Using the dry period to set you up for a successful lactation

Kyabram-based vet Katrina Martin.

It’s that time of year everyone looks forwards to — drying off. Less cows in the dairy, shortened milking times and fewer hungry mouths to feed.

While a lot of farmers are well versed in the dry-off process and are happy to see their milking herd size temporarily reduced, dry cows are often a management group that can be forgotten.

Although we would like to ‘set and forget’, appropriate nutritional management cannot only help with the transition period but can also greatly affect the production efficiency for the next lactation.

For most cows the dry period is generally about eight weeks long. During the dry period, the milk producing cells in the udder have the opportunity to regenerate before beginning another lactation.

To ensure an adequate dry period, an accurate estimation of the calving date needs to be known.

The use of early pregnancy testing (between six to 16 weeks of gestation) allows for the best possible estimation of conception date and therefore calving date so that an appropriate dry period can be determined.

Early pregnancy testing also allows early identification of empty cows or those with specific problems so that strategic management decisions can be made. For example, cows detected in calf with twins can be dried off earlier as they frequently calve before their estimated calving date.

Cows should ideally be dried off with a body condition score (BCS) between 4.5 and 5.5 (one to eight scale).

Body condition scoring at dry-off allows the diet to be adjusted so that cows go on to calve in the desired body condition.

You should aim for cows to not lose or gain more than 0.5 BCS between drying off and calving to prevent them from becoming over-fat or mobilising excessive body tissue.

Cows with a BCS greater than 5.5/8 (target less than 15 per cent of the herd) at drying off should be fed to maintain condition during the dry period — it is important not to allow over-conditioned cows to lose condition during this time.

Over-conditioned cows or those who gain weight during the dry period, typically consume less dry matter prior to and after calving.

This can increase the risk of metabolic problems around calving and have a negative impact on subsequent milk production and reproductive performance.

Cows with a BCS of less than 4.5/8 (target less than 15 per cent of the herd) should be preferentially fed to increase feed intake during the dry period.

These low BCS cows or those who lose condition during this period, mobilise fat reserves prior to calving leading to increased risk of periparturient problems.

The benefits of appropriate body condition at drying off and calving extend beyond subsequent milk production.

Cows that calve with a BCS 4.5–5.5/8 can have six-week or 100-day in-calf rate at least 12 per cent higher than if they had calved at a BCS below 4.5 (Cow Body Condition Scoring Handbook, Dairy Australia, 2013).

If you require advice on body condition scoring or management of cows at drying off, speak with your herd vet or nutritionist.

Katrina Martin began her career in south-west Victoria before heading closer to home at Kyabram. She enjoys all aspects of dairy work but especially enjoys engaging with farmers to help make their business more profitable through improved herd health. Katrina says she is keen to learn about more aspects of dairy, in areas not just related to veterinary health, to better understand how these businesses run.