BCS loss in early lactation


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Loss of BCS in early lactation Factors that affect BCS loss Energy and nutrients

Body condition loss in early lactation is a crucial issue for your herd's wellbeing. After calving, a cow produces more milk than it can eat to sustain BSC, 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 BCS loss, with modern cows often prioritising milk production over body reserves. This page also provides tools for calculating your herd's nutrient needs.

Managing body condition loss in early lactation is critical. Understanding energy and nutrient requirements of cows is crucial to preparing your herd for mating.

Loss of BCS in early lactation

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.

Relationship between milk yield, dry matter intake and body condition loss during early lactation

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 alter the point at which BCS loss ceases (nadir), and the rate of BCS gain after this point.

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 (p48-49) for information on how to calculate your herd's requirements.
  • Alternatively, automatically calculate your herd's requirements with DairyNZ's FeedChecker.
Last updated: Sep 2023

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