2. Introduction Adaptive management
Grass-based dairying is best described as a
Grass-based dairy farming requires a level
method of marketing forage through milk of acumen and observational sophistication
products. Success with grass-based dairy not approached in most conventional farms.
farming requires high-quality pasture and It is critically important that farm employees
livestock adapted to a high-forage diet. develop an appreciation for the rigor of adap-
Related ATTRA Grass-based producers ensure that forages tive management. Adaptive management is
Publications provide the bulk of the energy and protein characterized by:
Cattle Production: needed to produce milk by providing high- • Resource assessment
Considerations for quality pasture during the grazing season • Planned implementation
Pasture-Based Beef and and stored forages in the dormant season.
Dairy Producers • Observation
Supplementation is provided to cattle based
Dairy Farm Sustainability • Adjustment to suit new conditions
Checksheet
primarily on mineral and energy, as high-
quality pasture tends to be high in protein
Dairy Beef
and energy is required to nourish rumen
The Economics of
microorganisms and enable them to metab- Providing high-quality pasture as the
Grass-based Dairying
olize high-protein forages. principle feed source is not simple, as
Dairy Resource List: conditions and situations are always
Organic and Sustainable grass-based dairies utilize changing. Planning for change is key to
Pasture-Based
an ecological approach to health care adaptive management. Conduct a resource
Raising Dairy Heifers by relying on natural immunity that inventory to lay the groundwork for con-
on Pasture
comes with pasture access and exposure tinued adaptive management of the grazing
Value-added
Dairy Options
to increased biodiversity. This is accom- system and overall farm plan. Detailed
plished by developing an agroecosys- information on this important topic is
Ruminant Nutrition
for Graziers tem that displays a high degree of resil- provided later in this publication.
A Brief Overview of
ience; maintains the system in ecological
Nutrient Cycling in balance as much as possible to reduce
Pastures pest and disease pressure; and ensures
New Zealand-style dairying
Assessing the Pasture a high level of balanced nutrition to soil, Ninety percent of the milk produced in New
Soil Resource plants and animals. Developing a low- Zealand is exported at world market prices,
Managed Grazing in input farming strategy that uses natural with no government subsidies or incentives.
Riparian Areas ecological services instead of purchased Feeding grains and concentrates in New
Pasture, Rangeland, and inputs as much as possible also reduces Zealand is 6 to 12 times as costly as grazing.
Grazing Management
production costs. This situation has forced New Zealand pro-
Pastures: Sustainable ducers to be extremely proactive in devel-
Management Grass-based dairies take advantage of oping low-cost production technologies,
Pastures: Going Organic nutrient cycling for soil fertility, keep- and pasture has become the main factor in
Paddock Design, ing nutrients on the farm and completing decreasing farm costs.
Fencing, and Water the soil cycle by supplying natural fer-
Systems for tilizers in manure and urine directly on Some of the tangible benefits of New
Controlled Grazing
the pastures while cattle graze. This level Zealand style grass-based dairying
Rotational Grazing of nutrient management requires strict may include:
NCAT’s Organic attention to pasture management, which • Maximum return to the farmer
Livestock Workbook in grass-based dairies includes rotational
Organic Livestock grazing systems to maximize forage intake • Low cost of feeding, housing,
Documentation Forms
and pasture health. Attention will be manure disposal and machinery
given to grazing management in this pub- • High production per person, ideal
lication, and more detailed information for family dairies
can be found in the ATTRA publications • Flexibility in milking system design
Rotational Grazing, Ruminant Nutrition
for Graziers and Pasture, Rangeland and • Flexibility in grazing system design
Grazing Management. • Increased pasture quality
Page 2 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
3. • Increased water quality in streams have been relying on harvested grain and
• Increased fat and protein in grass- forages to provide high-quality feedstuffs
fed milk products to support enormous milk yields. Mod-
ern Holsteins can produce more than 60
• Cleaner cows (Holmes et al, 2007 pounds of milk per day, and many farms
and GLCI, 2005) report herd averages in excess of 20,000
Switching to grass-based dairy production pounds per lactation.
provides other benefits as well, whether
you choose to milk year-round or season- According to the American Livestock
ally. When you graze cows without feed- Breeds Conservancy, grass-based dairy
ing any concentrates, you can reasonably farming is on the increase, and this neces-
expect a decrease in gross income due to sitates a very different type of animal.
reduced milk production. If the herd is not Low-cost, grass-based dairies often cannot
well adapted to a forage-only diet or pas- support the high nutritional requirements
ture quality is not excellent, it may also be needed by large-framed, high-producing
very difficult to get cows bred back in the cattle. Grass-based dairy producers are
desired calving window. However, produc- utilizing Ayrshire and Jersey breeds for
G
ers in Pennsylvania have noticed a subse- their ability to maintain condition, milk
rass-based
quent decrease in cow cost. Coupled with production and reproduction on forage.
These cattle types are typically smaller and
an increase in cow health and the efficien-
cies of working a herd with fewer persons, framed and have lower nutrient require- seasonal
producers have realized an increase in net ments than Holsteins. Again, there is wide dairies, like all dairy
income, even with reduced milk production variability in the expression of the traits operations, rely on
(GLCI, 2005). However, some dairy farms important for pasture-based systems, even
healthy, fertile cows
have experienced very negative health within dairy breeds. A good example is the
Holstein genetics that are being developed of high genetic value.
impacts due to zero grain feeding before
their herd and their pastures were ready. through selection by grass-based producers
This can result in some disastrous situa- in New Zealand.
tions, so cow nutrition should be closely Grass-based and seasonal dairies, like
observed if transitioning to grass-only all dairy operations, rely on healthy,
feeding to ensure the cows maintain body fertile cows of high genetic value. A
condition, breed back on time and continue cow’s productivity is determined by its
to produce milk sustainably. management, especially feeding, health,
Making a decision to switch to a grass-based and milking, and by its own inher-
system includes a sober look at the weak- ent capabilities including genetic merit
nesses of grazing as well. In addition to low (Holmes et al, 2007). Selection of appro-
productivity, you can reasonably expect a priate animal genetics for grass-based
yearly variability in milk production and systems is therefore an important factor
profitability, as grass-based systems rely in the adaptive management process.
on weather and forage growth to maintain
productivity. In addition, there are the
inherent inefficiencies of seasonal milk sup- Factors influencing genetic merit
ply to processors that should be taken into in dairy cows
account (Holmes et al, 2007). • Milk production potential
• Percent fat and protein
Breeds and animal types • Feed conversion efficiency
The dairy industry in the United States • Health and reproduction traits
has been under very intensive consoli-
• Cow longevity, or the ability to
dation and industrialization pressure to consistently produce large quantities of
maximize the efficiencies that come with milk during a long lifetime of lactations
large-scale production. Since the 1950s (Holmes et al, 2007)
dairy farms have been getting bigger, and
www.attra.ncat.org ATTRA Page 3
4. New Zealand dairy farmers seek to improve production, especially on a farm that relies
genetic merit in cow herds by culling cows on pasture for a significant portion of feed
of inferior merit and replacing them with for high-producing dairy cows. ATTRA
cows of superior genetic merit. Some of the has a dairy sustainability checksheet that
important traits in dairy production, such is designed to stimulate critical thinking in
as milk fat, and protein yields, are herita- planning a farm on which a primary enter-
ble (Holmes et al., 2007). Heritability is a prise is milk production. It contains a series
characteristic of those traits that are suc- of questions intended to stimulate aware-
cessfully transmitted from one generation to ness and define strong areas in your farm
the next. Selecting bulls and cows that have management as well as areas that might be
these heritable traits is the foundation of enhanced. The Dairy Farm Sustainability
improving the genetics of a herd over time. Checksheet can be accessed at www.attra.
Detailed information on using heritabil- org/attra-pub/PDF/dairychecksheet.pdf or
ity for improving the genetic merit of dairy by calling ATTRA at 1-800-346-9140.
herds can be found in Virginia Cooperative Darrell Emmick, a grazing specialist with
Extension’s fact sheet Using Heritability New York National Resources Conservation
for Genetic Improvement, available online Service, has suggested some steps to evalu-
at www.ext.vt.edu/pubs/dairy/404-084/ ate resources when considering a new graz-
404-084.html. ing operation. First, identify your goals.
For more information on livestock breeds, What it is you expect to do and get out of
see the Oklahoma State University Depart- grazing cows? Then, identify problems to
ment of Animal Science Web site at www. overcome and opportunities you can take
ansi.okstate.edu/breeds. Information on advantage of. List your on-farm assets as
rare breeds can be found at the American they are now, such as land, livestock, for-
Livestock Breeds Conservancy Web site at ages, water, lanes, buildings, machinery
www.albc-usa.org. and wildlife (NRAES, 2006a).
When the initial resource inventory is done,
Taking an inventory of match your grazing goals to the resources
resources for grass-based you have on hand to determine the feasibil-
ity of a new transition. Adaptive manage-
dairying ment comes to play as you begin to orient
Taking a total farm asset inventory is the your existing resources to the new grazing
first step in adaptive management. Inven- venture, evaluate successes and problems
tory and monitoring of all aspects of the and adapting to new changes. For detailed
farm are critical for sustainable dairy information on resource inventory, see
chapter three in Managing and Marketing
for Pasture-Based Livestock Production,
published by the National Resource, Agri-
culture and Engineering Service in 2006
(NRAES, 2006a).
Forages and grazing
Fertility, legumes, and
nutrient cycling
Legumes like clover, alfalfa, birdsfoot
trefoil, sainfoin and vetch have the
ability to convert atmospheric nitrogen
to the plant-available form of nitro-
An inventory will allow you to match your resources with your grazing goals. gen through the symbiotic work of
Photo courtesy USDA NRCS. Rhizobium bacteria, which occur
Page 4 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
5. naturally in a healthy soil. A composi-
tion of from 30 to 50 percent legumes in Managing spring-to-fall pasture recovery periods though
pastures combined with nutrient cycling rotational grazing
from high-impact grazing will provide Bill Murphy, a grazing expert in Vermont, relates a story about a success-
all the nitrogen the pasture needs to be ful grazing dairy farm in Vermont in his chapter on Pasture Management
sustainably productive under optimum to Sustain Agriculture in Miguel Altiera’s book Agroecology: The Science of
conditions (Gerrish, 2007). Jim Ger- Sustainable Agriculture. On the farm, 60 lactating Holsteins and 15 dry
rish, former Missouri pasture researcher cows and heifers were fed on six hectares (14.83 acres) of pasture from
and now a grazing consultant, has noted April 29 to about June 15. Total pasture size is 20 hectares (49.42 acres).
that, based on your environment, you In late May, the Hansons harvested and ensiled surplus forage from the
remaining 14 hectares (34.59 acres). In June, six hectares (14.83 acres) of
can run your pasture program entirely
the machine-harvested land was brought into the grazing rotation. In
on nitrogen coming from nitrogen-fixing July, a second crop of forage as hay was harvested from the other eight
legumes. In less favorable environments, hectares (19.77 acres). In September all 20 hectares (49.42 acres) were
added inputs of lime and other soil nutri- included in the rotation. Cows grazed until mid October; heifers and dry
ents may be needed to allow legumes to cows grazed until about November 1 (Murphy, 1995).
thrive (2007). For pastures under high
density grazing systems, from 70 to 85
percent of the nitrogen taken in by the high-quality forage to lactating cattle. Plant
animals is returned and cycled back to recovery periods between grazing events
the soil in the form of feces and urine. should correspond to seasonal changes in
Thus a diverse pasture with a significant plant growth rates (Murphy, 1995). Pas-
legume component, which is managed ture plants grow faster in the spring than
intensively with heavy stocking and fre- in the summer, and cool season plants have
quent moves, has the potential to become a second growth period in the fall. Manag-
a stable, closed system. ing grazing according to plant growth and
recovery is crucial to successful rotational
Grazing systems and plant grazing. Bill Murphy, a Vermont graz-
ing expert and author, cites an example
recovery time of a farm in Vermont that has successfully
If given a choice, livestock will eat the high- negotiated the changes in pasture recovery
est quality, most palatable plants in a pas- rates to feed 75 dairy cattle on just over 49
ture. In order to ensure that plant biodi- acres (Murphy, 1995). See the accompany-
versity is maintained in the pasture, it is ing information box for details on how 49
necessary to set up a grazing management acres of pasture can provide fresh forage
system to better control livestock grazing. during the growing season as well as ensiled
The elements of grazing that should be con- forages for the winter.
trolled are timing and intensity of grazing.
This means controlling animal numbers, For more information, see the ATTRA
how long animals are in a pasture and the publications Rotational Grazing and
length of the recovery period the pasture Pasture, Rangeland and Grazing Man-
is given before grazing again. Rotational agement or review ATTRA’s grass farming
grazing systems take full advantage of the publications at www.attra.org/livestock.
benefits of nutrient cycling as well as the html#Grass.
ecological balance that comes from the
relationships between pastures and graz- Forage management during the
ing animals. High-density stocking for summer slump
short periods followed by adequate recov-
Cool-season perennial grass and legume
ery periods helps to build soil organic mat-
pastures will often begin to decline in late
ter and develops highly productive, dense,
July and August. Most of their growth
resilient pastures.
occurs in the spring and early summer,
In rotational grazing systems, plant when you can have good forage yields and
recovery time is of crucial importance excellent grazing for dairy and beef cattle.
to pasture health and to the provision of But when the summer slump arrives, we
www.attra.ncat.org ATTRA Page 5
6. 4) Add additional land into the grazing
rotation by taking an early cut of hay
from some fields, then allowing them to
regrow before grazing them.
5) Consider warm-season annual crops to
fill in during the summer slump. Mil-
lets, sorghum x sudangrass and several
varieties of brassicas such as turnips are
available and can be spring planted and
grazed during the late summer. Warm-
season annual grasses are generally more
nutritious than warm-season perennials
and can maintain the cattle on a high
plane of nutrition through the summer
until the cool-season grasses recover.
Forage legumes like red clover provide nitrogen fertility to the soil and high protein
for grazing cows. Photo by Mary Rinehart.
need to be able to extend the recovery peri- Extending the grazing season
ods to give these pastures time to regrow. Stockpiling is defined as letting forage grow
We also need to keep our animals on a high during the summer and deferring grazing
plane of nutrition and maintain them with- to the fall or winter. This is an effective way
out expensive feed inputs. to provide winter forage in some areas and
can reduce the need for harvested forage. If
Here is a list of several things you can do to it reduces hay use at all, significant savings
get animals through this downtime in the can be realized. This system works well for
summer when grazing cool-season grasses. early winter when spring-calving cows are
1) Graze cool-season pastures closely in the in mid pregnancy. Stockpiled grazing can
spring, leaving about a 2-inch stubble. be followed with meadow feeding of high-
Be careful to rotate at the right time so quality alfalfa hay prior to calving.
animals do not have the time to graze the Stockpiling has been shown to work well
regrowing shoots before the plant recov- given appropriate pasture management
ers or you will begin to deplete the root and efficient allocation of dormant pasture
reserves. Close grazing in the spring during the winter. Many grass species will
makes cool-season grasses tiller, or send maintain a relatively high nutrient content
out side shoots that grow into new leaves and palatability for several months after
and more forage later on in the season. dormancy begins. In the Intermountain
2) As the temperature increases and West, Altai wildrye has been suggested for
plant growth declines, leave a little stockpiling due to its large stature, abil-
more residue on cool-season grasses if ity to stand up under snow and ability to
you can. Move cattle when the grass is maintain nutrient quality and palatability
from 3 to 4 inches in height. This will well into the winter. Others to consider are
make more leaves available to cap- reed canarygrass, tall fescue and alfalfa.
ture sunlight and supply nutrients the The use of stockpiling as a fall or winter
plant needs to regrow. feeding strategy may not work in all cli-
mates or on all soil types.
3) Slow the speed of your rotation when
growth slows. Grazing removes older Two extra months of grazing can signifi-
leaves and allows newer, more nutri- cantly reduce the costs associated with
ent-dense leaves to take their place. producing and feeding hay. In some cases,
However, grazing plants that are not producers have been able to utilize stock-
fully recovered from the previous piled forage and eliminate the need for
grazing will damage plants. Watch hay feeding. This usually works better in
your residue height. climates where the dormant grass can be
Page 6 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
7. preserved longer under adequate snow Silage can be an excellent source of supple-
cover or because of reduced microbial mental nutrients. Allow pasture to be the
decomposition caused by low temperatures primary feedstuff for the cattle and feed
and limited moisture. the supplement later in the day after the
cattle have grazed for several hours. Pro-
Stockpiled forages can either be limit fed
tein tends to increase forage utilization by
(allowing only so many hours of grazing per
grazing livestock, but feeding too much
day) or fed by strip grazing with a movable
protein can reduce pasture intake and
electric wire or poly tape. Other options
result in inefficient pasture utilization.
for feeding stockpiled forages are to swath
them with a hay mower, and then rake Unwilted, long-cut grass has been success-
them into windrows. Termed swath graz- fully ensiled in piles and covered with white
ing, cattle graze directly off the windrow plastic. According to Allan Nation (2005),
during the winter by using an electric wire editor of Stockman Grassfarmer, the grass
or tape to ration hay on a daily basis. This is cut and blown with equipment such as
is similar to strip grazing in that the wire is an Alpha-Ag Lacerator and blown into a
moved each day to expose a predetermined wagon, then stacked, covered and vacu-
amount of forage for grazing. This method, umed. Silage made this way can produce
while still relying on a tractor to cut and high-quality feed and will not spoil during
windrow the hay, reduces the amount of feeding as long as it is fed out every day.
fuel, materials and hay equipment needed The New England Small Farm Institute
for bale and feed hay by eliminating the and the Connecticut Cooperative Exten-
baling process altogether. Swath grazing sion System has also done some research
works best in dryer regions where weath- with this system and many farmers in New
ering is less likely to reduce the nutritional England have successful used this tech-
quality and palatability of the hay. nology (Markesich, 2002).
Corn and grass-legume silage Types of silage
Corn silage should be fed to ruminants
on pasture when the forage energy con- Type Crude protein Fiber Energy
tent is inadequate, and if it is cost effec- Grass and small
tive to make and feed silage. Otherwise, grain silage
High High Low
corn silage is probably not worth it. Corn
silage is superior to grass silage for cattle Corn silage Low Low High
grazing high-quality pasture. Feeding a
high-protein, low-energy supplement such Legume silage
High High Low
as grass or grass-legume silage to cows on (clovers, alfalfa)
high-quality pasture causes cows to reduce
their grazing intake. However, high-energy
corn silage has the opposite effect. Con- Dairy housing
sider grass silage for winter feeding in Modernization of the following systems
addition to high-quality hay. Grass silage provides the most cost-effective means of
can be cut, baled and wrapped much like reducing energy use on the farm, includ-
hay. This is referred to as haylage, and the ing the dairy barn itself:
ensiling process is completed within the
wrapped bale. • Water heating and space heating
systems
Grass or alfalfa silage requires less energy • Lighting
inputs than corn silage, due to the peren- • Ventilation fan motors
nial nature of these crops. Grass or alfalfa • Milking equipment, including
silage does not require annual tillage, pre-coolers, energy-efficient com-
planting or fertilization. However, the ratio pressors, variable speed pumps
of energy output per unit input is slightly
lower than corn silage.
www.attra.ncat.org ATTRA Page 7
8. • Electrical components, because • Provide at least 80 square feet per
dirty contacts waste energy and cow for Holsteins and similar-sized
pose a fire hazard breeds and 65 square feet for Jer-
• Timers on heating components seys. Some producers provide 100
(Anon) square feet per cow.
After addressing these areas of concern, • Use fi ne, dry wood shavings or
you can begin to determine other areas sawdust for bedding. Alterna-
that need treatment, such as installation tive bedding materials are being
of solar fencing, solar or wind generated investigated.
water pumps and more efficient manure • Aerate the pack twice daily 10
handling techniques. inches deep or deeper to keep it
aerobic and fluffy. Biological activ-
Compost bedding dairy barns ity helps dry the pack.
Compost bedding dairy barns are an inte- • Add bedding when it begins to stick
grated approach that solves many farm to the cows. Have bedding supply
problems, including the problem of manure available so you don’t end up add-
handling. This design also utilizes the heat ing fresh bedding too late.
of aerobic fermentation to heat the barn • Enhance biological activity to gen-
space. Compost is spread on fields season- erate heat to drive off moisture and
ally, and nutrient loss is much less than ventilate the barn well to remove
with spreading raw manure. However, the the moisture.
compost bedding process requires aera- • Use excellent cow preparation at
tion twice a day and ventilation to remove milking time (2008).
moisture. Maintaining a compost bedding
space requires constant attention and suffi- Whether a compost bedding barn or a
cient equipment to aerate the bedding pack conventional barn with timely manure
twice daily. Aeration can be accomplished removal is more efficient depends on sev-
with a modified compost turner, a front eral elements, such as frequency of manure
end loader, or a bobcat. Compost bedding removal, available land for disposal, pas-
barns reduce the need to purchase and ture nutrient load (namely phosphorus)
ship bedding materials such as wood shav- and personal preference. In addition to
ings, which represents not only a cost sav- considering the energy and monetary cost
ings but an energy savings as well. Marcia of inputs such as bedding and time, con-
Endres and Kavin Janni of the University sider the amount of tractor time needed to
of Minnesota suggest the following prac- remove manure versus aerating compost
tices to ensure a successfully composted bedding twice daily.
bedding pack: To assist you in determining energy effi-
cient practices, you can access the online
NRCS Energy Estimator for Animal
Housing at http://ahat.sc.egov.usda.
gov. This interactive tool will allow you
to input your farm data and energy costs.
The tool will then recommend practices
to conserve energy and estimate savings
based on your location.
Fencing and water systems
Fencing for grass-based dairies can be a
significant cost and should be designed
for ease of use and flexibility of paddock
Dairy cattle graze paddocks divided with a single strand of electric poly wire. size, as paddock size will likely change
Photo by Linda Coffey. as the growing season progresses.
Page 8 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
9. More and more grass-based dairy produc-
ers are utilizing electric fencing for perma-
nent perimeter fencing and for inner pad-
dock sections. The permanent perimeter
fence is usually constructed with wooden
or steel posts and high-tensile wire. The
perimeter fence carries a current that is
distributed to the fences that subdivide the
individual paddocks. The paddocks can
be divided with either permanent fencing
or with temporary posts and poly wire or
tape. The advantage of temporary paddock
fencing is that the paddock sizes can be
changed according to animal numbers or
forage production throughout the season.
Some of the necessary equipment for
designing and constructing electric fences Electric poly wire is a cost-effective tool for maximizing pasture utilization.
include: Photo courtesy USDA NRCS.
• A charger (energizer) and ground-
• Tools, including volt meters, crimp-
ing rods
ing devices, lightning arrestors and
• High-tensile wire, 10, 12.5, or surge protectors
14 gauge
• Posts, such as wood and steel (for
• Tensioners and insulators permanent and corner braces) and
• Poly tape and poly wire for section- step in (temporary)
ing off paddocks
There are many manufacturers and dis-
tributors of electric fencing equipment.
Your local feed store or farm co-op might
be the first place to look. Online dealers
such as Gallagher are also a good place
to obtain materials. Visit the Web site at
www.gallagherusa.com.
Water is the most important nutrient
for dairy cattle (NRC, 2001). An ade-
quate water supply is necessary to renew
the cows’ body water content that is lost
daily through milk production, urine and
feces, sweating and exhalation. A 1,500-
pound lactating cow producing 60 pounds
of milk per day requires 21.8 gallons in
cool weather, about 40 degrees Fahren-
heit, and 28.9 gallons in hot weather, about
80 degrees (Waldner and Looper). Water
should be clean and fresh, as dirty water
decreases water intake. Nutrient metabo-
A simple electric fence provides protected access to lism in the body depends on water, and if
a stream for livestock watering. PVC pipe is used as a
flotation device for the bottom strand. Photo courtesy a cow stops drinking, nutrient metabolism
Alice Beetz. (growth and lactation) will decrease.
www.attra.ncat.org ATTRA Page 9
10. pumping, including further resources,
can be found in the ATTRA publication
Solar-Powered Livestock Watering Systems
online at www.attra.org/attra-pub/PDF/
solarlswater.pdf or by calling ATTRA at
1-800-346-9140. Ram pumps utilize stream
flow to pump water and can lift water from
a stream to a tank without electricity.
Clemson University has plans and specifi-
cations for building a ram pump at www.
clemson.edu/irrig/equip/ram.htm.
The USDA booklets Electric Fencing for
Serious Graziers and Watering Systems
for Serious Graziers from Missouri Natu-
ral Resources Conservation Service contain
A single source provides water to multiple paddocks. Photo courtesy USDA NRCS.
detailed suggestions, plans and trouble-
shooting ideas and should prove valuable to
producers designing and constructing fenc-
Water should be delivered to cattle in the ing and watering systems. See the Further
most efficient manner possible. Tanks can resources section below for information on
be placed in each paddock, or can be made how to order these guides.
portable and moved to individual paddocks
as the cattle move. Water can come from Seasonal dairying and
municipal sources, wells, springs, ponds or
streams. Solar pumping systems are effec- considerations on
tive for delivery from wells or ponds, and reproduction
low-input technologies such as ram pumps Dairying in the United States has tradi-
can supply minimum water flow to tanks tionally produced milk on a year-round
from running streams and can even pump basis with a feeding system of silage, hay
water uphill if sufficient head is achieved. and grain. However, seasonal dairying is
Detailed information on solar water becoming more popular. It was first prac-
ticed in New Zealand, where little grain
is grown and government subsidies disap-
peared years ago. Seasonal systems match
the reproductive cycle of the cows to avail-
ability of forage. The periods of highest
nutrient requirements of the cow — during
calving and lactation — are timed to occur
in the season of highest grazing quality and
quantity. This usually is in the spring.
In seasonal dairying, since all the cows dry
off at once, it is not necessary to milk for a
couple of months during the year. The idea
is to avoid the period when milk production
is most expensive. In very hot, humid cli-
mates, summer might be the time to dry off
the cows. Many dairy producers appreci-
ate this rare opportunity for time off from
Homemade hydraulic ram pump. Ram pumps are milking, but all must adjust to a period of
simple and inexpensive to build. All the materials can
be purchased at your local hardware store. Photo cour-
no income from milk. As more dairies have
tesy Clemson University Cooperative Extension Service. become seasonal, milk processors have
www.clemson.edu/irrig/Equip/ram.htm begun indicating that producers may be
Page 10 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
11. penalized, especially in certain parts of the breeding is accomplished during the
country where there is already an oversup- cooler months. In addition, seasonal
ply of milk in the spring of the year. calving allows the farmer to concen-
trate on the actual process of calving
Managing for a short-season calving period
for an intense period of time, and to be
is critical for the seasonal dairy farmer.
available for help if needed.
The goal is for all cows to calve within a
six- to eight-week period. This can be done
without hormonal injections and achieve The estrous cycle
a fairly high degree of success. Success The reproductive cycle for cattle is known
depends on body condition, adequate as the estrous cycle, after estrus, or heat.
nutrition and good all-around reproduc- Cows cycle every 21 days beginning with
tive management. Getting cows bred in a the onset of puberty, which begins when
short time period may be the biggest chal- cows are about eight months old. Manag-
lenge in a seasonal dairy program. Pro- ing the estrous cycle is a challenging task,
ducers are finding that getting cows off especially for organic dairy farmers. Syn-
concrete and into pasture aids in detecting thetic hormones commonly used in conven-
estrus in cows. Unfortunately, producers tional dairies are not allowed in organic
are also learning that vegetative forages are production. This section will describe the
very high in rumen degradable protein and characteristics of estrus and some consid-
low in energy. Poor body condition and low erations for managing reproduction for
energy intake have a negative impact on organic and seasonal dairying.
reproduction; therefore some grain feeding
should be done to counter the tendency for
cows to lose condition because of decreased
Characteristics of estrus and breeding in cattle
available energy.
Estrus – the period of time when a cow shows behavioral signs of heat
Keys to success for transitioning to seasonal Estrous – of, relating to or characteristic of estrus; being in heat
production include:
Age at puberty:
• Synchronizing estrus From 12 to 18 months, usually first bred at 15 months depending
• Detecting heat on breed and size
• Breeding cows within a narrow Cycle type:
window of time; approximately Polyestrous, or all year
six weeks Cycle length:
21 days, with a range of from 18 to 24 days
• Maintaining cows on a high plane
of nutrition Duration of estrus (heat):
18 hours with a range of from 10 to 24
• Providing adequate facilities for
calving, calf raising and breeding Length of lactation:
Approximately 280 days (Merck, 2006)
in one season
Best time to breed:
• Culling late breeders, or letting
At the first sign of heat. As the egg ages conception rates may
them go through a complete breed- decrease. The younger the egg, the better the conception rate
ing season and trying to get them (Karreman, 2007)
bred next season
First estrus after parturition:
Varies, best to breed at 60-90 days post partum (Merck, 2006)
Benefits of seasonal calving
Ovulation:
With spring calving, a producer has Occurs from 10 to12 hours after the end of estrus.
the ability to match peak lactation with Uterine bleeding occurs about 24 hours after ovulation in most
forage production. The cows are also cows, but may require vaginal examination for detection. Bleed-off
dry when forage is scarce in the win- usually indicates heat occurred from 2 to 3 days prior (Karreman,
ter months. For fall calving, the cows personal communication)
are dry during the hot summer months. Length of Gestation:
Milk prices are generally higher, and 283 days
www.attra.ncat.org ATTRA Page 11
12. Figure 1. The estrous cycle
Day 21 is estrus. Standing heat occurs.
Ovulation occurs from 25 to 32 hours
after onset of estrus.
Signs of heat
The primary sign that indicates a cow is
in heat is a cow standing to be mounted,
termed standing heat. Some secondary
signs that occur before, during or after
standing heat and are not necessarily
related to ovulation include:
• Mounting other cows
• Discharging mucus
• Swelling and reddening of vulva
• Bellowing, restlessness and trailing
• Rubbed tailhead or dirty flanks
• Chin resting or back rubbing
• Sniffing genitalia
• Not letting milk down as usual
These secondary heat signs indicate that
breeding time is getting close. Another
sign to look for is metestrus bleeding,
which is a bloody mucus discharge that
occurs one to three days after estrus
and is caused by high estrogen levels. Met-
FSH: follicle-stimulating hormone, responsible for development of follicles estrus bleeding is variable from cow to cow.
Follicle: releases ovum (egg)
LH: luteinizing hormone, stimulates ovulation and forms corpus luteum
It signals that an animal was in heat, and is
CL: corpus luteum, mature follicle after ovulation, produces progesterone either bred or open. If the cow is open she
Progesterone: hormone that maintains pregnancy will be in estrus in another 18 or 19 days.
Graph courtesy of University of Missouri Extension.
Detecting estrus
The cow’s estrous cycle lasts for 21 days. Most mounting activity occurs in the
The cycle is split into four periods: evening and early morning. It is impor-
metestrus, diestrus, proestrus and estrus. tant to time observations accordingly.
Days one through three are in metestrus. Provide ample room for cattle to behave
This occurs immediately following ovula- naturally and minimize muddy, slippery
tion and is indicated by a rise in progester- conditions. Employees should be trained
one, which maintains pregnancy. in heat detection and assigned to duties
accordingly, observing cows for 30 min-
Days three through 19 are diestrus, wich utes in the morning, again in mid to late
is marked by high progesterone and afternoon and again at midnight. At
low estrogen in system. If pregnant, the the very least, observe cows in the early
animal will remain in this phase through- morning and early evening. Maintain
out her pregnancy. records of activity, record all heats and
Days 19 and 20 are in proestrus. This is develop a heat expectancy chart for each
marked by a decrease in progesterone and cow. Consider using heat detection aids,
a rise in estrogen if the cow is not pregnant, such as those listed in the box on the top
and signs of heat begin. of the next page:
Page 12 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
13. Conception rates
Heat detection aids
A 60-percent conception rate for the first
• Use heat detection records and expectancy
charts to estimate heat periods.
service is average for most dairy herds,
and about 2 percent of the cows in an
• Perform cow-side milk progesterone assays average herd need more than five services
for problem cows. to conceive. A high number of repeat
• Use tailhead markings such as paint or Kamar breeders can indicate a problem. Con-
pressure-sensitive devices. These are effec- sider culling for severe repeat breeders.
tive but conception rates are usually lower if
not accompanied with direct visual obser-
vation of standing heat. Tailhead markings Synthetic hormones and
can give false positives due to any number organic production
of situations that would result in markings
Synthetic hormones are not allowed in
being smudged or rubbed off.
organic production. Therefore, the rou-
• Consider heat detector animals. Gomer bulls tine manipulation of reproduction such
are surgically altered but still mount to breed. as heat synchronization with hormones
Cows will also mount cows in estrus.
and the administration of gonadotropin-
• Understand that cows are generally more releasing hormone (GnRH) to improve
active during estrus. conceptions rates are not allowed in
organic dairy farming. Organic dairy
farmers rely on cultural practices such
Timing of breeding or as heat detection, photoperiod manipula-
insemination tion, culling and homeopathic or botani-
cal aids to synchronize estrus.
Cattle sperm is viable in the cow’s vagina
and uterus for from 18 to 24 hours. Ovu-
lated eggs remain viable for from 10 to 20 Natural and homeopathic aids
hours. The older the egg is when fertilized, for estrus synchronization
the greater are the chances for embryonic Dr. Hubert Karreman, a Pennsylvania
death. For optimum fertilization, insemi- veterinarian who has seen and treated
nate cows as soon as possible because dur- his fair share of organic dairy cattle
ing estrous observation you may have only on farms throughout the mid-Atlan-
seen the cow’s very last standing mount. tic region, suggests that observation of
even the slightest change in behavior
Photoperiod extension is critical to successful heat detection.
According to a 1994 study in Ohio, it is He has noted that good dairy farmers
thought that spring breeding is favored can “just see” that a cow is in estrus by
by photoperiod extension, which improves the way she looks and behaves, includ-
endocrine gland activity related to ovula- ing such characteristics as milk letdown
tion (Zartman, 1994). Photoperiod exten- and feed intake (Karreman, 2007).
sion is nothing more than extending day His book Treating Dairy Cows Natu-
length with artificial light. Some produc- rally, which includes a section about
ers may be able to take advantage of pho- reproduction and heat cycles, provides
toperiod extension for seasonal dairying, first-hand knowledge from an expe-
especially in mild regions where cattle are rienced veterinary practitioner. The
less likely to experience breeding problems section describes basic anatomy and
associated with hot climates. Photoperiods physiology; nutritional effects on fertil-
can also be manipulated to increase lacta- ity; heat detection methods and sugges-
tion efficiency. For detailed information on tions; reproductive disorders; and botan-
photoperiod manipulation, see the articles ical and homeopathic treatments. See the
by Geoffrey Dahl referenced below in the Further resources section for informa-
Further resources section. tion on obtaining a copy of the book.
www.attra.ncat.org ATTRA Page 13
14. Dry cow management hormonal change and imbalance.
Do not carry out any treatments,
Develop a working relationship with a large
vaccinations or other procedures
animal veterinarian who is qualified and
during this time. Leave her udder
comfortable working with grass-based sys-
alone during this time as well.
tems. If you are considering organic pro-
Plenty of free choice mineral and
duction, you might also consider a quali-
vitamin supplementation begin-
fied holistic veterinary practitioner. The
ning three months before dry off
main point is that any health program,
will help the immune system cope
including a dry cow program, should be
with these natural changes.
developed with the input of a veterinarian
who understands and respects the systems • Animal handling should be exer-
approach to production that is exemplified cised with extreme care. Yell-
by grass-based dairies. ing, pulling, hitting and banging
of gates causes stress and lowers
A dry cow program is a year-long natural immunity. Sunshine and
systematic plan that involves preven- pasture are important for animal
tative health, nutrition, observation, well-being and maintenance of
I
f you are proper milking procedure, a commit- natural immunity.
ment to animal welfare and treatment • Observe somatic cell counts prior
considering when conditions warrant. The follow- to dry-off period. Think of treating
organic ing points should be kept in mind when only those cows with high counts.
production, developing a dry cow program: Probiotics and whey products have
you might also • The cow should be in good been successful treatments. Causes
consider a qualified condition at dry off. Dry-off time of a high somatic cell count include
is too late for rebuilding nutri- acidosis, lack of barn and equip-
holistic veterinary
tional reserves. ment sanitation, poor milking
practitioner.
• The cow requires minerals, procedure and negligent cow
vitamins, amino acids and handling, which can cause stress.
enzymes to rebuild her body • Observe the cow after calving. Calv-
stores and get ready for the next ing difficulty and health problems
production cycle. associated with calving are indica-
• Dry cow management begins three tors of low immunity at calving.
months before calving, which is
usually a month before dry off.
Sample dry cow management system
• Salt, kelp, calcium and phospho-
• Feed an adequate amount of dry hay for
rus must be made available with rumen function.
free choice.
• Provide calcium, phosphorus and trace
• Feed bulk dry cow rations such minerals including salt available free choice
as grass, hay and no more than 5- at all times.
or-so pounds of grain. Too much • Provide vitamin A and E and selenium sup-
energy will fatten her and can plementation if needed, especially in the
cause parturition difficulty. Corn winter when green forage isn’t available.
silage is also a very good dry cow • Natural treatments help boost immune system
feed; just be sure not to feed too and include kelp with or in addition to aloe
much. Feed 20 pounds or less per vera pellets at two weeks prior to calving.
day for cows on grass. • Use whey products and probiotics for high
• Prepare the cow for a natural somatic cell count cows at one week after
dry up.
immune system drop after dry off.
This generally occurs about seven • Consider pre-milking for cows with past
udder trouble. Pre-milking is stimulating
days after dry off, and again two
the udder by hand massaging to encour-
to three weeks before and after age milk let-down.
calving. These are stressful times of
Page 14 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
15. Grazing nutrition
Ruminants are adapted to use forage
because of a symbiotic relationship with
rumen microbes. Therefore, feeding the
rumen microbes will in turn feed the
animal and maintain ruminant health
and productivity. Some basic principles
of grazing nutrition include:
• Ruminant nutritional needs
change depending on age, stage
of production and weather.
• Adequate quantities of green
forage can supply most —if not
all — the energy and protein a
ruminant needs.
• Forage nutritional composition
High-quality legume pasture. Photo courtesy USDA NRCS.
changes depending on plant matu-
rity, species, season, moisture and
grazing system. Supplementing dairy cows
• Supplementation may be necessary The energy requirements of lactating
when grass is short, too mature, cattle can be met with fresh pasture or
dormant or when high-producing with high-quality grass-legume hay or
animals require it. silage in the winter. However, energy
supplementation on pasture is often
• Excessive supplementation may
effective in maintaining high gains and
reduce the ability of the rumen
higher milk production. Dry cows can
microbes to use forage.
subsist on lower-quality feedstuffs but
• Supplementation with a high- will need to be maintained at an accept-
protein forage or grain when the able body condition score to successfully
herd is grazing grass-legume breed and deliver a healthy calf.
pastures may cause animals to
Energy is important for cattle on high-
refuse more pasture and produce
protein pasture because the microbes
less milk. If protein overfeeding
that occupy the rumen need energy to
continues for too long, cows may
digest all the protein the animal ingests.
lose condition, not breed back and
If the microbes do not get enough energy,
develop hoof problems.
the protein is converted to urea and is
Grazing cattle require green, growing, passed through in the urine, resulting
leafy grass and legumes to meet the pro- in inefficient protein use. For very high-
tein and energy requirements needed producing dairy cattle, an energy sup-
to maintain lactation. As the cow pro- plement such as grain or corn silage can
gresses through her lactation period, the result in better protein digestion, and
amount of forage required will increase. therefore higher milk production and
Maintaining a high plane of nutrition is greater weight gains for growing cattle.
critical for good grazing management, as Most dairy graziers who supplement their
covered in the Forage and Grazing sec- cattle provide from 8 to 18 pounds of corn
tion above. Appropriate supplementation or another high-energy grain per head
is necessary when forage is inadequate, per day, depending on the quality of the
which is the subject of the next section. pasture, in addition to forage or pasture.
www.attra.ncat.org ATTRA Page 15
16. pasture exposure and provid-
When to supplement ing high-quality forage in the
Supplementing energy is helpful on dormant season.
vegetative, well-managed pastures for Recordkeeping is a critical component
more efficient utilization of forage protein for of a livestock health plan, and is of vital
high-producing animals. importance to a dairy farmer. ATTRA has
Supplementing with protein is necessary on a set of organic livestock recordkeeping
low-quality pasture and rangeland or when forms that help the producer document
continuously grazing temperate warm- pasture use, livestock inventory, indi-
season pastures. vidual cow health and breeding records.
To access these forms, visit http://attra.
ncat.org/organic.html#livestock or call
Digestible fiber feeds are good energy
1-800-346-9140.
sources for dairy cattle on high-quality
forage because digestible fiber feeds do not To learn more about animal health
reduce intake and provide energy for pro- and disease prevention, see the ATTRA
tein metabolism. Examples of digestible publication Cattle Production: Consid-
fiber feeds include corn gluten feed, made erations for Pasture-Based Beef and
with corn gluten meal and bran; wheat Dairy Producers.
midds, made from screenings from wheat
flour processing; and whole cottonseed. Organic dairy production
For more in-depth information on cattle There is an increasing demand for
nutrition refer to the ATTRA publication organic and pasture-based dairy prod-
Ruminant Nutrition for Graziers. ucts. Many conventional dairy farms
are transitioning to pasture-based pro-
Health management duction and also becoming certified
organic. This section will discuss how
The natural living conditions of pastures
to get started in transitioning a dairy to
decrease animal stress and remove unneces-
certified organic production.
sary burdens on the immune system. Other
practices such as sanitation, quarantine of Several challenges are typical in the transi-
new animals and the use of probiotics in tion period of changing from conventional
young animals can also foster a healthier to organic production. The primary con-
environment for livestock. Disease preven- cern is to develop an ecological approach
tion is the best health plan you can develop to production as opposed to an input
for your cow herd, and a well-planned pas- approach. In practical terms, this means
ture-based system will effectively eliminate developing soil fertility through grazing
many vectors for disease and alleviate many management; careful use of winter manure;
nutritional disorders. controlling pests and disease through san-
Cattle health management is a disease itation, plant and animal diversity; and
prevention strategy that includes: stress reduction. These are just a few con-
cerns during the transition period.
• Fostering natural immunity in
animals by increasing animal and In transitioning to organic production,
plant biodiversity on the farm you will be confronted with new and often
• Balancing nutrition through rigorous recordkeeping and management
pasture grazing management and requirements. Yearly inspections will be
mineral supplementation required to verify compliance to the organic
• Development of a proactive dry regulations. In addition, there can be a sub-
cow management program stantial cost to the certification process.
• Proper milking procedures The first step in transitioning to organic
• Reducing animal stress through production is to select a certifier in your
appropriate facility design and area. Many states have one or more
Page 16 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying
17. • Health care – The producer
USDA accredited certifying agents must establish and maintain pre-
The USDA maintains a list of accredited ventative health care practices,
certifiers, listed by state, on the National including selection of appropriate
Organic Program Web site at www.ams. livestock species, adequate nutri-
usda.gov/nop. If you would like a printed
list of the certifiers in your area, contact
tion, appropriate housing and
ATTRA at 1-800-346-9140. sanitation, freedom of movement
and reduction of stress, admin-
istration of vaccines and proper
certifying agencies that are authorized treatment of sick animals even if
agents by the National Organic Program. organic status could be affected.
Once you select a certifier, you will com- • Livestock living conditions – The
plete an application packet, which will producer must establish and
become your organic system plan. Remem- maintain living conditions that
ber that it takes three years from the date accommodate health and natu-
of the last application or use of a restricted ral animal behavior, including
substance such as synthetic herbicides and pasture for ruminants.
I
fertilizers until a product can be sold as • Recordkeeping – The producer t takes three
organic. It also takes one year to transition must maintain records concern- years from the
a herd to organic. Alternatively, an organic ing production, harvesting and date of the last
herd can be purchased once the farm is handling of agricultural products. application or use
certified organic. The records must fully disclose all
of a restricted
activities and transactions, be read-
The organic system plan (OSP) ily understood and audited and be substance such as
According to the National Organic Pro- maintained for five years. synthetic herbicides
gram Regulations, every certified organic Detailed information on these crite- and fertilizers until a
farm, ranch and handling operation must ria can be obtained from the National product can be sold
submit an organic system plan when apply- Organic Program’s Web site at www. as organic.
ing for certification. The OSP must be ams.usda.gov/nop or by contacting
updated annually or more frequently if ATTRA at 1-800-346-9140.
operational changes are made. The Northeast Organic Dairy Produc-
An OSP includes the name and contact ers Alliance (NODPA) has many useful
information of the producer, the type of documents on their Web site for farmers
operation seeking certification and a live- thinking about transitioning. Access the
stock inventory. In addition, the following information at www.nodpa.com.
elements should be documented to main-
tain an audit trail in order to establish Proposed organic dairy
organic system integrity:
grazing standards
• Livestock origin – Livestock prod-
As of this writing, the National Organic
ucts that are to be sold, labeled
Program is considering a new section
or represented as organic must
of the rule that covers grazing and
be from livestock under continu-
ous organic management, except housing of organic livestock. The fi nal
as is provided for in the National rule should be published in 2009.
Organic Program regulations. The National Organic Program regulations
• Feed – The total feed ration currently include grazing as a portion of
must be composed of agricul- the total feed requirements of ruminant
tural products, including pasture livestock. According to NOP § 205.237,
and forage, that are organically the producer of an organic livestock opera-
produced and, if applicable, tion must provide livestock with a total feed
organically processed. ration composed of agricultural products,
www.attra.ncat.org ATTRA Page 17
18. including pasture and forage. In addition, Animal welfare
livestock living conditions are addressed Animal agriculture has become signifi-
to accommodate the health and natural cantly focused on production efficiency, as
behavior of livestock. A proposed change to evidenced by confinement systems, total
the rule states that producers shall ensure mixed ration delivery of concentrated feed-
that, during a pasture growing season of stuffs, genetic selection for high-producing
at least 121 days, at least 30 percent of the cows and the use of hormones and antibiot-
cow’s dry matter intake shall come from ics to sustain high production levels. These
green, growing pasture. practices have increased the production
of milk and milk products dramatically,
The proposed organic pasture rule states
but often at the expense of animal welfare.
that all ruminants should be managed on From an economic perspective, grass-based
pasture year-round by providing graz- and organic dairies place more attention
ing throughout the growing season and on income than on high productivity. It
access to the outdoors throughout the has been mentioned that some dairy farm-
year, including during the nongrowing ers with less extensive production systems
season. Dry lots and feedlots will no lon- achieve a higher income by lowering their
ger be permitted in organic production production costs. From an ecological per-
under this proposed rule. Instead, the spective, grass-based and organic dairy
pasture system must include a sacrificial farms measure success in increased animal
pasture for grazing and to protect the other health and a more appropriate quality of
pastures from excessive damage during life for the farm family.
periods when saturated soil conditions
render the pastures too wet for animals to The grass-fed claim for ruminant
graze (USDA AMS, 2000). animals and products
This publication will be amended in the The USDA Agricultural Marketing Service’s Stan-
future to reflect changes to the rule by dards for Livestock and Meat Marketing Claims,
Grass (Forage) Fed claim gives authority to label
the National Organic Program. For more
grass-fed livestock products according to the
information on the proposed rule, see the following language: Grass and forage shall be
USDA National Organic Program Web site the feed source consumed for the lifetime of
at www.ams.usda.gov/nop. the ruminant animal, with the exception of milk
consumed prior to weaning. The diet shall be
derived solely from forage consisting of grass
Grass-fed standards and (annual and perennial), forbs (e.g., legumes,
process verification Brassica), browse, or cereal grain crops in the
vegetative (pre-grain) state. Animals cannot be
The USDA initiated a voluntary grass-fed
fed grain or grain byproducts and must have
claim standard in 2007 that allows produc- continuous access to pasture during the grow-
ers to use the Process Verified term and ing season. Hay, haylage, baleage, silage, crop
shield in their marketing and label their residue without grain, and other roughage
products as grass-fed. The producer will sources may also be included as acceptable feed
document all verification points, or those sources. Routine mineral and vitamin supple-
mentation may also be included in the feeding
substantive and verifiable production
regimen. If incidental supplementation occurs
claims that add value to the product, and due to inadvertent exposure to non-forage feed-
have them verified by a third party. Two stuffs or to ensure the animal’s well being at all
organizations approved for third-party times during adverse environmental or physical
verification from the USDA are AgIn- conditions, the producer must fully document
foLink, www.aginfolink.com, and IMI (e.g., receipts, ingredients, and tear tags) supple-
Global, www.imiglobal.com/index.aspx. mentation that occurs including the amount,
the frequency, and the supplements provided
See the Further resources section below (USDA AMS, 2007).
for detailed contact information.
Page 18 ATTRA Dairy Production on Pasture: An Introduction to Grass-Based and Seasonal Dairying