Q: Are skinny cows really skinny?

A: Ensuring that a dry cow reaches the optimal body condition score (BCS) allows for a proper transition into lactation, as she uses body reserves during the transition period and early lactation to counteract the negative energy balance most lactating cows experience.

Often we target a dry cow BCS ranging from 3.25 to 3.75. However, as BSC is a visual assessment of fat cover, this system relies on trained individuals to be consistent in their scoring approach and assess each cow in a repeatable manner. Moreover, BCS tells us nothing about the internal fat stores.

Assessing inter-organ fat provides a total measure of fat stores available to the cow. Using ultrasound, a newer method to determine total body fat stores takes into account the contribution from both back fat and kidney fat. This method uses a 3.5 mHz transducer that scans the animal at the first lumbar vertebra and the 13th rib for assessment of kidney fat depth and approximately 15 cm for the cow’s midline.

Assessment of kidney fat depth via ultrasound showed a strong correlation with carcass kidney fat, indicating it can provide a reliable means to measure a crucial contributor to whole body adipose stores.

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