One of the most critical periods in the life of a dairy cow is the calving transition period, i.e. transitioning from being a dry cow to a lactating cow.
In my opinion, this is something that has traditionally been not well considered, and there are significant animal health and production benefits if prioritised!
Conversely, if done poorly, cows will enter into a negative energy balance, lose excessive condition and often enter a state of subclinical ketosis (SCK). Recent data has shown that, on average, 75% of cows within New Zealand are affected by subclinical ketosis at some stage during the calving period. There can be large variations between herds, with different numbers of cows affected depending on how well each individual farm manages this important transition period. Down cows with metabolic issues are also significantly more likely to develop SCK as a secondary result from being down.
If a cow has SCK they will:
Be 3x more likely to die or be culled in the first 30 days of milking;
Have a 7% reduced 6-week in-calf rate;
Be 3.5x more likely to develop endometritis/metritis (dirty cow);
Have 7% less production overall for the season.
The calving transition period is defined as the 3 weeks pre-calving and 3 weeks post-calving, so analysing this whole period is crucial for improving transitioning your cows into lactation.
Pre-calving
When feeding crops with high dry matter, such as fodderbeet, a cow's rumen decreases in size and muscle thickness and the rumen papillae halve in length. This renders the rumen unable to physically digest the 15+kgDM of grass/roughage that is required to be eaten when a cow calves. So, the main aim of this period is to build up rumen capacity and develop the correct bacteria in her rumen to enable her to eat the required amount of grass on the day she has her calf. This will help to kick her out of that negative energy cycle as quickly as possible and significantly reduce her risk of developing SCK.
Options that can help with developing the rumen include:
Pre-transitioning the cows in their calving groups while still on crop. For example, reduce the amount of fodderbeet or swede and increase the amount of baleage they are getting. Ideally to a 50:50 ratio for 3 weeks pre-calving.
Proactively drafting cows into their springer mobs so they can spend the most amount of time there as possible. Plan to have them in their springer mob for 14 days on average. If space on calving pads is an issue, consider having a “close springer mob” on the pad, and a “far springer mob” on a nearby paddock.
Aiming to have the springer diet as close to the colostrum cows/milkers diet as possible. Ensure this diet has the right amount of energy so that they are not going into a negative energy balance pre-calving.
Feeding the correct minerals required to reduce the number of cows going down. Specific pre-made mineral mixes that aim to reduce the DCAD (dietary cation-anion difference) of a cow have a significant effect on reducing down cows.
Consider the use of Rumenox (monensin) over the calving period at a minimum. Extensive studies have shown that this reduces SCK by a whopping 30-40%. It's also a great protector against bloat and it increases milk yield.
Calving
The main aim of this period is to get cows back to eating as fast as possible and doing everything practical to reduce the chance of cows developing metabolic issues.
This could include:
Preventing cows that have just calved from standing for long periods on concrete and away from feed.
Reducing the amount of time that a cow has to form a bond with their calf - ideally picking calves up 3x per day.
Offering as much feed, in different forms, as possible to encourage feed intake. For example, adlib grass and baleage, plus some form of concentrate feed in the shed or in trailers in the paddock, if possible.
Dusting the colostrum cow's feed with the correct levels of magnesium and calcium, and also dusting both baleage and grass, as required, to ensure every cow is getting what they need.
Consider the use of calcium bolus (e.g. Calpro Bolus) when cows calve, especially for your high risk cows to prevent them from going down. High risk cows include 6+ year old cows, high producers, twin births, assisted calvings, etc.
Post-calving
To ensure cows bounce back from calving, the main aim of this period is to reduce the demands on the cow so that they can get out of that negative energy balance as quickly as possible.
Processes that could support this include:
Utilising once-a-day (OAD) milking for the required time it takes for each cow to be fully recovered and eating post-calving.
Use a system that is practical for your farm. This might be where cows stay on OAD milking for 14 days post-calving and are then shifted to twice a day if their “belly is bigger than their udder”. Or, it might be doing OAD milking for all milkers for 4-6 weeks at the start of calving and then keeping cows in the OAD colostrum mob for longer in the second half of calving.
OAD milking during this crucial period has anecdotally been shown to not reduce milk production for the season because the cows are in better condition and milk for longer. Also, the improved reproduction performance will increase days in milk the following season, so the benefits will build.
Utilising wearable technology.
Farms with wearable technology (e.g. collars/tags) can use rumination minutes as a guide for each individual cow to see if they have recovered from calving. Once recovered, they can then be shifted to twice a day milking.
To summarise
The transition period from being a dry cow to a lactating cow during calving is one of the most critical times in the life of a dairy cow. Farms that get this right are the ones that tend to have the least animal health issues and are the best performing when it comes to milk production and reproduction.
There is no one-size-fits-all approach to this period, so take a good look at your system and see if there are different things that you can implement to improve the transition on your farm.
If you have an issue with many down cows in spring, then looking into ways to help prevent this will be a crucial first step – you may find that by transitioning cows properly these cases disappear.
It is also really worthwhile to do a ketosis check on your farm, by sampling some bloods from cows post-calving to see how many on average have SCK. This is a very simple test that can give you a good indication of how well your cows are transitioning.
As always, you can discuss different options with your KeyVet for advice. If this period is done right, you'll be amazed at how easily the rest of the season falls into place for your cows!
