https://repositorio.ifgoiano.edu.br/handle/prefix/263 2026-04-16T03:09:05Z 2026-04-16T03:09:05Z Leonardo, Alice Alves Batista https://repositorio.ifgoiano.edu.br/handle/prefix/6521 2026-04-15T14:34:54Z 2025-12-17T00:00:00Z

Título: Modelos não lineares para curva de crescimento de fêmeas bovinas jovens Autor(es): Leonardo, Alice Alves Batista Primeiro Orientador: Ribeiro, Jeferson Corrêa Primeiro Membro da Banca: Oliveira, Eliandra Maria Bianchini Segundo Membro da Banca: Santos, Wallacy Barbacena Rosa Abstract: Brazil ranks third worldwide in milk production, with 35.4 billion liters produced in 2023, highlighting the expansion of the national dairy sector. To support this growth, herd management practices based on zootechnical indicators—especially during the rearing phase— are essential. Growth curves are valuable tools to describe animals’ body development over time and to estimate biological parameters such as mature weight, growth rate and age at first calving. This study evaluated growth patterns of ½ Holstein × ½ Gir heifers raised at IF Goiano – Campus Morrinhos, monitored monthly from birth to 690 days of age. Seven heifers were included and monthly body weights were fitted to several nonlinear models (Gompertz, von Bertalanffy, Meloun I, Meloun II and Weibull). Model performance was assessed using percentage of convergence, coefficient of determination (R²), mean prediction error (MPE), Akaike information criterion (AIC) and Bayesian information criterion (BIC). Results indicated poor performance for Meloun I and Weibull models (low convergence and high prediction errors). The Gompertz model provided the best fit (R² = 0.99; MPE = 29.8; AIC = 196.7; BIC = 196.5) with 100% convergence, while von Bertalanffy showed full convergence but inferior fit by other criteria. We conclude that the Gompertz model is the most suitable to describe growth of ½ Holstein × ½ Gir heifers under the studied conditions, offering reliable estimates to support rearing management, genetic selection and productivity improvements in dairy herds. Editor: Instituto Federal Goiano Tipo: Trabalho de Conclusão de Curso

2025-12-17T00:00:00Z Santos, Nathilla Mirelly Felipe dos https://repositorio.ifgoiano.edu.br/handle/prefix/6519 2026-04-15T13:48:53Z 2026-03-23T00:00:00Z

Título: GENETIC IMPROVEMENT FOR MILK PRODUCTION Autor(es): Santos, Nathilla Mirelly Felipe dos Primeiro Orientador: Ribeiro, Jeferson Corrêa Primeiro Membro da Banca: Santos, Wallacy Barbacena Rosa dos Segundo Membro da Banca: Oliveira, Eliandra Maria Bianchini Abstract: Genetic improvement of dairy zebu cattle plays a fundamental role in the development of dairy farming in tropical regions, contributing to the formation of more productive, fertile, long lived herds adapted to environmental conditions. In this context, the present work aimed to analyze, through a literature review, the main tools and strategies applied to the genetic improvement of these herds, with emphasis on phenotypic and genomic selection, evaluation of functional characteristics, lactation curve, heritability, and planned crosses. The methodology adopted was based on the consultation and analysis of scientific articles, books, technical documents, and specialized publications on the subject, prioritizing studies related to milk production in zebu cattle. The results showed that the integration of productive, morphological, and genetic information increases the accuracy in identifying superior animals, favoring consistent gains in production, reproductive efficiency, health, hardiness, and adaptation to the tropical environment. Furthermore, it was found that strategic crossbreeding between zebu and taurine cattle, especially with Girolando, enhances heterosis and genetic complementarity effects, promoting more efficient and sustainable systems. It is concluded that the integrated use of these strategies is an indispensable tool for strengthening tropical dairy farming, making production systems more competitive and economically viable. Editor: Instituto Federal Goiano Tipo: Trabalho de Conclusão de Curso

2026-03-23T00:00:00Z Silva, Priscylla de Fátima da Costa https://repositorio.ifgoiano.edu.br/handle/prefix/6514 2026-04-14T22:48:50Z 2025-10-09T00:00:00Z

Título: MODELOS NÃO LINEARES EM DADOS DE CRESCIMENTO DE BOVINOS DE CORTE Autor(es): Silva, Priscylla de Fátima da Costa Primeiro Orientador: Ribeiro, Jeferson Correia Primeiro Membro da Banca: Cesário, Andreia Santos Segundo Membro da Banca: Santos, Wallacy Barbacena Rosa dos Abstract: This study aimed to compare the performance of five nonlinear models—Gompertz, Meloun I, Meloun II, von Bertalanffy, and Weibull—in describing the growth of beef cattle under a confinement system. Data from 6,365 animals were analyzed, with weights collected at different productive stages, adjusted using nonlinear regression, and evaluated according to the following criteria: convergence percentage, coefficient of determination (R² and adjusted R²), mean prediction error (MPE), Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC).The results indicated a trend of reduced weight variability throughout the productive cycle, especially during confinement, promoting uniformity within the herd. Among the models tested, the Gompertz model showed balanced performance (R² = 0.9208; convergence = 85.55%; MPE = 0.5619; AIC = 58.3891; BIC = 78.1959). The von Bertalanffy model achieved a higher R² (0.9421) and lower MPE (0.3563) but lower convergence (78.90%). The Weibull model stood out for the lowest AIC (55.8660) and BIC (76.1417) values, although limited by its low R² (0.6021). The Meloun I and II models showed unsatisfactory performance, with low explanatory power and high prediction errors.These results reinforce the applicability and relevance of the Gompertz model as a tool for nutritional, reproductive, economic, and genetic improvement planning in beef cattle production. Editor: Instituto Federal Goiano Tipo: Trabalho de Conclusão de Curso

2025-10-09T00:00:00Z Silva, Guilherme de Moura https://repositorio.ifgoiano.edu.br/handle/prefix/6505 2026-04-13T19:53:07Z 2024-12-11T00:00:00Z

Título: FATORES AMBIENTAIS E FISIOLÓGICOS NA TAXA DE CONCEPÇÃO DE RECEPTORAS BOVINAS DE LEITE Autor(es): Silva, Guilherme de Moura Primeiro Orientador: Camargos, Aline Sousa Abstract: The conception rate after embryo transfer in dairy cattle recipients is a determining factor for reproductive success on dairy farms. However, adverse weather conditions during the procedure are often cited as an obstacle to the effectiveness of this technique. The objective of this study was to verify whether the temperature and humidity index (THI), wind and temperature of the dairy recipient, at the time of embryo deposit in the uterine environment, influence the conception rate at 30 and 55 days of gestation, throughout the year. This study was developed based on a data survey carried out at the Samvet Embriões Laboratory, in the rural area of Morrinhos, Goiás, with dairy cattle recipients of the crossbred Holstein-Zebu breed, between March 2023 and March 2024. The data analyzed included transrectal temperature of the recipients at the time of embryo deposition. Thirty-eight recipients were evaluated, with an average age of 8.8 years and body condition score between 3.0 and 4.0, managed in an extensive system and fed with pasture, corn silage with BRS Capiaçu, concentrate and mineral salt, depending on the time of year. Pregnancy diagnosis was performed by ultrasonography at 30 days and confirmation at 55 days. Environmental conditions, such as temperature and humidity index (THI), wind speed and ambient temperature, were monitored by the Meteorological Station of the Goiano Federal Institute. Statistical analysis, by logistic regression, evaluating the influence of factors: age of the recipients, season of the year, rectal temperature, THI and wind on the conception rates at 30 and 55 days of gestation. The age of the recipients did not significantly influence conception, which were 46.42% and 32.14% in animals aged 1 to 3 years; 23.07% and 19.23% in animals aged 4 to 7 years; 29.41% and 23.52% for animals aged over 20 years at 30 and 55 days of gestation, respectively. The conception rates were 16.66% and 0.00% when the rectal temperature was below 38.0 ºC, 32.14% and 26.19% between 38.0 ºC and 39.3 ºC, and 28.57% and 14.28% above 39.3 ºC at 30 and 55 days of gestation, respectively. When the THI was below 74, the rates were 31.81% and 24.24%; between 74 and 79, 29.03% and 16.12% at 30 and 55 days of gestation, respectively. When the wind speed was below 5 km/h, the conception rates were 22.00% and 16.00%; speed between 5 and 8 km/h, 44.82% and 31.03%; and above 8 km/h, 33.33% and 33.33% at 30 and 55 days of gestation, respectively. Specifically, the age of the recipients, the THI, the season of the year, the rectal temperature and the wind did not have a significant impact on the gestational success rates in the climatic conditions described, contradicting other studies that indicate a greater influence of these parameters on the conception rates. This divergence in relation to the literature may be associated with variables not considered in this study or with particularities of the management and specific conditions of the herd analyzed. Based on the results, it can be concluded that there was no significant interference of environmental and physiological factors in the conception rate of dairy cow recipients throughout the period evaluated, in the conditions of this study. Editor: Instituto Federal Goiano Tipo: Trabalho de Conclusão de Curso

2024-12-11T00:00:00Z