METHANE MITIGATION, FEED EFFICIENCY, AND HEAT STRESSIN REPLACEMENT HEIFERS: NUTRITIONAL ANDMANAGEMENT APPROACHES FOR SUSTAINABLE DAIRYPRODUCTION
type: CreativeWork
description: The 21st century is characterized by profound social and environmental changes. Global population is expected to reach 10 billion people by 2050, generating a great demand for food production. At the same time, climate change has already increased the average global surface temperature by approximately 1.5 °C compared to the pre-industrial era, posing significant threats to human, animals, and environmental health. Agriculture and livestock farming play a central role in this scenario, as they are essential for food supply but are also required to drastically reduce their greenhouse gas emissions. In addition, global warming exerts a direct negative impact on animal health and welfare, leading to important economic losses in recent years. The increase in average temperatures has also been associated with a higher frequency of extreme weather events, such as droughts and heatwaves, which further challenge farm management and livestock productivity. The overall aim of this PhD thesis was to investigate nutritional and management strategies to better address the challenges faced by livestock production in the 21st century. In particular, the research focused on improving feed efficiency, mitigating methane emissions, and alleviating the detrimental effects of heat stress in Italian Holstein dairy heifers. The first study (Chapter 3) describes an in vivo trial evaluating the inclusion of increasing doses of lysozyme in the diet of dairy heifers to assess the effects of this antimicrobial enzyme on enteric methane production. The results showed a 12% reduction in methane emissions in the group receiving the highest lysozyme dose (10.000 FPI U/Kg DM of lysozyme), without significant effects on animal performance or welfare. The exact mechanisms by which lysozyme acts in the rumen to decrease methane production are still not fully understood; therefore, further analysis on ruminal fermentation patterns and microbial populations need to be carried out to clarify this aspect…
abstract: The 21st century is characterized by profound social and environmental changes. Global population is expected to reach 10 billion people by 2050, generating a great demand for food production. At the same time, climate change has already increased the average global surface temperature by approximately 1.5 °C compared to the pre-industrial era, posing significant threats to human, animals, and environmental health. Agriculture and livestock farming play a central role in this scenario, as they are essential for food supply but are also required to drastically reduce their greenhouse gas emissions. In addition, global warming exerts a direct negative impact on animal health and welfare, leading to important economic losses in recent years. The increase in average temperatures has also been associated with a higher frequency of extreme weather events, such as droughts and heatwaves, which further challenge farm management and livestock productivity. The overall aim of this PhD thesis was to investigate nutritional and management strategies to better address the challenges faced by livestock production in the 21st century. In particular, the research focused on improving feed efficiency, mitigating methane emissions, and alleviating the detrimental effects of heat stress in Italian Holstein dairy heifers. The first study (Chapter 3) describes an in vivo trial evaluating the inclusion of increasing doses of lysozyme in the diet of dairy heifers to assess the effects of this antimicrobial enzyme on enteric methane production. The results showed a 12% reduction in methane emissions in the group receiving the highest lysozyme dose (10.000 FPI U/Kg DM of lysozyme), without significant effects on animal performance or welfare. The exact mechanisms by which lysozyme acts in the rumen to decrease methane production are still not fully understood; therefore, further analysis on ruminal fermentation patterns and microbial populations need to be carried out to clarify this aspect…
author: MELI, GIOVANNA
language: eng
keywords: Replacement heifer, enteric methane, feed efficiency, heat stress mitigation, Settore AGRI-09/B - Nutrizione e alimentazione animale
date published: 2026-05-08
date modified: 2026-07-27T20:18:58Z
provider: Università degli Studi di Milano
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Università degli Studi di Milano

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2434/1241656