Grass growth rates continue

Growth rates are continuing the same trend as last week with some farms getting as high as 90kg/day. Walking paddocks weekly is a must to monitor both grass covers and quality of the covers – some paddocks may not have been cleaned out to the target residual of ‘0’, especially on hilly paddocks where cows all lie on the top of the hill and cleaning out these areas can be difficult, taking these paddocks/areas out as surplus will increase grass quality offered to the herd.

In England this week, I have seen first hand the level of grass wastage on some high input farms. There seems to be so much of a drive for output that input costs aren’t factored into the equation at all.

Over allocating grass to cows will under allocate energy. The basis for grazing down to a residual of 3.5-4cm is that the grass grown in the subsequent rotation will be high quality feed as it will be grown from a clean base. In high-input herds this ethos is dismissed as larger cows ‘cant eat that low’. In fact they can, as demonstrated in the first rotation with cows cleaning out covers fully when no dung pads or urine splashes are present. High-input farms should graze down to 4.5cm residual for the remainder of the grazing season, using surplus bales as a measure to clean up any paddocks that begin to lose quality.

Optimising grass quality and allocating correctly will settle the animals, whereas over allocating grass to cows creates a dirty base in the sward (which unsettles the grazing animals owing to the musty smell/rotting material), this dirty base is being kept alive by the plant and therefore the plant is wasting energy. This, in turn, wastes nitrogen and reduces tonnage of grass grown. Too many farmers test their silage regularly during the winter and balance this with concentrates – but then turn cows out to grass and feed a similar protein ration outdoors. Grass can be an excellent energy source, however badly managed grass will be very low in energy. AFBI Hillsborough carried out research on pre grazing covers in Northern Ireland in recent years and found that the majority of farmers were grazing excessive pre grazing covers, as a result this grass had an average M.E. content of 10.6MJ/kgDM – worse than most silage. This is down to one key factor: management. Thankfully, we can change this. Graze covers between 1,200-1,500kg/ha, ensuring maximum energy offered to the herd and if needs be, top up with a low protein ration. Grass makes up the greatest percentage of the overall diet in summer so we must ensure it is top quality.

The weather is ideal for picking up cows for AI, as stronger heats are evident in good weather. Heat detection is such a high value job owing to the benefits of increasing the six-week in-calf rate. Our last cow calved this week, the first cow that calved in late January has produced just under 3000 litres (225kgMS) more than her already! This is a huge motivation to put as much effort as possible into heat detection and reduce the number of cows calving in weeks eight-12.

Cathal McAleer is a grassland consultant working with individual farmers and facilitating discussion groups throughout Ireland.

087 160 2491 / 0044 7749 531679 cathalmcaleer@hotmail.com

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