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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.
1

Reflex pathways controlling oxytocin cells in the supraoptic and paraventricular nuclei during suckling in the rat

Juss, T. S. January 1987 (has links)
No description available.
2

Relação entre os padrões de secreção central e periférica de ocitocina: implicações sobre produção de leite em ovelhas / Relation between central and peripheral oxytocin realese: implications on milk production in sheep

Bochini, João Carlos 07 August 2008 (has links)
Esse projeto de pesquisa teve como objetivo estudar simultaneamente as concentrações da ocitocina no líquido cefalorraquidiano (LCR) e no plasma de ovelhas multíparas durante a ordenha, estabelecendo suas possíveis correlações entre os dois compartimentos corporais, bem como em relação à produção e ejeção do leite. Para tanto, foram utilizadas 10 ovelhas multíparas (Ovis aries) da raça Santa Inês apresentado peso médio de 40 Kg. Os animais foram divididos em quatro grupos, sendo eles: ordenha mecânica exclusiva (OME; cordeiros apartados 3 dias após o parto), manejo misto com ordenha mecânica (MMom; cordeiros permanecem com as mães durante o período diurno, após a ordenha mecânica, sendo apartados durante a noite), manejo misto com ordenha manual (MMoma) e amamentação exclusiva (AE; cordeiros apartados durante o período noturno). Para a obtenção de LCR foram realizadas a punção do espaço subaracnóideo e implantação de um cateter epidural, enquanto que o plasma foi colhido com o auxílio de um scalp. As amostras de LCR e sangue foram coletadas simultaneamente antes (-0,5 min), durante (0,5; 1 e 4 min) e após (10; 15 min) a amamentação ou ordenha para posterior quantificação das concentrações de ocitocina por ensaio imunoenzimático. Foi obtido um total de 503 amostras, sendo 241 de LCR e 262 de plasma. As estimativas de média, desvio padrão, coeficiente de variação, mínimo e máximo para as concentrações de ocitocina no LCR e plasmáticas foram 257,880 ± 265,90 pg/ml; 103,11%; 11,70 pg/ml e 1000,00 pg/ml, respectivamente. A análise estatística não revelou correlação significante entre LCR e plasma para os quatros grupos experimentais avaliados. O coeficiente de correlação para os grupos OME, AE, MMom e MMoma foram, respectivamente: -0,26, -0,19, 0,05 e 0,04. Com relação ao LCR, não ocorreu diferença significante entre os 4 grupos experimentais em relação às concentrações de ocitocina. Já para o plasma, os animais do grupo MMom (679,80 ± 25,63) e MMoma (591,82 ± 30,56) apresentaram maiores concentrações plasmáticas médias de ocitocina em relação a OME e AE. Assim também, o grupo OME (381,04 ± 22,09) apresentou maior concentração média de ocitocina em relação ao grupo AE (218,82 ± 27,04). Conclui-se que, não existe correlação positiva entre as concentrações de ocitocina central e na circulação periférica durante a ordenha ou amamentação. Os padrões de liberação de ocitocina plasmática diferem de acordo com o tipo de manejo ao qual o animal é submetido, o que pode ter conseqüências para a ejeção do leite e conseqüentemente, para a produção. Finalmente, as concentrações de ocitocina presentes no LCR não sofrem influência do tipo de manejo de ordenha ao qual o animal foi submetido, ao contrário daquilo que foi observado para o plasma. / The aim of the present work was to study a possible relationship between central and peripheral oxytocin release and its consequences to milk production during milking in experimental ewes. Ten multiparous Santa Ines ewes (Ovis aries) were divided in 4 groups according to milk ejection stimuli: exclusive machine milking (OME), mixedmanagement of milking and suckling (MMom: lambs separated during night and reunited to their mother after morning milking; MMoma: mixed-management with manual milking) and exclusive suckling (AE: lambs separated also during night). Cerebrospinal fluid (CSF) was collected through a implanted sub-arachnoid catheter and plasma was collected from the jugular vein. imultaneous sampling was performed at -0.5, 0.5, 1, 4, 10 and 15 min (0 min was teat attachment to either machine or manual milking system or lamb suckling). A total of 241 samples of CSF and 262 plasma samples were processed and oxytocin concentrations were quantified by immunoenzimatic assays. Estimated means, standard deviation, variation coefficient and minimum and maximun values of CSF and plasma oxytocin concentrations were, respectively: 257.880 ± 265.90 pg/ml; 103.11%; 11.70 pg/ml e 1000.00 pg/ml. No statistical strong positive correlations (OME= -0.26, AE= -0.19, MMom= 0.05 and MMoma= 0.04) were found between CSF and plasma samples. Also, CSF was not influenced by milk ejection stimuli, although plasmatic oxytocin was higher in MMom (679.80 ± 25.63) and MMoma (591.82 ± 30.56) compared to OME and AE. In addition, OME (381.04 ± 22.09) plasmatic oxytocin concentration was higher when compared to AE (218.82 ± 27.04). In conclusion, no positive correlations between central and peripheral oxytocin concentrations were observed during milking or suckling. Plasma oxytocin oncentrations differ as a function of management and have consequences to milk ejection as well as to milk production Also, plasma, but not CSF oxytocin, was influenced by different milk ejection stimuli.
3

Relação entre os padrões de secreção central e periférica de ocitocina: implicações sobre produção de leite em ovelhas / Relation between central and peripheral oxytocin realese: implications on milk production in sheep

João Carlos Bochini 07 August 2008 (has links)
Esse projeto de pesquisa teve como objetivo estudar simultaneamente as concentrações da ocitocina no líquido cefalorraquidiano (LCR) e no plasma de ovelhas multíparas durante a ordenha, estabelecendo suas possíveis correlações entre os dois compartimentos corporais, bem como em relação à produção e ejeção do leite. Para tanto, foram utilizadas 10 ovelhas multíparas (Ovis aries) da raça Santa Inês apresentado peso médio de 40 Kg. Os animais foram divididos em quatro grupos, sendo eles: ordenha mecânica exclusiva (OME; cordeiros apartados 3 dias após o parto), manejo misto com ordenha mecânica (MMom; cordeiros permanecem com as mães durante o período diurno, após a ordenha mecânica, sendo apartados durante a noite), manejo misto com ordenha manual (MMoma) e amamentação exclusiva (AE; cordeiros apartados durante o período noturno). Para a obtenção de LCR foram realizadas a punção do espaço subaracnóideo e implantação de um cateter epidural, enquanto que o plasma foi colhido com o auxílio de um scalp. As amostras de LCR e sangue foram coletadas simultaneamente antes (-0,5 min), durante (0,5; 1 e 4 min) e após (10; 15 min) a amamentação ou ordenha para posterior quantificação das concentrações de ocitocina por ensaio imunoenzimático. Foi obtido um total de 503 amostras, sendo 241 de LCR e 262 de plasma. As estimativas de média, desvio padrão, coeficiente de variação, mínimo e máximo para as concentrações de ocitocina no LCR e plasmáticas foram 257,880 ± 265,90 pg/ml; 103,11%; 11,70 pg/ml e 1000,00 pg/ml, respectivamente. A análise estatística não revelou correlação significante entre LCR e plasma para os quatros grupos experimentais avaliados. O coeficiente de correlação para os grupos OME, AE, MMom e MMoma foram, respectivamente: -0,26, -0,19, 0,05 e 0,04. Com relação ao LCR, não ocorreu diferença significante entre os 4 grupos experimentais em relação às concentrações de ocitocina. Já para o plasma, os animais do grupo MMom (679,80 ± 25,63) e MMoma (591,82 ± 30,56) apresentaram maiores concentrações plasmáticas médias de ocitocina em relação a OME e AE. Assim também, o grupo OME (381,04 ± 22,09) apresentou maior concentração média de ocitocina em relação ao grupo AE (218,82 ± 27,04). Conclui-se que, não existe correlação positiva entre as concentrações de ocitocina central e na circulação periférica durante a ordenha ou amamentação. Os padrões de liberação de ocitocina plasmática diferem de acordo com o tipo de manejo ao qual o animal é submetido, o que pode ter conseqüências para a ejeção do leite e conseqüentemente, para a produção. Finalmente, as concentrações de ocitocina presentes no LCR não sofrem influência do tipo de manejo de ordenha ao qual o animal foi submetido, ao contrário daquilo que foi observado para o plasma. / The aim of the present work was to study a possible relationship between central and peripheral oxytocin release and its consequences to milk production during milking in experimental ewes. Ten multiparous Santa Ines ewes (Ovis aries) were divided in 4 groups according to milk ejection stimuli: exclusive machine milking (OME), mixedmanagement of milking and suckling (MMom: lambs separated during night and reunited to their mother after morning milking; MMoma: mixed-management with manual milking) and exclusive suckling (AE: lambs separated also during night). Cerebrospinal fluid (CSF) was collected through a implanted sub-arachnoid catheter and plasma was collected from the jugular vein. imultaneous sampling was performed at -0.5, 0.5, 1, 4, 10 and 15 min (0 min was teat attachment to either machine or manual milking system or lamb suckling). A total of 241 samples of CSF and 262 plasma samples were processed and oxytocin concentrations were quantified by immunoenzimatic assays. Estimated means, standard deviation, variation coefficient and minimum and maximun values of CSF and plasma oxytocin concentrations were, respectively: 257.880 ± 265.90 pg/ml; 103.11%; 11.70 pg/ml e 1000.00 pg/ml. No statistical strong positive correlations (OME= -0.26, AE= -0.19, MMom= 0.05 and MMoma= 0.04) were found between CSF and plasma samples. Also, CSF was not influenced by milk ejection stimuli, although plasmatic oxytocin was higher in MMom (679.80 ± 25.63) and MMoma (591.82 ± 30.56) compared to OME and AE. In addition, OME (381.04 ± 22.09) plasmatic oxytocin concentration was higher when compared to AE (218.82 ± 27.04). In conclusion, no positive correlations between central and peripheral oxytocin concentrations were observed during milking or suckling. Plasma oxytocin oncentrations differ as a function of management and have consequences to milk ejection as well as to milk production Also, plasma, but not CSF oxytocin, was influenced by different milk ejection stimuli.
4

Ultrasound imaging of anatomy and milk ejection in the human lactating breast

Ramsay, Donna T. January 2005 (has links)
[Truncated abstract] In women, as in other mammals, the ability to successfully lactate depends on both complete functional development of the mammary gland and the stimulation of the milk ejection reflex to enable the suckling young to remove stored milk. Prior to my studies, Sir Astley Cooper’s carried out the most comprehensive investigation of the gross anatomy of the lactating human breast in 1840. I have used ultrasound to image the anatomy of the breasts of fully breastfeeding women (1-6 months, n=22) with particular emphasis on the distribution of the main milk ducts, glandular and adipose tissue. Scanning of the milk duct system demonstrated that the anatomy in the region of the areola and nipple is different to that depicted in standard anatomical textbooks. The main milk ducts were small (diameter, left: 1.9 ± 0.6 mm; right: 2.1 ± 0.7 mm), superficial (depth, left: 4.50 ± 1.98 mm; right: 4.74 ± 1.59 mm) and branched close to the nipple (within 8.20 ± 6.27 mm, left; 7.00 ± 3.98 mm, right) (mean ± SD). The lactiferous sinuses (described in current textbooks) were not observed and the number of main ducts detected at the base of the nipple was less than the quoted 15-20 (9.4, range 4-18). Quantitative descriptions of the morphology of either the lactating or, indeed, the non-lactating breasts have not been attempted using ultrasound. I developed a systematic approach to ultrasound imaging of the breast that provided a semi-quantitative description of the distribution of glandular and adipose tissues within the lactating breast. Approximately two thirds of the breast was comprised of glandular tissue. Intraglandular fat was identified as hypoechoic transects within the hyperechoic glandular tissue. Over 65% of the glandular tissue together with 50% of the intraglandular fat and 25% of the subcutaneous fat was located within a 30 mm radius of the base of the nipple. The absence of lactiferous sinuses and the arrangement of tissue within a 30 mm radius of the nipple suggested that the current conceptualisation of sucking dynamics of the infant requires revision. Successful milk removal depends on the stimulation of the milk ejection reflex and currently subjective assessments of milk ejection such as the mother’s sensations and an alteration in the infants sucking and swallowing are used clinically to confirm milk ejection whereas in research two stressful invasive procedures; changes blood oxytocin and intra-ductal pressure have been used. I have developed a non-invasive ultrasound technique to detect milk ejection in women
5

Ocitocina na Produção e Composição do Leite / Oxytocin on Milk Production and Composition

Mesquita, Alan Andrade 20 June 2012 (has links)
Made available in DSpace on 2016-05-02T13:54:22Z (GMT). No. of bitstreams: 1 AlanAndradeMesquita-dissertacao.pdf: 164106 bytes, checksum: 3b73915b95c788017b359efc06ba110b (MD5) Previous issue date: 2012-06-20 / The objective of this study was to evaluate whether oxytocin, before and after milking, influences the efficiency of milk ejection, and consequently increased production and changes in milk composition. The experiment was conducted at the Federal Institute of Education, Science and Technology in Southern Minas Gerais - Machado Campus in the cattle industry, using 39 animals, divided into 13 blocks, each with three animals listed from "1" to "13". The division of animals was based on the sequence of individual production, so that block "1" was composed by the three most productive animals and block "13" by three animals of lower production. For each block, the animals were randomly assigned to treatments 1, 2 and 3. One (T1) animal did not receive oxytocin, representing the control treatment. It received only normal saline 0.5 ml, in the entire teat during the 60 days of the experiment. In two treatment (T2), all the animals received milking oxytocin at a concentration of 10 IU, total 0.5 ml, before the start of milking, during the 60 days period. In treatment three (T3), the animals received oxytocin at the end of milking at a concentration of 10 IU, total of 0.5ml, and were milked again. Such activities were performed during the 60 days of the experiment. To measure the production of cow s milk meters were used and sampling was performed every 15 days, totaling four weighing and sampling procedures. After measured the production of all animals were, measured samples were collected and sent for analysis. The variables analyzed were the acidity of the milk and quantified of the composition of fat, lactose and protein. The results were submitted to ANOVA and subsequently the comparison of means test, which was statistically significant at 5%. According to the results oxytocin did not influence milk production, the average percentage of fat, lactose and milk protein, but enabled moderation of declining production in the lactation curve and may decrease the effect of the fall in the percentage of protein in milk. / O objetivo deste trabalho foi avaliar se a ocitocina, antes e após a ordenha, influencia a eficiência da ejeção do leite e consequentemente o aumento da produção e mudanças na composição do leite. O experimento foi realizado no Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais - Câmpus Machado, no setor de bovinocultura, utilizando 39 animais, divididos em 13 blocos, cada um com três animais enumerados de 1 a 13 , e foi utilizado na divisão dos animais, uma sequência de produção individual. Assim, o bloco 1 foi composto pelos três animais mais produtivos, e o bloco 13 , pelos três animais de menor produção. Em cada bloco os animais foram sorteados para os tratamentos 1, 2 e 3, sendo que no tratamento um (T1) os animais não receberam ocitocina, representando o tratamento controle, apenas recebendo 0,5ml de soro fisiológico, em todas as ordenhas, durante os 60 dias do experimento. No tratamento dois (T2) os animais receberam ocitocina em todas as ordenhas, na concentração de 10 UI, no total de 0,5 ml, antes do início da ordenha, durante os 60 dias do experimento. No tratamento três (T3) os animais, receberam ocitocina no final de ordenha, na concentração de 10 UI, no total de 0,5 ml e foram reordenhados, atividades essas realizadas durante os 60 dias do experimento. Para aferir a produção das vacas, foram usados medidores de leite, e as colheitas de amostras foram realizadas a cada 15 dias, totalizando quatro procedimentos de pesar e amostrar. Após aferido a produção de todos os animais, as amostras foram coletadas e encaminhadas para as análises. As variáveis analisadas foram a acidez do leite, e após a determinação da acidez, quantificou-se a composição de gordura, lactose e proteína. Os resultados foram submetidos à análise de variância e posteriormente, ao teste de comparação de médias, com diferença estatística significativa de 5%. De acordo com os resultados, a ocitocina não influência a produção leiteira, nas médias de porcentagem de gordura, lactose e proteína do leite, mas possibilita a moderação da queda de produção na curva de lactação e pode diminuir o efeito da queda da porcentagem de proteína na lactação.
6

Dieta hiperlipídica materna: influências sobre o comportamento maternal e o desenvolvimento da prole. / Maternal high fat diet: influences on maternal behavior and offspring development.

Klein, Marianne Orlandini 22 July 2016 (has links)
Uma nutrição maternal rica em lipídios pode causar prejuízos no desenvolvimento e na vida adulta dos descendentes, como elevado risco de desenvolver alterações metabólicas e obesidade, e também parece alterar a sinalização central por opióides. Porém, estudos realizados a fim de investigar a influência da dieta hiperlipídica (HF) materna sobre o comportamento materno e o desenvolvimento da prole não são conclusivos. Este trabalho investigou a influência da dieta HF sobre a interação mãe-filhote, em duas gerações, e os efeitos imediatos e tardios sobre a prole, relacionando-os ao sistema opióide. As mães HF apresentaram prejuízos na ejeção do leite e maior expressão dos receptores opióides no hipotálamo. No geral, os descendentes HF apresentaram elevados níveis de colesterol, baixa leptina plasmática, maior expressão de peptídeos relacionados à ingestão alimentar, e menor peso. Portanto, o consumo materno de dieta HF causou alterações metabólicas, comportamentais e na expressão gênica na mãe e nos descendentes, mesmo que esses animais não tenham se tornado obesos. / A maternal nutrition high in fat may impair offspring development and adulthood, increasing the risk to develop metabolic alterations and obesity, and may modify the opioids central signaling. However, studies investigating maternal high fat (HF) diet influences on maternal behavior and offspring development are inconclusive. This study aimed to evaluate the influences of a diet high in fat on mother-pup interaction, in two generations, and its early and late effects in the offspring, connecting them to the opioid system. HF dams show decreased milk ejections and higher expression of opioid receptors in the hypothalamus. Overall, HF offspring had higher cholesterol levels, less serum leptin, higher expression of peptides related to food intake, and were lighter. Therefore, maternal intake of HF diet promoted metabolic, behavioral and gene expression alterations in the mother and her offspring, even though these animals did not become obese.
7

Dieta hiperlipídica materna: influências sobre o comportamento maternal e o desenvolvimento da prole. / Maternal high fat diet: influences on maternal behavior and offspring development.

Marianne Orlandini Klein 22 July 2016 (has links)
Uma nutrição maternal rica em lipídios pode causar prejuízos no desenvolvimento e na vida adulta dos descendentes, como elevado risco de desenvolver alterações metabólicas e obesidade, e também parece alterar a sinalização central por opióides. Porém, estudos realizados a fim de investigar a influência da dieta hiperlipídica (HF) materna sobre o comportamento materno e o desenvolvimento da prole não são conclusivos. Este trabalho investigou a influência da dieta HF sobre a interação mãe-filhote, em duas gerações, e os efeitos imediatos e tardios sobre a prole, relacionando-os ao sistema opióide. As mães HF apresentaram prejuízos na ejeção do leite e maior expressão dos receptores opióides no hipotálamo. No geral, os descendentes HF apresentaram elevados níveis de colesterol, baixa leptina plasmática, maior expressão de peptídeos relacionados à ingestão alimentar, e menor peso. Portanto, o consumo materno de dieta HF causou alterações metabólicas, comportamentais e na expressão gênica na mãe e nos descendentes, mesmo que esses animais não tenham se tornado obesos. / A maternal nutrition high in fat may impair offspring development and adulthood, increasing the risk to develop metabolic alterations and obesity, and may modify the opioids central signaling. However, studies investigating maternal high fat (HF) diet influences on maternal behavior and offspring development are inconclusive. This study aimed to evaluate the influences of a diet high in fat on mother-pup interaction, in two generations, and its early and late effects in the offspring, connecting them to the opioid system. HF dams show decreased milk ejections and higher expression of opioid receptors in the hypothalamus. Overall, HF offspring had higher cholesterol levels, less serum leptin, higher expression of peptides related to food intake, and were lighter. Therefore, maternal intake of HF diet promoted metabolic, behavioral and gene expression alterations in the mother and her offspring, even though these animals did not become obese.
8

Mödrars upplevelser och erfarenheter av amningsångest och dysforisk mjölkutdrivningsreflex : En analys av inlägg på internet / Mothers´ experiences of breastfeeding anxiety and dysphoric milk ejection reflex : An analysis of posts on the internet

Sundkvist, Elin January 2023 (has links)
Att få barn är en stor livsstilsförändring som kan komma med många utmaningar. Att amma sitt barn anses ofta som en självklarhet och det talas om amningens många fördelar. Däremot talas det sällan om svårigheter som kan uppkomma i samband med amning. Amningsångest och dysforisk mjölkutdrivningsreflex är ett relativt okänt tillstånd vilket kan leda till onödigt lidande för de ammande mödrarna. Syftet med studien var att beskriva mödrars upplevelser och erfarenheter av amningsångest och dysforisk mjölkutdrivningsreflex. Det är en kvalitativ studie med induktiv ansats. Data samlades in genom blogginlägg, kommentarer och publicerade intervjuer där mödrar beskrivit sina upplevelser. Insamlad data analyserades med en kvalitativ innehållsanalys som resulterade i två kategorier: Okunskap om amningssvårigheter hos ammande mödrar och Okunskap om amningssvårigheter hos vårdpersonal. Kategorierna bildade temat: Mödrars behov av förståelse, bekräftelse och hjälp i den postnatala vården. Utifrån denna studie kan vårdpersonal som möter ammande mödrar få förståelse för och kunskap om hur mödrar upplever sin amningsångest och dysforiska mjölkutdrivningsreflex, och även att mödrarna själva kan få kunskap om att det är ett tillstånd som existerar. Studien kan ligga till grund för kunskapsspridning om amningsångest och dysforisk mjölkutdrivningsreflex och resultera i att mödrar upplever mindre ensamhet och lidande. / Having a baby is a lifestyle change that can come with challenges. Breastfeeding is often taken for granted and the many benefits are often talked about. However, it rarely talks about difficulties that can arise. Breastfeeding anxiety and dysphoric milk ejection reflex is a relatively unknown condition which can lead to unnecessary suffering for breastfeeding mothers. The purpose of the study was to describe mothers' experiences of breastfeeding anxiety and dysphoric milk ejection reflex. It is a qualitative study with an inductive approach. Data was collected through blogposts, comments and published interviews where mothers described their experiences. Data were analyzed with a qualitative analysis that resulted in two categories: Ignorance of breastfeeding difficulties in nursing mothers and Ignorance of breastfeeding difficulties in healthcare personnel. The categories formed the theme: Mothers' need for understanding, confirmation and help in postnatal care. Based on this study, healthcare professionals can gain understanding and knowledge of how mothers experience their breastfeeding anxiety and dysphoric milk ejection reflex, but also the mothers themselves gain knowledge that it is a condition that exists. The study can spread knowledge about breastfeeding anxiety and dysphoric milk drive reflex, which can result in mothers experiencing less loneliness and suffering.
9

Untersuchungen zu Milchejektionsstörungen bei erstlaktierenden Kühen

Heidig, Katrin 30 July 2007 (has links)
Die vorliegende Arbeit hatte zum Ziel, das Auftreten von Milchejektionsstörungen in Produktionsherden zu erfassen und deren Ursachen zu finden. Die Fragestellung wurde in fünf methodisch sehr unterschiedlichen Untersuchungsblöcken bearbeitet, die tierindividuelle Aufzeichnungen zu Kalbung und Verlauf des Einmelkens, Verhaltensbeobachtungen im Vorabkalbezeitraum und Messungen psychophysiologischer Parameter (Herzfrequenz, Elektromyogramm, Hautpotential und Hautwiderstand) während eines Tests auf Stressstabilität sowie während des Einmelkens beinhalteten. Es nahmen 9 sächsische Betriebe an der Untersuchung teil. Die Datenerfassung erfolgte über einen Zeitraum von 20 Monaten in den Jahren 2004 / 2005. Es konnten die Daten von 1767 Färsen erfasst werden. Es wurden eindeutige Zusammenhänge zwischen dem durch suboptimale Haltungsbedingungen verursachten Wirken sozialer Stressoren in der Tiergruppe und dem Auftreten von MES gefunden. Demnach trat MES verstärkt in Betrieben auf, in denen bereits im Vorfeld der Kalbung eine chronische Stresssituation für die Tiere bestand. Hierbei konnten bei gemischten Färsen – Kuh- Gruppen die Anwesenheit der Altkühe und bei reinen Färsengruppen das zu geringe Platzangebot im Laufbereich als Hauptursache gefunden werden. Die Umstände von Abkalbung und Einmelken sind in den untersuchten Betrieben nicht primäre Ursache von MES, können aber verstärkend oder mildernd wirken. So bewirken Umstallungen kurz vor dem Abkalbetermin, eine langer Verbleib des Kalbes an der Kuh, zu kurze Pausen zwischen der Kalbung und der ersten Melkung sowie gesundheitliche Beschwerden im peripartalen Zeitraum ein Ansteigen des MES-Risikos. Betroffen sind hierbei vor allem stresslabile und rangniedrige Tiere sowie Tiere, die unter Testbedingungen bevorzugt introvertierte Verhaltensweisen (ängstlich, demütig) zeigten. Es bestand kein Unterschied hinsichtlich der Stressstabilität der Herden zwischen den Betrieben. Während des Einmelkens unterschieden sich Tiere mit und ohne MES in ihrem Verhalten und den gemessenen Parametern kaum von einander. Tiere mit MES zeigen lediglich eine verstärkte Neigung zu Überreaktionen und eingeschränkter Reaktionsfähigkeit bei den elektrodermalen Parametern, wobei die Differenzen häufig nicht statistisch zu sichern waren. Es konnte keine genetische Veranlagung zur Ausbildung einer MES nachgewiesen werden. Die errechnete Heritabilität lag bei h² = 0,009. MES ist somit als ein betriebsspezifisches Problem zu bezeichnen, das in den hier untersuchten Betrieben vor allem haltungsbedingte Ursachen hat. / The present study was designed to describe the occurrence and determine the causes of disturbed milk ejection (= MES = Milchejektionsstörung) in production herds. The question was treated in an examination with five parts with difficult methods: record individually courses of calving and the first milkings, observe the behaviour in the last weeks before the calving, measure psychophysiological parameters (heartrate, elektromyogram, skin conduction and electrical skin resistance) during a test of stress sensitivity and during the first milkings and an genetic analysis. Nine saxonian herds were involved. The data record was for 20 months in the years 2004 / 2005 and cover 1767 heifers. We found clear connections between social strains, they work in the groups of animals and was caused through suboptimal environment, and the occurrence of MES. We found more MES in herds, where animals had a chronical stress situation in the last weeks bevor the calving. The most important stressors are the presence of multiparous cows in mixed groups with cows and heifers and the lack of room for motion in the box when heifers are alone. The circumstances of calving and the first milkings are not the primary causes of MES in this study, but they can influence this problem. So we found an increase of risk for MES, when 1. the time between the transport of animals in the calving box and the calving was too short, 2. the calf stayed with the cow, 3. the time between the calving and the first milking was too short 4. the animal has health problems in the time around the calving. The animals with the highest risk for MES have low stress resistance are unstable for stress, have a low range in the herd and showed an introverted behaviour (timid, humble) in the test. There was no difference in the stress sensitivity between the herds. During the first milkings we found just little differents at behaviour and at measured parameters between animals with and without MES. Animals with MES showed a small disposition to overreactions or to restrict the ability of reaction in elektrodermal parameters, but the differences are often not significant. We couldn´t found genetic causes of MES. The heritability was h² = 0,009. In conclusion, MES is an herd specific problem. In the herds that were examine, the important causes of MES are suboptimale environment and management of the groups of animals.

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