Designing the holding pen with airflow and evaporative cooling in mind might help keep the cows comfortable.
A cow's internal temperature can rise rapidly in the holding pen without any cooling system. These heat abatement difficulties necessitate a more robust cooling technique for the parlor and holding pen.
Each cow is allotted around 15 square feet of space in the holding pen. The BTU per hour per square foot (BTU/hr/sq. ft.) in the holding pen of the occupied area is 6.50 times higher than the barn she was just in. Because the cows in the holding pen are so close, more heat transfer can occur between them.
Since both cows' skin temperatures are almost identical, direct skin-to-skin contact does not transfer net heat. Driving airflow down around cows, in addition to soaking (and, if necessary, high-pressure fogging), is the only way to achieve convective heat loss.
The cow's respiratory system also contributes heat and moisture to the conclusion. With larger pen sizes comes a greater chance of raising internal body temperature exceeding 102.2oF (39°C).
Save the Calves by Cooling the Cows
Milk output decreases as a direct result of heat stress. However, thermal stress in the holding pen may deprive your dairy through premature embryonic mortality. Even if it is for a short period.
Embryos are especially vulnerable to high internal temperatures in the first five days after conception. This is because they lack a protective protein. Embryonic loss is 3.7% higher in the summer than in the winter.
Moreover, the studies show that a 7% drop in fertility occurs for every 1°F increase in core body temperature. It has been anecdotally observed that dairies implementing more effective parlor and holding pen cooling enjoy growth in reproductive performance.
A Peep Inside the Parlor
When temperatures rise to dangerous levels, it's best to adjust ventilation in your parlor to coincide with the direction of the wind. The purest air should be where food is harvested. You can bring air from the parlor into the holding pen.
Heat, humidity, hair, dirt, and dander are the principal elements that air carries to the harvesting area. This is common if the airflow is directed from the holding pen into the parlor.
Regardless of the parlor design, it is essential to incorporate recirculation fans. Make sure they are sized appropriately for the space to force air onto the cows during high heat stress. This method can also be used to make workers more at ease.
Some dairies equip the decks of their parallel parlors with soaker systems. On the other hand, the rotary parlors' spray wands are placed twice. Once after the unit attachment zone and once near the exit.
If you use these, the water level will go from the shoulder to the loin. But it won't drain from the udder.
Mastitis is more likely to develop if water gets on the udder. The proper distance for a sprinkler's nozzle to spray is 20 feet from the parlor's door. The strong airflow prevents water from dripping onto the udder as the cow enters the parlor.
Setting Up the Holding Pen
The air sucked into the parlor is added to the holding pen's air exchange rate. Traditional strategies that have been proven to be less effective include:
Curtain ventilation systems circulate air over the width of your greenhouse. Because greenhouses are narrow and long, the new air is better distributed than end wall inlets, as is common in mechanical systems.
- Using curtain sidewalls
- Using recirculation fans above cows in the holding pen
Compared to the typical arrangement in a dairy barn, the recirculation fans in a holding pen must be placed much closer to each other laterally and longitudinally.
Fans should be at most three fan diameters apart. It is the best distance to get air speeds over the cows of 5+ mph (200 meters per second).
Minimum airflow rates of 1,000 cubic feet per minute per cow (cfm/cow) is a general recommendation, with rates of 1,500 cfm/cow or more ideal. This is not a recirculation fan but rather a fresh air exchange system.
These recirculation fans should be aimed downward at the cows along with the soaker and high-pressure fogging method.
A recent trend has been toward including fresh-air injection fans in holding pen layouts. You can use these injection fans with high-pressure fogging. Doing so reduces the air temperature as a secondary soaking system under the right conditions. To achieve ventilation and dehumidification of the holding pen, you can consider either active exhaust, passive exit, or hybrid. You can also use curtains or permanent polycarbonate panels to close off the side walls, making for a more confined space.
Holding Pen Ventilation: Cross-Vent or Tunnel-Vent?
According to research, cooling a wet cow with air blown in a tunnel down the length of a holding pen takes roughly half as much time. Also, it takes about 50% more airspeed as if the air were blown directly into the cow's side.
Thanks to the cross-vent design, the cows in the holding pen face opposite the airflow. This may work better than the tunnel method standard in the holding pen.
As we know, the air will be diverted up and over the cows by the crowd gate support wall (or, in the case of open gating, by the outer row of cows). So, this strategy is only effective if you redirect the recirculation fans.
Both ways of designing need a recirculation fan. Also, it's vital to have an automated control system to deal with fans, soaking, and high-pressure fogging, if required.
Execute it Today
The results of Tables 1 and 2 show the monitoring breathing rate (BPM) and the temperature of the back of the udder, respectively. These two are essential to determine how well the cooling system works.
A heart rate of over 60 beats per minute or an udder temperature of around 94 degrees Fahrenheit (34.5 degrees Celsius) indicates an elevated internal body temperature. The best way to test your barn cooling system is to observe the higher-yielding cows entering the parlor.
Do you have an efficient system for cooling the areas where cows spend most of their time?
Check the middle third of the cow's group to check if they have warmer or colder core temperatures than the first group. Finally, keep an eye on the final group for the same pattern.
A good parlor and holding pen design will keep the cows cool in one of the farm's most important places. Many important factors play an essential part here.
When planning the ventilation system for your dairy, it is highly recommended that you speak with professionals. Choose those who have relevant experience in ventilation systems.
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