Studies have shown that the gain in milk production by calving cows who are at 5.0 BCS instead of 4.5 was worth about $40 per cow.
Another study also showed that cows calving at BCS 4.0 compared with BCS 5.0 resulted in a 7 per cent less chance to be cycling at planned start of mating (PSM). Cows that have not started cycling at PSM have a 16 per cent lower six-week in-calf rate and a higher empty rate of 6 per cent. And we have certainly seen some poorer reproduction figures this season.
So start with body condition, scoring your herd to get a realistic understanding of the condition of individual cows.
Dairy NZ's booklet Body Condition Scoring Made Easy will help to guide you in condition scoring. The app is also very useful and quick to use.
Targets for when a cow should be dried off will vary, depending on:
•BCS at various dates
•Age of animal
•Date of planned start of calving
•Possible feeding levels and types of feeds.
The table below outlines the number of days a cow requires to be dried off prior to calving to have any chance of gaining the 5.0 and 5.5 BCS targets at calving.
If a cow's calving date is July 20, then the dry-off dates are as follows:
So if a cow's in calving after August 20, then you can add another 30 days to the above dates. This is why individual BCS of cows is important, not just the average of each herd.
By the middle of May you are likely to need all MA cows to be >4.0 BCs and all R3s to be >4.5 BCS to keep milking.
Remember, most cows will need restricted (low metabolisable energy and low protein feed) for 7-10 days to ensure they dry off cleanly. This can reduce BCS further. Maize rates do not need to be reduced through this process as this has low protein at 8-9 per cent CP. But pasture rates will need to be reduced.
Feeding to gain BCS
To gain one BCS above maintenance requirements a Friesian cow will need to eat 160kg dry matter (DM) grass silage, 160kg DM maize silage or 125kg DM of PKE.
The following is the calculation for what a cow needs to be fed to gain 1 BCS.
• A mixed-age cow dried off on May 15, at 4.0 BCS and due to calve on July 20, can only put on weight effectively up to about 3 weeks before calving.
• She has 45 days to gain 1 BCS.
• Maintenance for her through May and June will be about 8kg DM per day.
• To put on 1 BCS with maize, she will need to be consuming about 160kg DM so allow for wastage.
• Plan for 45 days to eat 160kg of extra feed, that's 3.5kg per cow per day.
• The total intake needed calculates to 11.5kg DM per cow per day before wastage. When allowing for wastage, this figure is closer to 13-14kg DM per day.
Feed budget
A feed budget will allow you to calculate how many more days you can milk for – do one from now through to June 1, and another from calving through to your feed balance date.
Ring fence your winter supplements first before deciding what can be fed out this autumn.
The feed budget should include what BCS gains will be required from now to July. Do your feed levels support this? More importantly now in the middle of May, do you have enough days left to hit individual cow BCS targets?
If not, then you need to either secure more supplements, or dry off earlier this season to hit your APC and BCS targets that are so essential when setting up next season.
