Related Experiment Video
Updated: Jul 23, 2025
06:52
Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure
Published on: July 19, 2018
6.4K
Air velocity spatial variability in open Compost-Bedded Pack Barn system with positive pressure ventilation
Carlos Eduardo A Oliveira1, Ilda DE Fátima F Tinôco1, Flávio A Damasceno2
1Universidade Federal de Viçosa, Departamento de Engenharia Agrícola, Av. Peter Henry Rolfs, s/n, Campus Universitário, 36570-900 Viçosa, MG, Brazil.
Anais Da Academia Brasileira De Ciencias
|July 19, 2023
Summary
Ventilation in Compost-Bedded Pack Barns (CBP) is crucial for dairy cattle comfort. This study found air velocity was often below recommended levels across most of the barn area, indicating poor ventilation efficiency.
Area of Science:
- Agricultural Engineering
- Animal Science
- Environmental Science
Background:
- Compost-Bedded Pack Barn (CBP) systems rely on adequate air velocity for dairy cattle thermal comfort and bedding quality.
- Assessing ventilation efficiency is essential for optimizing environmental conditions in CBP housing.
- Previous research highlights the link between air movement and animal welfare in confined livestock operations.
Purpose of the Study:
- To evaluate and characterize the dependence and spatial distribution of air velocity at 1.5 m height (vair,M) and bedding level (vair,B).
- To assess ventilation efficiency in an open CBP system with positive pressure ventilation.
- To identify areas within the facility with suboptimal air velocity for dairy cattle.
Main Methods:
- Conducted in a Brazilian CBP facility during winter, collecting air velocity data at 55 points across the barn.
- Measured air velocity at two heights (1.5 m and bedding level) during morning and afternoon periods over three weeks.
- Utilized geostatistics techniques to analyze spatial dependence and distribution of air velocity data.
Main Results:
- Strong spatial dependence and non-uniform distribution of air velocity were observed at both measured heights.
- Over 65% of the facility area exhibited air velocities (vair,M and vair,B) below the recommended 1.8 m∙s-1.
- Adequate ventilation was confined to the initial 20.0 m of the facility, influenced by fan line placement.
Conclusions:
- The positive pressure ventilation system in the studied CBP facility demonstrated inadequate air velocity distribution across most of the barn.
- Suboptimal air velocity levels pose a risk to dairy cattle thermal comfort and bedding management.
- Further investigation and potential adjustments to ventilation strategies are needed to improve air circulation throughout CBP systems.
Related Concept Videos
01:19Factors Affecting Pulmonary Ventilation
1.5K
Besides the pressure difference between the external environment and the lungs, the airflow rate and ease of pulmonary ventilation are also influenced by three other factors: surface tension of the fluid in the alveoli, compliance of the lungs, and airway resistance.
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
1.5K
01:26General External Flow Characteristics
234
The study of external flow is essential for creating structures and objects that interact efficiently and safely with moving fluids, such as air or water. When a body is immersed in a flowing fluid, it experiences two primary forces: drag, which opposes motion along the flow direction, and lift, which acts perpendicular to the flow. The shape, size, and orientation of the object influence these forces.Streamlined and Blunt Bodies in External FlowObjects in fluid flow are classified as...
234
01:20Assessment of Ventilation I: Respiratory Rate
1.2K
Assessment of Ventilation
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
1.2K
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
1.6K
Respiratory Depth
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
1.6K
01:27Laminar Flow
1.1K
Laminar flow represents a smooth, orderly fluid motion where particles move along parallel paths, resulting in minimal mixing between layers. Streamlined particle paths characterize this flow regime and occur under conditions where viscous forces dominate over inertial forces. The distinction between laminar, transitional, and turbulent flow is primarily determined by the Reynolds number, a dimensionless quantity calculated as:
1.1K
01:23Mechanical Ventilation II: Invasive Ventilation
179
Ventilators are essential medical equipment used to aid patients with respiratory difficulties. Their primary function is to assist or replace spontaneous breathing by providing mechanical ventilation. There are two general classes of mechanical ventilators: negative-pressure and positive-pressure ventilators.
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
179