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Author: J.F. Cote
Introduction
Dairy cows require a rest period between lactations. The udder and the digestive
tract especially benefit from rest during the dry period. The dry period is
actually the beginning of the next lactation. It is the best time to institute
management practices to prevent health problems and to ensure good production
in the lactation to follow. This Factsheet describes practices which aim to
promote good health and performance in early lactation cows.
Drying-Off
Drying-off occurs when milk is left in the udder for 18 hours or more. The resulting
pressure causes the milk glands to stop producing droplets of milk. This eventually
leads to reduction in the size of the udder.
The standard recommendation has been to withdraw concentrates from the cow's
ration for about one week and then abruptly stop milking. Moving late lactation
cows to a different stall or loose pen and restricting water intake reduces
milk production. Cows which are producing in excess of 25 kg of milk per day
are difficult to dry off abruptly and may be more susceptible to new intramammary
infection.
Recent research suggests removing the concentrate ration for 7 to 14 days accompanied
by once a day milking may be a good way to dry off cows. Cows dried off in this
manner developed fewer new mastitis infections than cows which were dried off
abruptly without a change of ration.(1)
Cows should have a dry period of about 60 days. During this time they should
be separated from lactating cows and grouped according to early dry period and
close-up to calving. This grouping is to facilitate nutritional management.
Dry cows should be housed in clean, dry, comfortable loose pens or paddocks.
Exercise is important to maintain normal body functions and muscle tone.
Early Dry Period
The early dry period comprises the first 4-5 weeks after drying off. During
this period attention should be given to mastitis prevention, vitamin supplementation
and body condition.
Mastitis Prevention
Dry cow intramammary antibiotic treatment is necessary to prevent new udder
infections in the early dry period. It also eliminates sub-clinical infections
persisting from the previous lactation. Selection of an infusion product should
be based on your veterinarian's advice as well as the antibiotic sensitivity
patterns for known mastitis agents in the herd.
Two standard recommendations should be noted. Immediately after the last milking,
infuse all 4 quarters of each cow with the appropriate intramammary slow release
antibiotic preparation. Before treatment, prepare teat ends aseptically with
teat dip and alcohol swabs. This prevents environmental mastitis bacteria from
being accidentally introduced into the teat on the infusion cannula.
Vitamin Supplementation
Cows in late pregnancy have a high requirement for vitamins A, D, E and selenium.
Vitamin A is known to prevent premature, weak and stillborn calves and retained
placenta. Providing vitamin A orally in a commercial dry cow premix (100,000
IU/day) or by intramuscular injection at drying-off prevents any deficiencies.
Vitamin E and selenium supplementation are necessary to enhance the body defences
to protect the cow from challenge by infectious agents. Recommended levels for
confined Holstein cows in areas of known selenium deficiency are vitamin E,
1000 IU/day and selenium, 3 mg/day during the dry period.(2) This is best administered
by inclusion in the ration.
Dry cow rations should be evaluated and balanced to provide correct amounts
of vitamins A,D,E and selenium.
Body Condition
Early lactation cows have a high energy requirement for milk production and
reproduction. They also have a reduced dry matter intake (DMI) for the first
60 to 70 days in milk. During this period they must utilize stored body fat
as a source of reserve energy.
Body condition scores indicate the amount of stored energy available to the
cow. In early lactation one kg of body fat provides the energy needed for 7
kg of milk. Lactating cows will utilize about 1 kg of stored fat daily in order
to meet their energy requirements. If cows utilize more than 1 kg/day especially
in the first 14 days in milk, fatty degeneration of the liver is excessive.
As a result ketosis may occur and the interval to conception will be prolonged.
Cows gain condition most efficiently during late lactation. Ideally cows at
dry-off time should have a body score of 3.5-4. No weight loss or gain in condition
should occur during the dry period unless needed. Dry cow rations should be
evaluated and balanced to meet daily protein and Total Digestible Nutrients
(TDN) requirements. National Research Council 1989 recommends 1.35 kg crude
protein and 6.3 kg TDN daily for a 700 kg dry cow.
Close-up Dry Cows
The close-up dry period comprises the 2 to 3 weeks prior to calving. During
this time lead feeding, milk fever prevention and maternity facilities must
be emphasized.
Lead Feeding
In late pregnancy the enlarging uterus occupies more of the abdominal cavity.
This reduces the rumen's capacity for feed. Late pregnancy cows have a limited
DMI of about 2% of body weight (BW) daily. At this time a good roughage base
must be established. Preferably this should consist of about 12 kg of corn silage
and free choice hay. Lactating cow grain ration can then be gradually increased
to 4-5 kg/day by calving day. Lead feeding of grain ration starting 2 weeks
prior to calving helps to avoid digestive upsets resulting from abrupt changes
from pre- to post-calving rations.
After calving, increase grain gradually (maximum 1 kg/day) as production increases
and appetite increases. Increase the protein supplement first to stimulate milk
production and the grain ration second. During lactation the concentrate to
roughage ratio on a dry matter basis should not exceed 60:40. Feeding programs
and total mixed rations (TMR) which exceed this ratio run the risk of predisposing
cows to abomasal displacement, laminitis and off-feed problems.
Introducing close-up dry cows to a lactating cow TMR is a form of lead feeding.
If possible, the dry cows should receive a low calcium TMR formulated for low
production cows for no longer than 5 days before calving. A longer introductory
period could predispose mature cows to milk fever.
Milk Fever Prevention
Calcium
A dairy cow's requirement for blood calcium increases suddenly with the onset
of calving and during early lactation. When calcium levels in blood are too
low, cows may develop milk fever at calving time. In addition, their appetite
and muscle tone will be poor during the first two weeks of lactation. Good muscle
tone improves the function of the digestive tract and also assists the involution
of the uterus. Good appetite increases DMI and milk production and helps to
prevent ketosis.
A cow in early lactation milking 40 litres/day requires about 56 grams of blood
level calcium daily from her diet and bone storage reserves.
A cow's DMI is limited during early lactation. Therefore, it is difficult for
the cow to obtain enough calcium from the diet to meet requirements. For optimum
health and performance, dairy cows need to draw on reserve calcium which is
stored in their bones.
If the cow is stimulated to release reserve calcium from bone, 10-15 grams daily
is available (Figure 1). This amounts to 20-25% of the daily requirement for
blood level calcium. However, it takes about 14 days to condition a release
of stored calcium into the blood from bone. It is essential to start this conditioning
at least two weeks before calving by feeding close-up dry cows less than 100
grams of dietary calcium/day (70 grams/day for small breeds). This feeding strategy
stimulates the cow to begin mobilizing reserve calcium prior to calving.
Figure 1. Calcium Removal from Bone in Early Lactation. The
10-15 g of reserve calcium available in early lactation is especially important
because it is cell level calcium. A fresh cow needs 56 g of cell level calcium
per day for 40 kg milk production.
The addition of anionic salts to the close-up dry cow grain ration will also
stimulate the release of reserve calcium from bone. Ammonium chloride and magnesium
sulphate are examples of anionic salts. Most feed companies have a dry cow supplement
containing anionic salts. However, anionic salts are somewhat unpalatable, so
they must be thoroughly mixed with grain or a TMR and the dose divided into
2 daily feedings. Anionic salts should not be fed for more than 3 to 4 weeks.
Magnesium
A high incidence of milk fever has been reported in dairy herds with an insufficient
supply of magnesium during the dry period.(3) Cows deficient in magnesium had
low rates of calcium mobilization compared to cows which received sufficient
magnesium. Milk fever prevention includes balancing dry cow rations for calcium,
phosphorous and magnesium. The following levels are recommended: calcium 0.39%,
phosphorous 0.24%, and magnesium 0.23% in the total diet.
Free choice mineral feeding may result in mineral imbalance. As an example,
excess phosphorous may interfere with Vitamin D metabolism and cause milk fever.
Minerals should be fed in measured amounts daily.
Udder Edema Prevention
Dry cows should be offered cobalt iodized salt at the rate of 30-40 grams/day.
Excess sodium which comes from salt can cause udder edema in dry and springing
cows.
Maternity Pens
Maternity pens should be clean, comfortable and provide good footing. Third
lactation and older cows are most susceptible to milk fever and related post-calving
complications such as retained placenta, slow uterine involution, poor appetite,
and ketosis. Placing dry cows in a maternity pen or calving paddock for two
weeks before calving is a good way to control the diet to prevent metabolic
problems. If a cow develops milk fever in a clean comfortable maternity pen,
complications such as mastitis and muscle damage are less likely to occur and
treatment will be easier.
Calving facilities must be dry and clean to prevent infectious diseases such
as mastitis, retained placenta, infection of the uterus and calf scours.
Summary
The dry cow management procedures described in this Factsheet are intended to:
- Prevent and eliminate mastitis by proper drying-off procedure, dry cow treatment
and clean dry comfortable housing.
- Strengthen the cows' immune systems and body defences by ration balancing
and supplementation of vitamins A, D, E and selenium.
- Ensure sufficient body condition to provide reserve energy to meet requirements
for milk production and reproduction in early lactation.
- Prevent digestive upsets and displaced abomasums by proper forage feeding
and lead feeding grain to the closeup dry cows.
- Prevent milk fever by restricting dietary calcium for the last 2 to 3 weeks
of the dry period and/or feeding anionic salts to stimulate the release of
stored calcium from bone at calving time.
- Stimulate and maintain aggressive appetite during the dry period and early
lactation to ensure maximum DMI, good rumen-fill, normal utilization of stored
fat and high milk production.
- Prevent udder edema by proper sodium intake and exercise.
- Prevent calving injury, retained placenta, infection of the uterus, mastitis
and calf scours by providing a clean dry maternity pen with good footing.
Division:
Agriculture and Rural History:
Written by:
J.F. Cote - Health Management Veterinarian/OMAF
References
1. Oliver, S.P., et al. Influence of Different Methods of Milk Cessation on
Intramammary Infections During the Peripartum Period. Proceedings of International
Symposium on Bovine Mastitis, 1990; 92-97.
2. Smith, L., et al. Vitamin E and Selenium Can Help Lower the Incidence of
Mastitis. Large Animal Veterinarian, November/December 1988.
3. Van Mosel, M., et al. Effects of Deficient Magnesium Supply During the Dry
period on Bone Turnover of Dairy Cows at Parturition. The Veterinary Quarterly,
Vol. 13, No.4, October 1991; 199-207.
Author: J.F. Cote
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Who saw this article? New!
 DISCUSSIONS ON THIS ISSUE.
 
| 04/13/2007 |
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Good article; may be helpful to all advisors. | Answer Checked by Engormix.com  |
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| 03/22/2008 |
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Martine Jourde
Vet/
Quebec - Canada |
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Very interesting article!
We would suggest some modifications to the recommended feed program because of the incidence these practices have on the cows health.
Quote :
The standard recommendation has been to withdraw concentrates from the cows ration for about one week ( too short, 2 to 4 weeks would be preferable, specially for protein concentrates while the production period ends and the milk production naturally slows down) and then abruptly stop milking.
...
In late pregnancy the enlarging uterus occupies more of the abdominal cavity. This reduces the rumens capacity for feed. Late pregnancy cows have a limited DMI of about 2% of body weight (BW) daily. At this time a good roughage base must be established. Preferably this should consist of about 12 kg of corn silage(This is way too much!) and free choice hay. Lactating cow grain ration can then be gradually increased to 4-5 kg/day (Much too rich in protein. This will sometimes kill the cow!)by calving day. Lead feeding of grain ration starting 2 weeks prior to calving helps to avoid digestive upsets resulting from abrupt changes from pre- to post-calving rations.
After calving, increase grain gradually (maximum 1 kg/day) as production increases and appetite increases. Increase the protein supplement first to stimulate milk production and the grain ration second(Please inverse this proposal because the liver will be surcharged and acetonemia will result 3 to 6 weeks after calving). During lactation the concentrate to roughage ratio on a dry matter basis should not exceed 60:40. Feeding programs and total mixed rations (TMR) which exceed this ratio run the risk of predisposing cows to abomasal displacement, laminitis and off-feed problems.(THIS IS A BRILLANT OBSERVATION)
Dry cows should be offered cobalt iodized salt at the rate of 30-40 grams/day. Excess sodium which comes from salt can cause udder edema in dry and springing cows.(and also an excess of protein).
My comments in ().
Clement Doyer, Labo Solidago, Canada | | Answer Checked by Engormix.com |
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