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Limiting
Forage Intake for Dairy During Drought
DS-14-97, June 1997, Reviewed May 2004
J. W. Schroeder, Extension Dairy Specialist
When
forage is in short supply and purchased forage expensive and unavailable,
dairy producers may need to reduce forage intake to recommended
minimum levels. Heavier feeding of concentrates or forage substitutes
may be used to maintain nutrient intake. It is advisable, however,
not to limit normal forage intake for dry cows or springing heifers.
Recommended
minimum intakes are found in Table 1. Only normal forage (hay, silage,
pasture or green-chop) of sufficient particle size should be used
to meet minimum hay-equivalent needs. These are expressed on a pound
per hundredweight of bodyweight daily basis and refer to pounds
of air-dried forage with a 90 percent dry matter content or its
equivalent. The suggested minimum forage intakes in Table 1 are
given on both a hay-equivalent and percent of total ration dry matter
basis for use in conventional or total mixed rations, respectively.
Generally, the lower minimum forage intakes given should be used
for only a limited period of three to four months, otherwise more
problems with health, reproduction and milk composition or quality
may be encountered. However, this lower minimum may be used for
longer periods if fiber levels and, preferably, particle sizes are
maintained by use of roughages, forage substitutes or concentrates
with a relatively high fiber content. Even then, some depression
in milkfat test and some increase in health problems may occur.
The
majority of particles for a given forage should be 3/8 - 3/4 inch
or longer. Alfalfa meal or pellets should not be considered in meeting
minimum hay-equivalent needs, while alfalfa cubes or hay may qualify.
Table
1. Recommended minimum forage intakes for dairy cattle*.
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Hay-Equivalent
Intake**
Total
Ration+
Lb/Cwt
Dry
Matter
Bodyweight
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(%)
Producing cows
Extended period 2.0
60
90-120 days 1.5++
45**
Dry cows, springing heifers 1.8
80
Calves under six months
0.8 25
Heifers
1.5
60
Bulls
Under 1000 lb 1.5
50
1000-1800 lb
1.3
50
Over 1800 lb 1.0
65
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*Refers to hay, haylage, silage, pasture or green-chop of normal
particle size.
**For use in feeding conventionally.
+For use in feeding total mixed rations.
++This level may be used for longer periods if acid detergent fiber
levels in the total ration dry matter is kept at 20% or higher,
preferably with ingredients of reasonably coarse particle size.
Purchasing Forage
Purchased hay often can be an economical source of nutrients. This
is especially true when adverse weather is not widespread and concentrate
prices are relatively high. Haylage or silage can sometimes be purchased
at farm sales or from farmers with surplus forage. Ensiled materials
can be transferred to other silos with little risk, provided that
they are well-preserved with a pH of 3.5-4.5.
Carryover
hay or silage from previous years can usually be purchased at lower
prices than material from the current harvest season. Generally,
old-crop forages will equal new crop material in overall nutrient
content. However, they contain less carotene or vitamin A activity
and vitamin E. This should be offset by higher supplementation of
these vitamins.
When
hay or forage prices are not economical, purchases can be limited
to those necessary to meet recommended minimum intakes. If purchased
forage is a more economical source of nutrients than concentrates
or forage substitutes, then buy enough to maintain usual hay-equivalent
intakes.
Several
aspects of quality should be considered when purchasing forage.
If economically feasible, purchased forage should be of such quality
that the total forage dry matter fed to dairy cows will contain
a minimum of 60 percent TDN on a dry matter basis. If home-grown
forage consists mainly of good corn silage, then quality of purchased
hay may not be as critical. When home-grown material is of low nutrient
content, low in palatability or musty and moldy, then purchased
forage should be of relatively high quality.
Grass
hays often sell for appreciably less than legumes. These sometimes
are better buys if they are needed to supplement home-grown hays
or haylages containing high-protein legume forage.
When
no high quality alfalfa hay or haylage is available on the farm,
consider purchasing enough good alfalfa to feed 3-5 lbs per head
daily. Feeding even these limited amounts of alfalfa may help improve
feed utilization and performance. Alfalfa should contain at least
19-20 percent crude protein on a dry matter basis to be considered
for this use.
DS-14-97,
June 1997
NDSU
Extension Service, North Dakota State University of Agriculture
and Applied Science, and U.S. Department of Agriculture cooperating.
Sharon D. Anderson, Director, Fargo, North Dakota. Distributed in
furtherance of the Acts of Congress of May 8 and June 30, 1914.
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