Bulls: As most farmers are now past or about to pass the three-week mark of breeding, it’s important to take stock of where the herd is at.

What is the story with cows not yet served? Some are probably not calved long enough to have had a cycle, while more will need to be scanned to see what the issue is. If they are thin, consider putting them on once-a-day milking.

Most farmers will be letting bulls off with the herd over the coming weeks.

The general rule of thumb is that one mature bull (more than 24 months of age) can serve 20 to 30 open cows while younger bulls should not be asked to serve any more cows than their age in months. So an 18-month-old bull shouldn’t be asked to serve more than 18 cows. Somewhere between 30% and 40% of cows should still be awaiting pregnancy after six weeks of breeding. This will vary depending on how fertile the herd is and submission rates in the first six weeks.

So in a very fertile 100-cow herd, if 70% are in calf after six weeks, there will be 30 open cows on the farm. It’s a tall ask for one bull to manage this regardless of his age. What if two or three cows come bulling on the one day? Bulls can get lame, be off form or experience transient infertility. Having a minimum of two bulls overcomes most of these issues. Regardless of herd size it’s a big risk to just have one bull. In larger herds with long walks, consider bull teams, so bulls get a rest period. Try and avoid bringing bulls into the collecting yard if possible. Get bulls fertility tested prior to use.

Fertiliser: With milder weather, grass growth rates have increased but as we can see on this week’s Grass+ page, growth rates are still well below normal. A further lift in temperatures is forecast for next week so this should help to increase growth rates. Grazing cleanouts have suffered in the past week due to wet weather. It also appears that cows aren’t that content grazing low covers of low dry matter, lush grass that is possibly high in nitrogen. Because grass growth rates have been poor for the past six weeks or so, a lot of the nitrogen that was applied and not utilised will still be available to the plant.

So while most farms are still on the edge when it comes to grass supply, try and avoid the temptation to spread extra nitrogen to try and make the grass grow, because in all probability there is enough nitrogen in the soil.

Remember, nitrogen is like an accelerator in a car – it’ll make grass grow faster. I’d say following the cows with between 15 and 20 units/acre of nitrogen after grazing on a 21-day round length is plenty. Where there is a good bit of clover in the sward, go on the lower rate or skip every second round of fertiliser.

Calves: It has been a tough few weeks for young calves out at grass. Monitor calves closely for signs of chill or ill health. It’s too early to be dosing for worms just yet. Let them build up some immunity before dosing. Keep feeding meal until weather settles and if grass is very lush, give them access to straw.