959 resultados para HOLSTEIN HEIFERS


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La fotosensibilización hepatógena se estudia por los servicios veterinarios desde el siglo pasado, estableciéndose una de las causales de ésta enfermedad la Lantana camara (verbena morada), donde los animales presentaban hemorragias y dermatitis, no reportándose la presencia de plantas fotosensibilizadoras, ni dermatitis ocasionada por otra causa según los resultados laboratoriales, sólo la evidencia del consumo junto al forraje de la planta Ageratum houstonianum Mill. El objetivo de este trabajo es evaluar algunos efectos tóxicos de las plantas A. houstonianum y L. camara en terneros y se realizó a partir de la formación de dos grupos de animales (terneros) intoxicados experimentalmente con A. houstonianum y L. camara basado en las regulaciones de bienestar animal para los casos estudiados. Se estudiaron aspectos relacionados con la triada, tiempo de sangramiento y de coagulación en los que hubo evidencias de alteración para los parámetros fisiológicos de la especie en los animales tratados. Los análisis estadísticos se basaron en t student y regresión lineal.

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To be able to carry out physical, chemical and biological investigations on a lake, one needs a thorough knowledge of the volume of water and the shape of the lake basin. Little is known about the about the morphology of the lakes in Schleswig-Holstein and its ecological consequences. For this research a 30 KHz echo sounder with sediment transceiver was used to carry out profile determinations (echo soundings). This apparatus continuously records on paper the different reflexions and absorptions of the sediment and water body in the corresponding depth. By this, acoustically noticeable layers and different densities in the sediment and 'scattering layers' in the water body due to physical, chemical and biological reasons (e.g. plans and single fish) are made visible. Result are summarised here regarding the echo soundings in Blunker See.

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In vitro fertilization (IVF) is a feasible way to utilize sex-sorted sperm to produce offspring of a predetermined sex in the livestock industry. The objective of the present study was to examine the effects of various factors on bovine IVF and to systema

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Using heterogeneous vegetation in alpine grassland through grazing is a necessary component of deintensification of livestock systems and conservation of natural environments. However, better understanding of the dynamics of animal feeding behaviour would improve pasture and livestock grazing managements, particularly in the early part of the spring season when forage is scarce. The changes in behaviour may improve the use of poor pastures. Then, enhancing management practices may conserve pasture and improve animal productivity. Grazing behaviour over 24 In periods by yaks in different physiological states (lactating, dry and replacement heifers) was recorded in the early, dry and later, germinating period of the spring season. Under conditions of inadequate forage, the physiological state of yaks was not the primary factor affecting their grazing and ruminating behaviour. Forage and sward state affected yaks' grazing and ruminating behaviour to a greater extent. Generally, yaks had higher intake and spent more time grazing and ruminating during the later part of the spring season, following germination of forage, than during the earlier dry part of the season. However, the live weight of yaks was less during pasture germination than during the early dry part of the season because the herbage mass is low, and the yaks have to expend much energy to seek feed at this particular time. (c) 2007 Elsevier B.V. All rights reserved.

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Las evaluaciones genéticas para caracteres funcionales requieren metodologías como el análisis de supervivencia (SA), que contemplen registros pertenecientes a hembras que no han presentado el evento de interes (descarte o prenez) al momento de la evaluacion. Así, los objetivos de esta tesis fueron: 1) analizar los factores que afectan el riesgo de descarte en vida productiva (VP), y de concepción en días abiertos (DA) e intervalo primer-último servicio (IP), 2) estimar parámetros genéticos de dispersión para los caracteres evaluados. Se emplearon 44652 registros de lactancia de 15706 vacas Holstein Colombiano, ajustando un modelo animal frágil Weibull para VP, con el número de partos (NP), producción de leche (PL) y edad al primer parto (EPP) como efectos fijos. En el caso de DA e IPU se emplearon 14789 servicios de 6205 vacas, ajustando un modelo de datos agrupados con efectos fijos de NP, EPP y número de servicios (SC). En todos los casos se incluyeron efectos aleatorios de animal y de hato. Tanto PL como NP tuvieron gran influencia en la VP, al igual que NP en DA e IPU. Se estimaron valores de h2 de 0,104, 0,086 y 0,1013 para VP, DA, e IPU, respectivamente, asi como correlaciones genéticas simples (rs) entre el nivel de PL con VP y DA de ƒ{0,03 y 0,47, respectivamente. Teniendo en cuenta tanto los valores de cría expresados como riesgo relativo, asi como la magnitud de rs, un aumento en PL conllevaría a disminución en el riesgo de descarte y aumento en el riesgo de concepción, dando lugar a aumentos en la VP y reducción en DA. Las h2s estimadas sugieren la existencia de variabilidad genetica para VP, DA e IPU en Holstein Colombiano, sirviendo de sustento para la implementación de evaluaciones genética de la raza, aprovechando las ventajas de metodologías como SA.

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Las evaluaciones genéticas para caracteres funcionales requieren metodologías como el análisis de supervivencia (SA), que contemplen registros pertenecientes a hembras que no han presentado el evento de interes (descarte o prenez)al momento de la evaluacion. Así, los objetivos de esta tesis fueron: 1)analizar los factores que afectan el riesgo de descarte en vida productiva (VP), y de concepción en días abiertos (DA)e intervalo primer-último servicio (IP), 2)estimar parámetros genéticos de dispersión para los caracteres evaluados. Se emplearon 44652 registros de lactancia de 15706 vacas Holstein Colombiano, ajustando un modelo animal frágil Weibull para VP, con el número de partos (NP), producción de leche (PL)y edad al primer parto (EPP)como efectos fijos. En el caso de DA e IPU se emplearon 14789 servicios de 6205 vacas, ajustando un modelo de datos agrupados con efectos fijos de NP, EPP y número de servicios (SC). En todos los casos se incluyeron efectos aleatorios de animal y de hato. Tanto PL como NP tuvieron gran influencia en la VP, al igual que NP en DA e IPU. Se estimaron valores de h2 de 0,104, 0,086 y 0,1013 para VP, DA, e IPU, respectivamente, asi como correlaciones genéticas simples (rs)entre el nivel de PL con VP y DA de ƒ{0,03 y 0,47, respectivamente. Teniendo en cuenta tanto los valores de cría expresados como riesgo relativo, asi como la magnitud de rs, un aumento en PL conllevaría a disminución en el riesgo de descarte y aumento en el riesgo de concepción, dando lugar a aumentos en la VP y reducción en DA. Las h2s estimadas sugieren la existencia de variabilidad genetica para VP, DA e IPU en Holstein Colombiano, sirviendo de sustento para la implementación de evaluaciones genética de la raza, aprovechando las ventajas de metodologías como SA.

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The aim of the present study was to assess the effects of Holstein-Friesian (HF) and Norwegian (N) dairy cattle genotypes on lameness parameters in dairy cattle within different production systems over the first 2 lactations. Following calving, HF (n = 39) and N (n = 45) heifers were allocated to 1 of 3 systems of production (high level of concentrate, low level of concentrate, and grass-based). High-and low-concentrate animals were continuously housed indoors on a rotational system so that they spent similar amounts of time on slatted and solid concrete floors. Animals on the grass treatment grazed from spring to autumn in both years of the study, so that most animals on this treatment grazed from around peak to late lactation. Claw health was recorded in both hind claws of each animal at 4 observation periods during each lactation as follows: 1) -8 to 70 d postcalving, 2) 71 to 150 d postcalving, 3) 151 to 225 d postcalving, and 4) 226 to 364 d postcalving. Sole lesions, heel erosion, axial wall deviation, sole length of the right lateral hind claw (claw length), right heel width, and right lateral hind heel height were recorded as well as the presence of digital dermatitis. The N cows had lower (better) white line and total lesion scores than HF cows. Cows on the high-and low-concentrate treatments had better sole and total lesion scores than cows on the grass treatment. The HF cows had better locomotion scores than N cows. Breed and production system differences were observed with respect to claw conformation, including claw length, heel width, and heel height. Digital dermatitis was associated with worse sole lesion scores and interacted with production system to influence white line lesion scores and maximum heel erosion scores. This study shows that genetic, environmental, and infectious factors are associated with hoof pathologies in dairy cows.

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Reproductive performance in the high-yielding dairy cow has severely decreased in the last 40 yr. The aim of this study was to compare the effectiveness of 4 nutritional strategies in improving the reproductive performance of high-yielding dairy cows. It was hypothesized that offering cows a high-starch ration in early lactation would enhance the onset of luteal activity, and that decreasing the severity of negative energy balance in the early postcalving period would improve reproductive parameters. Nutritional regimens aimed at improving fertility were applied to 96 Holstein-Friesian dairy animals. Upon calving, animals were allocated in a balanced manner to one of 4 dietary treatments. Primiparous animals were balanced according to live weight, body condition score and calving date. Multiparous animals were balanced according to parity, previous lactation milk yield, liveweight, body condition score and calving date. Treatment 1 was based on an industry best practice diet (control) to contain 170 g of crude protein/kg of dry matter. Treatment 2 was an individual cow feeding strategy, whereby the energy balance (EB) of individual animals was managed so as to achieve a predetermined target daily EB profile (+/- 10 MJ/d). Treatment 3 was a high-starch/high-fat combination treatment, whereby an insulinogenic (high-starch) diet was offered in early lactation to encourage cyclicity and followed by a lipogenic (low-starch, high-fat) diet to promote embryo development. Treatment 4 was a low-protein diet, containing 140 g of crude protein/kg of dry matter, supplemented with protected methionine at an inclusion level of 40 g per animal per day. The nutritional strategies implemented in this study had no statistically significant effects on cow fertility measures, which included the onset of luteal activity, conception rate, in-calf rate, and the incidence of atypical cycles. The individual cow feeding strategy improved EB in early lactation but had no benefit on conception rate to first insemination. However, conception rate to second insemination, 100-d pregnancy rate (from the commencement of breeding), and overall pregnancy rate tended to be higher in this group. The high-starch/high-fat treatment tended to decrease the proportion of delayed ovulations and increase the proportion of animals cycling by d 50 postcalving. Animals that failed to conceive to first insemination had a significantly longer luteal phase in the first cycle postpartum and a longer inter-ovulatory interval in the second cycle postpartum. With regards to estrous behavior, results indicate that as the size of the sexually active group increased, the intensity of estrus and the expression of mounting or attempting to mount another cow also increased. Furthermore, cows that became pregnant displayed more intense estrous behavior than cows that failed to become pregnant.

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Although interest in crossbreeding within dairy systems has increased, the role of Jersey crossbred cows within high concentrate input systems has received little attention. This experiment was designed to examine the performance of Holstein-Friesian (HF) and Jersey x Holstein-Friesian (J x HF) cows within a high concentrate input total confinement system (CON) and a medium concentrate input grazing system (GRZ). Eighty spring-calving dairy cows were used in a 2 (cow genotype) x 2 (milk production system) factorial design experiment. The experiment commenced when cows calved and encompassed a full lactation. With GRZ, cows were offered diets containing grass silage and concentrates [70:30 dry matter (DM) ratio] until turnout, grazed grass plus 1.0 kg of concentrate/day during a 199-d grazing period, and grass silage and concentrates (75:25 DM ratio) following rehousing and until drying-off. With CON, cows were confined throughout the lactation and offered diets containing grass silage and concentrates (DM ratio; 40:60, 50:50, 40:40, and 75:25 during d 1 to 100, 101 to 200, 201 to 250, and 251 until drying-off, respectively). Full-lactation concentrate DM intakes were 791 and 2,905 kg/cow for systems GRZ and CON, respectively. Although HF cows had a higher lactation milk yield than J x HF cows, the latter produced milk with a higher fat and protein content, so that solids-corrected milk yield (SCM) was unaffected by genotype. Somatic cell score was higher with the J x HF cows. Throughout lactation, HF cows were on average 37 kg heavier than J x HF cows, whereas the J x HF cows had a higher body condition score. Within each system, food intake did not differ between genotypes, whereas full-lactation yields of milk, fat plus protein, and SCM were higher with CON than with GRZ. A significant genotype x environment interaction was observed for milk yield, and a trend was found for an interaction with SCM. Crossbred cows on CON gained more body condition than HF cows, and overall pregnancy rate was unaffected by either genotype or management system. In summary, milk and SCM yields were higher with CON than with GRZ, whereas genotype had no effect on SCM. However, HF cows exhibited a greater milk yield response and a trend toward a greater SCM yield response with increasing concentrate levels compared with the crossbred cows.

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The relationship between lameness and feeding behaviour in dairy cows is not yet fully understood. This study examined the effect of lameness on feeding behaviour at two points during lactation. Forty-five Holstein–Friesian dairy cows (average parity 3.3) were housed in cubicle accommodation after calving and fed a total mixed ration (TMR). At approximately 60 and 120 days post partum, 48 h of information on feeding behaviour (including number of meals eaten, meal duration, meal size and feeding rate) was collected for each animal using feed boxes fitted to a data recording system. At the same time points, locomotion scores were recorded for each cow as a measure of lameness (1.0-sound to 4.5-severely lame). Relationships between feeding behaviour and locomotion score were analysed using Residual Maximum Likelihood (REML) analysis. At both time points, cows with higher locomotion scores ate fewer (P < 0.001), larger meals (P < 0.001) and had a shorter total feeding time (P < 0.001). At day 60 post partum, an increase in locomotion score was associated with a decrease in dry matter intake (P < 0.05), but at day 120 post partum no relationship was found between locomotion score and DMI. No relationship was found at either time point between locomotion score and mean meal duration or rate of feeding. The results of this study suggest that the effect of lameness on feeding behaviour in dairy cows does not remain constant across lactation.

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Neste trabalho definimos e desenvolvemos algumas ideias centrais sobre a Galeria Nacional de Pintura da Academia de Belas Artes de Lisboa, da formação do seu acervo a partir de 1834, com a extinção das ordens religiosas, até à abertura do Museu Nacional de Belas Artes e Arqueologia, em 1884. Em análise estão 50 anos de esforços empreendidos por vários agentes, com destaque para o marquês de Sousa Holstein, vice-­‐inspetor da Academia, em prol da organização, conservação, exposição, estudo, promoção e divulgação do seu acervo, assim como do seu enriquecimento por meio de transferências, aquisições ou doações que estão na origem do mais relevante museu público de arte nacional.

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Référence bibliographique : Rol, 60571