Getting the transition cow period right on farms is vital to cows having a successful calving period and subsequent lactation.
The autumn-calving season has started on some dairy farms while for others it is still a number of days before the first cows are due to calve.
The transition period is the period three weeks pre-calving and three weeks post-calving.
Transition cow
During this period a dairy cow faces many physiological challenges, but supplementing cows with minerals pre-calving can reduce the risk of production diseases.
A prevention approach to reduce the occurrence of production-related diseases is better than dealing with the issues once they have occurred.
Cows with milk fever are eight times more likely to develop mastitis early in lactation, and negative energy balance in late-pregnancy is more likely to develop a displaced abomasum (LDA) in lactation.
Ahead of calving, dietary calcium levels should be kept low.
The risk of milk fever is reduced if dietary calcium levels can be maintained below 0.5% of dry matter (DM) before calving.
In terms of mineral specification, the main points are:
- Low calcium (<1.1%);
- 20-25% magnesium;
- 2-5% phosphorus (P) (feed at higher rate if forage P content is low);
- Vitamin D – at least 12,000 units/100g;
- Trace minerals – copper, zinc, selenium, manganese, iodine and cobalt with protected sources included where required.
Minerals are usually fed at a rate of 120g/cow/day; if you are dusting minerals on silage it is better to do it twice a day with 60g.
It is unlikely to not have some issues during the calving season, but mitigating the risks will reduce the number and the severity of the issues that do occur.
Management
Body condition score (BCS) monitoring is also vital during the lead up to calving, although it may be difficult to correct.
BCS needs to be correct for months ahead of calving – cows with a BCS too low or too high need to be closely monitored.
These cows are more prone to issues at calving and post-calving and are often referred to as problem cows.