• TABLE OF CONTENTS
HIDE
 Copyright
 Units
 Drinking
 Cow washing
 Washing milking equipment and milking...
 Sprinkling and cooling
 Flushing manure
 Draining rainwater from roofs and...
 Recycling wastewater through crop...
 Developing a water budget for the...
 Strategies to minimize water...
 Reference






Group Title: Florida Cooperative Extension Service circular 1091
Title: Water budgets for Florida dairy farms
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00049206/00001
 Material Information
Title: Water budgets for Florida dairy farms
Series Title: Circular
Physical Description: 6 p. : ; 28 cm.
Language: English
Creator: Van Horn, H. H
Florida Cooperative Extension Service
Publisher: University of Florida, Florida Cooperative Extension Service
Place of Publication: Gainesville
Publication Date: 1993
 Subjects
Subject: Dairy cattle -- Water requirements -- Florida   ( lcsh )
Dairy farms -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 5).
Statement of Responsibility: H.H. Van Horn ... et al..
General Note: Title from caption.
General Note: "February 1993."
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00049206
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 27952646

Table of Contents
    Copyright
        Copyright
    Units
        Page 1
    Drinking
        Page 1
    Cow washing
        Page 2
    Washing milking equipment and milking parlor
        Page 2
    Sprinkling and cooling
        Page 2
    Flushing manure
        Page 3
    Draining rainwater from roofs and concrete areas
        Page 3
    Recycling wastewater through crop irrigation
        Page 3
    Developing a water budget for the dairy farm
        Page 4
    Strategies to minimize water usage
        Page 4
    Reference
        Page 5
        Page 6
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida




/0/



/ UNIVERSITY OF

FLORIDA


Circular 1091
February 1993


Florida Cooperative Extension Service



Water Budgets for Florida Dairy Farms'


H. H. Van Horn, D. R. Bray, R. A. Nordstedt, R. A.
C. G. Chambliss, and G. Kidder2

Water use is essential in all dairies. Drinking
water is indispensable for life of cattle: some water is
necessary for cleaning and sanitation procedures;
moderate amounts are important in periods of heat
stress for evaporative cooling of cows to improve
animal production and health; and additional amounts
can be used in labor saving methods to move manure
and clean barns by flushing in properly designed
facilities. Extensive use, however, increases potential
of surface runoff and penetration to the ground water
with possible environmental impacts offsite.
Heightened environmental concerns and need for
resource conservation have caused implementation of
water use permits and other possible regulatory
actions. Thus, it is important to quantify various
essential uses of water on dairy farms, other uses
which are important to management, and consider
whether reuse of some of the water is possible if it is
important to do so. The following are common uses
of water on dairies:

drinking by dairy cattle
cleaning of dairy cows before milking
cleaning of dairy equipment
sprinkling cows for evaporative cooling
flushing manure
irrigating crops grown to recycle nutrients
from manure
irrigating additional crops


Bucklin, A. B. Bottcher, R. N. Gallaher,


The objective of this fact sheet is to provide
estimates of amounts of water commonly used for
various purposes so that water use budgets for dairy
farms can be developed on a per cow and total farm
basis.

UNITS

1 gallon of water = 8.346 Ib
1 cubic ft of water = 7.48 gallons
1 acre = 43,560 sq ft
1 acre-inch of water = 27,152 gallons

Calibration methods to estimate use. If water meters
are not in place to measure gallons pumped, it will be
necessary to estimate usage. This can be done by
capturing flow through various water lines for
specified times and multiplying by the time water is
flowing through those lines each day.

DRINKING

Table 1 provides estimates of drinking water
requirements in gallons per cow per day. Con-
sumption of about 25 gallons of water per day by
lactating cows is common with variation depending on
milk yield, dry matter intake, temperature, and other
environmental conditions.


1. This document is Circular 1091, Dairy Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences,
University of Florida. Publication date: February 1993.
2. Professor Dairy Science, Extension Agent III Dairy Science, Professor Agricultural Engineering, Associate Professor Agricultural Engineering,
Professor Agricultural Engineering, Professor Agronomy, Associate Professor Agronomy, Professor Soil and Water Science. Cooperative
Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap,
or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean

UI:!'T7 ITY OF FLORIDA LIBRARIES




/0/



/ UNIVERSITY OF

FLORIDA


Circular 1091
February 1993


Florida Cooperative Extension Service



Water Budgets for Florida Dairy Farms'


H. H. Van Horn, D. R. Bray, R. A. Nordstedt, R. A.
C. G. Chambliss, and G. Kidder2

Water use is essential in all dairies. Drinking
water is indispensable for life of cattle: some water is
necessary for cleaning and sanitation procedures;
moderate amounts are important in periods of heat
stress for evaporative cooling of cows to improve
animal production and health; and additional amounts
can be used in labor saving methods to move manure
and clean barns by flushing in properly designed
facilities. Extensive use, however, increases potential
of surface runoff and penetration to the ground water
with possible environmental impacts offsite.
Heightened environmental concerns and need for
resource conservation have caused implementation of
water use permits and other possible regulatory
actions. Thus, it is important to quantify various
essential uses of water on dairy farms, other uses
which are important to management, and consider
whether reuse of some of the water is possible if it is
important to do so. The following are common uses
of water on dairies:

drinking by dairy cattle
cleaning of dairy cows before milking
cleaning of dairy equipment
sprinkling cows for evaporative cooling
flushing manure
irrigating crops grown to recycle nutrients
from manure
irrigating additional crops


Bucklin, A. B. Bottcher, R. N. Gallaher,


The objective of this fact sheet is to provide
estimates of amounts of water commonly used for
various purposes so that water use budgets for dairy
farms can be developed on a per cow and total farm
basis.

UNITS

1 gallon of water = 8.346 Ib
1 cubic ft of water = 7.48 gallons
1 acre = 43,560 sq ft
1 acre-inch of water = 27,152 gallons

Calibration methods to estimate use. If water meters
are not in place to measure gallons pumped, it will be
necessary to estimate usage. This can be done by
capturing flow through various water lines for
specified times and multiplying by the time water is
flowing through those lines each day.

DRINKING

Table 1 provides estimates of drinking water
requirements in gallons per cow per day. Con-
sumption of about 25 gallons of water per day by
lactating cows is common with variation depending on
milk yield, dry matter intake, temperature, and other
environmental conditions.


1. This document is Circular 1091, Dairy Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences,
University of Florida. Publication date: February 1993.
2. Professor Dairy Science, Extension Agent III Dairy Science, Professor Agricultural Engineering, Associate Professor Agricultural Engineering,
Professor Agricultural Engineering, Professor Agronomy, Associate Professor Agronomy, Professor Soil and Water Science. Cooperative
Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap,
or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean

UI:!'T7 ITY OF FLORIDA LIBRARIES







Water Budgets for Florida Dairy Farms


Table 1. Predicted daily water intake of dairy cattle as influenced by milk yield, dry matter intake (DMI), and season.1'2

Cool season (e.g., Feb) Warm. season (e.g., Aug)
Milk yield DMI Water intake DMI Water Intake
(Ib) (Ib) (gal) (Ib) (gal)
0 25 11.5 25 16.3
60 45 22.2 44 26.8
100 55 28.6 48 31.9
1Drinking water intake predicted from equation of Murphy et al. (J. Dairy Sci. 66:35. 1983): Water intake (Ib/day) = 35.2 x
DMI (Ib/day) + .90 x milk produced (Ib/day) + .11 x sodium intake (grams/day) + 2.64 x weekly mean minimum
temperature (0C = (OF 32) x 5/9). For examples above, diet dry matter was assumed to contain .35% Na. Predicted
water intakes (Ib) from formula calculations were divided by 8.346 Ib water/gallon to convert to gallons.

2Average minimum monthly temperatures for February (43.5 F) and August (71 F) used with prediction equation were 70-
yr averages for specified months at Gainesville, FL (Whitty et al., Agronomy Dept., Univ. FL, 1991).


10 1

loq l
SItcS COW WASHING

Currently most dairies in warm climates bring
cows to be milked into a holding area equipped with
floor-level sprinklers which spray water upward to
wash cows. Cows usually have about 15 square feet
per cow and typically are washed for 3 minutes.
Amount of water used per cow should be calculated
for each dairy. An estimate for conservative use is
that a holding area for 300 cows is 30 ft x 150 ft (15
sq ft per cow) and is equipped with sprinklers with 5
ft spacing (say 7 across and 30 rows) giving 210
sprinklers. If each sprinkler applies 5 gallons per
minute, total usage is 1,050 gal/min or 3,150 gal for 3
min; average per cow would be 3,150/300 = 10.5
gal/cow/wash cycle. If cows are milked 3X this would
require 31.5 gal/cow/day.

The washing system previously described also
helps in cooling cows while they are crowded together
waiting to be milked. However, the cooling effect
could be accomplished with less water sprinkled from
above, alternating with fans to give evaporative
cooling, if cows were clean enough so that extensive
washing would not be necessary and if water conser-
vation where necessary.

WASHING MILKING EQUIPMENT AND
MILKING PARLOR

Use of water for these purposes is not as directly
related to the number of cows as are uses for many
other purposes. For washing milking equipment, a
common wash vat volume is 75 gal. If this is filled for
rinse, wash, acid rinse, and sanitizer at each of three


milkings, this amounts to 900 gal for the herd, e.g.
with 300 cows, only 3 gal/cow/day. This is an ex-
tremely small component of the total water budget.
The amount used to wash out the milking parlor is
more variable. If hoses only are used, the amount may
be as little as 2 gal/cow/milking or 6 gal/cow/day if
cows are milked 3X. If flush tanks are used, the
amount may be more nearly 3,000 gal/milking or
9,000 gal/day for 3X, equivalent to 30 gal/cow/day for
a 300-cow system.

SPRINKLING AND COOLING

Sprinklers along with fans are used for
evaporative cooling to relieve heat stress in dairy cows
in hot periods of the year. Their use has shown
increased cow comfort (lowered body temperature
and respiration rates) and economic increases in milk
production and reproductive performance.
Application rates used by dairymen who have adopted
this practice vary. Recent Florida experiments com-
pared application rates of 51, 88, and 108 gal/cow/day
at 10 psi in one experiment and 13, 25 and 40
gal/cow/day in another experiment. The 13
gal/cow/day is close to the estimated evaporation rate
from the cow and surrounding floors. This component
should be considered in water use but not in runoff
water that must be managed in the manure
management system. At this time, we are estimating
25 gal/cow/day as the minimum practical application
rate in order to get adequate coverage of cows to cool
them because often they are not in the sprinkled area.
Total days per year for application may vary from 120
to 240 days. A separate water well, or reserve tank


Page 2







Water Budgets for Florida Dairy Farms


Table 1. Predicted daily water intake of dairy cattle as influenced by milk yield, dry matter intake (DMI), and season.1'2

Cool season (e.g., Feb) Warm. season (e.g., Aug)
Milk yield DMI Water intake DMI Water Intake
(Ib) (Ib) (gal) (Ib) (gal)
0 25 11.5 25 16.3
60 45 22.2 44 26.8
100 55 28.6 48 31.9
1Drinking water intake predicted from equation of Murphy et al. (J. Dairy Sci. 66:35. 1983): Water intake (Ib/day) = 35.2 x
DMI (Ib/day) + .90 x milk produced (Ib/day) + .11 x sodium intake (grams/day) + 2.64 x weekly mean minimum
temperature (0C = (OF 32) x 5/9). For examples above, diet dry matter was assumed to contain .35% Na. Predicted
water intakes (Ib) from formula calculations were divided by 8.346 Ib water/gallon to convert to gallons.

2Average minimum monthly temperatures for February (43.5 F) and August (71 F) used with prediction equation were 70-
yr averages for specified months at Gainesville, FL (Whitty et al., Agronomy Dept., Univ. FL, 1991).


10 1

loq l
SItcS COW WASHING

Currently most dairies in warm climates bring
cows to be milked into a holding area equipped with
floor-level sprinklers which spray water upward to
wash cows. Cows usually have about 15 square feet
per cow and typically are washed for 3 minutes.
Amount of water used per cow should be calculated
for each dairy. An estimate for conservative use is
that a holding area for 300 cows is 30 ft x 150 ft (15
sq ft per cow) and is equipped with sprinklers with 5
ft spacing (say 7 across and 30 rows) giving 210
sprinklers. If each sprinkler applies 5 gallons per
minute, total usage is 1,050 gal/min or 3,150 gal for 3
min; average per cow would be 3,150/300 = 10.5
gal/cow/wash cycle. If cows are milked 3X this would
require 31.5 gal/cow/day.

The washing system previously described also
helps in cooling cows while they are crowded together
waiting to be milked. However, the cooling effect
could be accomplished with less water sprinkled from
above, alternating with fans to give evaporative
cooling, if cows were clean enough so that extensive
washing would not be necessary and if water conser-
vation where necessary.

WASHING MILKING EQUIPMENT AND
MILKING PARLOR

Use of water for these purposes is not as directly
related to the number of cows as are uses for many
other purposes. For washing milking equipment, a
common wash vat volume is 75 gal. If this is filled for
rinse, wash, acid rinse, and sanitizer at each of three


milkings, this amounts to 900 gal for the herd, e.g.
with 300 cows, only 3 gal/cow/day. This is an ex-
tremely small component of the total water budget.
The amount used to wash out the milking parlor is
more variable. If hoses only are used, the amount may
be as little as 2 gal/cow/milking or 6 gal/cow/day if
cows are milked 3X. If flush tanks are used, the
amount may be more nearly 3,000 gal/milking or
9,000 gal/day for 3X, equivalent to 30 gal/cow/day for
a 300-cow system.

SPRINKLING AND COOLING

Sprinklers along with fans are used for
evaporative cooling to relieve heat stress in dairy cows
in hot periods of the year. Their use has shown
increased cow comfort (lowered body temperature
and respiration rates) and economic increases in milk
production and reproductive performance.
Application rates used by dairymen who have adopted
this practice vary. Recent Florida experiments com-
pared application rates of 51, 88, and 108 gal/cow/day
at 10 psi in one experiment and 13, 25 and 40
gal/cow/day in another experiment. The 13
gal/cow/day is close to the estimated evaporation rate
from the cow and surrounding floors. This component
should be considered in water use but not in runoff
water that must be managed in the manure
management system. At this time, we are estimating
25 gal/cow/day as the minimum practical application
rate in order to get adequate coverage of cows to cool
them because often they are not in the sprinkled area.
Total days per year for application may vary from 120
to 240 days. A separate water well, or reserve tank


Page 2







Water Budgets for Florida Dairy Farms


Table 1. Predicted daily water intake of dairy cattle as influenced by milk yield, dry matter intake (DMI), and season.1'2

Cool season (e.g., Feb) Warm. season (e.g., Aug)
Milk yield DMI Water intake DMI Water Intake
(Ib) (Ib) (gal) (Ib) (gal)
0 25 11.5 25 16.3
60 45 22.2 44 26.8
100 55 28.6 48 31.9
1Drinking water intake predicted from equation of Murphy et al. (J. Dairy Sci. 66:35. 1983): Water intake (Ib/day) = 35.2 x
DMI (Ib/day) + .90 x milk produced (Ib/day) + .11 x sodium intake (grams/day) + 2.64 x weekly mean minimum
temperature (0C = (OF 32) x 5/9). For examples above, diet dry matter was assumed to contain .35% Na. Predicted
water intakes (Ib) from formula calculations were divided by 8.346 Ib water/gallon to convert to gallons.

2Average minimum monthly temperatures for February (43.5 F) and August (71 F) used with prediction equation were 70-
yr averages for specified months at Gainesville, FL (Whitty et al., Agronomy Dept., Univ. FL, 1991).


10 1

loq l
SItcS COW WASHING

Currently most dairies in warm climates bring
cows to be milked into a holding area equipped with
floor-level sprinklers which spray water upward to
wash cows. Cows usually have about 15 square feet
per cow and typically are washed for 3 minutes.
Amount of water used per cow should be calculated
for each dairy. An estimate for conservative use is
that a holding area for 300 cows is 30 ft x 150 ft (15
sq ft per cow) and is equipped with sprinklers with 5
ft spacing (say 7 across and 30 rows) giving 210
sprinklers. If each sprinkler applies 5 gallons per
minute, total usage is 1,050 gal/min or 3,150 gal for 3
min; average per cow would be 3,150/300 = 10.5
gal/cow/wash cycle. If cows are milked 3X this would
require 31.5 gal/cow/day.

The washing system previously described also
helps in cooling cows while they are crowded together
waiting to be milked. However, the cooling effect
could be accomplished with less water sprinkled from
above, alternating with fans to give evaporative
cooling, if cows were clean enough so that extensive
washing would not be necessary and if water conser-
vation where necessary.

WASHING MILKING EQUIPMENT AND
MILKING PARLOR

Use of water for these purposes is not as directly
related to the number of cows as are uses for many
other purposes. For washing milking equipment, a
common wash vat volume is 75 gal. If this is filled for
rinse, wash, acid rinse, and sanitizer at each of three


milkings, this amounts to 900 gal for the herd, e.g.
with 300 cows, only 3 gal/cow/day. This is an ex-
tremely small component of the total water budget.
The amount used to wash out the milking parlor is
more variable. If hoses only are used, the amount may
be as little as 2 gal/cow/milking or 6 gal/cow/day if
cows are milked 3X. If flush tanks are used, the
amount may be more nearly 3,000 gal/milking or
9,000 gal/day for 3X, equivalent to 30 gal/cow/day for
a 300-cow system.

SPRINKLING AND COOLING

Sprinklers along with fans are used for
evaporative cooling to relieve heat stress in dairy cows
in hot periods of the year. Their use has shown
increased cow comfort (lowered body temperature
and respiration rates) and economic increases in milk
production and reproductive performance.
Application rates used by dairymen who have adopted
this practice vary. Recent Florida experiments com-
pared application rates of 51, 88, and 108 gal/cow/day
at 10 psi in one experiment and 13, 25 and 40
gal/cow/day in another experiment. The 13
gal/cow/day is close to the estimated evaporation rate
from the cow and surrounding floors. This component
should be considered in water use but not in runoff
water that must be managed in the manure
management system. At this time, we are estimating
25 gal/cow/day as the minimum practical application
rate in order to get adequate coverage of cows to cool
them because often they are not in the sprinkled area.
Total days per year for application may vary from 120
to 240 days. A separate water well, or reserve tank


Page 2







Water Budgets for Florida Dairy Farms


and booster pump, may be needed to supply short
term high demand needed by the sprinkler system.

FLUSHING MANURE

If facilities are designed with concrete floors with
enough slope so water flow propelled by gravity can
be used to move manure, flushing is a clean and labor
saving method to move manure. Amounts used on a
per cow basis vary widely depending on size and
design of facilities and frequency of flushing. Amounts
need to be calculated for each farm. However, usually
a flush of about 3,000 gal is needed to clean an alley
width of 10 to 16 ft. If four alleys are common for
every 400 cows and alleys are flushed twice daily, this
would be an average use of 60 gal/cow/day. Many
dairies use more flushings per day.

DRAINING RAINWATER FROM ROOFS AND
CONCRETE AREAS

Rainwater entering wastewater holding areas can
be a significant quantity on many dairies. For the
example dairy representing typical minimum water
usage with a flush system (Table 4), the net
accumulation during the hot season (also the wet
season in Florida) was calculated as follows: assumed
wastewater holding area is one acre surface area/100
cows, net rainfall accumulation in holding area is 3
inches more than evaporation per month, concrete
areas and/or undiverted roof areas that capture
rainfall are 15,000 sq ft/100 cows that divert
15,000/43,560 sq ft per acre of the 3 inches to the
wastewater holding facility. Thus, 3 inches plus 0.344
x 3 = 4.03 acre-inches per month or essentially 1.0
acre-inch per week/100 cows (approximately 27,000
gallons/100 cows).

RECYCLING WASTEWATER THROUGH
CROP IRRIGATION

Most often nitrogen is the nutrient on which
manure application rates are budgeted. To maximize
nutrient uptake, crop growth should be as vigorous as
possible. This requires irrigation during most of the
year in Florida. Thus, disposal of flushed wastewater
can be accomplished through an irrigation system that
also serves to apply additional amounts of irrigation
water to optimize the nutrient recycling. In southern
regions, multiple cropping systems are possible which
will recycle effectively nitrogen excretions from 100
cows on a sprayfield or manure application field of
about 30 acres (see Van Horn et al., IFAS Circular
1016).


Tentative estimates of total water needs of the
growing crops average about 1.75 inches of water per
week (.25 inches per day) from irrigation plus rainfall
with a minimum of .5 inches per week tolerated even
in rainy season on sandy soils. The basis for this
follows.

Florida receives 50 to 60 inches of water per year
from natural rainfall. This amount of rainfall could
provide much of the water required to produce
relatively good yields for crops to grow continuously
12 months out of the year. However, most of this
water comes during the summer months so that
distribution is inadequate for good utilization.
Estimated total water requirements for two triple
cropping forage systems are shown in Table 2. These
total water requirements were developed from the
estimated amount of water required per unit of dry
matter produced for different crops and estimates of
dry matter yield.

Another problem with utilization of either rainfall
or irrigation water is the sandy texture of most
Florida soils. Sands will only hold small amounts of
water for crop use at any one time. The sandy soils of
north central Florida will likely only hold about 1.0
inch of water per foot of soil depth. This amount
would be higher in the clayey soils of northwest
Florida, maybe about 1.5 to 1.75 inches per foot of
soil depth. Therefore, when we have large amounts of
rainfall some may run off the soil surface, some is
evaporated, some percolates through the soil quickly,
and very little is held for crop use. From research and
personal experience, it has been estimated that 8 to
10 inches of extra irrigation water are needed above
rainfall to net the total 20 to 25 inches required to
grow a corn crop.

There is limited information on water use for
multiple cropping. Data suggest spring corn could
require 8 to 14 inches of irrigation and the fall crop
slightly less. If 6 to 8 inches were applied to
supplement rainfall for winter wheat or rye, then for
triple cropping systems of wheat-corn-corn or rye-
corn-forage sorghum one might need total supple-
mental irrigation in the range of 25 to 35 acre-inches
per year. These estimates are for efficient utilization
of water.


Page 3







Water Budgets for Florida Dairy Farms


and booster pump, may be needed to supply short
term high demand needed by the sprinkler system.

FLUSHING MANURE

If facilities are designed with concrete floors with
enough slope so water flow propelled by gravity can
be used to move manure, flushing is a clean and labor
saving method to move manure. Amounts used on a
per cow basis vary widely depending on size and
design of facilities and frequency of flushing. Amounts
need to be calculated for each farm. However, usually
a flush of about 3,000 gal is needed to clean an alley
width of 10 to 16 ft. If four alleys are common for
every 400 cows and alleys are flushed twice daily, this
would be an average use of 60 gal/cow/day. Many
dairies use more flushings per day.

DRAINING RAINWATER FROM ROOFS AND
CONCRETE AREAS

Rainwater entering wastewater holding areas can
be a significant quantity on many dairies. For the
example dairy representing typical minimum water
usage with a flush system (Table 4), the net
accumulation during the hot season (also the wet
season in Florida) was calculated as follows: assumed
wastewater holding area is one acre surface area/100
cows, net rainfall accumulation in holding area is 3
inches more than evaporation per month, concrete
areas and/or undiverted roof areas that capture
rainfall are 15,000 sq ft/100 cows that divert
15,000/43,560 sq ft per acre of the 3 inches to the
wastewater holding facility. Thus, 3 inches plus 0.344
x 3 = 4.03 acre-inches per month or essentially 1.0
acre-inch per week/100 cows (approximately 27,000
gallons/100 cows).

RECYCLING WASTEWATER THROUGH
CROP IRRIGATION

Most often nitrogen is the nutrient on which
manure application rates are budgeted. To maximize
nutrient uptake, crop growth should be as vigorous as
possible. This requires irrigation during most of the
year in Florida. Thus, disposal of flushed wastewater
can be accomplished through an irrigation system that
also serves to apply additional amounts of irrigation
water to optimize the nutrient recycling. In southern
regions, multiple cropping systems are possible which
will recycle effectively nitrogen excretions from 100
cows on a sprayfield or manure application field of
about 30 acres (see Van Horn et al., IFAS Circular
1016).


Tentative estimates of total water needs of the
growing crops average about 1.75 inches of water per
week (.25 inches per day) from irrigation plus rainfall
with a minimum of .5 inches per week tolerated even
in rainy season on sandy soils. The basis for this
follows.

Florida receives 50 to 60 inches of water per year
from natural rainfall. This amount of rainfall could
provide much of the water required to produce
relatively good yields for crops to grow continuously
12 months out of the year. However, most of this
water comes during the summer months so that
distribution is inadequate for good utilization.
Estimated total water requirements for two triple
cropping forage systems are shown in Table 2. These
total water requirements were developed from the
estimated amount of water required per unit of dry
matter produced for different crops and estimates of
dry matter yield.

Another problem with utilization of either rainfall
or irrigation water is the sandy texture of most
Florida soils. Sands will only hold small amounts of
water for crop use at any one time. The sandy soils of
north central Florida will likely only hold about 1.0
inch of water per foot of soil depth. This amount
would be higher in the clayey soils of northwest
Florida, maybe about 1.5 to 1.75 inches per foot of
soil depth. Therefore, when we have large amounts of
rainfall some may run off the soil surface, some is
evaporated, some percolates through the soil quickly,
and very little is held for crop use. From research and
personal experience, it has been estimated that 8 to
10 inches of extra irrigation water are needed above
rainfall to net the total 20 to 25 inches required to
grow a corn crop.

There is limited information on water use for
multiple cropping. Data suggest spring corn could
require 8 to 14 inches of irrigation and the fall crop
slightly less. If 6 to 8 inches were applied to
supplement rainfall for winter wheat or rye, then for
triple cropping systems of wheat-corn-corn or rye-
corn-forage sorghum one might need total supple-
mental irrigation in the range of 25 to 35 acre-inches
per year. These estimates are for efficient utilization
of water.


Page 3







Water Budgets for Florida Dairy Farms


and booster pump, may be needed to supply short
term high demand needed by the sprinkler system.

FLUSHING MANURE

If facilities are designed with concrete floors with
enough slope so water flow propelled by gravity can
be used to move manure, flushing is a clean and labor
saving method to move manure. Amounts used on a
per cow basis vary widely depending on size and
design of facilities and frequency of flushing. Amounts
need to be calculated for each farm. However, usually
a flush of about 3,000 gal is needed to clean an alley
width of 10 to 16 ft. If four alleys are common for
every 400 cows and alleys are flushed twice daily, this
would be an average use of 60 gal/cow/day. Many
dairies use more flushings per day.

DRAINING RAINWATER FROM ROOFS AND
CONCRETE AREAS

Rainwater entering wastewater holding areas can
be a significant quantity on many dairies. For the
example dairy representing typical minimum water
usage with a flush system (Table 4), the net
accumulation during the hot season (also the wet
season in Florida) was calculated as follows: assumed
wastewater holding area is one acre surface area/100
cows, net rainfall accumulation in holding area is 3
inches more than evaporation per month, concrete
areas and/or undiverted roof areas that capture
rainfall are 15,000 sq ft/100 cows that divert
15,000/43,560 sq ft per acre of the 3 inches to the
wastewater holding facility. Thus, 3 inches plus 0.344
x 3 = 4.03 acre-inches per month or essentially 1.0
acre-inch per week/100 cows (approximately 27,000
gallons/100 cows).

RECYCLING WASTEWATER THROUGH
CROP IRRIGATION

Most often nitrogen is the nutrient on which
manure application rates are budgeted. To maximize
nutrient uptake, crop growth should be as vigorous as
possible. This requires irrigation during most of the
year in Florida. Thus, disposal of flushed wastewater
can be accomplished through an irrigation system that
also serves to apply additional amounts of irrigation
water to optimize the nutrient recycling. In southern
regions, multiple cropping systems are possible which
will recycle effectively nitrogen excretions from 100
cows on a sprayfield or manure application field of
about 30 acres (see Van Horn et al., IFAS Circular
1016).


Tentative estimates of total water needs of the
growing crops average about 1.75 inches of water per
week (.25 inches per day) from irrigation plus rainfall
with a minimum of .5 inches per week tolerated even
in rainy season on sandy soils. The basis for this
follows.

Florida receives 50 to 60 inches of water per year
from natural rainfall. This amount of rainfall could
provide much of the water required to produce
relatively good yields for crops to grow continuously
12 months out of the year. However, most of this
water comes during the summer months so that
distribution is inadequate for good utilization.
Estimated total water requirements for two triple
cropping forage systems are shown in Table 2. These
total water requirements were developed from the
estimated amount of water required per unit of dry
matter produced for different crops and estimates of
dry matter yield.

Another problem with utilization of either rainfall
or irrigation water is the sandy texture of most
Florida soils. Sands will only hold small amounts of
water for crop use at any one time. The sandy soils of
north central Florida will likely only hold about 1.0
inch of water per foot of soil depth. This amount
would be higher in the clayey soils of northwest
Florida, maybe about 1.5 to 1.75 inches per foot of
soil depth. Therefore, when we have large amounts of
rainfall some may run off the soil surface, some is
evaporated, some percolates through the soil quickly,
and very little is held for crop use. From research and
personal experience, it has been estimated that 8 to
10 inches of extra irrigation water are needed above
rainfall to net the total 20 to 25 inches required to
grow a corn crop.

There is limited information on water use for
multiple cropping. Data suggest spring corn could
require 8 to 14 inches of irrigation and the fall crop
slightly less. If 6 to 8 inches were applied to
supplement rainfall for winter wheat or rye, then for
triple cropping systems of wheat-corn-corn or rye-
corn-forage sorghum one might need total supple-
mental irrigation in the range of 25 to 35 acre-inches
per year. These estimates are for efficient utilization
of water.


Page 3







Water Budgets for Florida Dairy Farms


Table 2. Crop yield and water requirement estimates for two triple cropping forage systems.1
Silage yield Water required
Crop Ton/A Ton/A Ib/A Ib/ Ib/A gal/A A-inch
No Name 35% DM DM DM Ib DM total total total
1 Wheat 10 3.5 7,000 500 3,500,000 419,362 15.4
2 Corn 24 8.4 16,800 368 6,182,400 740,762 27.3
3 Corn 14 4.9 9,800 368 3,606,400 432,111 15.9
TOTAL 48 16.8 33,600 13,288,800 1,592,235 58.6
1 Rye 10 3.5 7,000 500 3,500,000 419,362 15.4
2 Corn 24 8.4 16,800 368 6,182,400 740,762 27.3
3 F. Sorghum 18 6.3 12,600 271 3,414,600 409,130 15.1
TOTAL 52 18.2 36,400 13,097,000 1,569,254 57.8

'A = acre, No = number, DM = dry matter.


Limited data are available on the maximum
amount of water that could be applied and not reduce
yield or quality of forage and not result in pollution of
ground water with nitrates and other minerals.
However, the maximum probably is at least 35 to 45
inches per year above the minimum acre-inch totals
previously discussed if distributed adequately
throughout the cropping cycles and if nitrogen
concentrations are not too high.

Table 3 utilizes previous logic to estimate water
use per week in a triple cropping program which
would maximize fertilization with manure nutrients.
Average weekly use of water by triple cropping is
about 1.75 inches per week.

DEVELOPING A WATER BUDGET FOR THE
DAIRY FARM

A wide range exists in amount of water usage on
dairy farms. If the dairy waste management system
was designed to utilize flushed manure nutrients
through cropping systems grown under irrigation, the
water used at the dairy should be reused through
irrigation. If water amounts are small in relation to
irrigation needs for crop production, liberal use of
water for cow washing, cow cooling, and manure
flushing is not a use problem. Costs for construction
of storage structures for holding wastewater until used
for irrigation may warrant consideration. The example
water use budgets shown in Table 4 illustrate that
water usage on dairies is probably small in compari-
son to irrigation needs when there are 30 acres of
sprayfield/100 cows. Conversely, the amounts used in
most Florida dairy systems would be large and


unmanageable if application through irrigation is not
an option or if less acreage for irrigation is available
than needed for application of all manure nutrients.

If a dairy does not have acreage available close by
to utilize manure nutrients and water through an
environmentally accountable sprayfield application
system, it will be necessary to export nutrients off the
farm, preferably as solid wastes to avoid excessive
hauling or pumping costs. Under these conditions it
will be important to exclude as much water as
possible from the manure management system. If the
water and manure nutrients cannot be used through
irrigation, a non-flush system should be utilized.
However, usually some irrigation is possible,
permitting dairymen to scrape and haul manure from
some areas such as feeding lanes before the lanes are
flushed for further cleanup.

STRATEGIES TO MINIMIZE WATER USAGE

Table 4 presents one column indicating a
theoretical minimum amount of water use on a dairy.
This system implies that cows are clean enough and
cool enough that sprinkler washers are not needed to
clean and cool cows while being held for milking.
Also, it is assumed that all of the manure is scraped
and hauled to manure disposal fields or transported
off the dairy in some other fashion. Intermediate
steps that might be taken include:

* Scraping and hauling manure from high use areas
such as the feeding barn so that this manure can
be managed off the dairy.


Page 4







Water Budgets for Florida Dairy Farms


Table 2. Crop yield and water requirement estimates for two triple cropping forage systems.1
Silage yield Water required
Crop Ton/A Ton/A Ib/A Ib/ Ib/A gal/A A-inch
No Name 35% DM DM DM Ib DM total total total
1 Wheat 10 3.5 7,000 500 3,500,000 419,362 15.4
2 Corn 24 8.4 16,800 368 6,182,400 740,762 27.3
3 Corn 14 4.9 9,800 368 3,606,400 432,111 15.9
TOTAL 48 16.8 33,600 13,288,800 1,592,235 58.6
1 Rye 10 3.5 7,000 500 3,500,000 419,362 15.4
2 Corn 24 8.4 16,800 368 6,182,400 740,762 27.3
3 F. Sorghum 18 6.3 12,600 271 3,414,600 409,130 15.1
TOTAL 52 18.2 36,400 13,097,000 1,569,254 57.8

'A = acre, No = number, DM = dry matter.


Limited data are available on the maximum
amount of water that could be applied and not reduce
yield or quality of forage and not result in pollution of
ground water with nitrates and other minerals.
However, the maximum probably is at least 35 to 45
inches per year above the minimum acre-inch totals
previously discussed if distributed adequately
throughout the cropping cycles and if nitrogen
concentrations are not too high.

Table 3 utilizes previous logic to estimate water
use per week in a triple cropping program which
would maximize fertilization with manure nutrients.
Average weekly use of water by triple cropping is
about 1.75 inches per week.

DEVELOPING A WATER BUDGET FOR THE
DAIRY FARM

A wide range exists in amount of water usage on
dairy farms. If the dairy waste management system
was designed to utilize flushed manure nutrients
through cropping systems grown under irrigation, the
water used at the dairy should be reused through
irrigation. If water amounts are small in relation to
irrigation needs for crop production, liberal use of
water for cow washing, cow cooling, and manure
flushing is not a use problem. Costs for construction
of storage structures for holding wastewater until used
for irrigation may warrant consideration. The example
water use budgets shown in Table 4 illustrate that
water usage on dairies is probably small in compari-
son to irrigation needs when there are 30 acres of
sprayfield/100 cows. Conversely, the amounts used in
most Florida dairy systems would be large and


unmanageable if application through irrigation is not
an option or if less acreage for irrigation is available
than needed for application of all manure nutrients.

If a dairy does not have acreage available close by
to utilize manure nutrients and water through an
environmentally accountable sprayfield application
system, it will be necessary to export nutrients off the
farm, preferably as solid wastes to avoid excessive
hauling or pumping costs. Under these conditions it
will be important to exclude as much water as
possible from the manure management system. If the
water and manure nutrients cannot be used through
irrigation, a non-flush system should be utilized.
However, usually some irrigation is possible,
permitting dairymen to scrape and haul manure from
some areas such as feeding lanes before the lanes are
flushed for further cleanup.

STRATEGIES TO MINIMIZE WATER USAGE

Table 4 presents one column indicating a
theoretical minimum amount of water use on a dairy.
This system implies that cows are clean enough and
cool enough that sprinkler washers are not needed to
clean and cool cows while being held for milking.
Also, it is assumed that all of the manure is scraped
and hauled to manure disposal fields or transported
off the dairy in some other fashion. Intermediate
steps that might be taken include:

* Scraping and hauling manure from high use areas
such as the feeding barn so that this manure can
be managed off the dairy.


Page 4







Water Budgets for Florida Dairy Farms


Table 3. Average daily and weekly water used by triple cropping systems based on crop water use and rainfall assumptions.
All values are in inches.


Irrigated water
needed to triple Estimated yearly Average weekly
crop rainfall Total water Average daily water water
20 50 70 .19 1.34
25 50 75 .21 1.44
30 50 80 .22 1.53
35 50 85 .23 1.63
40 50 90 .24 1.73
45 50 95 .26 1.82
20 55 75 .21 1.44
25 55 80 .22 1.53
30 55 85 .23 1.63
35 55 90 .24 1.73
40 55 95 .26 1.82
45 55 100 .27 1.92
20 60 80 .22 1.53
25 60 85 .23 1.63
30 60 90 .24 1.73
35 60 95 .26 1.82
40 60 100 .27 1.92
45 60 105 .29 2.01


* Using wastewater rather than fresh water to flush
manure from feeding areas and freestall barns.

Using a housing system that will keep cows clean
enough so that cow washers are not needed to
clean cows before milking. This system, however,
may require use of alternating sprinklers and fans
to keep crowded cows cool during hot weather.

If flushing is desired in conjunction with scraping and
hauling from heavy use areas, perhaps the feeding
area could be flushed with recycled water after
scraping to clean the area. These procedures would
reduce total nutrient loads retained in wastewater and
would significantly reduce the size of the sprayfield
needed for water and manure nutrient recycling.

SUGGESTED REFERENCES

Beede, D. K. 1992. Water for dairy cattle. Pages 260-
271 in Large Dairy Herd Management, American
Dairy Science Assoc., Champaign, IL.


Bray, D. R., D. K. Beede, R. A. Bucklin, and G. L.
Hahn. 1992. Cooling, shade, and sprinkling. Pages
655-663 in Large Dairy Herd Management,
American Dairy Science Assoc., Champaign, IL.

North Florida Research and Education Center. 1977.
AREC Research Report 77-2, IFAS, Univ.
Florida, Gainesville.

Van Horn, H. H., R. A. Nordstedt, A. V. Bottcher, E.
A. Hanlon, D. A. Graetz, and C. F. Chambliss.
1991. Dairy Manure Management: Strateties for
recycling nutrients to recover fertilizer value and
avoid environmental pollution. Circular 1016,
Florida Coop. Ext., Univ. Florida, Gainesville.

Wesley, W. K. 1979. Inigated corn production and
moisture management. Bul. 820, Coop. Ext. Serv.,
Univ. Georgia College of Agric. and USDA.


Page 5







Water Budgets for Florida Dairy Farms


Table 4. Estimated water budgets for three example dairies. All values are gallons unless otherwise noted.

Flush systems Non-flush

Water use in the dairy Typical need Common usage Theoretical Worksheet for
during hot season on some dairies minimum your dairy

Drinking (cows) 25 25 25
Cleaning cows 32 150 0

Cleaning milking equipment 3 5 3

Cleaning milking parlor 30 30 6

Sprinklers for cooling 25 130 12
Flushing manure 60 80 0

Total use/cow/day 175 400 46

Total use/100 cows/day 17,500 40,000 4,600

Use/100 cows/week 122,500 280,000 32,200

Water in milk/100 cows/week 4,500 4,500 4,500

Estimated evaporation (@20% of 24,500 56,000 6,440
use)

Average rainfall and watershed 27,000 27,000 13,000
drainage into storage facility/100
cows/week

Wastewater produced from 120,500 246,500 38,760
100 cows/week
Acre-inches/100 cows/week 4.44 9.08 1.43

Inches/week if 30 acres in .15 .30 .05
sprayfield
Example calculations (column 1):
Total use/cow/day = 175 gal
Total use/100 cows/wk = 122,500 gal less 4,500 in milk and 24,500 gal evaporation = 93,500 gal/wk
Net rainfall and watershed drainage to storage/100 cows/wk = 27,000
Acre inches/100 cows/wk = (93,500 + 27,000)/27,152 gal per acre-inch = 4.44

If 30 acres were in sprayfield, 4.44/30 = .15 inches/wk

If crop needed 1.75 acre-inches/wk (a common average), a total of 1.75 inches x 30 acres x 27,152 gal/acre-inch =
1,425,480 gal is needed of which only 120,500 gallons (8.5%) would come from dairy wastewater. The remaining
(91.5% of total) would have to come from rainfall or fresh irrigation water.


Page 6




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