Vet Georgette explains why focusing on nutrition is essential for a successful dry off.
The dry period is an important time of the season for heavily pregnant cows, as it is a time for ‘restoration’ and ‘preparation’.
Restoration: Milk glands in the udder need some time to recover in order to get ready for another year of milk production.
Preparation: The cow can focus on putting more energy into her fast growing foetus in order to have a 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 in the 1-2 days leading up to dry off (not always achievable in high producing cows), before completely stopping 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 elements like calcium, magnesium and phosphorus will change;
Cows will need to deal with a degree of stress - this comes as the result of the range of changes they are going through, and being transported to winter grazing, etc.
Principles of nutrition at dry off
With an increasing number of farmers using an internal teat sealant-only in their low somatic cell count cows, and selective dry cow (combo) therapy in the remainder of the herd, it has become even more important to focus on overall drying off management, and nutrition in particular.
So, let’s look at a few base principles when it comes to nutrition and management around the time of drying off:
Looking after your herd’s body condition:
This should be an important focus point in autumn. Making decisions early, such as drying off light cows early, changing milking frequency etc, is crucial.
If you had individual body condition scores (BCS) done in late summer and mid autumn, you can ask your KeyVet to make a dry off list with individual BCS data linked to calving dates. This can help you to work out the ideal dry off date to reach the targeted BCS at calving.
Reducing milking frequencies (i.e. milking 16 hourly, or 10 milkings in 7 days) from late summer/early autumn can be a useful management strategy to preserve BCS well ahead of dry off time.
Twice a day milking?
If you are planning to continue on twice a day milking until the end of the season, then going once a day (OAD) only 2-3 days prior to drying off will be an important tool in dry off preparation.
The impact of making a sudden change, resulting in milk volume reduction, is largest in the first few days.
Once you stay on OAD for longer than 3-4 days, this becomes a new routine and you often see cows go slightly back up in production.
From now onwards, dry off any cows producing 5L or less (approx 0.4 kgMS) immediately. Continuing to milk too many of these low producers can cause your bulk milk somatic cell count to go up.
Higher producers (those still doing >15-20L/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 dry off. While doing so would probably cause the required drop in milk, it would also make the lactating cows lose body condition because their energy requirements (foetus + milk production) are not being met.
There are, however, ways to make cows drop milk production without compromising their BCS by reducing the milk-driving protein components of the diet.
Examples of high protein feeds you want to reduce are
High quality grass silage/baleage
Lucerne, DDG, soya and crops like rape and kale etc.
Reducing the overall protein content of the diet can be done in the few days leading up to drying off. A big focus should be on keeping cows content and full, so you can replace these feeds with low protein options, such as 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 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 its high sugar but low overall protein content, fodderbeet feeding often reduces milk yields, in particular if fed in increasing amounts (4kgDM+/c/d). Just watch out for acidosis!
When it comes to calcium and magnesium supplementation leading up to drying off, it is highly recommended you continue with limeflour (75-100 gms/c/d) and causmag (25-30 gms/c/d), 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 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 them going down during transport.
Dry off day
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;
Trucking cows immediately after they have been dried off is a useful tool to reduce milk production, as taking cows away from their normal environment stimulates their milk let down;
Ensure there is enough roughage for them to eat on arrival;
Never let hungry, freshly dried off cows go onto crop without having them filled up on roughage first;
If you started transitioning cows on fodderbeet pre-dry off, then keep them on their daily fodderbeet feeding amounts.
Over the course of the 7-10 days post drying off, keep cows full with lower quality feeds and gradually increase the amount of crop, if that is what you are wintering your cows on, to avoid acidosis or too much milk drive.
Our KeyVet team at VetSouth is experienced and knowledgable in drying off nutrition, and know our regions well. If you need any support or have any questions, please contact your nearest clinic.
- Georgette Wouda