The fundamentals of barn ventilation for dairy goats

When it comes to dairy goat health and performance, the right environment creates a foundation for them to thrive. Good barn ventilation provides clean air to exhaust common pollutants from the barn, reduces animal stress and decreases the risk of illness. Evaluate ventilation systems in your barn to ensure you are providing an optimal environment.

Clean air as a ‘nutrient’

Clean air provides benefits to the health and overall performance of dairy goats. Lungs and intestines are key epithelial tissues. Inflammation in the respiratory tract can increase the risk of systematic inflammation. Respiratory disease in part is a result of environmental stress. While it compromises the immune system, pathogen and parasite loads can increase in the respiratory tract.

Furthermore, stress due to low air quality or cold and heat stress can increase blood cortisol, a stress hormone, stimulating an immune response. Immune system stimulation is energetically expensive. The immune system uses glucose as fuel. When the immune system uses more glucose, does produce less milk.

Defining air quality

Maximizing air quality and reducing common pollutants is a key goal of the ventilation program. Pollutants can originate from herd animals, the bedding pack, ensiled feeds, and manure storage. Ammonia strips can be used to evaluate air quality. If air quality in the barn is adequate, the strip will read less than 10 parts per million (ppm). If the strip reads more than 10 ppm, consider where you can make adjustments in your barn to reduce common pollutants.

Thermal stress

Without proper ventilation, the risk of cold stress and heat stress in dairy goats increases substantially.

To avoid cold stress, the goal should be to exchange air without causing drafts. Bacteria activity is less active in the bedding pack in cold temperatures, and the focus should be on moving moisture out of the barn.

Signs of heat stress include an increased respiration rate, open-mouth breathing, increased body temperature and increased standing time.

Components of dairy goat cooling include:

• Shade
• Air velocity: Fans, tunnel ventilation
• Water: Misters, evaporative cooling
• Time: Amount of time it takes animals to cool down when they are stressed

Key ventilation considerations

It is important to consider the air speed and air exchanges occurring when evaluating ventilation in your barn. The minimum target air speed in a barn is 60 feet per minute. This is considered “still air” with no draft that will not disturb the bedding.

Air exchanges are the number of times the air volume turns over (exchanges) per hour. In the winter, it is important to provide fresh air. A minimum of four air exchanges per hour for young kids and a target of six to eight air exchanges for adult does is standard. In the summer, it is important to provide cool, fresh air. The target should be 20 to 60 air exchanges per hour.

Different methods to evaluate air exchanges in each pen:

• Smoke: Visual approach to measuring air changes. This allows you to visualize where the air is moving in the barn. You can also find dead and/or drafting spots.
• Hot wire anemometer: Measures low speed air movement. This is a very sensitive tool and takes precise measurements.

The preferred barn orientation for proper ventilation is east and west. To avoid wind shadows, keep barns at least 50 feet apart and pay attention to prevailing winds.

Various types of ventilation systems producers can incorporate:

• Natural ventilation: Open or curtain sidewalls
• Positive pressure tubes and exhaust fans: Wall or chimney
• Pusher fans: Placement is key; set them where goats are resting
• Power ventilation: Tunnel or cross ventilation

Most importantly, monitor animal performance and behavior throughout the year. Animal indicators of poor ventilation include bunching against barriers, crowding close by or away from fans, abnormal lying behavior, and goats choosing to sit in wet bedding.

Consistently evaluating your barn ventilation will benefit your herd and overall success. It is important to ask yourself what ventilation systems you prefer and make changes when needed. Reach out to your Vita Plus consultant to discuss ventilation options for your barn.

Noah Litherland, Ph.D., presented on this topic at the 2024 American Dairy Goat Association National Conference in Lake Geneva, Wisconsin.