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It's Time
for Spring Vaccinations •
Replacement Heifers - A
Strategy for Success •
Recording of Recent Extension
Programs Available Online
It's Time for Spring Vaccinations
Jeremy Powell
With spring breeding season approaching, now is the time to be
thinking about spring vaccinations. The goal of vaccinating the herd
is to protect the cows against reproductive diseases prior to the
breeding season and also to provide protection to the spring-born
calves against potential disease agents. Obviously, no vaccination
program is 100% effective, but the objective is to maintain a high
level of herd immunity to minimize disease outbreak and improve
profitability for the operation. Vaccination programs should always
be customized for your operation, and a number of different vaccines
and vaccine combinations are available for cattle. Therefore, it is
important to work with a veterinarian who is familiar with your beef
cattle operation when making selection decisions.
When determining which type of vaccine to use, keep in mind that
there are differences between a modified-live vaccine (MLV) and a
killed vaccine. Advantages of MLV products include a fast immune
response and long duration of immunity. The downside of MLV vaccines
is that some are not labeled for use in pregnant cows or in calves
that are nursing pregnant cows. However, there now are a few MLV
vaccines on the market that can be used in pregnant cows as long you
closely follow the manufacturer's recommendations for these
products.
Killed vaccines contain only killed microbes or microbial parts.
They are generally considered to be safer and more stable than the
MLV products but produce shorter-lived immunity. When used for the
first time in an animal, most killed vaccines require an initial
dose followed by a booster dose two to six weeks later.
Although herd health needs may vary among operations, there are a
few standard vaccines that should be included for most herds. For
cows and bulls:
- 4- or 5-way viral vaccine (IBR, BVD, PI-3, BRSV)
- Leptospirosis
- Vibriosis
- 7-way clostridial (Blackleg)
These vaccines will protect against diseases that can lead to a
loss of efficiency and profitability in a cowherd.Vaccines
recommended for calves include:
- 4- or 5-way viral vaccine (IBR, BVD, PI-3, BRSV)
- 7-way clostridial (Blackleg)
If vaccinating replacement heifers consider:
- Brucellosis (Bang's) vaccine between 4 and 12 months of age
- 4- or 5-way viral vaccine (IBR, BVD, PI-3, BRSV)
- Leptospirosis
- Vibriosis
- 7-way clostridial (Blackleg)
Some operations may give consideration to other vaccinations
based on the case history of diseases in the herd. If your herd has
encountered problems with pinkeye, calf scours or respiratory
pneumonia in the past, there are vaccines for these problems that
will help limit future outbreaks. Since vaccine needs vary from herd
to herd, it is important to visit with your veterinarian to get
input when selecting vaccines for your operation.
Several factors can occur that may cause a vaccine to result in
an inadequate immune response. Handling of vaccine is crucial and
special care should be taken. Improper storage can damage vaccines.
Vaccines should be kept at refrigerated temperatures between 35°F
and 45°F. Exposure to freezing temperatures or to temperatures that
exceed the recommended range could leave the vaccine ineffective. It
is important to protect vaccine while at the chute and during
transport to maintain ideal temperature. Also, the use of
disinfectants on needles or inside the barrel of pistol-grip
syringes can lead to inactivation of modified-live vaccines.
A general concern of some producers is whether or not the costs
of implementing a vaccine program are justified by disease
prevention. Avoiding a potential health disaster in your cattle
operation validates the cost. Keep in mind the old adage - "An once
of prevention is worth a pound of cure." In other words, the costs
of a disease outbreak will far exceed the price of disease
prevention.
Remember that a vaccination program alone shouldn't be considered
your complete herd health program. The vaccination program should be
viewed as an important part of an effective health management plan
that also includes proper nutrition, parasite control and a simple
biosecurity plan for your operation.
Find out more information about beef cattle herd health
management at your
county
Extension office.
Replacement Heifers - A Strategy for
Success
Brett Barham
Traditionally, many cattlemen have selected replacement heifers
based largely on which heifers look the best.While this selection
practice emphasizes genetics for growth and tends to pick heifers
from the earliest-calving cows, it may not result in sufficient
focus on genetics for expressed fertility, calving ease, optimum
levels of milk production, sensible maintenance requirements and
adequate longevity. Present-day genetic information affords
producers the ability to produce and select replacements with a
higher likelihood of success, as compared to traditional approaches.
What Makes a Successful Replacement Heifer?
What does a replacement heifer need to do in order to achieve
production success? Most producers would agree that successful
replacements:
- reach puberty and become pregnant early in the first
breeding season;
- calve unassisted each year;
- breed back early in the second breeding season as wet
two-year-olds, with high levels of sustained fertility
thereafter;
- have optimum milk and fleshing ability, so as to wean
profitable calves yet maintain sufficient body condition for
early annual rebreeding;
- have sensible maintenance requirements as a result of mature
size and milk production levels which are matched to available
feed resources;
- have sound teats, udders, feet and legs as well as calm
temperament and as much longevity as possible to minimize annual
replacement rates;
- represent genetics for optimum levels of growth, efficiency
and carcass merit for the purpose of producing profitable feeder
and fed cattle as well as replacements; and
- possess high salvage value so as to offset replacement
costs.
Given the demanding list of attributes required of replacement
heifers, it is useful to consider how genetic information might be
used to select for success. Opportunities to take advantage of
genetic information exist at three points of heifer production:
- When sires are selected to produce replacement heifers
- When heifers are selected from the pool of replacements
- When sires are selected to breed replacements
Selecting Sires to Produce Replacements
The better the pool of potential heifers from which to select,
the better the odds of selecting a productive group of replacements.
For commercial cattlemen, there are at least two keys to producing a
superior pool of replacements:
1) a well-designed crossbreeding program that generates maternal
heterosis and uses breeds well adapted to the production environment
and 2) use of EPDs to select sires with genetics for the combination
of items listed above.
Choosing which breeds to use in crossbreeding starts with an
evaluation of your present cowherd and feed resources, as well as a
determination of the targeted end-product market. Selecting breeds
from which to produce replacements should also go beyond evaluation
of only puberty and level of milk production. Selection should
include consideration of breed comparison data related to maternal
calving ease, calf vigor and survivability, cow maintenance energy
requirements, mature cow size, optimum milk production, convenience
traits such as teat and udder soundness, longevity and traits
contributing to life cycle production efficiency.
Selecting Replacements Heifers
In addition to known pedigree and performance information from
the sires and dams of replacements, performance data can be
collected from yearling-age heifers when they are processed prior to
breeding as part of the herd health program. Collection of the
following information can help guide selection of heifers toward
genetics for early puberty, maternal calving ease and growth, as
well as moderate mature size and adequate fleshing ability.
Reproductive Tract Scores - The reproductive tract scoring
system estimates a heifer's pubertal status via rectal palpation of
the uterine horns and ovaries.Tract scores range from one to five,
with heifers scored as four and five believed to be cycling based on
the presence of a corpus luteum or large follicle on the ovaries and
good uterine tone. Heifers scored as three are thought to be on the
verge of cycling, while those scored as one and two have more
infantile, less developed reproductive tracts and are not yet
cycling. Research has indicated that heifers scored as three, four
or five generally have higher pregnancy rates and earlier conception
dates compared to heifers scored as one or two. In addition to
serving as a heifer selection tool, reproductive tract scores can be
used to determine if a group of heifers is sexually mature enough to
respond favorably to a synchronization and A.I. program. Palpation
of the reproductive tract can identify freemartins or heifers that
might already be pregnant prior to the start of the breeding season.
Many large animal vets can evaluate reproductive tracts of
replacement heifers.
Pelvic Measurements - Calving difficulty primarily occurs
among first-calf heifers as a result of "heavy" calf birth weight in
relation to the size of the dam's pelvic area.While birth weight is
unquestionably the key direct factor related to calving ease, pelvic
area appears to be the highest ranking maternal variable. Colorado
State University research has shown that as birth weight of calves
increases and pelvic area of replacement heifers decreases, the
incidence of assisted births also increases. Depending upon the
average pelvic size of the group, culling heifers with the smallest
pelvic areas (i.e., smallest 5 to 10 percent) has been shown to help
reduce the incidence of assisted births.
Yearling Weight, Hip Height and Condition Score - Weight,
height and condition information can be used to select heifers with
adequate early growth and fleshing ability but help avoid selecting
heifers that might be too big and hard fleshing later in life.
Avoiding heifers that are too extreme - either excessively big or
small - is expected to contribute to greater cowherd uniformity.
"The accuracy of replacement heifer selection can be improved by
combining these yearling data with knowledge of pedigree information
from sires and dams for appropriate levels of maternal traits (i.e.,
milk) and longevity, with incorporation of a visual evaluation of
soundness and doing ability."
Selecting Sires for Replacement Heifers
While the first test of a replacement heifer is becoming pregnant
early in the first breeding season, the next major hurdle is the
heifer's ability to give unassisted birth to a live, vigorous calf.
In addition to avoiding production and selection of heifers with
genetics for high birth weights themselves, selection of service
sires on the basis of their EPDs for low birth weight, high expected
calving ease and short gestation length is the most reliable way to
minimize calving problems.
Calving ease in first-calf heifers is also related to
reproductive performance during the second breeding season. Research
has demonstrated that heifers that do not require assistance at
calving tend to have higher pregnancy rates following the second
breeding season by 3 to 5 percent and are about a week earlier in
terms of day of second calving, as compared to heifers that require
assistance. This is most meaningful when you consider that the
number one reason cows are prematurely culled at young ages is
because of reproductive failure (open at the end of the breeding
season).
Implementation of an A.I. program and synchronization, whereby
sires can be reliably selected for calving ease in addition to
adequate performance in other traits, is the most sure-fire way to
genetically manage for a successful first calf from replacements.
Through the use of A.I., unique service sires can be used that not
only minimize calving difficulty but also pass on genetics for the
desired combination of maternal, growth and carcass merit.
Considerable risk can be managed through the use of synchronization
and A.I. in replacement heifers.
Summary
Successful replacement heifer selection begins with wise
selection of the sires from which heifers are produced. Once a
superior pool of replacements is developed, use of performance
information collected on yearling heifers, as well as information
known about the sires (or group of sires) and dams of heifers, can
be used in conjunction with visual evaluation to improve the odds of
selecting the most productive heifers. Finally, smart selection of
sires to breed to heifers can help ensure calving ease and
production of a profitable first calf from replacements. Through
planned crossbreeding and disciplined use of available genetic
information, heifers can be produced, selected and bred with more
confidence and less risk, as compared to traditional practices.
Source: Dr. Kent Anderson, North American Limousin
Foundation
Recording of Recent Extension Programs
Available Online
Brett Barham
Beef producers are busy people and may not find the time to
attend educational meetings that might provide some valuable
information for their operation. Sometimes a program of interest may
involve a several hundred mile trip and can be quite costly to
attend. The Extension Animal Science group has been recording many
of our programs so that producers who were unable to attend will be
able to get the information presented at a meeting. This allows you
to view the information presented at a later date and on your
schedule. Here are some recent programs that are available online:
I hope these videos are helpful to you and your operation. I
would appreciate hearing any feedback you might have on these online
videos - were they useful, did you have any technical problems, etc.
Call 501-671-2162 with any
feedback you might have.
Jeremy Powell, DVM Associate Professor - Veterinarian
Brett Barham, Ph.D. Assistant Professor - Breeding and Genetics
The information given herein is for educational purposes only.
Reference to commercial products or trade names is made with the
understanding that no discrimination is intended and no endorsement
by the Arkansas Cooperative Extension Service is implied.
Printed by the University of Arkansas Cooperative Extension
Service Printing Services.
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