As we enter into January and into a new year, the transition period for your cows will need to be managed, as cows are going to be calving down in the next number of weeks.
The transition period is defined as the three-week period prior to calving to the three weeks post-calving, which for a number of herds calving in late January, is going to be around now.
Getting the transition period right, with minimum stress and maximum comfort for the cow is a key determinant of the future productivity and performance in dairy cows.
If this period is not managed correctly, it can lead to higher disease incidence, poorer production and reproduction and higher herd removal rates.
The majority of farmers observe the highest incidence of disease within the first three weeks after calving, with milk fever posing the biggest threat post-calving.
The transition period
Ensuring cows are calving down with a body condition score (BCS) of 3 to 3.5 with 3.25 being the ideal is essential for the cow’s health and future production.
To achieve this, silage quality has to be decent with 68% dry matter digestibility (DMD) silage supporting moderate BCS gain provided the cows have an adequate dry period and were dried off at a BCS of 2.75 to 3.0.
BCS during the transition period will have to be actively monitored prior to calving, so farmers can intervene on time if certain cows have appeared to fall behind.
Later calving cows will have to be checked regularly for BCS as they will more than likely have a longer dry period and may need their silage restricted three to four weeks prior to calving, as you don’t want them over a BCS of 3.5.
Overfat cows will have a higher risk of milk fever and metabolic disorders arising.
Ensure a constant supply of pre-calving minerals of 120g/cow/day feeding rate and if they are getting dusted onto silage, it is advised that the minerals are spread twice daily, with 60g/cow in two feeds six to eight weeks pre-calving.
Cows need adequate phosphorus (P), magnesium, trace elements and vitamins to be supplied to the cow during this period of rapid foetal growth.
Dry cows will need 0.4% of dry matter (DM) magnesium in the diet from at least four weeks pre-calving, while the lactating cow will require 0.3% of DM magnesium for approximately four months post-calving.
High levels of of potassium (K) in grass silages can be common due to the timing and volume of slurry application and high K silage can interfere with the absorption of magnesium which can result in milk fever cases.
Silages with a K level of above of 2.4% should not be fed to cows two to three weeks before calving to minimise the risk.
Any indications of sub-clinical milk fever, retained cleanings, mastitis, or any metabolic issues can often be overlooked during the busy time of calving which can negatively impact performance for 2025. Farmers should keep records and seek advice.