Effects of calcium salts of palm fatty acids on nutrient digestibility, energy partitioning and production responses of lactating dairy cows

• Autor(a) principal: Santos Neto, José Maurício dos
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/11/11139/tde-11032020-162956/
• topic: Gordura inerte; Grazing cows; Inert fat; Meta-análise; Meta-analysis; Pasto tropical; Tropical pastures; Vacas em pastejo

The objective of this thesis was to evaluate the effects of calcium salts of palm fatty acids (CSPF) on nutrient digestibility, energy partitioning and production responses of lactating dairy cows. A meta-analysis was performed to evaluate the effects of CSPF compared to non-fat supplemented control diets on nutrient digestibility and production responses of lactating dairy cows receiving TMR. In addition, we also used a meta-analysis to evaluate whether experimental designs classified as either continuous (completely randomized and randomized as block) or change-over (crossover and Latin square) impact the responses of supplemental CSPF (Chapter 2). More two studies were performed to evaluate the effects of CSPF on nutrient digestibility, energy partitioning, and production responses of lactating dairy cows grazing on tropical pastures. One experiment evaluated CSPF in mid-lactation dairy cows (Chapter 3), and the other evaluated the dose response effects of CSPF in early-lactation dairy cows, with a potentially positive carryover effect (Chapter 4). The meta-analysis indicated that CSPF increased NDF digestibility and improved the production responses of lactating dairy cows receiving TMR. In addition, we did not observe interactions between experimental designs and CSPF supplementation (Chapter 2). Feeding CSPF to mid-lactation dairy cows grazing on tropical pasture decreased OM intake, but did not affect energy intake, increased OM, NDF and fatty acid (FA) digestibility, and altered energy partitioning, promoting increases in the yields of milk, milk fat, 3.5% FCM, and ECM (Chapter 3). Increasing CSPF to early-lactation dairy cows grazing on tropical pastures linearly decreased DMI, but did not affect energy intake, linearly increased NDF and quadratically increased FA digestibility, and linearly increased energy output for milk, promoting linear increases in the yields of milk, milk fat, 3.5% FCM, and ECM. Feeding CSPF to early-lactation dairy cows grazing on tropical pastures had a positive carryover effect on milk production (Chapter 4). Our results indicate no reason for the restrictive use of change-over designs in CSPF supplementation studies and meta-analyses. Feeding CSPF to lactating dairy cows reduced DMI, but did not affect energy intake, increased NDF and FA digestibility, and altered energy partitioning, promoting increases in the yields of milk, milk fat, and 3.5% FCM. Also, feeding CSPF to early-lactation dairy cows grazing on tropical pastures had a positive carryover effect on milk production.