Ensuring your cows attain the required pre-calving body condition score (BCS) is an important aspect of building resilience in your herd. Knowing how to assess, identify and improve your cows' BCS will ensure that the benefits of feed grown and herd condition gained up until now are not lost.
In the last several months of gestation, a cow should be fed to maintain her condition as well as to provide for her growing calf. Good planning around drying off and culling is essential, as is regularly checking on feeding levels and BCS — which you can do using the DairyNZ BCS app.
Your main priority is to look after the cows that will be in milk next season. Don't be tempted to milk the cows that are not pregnant for longer, because you believe they'll produce more than their pregnant herd mates. In a six-year study of pregnant and non-pregnant identical twin cows, DairyNZ's principal scientist, John Roche, identified that prior to day 230 of lactation, pregnancy did not affect milk production. In total, pregnant cows only produced 2-3kg milksolids less than non- pregnant cows.
Calving BCS targets are a body condition score of 5.5 for two-year-olds and rising three-year-olds and 5.0 for mature cows.
You can use a variety of strategies to achieve these targets, such as:
* early removal of culls
* early drying off thin cows and low producers
* split herds on age, BCS and 'time until calving'
* stagger drying off based on age, BCS, and 'time until calving'. Remember, rising three-year-olds may still be growing, so some of the feed is going into growth and not into gaining condition
* milking once a day (OAD): approximately 0.25 BCS units' gain over 100 days on OAD milking
* feeding to gain BCS. This may involve purchasing feed.