Thesis--Auburn University, 2010. / Abstract. Includes bibliographic references (p.82-90).

Thesis--University of Kentucky (Ph. D.), 2003. / Title from document title page. Document formatted into pages; contains ix, 194 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 180-191).

Thesis (M.Sc.(Agric.)) -- University of Pretoria, 2008. / Abstract in English. Includes bibliographical references.

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: James G. Berardinelli. Includes bibliographical references (leaves 72-87).

Thesis (MMedVet (Gyn.))-University of Pretoria, 1998.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1995. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (MMedVet (Gyn))--University of Pretoria, 2005. / Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:35:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-15Bitstream added on 2014-06-13T19:24:35Z : No. of bitstreams: 1 castro_elc_dr_jabo.pdf: 458441 bytes, checksum: ea8d6d3919ec4a9e692914323b80803d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Três grupos de 8 touros, sendo cada grupo formado por 4 animais da raça Simental (Bos taurus taurus) e 4 da raça Nelore (Bos taurus indicus), perfazendo um total de 24 touros com idade aproximada de 30 meses foram submetidos a dietas isoenergéticas com diferentes níveis de proteína degradável no rúmen e água ad libitum. As rações foram constituídas basicamente de feno de Tifton 85, farelo de soja, milho e uréia (Nitrogênio Não Protéico) e formuladas individualmente para cada touro de acordo com a análise bromatológica dos ingredientes, peso e ingestão dos animais. Na dieta do grupo controle (C) foram seguidas as normas do NRC (1996) para nutrição de touros em reprodução. Na dieta do grupo gradual (G) foram acrescidas 30% e, após quatro semanas, 75% de proteína degradável em relação à dieta controle, através do aumento na quantidade fornecida de uréia (NNP). Na dieta do grupo Choque o nível de proteína degradável foi 110% superior à ração do grupo controle durante todo o período experimental. Os touros permaneceram em baias individuais e após o período de adaptação de 21 dias foram submetidos semanalmente a colheitas de sêmen. O sêmen dos animais foram obtidos por eletroejaculação e avaliados quanto aos exames físicos do sêmen (turbilhonamento, motilidade, vigor e concentração) e morfologia espermática durante o período experimental de 15 semanas. Foram realizadas colheitas semanais de sangue 2 horas após a alimentação dos animais com a finalidade de mensurar os níveis plasmáticos de amônia e uréia durante seu pico de produção. Os ejaculados dos touros dos grupos tratados (Cq e G) apresentaram menor turbilhonamento, motilidade, vigor e concentração em relação ao grupo controle (C) a partir da décima terceira semana de experimento (P<0,01). / Three experimental groups, each containing eight bulls, were given isoenergetic diets with different levels of ruminal-degradable protein and ad libitum water. Each group was constituted by four Fleckvieh (Bos taurus taurus) and four Nellore (Bos taurus indicus) bulls, in a total of 24 animals with mean age of 30 months. Diets were composed basically of Tifton 85 hay, soy bran, corn and urea (non-proteic nitrogen; NPN) and formulated for each animal individually, according to ingredients' bromatologic analysis, animal's weight and uptake capacity. For the Control-group (C-group) diet, NRC (1996) nutrition recommendations for bulls on reproduction were followed. In the Gradual-group (G-group) diet, 30% more ruminal-degradable protein (compared to the C-group) was added, and after four weeks, the level increased to 75% through the addition of urea (NPN). For the Choque-group (Cq-group), degradable protein level was 110% higher than in Cgroup during all experimental period. Bulls were maintained in individual boxes and after an adaptation period of 21 days, semen samples were collected. Semen was obtained through electroejaculation and analysed for physical (whirl movement, motility, vigour and concentration) and morphological characteristics during the period of 15 weeks. Blood sampling was performed weekly two hours after feeding in order to measure ammonia and ureal levels during its peak production. Treatment groups (Cq-group and G-group) presented lower whirl movement, motility, vigor and concentration than the C-group after the 13th week (P<0,01). Spermatic morphology showed increased levels of greater spermatic defects for taurines (P<0,05) during all experimental period, but no significant differences were observed among treatments for these characteristics. Significant differences in plasmatic urea (P<0,01) occurred.

Thesis (MSc. (Animal breeding and genetics )) --University of Limpopo, 2006 / The objective of this study was to estimate genetic parameters for weekly body weight of feed intake of individually fed beef bulls at centralized testing stations in South Africa using random regression models (RRM). The model for cumulative feed intake included the fixed linear regression on third order orthogonal Legendre polynomials of the actual days on test (7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77 and 84 day) for starting age group and contemporary group effects. Random regressions on third order orthogonal Legendre polynomials were included for the additive genetic effect of the animal and the additional random effect of weaning-herd-year (WHY) and on fourth order for the additional random permanent environmental effect of the animal. The model for body weights included the fixed linear regression on fourth order orthogonal Legendre polynomials of the actual days on test for starting age group and contemporary group effects. Random regressions on fourth order orthogonal Legendre polynomials were included for additive genetic effects and additional uncorrelated random effects of the WHY and the permanent environment. The residual effects for both traits were assumed to be independently distributed with heterogeneous variance for each measurement period. Variance ratios for additive genetic, permanent environment and WHY for cumulative feed intake at different days on test ranged from 0.07 to 0.10, 0.53 to 0.77 and 0.14 to 0.37, respectively. Variance ratios for additive genetic, permanent environment and WHY for weekly body weights at different test days ranged from 0.26 to 0.29, 0.37 to 0.43 and 0.26 to 0.34, respectively. Estimates of genetic correlation among the same trait (body weight or feed intake) measured at different test days were generally high (>0.80) for any give test pair. The WHY had a significant contribution in variation of performance of bulls on test, despite the 28-day adjustment period. RRM provided the opportunity to study changes in genetic variability within the studied traits over time. Random Regression Models could be used in the National Genetic Evaluation of beef bulls at central performance testing stations in South Africa.

Dairy cattle breeding is still taking the first place of it‘s production. Growing requirements in the national and international markets require animals productivity, increase of genetic potential and development of production quality. The growth of animal’s genetic potential promote the use of bull’s sires with high value of breed. There are a lot of the bulls sires witch are improving the breed. So they constitute line of descent or related groups. The company „Litgenas“ during 14 work years has been used 11 line of descent and related groups. There are 4 the main line of descent and related groups: 1. W. A. BURKE LAD 697789 line ( 920 ); 2. R. O. R. A. ELEVATION 1491007 US1491007 related group ( 931 ); 3. O. IVANHOE 1189870 line ( 960 ); 4. P. F. ARLINDA CHIEF TL 1427381 related group ( 982 ). Comparing to the controlled cows’ bands of 2004-2005 years the supply of company coincides with the demand of market. I was using „R“ statistic analysis packet, counting arithmetic avarages of values of bulls breeds and coefficient of variation. Also during the communication with farmers I noticed that the requirements of bulls genealogy schemes which are used by the company „Litgenas“ became much bigger. So due to the information of bulls line of descent which were cumulated by the computation centre “VIC” of Lithuania I made bulls sires genealogy schemes. All farmers, selectioners of company, regions breeding inspectors and inseminators are using this poster. The... [to full text]