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Dairy Heifer Health, Disease Control and Vaccinations
The future of the dairy herd is dependent on the production of superior heifers to replace culled lactating animals. Therefore,
it is imperative that the health status of the replacement animal is optimized to present a healthy first calf heifer to the
lactating herd. Studies have consistently demonstrated the detrimental effects of pneumonia in calves on age at first calving
and on milk production once these animals enter lactation. Calves with respiratory infections were twice as likely to leave the
herd, and age at first calving was delayed by 6 months when compared with calves that did not experience respiratory disease
or pneumonia. In another study, calves treated for scours were three times more likely to calve at 30 months of age or greater.
The areas of primary concern in maintaining the optimal health of the heifers include parasite control, coccidiosis, infectious
diseases like IBR, BVD, PI3 and BRSV, and other problems such as pink eye and foot rot. Mastitis control in pre-partum heifers is
also included in this list.
Health
Both parasite control and the feeding of growth promotants
improve feed efficiency and enhance growth. Regular deworming
and treatment programs for internal and external parasites are
essential to improve heifer performance. At the Virginia Tech dairy
facility, we use a strategic deworming protocol. This protocol not
only deworms the heifers, but decreases the parasite (worm) larva
population on the pasture. Heifers are first dewormed in early May,
using an ivermectin or eprinomectin product. This rids the heifers
of the initial parasite burden obtained during the early warm, moist
days of spring, when parasite loads are beginning to peak in cattle
and on the pastures. The second deworming occurs 5 weeks later
dependent on whether the product is a pour-on, injectable or bolus.
The reason for this second 5-week injection is two-fold. First, the
ivermectin has residual internal parasite killing activity for 2 weeks.
Therefore, any parasites developing in the digestive tract during this
time period of 2 weeks will be eliminated. After this 2-week period,
many parasite larva ingested on the grass or pasture contamination
will develop into adults. This development period is approximately
3 weeks (larva to adult parasite). The second injection, 5 weeks later
in mid June will eliminate or kill these adults. By keeping the adult
infection (which produce larva for the pasture) to a minimum within
the digestive tract of the calf, we maintain minimal parasite burdens
on the pasture as well. These two injections give adequate protection
during the peak period of parasite contamination.
When using the eprinomectin pour-on product the second
deworming should be administered at 5 weeks, as well. There is some
data to support a residual activity of 4 weeks with the eprinomectrin
product; however, to date, this is not supported with adequate
information.
Typically by early July, pasture parasite loads will begin to decrease
due to hot weather and decreased moisture. If good parasite
management has been implemented, parasite burdens on the
pasture will be negligible. Producers should be cautioned against
introducing heifers that have not been dewormed, as they can be
a source of parasite contamination for the pasture and the original
dewormed heifers. A third deworming of a single dose of either
product may be beneficial in late October. This would eliminate
internal and external parasites (grubs and lice) obtained during the
summer and decrease the parasite load prior to winter feeding. Also,
if the summer season has been mild and moisture has been high,
parasites will survive in higher numbers on the pasture, causing a
higher heifer parasite load.
Coccidia control measures should be started in baby calves at 5 to
10 days of age and continue until 30 days prior to calving. These
products are found in some milk replacers as well as a feed additive
in concentrate. Medicated feeds may improve performance and can
aid in the prevention of coccidiosis, when calves are fed a specific
coccidiostat like decoquinate, Rumensin®, or Bovatec®. Ionophores,
such as Bovatec® or Rumensin®, are effective as an aid in reducing
coccidiosis, but have the added benefit of improving feed efficiency.
However, ionophores are not effective as a treatment against
coccidia. If calves have been diagnosed with coccidiosis, they should
be treated with Corid® (amprolium) or sulfonamides (sulfa) and then
fed one of the ionophores for prevention. Supplementation costs
pennies per heifer per day, which is more than offset by decreasing
the amount of grain required per pound of gain, or supporting
adequate growth with lower quality forage for older heifers. The use
of ionophores in confinement-reared heifers or those fed excessive
energy rations may lead to over-conditioning. This is especially
important during the time calves are 3 to 9 months old or the
pre-pubertal phase of rapid mammary gland development. Excess
feeding during this period can lead to a decrease in milk secretory
tissue.
Cryptosporidiosis is perhaps one of the larger problems we face in
nursing replacements. It has been diagnosed on essentially every
dairy farm in the United States. In our experience, it strikes calves
at approximately 8 to 14 days of age, causing a profuse diarrhea
with subsequent dehydration. Morbidity (number of calves with
the disease) is high, however mortality is low with the proper
administration of fluids and supportive therapy. Therapy and
vaccinations are now being tested to eliminate this problem, but at
this time, products have not been adequately tested to advocate
their use. Adequate intake of quality colostrum and keeping calves
clean, dry and comfortable, thereby reducing stress, are the essential
components to combat cryptosporidiosis.
Vaccination protocols
Vaccination programs in the heifer herd are tailored to protect
against the diseases prevalent in the area and specific diseases on
individual farms. Herd owners should consult their herd veterinarians
for specific vaccination protocols for your area. Most vaccinations are
initiated between 4 and 5 months of age, when maternal protection
gained from colostrum has subsided. These vaccinations may need
to be repeated 3 weeks later, following label directions to ensure
peak immunity or protection. Follow all label directions, as some
vaccinations must be repeated, while others are single injections.
Vaccinations should be repeated 45 days prior to breeding or at
approximately 12 to 13 months of age. Injections are then repeated
at 18 months of age and 45 to 60 days prior to calving for sufficient
levels of immunoglobulins (antibodies) in the colostrum for the calf.
Many of the diseases that cause infertility and early embryonic death
or abortion can be prevented with proper vaccination procedures.
Again, the type of vaccination will depend on the diseases that have
been isolated on a specific farm or are found in your specific region.
Following is a list of typical management procedures and vaccination
protocols. These can vary depending on the area of your farm
location or specific diseases that have been isolated on your farm.
This protocol should only serve as a guide, as specific vaccination
questions should be directed to your veterinarian.
Suggested Vaccinations and Procedures in a Dairy Heifer Program
Birth to Calving
• The Newborn (1 to 10 days of age)
Inject with 3 cc Vit E and selenium at birth (white muscle disease)
Inject with 2 cc Vit A and D (calves are born with small reserves)
Tattoo and/or Identify calf
Begin ionophores at 4 to 5 days of age for coccidia prevention (in milk replacer or calf starter)
Bleed at 2 to 10 days of age to determine immunoglobulin levels (colostrum management)
• One Month
Dehorn with electric dehorners
Vaccinate with 7-way clostridium
Measure height and weight when removed from the hutch
• 2 to 5 Months
Clean and disinfect hutches when calf is removed
Start fly control program (summer months), concentrate on udder area if using sprays
Monitor weight, height, and body condition score
Continue coccidia control
Strategic deworming if turned out to pasture
• 5 to 6 Months
Vaccinate for brucellosis
Vaccinate with 7-way clostridium (repeat in 3 weeks)
Vaccinate for IBR, PI3, BVD, BRSV * *
(follow label directions for repeating procedure) * * (Use the modified live product – keep calves away from adult cows)
Deworm
Check for extra teats
Measure weight, height, and body condition score
• 6 to 13 Months
Monitor weight, height, and body condition score
At 13 months * *, repeat IBR, PI3, BVD, BRSV at least 45 days prior to breeding
* * (Use the modified live product – keep calves away from adult cows)
Vaccinate for leptospirosis
Vaccinate for vibrio if natural service is used
Deworm
• Pregnant Heifers
Monitor weight, height, and body condition score
Maintain sound nutritional management for adequate growth
Maintain coccidia control and strategic deworming program
Vaccinate against leptospirosis at 18 to 20 months
Vit E and selenium 45 to 60 days prior to freshening
Vaccinate with E. coli, rotavirus and coronavirus beginning 60 days prior to freshening
Source: Virginia Tech and Virginia State University Cooperative Extension;
Tom Bailey, Extension Specialist, Virginia-Maryland Regional College
of Veterinary Medicine; Julia M. Murphy, Extension Specialist, Virginia-
Maryland Regional College of Veterinary Medicine; Robert James, Professor,
Department of Dairy Science, Virginia Tech.
