Often a controversial topic of conversation is dropping the amount of meal fed in the diet but, as growth rates take off with growth averaging at around 70kg of dry matter (DM)/ha/day, overfeeding is costly and slowing up the rotation.
At growth rates of 60-70kg of DM/ha/day, farmers need to be getting through the rotation in 20-21 days in order to get back around to a cover of around 1,400kg DM/ha.
Delaying this rotation would mean cows will be grazing the start of the next rotation at heavier covers, which can impact both on the digestibility of the sward and animal intake. This in turn will hit milk yield and protein percentages.
The obvious choice to quicken up the rotation and stay ahead of grass is to take out a paddock for bales, which will help in keeping cows grazing covers of 1,400kg of DM/ha.
As cows graze optimal covers of 1,400kg of DM/ha, the response in kg of milk relative to kg of concentrates fed decreases with more meal added in the cow’s diet, as grass dry matter intakes (DMI) are decreased with more meal in the diet.
When pre-grazing covers are at 2,000kg of DM/ha, DMI is straight away limited and the response in milk yield increases relative to kg of concentrates fed compared to the response from meal at optimal covers due to the poor quality and low digestibility of the heavier cover.
Therefore, an increase in growth rates should allow farmers to address the meal feeding rates, to get more grass in the diet,as excess meal feeding will only displace grass from the diet and impair total diet digestibility, according to Teagasc.
Meal in the diet
If farmers are in a comfortable position with grass and are ensuring that cows are grazing lush covers when the grass is at the three leaf stage, then they should try and decrease meal by 1kg/cow/day and observe the impact on performance.
It takes approximately 0.6-0.7kg of milk to cover the cost of 1kg of concentrate currently, according to Teagasc, which means that at current growth rates, this can be replaced with high quality grass.
Not only will decreasing the amount of meal promote the DMI of your herd, but it will save a nice bit of money and quicken up the rotation leading to optimal cover being grazed, optimal post-grazing heights achieved, and increased animal performance.
Typically, at higher feeding rates of 4-6kg, the meal will displace about 0.5kg of grass DM grass for every 2kg increase in meal fed.
Meal aside, farmers need to make sure they are allocating enough grass to the cows during peak milk production, which can then lead to a smooth transition of meal reduction in the diet.
Mature herds need 19-20kg of grass allocated and – at a high stocking rate of 3.5 cows/ha – a growth of 65-70kg of grass DM/ha/day is required to maintain covers.
Pushing mid-season stocking rate above this threshold will limit the farm’s capacity to produce milk from grass and increase the cost of production, as intakes will begin to depend on meal feeding.
The other drawback in pushing your stocking rate to the limit is that it slims the possibility of reseeding paddocks and does not give an opportunity to take out paddocks for surplus bales.
It is important to keep quality grass in the diet and pre-grazing cover of 1,400kg/DM/ha as, according to Teagasc, every 1% reduction in grass digestibility will reduce milk solids yield by 1.25%.
Remember, to achieve a grass intake of 18kg of DM, farmers need to be allocating about 19-20kg of DM/cow and ensure that cows are grazing to at least 4.5cm in 24-36-hour allocations to support optimal intakes.
