Made available in DSpace on 2016-06-02T20:20:26Z (GMT). No. of bitstreams: 1 TeseTBM.pdf: 401834 bytes, checksum: fba52ede0a39e98b173078af1f5a85d5 (MD5) Previous issue date: 2006-10-20 / Financiadora de Estudos e Projetos / The objective in this study was to estimate genetic parameters for the traits days to calving (DC), days to first calving (DFC) and gestation length (GL), associated with reproductive performance of females, as well as to evaluate the relationships of DC and DFC with scrotal circumference at 12 months of age (SC12) and body weights at 12 months of age (W12), at calving (WC), at first calving (WFC), at beginning of the breeding season (WBS) and at beginning of the first breeding season (WFBS), and of GL with weight at birth (BW) and W12. Analyses were done using animal models and the derivative free restricted maximum likelihood methodology. Estimates of heritabilities varied from 0.02 to 0.09 for DC, from 0.15 to 0.23 for DFC and from 0.04 to 0.41 for GL, depending on the data set and the model used for each trait. Genetic correlations of DC and DFC with SC12 showed that it is possible to improve these female reproductive traits by selecting for increase in SC12. With respect to W12, selection to increase this trait should not produce significant changes in DC, but may increase DFC. Associations of the other female body weights with DFC and DC indicated that heavier females experience lower reproductive performance. Estimates of genetic correlations of GL with BW and W12 indicated that selection to change GL will result in correlated response in BW with no changes in W12. / O objetivo neste estudo foi estimar parâmetros genéticos para as características dias para o parto (DP), dias para o primeiro parto (DPP) e período de gestação (PG), associadas ao desempenho reprodutivo de fêmeas, bem como avaliar as relações de DP e DPP com o perímetro escrotal aos 12 meses de idade (PE12) e os pesos aos 12 meses de idade de machos e fêmeas (P12), ao parto (PVP), ao primeiro parto (PVPP), à entrada da estação de monta (PEM) e à entrada da primeira estação de monta (PEPM), e do PG com o peso do bezerro ao nascimento (PN) e com P12. As análises foram realizadas utilizando modelos animais e o método da máxima verossimilhança restrita livre de derivadas. As estimativas de herdabilidade variaram de 0,02 a 0,09 para DP, de 0,15 a 0,23 para DPP e de 0,04 a 0,41 para PG, dependendo do arquivo e do modelo utilizados para cada característica. As correlações genéticas de DP e DPP com PE12 mostraram que é possível obter melhoria das características reprodutivas de fêmeas selecionando-se para aumento de PE12. Com relação a P12, a seleção para aumentar essa característica não deve gerar resposta significativa em DP, mas pode aumentar DPP. A avaliação das associações dos demais pesos de fêmeas com DPP e DP indicou que fêmeas maiores apresentam pior desempenho reprodutivo. As correlações genéticas do PG com PN e com P12 mostraram que a utilização de PG como critério de seleção resulta em resposta correlacionada em PN sem alterar P12.

Made available in DSpace on 2016-12-08T16:24:22Z (GMT). No. of bitstreams: 1 PGCA15MA174.pdf: 1125115 bytes, checksum: debf2ea0252ff58d406adab80ac46300 (MD5) Previous issue date: 2015-06-25 / Improvement of animal nutrition and management, together with genetic selection for milk yeld, increased the productivity of the herds, especially Holstein cows. On the other hand, characteristics related to fertility, health and longevity were disadvantaged The aim was to compare the development, milk yeld and composition, the health of the mammary gland, the body condition score (BCS), reproductive performance and longevity of crossbred Holstein x Simmental cows with Holstein cows. To obtain the data set two farms were used, one in Bom Retiro in SC and another in Carambeí in PR. For growth evaluation, weight gain of the animals were evaluated monthly. For production and udder health data from the official Dairy Herds Improvement Programs of the farm were used. BCS and body weight estimation were made on the farm with an interval between 60 and 90 days within one year. Information concerning the date of birth, parity date, date and number of inseminations, were obtained from the management software of the farms, generating information regarding the calving interval, days between calving to first service, conception rate, age at first calving. In one of the farms, calving were monitoring to quantify the calving difficulty, in the same farm, information of culling were obtained to determine the survival rate of cows. Data were analyzed by statistical package of SAS, using the MIXED and GENMOD procedures. For growth curve, production and composition of milk, (BCS) and body weight nonlinear regression was used, using the NLIN procedure of SAS and the curves of Gompertz (growth) and Wood (production and composition) were used because of having the lowest mean square. Holstein x Simmental crossbred cows produced more milk 31,8 x 30,4 kg/day (P < 0,05), with higher content of lactose and protein, with no difference for fat content. Holstein cows had higher somatic cell score (SCS) 4.49 x 2.93 (P <0.0001) compared to crossbreed cows. Holstein x Simmental crossbred cows had better BCS during lactation 3.65 x 2.94 (P <0.0001) with no difference in body weight in relation to Holstein cows. For growth of calves and heifers there was no difference between the genetic groups. Crossbred cows Holstein x Simmental had better reproductive performance than the Holstein cows, characterized by lower calving interval (381 x 445 days), higher conception rate (37.31 x 33, 64%) and shorter interval calving to first service (65.6 x 89.3 days). Crossbred cows Holstein x Simmental had higher survival rate than Holstein cows (83 x 92 In conclusion, crossbred cows Holstein x Simmental produce more milk with higher content of lactose and protein, have less ECS and greater BCS without difference for growing of heifers and body weight in adult age. Crossbred cows still have better reproductive performance and have a higher survival rate than the Holstein cows / Melhorias na nutrição e no manejo dos rebanhos bem como a seleção genética para a produção de leite aumentaram a produtividade dos animais. Em contrapartida, características relacionadas a fertilidade, sanidade e longevidade foram prejudicadas. O objetivo foi comparar o desenvolvimento, a produção e composição do leite, a sanidade da glândula mamária, o escore de condição corporal o desempenho reprodutivo e a longevidade de vacas mestiças Holandês x Simental em relação as vacas puras Holandês. Foram utilizadas duas propriedades, uma localizada no município de Bom Retiro em SC e outra em Carambeí no PR. Para avaliação de crescimento o ganho de peso dos animais foi avaliado mensalmente. Para obter dados produtivos e de sanidade de úbere foram utilizados dados do controle leiteiro oficial da propriedade. As avaliações de escore e peso vivo foram realizadas na propriedade com intervalo entre 60 e 90 dias no período de um ano, informações estas obtidas em uma das propriedades. As informações referentes a data de nascimento, data de parto, data e número de coberturas, foram obtidas junto aos software de gerenciamento de ambas as propriedades, gerando informações referentes ao intervalo entre partos (IEP), período parto primeiro serviço, taxa de concepção, idade ao primeiro parto. Em uma das propriedades foi feito o acompanhamento dos partos para quantificar a dificuldade de parto, da mesma forma, foram obtidas informações referentes ao descarte de animais para determinar a taxa de permanência no rebanho das vacas. Os dados foram analisados pelo pacote estatístico SAS, utilizando-se os procedimentos MIXED e GENMOD Para curva de crescimento, de produção e composição do leite bem como escore de condição corporal (ECC) e peso vivo foi utilizada a técnica de regressão não linear, do pacote estatístico SAS sendo que foram utilizadas as curvas de Gompertz (crescimento) e de Wood (produção e composição) por apresentarem o menor quadrado médio do erro. Vacas mestiças Holandês x Simental produziram mais leite 31,8 x 30,4 ( P < 0,05), com maior teor de lactose e proteína, sem diferença para teor de gordura. Vacas Holandês obtiveram maior escore de células somáticas (ECS) 4,49 x 2,93 (P < 0,0001) em relação as mestiças. Vacas mestiças Holandês x Simental obtiveram melhor ECC durante a lactação 3,65 x 2,94 (P < 0,0001) sem diferença para peso vivo em relação as vacas Holandês. Para crescimento de bezerras e novilhas não houve diferença entre os grupamentos genéticos. Vacas mestiças Holandês x Simental obtiveram melhor desempenho reprodutivo em relação as vacas puras, caracterizado através do menor IEP (381 x 445 dias), maior taxa de concepção (37,31 x 33, 64 %) bem como menor intervalo parto primeiro serviço (65,6 x 89,3 dias). Vacas mestiças Holandês x Simental apresentaram maior taxa de permanência no rebanho em relação as vacas puras (83 x 92 %). Conclui-se que vacas mestiças produzem mais leite, com maior teor de lactose e proteína, possuem menos ECS e maior ECC sem diferença para crescimento de novilhas e peso vivo na idade adulta. Apresentam ainda melhor desempenho reprodutivo e maior taxa de permanência no rebanho em relação as vacas puras Holandês

Future sea level rise associated to global warming is one of the greatest societal and environmental challenges of tomorrow. A large part of the contribution comes from glaciers and ice sheets discharging ice and meltwater into the ocean and the recent worldwide increase is worrying. Future predictions of sea level rise try to encompass the complex processes of ice dynamics through glacier modelling but there are still large uncertainties due to the lack of observations or too coarse parameterisation, particularly for processes occurring at the glacier interfaces with the bed (sliding) and with the ocean (calving). This thesis focuses on modelling these processes from two marine-terminating glaciers in Svalbard, Kronebreen and Tunabreen. By inverting three years of high temporal resolution time-series of surface velocities on Kronebreen, basal properties are retrieved with the ice flow model Elmer/Ice in Paper I. Results suggest that surface melt during the summer greatly influences the dynamics of the following season and that sliding laws for such glaciers should be adapted to local and global processes changing in space and time. The subglacial drainage system, fed by the surface melt, is modelled in Paper II during two melting seasons. Results show different configurations of efficient and inefficient drainage systems between years and the importance of using a sliding law dependent on spatio-temporal changes in effective pressure. The interaction with the ocean is incorporated in Paper III by combining a series of models, including an ice flow model, a plume model and a particle model for discrete calving and compares the output with observations. Results show the importance of glacier geometry, sliding and undercutting on calving rate and location. However, more observations and analytic methods are needed. Time-lapse imagery placed in front of Tunabreen have been deployed and a method of automatic detection for iceberg calving is presented in Paper IV. Results show the influence of the rising plume in calving and the front destabilisation of the local neighbourhood.

Thesis (M.A. Agricultural Management (Animal Production)) -- University of Limpopo, 2020 / The Nguni is indigenous multi-purpose cattle breed that plays an important role in both commercial and communal farming systems in South Africa (SA). Unfortunately, the breed is currently under threat of diminishing due to farmers’ preference for exotic breeds and cross breeding. In recognition of the above, the Industrial Development Corporation, the Mpumalanga Department of Agriculture, Rural Development, Land and Environmental Affairs and the University of Limpopo established the Nguni cattle breed preservation project. In this project, a herd of 30 Nguni heifers and 1 bull were allocated to 34 Communal Property Associations (CPA) and 40 private farming enterprises each. With its three distinct ecological zones (High, Mid and Low-veld), the Mpumalanga province poses a challenge to the Nguni preservation project since cattle have to adapt to different ecological zones in order to grow and reproduce efficiently. Knowledge of cattle herd productivity improves the understanding of the functional attributes and is useful in determining the constraints and the potential of communal beef cattle production systems. Significant differences between ecological zones were observed for age at first calving, weaning rate, calves’ birth weight and calves’ weaning weight (p < 0.05). Calving of heifers in the Mid-veld zone occurred earlier (24 months) on both ownership types compared to Highveld (28.09 months for private and 26.00 for CPA) and the Lowveld (28.35 months for both ownerships). Nguni cattle on the Highveld performed better in terms of weaning rate under both private and CPA ownerships, where the weaning rate were 93% and 80%, respectively. Calves birth weight was lower in both ownership types in the Midveld zone (22.17 kg), whereas in the CPA, the Lowveld zone had higher calves birth weights (26.80 kg). In the private ownership, the highest calves’ birth weight (25.35 kg) was on the Highveld. The calves weaning weight were significantly higher (p < 0.05) on Highveld in private ownership (190.16 kg) and lowest (160.39 kg) in the Midveld zone. For the CPA, the highest calves weaning weight was also on the Highveld (187.55) and lowest on Midveld (167.50 kg). A full range of backup services that are offered to the communities by stakeholders in the form of a beef package that includes veld and pasture management, nutrition management, beef performance, animal recording keeping, genetic evaluation and animal health management program needs thorough attention.

Drug delivery technology is currently advancing faster than at any time in biotechnology history. The challenge of drug delivery is to achieve a controlled release of therapeutic agents over an extended period. Controlled release potentially offers significant advantages over conventional dosage forms, by eliminating both under- and overdosing while maintaining a desired range of drug concentrations. An existing drug regimen for induced calving produces a declining blood profile that does not mimic the naturally occurring, gradually increasing, cortisol blood level around parturition effectively, causing animal health issues. Likewise, while the existing progesterone controlled release systems for oestrous control successfully synchronise oestrus, it is however, associated with reduced fertility and as such other drugs have to be administered to improve the fertility during oestrus. Therefore, there is a need for a drug delivery system that is capable of delivering multiple drugs at various times and patterns. This research aimed to investigate, characterize, identify steroids with high absorption rates through vaginal mucosa and evaluate the potential of an electronic drug delivery system for the delivery of steroids for either the control of the bovine oestrous cycle or induced calving. In order to identify steroids with high absorption rates across the vaginal mucosa, an in vitro permeation method was developed to screen selected steroids for their ability to permeate artificial and biological membranes. The steroids were pre-formulated to enhance their solubility and permeation through these membranes. Analytical UV and HPLC assays to characterise the pure and formulated steroidal compounds were also developed and validated. An assessment of an intravaginal Electronically Modulated Intravaginal Device (EMID) for the control of the bovine oestrous cycle or induced calving was carried out. Five different release assessment methods were investigated and critically evaluated in order to identify the most appropriate release assessment method for the EMID. These were: 1) the Drug Dissolution Test, 2) a weight loss method, 3) the dispensed weight method, 4) the determination of piston travel distance method, and 5) the rod expulsion from the EMID method. The methods investigated were critically evaluated in terms of ease of use and automation, reproducibility and cost/time savings. Optimisation of various components and construction materials of the EMID were also investigated. Animal trials were carried out using the original EMID (manufactured from polypropylene polymer) and modified inserts (manufactured from high density polyethylene polymer) to determine their retention rate in the animals. Accelerated stability testing of progesterone in suspension, oestradiol-17 tablets, cloprostenol as a powder blend and the driving mechanism of the EMID were examined. The flux of the steroids was evaluated through poly-&-caprolactone and excised cow mucosa membranes using side-by-side permeation cells. Results indicated that progesterone followed by dexamethasone acetate and dexamethasone valerate showed higher permeability values through vaginal mucosa compared to dexamethasone or its other analogues. The weight loss method of the EMID proved to be an easy and appropriate method to measure the release rate from the EMID. A high density polyethylene polymer was identified as the most ideal body material for the insert compared to polypropylene body. Also double O-ring silicone, Elastollan WYO 1388-5 and solid silicone pistons were found to be amongst the best pistons tested and all performed well compared to other piston materials. There was a low retention rate with either the original EMID or the modified inserts. Further modification of retention wings of the EMID did not improve the retention rate, but a good blood profile response was obtained from cows treated with the complete EMID containing formulated progesterone. The formulations and driving mechanism were found to be stable under the tested conditions. Therefore, the EMID has potential for commercial application of induced calving or oestrous control per vaginum administration, reliant on improvement of its retention mechanism.

Precision dairy farming technologies provide a variety of functions to dairy farmers. Little is known about dairy producer perception of these technologies. A study was performed to understand dairy producer perception of parameters monitored by precision dairy farming technologies. Calving has potential to be predicted using these same parameters and technologies. A second study was performed using two commercially marketed technologies in calving prediction. In order for these technologies to generate accurate and useful information for dairy farm use, they must accurately quantify these parameters. The final study evaluated the accuracy of five commercially marketed technologies in monitoring feeding, rumination, and lying behaviors.

The aim of this diploma thesis was to evaluate the influence of live weight in the course in rearing heifers on milk yield Fleckvieh in economically squad Určice. 420 cows of Czech Fleckvieh breed in period of 5 years (2011-2016) were evaluated. Body weight of heifers was determined by bridging the transition from individual business records to the age of 3, 6, 12 and 15 month. The influence of bodyweight heifers during rearing on the usability and functional length were evaluated, as well as the effect of the age at first calving on milk yield and functional longevity. Last but not least were determined the most common causes of retirement of cattle from the herd. No significant effects of rearing of heifers on dairy milk yield or the longevity of cows were detected.

The aim of this study was to evaluate of selected factors on milking yeild and longevity of Czech Fleckvieh cattle. There were monitored the indicators of the amount of milk for the first lactation in kg, the lifetime performance in kg, the age at the first calving, the functional longevity in days, the lenght of the service period, the lenght of the meantime days, the live weight in kg, the elimination of the causes from the breed. 273 culled cows were included. The relationship between some of the observed factors were signifiant such as the amount of milk yeild on the first lactation and the lifetime performance. In the opposite, there was no signifiant relationship between the age at the first calving and the functional longevity. The milk performance at first calving has been increasing with the age.

The aim of this thesi is the evaluation of selected impacts of elimination and longevity of Holstein and Czech spotted dairy cows on the Ing. Bohuslav Vacka´s farm in Vrchotovy Janovice according to the reason of this elimination, the age at the first calving, milk production of the first milk lactation, lifetime milk lactation and the number of milk lactation during the lifetime. I also evaluated functional longevity (from the first calving to retirement) and the longevity of life (from the birth to retirement) of retired dairy cows and the relationship between age at the first calving, milk production of the first lactation and lifetime milk production. In monitoring were included 359 pieces of cows eliminated during five years, from 1 January 2010 to 31 December 2014. From these, 217 pieces of Holstein cows and 142 pieces of Czech spotted cows. Both breeds were stalled in the same barn with the same nutrition. At the monitored group were eliminated altogether 31.22% of dairy cows. Holstein cows were excluded very often from other medical reasons (28.57%) and the Czech spotted cows for fertility disorders (45.77%). Higher milk productivity and higher average number of lactations for the life reached eliminated Holstein cows in comparison with the Czech spotted cows. Longer lifetime longevity reached Holstein cows (63 months) than Czech spotted cows (53.6 months) and among them was found highly significant difference at a significance level of p 0,001. Higher longevity and lifetime milk production in kg of milk reached Holstein cows calved in 25 to 26 months and Czech spotted cows calved within 27 to 28 months. The relationship between age at the first calving and lifetime milk production at Holstein (r = 0.018) and Czech spotted cows (r = 0.0434) proved to be an insignificant dependence and the relationship between milk production at the first lactation and lifetime milk production at Holstein (r = 0.3317) and Czech spotted cows (r = 0.4436) proved to be as a highly significant correlation (p 0.001).

The set includes 1782 heads of culling Czech fleckvieh cattle eliminated from 1 January 2012 to 1 September 2015. Influences on the first calving age, calving interval and lifetime milk yield were detected for data in the set. The following items were integrated among selected lifetime milk yield influences : genotype, herd, first calving age and first calving month. It was also tested whether the age of the first calving of milking cows is influenced by genotype and a herd. The last tested hypothesis was related to the influence of genotype and a herd on the length of the carving interval. The influence of genotype, lactation and the age of first calving cows on the way of elimination was investigated in the set as well. Multi-factor analysis of variance were used for the calculation of differences among the individual tested groups . With respect to statistical significance there was a statistically significant effect (p <0.05)of the herd and genotype on the age of the first calving cows found out. From the set it is evident that cows calved earlier reached better lifetime milk yield than cows calved at the older age (p <0.05). Another statistically significant difference (p <0.05) was found out within the first month of calving. Milking cows calved during colder periods of the year reached the higher lifetime milk yield. The influence of genotype on milk yield was not proved in this set. This also holds to reproductive parametres, there was no influence of genotype and the age of first calving on calving interval. When observing the outcome in terms of how we can positively evaluate the elimination of voluntarily culled milking cows, which is 34% .This situation is significantly lower than it is stated in literature and shows a good zootechnical care of the herds. In terms of elimination method there were the most dairy cows culled because of fertility - 31%. This fact shows that fertility is one of the main factors influencing the managament and profitability of dairy herds of cattle.