Wet weather has really put a spanner in the works on many dairy farms. Cow production has typically dropped by 0.2 to 0.3 kg MS/cow/day, silage making has been near impossible, cow cycling is less obvious and farmers can’t get onto the land to cultivate crops. So what are the options right now?
Feeding the herd
Wet conditions have meant less energy is available to cows – the main reason for lower production. They’re eating less pasture even though there is generally plenty there (less grazing time and more wastage) and while the pasture quality is still quite good (12MJ ME/kg DM) the DM% is lower than usual at 12% - 13% compared to a normal October of 14% - 15%.
So, the common comment of “there’s no guts in the grass” only applies to the lower DM% not the quality of that DM. Probably the key factor is they just aren’t eating enough of it.
Don’t beat yourself up trying to stick to ideal grazing residuals in these extreme conditions. This is a time when you can, and probably should, deviate from text book decisions around grazing residuals and supplement use.
Many farms have paddocks that are too long for grazing, and some that have passed the ideal stage for making good silage with a speedy recovery. Fortunately, the time of year means speeding up the rotation temporarily is okay. An 18-20 day rotation means ryegrasses should have returned to the two leaf stage and have sufficient energy reserves to recover from yet another grazing.
When the weather improves, move to a longer rotation, get the silage harvested and restore grazing residuals to the target. If higher residuals resulting from this wet spell are not dealt with during the next rotation, poorer quality and open pastures will develop with the onset of reproductive stem growth, and with less light to the base of pastures for daughter tiller survival.
Periods of very wet weather can have an effect on mating. Firstly, cows have less obvious heats which are more difficult to pick up, and secondly, underfeeding will mean weight loss at a time when we like to see cows gain weight.
Having said that, we know from previous trials that dairy cows are pretty resilient at the critical time of mating, provided they were in good condition initially.
Supplement or OAD use
Even though the payout is still not great, supplement use may be justified at this time of year due to potential underfeeding from the wet conditions. Once-a-day milking is another way farmers are responding. Do the sums, or take advice.
At a $5 milk price, supplement such as PKE, landed on farm for around $250/t, is break even if conditions are dry and grazing residuals are around 1,450 kg DM/ha. How does that relate to wet weather residuals? Not easily.
You probably have a sense of how well the cows are being fed relative to dry weather. It’s possible 1,400 – 1,500 residuals in dry weather relates more to 1,800 – 2,000 in very wet weather. You’ll have to make a judgement call and this is where the art of management comes into play, which includes pulling supplement out again as soon as it is not required. A decision might have to be made without perfect information.
Knowing your cows are not significantly underfed can be a reason in itself during these extreme conditions.
Here is an example of what consulting officers are observing out in the field, due to wet weather.
A 480kg average liveweight herd doing 1.6kg MS/day with 3kg PKE/day will only be eating about 12kg DM of pasture. For a farm with 2.8 cows/ha on a 21 day round, entering into 2600 cover, this means the residual is going to be about 1900kgDM/ha. Visually it looks more like 1700-1800, however there is grass buried in the mud that we are not seeing. This is what is giving the impression that the grass doesn’t have any guts to it.
Look after yourself, as well as your pasture and your cows! This challenging period will hopefully be a short one.
DairyNZ's wet weather management page has more information on dealing with extremely wet weather. Most of this is relevant for all seasons.