# Microbiota in the Early Lives of Sheep: A Short Overview on the Rumen Microbiota

## TL;DR

This paper reviews how gut microbes develop in young sheep and how they affect digestion, health, and growth, with a focus on the rumen microbiota.

## Contribution

The paper provides a focused review on the early-life development of the rumen microbiota in sheep and its modulation through natural additives.

## Key findings

- The rumen microbiota in young sheep is influenced by environmental, dietary, and contact-based factors.
- Natural additives like prebiotics, probiotics, and synbiotics can improve digestion and disease resistance in lambs.
- Understanding early-life microbiota development can help improve feeding strategies and animal welfare in sheep farming.

## Abstract

Sheep have millions of beneficial microorganisms in their guts, which play key roles in digestion, growth, and overall health. From the first weeks of life, microorganisms progressively colonise the various stomach compartments, particularly the rumen, which later becomes the primary fermentation chamber in young ruminants. In this context, this review presents an overview of how gut microbiota become colonised in young lambs, as well as the environmental, dietary, and direct-contact factors that influence colonisation. Furthermore, this review also explains the use of widely recognised natural additives, including prebiotics, probiotics, and synbiotics, which may improve the digestive system and disease resistance, as well as promote lamb growth in agricultural systems. This understanding of how the gut microbiota is assembled and organised during an animal’s early life may assist farmers and scientists in developing improved feeding strategies, thereby helping to prevent digestive disorders, and enhancing animal welfare.

A key area of research is the role played by the gut microbiota in the health of sheep during the early period of life; consequently, understanding its complexity may have significant implications for sheep farming. While factors such as diet, age, health status, and environmental conditions are crucial for determining the composition of the gut microbiota, there are very few summaries on the gut microbiota in early life and only a limited number of reviews considering the gut microbiota in adult (sheep) life. Accordingly, after a brief introduction to the generic qualitative and quantitative composition of the gut microbiota in sheep, this review focuses on its development in early life, with primary attention given to the rumen. It then provides an overview of factors that may modulate the microbiota, with a particular focus on prebiotics, probiotics, and synbiotics. The optimisation of these processes in sheep may enhance digestibility, immunity, and overall production efficiency. The review also highlights key challenges associated with the adoption of management strategies based on the integration of microbial approaches in modern livestock systems with the aim of enhancing animal welfare, sustainability, and production efficiency.