Drystock cows

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A crucial time for health

The dry period is a particularly vulnerable period for dairy cows. During this period, the cow undergoes several physical changes that pose significant risks to health, fertility and future milk production. It is therefore important to pay extra attention to your cattle during this period.

The ideal drying length

Several scientific studies show that the ideal dry period for dairy cows is about 6 to 8 weeks. A dry period of this duration leads to higher milk production in the next lactation and supports better recovery and further development of udder tissue.

If you shorten the dry-off period or even omit it altogether, for example in order not to dry-off highly productive cows, this will result in lower milk production in the following lactation. It is important to note that these cows will produce extra milk before calving and the risk of problems after calving decreases.

What the ideal dry-off length is for your farm also depends on overall dry-off management. A well-thought-out approach during this crucial period can make all the difference to the health and productivity of your dairy cattle.

The ration during the dry period

A cow in dry heat has different nutritional requirements than a cow in lactation. At the beginning of the dry period, the energy density of the feed should be reduced to avoid fatigue. However, in the last two weeks before calving, this energy density should be increased again to avoid ketosis. It is crucial that your cows’ dry matter intake (DS intake) remains high during this period.

In addition, minerals and vitamins deserve extra attention to prevent problems at calving. By ensuring a well-balanced ration during dry-off, you can contribute to a smooth transition to lactation and optimize the overall health of your dairy cattle.

Standards

	Drystock 1st group (FAR-OFF)	Drystock 2nd group (CLOSE-UP)
DS(kg)	11-12	12-14
VEM/DS	790-860	900-950
RE/Ds	110-120	125-135
DVE/Ds	50-55	70-77
OEB	Positive (100)	Positive (100)
Ca(g)	40-45	45-55
P(g)	Max. 30	Max. 30
Na(g)	Max. 10	Max. 10
Mg(g)	Min. 40	Min. 45
K(g)	Max. 200	Max. 200

Minerals and vitamins

The importance of healthy calcium metabolism

Calcium metabolism plays a crucial role in the health of dry-age cows. When calcium levels in a cow’s blood become too low, production of parathyroid hormone (PTH) in the parathyroid gland increases. Sufficient magnesium is required for the production of this hormone. Next, vitamin D3 is converted by PTH in the liver and kidneys into its active form, calcitriol.

The active form of vitamin D3 (calcitriol) has several important functions:

Releasing calcium from the bones

Reducing urinary excretion of calcium

Increasing calcium absorption in the intestines

However, there are also minerals that negatively affect calcium metabolism:

Potassium: inhibits the absorption of magnesium

Phosphorus: lowers the conversion of vitamin D3 into its active form

It is important to have balanced mineral and vitamin management for your dry cows to ensure their health and prevent problems at calving.

Cation-anion balance (CAB).

In addition to adequate minerals and vitamins, the cation-anion balance (CAB) plays an important role in the calcium metabolism of dry-age cows. The CAB is the balance between positively charged ions (cations such as sodium and potassium) and negatively charged ions (anions such as chlorine and sulfur).

The formula for calculating CAB (in mEq/kg) is as follows:

Formula: CAB (mEq/kg) = (Na (mg/kg)/23,0) + (K (mg/kg)/39,1) – (Cl (mg/kg)/35,5) – ((S (mg/kg) x 2)/32,1)

A too high CAB can interfere with the action of parathyroid hormone (PTH), causing calcium imbalance. Therefore, feeds low in sodium (Na) and potassium (K) and high in chlorine (Cl) and sulfur (S) are preferable. You can further reduce CAB by adding anionic salts to the ration.

The table below shows the average CAB values of some feeds commonly used in drystock.

	Average CAB
corn silage	173
grass silage	386
straw	185
hay	440
press pulp	40

Optimize the calcium metabolism of your cows

Avoid a ration with too much calcium to prevent lazy calcium metabolism. At calving, calcium requirements increase, and slow clearance can lead to calf disease, afterbirth problems and abomasum. Add extra vitamin D3 and magnesium and keep the cation-anion balance (KAB) as low as possible to support the health of your cows.

Drystock rations in practice

If possible, divide dry cows into two groups: far-off and close-up. For a six-week dry period, divide this period into four weeks of far-off and two weeks of close-up.

Depending on the results of your analyses of your corn and grass silage, you can adjust the sample ration below when working with two groups.

Far-off (4 weeks):

±6 kg DS corn silage ≈ 18 kg corn silage
±3 kg DS grass silage ≈ 6 kg grass silage
3 kg straw
0,5 kg soybean meal
100 gram Herbamin-dry

Close-up (2 weeks):

Same ration as in the far-off
+2 kg transition mixture

Often your group of dry cows will be too small to work practically with 2 groups. Then it is best to choose 1 group with a ration with a slightly higher VEM/DS for the whole dry period than in the far-off group. It is still important to monitor dry matter intake and minerals.

	Cause	Symptoms	Prevention
Milk disease	Deficiency of calcium in the blood	– No appetite- Ears cold- Cow cannot straighten- Does not make manure or urine	Supporting calcium metabolism during dry heat
Lingering milk disease	Excessive negative energy balance after calving causing the cow to break down body fat	– Sluggish- Little appetite- Breath smells like acetone	– Prevention of excessive negative energy balance- Adjusted ration in the close-up with liver-supporting vitamins
Metritis	Imbalance between the cow’s resistance and the number of bacteria entering the uterus	– Stinky vaginal discharge- Fever- Decrease in appetite- Decrease in milk production	Optimizing resistance and hygiene
Lebmaag-draaiing ???	Multifactorial:- Dairy disease- Lingering milk disease- Little rumen filling- Large empty belly after calving- Staying on afterbirth- Twin gestation	– Decline in appetite- Ping sound on left flank- No fever- No rumen sound- Decline in milk productio	– Prevent metabolic problems- Give lukewarm water after calving- Adjusted rations
Opblijven van de nageboorte ???	Multifactorial:- milk fever- lingering milk fever- reduced resistance- difficult calving	Afterbirth did not come off within 12 hours of calving	– Adjusted ration- Reduce stress

Fertility in dry heat

The close-up period during dry heat is crucial to the fertility of your cows. The development from a primordial follicle to a mature follicle takes about 60-80 days. So the follicle you want to inseminate in the first few months of lactation begins to develop during dry-off.

For good follicle quality, you can do the following:

Increase energy density: This promotes proper follicle maturation.
Provide antioxidants (such as vitamin E and selenium): These protect against oxidation and increase resistance.
Geef een hoge dosis choline: Dit zorgt voor een gezonde lever en een optimaal metabolisme.
Verhoog het β-caroteen: Dit verbetert de bronst en helpt bij het behoud van de dracht.

View the full article from Landbouwleven.be here