Institute of Food and Agricultural Sciences (IFAS)
Department of Animal Sciences
Quarterly Newsletter Vol. 8 No. 2 Spring 2008
IT'S SPRING CLEANING TIME AGAIN! # 13
David R. Bray
Now is the time to prepare for the long hot summer. I'm
going to repeat this thing until you do these tasks
1. Clean out high organic matter dirt (MUD) in lots and add
new dirt, especially in calving areas.
2. Clean out cooling ponds pump out the water, and clean
out the sludge and spread it someplace where the cows do
not have access to it.
3. Let ponds sit dry for the sun to work on the bacteria.
Mycoplasma and other nasty stuff live in ponds. You
must clean them out at least once a year if you
continuously add water to the pond. If you DO NOT
continuously add water, you need to sample the ponds for
Mycoplasma and pump and clean out the ponds once or
twice during the summer.
4. Clean your fans. Dirty fan shields can reduce fan
efficiency by 50%. You can purchase and install twice as
many fans if you wish not to clean them. If cows are in
the barn or holding area, run fans 24 hours a day. This not
only moves air to cool cows, it also helps to remove
moisture and dry the place out.
5. Make sure your sprinklers, foggers, etc, work. It was a
cold winter; many pipes froze and/or broke, and dirty
nozzles don't add much water. Check timers for the
proper time for adding water. Constant water is not as
efficient as intermittent sprinkling and saves water. Set
your sprinkler thermostat at 75 degrees F or lower during
the hot season. Sprinklers need to run at night because
cows get hotter at night than daytime on those hot nights.
To repeat the above message, you need timers to control
sprinklers or you will waste great volumes of water.
6. Clean and rebuild your pulsators. Wash out and change
the filters on your vacuum controller (unless you have a
variable speed drive). Make sure all ATO's work.
7. Replace all milk hoses, wash hoses, pulsator hoses and
jetter cup holders. Replace all rubber hoses that may be in
the milk house that may add water to the pipeline and /or
bulk tank wash. These hoses harbor Pseudomonas and
Coliforms and can raise your bacteria count. If rubber
hoses are used to wash udders, change them also.
8. Replace all of your floor mounted cow wash sprinkler
nozzles once a year. Spring is a good time to do this.
They not only clean cows, they cool cows also.
9. Clean your condenser fins on your milk coolers. Dirty
fans cut down cooling and efficiency and you get warmer
milk at higher electric costs.
10. Mow and spray careless weeds in pastures.
11. Cull your chronic mastitis cows now. It will lower your
cell count and your help is sick of treating them.
12. Clean out the back half of your free stalls at least 10-12"
deep and add new sand.
13. Keep a smile on your face. People will wonder what you
are up to.
To learn more about spring cleaning, contact Dave Bray
at drbrayvufl.edu or call (352) 392-5594.
DAIRY BREEDING SURVEY SUMMARY
A Breeding Methods Survey was given to all dairy
producers attending the December 11, 2007 SMI Board
Meeting. Many thanks to the producers who returned their
surveys. Following is a summary of information returned:
* 18 herds from Florida responded; one herd each from the
Panhandle and Central FL; 8 herds each from North and
o Average # cows/herd = 2017 (range 350 to 8700
from 18 herds).
o Average # heifers/herd (raised by owner or
someone else for owner) = 1597 (range 175 to
8000 from 12 herds).
o Of the herds reporting both cow and heifer
numbers, there was an average of 66% number
of heifers to number of cows.
* Of the 18 herds from Florida who responded, 15 were
breeding by AI currently.
o 11 herds bred year around.
o Most of those breeding seasonally avoided
calving during the summer months.
* 7 herds bred their cows only during natural heats. The rest
used some form of synchronization.
* 10 herds reported winter and summer cow conception
rates. They averaged 32.4% in the winter (range 24 to
45%); 16.5 % in the summer (range <10 to 25%).
* 3 herds tried gender-biased semen on cows. Reported
o Conception rate of 35% in winter with a 65%
female calf crop from Accelerated semen.
o 2 herds used Select sexed (90% female crop)
semen; 1 reported 15-20% conception rate;
neither had calves born yet from this gender-
* 13 herds reported breeding heifers by AI; 6 have used
gender-biased semen. 6 herds reported breeding heifers
only on natural heat; 4 synchronized; 1 herd used both
* Conception rates of heifers using regular semen averaged
* 4 herds reported conception rates for both conventional
and gender-biased semen:
(Select) 70% 40%
(Select) 60% 45%
(Select) 85% 70%
(Accelerated) 65% 60%
* 3 herds reported calf crop sex percentages from gender-
biased semen of: 90 and 95% heifers using Select semen;
65% heifers using Accelerated semen.
Observations: improving the overall conception rate in
Florida would be of major benefit to all dairy producers for
providing adequate herd replacements. AI representatives
report many producers are currently buying gender-biased
semen for more female offspring. The limited data above
would indicate the calves resulting from gender-biased semen
are coming in the female to male ratios the bull studs are
advertising. Lower conception rates (and therefore greater
time to calving), higher priced semen, and often lower genetic
value of the bulls available with gender-biased semen, are all
factors which need to be considered in the equation for using
Mary Sowerby is a UF Regional Dairy Extension
Educator based in Live Oak, FL. Reach her by email,
meso@,ufl.edu, or call (386) 362-2771.
FLORIDA STUDENTS COMPETE AT SEVENTH
NORTH AMERICAN INTERCOLLEGIATE DAIRY
Albert De Vries
Four University of Florida students interested in dairy
science participated in the 7t North American Intercollegiate
Dairy Challenge (NAIDC), held April 4-5, in the Madison,
Wisconsin area. Hosted by the University of Wisconsin-
Madison, the event attracted a record number of 32 teams (128
students) from the United States and Canada, challenging
them to put their textbook and practical knowledge to the
ultimate test analyzing dairies. The contest started with a
walk-through at the dairies, followed by the opportunity to ask
questions of the owners and analyze farm-specific data.
Student teams used this information to develop management
recommendations, and then presented their management
recommendations to the herd owners and a panel of five dairy
industry judges. An awards banquet completed the two-day
The Florida team, consisting of Diane Tearney, Hamilton
Bishop, Adam Lichti and Judd Sims, received a Gold award
for their efforts. Earlier, the team had practiced at DPS-
The Florida participants at the 7th North American
Intercollegiate Dairy ( lll,,. i.- in Madison, WI. From left,
Judd Sims, Diane Tearney, Hamilton Bishop, Adam Lichti,
andAlbert De Vries (coach)
Supported financially through generous donations by
industry and coordinated by a volunteer board of directors, the
first NAIDC was held in April 2002. In 2009, the NAIDC will
be held March 29-30, in Syracuse, NY. The third Southern
Regional Dairy Challenge is planned for November 20-22,
2008 in Statesville, NC. For more information about NAIDC,
log on to www.dairvchallenge.org or contact Albert De Vries,
devriesaiufl.edu, (352) 505-8081.
MR. SANDMAN (RECYCLED)
David R. Bray
In my quest to improve my knowledge of the Dairy
Industry, I went to the Sand Solution Conference in Wisconsin
the week before Thanksgiving. This trip might have been
more pleasant in the summer.
I was interested in what happens in the area of recycled
sand and mastitis, and different ways of sand separation. Sand
was separated from the manure by big screws on the dairy we
visited and many neat innovations are being used to clean sand
and the water used to separate the sand from the manure. This
equipment looks expensive and has to be protected from
freezing. Our long flush lanes make sand separating much
What I did learn was, you need coarse sand to separate
sand from manure with big screws. They prefer concrete sand,
ASTM C33, because it has a large particle size which is
needed for the big screws to pick up the sand out of the water.
This is also the choice for bedding because smaller sand
particles pack tighter together and don't drain well and
increase the bacterial levels of the bedding. The reason for the
coarse sand being preferred for mastitis reduction is coarse
sand does not pack like fine sand. Our Florida sand is very
fine and packs and doesn't drain. Many people have done
bacteria loads in sand bedding, including us, and the results
are all about the same.
Why do we bed with sand?
1. Its inorganic and does not support bacterial growth.
2. Cool in the summer, wicks moisture away from the cows
3. Provides a soft place to lay.
4. Provides a secure surface for a cow to get up and down.
If sand is inorganic why does it have bacteria in it?
1. New sand comes from the ground. There are always
bacteria in nature.
2. The cow is organic and has bacteria on her skin.
Klebsiella, coliforms, streps and many other bacteria live
in the gut and get on the body and are transferred to the
3. Leaking milk may add bacteria but sure supports bacterial
4. Recycled sand is washed with water either flush water or
other water and it should have less than 1 % organic
matter in it. Klebsiella and all these bad boys are in
recycled flush water, that get in the beds due to foot
traffic if cows are in the barn during flushing.
What levels of bacterial concentration will increase a
cow's chances of getting mastitis?
1. Most people are worried about the environmental
bacteria, with the coliforms being the biggest worry.
Cows die from the Klebsiella, E. Coil's no matter what
type of milking procedures you try. The streps seem to be
controlled with a good pre milking sanitation.
2. The old rule of thumb has been that with a coliform count
be under 1,000,000 CFUs per ml you should be safe. Our
experience has been that we have seen big problems in
that range. Wisconsin workers suggest this be 100,000
CFUs per ml.
3. Obviously bacteria multiply faster in warm temperatures.
That's why mastitis is higher in the summer or most of
the year in the Southeastern US.
4. Recycled sand will have more organic matter (1%) than
fresh sand so it will have faster bacterial growth than new
5. For these reasons, in most cases re-bedding every 4 days
or twice a week and leveling and fluffing stalls every
milking or at least once a day will keep you in the safe
When should I remove all material in the back half of the
1. It should be removed when coliform counts hit 100,000
CFUs per ml, but in the Southeast at least twice a year (in
April and October).
2. If you have real fine sand and it packs quicker, you may
have to do it sooner.
3. I use a flat sided soil sampler that the side hinges up and
you can see the wetness, color and texture for about 8"
down. You can compare this to the front of stall. It's
pretty obvious, the smell will tell you.
4. A clam shell post-hole digger or a shovel will also do the
Overlooking the obvious: In all the years I have taken
sand samples I have never written down how to take sand
samples. Thanks to Dr. Nigel Cook from the UW Veterinary
School for putting this in writing.
Methodology for collection of Bedding Culture Samples:
1. Wear latex gloves.
2. Sample the rear of approximately 10 stalls per pen -
grabbing grossly uncontaminated bedding from the
location of the udder.
3. Mix in a gallon Ziploc bag, sub-sample and freeze
4. Always compare used sand with fresh sand samples for a
5. Ship to the lab on ice.
DHI PEAK MILK
Daniel W. Webb and John Clay
Peak milk production is the highest recorded test day milk
production in a cow's first 150 days of the lactation. In
PCDART, a cow must be in milk 100 days or more to have a
value for peak milk. Early lactation cows have a peak value of
0 until the first test-day after 100 days. By waiting 100 days,
only one value will be identified as peak milk. All test days
from 7 to 150 days in milk will be used to determine peak.
Peak milk production is an indication of how well the cow
responded to feeding and management during the dry period,
calving and early lactation periods. For first lactation cows, it
provides excellent insight into the heifer development program
and how well heifers have adjusted to the milking herd.
Transition cow management has become a critical challenge
for today's dairies. Peak milk and when it occurs affords a
realistic indicator of how well the manager handles these
cows. Although peak milk production usually occurs prior to
day 100, there is a specific optimum day-in-milk when peak
milk production should occur for most cows. Since most herds
do not record milk weights every day, it is unlikely that peak
milk is recorded on the day that milk production actually is the
highest. However, by evaluating records for groups of cows,
proper analysis is still possible.
DRMS uses standard lactation curves to identify when a
cow should have peaked. More than 1 million lactation
records were used in research to determine the standard days-
in milk for peak milk. The standard curves were established
* Six seasons: Jan-Feb, Mar-Apr, May-Jun, Jul-Aug, Sep-
Oct and Nov-Dec.
* Three ages: first lactation, second lactation and third+
* Two breed groups: Ayrshire-Brown Swiss-Holstein and
This research purposely used production records from
cows not receiving rBST. Examples of standard days-in-milk
at peak milk for first lactation Holstein cows are:
* January or February calving month = 70 days
* May or June calving month =61 days
* September or October calving month = 85 days
The above list indicates that first lactation cows that calve
in May or June are expected to peak 24 days sooner than first
lactation cows that calve in September or October. This earlier
peak milk evidently results from the seasonal effects of heat
and humidity stress on cows that calve at the beginning of
PCDART Database Items
PCDART provides three database items to evaluate peak
* 107 = Peak milk
* 147 = Days in milk at recorded peak
* 148 = Deviation in days in milk at peak (observed minus
Please note that the standard curves were only used to
determine the standard days-in-milk at peak. All other values
are dependent on the cow's recorded information. Also it
should be pointed out that herds with irregular or long test
intervals will have less reliable peak milk values.
PCDART examples below illustrate a beginning analysis
of peak milk for three herds with averages for three groupings
(lactation 1, lactation 2 and lactations 3+). Peak milk in the
first two herds occurred much later than expected 17 and 26
days later, respectively. However, it seems that the third+
lactation cows in Herd 1 peaked sooner, relative to the first
and second lactation cows. An analysis of the individual cow
records may provide clues to the reasons. In both herds, the
first lactation cows peak later than expected, relative to the
older cows. In Herd 3, days-in-milk at peak occurred closer to
expected (+3 days). However, the second lactation cows
peaked earlier (-9 days) than expected.
002 PEAK MILK ANALYSIS FOR
T.D. Peak DIM Lact
Milk DIM Ob-St No.
86.6 93 +21 1
109.3 69 +15 2
122.3 66 +13 3+
002 PEAK MILK ANALYSIS FOR HERD 2
002 PEAK MILK ANALYSIS FOR HERD 3
T.D. Peak DIM Lact
Milk DIM Ob-St No.
69.8 74 +3 1
79.5 46 -9 2
84.7 60 +9 3+
79.0 60 +3 All
While these examples may be different in every herd, this
method can be useful to evaluating your herd.
John Clay is director at DRMS in Raleigh, NC. Contact
Dan Webb at (352) 392-5592, or dwwebb(@ufl.edu.
UPCOMING DAIRY MEETINGS
* The 45th Florida Dairy Production Conference is
scheduled for Tuesday April 29, 2008. Location will
again be the Hilton University of Florida Conference
Center in Gainesville, FL. Contact Albert De Vries,
devrieshiufl.edu, (352) 392-5594, for more information.
* New this year is an Open House at the Dairy Research
Center in Alachua on Wednesday morning April 30,
2008. Come and see what is going on at the DRU.
Contact Albert De Vries, devrieskiufl.edu, (352) 392-
5594, for more information.
* UF/UGA Corn Silage and Forage Field Day is planned
for Thursday May 29, 2008 at the Plant Science Research
and Education Unit, Citra, FL. Program: visit
www.animal.ufl.edu, click on Department Calendar. For
additional information contact Jerry Wasdin, (352) 392-
1120 or email@example.com.
* The annual Florida Dairy Business Conference is
planned for Monday September 8, 2008. Location will
be the Marion County Extension Office in Ocala. For
more information, contact Russ Giesy, giesvyrufl.edu,
(352) 793-2728 (office).
For registration information, agendas and other meeting
details, visit the Florida Dairy Extension site at
http://dairv.ifas.ufl.edu or contact Albert De Vries,
devries(iufl.edu, (352) 505-8081.
Dairy Update is published quarterly by the Department of Animal Sciences, University of Florida, as an educational and informational service. Please address any
questions or comments to Albert De Vries, Editor, Dairy Update, PO Box 110910, Gainesville, FL 32611-0910. Phone: (352) 392-5594. E-mail: devries(Aufl.edu.
Past issues are posted on the UF/IFAS Florida Dairy Extension website at http://dairv.ifas.ufl.edu. This issue was published on April 14, 2008.