e número de parto, assim como a análise do eritrograma, bioquímico e ECC e produção de leite entre os animais com e sem anemia. Em conclusão a prevalência de anemia foi baixa prevalência (16.3 %) e nenhuma associação com as categorizações realizadas nesse estudo, adicionalmente não foi possível caracterizar por meio de análises bioquímicas a causa da anemia.

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