Fast Fact: How much water does a calf excrete? – Dr. Noah Litherland, Vita Plus

Posted on December 21, 2016 in
By Dr. Noah Litherland, Vita Plus dairy youngstock technical specialist

Question:  How much water does a calf excrete?

Quick answer:  Calves between 35 and 42 days of age excrete between 4.6 and 9.8 pounds of urine per day, depending on the plane of nutrition fed.

A bit more…

By Dr. Noah Litherland, Vita Plus dairy youngstock technical specialist

Question:  How much water does a calf excrete?

Quick answer:  Calves between 35 and 42 days of age excrete between 4.6 and 9.8 pounds of urine per day, depending on the plane of nutrition fed.

A bit more:  The primary sources of water intake for nursery calves are water from milk or milk replacer and, to a lesser extent, drinking water.  Understanding calf water intake and excretion can help us predict bedding needs and develop improved moisture management plans.

A Journal of Dairy Science article in press from Dr. Pete Erickson’s lab group at the University of New Hampshire reported water intake and urinary water output by dairy calves fed three planes of milk replacer nutrition (Table 1).  Drinking water intake was low, possible due to how the water was offered.  The authors state drinking water was available at all times, but do not report timing or temperature of drinking water.  Typically, we see greatest water intakes when offering modest amounts of warm water within 10 minutes after completion of the milk meal.

As expected, water intake from milk replacer represented the majority of water intake until weaning when drinking water intake abruptly increased.  Urine output was measured through collection via catheters placed in a subset of calves in this experiment.  Urine output ranged from approximately 60 to 80 percent of total water intake with greater urine output measured in calves fed an accelerated plane of nutrition. (The authors noted significantly greater urine nitrogen outputs with increased plane of nutrition.)  Fecal moisture also contributes to water in the calf environment, but was not reported in this study.  Calves with loose stool contribute greater amounts of water to their environment than calves with firmer and drier stool.

A 1918 publication by J. W. Whisenand at the Illinois experiment station demonstrated the water-absorbing capacity of a variety of livestock bedding materials.  Wheat straw can absorb about twice (2.2) its weight in water.  If we do a simple calculation with the data above, calves on the control diet would require about 2.1 pounds of wheat straw per day to soak up their urine, which adds up to about 125 pounds of wheat straw in two months.  In contrast, the accelerated-fed calves would require 4.4 pounds of wheat straw per day to soak up their urine (about 267 pounds of wheat straw in two months).  These calculations do not take into account evaporation or drainage.

In summary, the feeding program has an impact on water intake and urine output.  Milk replacer programs that meet, but do not greatly exceed nutrient requirements, and balance protein and energy intake increase calf efficiency.  Providing adequate and timely bedding with adequate drainage (drains in concrete floors or sand under hutches) will help keep calves dry during the nursery phase.  Additionally, efforts to increase starter grain intake will firm up fecal output and increase water retention by the calf.  Finally, ventilation systems that remove moisture from the barn without chilling calves should continue to be investigated.

Category: Calf and heifer nutrition
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