The transition period is defined as the period between the last three weeks before calving to the first three weeks after calving. Over 80 per cent of health issues experienced during lactation will occur or are caused by events during this six-week period.
The following key components are essential for a successful dry cow management regime:
The ideal dry cow period is eight weeks. However, a longer dry period of ten to fourteen weeks is required for animals in sub-optimal body condition, carrying twins, and first lactation or older animals. In an ideal situation, body condition score would be assessed six-to-eight weeks prior to drying off with diets adjusted accordingly i.e. increase feeding to under-conditioned animals.
Dry cows should have a minimum of 0.66m feed space per cow available to support optimal dry matter intake (DMI). Fresh feed should be supplied daily with optimal chop length if feeding via TMR. Clean water should be easily accessed at all stages. Adequate clean and comfortable resting areas should be made available for dry cows.
Any hoof health and lameness issues should be treated before the drying off process begins, and heavily pregnant cows should be handled with care at all stages. Foot bathing should be a regular occurrence for both dry cows and in calf heifers. Farmers should consult with their vet on recommendations regarding liver fluke, rumen fluke, worm treatments and selective dry cow treatments.
Ideally cows should be dried off with a BCS between 2.75 and 3. Target body condition score at calving is 3 to 3.5 for first calving heifers, and 3 to 3.25 for cows. Cows calving with a BCS in excess of 3.25 have depressed appetites and lose more body weight in early lactation. This leads to increased incidences of metabolic disorders which will have a negative impact on animal health and milk production. Dry cows should be grouped according to their BCS and their feeding programmes adjusted accordingly (to correct BCS of animals outside of the optimal range).
The drying off phase is important as the signal to cease milk production must be given to the cow. This can be achieved by a combination of feeding and management. In general, the farmer reduces meal feeding to zero over a few days and increased the proportion of straw in the diet. Then the cow can be dried successfully and usually the cow remains on a high straw died for three to five days to reduce gorging of the udder. The cow is gradually changed to the far-off diet then over a period of a few days. Straw is a high fibre ingredient with low energy and protein levels hence it's benefits in stopping milk production.
In the far-off dry cow period cows are normally fed high fibre diets. The amount of straw included in a winter diet depends on the BCS of the cow and the energy level of the silage being fed.
The table below outlines how feed should be based on silage quality and body condition score.
| Silage DMD | BCS 2.5 (12-14 weeks dry) | BCS 2.75 (8-10 weeks dry) | BCS >3.0 (8 weeks dry) |
|---|---|---|---|
| >72 | Silage +1kg meal | Silage ad-lib | Silage Restricted |
| 68-72 | Silage +2kg meal | Silage +1kg meal | Silage ad-lib |
| 64-68 | Silage +3kg meal | Silage +2kg meal | Silage +1kg meal |
It is vitally important that cows get the correct balance of energy and protein to meet the increasing nutritional demands as calving approaches. High quality protein is recommended in the close-up period to ensure the production of sufficient quantity and quality colostrum. A 14 percent protein diet is targeted on many farms, but this can only be done if the forages are analysed. Excess dietary protein pre calving can increase the risk of gorging udders and may increase the risk of mastitis.
In the close-up period, it is crucial to control the dietary cation-anion balance (DCAB). This is the sum of sodium and potassium in the diet less chlorine and sulphur (divided by their molecular weights). It is measured in mEq/100g dry matter. High DCAB silages with high potassium and/or high sodium content, need careful management and supplementation to ensure the prevention of milk fever. The target forage DCAB level for dry cows is < 150 mEq/kg.
Diets can be formulated to partial or full DCAB status depending on the cow type, production level and previous history of calving difficulties. Devenish provides a range of products that can be incorporated into the diets of dry cows to counteract high DCAB forages. These include, Dry Cow Salts, Devenish Mag12 and SoyChlor. Dry cow salts are anionic salts which when fed reduces the DCAB of the diet. Mag12 is a 99 percent bioavailable source of magnesium. SoyChlor is an anionic product which improves calcium release from bone and then increases the absorption by the gut by acidifying the blood. It works to prevent potential metabolic disorders in early lactation by reducing the blood pH. Producing a partial anionic state, SoyChlor also provides high levels of rumen undegradable protein and is designed to be fed in the close-up dry cow period at an intake of 0.75 - 1.5 kg per head per day (level adjusted to match the DCAB of the diet).
Ideally cows should be fed dry cow mineral premixes for eight weeks prior to calving. In calf heifers should be fed for an extended period of 12 weeks before calving. These premixes should be balanced for major mineral, trace element, and vitamin requirements.
Dry cow minerals can be fed in a TMR or scattered on top of silage. If spreading minerals on top of silage it is necessary to spread the minerals at least twice per day. It is important to note that all dry cows and in calf heifers reduce their dry matter intake by 30 to 40 percent for the last four to seven days before calving. Hence on many farms the dry cow minerals are included as part of the concentrate fed, whereby half the concentrate and mineral are fed in the morning and the remainder is fed 12 hours later in the day. The main reason for this is to ensure that the cow receives adequate magnesium right up to the time the cow calves. Remember the cow cannot store magnesium for longer than 10 to 12 hours, hence the reason for feeding twice daily.
By implementing effective dry and transition cow management, dairy farmers have the potential to achieve the basis targets as set out in the following table. This should allow dairy farmers to reap the rewards of healthy, lasting, productive cows.
| Health Challenges | Target Cases Within the Herd |
|---|---|
| Milk Fever | 0-3% |
| Retained Placenta | 0-5% |
| Displaced Abomasum | <3% |
| Culled Cows in First 60 Days in Milk | <3% |
If you have questions about dry and transition cow management, please contact Dr Morgan Sheehy on +353 86 827 6506 or email morgan.sheehy@devenish.com
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