At the time of writing of this article, the Southern regions are quite desperate for rain, and if we don’t get any decent moisture soon this article will be less relevant as cows will start to drop in milk production naturally due to a lack of feed availability.
For now, let’s stick with the “glass half full'' scenario that we will get rain soon and that the grass will grow and that we therefore will deal with our “normal” southern autumn high protein grass leading to dry-off.
The dry period is an important time of the season for the (highly pregnant) cows as it is a time for “restoring” and “preparation”. The restoring part is linked to giving the milk glands in the udder some time to recoup and restore in order to get ready for another year of milk production. The preparation part is the bit where the cow can focus on putting more energy into her fast-growing foetus in order to have smooth calving that marks the start of another lactation year.
There are a lot of changes that occur in a dairy cow around the time of drying off in order to transition her from a lactating cow into a dry cow:
- Milk production needs to slow down to ideally 5-10 L/day or less, in the days leading up to dry-off and then needs to completely stop in the 1-2 weeks after the final milking
- The rumen needs to adapt to a dry cow diet, which is often very different in both nutritional quality and quantity.
- The cow’s requirements for calcium, magnesium etc will change.
- Cows will need to deal with a degree of stress: stress due to the range of changes they are going through (cows are routine animals, they don’t like change), the stress of being transported to winter grazing, etc.
With an increasing number of farmers using an internal teat sealant (ITS) only in their low SCC cows and selective dry cow (combo) therapy in the remainder of the cows, it has become even more important to focus on overall drying off management and nutrition in particular.
So let’s focus on a few base principles when it comes to nutrition and management around the time of drying off:
Body Condition Score
Looking after your herd’s body condition should be an important focus point in autumn. Making decisions early by drying off light cows early, changing milking frequency etc are crucial. If you had individual BCS done in late summer and mid autumn you can ask your KeyVet to make a dry off list where individual BCS data is linked to calving dates in order to work out the ideal dry-off date to reach the targeted BCS at calving.
TAD to OAD
With the dry conditions and feed shortages we see this year, it is highly likely that very few farms will still be milking twice a day (TAD) come May. However, if you are planning to continue on TAD milking until the end of the season, going once a day (OAD) only 2-3 days prior to drying off will be an important tool in the dry-off prep. The impact of making a sudden change, resulting in milk volume reduction, is the largest in the first few days following the routine change.
Any cows from now on that only produce 5L or less (approx 0.4 kgMS) per day can be dried off immediately because if you continue to milk too many of these low producers it can cause your BMSCC to go up.
Higher producers (i.e. doing still 15-20L or more/1.25kgMS+) require some slowing down, but this can be done reasonably fast.
Don’t try to feed your lactating cows a dry cow diet in the weeks leading up to drying off; whilst this probably will cause the required drop in milk, it will also make the lactating cows lose body condition because their energy requirements (foetus + milk production) are not met.
There are ways to make cows drop milk production without compromising her BCS by reducing the milk driving protein components of the diet. Examples of high protein feeds you want to reduce are: fresh grass, lucerne, DDG, soya and crops like rape and kale etc. You can replace these feeds with low protein feeds like whole crop silage, low protein silage, baleage and/or hay. If you are feeding things like molasses, barley/wheat or PKE in an in-shed feeding system, then you can carry on feeding those feeds as they are low to moderate in protein and will help with maintaining condition.
Transitioning cows pre-dry off onto fodderbeet crops is fine. With their high sugar but low overall protein content (watch out for acidosis!!), fodderbeet feeding often reduces milk yields, in particular if fed in increasing amounts (4kgDM+/c/d).
Reducing the overall protein content of the diet can be done in the week leading up to dry off. A big focus should be on keeping cows content and full. For example, if you are trying to reduce the amount of fresh grass that is being fed, you will need to keep the cows full-on bulky feeds like a combi of (whole crop/grass) silage/baleage and hay/straw. In-shed feeding levels can remain the same.
When it comes to calcium and magnesium supplementation leading up to dry off, it is highly recommended you continue with limeflour (75-100 gms/c/d) and causmag (25-30 gms/c/d) supplementation, either through the in shed feeding system or dusted on silage/baleage/grass. You can feed limeflour and causmag either until you dry off or even carry on for another week or so after drying off. If cows will be transported immediately post dry off, this Ca/Mg supplementation is even more important as it will prevent cows from going down during transport.
When Dry-Off Comes
On the day of dry-off, take out all high protein feeds but fill cows up with bulky, low protein feeds in order to keep them full and content: hay, good quality straw and low protein baleage are great options. If cows are not used to eating a lot of straw, don’t try to force them all of a sudden to eat 6 kgDM of straw and think they will be happy, they probably will use it as bedding…
If cows stay at home after dry-off, continue your feeding regime ideally as you’ve done on the day of dry-off: keep them full with bulky, low protein feeds to keep them settled. If you started transitioning cows on fodderbeet already pre-dry off then keep them on their daily fodderbeet feeding amounts. If cows don’t get started on winter crops until after dry-off, then ensure you start feeding this crop in small amounts and build up gradually to avoid either acidosis (swedes, fodderbeet etc) or too much milk drive (in case higher protein crops like kale and rape).
Over the course of the week to 10 days post drying off gradually drop the total amount of DM offered to your required dry cow feeding levels (12-14 kgDM/c offered depending on the size of cows and wintering conditions, wastage etc).
- Georgetta Wouda