You may think skim milk tastes “watery” but water comprises approximately 87 percent of the milk right out of the teat. That’s why Curt A. Gooch, dairy environmental systems engineer with Cornell University’s PRO-DAIRY program, feels it’s so important to ensure herds receive sufficient water to stay healthy and produce at their optimal level.
Gooch spoke about “Watering Dairy Cattle” at the 2017 Winter Dairy Management meeting in Auburn, NY recently. He said that cows will drink more if it’s easy for them to access water. Several factors influence an animal’s ease of access.
Cows tend to submerge their muzzles about one to two inches in the water they drink. They should have sufficient clearance to feel comfortable while drinking. Water that’s too shallow may deter cows.
The capacity of a watering station can also minimize the amount of water cows drink. As they tire of standing for access to their water trough, cows may give up. Or, they could stand too long than optimal and waste energy, and place unnecessary stress on their hooves and legs.
“Are we adding standing time while cows are waiting at water stations like that?” Gooch said, as he showed a slide of cows crowding around a barn’s trough. “Sure we are.”
Understanding bovine behavior can help farms better accommodate their animals’ needs.
“When cows come back from milking, that’s when they like to drink,” Gooch said.
But if they don’t find clean water, easy access and sufficient depth, they may not get enough hydration.
Gooch said farms need many convenient locations for cows to drink. They should provide cows with a minimum of two feet of accessible water trough perimeter for every 15 to 20 cows.
He added that for a watering location, dairymen should install watering units in crossovers. They should provide a crossover every 80 to 100 feet and allow a minimum of 12 feet of width for a crossover with a watering unit.
As simple as it sounds, supplying enough fresh water is essential for proper hydration. Cows drink a lot — between three and five gallons per minute — and lactating cows drink about 30 to 50 gallons per day.
“Ensure that supply pipes are properly sized,” Gooch said. “The biggest mistake we make in watering systems is not making pipes big enough.”
Keeping cows hydrated helps reduce heat stress and unnecessarily expending energy.
Gooch said the upper critical temperature of a dairy cow ranges between 77 and 79 degrees, depending on her age, breed, feed intake, diet composition, previous state of temperature acclimatization, production, housing/stall conditions, tissue insulation (fat and skin), hair coat conditions, and behavior of the animal.
A cow’s normal core body temperature is 101.5 Fahrenheit. Gooch said that farmers should look for signs of heat stress, including depressed appetite, slug feeding, increased respiration, reduced conceptions, decreased stall use, decreased milk production, and increased core body temperature.
“Increased respiration will be the first thing you notice, so look for those flanks moving rapidly,” Gooch said.
The basal respiration rate of a lactating cow is about 12 to 36 breaths per minute.
Other effects can include decreased nutrient absorption, decreased feed efficiency, decreased volatile fatty acid production (even with consistent feed intakes), increased blood flow to the skin and decreased blood flow to organs.
Beyond poor watering, Gooch said several factors contribute to heat stress, including air dry bulb temperature, air relative humidity, air movement and solar radiation. Mitigating environmental stress includes shade, air velocity, air exchange and water.
Gooch said convective cooling fans operating at 400 to 600 feet per minute of air speed at the cow’s level can effectively mitigate environmental stress.
“A good place to start in getting cooling is placing fans in the milking center holding areas,” Gooch said.
Placing fans in strategic areas helps increase production.
“Put them where you want them to be, like at the resting level, at the feed bunk and at the watering area,” Gooch said, “because those are beneficial areas to be in.”
For employee safety, fans must be placed seven feet or higher or else include a screen.
Farmers have asked Gooch before if the outside rows of the barn require fans. He says, “yes, because air isn’t coming in at the same velocity. The lower fans are, the less they have to be tilted. Fans are really important to keep cows comfortable and lying down.”
Farms can also use direct evaporative cooling via cow sprinkling systems with the goal to wet the animal’s coat to the skin.
“Very aggressive rain showers will let her body heat evaporate it off,” Gooch said.
Sufficient cow cooling has proven to cut the animals’ respiration rate in about half within minutes, he added.