BCS loss in early lactation
Topics
1 min read
Body condition loss in early lactation can significantly reduce your herd's wellbeing, productivity, and limit reproductive success. After calving, a cow needs more energy to produce milk than she can eat to sustain body condition, resulting in body reserves like stored fat being used for milk production. This is most noticeable in the first ten days post-calving. Cow genetics and pre-calving BCS heavily influence this loss, with modern cows often prioritising milk production over body reserves.
Loss of BCS in early lactation
Managing body condition loss in early lactation is critical. Understanding energy and nutrient requirements of cows is crucial to preparing your herd for mating.
In early lactation, a cow does not reach peak intake until 10-12 weeks after calving, whereas peak milk production occurs 6-8 weeks after calving.
To provide the energy necessary for milk production in early lactation, a cow mobilises large amounts of body tissue (primarily fat, with small amounts of protein), which is reflected in a loss of body condition.
The greatest loss in body condition occurs in the first ten days after calving where cows can lose up to 0.5 BCS units. They continue to mobilise body reserves for approximately 8-10 weeks after calving, or until the point at which energy intake matches energy output.
Factors that affect BCS loss
Although increasing cow intake or reducing milking frequency post-calving takes several weeks before it has an effect on BCS, these management strategies can advance the point at which BCS loss ceases (nadir). Read more about different strategies for improving Body Condition Score.
Cow genetics and BCS at calving have a stronger influence on BCS loss post-calving than nutrition or milking frequency during this period. The modern-day dairy cow is genetically predisposed to produce milk at the expense of body reserves during this period. In some cows, this can mean that 2-3 kg per day of body reserves are mobilised post-calving to support milk production.
Ideally, a cow should lose no more than 1 BCS unit from calving through to mating, with the aim to have all cows past the lowest point of energy balance and at a minimum BCS of 4.0 at the planned start of mating. This BCS profile will optimise milk production, while ensuring reproduction and animal health are not compromised.
Energy and nutrient requirements for early lactating cows
- See that latest Facts & Figures (p48-51) for information on how to calculate your herd's requirements.
- Alternatively, automatically calculate your herd's requirements with DairyNZ's FeedChecker calculator.