Group Title: Circular Florida Cooperative Extension Service
Title: Feeds, feeding, and nutrient requirements of dairy cattle
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Title: Feeds, feeding, and nutrient requirements of dairy cattle
Series Title: Circular Florida Cooperative Extension Service
Physical Description: 16 p. : ill. ; 28 cm.
Language: English
Creator: Harris, Barney
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville
Publication Date: 1990?
 Subjects
Subject: Dairy cattle -- Feeding and feeds   ( lcsh )
Dairy cattle -- Nutrition   ( lcsh )
Animal nutrition -- Requirements   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
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Statement of Responsibility: Barney Harris, Jr.
General Note: Caption title.
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Bibliographic ID: UF00014474
Volume ID: VID00001
Source Institution: University of Florida
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oclc - 23884108
alephbibnum - 001624897

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Circular 594


-- I


Introduction
Proper feeding and good balanced rations remains the
cornerstone of a successful dairy operation. Milk yield
per cow and the cost of feed to produce milk have by far
the greatest influence on profitability in a dairy operation.
If a dairy is to be successful, the dairyman must
continually strive to adopt practices that allow him to
achieve the greatest output of milk at the most economical
cost. Successful dairying in the future will depend on high
levels of milk production, culling for low production,
controlling feed costs, and the use of good replacements.

Cow identification and good records make good feeding
practices possible. Without milk production records, it is
difficult to feed according to milk production or to use any
well-designed group feeding system.

Milk yields per cow continue to increase annually as
reported by the USDA National Agricultural Statistics
Service. Average production per cow in the U.S. reported
in 1975 was 10,360 lbs as compared to 14,244 lbs in 1989.
Much of this increase in milk production is due to better
nutrition and feeding, overall management practices, and
the genetic improvement of the cow population.

Feeding Standards

Feeding standards have been used since the late 1800s
to help guide nutritionists and livestock producers in for-
mulating rations and feeding livestock. Periodically, the


standards are updated to encompass the most current re-
search information available. Such are the standards that
are now available titled, "Nutrient Requirements of Dai-
ry Cattle," that were updated in 1988 by a subcommittee
on Dairy Cattle Nutrition of the National Research
Council.
Tables 1, 2, and 3 show the nutrient requirements of
dairy cattle as developed by the National Research
Council (1988).
Energy the energy requirements used from this
publication are expressed as net energy for maintenance
(NEM), net energy for lactation (NEL), and total
digestible nutrients (TDN). Even though both TDN and
NEL are acceptable measures of energy, NEL is expressed
as megacalories (Mcal) whereas TDN is given in pounds.

Table 1. Daily nutrient requirements for maintenance of
mature lactating cows.*
Body Crude Vitamins -
Wt. Protein NEL TDN Ca Phos A D
(Ib) (Ib) (Mcal) (Ib) (Ib) (Ib) -(1000 IU)-
1000 .98 7.86 7.58 .041 .029 34 14
1200 1.18 9.02 8.70 .049 .034 41 16
1400 1.37 10.12 9.76 .057 .040 48 19
*Add 20% for growth of lactating cows during first lactation.
The NEL is defined as the energy contained in the milk
produced. Since milk fat is high in energy, cows producing
a higher fat testing milk require more energy per pound
of milk (Table 2).


Barney Harris, Jr. is a Professor and Extension Dairy Specialist with the Dairy Science Department at the Institute of Food and
Agricultural Sciences, University of Florida, Gainesville, FL


FEEDS, FEEDING, AND
NUTRIENT REQUIREMENTS OF

DAIRY CATTLE

Barney Harris, Jr.'










Protein As milk production increases, it becomes im-
portant that some dietary protein escape degradation in
rumen fermentation. Protein that bypasses the rumen is
degraded to amino acids and absorbed from the small
intestine for utilization. These essential amino acids are
needed by the high producing cow and must come either
from dietary protein that escapes degradation or microbial
protein produced during rumen fermentation and passed
along to the small intestine.

The 1988 Nutrient Requirements of Dairy Cattle
discussed for the first time both absorbed and crude
protein. The dietary intake protein is described as unde-
gradable intake protein (UIP) and degradable intake
protein (DIP). Although a specific percent UIP is not
stated, the calculations suggest 35-40% bypass protein.

Processing or heat treatment of feedstuffs increases the
amount of bypass protein in the feedstuff. Commonly used
bypass protein supplements are distillers grains, brewers
grains, corn gluten meal, blood meal, meat and bone
meal, feather meal, and heat treated soybeans (Table 5).

For faster usage and convenience, Table 3 has been de-
veloped to contain the combined requirements for main-
tenance and milk production for different sized dairy cows


producing milk containing 3.5% fat. The compiled in-
formation in Table 3 will save time in calculating
requirements.

Table 2. Milk production nutrients per pound of milk
of different fat percentages.
Crude
Fat Protein NEL TDN Ca Phos
(%) (Ib) (Mcal) (Ib) (Ib) (Ib)
3.0 .073 .29 .280 .0027 .0017
3.5 .079 .31 .301 .0030 .0018
4.0 .086 .33 .322 .0032 .0020
4.5 .092 .36 .343 .0035 .0021
5.0 .100 .38 .364 .0037 .0023
5.5 .105 .40 .385 .0039 .0024


Feeding The Lactating Herd

Feeding dairy cattle becomes more and more of a
science each year due to a constantly rising level of milk
production. As the level of milk production increases,
either the cow must eat more pounds of feed, or the feed
must contain more nutrients per pound. The latter seems
to have prevailed in recent years. The amount of nutri-
ents has been increased by the addition of an ever


Table 3. Combines requirements for maintenance and milk production at various
different sizes producing 3.5% milk fat (NRC 1988).


levels for cows of three


Daily Nutrient Requirements
Body
Ib Wt CP NEL TDN Ca Phos
Milk (Ib) (Ib) (Mcal) (Ib) (Ib) (Ib)
30 1000 3.35 17.2 16.7 .131 .083
1200 3.55 18.3 17.4 .139 .088
1400 3.74 19.4 18.8 .147 .094
40 1000 4.14 20.3 19.7 .161 .101
1200 4.34 21.4 20.8 .169 .106
1400 4.53 22.5 21.8 .177 .112
50 1000 4.93 23.4 22.7 .191 .119
1200 5.13 24.5 23.8 .199 .124
1400 5.32 25.6 24.9 .207 .130
60 1000 5.72 26.5 25.7 .221 .137
1200 5.92 27.6 26.8 .229 .142
1400 6.11 28.7 27.9 .237 .148
70 1000 6.51 29.6 28.7 .251 .155
1200 6.71 30.7 29.8 .259 .160
1400 6.90 31.8 30.9 .267 .166
75 1000 6.91 31.1 30.2 .27 .17
1400 7.30 33.4 32.4 .28 .18
80 1000 7.30 32.7 31.7 .281 .173
1400 7.69 34.9 33.9 .297 .184
85 1400 8.10 36.5 35.4 .312 .193
90 1400 8.48 38.0 36.9 .327 .202
100 1400 9.27 41.2 40.8 .36 .23
110 1400 10.06 44.2 42.9 .39 .24
120 1400 10.85 47.4 45.9 .42 .26










increasing amount of grain to the ration. This seems to
work so long as the amount of roughage in the ration is
adequate. At some point though, the energy content of
the ration becomes too high and the amount of roughage
too low so that acidosis type conditions occur.

It is common knowledge that early lactating cows do
not eat as much feed as they do at 2-3 months into lac-
tation even though the level of milk production may be
the same. Feed intake lags behind peak milk production
by about 2-4 weeks. This results in a negative energy bal-
ance. Body reserves are mobilized to overcome the energy
deficit which results in some body weight loss. Although
it is normal for high producing cows to lose weight in
early lactation, the energy and especially protein available
from body stores can supply only a limited amount of her
needs. As body fat is mobilized, proportionally more ener-
gy is available than protein. Therefore, the percent pro-
tein in the ration during early lactation should be higher
in order to maximize the efficiency of energy utilization
and to meet the added protein needs.

Feeding cows more liberally in early lactation reduces
the period of time a cow loses body weight (Figure 1).
Such a program has several advantages in that cows peak
in production sooner, attain a positive energy balance
quicker, and have a higher conception rate.

Cows need to be in optimum body condition to achieve
maximum peak yields. For this to occur, mobilization of
body reserves is essential. Each pound of body fat can
provide enough energy to produce 7 lbs of milk of 3.5%
fat. If cows are not in optimum body condition at time of

Periods
1 2 3 4 5


Figure 1. Dry matter intake, milk yield, and body weight
changes and relationships during a lactation cycle.


calving (scores of 3.0-4.0), milk production may suffer.
A condition score of 3.0-3.5 is recommended for first-
lactation heifers and 3.5-4.0 for older cows. As body
condition increases above these scores, calving difficulties
may increase as well as reduced levels of milk in the
subsequent lactation. The same is true for cows having
lower body condition scores.

Phase or group feeding is a common practice in larger
dairies. It is a workable approach to feeding cows since it
provides the manager an opportunity to maximize man-
agement by increasing control over the total system. Phase
feeding may be divided into 5-6 periods based on milk
production, gestation, feed intake, and body weight
(Figure 1).

Moving cows through these phases requires good
records and proper attention being given continuously.
The early lactating cows and high group require the
greatest attention since peak production, good health, and
conception is essential. Fine-tuning the ration in each
phase means more profits. In general, the fresh cows are
maintained in a fresh-cow group for a period of 1-3
weeks and fed more roughage than the high group in
order to avoid possible metabolic problems. Afterwards,
they are moved to the high group and fed free choice for
a period of 100-150 days and longer if performance of the
cow is adequate to keep her in the high group.

Grouping cows by level of milk production and feeding
accordingly appears to be the most effective approach in
controlling feed costs while still achieving maximum milk
production. A well-designed program should not allow
cows to be changed more than 2-3 times in the lactation.
A lot of flexibility may be used in grouping cows, and
some may be similar to the following pattern:

1. Fresh cow group
2. High group
3. Medium-high group
4. Medium group
5. Low group

The question that frequently arises is how to group
first-calf heifers. The first-calf heifer undergoes consider-
able social change at the time of calving when her daily
routine and feeding patterns change, and she is placed
with more mature and aggressive cows. The stress of such
a change is partially reduced by allowing her to move
through the milking barn prior to calving. This gets her
familiar with the new surroundings. Also, there is an ad-
vantage in having first lactation cows with older fresh cows
during the first few days of lactation for closer observa-
tion, ease in training, and developing good milking habits.


Month









After a few days, the first lactation cows should be
placed in a separate group for maximizing intake and pro-
duction. English workers reported an increase in milk pro-
duction of 1,573 Ibs of milk per cow when first-calf heifers
were grouped and fed together compared to those blended
with older cows. Since the greatest advantage is more
likely to occur during the first 120 days of lactation, the
first-calf heifers could be blended with the remaining herd
after 150 days or as soon as desirable. If left together as
a single group for the total lactation, over-conditioning
may become a problem.

Individual cows may vary some from the schematic
drawing shown in Figure 1. Note that weight lost in early
lactation should be regained toward the end of lactation
with less weight gain during the dry period. Cows appear
to be more efficient in gaining weight toward the end of
lactation and less efficient during the dry period.


Feeding The Dry Cows

Nonlactating or dry cows should be properly managed
during the dry period to assure top production in the
subsequent lactations. Most research indicates that a
dairy cow should be given a dry period of 45-60 days.
The greater her production, the more likely that her body
has been depleted of the nutrients used in milk secretion
and the longer the dry period required to replenish the
losses and to store adequate reserves for the next
lactation. Also, the dry period allows the mammary
system time to repair and regenerate, and to gain new
stimulation for lactation as a result of parturition.

Body condition scoring (BCS) is rapidly emerging as an
effective tool in monitoring individual cow energy reserves.
The system most commonly used was developed in
Virginia and scores the cows from 1 to 5, with 5 being the
more obese cow. The objective of BCS is to identify
suboptimal feeding practices and correct them as soon as
possible. The desired score dry off is 3.0-3.5 and at
calving 3.5-4.0. If body condition scores are outside the
above ranges, management steps should be taken to
correct the situation. Dry cow feeding practices should be
aimed toward maintenance of condition scores.

Good body condition at calving is important because
many high producers cannot consume enough feed to
meet their energy needs in early lactation, making it nec-
essary to draw on body reserves during this period. Table
4 shows the nutrient requirements of dairy cows during
the last two months of gestation or during the dry period.


Table 4. Nutrient requirements during the dry period (last
two months of gestation) (NRC 1988).
Body Crude NEL TDN Ca Phos
Wt. (Ib) (Mcal) (Ib) (Ib) (Ib)
900 1.54 9.45 9.21 .059 .036
1200 1.90 11.72 11.43 .079 .048
1400 2.17 13.16 12.83 .092 .056
1500 2.31 13.86 13.51 .099 .060


Ingredients and Their Composition

Table 5 contains a list of the more common feed
ingredients used in Florida. Values given on ingredients
are dry matter (DM), crude protein (CP), bypass protein
(BP), total digestible nutrients (TDN), net energy for
lactation (NEL), fat, calcium (Ca), phosphorus (Phos),
sodium (Na), magnesium (Mg), potassium (K), and sulfur
(S). The TDN and NEL refers to the energy content of
the feed; either may be used in formulating rations.


The Importance of Fiber

The reduction in roughage content of the ration, as a
result of high-grain, is closely related to changes in milk
fat test and has been associated with metabolic problems,
such as acidosis, hoof problems, displaced abomasum,
liver abscesses, and a general decline in health. Adequate
fiber and/or quality forage promotes good health and
better performance.

Terminologies used in describing the fiber content of
rations are crude fiber, effective fiber, acid detergent fiber
(ADF), and neutral detergent fiber (NDF). Both ADF
and NDF are newer ways to describe fiber and will be
discussed later.

The beneficial aspects of feed fiber are primarily due
to its effect on regurgitation (cud chewing), chewing,
salivation, rumen pH (acidity), and rumen function.
Chopping, grinding, or pelleting the roughage tends to
reduce its fiber value and digestibility. Finely ground
roughages may contain little effective fiber.

In feeding lactating cows, there is usually an
economical advantage in using a maximum amount of
forages and byproduct feedstuffs. To be successful, a
maximum level of energy intake must be maintained in
order to maximize production. Finding a consistent
method of identifying the factors that maximize both
intake and production has been the goal of considerable











Table 5. Composition of feeds commonly used in dairy cattle rations (as fed).
NEL
DM CP BP' TDN Milk Fat Ca Phos Na Mg K S
(%) (%) (%) (%) (Mcal) (%) (%) (%) (%) (%) (%) (%)


Alfalfa Hay, early bloom 89 18.0
Alfalfa Hay, full bloom 89 13.0
Alfalfa, haylage 50 8.0
Alfalfa pellets 90 17.0
Alfalfa silage 35 6.0
Bahia hay 88 6.0
Bakery, dried product 91 10.0
Barley, grain 89 11.0
Beet pulp, dried 91 7.2
Bermuda hay (coastal) 89 9.0
Bermuda silage 32 3.8
Bermuda pellets 89 8.5
Blood meal 92 80.0
Brewers grains 91 24.0
Brewers grains, wet 30 7.9
Canola meal (Rapeseed) 91 35.0
Carrot, roots 12 1.2
Citrus pulp 90 6.2
Citrus pulp, silage 20 1.3
Citrus pulp, pelleted 90 6.2
Clover hay, alsike 88 12.3
Clover hay, ladino 90 17.0
Clover-grass mix 88 11.0
Corn meal 89 8.6
Corn, high moisture 72 6.2
Corn, high moisture ear 70 6.7
Corn ear, snapped 89 7.8
Corn silage 30 2.4
Corn cobs, ground 90 2.5
Corn gluten feed 90 21.5
Corn distillers 92 27.0
Corn gluten meal 91 60.0
Corrugated boxes, ground 92 -
Cottonseed, whole 91 22.0
Cottonseed meal 92 41.0
Cottonseed hulls 90 4.0
Cowpea hay 90 16.0
Fats and oils 99 -
Feather meal 90 80.0
Fish meal 90 60.0
Hominy feed 89 10.5
Lespedeza hay 92 12.0
Linseed meal 91 35.0
Malt sprouts 90 25.0
Meat and bone meal 93 50.0
Molasses, cane 70 6.0
Molasses, cane, dehydrated 96 4.8
Millet silage 30 1.8
Milo, grain 88 11.0
Oats, grain 89 11.0
Oat silage 30 3.1
Oat hay 88 7.4
Oats, fresh 20 2.1
Pangola hay 90 6.0
Pea seed, field 90 22.0
Peanut meal 92 50.0
Peanut hulls, coarse 89 6.0
Peanut hulls, pelleted 92 6.0
Peanut skins 90 17.0
Peanut hay 90 8.5


53 2.0 1.40 0.20 0.13
48 1.8 1.30 0.20 0.13
28 1.5 0.70 0.14 0.08
50 1.8 1.40 0.20 0.13
20 1.0 0.50 0.10 0.05
43 1.4 0.30 0.20 0.36
82 13.6 0.05 0.10 0.32
77 1.8 0.04 0.27 0.02
74 0.6 0.62 0.10 0.17
40 1.7 0.30 0.15 0.36
18 0.6 0.16 0.06 0.14
44 0.9 0.35 0.15 0.36
63 1.3 0.29 .24 .32
63 5.3 0.30 0.48 0.24
19 1.7 0.10 0.15 0.07
64 0.68 1.10 -
10 0.2 0.04 0.04 0.12
72 3.0 1.50 0.12 0.09
17 1.6 0.30 0.02 0.02
72 3.0 1.50 0.12 0.09
48 2.4 1.10 0.20 0.40
52 2.5 0.80 0.30 0.10
48 2.8 0.90 0.30 0.10
82 3.5 0.02 0.30 0.01
65 2.8 0.02 0.25 0.01
53 2.4 0.03 0.16 0.03
70 2.9 0.04 0.20 0.04
20 0.09 0.06 -
40 0.4 0.10 0.03 0.01
74 2.2 0.30 0.76 0.90
80 9.0 0.09 0.36 0.09
82 2.2 0.02 0.62 0.02
72 - -
91 21.0 0.14 0.68 0.18
71 3.6 0.15 0.90 0.05
34 1.0 .0.14 0.10 0.27
40 2.5 1.20 0.30 0.24
236 -
64 2.5 0.20 0.72 0.70
64 7.2 5.3 3.1 0.50
83 6.0 0.04 0.60 0.08
42 2.8 0.90 0.20 0.06
74 5.0 0.39 0.82 0.10
67 0.20 0.70 1.10
68 9.6 9.0 4.4 .71
65 1.00 0.08 0.20
82 0.82 0.25 0.15
14 0.08 0.05 0.08
74 2.8 0.02 0.28 0.02
72 4.4 0.05 0.34 0.15
18 1.0 0.12 0.10 0.35
46 2.7 0.22 0.17 0.14
15 0.6 0.06 0.06 0.02
38 1.0 0.30 0.20 0.25
75 1.2 0.10 0.40 0.04
74 1.0 0.20 0.60 0.40
16 1.0 0.20 0.06 0.20
20 1.0 0.20 0.06 0.20
62 16.0 0.34 0.18 0.02
45 3.1 1.00 0.15 0.08


'BP = bypass or escape protein.


.24 2.20
.24 2.20
.14 1.10
.20 2.30
.10 .80
.18 1.30
.32 0.80
.10 0.31
.24 0.18
.15 0.95
.07 0.50
.15 0.95
.22 .09
.12 0.08
.04 0.03
.60 1.20
.02 0.30
.14 0.68
.03 0.11
.14 0.68
.28 2.10
.40 1.80
.35 2.10
.09 0.26
.08 0.24
.09 0.29
.11 0.36
.08 0.31
.06 0.75
.30 0.60
.06 0.18
.13 0.41

.27 0.82
.50 1.20
.32 0.90
.35 1.70

.20 0.27
.17 0.70
.23 0.60
.22 0.90
.60 1.20
.18 0.20
1.00 1.32
.58 4.00
.40 3.50
.10 0.40
.16 0.32
.16 0.36
.12 0.60
.13 1.20
.08 0.35
.15 1.20
.10 1.00
.02 1.10
.15 0.90
.15 0.90
.11 0.78
.44 1.20


.24
.24
.17
.24
.12
.10
.02
.15
.20
.26
.03
.26
.34
.34
.11
.09
.02
.06

.06
.14
.18
.18
.12
.10
.12
.15
.02
.36
.20
.42
.40

.29
.38
.23
.20

1.40
.45
.02
.16
.03

.25
.87
.50
.04
.16
.20
.02
.15
.01
.10
.15
.29
.08
.08
.15
.20










Table 5. Continued
NEL
DM CP BP' TDN Milk Fat Ca Phos Na Mg K S
(%) (%) (%) (%) (Mcal) (%) (%) (%) (%) (%) (%) (%)
Ryegrass silage 28 2.5 22 16 17 0.5 .18 .08 0.02 .04 0.40 .05
Ryegrass hay 90 10.0 30 54 56 1.8 .54 0.27 0.08 .12 1.40 .15
Rye seed, grain 89 12.0 40 74 74 2.1 0.06 0.32 0.02 .12 0.47 .15
Rye silage 28 3.4 25 16 16 1.0 0.10 0.10 0.30 .10 0.60 .02
Rice bran 91 12.4 35 60 62 12.0 0.06 1.40 0.02 .90 1.70 .18
Rice hulls, ground 92 2.8 60 15 10 0.9 0.08 0.06 0.12 .01
Rice millfeed 90 6.0 30 30 32 3.0 0.08 1.30 0.05 .35 0.90 .09
Sorghum, grain, silage 30 2.4 50 18 17 0.09 0.05 0.01 .09 0.46 .01
Sorghum, forage silage 30 2.1 50 17 16 0.08 0.05 0.01 .08 0.40 .01
Soybean meal 89 44.0 28 74 76 4.5 0.30 0.65 0.27 .26 1.90 .40
Soybean meal 89 48.0 25 74 76 0.8 0.30 0.65 0.27 .26 1.90 .40
Soybean hulls 91 11.0 10 68 70 2.0 0.40 0.15 0.04 .14 0.72 .09
Soybeans 90 37.0 26 84 89 18.0 0.30 0.65 0.28 .26 1.90 .42
Soybean silage 32 17.0 40 17 16 1.0 0.40 0.15 0.02 .12 0.30 .09
Soybean hay 88 13.0 30 45 46 2.4 1.10 0.18 0.10 .26 0.80 .20
Sudex silage 26 2.1 30 13 12 0.8 0.07 0.05 0.01 .06 0.42 .04
Sugarcane bagasse 92 1.8 40 40 35 0.80 0.20 0.18 .08 0.40 .09
Sugarcane silage 30 0.8 0 19 18 0.07 0.05 0.04 .04 0.70 .03
Sunflower meal 90 28.0 30 58 62 1.0 0.40 1.00 1.00 .60 0.90 .25
Sunflower meal 90 40.0 30 64 65 1.0 0.40 1.00 1.00 .70 1.00 .25
Urea 99 281.0 0 -
Wheat, whole 89 12.6 22 78 82 1.6 0.05 0.34 0.02 .10 0.42 .15
Wheat, midds 89 16.0 21 76 74 4.5 0.10 0.90 0.17 .50 1.20 .16
Wheat silage 26 3.0 30 18 16 1.0 0.07 0.07 0.02 .16 0.36 .06
Whey, lacto 61 44.0 0 68 70 0.18 0.44 0.74 .07 1.20 .04
Whey, dehydrated 93 13.0 0 72 75 0.90 0.72 1.00 .12 1.10 .95
Yeast, brewers 93 44.0 42 72 75 1.0 0.12 1.40 0.07 .20 1.70 .38
'BP = bypass or escape protein.


research. Dairymen have realized for years that more
grain must be fed with poor quality forage than good
quality forage to get the same amount of milk. Scientists
have attempted to develop a similar system by using fiber
as the measurement. In the newer system of identifying
fiber, the fiber content of the feedstuff has been named
according to the laboratory procedure, namely, acid
detergent fiber and neutral detergent fiber. NDF is the
more complete measure of total fiber since it measures all
the cellulose, lignin, and hemicellulose. Crude fiber
measures only cellulose and some lignin, whereas ADF
includes cellulose and all the lignin. For this reason, ADF
appears to be more closely associated with digestibility
and NDF with rumen fill or dry matter intake. Dry
matter intake and milk production are highly correlated so
any component of the ration affecting dry matter intake
would affect milk production.

Table 6 shows the optimal diet NDF levels suggested
by Wisconsin workers and slightly modified for various
levels of milk production when using silage and hay base


Table 6. Suggested optimal NDF levels as a percent of
total ration dry matter at various production levels'
3.5% Milk (Ib) Optimal NDF Percent
65 or more 28-32
45-65 33-36
31-45 35-39
less than 30 40-45
dry cows 45-50
'Mertens, D. R. 1982. Proc. Ga. Nutr. Conf. pp. 116-126.

rations. With cottonseed hull base rations, increase NDF
by 3-5 percentage units (30% vs. 35%).

The use of neutral detergent fiber values may be useful
in purchasing hay and balancing rations for high producing
cows. The use of NDF values should be used only as a
guide since particle size, length of cut, effectiveness of
fiber, and palatability are not measured by NDF but are
also important considerations in formulating rations for
dairy cows. Cottonseed hull rations may need to be
adjusted upward when using NDF values since they have
a greater rate of passage than hay containing rations.











Table 7. Composition of feeds commonly used in dairy cattle rations (as fed).
Effective Crude
Crude Fiber Fiber ADF NDF
--------------% --------------
Alfalfa Hay, early bloom 28.0 23.0 29 38
Alfalfa Hay, full bloom 38.0 30.0 34 45
Alfalfa, haylage 20.0 16.5 17 23
Alfalfa pellets 12.0 25.0 34 44
Alfalfa silage 14.0 8.0 12 14
Bahia hay 42.0 31.0 34 65
Bakery, dried product 1.0 1.0 11 16
Barley, grain 5.2 5.2 6 17
Beet pulp, dried 20.0 19.0 29 48
Bermuda hay (coastal) 40.0 32.0 36 65
Bermuda silage 15.0 10.0 12 20
Bermuda pellets 15.0 31.0 31 63
Blood meal 1.0 1.0 3 5
Brewers grains 14.0 14.0 21 41
Brewers grains, wet 6.0 5.0 7 14
Canola meal (Rapeseed) 12.0 11.7 15 32
Carrot, roots 0.7 0.7 -
Citrus pulp 12.0 12.0 19 21
Citrus pulp, silage 4.5 4.2 5 6
Citrus pulp, pelleted 9.0 12.0 19 21
Clover hay, alsike 35.0 25.0 31 36
Clover hay, ladino 35.0 26.0 28 32
Clover-grass mix 38.5 30.0 35 52
Corn meal 2.0 2.0 2 8
Corn, HM 1.4 1.0 1 6
Corn dust, pellets 6.0 6.0 7 14
Corn, HM ear 5.6 5.6 2 8
Corn ear, snapped 8.0 8.0 10 25
Corn silage 12.0 7.4 10 16
Corn cobs, ground 41.0 31.5 35 75
Corn gluten feed 8.0 8.0 11 40
Corn distillers 12.0 12.0 15 38
Corn gluten meal 3.0 3.0 4 12
Corrugated boxes, ground 65.0 65.0 72 90
Cottonseed, whole 19.0 17.0 31 40
Cottonseed meal 11.0 11.0 17 24
Cottonseed hulls 43.0 43.0 66 81
Cowpea hay 42.0 24.0 36 45
Feather meal 5.0 2.0 2 17
Fish meal 1.0 1.0 2 4
Hominy Feed 5.0 5.3 12 40
Lespedeza hay 42.0 28.0 36 56
Linseed meal 9.0 9.0 15 20
Malt sprouts 5.0 8.0 12 26
Meat and Bone meal 3.0 2.2 4 7
Molasses, cane -
Molasses, cane, dehydrated -
Millet silage 10.0 7.0 9 12
Milo, grain 2.0 2.0 5 15
Oats, grain 10.0 10.0 14 28
Oat silage 8.0 6.5 4 10
Oat hay 38.5 28.0 35 54
Oats, fresh 5.2 5.0 6 10
Pangola hay 45.0 31.0 39 68
Pea seed, field 9.0 5.0 18 12
Peanut meal 4.0 4.0 5 11
Peanut hulls, coarse 50.0 50.0 58 65
Peanut hulls, pelleted 20.0 50.0 58 65
Peanut skins 18.0 12.0 18 25
Peanut hay 38.0 31.0 36 45










Table 7. Continued
Effective Crude
Crude Fiber Fiber ADF NDF
-------------- --------------
Rye seed, grain 3.0 3.0 3 6
Rye silage 11.0 9.0 12 15
Rice bran 10.9 10.0 16 29
Rice hulls, ground 35.0 40.0 64 73
Rice millfeed 12.0 18.0 25 30
Sorghum, grain, silage 12.0 9.8 12 19
Sorghum, forage silage 10.0 9.0 13 23
Soybean meal 5.0 5.0 6 12
Soybean meal 4.0 4.0 5 9
Soybean hulls 14.0 34.0 41 57
Soybeans 5.0 5.0 9 14
Soybean silage 12.0 8.0 13 18
Soybean hay 38.0 25.0 36 45
Sudex silage 10.0 7.0 8 14
Sugarcane bagasse 45.0 45.0 54 75
Sugarcane silage 13.0 8.0 12 15
Sunflower meal 26.0 26.0 30 36
Sunflower meal 11.0 11.0 14 16
Wheat, whole 2.0 2.0 4 10
Wheat, midds 6.0 7.0 9 32
Wheat silage 11.0 8.0 10 15
Yeast, brewers 3.0 3.0 5 9


Special Ingredients and Characteristics


- Contains a reduced amount of
effective fiber when finely ground.
Considered a low-energy ingredient.

- Levels of 8-12 lbs per cow provide
excellent fiber. Higher levels,
depending on quality, tends to
reduce milk production.

- Stale bread, crackers, and other bak-
ery waste are frequently available.
Such waste can be used to replace a
part of the grain. Maximum level
suggested is 15% of ration. Limited
studies indicate the value of 91%
DM bakery waste to be near corn in
energy.

- An excellent cereal grain used for
feeding all classes of livestock.
Barley and oats need to be rolled or
ground for dairy cattle.

- Used primarily in simple stomach
animal rations but may be used in
ruminant rations. A high-protein
feedstuff with 80% bypass protein.


Brewers
grains



Brewers
(wet)



Citrus pulp,
pelleted




Cottonseed


- A low-energy, medium-protein
palatable ingredient that contains
medium bulk. Maximum levels
suggested are 20-25% of rations.

- Wet brewers grains vary in dry
matter content (avg. 25% DM).
Levels commonly fed are 20-40 lbs
daily per cow.

- Pelleted citrus pulp and regular
citrus pulp are similar in value
except for a slight difference in
effective fiber. Optimum levels
suggested are 20-30% of ration.

- A high-energy, medium-protein in-
gredient fed without processing to
dairy cows. Research suggests levels
of 5-10 lbs daily per cow are accep-
table. Adequate fiber is needed in
the ration. Use with oilmeals other
than cottonseed meal since gossypol
level may become quite high.


Alfalfa
pellets


Bahia,
Bermuda,
and Pangola
hay

Bakery
waste







Barley




Blood meal











Distillers
dried grains




Feather
meal





Meat and
bone meal





Oats




Peanut
hulls





Peanut
skins


Using Mineral Supplements

Various mineral supplements are available and
frequently used in formulating rations. A list of
commonly used supplements is shown in Table 8.


- A medium-protein feedstuff ob-
tained after the removal of ethyl al-
cohol by distillation from the yeast
fermentation of grain. Optimum lev-
els suggested are 15-25% of ration.

- A high-protein, medium-energy
product of the poultry industry.
Contains 60-70% escape protein.
Use in quantities of 2-5% of dry
matter since high levels may
decrease dry matter intake.

- Meat and bone meal is high in pro-
tein and escape protein as well as
minerals. May be used for high-
producing cows. Other sources of
protein are generally more eco-
nomical and give similar results.

- An excellent cereal grain used for
feeding all classes of livestock. Oats
need to be rolled or ground for
dairy cattle.

- High in fiber; low in energy and
protein. Must be well-textured to
have a high effective fiber value.
Use in limited quantities or to
extend other fiber sources. Pelleted
hulls are low in effective fiber.

- The outer covering of the peanut
kernel that may contain some
broken peanuts. Contains excellent
bulk and frequently improves flow
problems. Suggested levels are
5-10% of ration due to their fairly
high content of tannin.


Poultry
litter







Soybean
hulls



Soybean,
seed






Wheat






Whey, lacto


Considerable work has been done in recent years to
better establish the mineral needs of high producers and
to define the role of minerals in nutritional biochemistry.
Table 9 shows the current levels of the major or macro
minerals recommended for dairy cattle rations.


- Prohibited in Interstate Milk
Shippers resolution from being used
in lactating cow rations. Palatability
problems encountered where high
feed intake is desired. Heifer
rations may contain from 10 to
15%. Use laboratory analysis to
establish composition values.

- The outer covering of the soybean.
The 30-35% fiber hull contains on-
ly 12-14% effective fiber. Suggest-
ed levels are 10-20% of rations.

- Commonly processed and used as
soybean meal. May be used as
whole soybeans or rolled for better
utilization. Finely grinding soybeans
may cause oil and gummy problems.
Crush or roll soybeans for best
results.

- An excellent cereal grain for all
livestock. Suggested levels are 20-
35% of total ration. Wheat must be
rolled or ground. Wheat ground too
fine is less palatable due to floury
meal and pasty mass in the mouth.

- A liquid product containing 44%
protein, of which 42% comes from
ammonium lactate. Maximum levels
suggested are 2-3 lbs daily per cow,
or 15% or less of the concentrate.










Table 8. Mineral supplements and their mineral composition.
Supplement Ca Phos K Mg S Na
------------- %-------------
Calcium carbonate 38.0 -
Limestone, ground 33.0 -
Oyster shell flour 33.0 -
Tricalcium phosphate 38.0 18.0 -
Monocalcium phosphate 20.0 21.0 -
Deflourinated phosphate 32.0 18.0 -
Dicalcium phosphate 26.0 18.0 -
Disodium phosphate 21.6 -
Salt (NaCI) 39.3
Steamed bone meal 28.0 14.0 -
Sodium bicarbonate (NaHCO,) 27.4
Diammonium phosphate' 20.0 -
Monoammonium phosphate2 24.0 -
Monosodium phosphate 25.0 -
Sodium, Tripoly phosphate 25.6 -
Biofos 18.0 21.0 -
Dyna-K 50.5 -
Dynafos' 22.0 18.5 -
Dynamate 18.5 11.6 22.3 -
Dufos3 JDiammonium phosphate) 20.0 -
Dikal 21 19.0 21.0 -
Magnesium oxide 60.0 -
Potassium chloride 52.4 -
'Compound contains 18.0% nitrogen or 112.5 protein equivalent.
2Monoammonium phosphate (monofos) contains 68.75% protein equivalent (11% nitrogen).
Trade names of products available in abundance in Florida. Mention of a trade name, proprietary product or specific equipment
does not constitute a guarantee or warranty by the Dairy Science Department, Institute of Food and Agricultural Sciences, or the
University of Florida and does not imply its approval to the exclusion of other products that may be suitable.


Using Trace Minerals and Vitamins

The addition of trace minerals and certain vitamins to
dairy cattle rations is usually considered to be good nutri-
tional insurance. Yet, the question arises: "How do I know
which trace minerals, and how much of each, to add?"
The trace minerals deserving some consideration as
possible additions to dairy rations are shown in Table 10.
Trace minerals are needed by the dairy animal in very
small quantities (parts per million). For this reason, salt
is commonly used as a carrier for all the trace minerals.
Trace minerals should not be added to dairy rations
indiscriminately. Many rations will contain adequate levels
with or without their addition. If a trace mineral problem
is suspected, examine the situation and make appropriate
adjustments in the mineral mixture. Too much of a
particular mineral could further antagonize the situation.

Vitamins deserving consideration under Florida condi-
tions are vitamins A, D, and E. A 1400-lb cow consuming
40 lbs of dry matter daily needs about 65,000 USP units of
vitamin A, 18,000 units of vitamin D, and 280 units of vit-
amin E. Dry cows should receive 50-100,000 units or


Table 9. Major mineral and vitamin content recommended
in rations for hiah producers (dry matter basis).


Current Desirable NRC
Mineral In Rations (%) 1988 (%)
Calcium 0.65-0.80 .65
Phosphorus 0.42-0.50 .42
Magnesium 0.28-0.35 .25
Potassium' 1.00-1.50 1.00
Sulfur 0.20-0.25 .20
Sodium' 0.40-0.67 .18
Vitamin A 1400-2000 IU/lb 1450 IU/lb
Vitamin D 450-500 IU/lb 450 IU/lb
Vitamin E 7-10 IU/lb 7 IU/lb


'Recent studies at Florida showed an increased need for potassium
(K) and sodium (Na) in hot weather or stress periods. The highest
level of milk production was obtained when the total ration dry
matter contained about 1.5% K and 0.67% Na

more of vitamin A per day when green forage is not avail-
able and 20,000 units or more if green forage is available.

Certain stress factors, such as hot climate, nitrate in
feeds, disease, and lactations, may increase the vitamin A
requirements of the animal. In order to avoid a vitamin
A deficiency in reproduction, the dairy ration should
provide from 40,000 to 80,000 USP units of vitamin A.











Some dairymen feed little vitamin A during the green
forage feeding period and about 100,000-150,000 units per
cow during hot weather (see Fact Sheet DS-27 Vitamin
Needs of Dairy Cattle for more details).

Pasture Forage Evaluation

Grazing dairy cattle on pasture grasses and legumes is
a common practice in many areas of the country. Forages
(hay, pasture, and silage) play a vital role in meeting the
nutrient requirements of dairy cattle and many dairymen
may use all three forms of forages.

The quality of pasture or green chop forage varies con-
siderably throughout the year. This variation in quality
becomes exceedingly important where large quantities of
forages are fed. The contribution that pasture forages can
make in meeting the nutrient requirements for high pro-
ducers is affected by both the quality and quantity of for-
age. Care must be taken to avoid overestimating both
the quality and quantity of forage intake or underfeeding
may result, causing a drop in milk production.


Table 10. Suggested trace mineral content of rations
(DM) for lactating dairy cattle (NRC-1988).
Approx. Ration
Concentration
Mineral (Dry Basis)

Iron 50.0 ppm
Manganese 40.0 ppm
Copper 10.0 ppm
Zinc 40.0 ppm
Cobalt 0.1 ppm
Iodine 0.6 ppm
Selenium 0.3 ppm

A laboratory analysis is useful in determining the
nutrient value of stored feeds. The use of green forages,
however, presents a different problem since quality varies
with maturity and some plants mature at a rapid rate.
Even so, with good knowledge and an accumulation of
data from forages being analyzed, the nutrient content of
the forage can be estimated fairly close to the real value.
The values in Table 11 are averages accumulated from
Florida forages which were tested in laboratories.


Table 11. A summary of the results obtained in the forage testing program in Tallahassee, FL hay, silage,
and green chop (as fed).
Crude
DM CP Fiber TDN NEL
Sample Name Number (%) (%) (%) (%) (Mcal)

A. HAY


Aeschynoneme
Alfalfa
Bahia
Argentina
Pensacola
Bermuda
Alicia
Callie
Coastal
Coastcross
Unspecified
Bluestem
Clover
Alyce
Ladino
White
Carpetgrass
Crabgrass
Elephant grass (dwarf)
Hairy Indigo
Hemarthria Altissima
Indiangrass
Maidencane
Millet


8 87.9 11.5 30.8 43.0
32 90.8 16.0 25.8 54.2


61 91.5
24 91.0


90.6
91.4
92.0
90.0
91.0
92.0

90.4
92.4
90.0
91.5
91.8
90.0
90.0
90.0
91.2
92.1
91.0


7.0 28.0 45.4
5.8 28.0 43.5


29.2
30.7
21.5
31.0
29.8
30.0

35.6
33.0
35.8
26.6
'32.0
29.5
36.8
32.5
31.5
30.0
30.1


31.5
45.6

33.4
32.0

33.2
35.0
40.0
34.2
31.0
32.0

31.0
32.0
30.1
36.1
29.0
48.0
24.6
30.1
32.5
36.0
35.1











Table 11. Continued


Sample Name
Oats
Pangola
Peanut, forage
Peanut, Perennial
Peavine
Rye
Ryegrass
Sorghum Sudan (Sudex)
Soybean
Stargrass
Torpedo


B. AVERAGE SILAGE ANALYSIS
Corn
Bermuda
Callie
Coastal
Hermathria
Millet
Pangola
Small Grain
Oat
Rye
Sorghum, forage
Sorghum, grain
Sorghum, Sudan (Sudex)

C. AVERAGE GREEN CHOP ANALYSIS
Aeschynoneme
Alfalfa
Hermathria grass
Bahia
Bermuda
Elephant grass (dwarf)
Maidencane
Millet
Rye
Sorghum Sudan
Torpedo
Wheat


170 28.0 2.4 7.0 19.1


35.0
34.0
31.0
24.0
27.0

31.0
30.0
28.0
28.0
23.0


31.2
18.0
29.0
25.0
27.0
20.0
35.0
15.0
20.0
20.2
34.0
26.0


19.9
18.1
17.8
11.8
12.8

18.0
17.2
15.0
17.0
13.0


14.5
9.1
15.4
14.6
15.0
12.5
16.0
7.6
12.8
10.2
17.2
18.0


The protein content of forages is easily influenced by
the level of fertilization. For this reason, one can
anticipate some variation in the protein content as
compared to the average figures given in the above table.

After one has arrived at a realistic figure to place on
the quality of the forage, the quantity to be fed becomes
the next important step. If the forage is green chopped
and fed in a bunk, the amount fed per cow can be
calculated. Generally, this can be accomplished by either
weighing the wagon, estimating the amount on the wagon,
or weighing short sections of the forage placed in the
bunk and calculating the amount available per cow. In


order to have a good feeding program, the dairyman
needs to know the average forage consumed per cow.
Too many dairymen ignore this part of their feeding
program.

Pasture consumption from grazing may be more
difficult to estimate (Table 12). Generally, for high
producers receiving grain, consumption will vary from 30
to 100 lbs per cow per day. The wide variation in
consumption is due to pasture quality and the quantity
available. Also, the season of the year has a great
influence on pasture consumption. During the hot
summer months, pasture consumption may drop 25-40%.


Number
23
166
6
12
5
6
8
4
7
8
6


DM
(%)
90.0
91.8
92.0
92.0
91.4
92.3
91.0
91.3
90.4
91.4
91.4


CP
(%)
7.2
5.0
8.2
13.0
6.7
8.2
9.0
5.4
8.8
7.3
5.5


Crude
Fiber
(%)
28.0
29.9
38.3
24.0
39.2
32.0
28.0
32.8
33.5
29.1
30.5


TDN
(%)
41.0
41.6
40.0
54.0
39.0
47.6
52.6
46.2
45.1
53.7
47.6


NEL
(Mcal)
38.0
29.5
31.6
44.0
31.0
34.4
40.6
32.7
31.6
43.4
34.6


16.4

15.7
14.0
14.0
9.0
9.2

16.0
13.4
13.5
15.0
10.0


13.0
7.0
11.6
12.0
12.0
10.6
14.0
5.8
11.0
7.5
15.4
16.5










Table 12. Estimated pasture consumption per day (as
fed).

P e Pasture Condition
Pasture
Forage Excellent' Good2 Fair' Scanty4
---------(Ibs)----------
Bahia 70 50 30 20
Bermuda 75 60 35 25
Clovers 90 70 45 30
Millet 90 70 50 30
Oats 90 70 50 30
Rye 90 70 50 30
Pangola 75 60 35 20
Ryegrass 90 65 40 25
Sudex 90 70 50 30
'A pasture furnishing an abundance of lush, actively growing
palatable forage.
A pasture that provides good grazing. The cows are able to get a
Jill easily. Most of the grasses should have a good green color.
A pasture that has good growth but has weeds. Also a pasture that
is rather dry because of lack of rain.
An overgrazed pasture or where the pasture is dry and short.

The consumption values in Table 12 may be obtained
where cows are allowed to graze for one to two hours per
day. Cows will obtain their greatest consumption in the
first 30 minutes of grazing; by the end of one hour, they
will have a good fill. Cows remaining on winter or
summer annual grasses beyond one hour will cause dam-
age to the plants by trampling.
Dairy cows will usually remain on permanent pastures
such as bahia, bermuda, and pangola for longer periods.
After establishing an estimated value for the quality and
quantity of pasture or green chop being consumed, the
formulation may be completed through computer usage or
extensive hand calculations.


Formulating Rations

A number of ingredients may be used very successfully
in dairy cattle rations so long as a good balance is
maintained and certain limitations and economic factors
are carefully considered. Several are listed in Table 13.

Relative Values
Relative values are based on prices set for corn, soybean
meal, and cottonseed hulls or similar ingredients that may
be used to replace them.
High producers will generally produce 2-4 lbs more
milk daily when on rations containing a good balance of
protein as compared to cows on rations containing mostly
protein from highly soluble sources. For this reason,
researchers have shown that urea and other nonprotein


Table 13. Relative values and limitations on certain
ingredients.


Alfalfa hay
Brewers, dried
Bermuda hay
Citrus pulp
Cottonseed, whole
Cottonseed meal
Distillers grains
Hominy feed
Milo grain
Molasses, cane
Oats or Barley
Soy hulls
Peanut meal
Wheat midds
Wheat, grain


Relative'
Value/ton
($)
120
146
81
99
163
196
167
119
111
85
112
108
223
130
123


Most
Efficiency
Max/ton
(%)
15-30
10-20
10-15
15-30
10-12
10-20
20-30
30-40
20-30
5-8
15-30
15-25
10-20
10-25
20-35


'Prices based on corn at $110, 44% soybean
cottonseed hulls at $75 per ton.


Bypass
Values for
Protein
(% of CP)
25
49
20
25
25
35
47
25
45
0
17
25
25
21
22


meal at $210, and


nitrogen sources may be utilized in some rations and are
of little to no value in others.

Bypass Protein Values

The optimum concentration of bypass protein as a
percent of total protein for the total ration dry matter is
probably between 30-40%. Rations formulated within
these ranges should provide adequate protein or amino
acids for absorption from the small intestine.


Understanding Dry Matter
Consumption by Dairy Cows

Many factors influence the dry matter (DM) intake of
high producers. Those commonly observed are body
weight, health of cows, level of milk production, climate,
frequency of feeding, ration balance, and palatability of
the ration.
The dry matter intake for high producers varies
according to type of ration and can range from 2.5 to 5 lbs
of dry matter per 100 lbs of body weight.
Tables 14 and 15 contain information on DM intake for
cows of various sizes producing different levels of milk.
Forages vary considerably in protein and energy. Where
stored forages are used in abundance, a forage test should
be conducted periodically.










Table 14. Dry matter intake on various rations in Florida.
DM Daily
Intake Milk Wt.
(% body Milk Fat Gain
Treatment wt) (Ib) (%) (Ib)
Ensiled complete
ration 3.1 41.1 4.80 .99
Ration blended
at feeding 3.2 41.6 4.80 .79
Silage and concentrate
fed separately 3.1 42.5 5.0 1.30
Complete (bagasse) feed 3.9 47.8 4.1 1.10
Complete (CS hulls) feed 4.1 50.2 3.80 .75


Table 15. Estimated DM intake at various levels of
production and body weight (4% FCM).'
FCM Body Weight of Cows (Ib)
(Ib/day) 900 1100 1300 1400
20 2.6 2.3 2.1 2.1
40 3.4 3.1 2.8 2.7
60 4.1 3.7 3.4 3.2
70 4.6 4.0 3.6 3.5
80 5.1 4.3 3.8 3.7
90 5.5 4.7 4.1 3.9
100 5.0 4.4 4.2

'NRC 1988; FCM = fat correct milk

Formulating Dairy Rations

Rations are nutritionally balanced and formulated to
meet the nutrient requirements of animals performing at
different levels. The nutrient requirements for main-
tenance and milk production for different sized animals
including energy, protein, calcium, and phosphorus.
Consider the following example where a herd receives
a known amount of corn silage as the primary roughage.
First the crude protein (CP) and total digestible nutrients
(TDN) of the roughage are determined and subtracted
from the requirements. The remainder will need to be
supplied by the concentrate as shown below.

Example: The use of corn silage and a purchased
concentrate.
Ib CP TDN Ca P
(Ib) (Ib) (Ib) (Ib)
Requirements
(80# Milk) 7.69 33.9 .290 .184
Provided by corn silage 50 1.20 10.0 .045 .030
Needed by concentrate 6.49 23.9 .255 .154
Provided by concentrate 34.5 6.90 24.2 .276 .172
(70% TDN, 20% CP,
.80% Ca, .50% P) + + + + +


The purchased concentrate should contain about 20%
crude protein, 70% TDN, 0.80% Ca, and 0.50% phos-
phorus so that the 34.5 lbs of concentrate provide the
needed requirements. Most concentrates contain about
70% TDN.
Calculations: 23.9 lbs TDN needed + .70 (TDN) = 34.2
lbs of concentrate required.

6.49 lbs needed CP + 34.2 lbs concentrate = .19 or 20.0%
protein needed in concentrate.


Cation-Anion Concept
In Balancing Rations

In recent months, the concept of cation-anion balancing
of rations has received an increasing amount of interest.
Cations are minerals that have a positive charge and
anions have a negative charge. A list of the minerals that
are of greatest interest are in Table 16.

Table 16. Minerals useful in calculating the cation-anion
balance in rations.
Molecular Equivalent meq.
Wt. Wt. Wt.
Mineral (grams) Charge (grams) (grams)
Sodium 23 +1 23 .023
Potassium 39 +1 39 .039
Calcium 40 +2 20 .020
Magnesium 24 +2 12 .012
Chloride 35.5 -1 35.5 .0355
Sulfur 32 -2 16 .016
meq. = milliequivalent

A cation-anion balance is calculated by subtracting
anion milliequivalents from cation milliequivalents (meq.).
While several formulas have been used by poultry
producers, the following is suggested:

[Cation-anion balance equals meq of sodium plus
potassium minus meq. of chlorine plus sulfur]

Here is a sample calculation for a dry cow ration
containing 0.8% potassium, 03% sodium, .35% chlorine
and .2% sulfur.
Sodium: 0.3 grams per 100 grams of ration dry matter
(0.3%) divided by .023 meq. per gram (Table 16) equals
+13 meq. of sodium per 100 grams of feed.
Potassium: 0.8 grams per 100 grams of ration DM
divided by 0.039 meq. per gram equals +20.5 meq. of
potassium per 100 grams of feed.










Chlorine: 035 grams per 100 grams of ration DM
divided by 0.0355 meq. per gram equals -9.9 meq. of
chlorine per 100 grams of feed.

Sulfur: 0.2 grams per 100 grams of ration DM divided
by .016 meq. per gram equals -12.5 meq. of sulfur per 100
grams of feed.

The cation-anion balance would be the summation of
the above charges: +13, +20.5, -9.9, -12.5 = +11.0
meq./100 grams DM. The ration contains a greater
amount of cations than anions.

Studies to date report less milk fever when cows are
being fed on a low-cation or high-anion balanced diet
during the dry period. British researchers reported that
rations with an excess of anions resulted in positive
calcium balance. Results of two experiments are in Table
17.

Table 17. Incidence of milk fever noted when using
different cation-anion balanced rations in the dry period.
Cation-Anion
Balance Incidence
Station (Milliequivalent) (Milk Fever)

Canadian +33.0 47.4
-12.9 None
Colorado -4.8 4.0
+19.0 17.0
'M. F. Hutjens, Hoards Dairymen, Sept. 10, 1988.

Lactating cows seem to respond more to a positive
cation-balanced ration whereas the opposite appears to
be the case for dry cows. Kentucky workers reported that
milking cows fed a ration containing a +20.0 meq. per 100
grams produced 8.6% more milk than cows having a -
10.0 cation-anion balanced ration.
Present research indicates that watching the cation-
anion balance may have potential for improving milk yield
and reducing the incidence of milk fever. Research is
underway at the University of Florida to help in defining
the parameters needed in making recommendations.

The Carbohydrate Approach

Balancing rations according to the amount of starch or
soluble carbohydrates in the ration of high producing cows
may be the buzz word for the 90s. It appears that proper
management of carbohydrate feeding can have an effect


on herd performance. The challenge is to maximize the
energy content of the ration without increasing the
incidence of metabolic problems. Diets that contain too
much fiber or poor quality forage is likely to limit energy
intake and milk production. At the same time, rations
that contain too much soluble carbohydrates such as corn,
high-moisture corn, and wheat may lead to acidosis,
depressed fiber digestion, reduced feed intake, and milk
fat depression. Such rations affect peak milk yield,
persistency in the herd, and may lead to increased
reproductive problems.

Carbohydrates are compounds such as sugars, starches,
and cellulose (Figure 2). The composition and digest-
ibility of the carbohydrate fraction of feedstuff varies
considerably depending on maturity and processing of the
feedstuff. Some carbohydrates are degraded very rapidly
in the rumen whereas others are more slowly digested.
The key is having the right balance in the ration.

The structure of carbohydrates is divided into two
components: cell wall and noncell wall fractions. They
are termed structural and nonstructural carbohydrates.
The amounts of starch and sugars recommended in dairy
cattle rations varies from a low of about 30% to a
maximum of 45% of the ration dry matter.

A simple formula for determining the amount of
nonstructural carbohydrates (NSC) in various feedstuffs
is as follows: (100) (NDF, crude protein, fat, and
minerals [ash]) = NSC value. Several feedstuffs are
shown in Table 18.

It is important that rations be designed to promote
microbial balance in the rumen. Dry matter intake
declines with too much energy in the ration and too much
fiber limits intake. An abundance of starches and sugars
in the diet may shift the fermentation patterns in the
rumen toward lactic acid fermentation that would lead to
acidosis and low fat testing milk.

The most critical period in the cow's lactation is from
parturition until peak production which takes from 5 to 8
weeks postpartum. It is during this period that the "stage
is set" for obtaining the highest possible peak in
production and also for the onset of normal reproductive
cycling which may occur as early as 2-3 weeks in some
cows. To be successful, the best strategies must be
applied that include many areas such as feeding and
management practices, quality and balance of feed, feed
bunk management, milk practices, and the maintenance of
good health.



























Figure 2. The Components of the Carbohydrates


Table 18. Carbohydrate fractions of selected feedstuffs (DM basis).
Crude Ether
Protein Extract Ash NDF NSC'
Feedstuff (%) (%) (%) (%) (%)
Forages
Alfalfa hay 20.0 3.6 9.6 40.0 26.8
Bermuda hay 12.0 3.2 7.2 68.0 9.6
Corn silage 8.0 3.0 4.1 48.0 36.9
Concentrates
Barley 11.9 1.5 2.9 28.0 55.7
Brewers grains 28.0 7.0 3.4 45.0 16.6
Citrus pulp 7.0 6.0 5.2 21.0 60.8
Corn distillers 29.0 10.5 4.8 42.5 13.2
Corn grain 10.8 4.2 1.5 9.0 74.5
Cottonseed meal 44.5 2.0 6.2 34.0 13.3
Cottonseed, whole 22.4 23.3 4.8 44.0 5.5
Oats grain 15.6 2.1 3.0 32.2 47.1
Peanut meal 52.0 1.4 6.3 14.0 26.3
Soybeans 42.8 18.8 5.5 24.0 8.9
Soybean hulls 12.5 1.0 4.2 68.5 13.8
Soybean meal 48.5 1.5 7.3 27.0 15.7
Wheat grain 14.5 1.9 1.8 14.0 67.8
Wheat midds 17.4 4.3 5.5 35.6 37.2

'NSC = nonstructural carbohydrate = 100 (CP + EE + ash + NDF)
NDF = Neutral detergent fiber


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manufacturers, county extension personnel and others interested in feeding dairy cattle. 5-3M-90

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