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Title: Range Cattle REC newsletter
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Permanent Link: http://ufdc.ufl.edu/UF00089215/00015
 Material Information
Title: Range Cattle REC newsletter
Series Title: Range Cattle REC newsletter
Physical Description: Serial
Creator: Range Cattle Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida
Publisher: Range Cattle Research and Education Center, University of Florida
Publication Date: March 2003
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Bibliographic ID: UF00089215
Volume ID: VID00015
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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University of Florida, IFAS
Range Cattle Research and Education Center
March 2003
Volume 6, Number 1


Calendar of Events
Month Date(s)
April-May 30-2
May 15

Beef Cattle Short Course
Range Cattle REC Field Day

Gainesville, FL
Ona, FL

time 0-0_on 0 0- .-- q -% c.-- ,_-- -


Brachiaria Grasses For Peninsular Florida? ................................................ ...................... 2
Fertilize Pastures Early ................................................................................................................ 2
Fall and winter m management affects spring green-up in grass pastures ................................ 3
Effects of P Fertilizer, Lime, and Gypsum Application on Stargass Yield and Quality and
W after Quality........................................................................................................................... 3
Forage production from silvopastures in south Florida.................................. ........................ 4
Declining Herd Trend Continues ........................................................................................... 6
The Cost of Big Cows............................................................................................................... 6

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Brachiaria Grasses For Peninsular

To provide the best forage grasses
for commercial producers there is a
continued need for screening and testing
new forage germplasm and to develop
management practices under grazing. A
study was established using six tropical
grasses from Mexico consisting of four
Brachiarias, and two Andropogon's,
comparing them with Florona stargrass and
Pensacola bahiagrass. The Brachiarias
consisted of Insurgente, Abundance, B.
dictyoneura, and Chetumal. The
Andropogon cultivars were Llanero and Tun
tun. The year following establishment,
grasses were grazed at 2, 4, 5 and 7 wk
frequencies. Grasses were fertilized in the
spring of 2000 with 50-30-60 lb/A N-P205-
K20 + 1.5 lb/A Cu, Zn, Fe, Mn (sulfate
form), 0.15 lb/A B and 6.0 lb/A S. A total
of 150 lb/A N was applied annually in a split
application. Harvesting all grasses at a 2-wk
frequency averaged lowest yield (2.0 t/A)
and highest nutritive value (Crude protein
[CP] 20% and 68% digestibility), whereas at
a 7-wk frequency grasses produced highest
yield (5.0 t/A) and lowest nutritive value
(14% CP and 59% digestibility). Generally
a harvest frequency of 4 to 5 wk and grazing
frequency of 4 wk is recommended for
tropical grasses. In this study grasses
producing the highest total yield when
harvested at a 5-wk frequency were Florona
stargrass (4.8 t/A), Brachiaria Abundance
(4.3 t/A) and B. Insurgente (4.1 t/A).
Pensacola bahiagrass yielded 1.9 t/A when
harvested at the same frequency.
Forage nutritive value of the three
highest producing grasses was B. Insurgente
17% CP and 66% digestibility, B.
Abundance 17% CP and 68% digestibility
and Florona stargrass 22% CP and 60%
digestibility. Pensacola bahiagrass also

harvested at 5 wk averaged 20% CP and
59% digestibility.
Brachiaria Insurgente and
Abundance are excellent yielding and very
leafy bunch grasses with little or no winter
production. They have good CP
concentration and excellent digestibility. In
fact digestibility will run 6 to 8 percentage
units above Florona stargrass. The problem
with Brachiarias at Ona was cold tolerance.
The temperature during the fall of 2000 and
spring of 2001 dropped below 320F 11 times
with a one time extreme low of 190F. This
temperature regime killed 100% of the
Brachiaria study. One commercial producer
west of Okeechobee has been growing two
Bracharia cultivars for at least 3 yr with no
persistence problems. It appears that
Bracharia may be a viable alternative for
warmerwarmer areas of south Florida.

Fertilize Pastures Early

For ranchers who intend to fertilize
pastures this year now is the time to start
planning. What should you fertilize, and
when and how much should be applied?
In deciding what to fertilize, priority
should be given to fertilizing the better
quality forages such as hemarthria,
pangolagrass, and stargrass. Priority should
be given to fertilizing pastures that will be
grazed by younger cattle, especially first-
calf heifers.
Of course, bahiagrass is the major
pasture forage in Florida. The South Florida
Beef/Forage Extension Agents conducted an
excellent field study on 9 ranches in south
Florida to measure the benefits of different
fertilizer applications. They found that
bahiagrass showed a good response to
nitrogen fertilization, but little response to
phosphorus and potassium. The most
economical fertilizer application was to

spread 60 pounds of nitrogen per acre in
When nitrogen was applied in March
there was a very good response in
bahiagrass yield in April and May, and this
response continued through the summer
months. Nitrogen application also
significantly increased the crude protein
content of bahiagrass in the April and May
It is important to obtain as much
growth of good quality forage as early in the
spring as possible. Brood cows are just
coming out of the winter period, during
which they usually lose weight and body
condition, and are on the thin side. They are
often nursing calves and being exposed to
bulls for rebreeding. Thus, brood cows are
at a point in their production cycle with the
greatest demand for good nutrition.
If you are going to fertilize
bahiagrass, strong consideration should be
given to the South Florida Beef/Forage
Agents recommendation that 60 pound of
nitrogen per acre be applied in February or

Fall and winter management affects
spring green-up in grass pastures

Although temperatures under a
heavy canopy are slightly warmer than
temperatures of exposed grass crowns, a
large grass canopy at the onset of winter
does not lessen the chance of stand loss by
freezing. When typical frost occurs (as
distinct from freezing), a large canopy
hinders spring green-up compared to
pastures that do not carry a bulk of grass
into the spring. Nitrogen fertilization, if
applied too late in the fall, decreases frost
tolerance because it results in a flush of
tender growth. Plants that are rapidly
growing can not be frost hardened. In
addition, N fertilizer results in a large

canopy that shades new replacement growth
if it is not removed in late winter. What
frequently happens is that the canopy is
killed by frost and cattle do not consume it.
There is less green forage in the spring
compared to pastures with little cover. Frost-
sensitive grasses like bermudagrasses,
digitgrasses, rhodesgrass, and atra paspalum
are more prone to this problem than
limpograss or bahiagrass. It is best to
remove cover by cutting hay and grazing fall
regrowth or burning in late winter. In areas
where frost is common, the practice of
stockpiling forage for winter grazing should
be limited to grasses like limpograss.

In temperate regions, many lost
stands can be attributed to low K-
fertilization. Potassium increases the ability
of forages to survive freezing. I am not
aware of any K fertilizer research on
survival of tropical grasses in regions of the
sub-tropics where frost is common. On
bahiagrass in central and south Florida, this
is not an important issue. On hay fields
where K is removed with the harvested crop,
it is important to use narrow N:K fertilizers
to maintain summer production. This may
also guard the stand against loss by freezing.

Effects of P Fertilizer, Lime, and
Gypsum Application on Stargass
Yield and Quality and Water

Phosphorus (P) is a primary cause of
algae blooms and depletion of oxygen in
fresh water lakes in south-central Florida.
Research has shown that P fertilizer
application to bahiagrass pasture could be
eliminated without any adverse effect on
forage yield and quality. At the same time,
P levels in surface water runoff were
reduced by 33 to 60% as P fertilizer rates
were decreased from 100 to 25 lb P205/A.

Those studies led UF/IFAS to adopt a zero P
recommendation in 1998 for bahiagrass
pastures grazed in Florida south of Orlando.
The recommended P rate for other
improved pasture grasses such as stargrass
still range from zero to 40 lb P205/A for
high and low P soils, respectively. Studies
by Drs. Rechcigl and Bottcher,
demonstrated that fertilization of improved
pastures even at the optimum P
recommended rates caused a significant
increase in P levels of surface water runoff.
Hence, it became necessary to evaluate the
capacity of soil amendments for tying up
fertilizer-derived P on other improved
Field studies were conducted from
1999 to 2002 at Williamson Cattle Company
in Okeechobee to: 1) re-evaluate the
existing UF/IFAS recommended P fertilizer
rates for stargrass, and 2) study the
effectiveness of limestone and gypsum for
improving the retention capacity of soils for
applied P on stargrass pastures. Treatments
were 0, 25, 50, and 100 lb P205/A from
triple super phosphate applied to 50 ft x 100
ft stargrass pasture plots every year.
Treatments were replicated four times. The
amendments were calcium carbonate
(CaCO3) and mined gypsum (CaSO4.2H20)
applications based on 100% CaCO3 at 0, 1
and 2 T/A annually to plots that received
100 lb P205/A. All plots, including the
untreated plots (control), received one
uniform application of 80 lb K20/A from
KC1 and two equal applications of 80 lb N/A
as ammonium nitrate, annually. Forage was
harvested every 30-35 days in 1999-2001 for
dry matter yield, crude protein content,
organic matter digestibility and tissue
mineral content. Soil was sampled at 6 inch
intervals down to the hardpan every 6
months and analyzed for total P. Rainfall,
surface runoff volume, and depth of water
table were measured throughout each year.
Water samples from surface runoff and from

shallow PVC wells installed to 2 ft and 4 ft
depths inside plots were collected for water
quality analysis.
Phosphorus fertilizer or soil
amendments did not increase stargrass
forage yield, crude protein or digestibility
throughout the 3 years. Although applied P
improved forage tissue P level, most cattle
producers routinely feed a mineral mix to
provide adequate P. Increased P application
caused a significant buildup of P in the top,
middle, and hardpan soil horizons, increased
soluble P concentrations in shallow and deep
wells by 400% and 1500%, respectively,
increased P in surface runoff by 50%, and
raised the potential for non-point source of P
pollution. Gypsum was effective in
eliminating P leachate from applied P into
deep wells but was not beneficial for
reducing P in surface runoff. Although
promising in reducing total P in surface
runoff, the long-term benefit of Ca-lime was
not clear.
This study supports multi-county
fertilizer trials to provide strong evidence
that current IFAS P-fertilizer
recommendations for grazed improved
grasses of up to 40 lb P205 in south Florida
could be reduced at tremendous savings to
ranchers and protect the environment from P
pollution. Soil amendments per se do not
provide that kind of long-term protection.

Forage Production from
Silvopastures in South Florida

In silvopasture, trees are planted in
grazed pastures, and the components are
managed together for multiple products -
timber, forage and livestock. Our studies
have shown that profitable timber volume
and sales are possible from pine-bahiagrass
silvopasture. By integrating beef and forest
production systems, land use is optimized.
Therefore, pine-pasture silvopasture is

appealing to both cattle producers and forest
owners who are looking for efficient and
more profitable production and management
systems. Because of many economical and
environmental benefits of silvopasture, it has
attracted significant interest. However, not
all benefits are realizable in every
silvopasture. For the average producer in
south Florida, the primary concern may be
how trees in silvopasture will impact
grazeable acreage and forage production
since these are limiting factors in beef
The south Florida pine-bahiagrass
silvopasture established in 1991 at Ona,
presents an opportunity to determine
potential benefits of the system in south
Florida. Bare-rooted south Florida slash
pines were planted in a 40-acre Pensacola
bahiagrass pasture. We planted 450
trees/acre in double rows, 8' between rows
and 4' between trees. The double rows were
40' apart, which permitted sunlight needed
to maintain the grass and provide grazing.
After 14 months of deferment, 50 to 60 cow-
calf pairs have grazed the silvopasture every
year since March 1993, averaging 76%
weaning rate with calves averaging 450 lb at
230 days of age. By March 2002, 11 years
after grazing, pines averaged 28' tall, and
there were 200 trees/acre (44% survival).
The cattle have impacted the trees more than
the trees have affected cattle. It is, however,
from this age that yield reductions of the
pasture are expected to begin. Thus, we
conducted an experiment to estimate forage
yields of bahiagrass in the silvopasture and
compare them with grass yield in open
We selected seven 32' x 96' blocks
at different locations in the silvopasture that
had uniform stands of trees, approximating
the surviving stand density of 200 trees/acre.
Each block had two double-tree-rows with
one 40' alley between them, and a 20' half-
alley at each side. Between April and

September 2002, exclusion cages were used
to determine grass yields by sampling every
42 days from the center of the alleys, near
the tree rows, between the double rows, and
outside of the tree areas to estimate yield of
an open pasture. The pasture was fertilized
with 50 lb N/acre in March every year since
1991, and an additional 4 and 41 lb/acre of P
and K, respectively, since 1998.
The highest seasonal grass DM yield
of 4.6 ton/acre was obtained at the center of
the alleys, with 3.3 ton/acre from adjacent to
tree rows, 1.4 ton/acre from between the
double rows. Grass yield from the center of
the alleys was about 44% greater than yield
obtained from the open areas (3.2 ton/acre).
When we calculated the total forage
production of the silvopasture from the
proportionate contributions from the center,
near tree row, and between tree rows, we got
3.7 ton/acre, which is 15% greater than yield
obtained from the open pasture. These
figures suggest beneficial pine-grass
interactions. All the pine needles fell
between and near the tree rows. We found
that the higher the amount of pine needle
litter, the lower the grass yields.
We are continuing this study to
obtain more information. Pertinent questions
are: Will the apparent positive effect of trees
on the pasture continue? What would be the
benefit of thinning out poor quality trees
(presently pulpwood sizes) on forage and
beef production? To obtain answers to these
questions, we have thinned pines on 20 acres
to 125 trees/acre, while retaining the tree
density on the other 20 acres. We will graze
both sections, and another 20 acre open
pasture, and in the next 3 eight years, we
will compare calf production and timber
values, and the economics of the system on
thinned and not thinned stands with the open

January 2003 Inventory; Declining
Herd Trend Continues

The National Agricultural Statistics
Service (NASS) branch of the USDA
released its latest cattle inventory numbers
and estimates on January 31. They show
that cattle inventories have continued the
downward trend which began in 1996. That
trend puts the cattle industry into the 14th
year of the cattle cycle, and there are no
clear indications of a herd expansion.
Florida's cattle inventory numbers
were in line with the national trend. Overall
2003 Florida cattle and calves inventory is
estimated to be down one percent to 1.75
million head from 1.78 million head in
2002. All cows that had calved are
estimated to be down 10,000 head to 1.1
million. Beef cows that had calved totaled
953,000, down one percent from 2002, and
milk cows that had calved totaled 147,000,
down three percent from 2002. Calf crop
numbers show a one percent decline from
940,000 head in 2001 to 930,000 head in
Heifer hold-backs are a key indicator
of potential herd expansion and the
inventory numbers show little evidence of
such a trend beginning. Beef cow
replacements in Florida are down from
140,000 to 130,000 head. Milk cow
replacements held steady at 40,000 head.
This is consistent with the national figures
and may be an indication that the current
cycle may last into 2004 and beyond which
can potentially translate to continued strong
cattle prices through 2006. The already tight
fed beef supplies will only get tighter as a
result of these shrinking numbers further
helping maintain prices in the current
economic conditions.
The number of cattle operations in
Florida fell slightly during 2001-2002.
There were 19,000 cattle operations in
Florida in 2002 down 500 operations from

2001. Beef cow operations were steady at
16,500 operations. Milk cow operations
declined two percent from 510 operations in
2001 to 500 operations in 2002.
An analysis of size and inventory
distribution indicates that operations with
over 500 head, roughly 3.4 percent of the
operations, account for 57 percent of the
Florida cattle inventory. In the dairy
industry, operations over 500 head, 20
percent of the total dairy operations, account
for 83 percent of the dairy cows in Florida.
In contrast, similar sized Florida beef cow
operations, 1.7 percent of the total beef
operations, account for 45 percent of the
state's beef inventory.

The Cost of Big Cows

The importance of cow efficiency
has been largely overlooked by the cow-calf
industry. Although our production systems
have made important advances in the
production of large calves with heavy
weaning weights, the cost for maintaining
the associated cowherd is often ignored.
Cow efficiency is something that we all
understand, but often do not consider in our
day-to-day management decisions. When
discussing cow traits we routinely use terms
like "easy-fleshing" and "easy-keeping".
These characteristics are related to cow
efficiency. In Florida, pasture forage
availability is limiting during the early
spring at a time when most of our cows are
in mid-lactation. This is an excellent
opportunity to see cow efficiency at work on
your operation. Within the herd we can
identify that group of cows that are able to
maintain body condition beyond the herd
average even during harsh grazing
conditions. Although these cows are
maintaining moderate condition, their calves
are usually as large as the herd's average.
These cows have improved efficiency.

Considering that over 60% of the annual
costs for a producing a calf are attributed to
nutrition, our ability to identify efficiency
traits and incorporate them into the cowherd
is critical.
An average body size for mature
Florida cows might run between 1000 and
1200 lb. It would be common to find these
cows in average production systems across
the state. Have you ever considered the
costs associated with maintaining this
difference in body size? On average, a
mature cow will consume about 2.25% of
her body weight daily throughout the year.
A typical diet must average about 50% TDN
annually to maintain a mature cow. Using
these figures, the 1200 lb cow will require
about 820 lb of additional TDN per year
compared to the 1000 lb cow. This added
requirement will be most pronounced during
the early spring when supplemental nutrition
is critical to account for shortages in pasture
forage. An average cost for supplemental
TDN is about $0.08 per pound; therefore,
the 1200 lb cow may require an additional
$65 in supplemental feed compared to the

1000 lb cow. Using a weaned calf price of
$0.90 per pound, the 1200 lb cow will need
to wean a calf that is 72 lb heavier (on-
average) than the 1000 lb cow just to offset
her additional supplement costs. Usually,
there are only minor differences in calf
weaning weight between cows of similar
breed that differ in size by only 200 lb.
The example above assumes a
constant efficiency between both cow types.
Our ability to identify cow efficiency traits
and perpetuate them in the herd will likely
be the new frontier for improving beef cow-
calf profitability and sustainability.

Adjei, Martin B.
Anton, T. E., Ed.
Arthington, John D.
Ezenwa, Ike V.
Kalmbacher, Rob S.
Mislevy, Paul
Pate, Findlay M.

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