Optimizing dairy cow performance during transition period and early lactation: a study of the use of ultra-diluted complexes in diets and close-up feeding accuracy

• Ano de defesa: 2024
• Autor(a) principal: Gheller, Larissa Schneider
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Acurácia de dietas; Compostos ultradiluídos; Dairy cows; Diet accuracy; Período de transição; Transition period; Ultra-diluted compounds; Vacas leiteiras
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/74/74131/tde-02082024-090816/

The transition period from three weeks before to three weeks after calving in dairy cows is characterized by significant metabolic changes that can be monitored to prevent adverse events in cow health. Strategies to minimize adverse effects and ensure success in future lactations, including the use of ultra-diluted complexes and the evaluation of nutritional accuracy and its effects, require further investigation. In this context, this thesis has been divided into two chapters. In the first chapter, the administration of ultra-diluted (UD) complexes to cows during the transition period and early lactation was evaluated. Thirty multiparous pregnant cows were blocked and randomly assigned to either a placebo control group or a UD group. The results showed that although the use of UD did not affect the cows\' milk production, those fed UD tended to have lower somatic cell counts. In addition, a trend toward improved liver health was observed in cows in the UD group. These results suggest that the use of UD may provide benefits to dairy cows when used during the transition period and early lactation. The second chapter focused on the evaluation of dry cow diets during the close-up period, investigating the accuracy and precision of nutrient composition and its effect on cow performance at the beginning of lactation. Close-up diet samples were collected every four weeks during six visits to 40 dairy farms. The diets formulated by the nutritionists on each farm were also collected. The diets offered did not exactly match the formulated diets, with considerable variability in nutrient levels. Our results showed that greater variability in non-fiber carbohydrates (NFC) negatively affected liver health in fresh cows. Variability in fat and NFC affected serum β-hydroxybutyrate concentrations, and variability in NFC affected blood glucose levels. Non-esterified fatty acid concentrations were influenced by variability in dry matter and crude protein content of the diets. The results highlight the importance of maintaining consistency between diet formulations and feeding practices to optimize dairy herd performance and health. Therefore, integrating these approaches can help improve cow health and performance while promoting sustainable dairy production practices.