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Body Condition Score (BCS) plays a crucial role in dairy farming in New Zealand. Keep the BCS range as small as possible within your herd to ensure better reproductive performance. The page offers strategies to achieve this and also provides helpful tools and additional resources.
Range in body condition score (BCS) is as important as average BCS at calving on New Zealand dairy farms.
The ideal BCS of 5.0 for mixed age cows and 5.5 for first and second calvers is optimal for each individual animal, as well as a herd target.
The cows at greatest at risk of poor reproductive performance are the first and second calvers. We all know that within a herd there is always going to be a range of BCS, as each animal will have a slightly different metabolism, intake, milk production etc.
The challenge is to get the spread in BCS at calving as small as possible around the targets. There are a number of strategies to achieve this:
These cows put fat on their back instead of milk in your vat. When feed is short, herd milk production commonly increases by drying-off the low producing fat cows as the other more productive cows are fed better. In addition there is often an area of low quality feed on the farm where these cows can be put to maintain themselves, such as steep sidelings or gullies.
Check every four to six weeks that replacements are gaining enough weight and remedy any shortcomings. Aim to have these at BCS 5.5 when they return from grazing, as they will put little weight on (and often lose weight) while they adapt to being in the herd. Well grown heifers introduced to the mixed age cows during the dry period will compete well as milkers.
Young cows are still growing to reach their mature weight and often have lower intakes. Therefore, they are only able to put weight on slowly, and require more time to get to target condition.
If you dry-off all at once then it is necessary to split the dry cows into herds based on condition and expected calving date. This allows for preferential feeding to get all cows to target BCS. Even if not enough feed is available to put on extra condition, creating herds is still a good idea, as it protects the younger cows from competition from the older more dominant cows. If supplement is going to be fed then feed it to the herd you want to gain the most condition or that needs to put it on fastest.
The principle here is that every dry cow can be fed the same, but the difference is how long she is dry for. In low input systems, the dry-off decision rules (DairyNZ Facts and Figures Book, pg 38) work well. In higher input systems, where dry cows are well fed on a mixture of pasture and supplement, cows that are BCS 4.5 or better only require 50-60 days dry; cows that are BCS 4.0 or below need around 80-90 days dry.
Use the tool below to calculate dry-off date to reach BCS targets at calving.
Cows that are milked OAD are less likely to milk off their back than cows milked twice-a-day and when well fed, will put more weight on during lactation. Groups of cows that are particularly vulnerable to not reaching BCS targets, such as first calvers and early calving cows, are ideal candidates for partseason OAD milking.
The key is to go on OAD early enough to have an impact on BCS, as milking OAD for a couple of weeks or a month before drying-off has little impact. The reduction in daily milksolids production can largely be made up by milking on for longer, as cows do not have to be dried-off as early due to BCS. OAD milking is unwise where the herd already has a high SCC, as it will increase when starting OAD.
Find out how Canterbury farmer Greg Roadley uses body condition scoring in the video below.