Low dry cow condition scores risk production loss

Analysis of the data from TMS from 361,000 cow records has shown that low body condition score has the potential to reduce milk yield at first recording. The graph below shows the relationship between dry cow body condition score and first test milk and shows an improvement of 3.8kg daily milk yield for a dry cow BCS of 3.5 compared to a BCS of 2.5.

Dry body condition & milk yield (kg)

This has recently been confirmed by work from the University of Florida. The paper in the Journal of Dairy Science looked at the effect of prepartum body condition score on pre and postpartum dry matter intake and milk yield over the first 28 days for 427 multiparous cows. (Casaro S et al., J. Dairy Sci 2024).

The classification of body condition prepartum was chosen as:

• Fat BCS >=4.0
• Moderate 3.25-3.75
• Thin <= 3.0

While the Thin group cows had the highest DMI pre and post partum based on DMI as % bodyweight, that group produced less milk than the Moderate BCS cows such that the latter produced 6.0kg milk more per day for the 28 day period post-calving. For reference, the average DMI kg pre-calving was 9.97kg, 11.15kg and 11.92kg for Fat, Moderate and Thin groups of cows respectively. 

Fat group cows had the lowest pre and post-calving dry matter intakes and moving from a BCS of 3.5 to 4.5 was associated with 4.4kg less milk per day for the first 28 days of the lactation.

 So, there is a risk of cows not hitting peak milk at 4 weeks if body condition is either too thin or too fat, equating to up to 6kg/cow/day.

To try to reduce this impact we would suggest:

1. Body condition score cows at drying off and monitor through the dry period.
2. Ensure that the dry cow ration provides sufficient intake of energy and metabolisable protein (MP). The MP is of particular importance since loss of BCS is often a combination of adipose and muscle tissue.
3. Feed space should be targeted at 36 inches to maximise dry matter intake.
4. If straw is being fed, ensure it is clean, mould free and is short chopped, preferably through a straw processor with a 2.54cm screen.
5. Provide clean fresh water with a minimum water trough space of 1m per 10 cows.

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