Dairy cows and milking facilities require a reliable high quality water supply. Dairy production is changing with larger production units being planned and constructed. These dairy facilities require a water supply that can deliver high quality water to the cows at all times in sufficient amounts to meet both physiological and sanitation needs of the facility.

The data reported in the literature for water consumption for dairy facilities varies considerably. For example, in three different studies the water needs for lactating cow consumption, and milking center cleaning range between 40 to 50 gallons fresh water per cow per day. In these studies the free stall units were flushed with recycled lagoon water in all areas except the milk parlor and milk room. This concept reduces the amount of water that is introduced into the waste management system.

Texas data illustrates that water use on eleven dairy farms varied widely, depending on the type of manure removal system and other factors. The greatest variable was the use of sprinkler cow wash systems and/or flush systems versus manual manure removal. The total amount of fresh water used for sanitation and manure removal averaged 39.6 gallons per cow per day. The mean value for each farm ranged from 12.3 to 69.2 gallons per cow per day. The water used for cattle drinking water troughs on seven of the dairies studied averaged 28.7±12.0 gallons per cow per day. Thus the Texas data average fresh water use per cow per day for sanitation and drinking was 68.3 gallons. Their data showed wide differences in water use for facilities that flushed or had cow sprinklers versus those that used manual cleanup. The average water use for milking parlors and holding pens without flush or cow sprinklers averaged 19.9±14.0 gallons per cow per day. In contrast, milking parlors and holding pens with sprinkler cow washers used an average of 47.1±17.7 gallons per cow per day.

Calculating Herd Requirements for Fresh Water

It is possible to estimate fresh water use on individual dairies, even with the wide variation reported in the literature. Estimates for total requirements can be developed for drinking water, wash pen sprinklers (if used), and milk house and parlor. Water needs can be estimated by completing Worksheet 1 (requires Adobe Acrobat) with information found in Tables 1-4.

Drinking Water Needs

Drinking water needs can be determined by using the information found in Table 1 and Table 2. Table 1 shows a typical herd makeup assuming a uniform year around calving, 13 month calving interval, a 33% replacement rate (1/2 supplying a calf), 50% female calves and males sold at birth for a 100 lactating cow herd.


Table 1: Typical Dairy Herd Composition
Category Number % of herd Avg. weight (lbs.)
Milking cows 83 83 1400
Dry cows 17 17 1550
Total mature cows 100    
Heifers      
16 - 24 months 42 38 1050
13 - 15 months 13 12 800
9 - 12 months 19 17 600
5 - 8 months 19 17 400
3 - 4 months 9 8 250
0 - 2 months 9 8 150
Total replacements 111    

Water intakes for dairy cattle are influenced by several factors including dry matter intake, milk production, ambient temperature, and sodium intake. However, Table 2 provides a good estimate of water intake based upon size, milk production and temperature. The data from the water intake table when matched with the herd makeup table will estimate herd drinking water.


Table 2: Dairy Cattle Water Intake
Weight (lb) Milk (lb)  40° & below  60°   80°F 

Lactating cows

1400 202 12.0 14.5 17.9 gal/day
  602 22.0 26.1 24.7
  802 27.0 31.9 38.7
  1002 32.0 37.7 45.7

Dry cows

14001 9.7 12.0 16.2
16001   10.4 12.8 17.3

Heifers

12001   8.7 10.8 14.5
800   6.3 7.9 10.6
400   3.7 4.6 6.1
200   2.0 2.5 3.3
1 Maintenance and pregnancy
2 Maintenance and milk production

Wash Pen Needs

The wash pen can be a large user of fresh water on typical dairies. The amount used is dependent on line pressure, sprinkler orifice, number of sprinklers and minutes per day used. Table 3 shows the gallons per minute per sprinkler with different line pressure in pounds per square inch. The number of sprinklers in the wash pen, the minutes used per day and the nozzle discharge will determine water used in the wash pen.


Table 3: Nozzle Discharge (gpm)
  1/8" dia. 9/64" dia. 5/32" dia. 11/64" dia. 3/16" dia.
40 psi 2.96 3.74 4.61 5.54 6.64
45 psi 3.13 3.99 4.91 5.91 7.03
50 psi 3.3 4.18 5.15 6.19 7.41
55 psi 3.46 4.37 5.39 6.48 7.77

Milk House and Parlor Needs

Milk house and parlor waste can be estimated from data found in Table 4.


Table 4: Volume of Milkhouse and Parlor Wastes
Washing Operation Water Volume
Bulk Tank  
Automatic Wash 50 to 60 gal. per wash
Manual Wash 30 to 40 gal. per wash
Pipeline, in parlor
Volume is higher for long stanchion barns)
75 to 125 gal. per wash
Pail Milkers 30 to 40 gal. per wash
Miscellaneous Equipment 30 gal. per day
Cow Prep Wash  
Automatic 1 to 4.5 gal. per wash per cow
Manual 0.25 to 0.5 gal. per wash per cow
Parlor Floor 40 to 75 gal. per day
Milkhouse floor 10 to 20 gal. per day
Holding Pen (sprinklers) 5 gpm per head
(depending on nozzle size and pressure)

Summary

Dairies under construction or expanding must evaluate their water needs to ensure that a water source is capable of supplying the production needs of the facility. The information provided in this article can aid in that estimation.