Buffer feeding is a useful tool if need to fill severe reductions in grass supply but should be avoided when grass is in good supply..
DairyCo senior technical extension officer Piers Badnell warns buffer feeding is only be considered if you need to fill severe reductions in grass supply.
He says buffer feeding with forage or Brewers Grains is only necessary when there is a grass deficit of more than 2-3kg a head.
He explains: “Buffer feeding has two drawbacks when grass is available. First, it teaches the cow to be a poor grazer, as she knows there is a full trough waiting for her, so she selectively grazes.”
Mr Badnell says selective grazing exacerbates the situation by reducing grass aftermath quality and growth.
“Because the cow does not graze aggressively she doesn’t hit residuals required. The result of this is reduced quality and growth in subsequent rounds.”
Buffer feeding also increases rejection sites caused by manure.
“Dung from a buffer-fed cow is far more coarse and takes ages to break down, thus increasing rejection sites.
“Grass dung is far looser and spreads further, providing a larger surface area for bugs to break it down.”
Good grass management
Instead, Mr Badnell says shortfalls in grass can be avoided by managing grass well.
“Well-managed, rotational grazing massively reduces the risk. Introducing silage aftermaths into the round can alleviate a slowing of grass growth.
“In addition, good grazing will lead to better plant and root health, thus aiding grass output and, if you slow the round early enough as grass is reducing and enable grass to reach its third lead, you will have more grass available.”
Where buffer feeding is required the best time to feed cows is pre-afternoon milking so they don’t go out with a full belly, Mr Badnell says.
He says milking also triggers a hormonal response to eat and drink.
Supplementary feeding in the parlour
Concentrate feeding in the parlour is adequate to make up for smaller shortfalls in grass up to 2kg/DM rather than costly buffer feeding, says Mr Badnell.
Hefin Richards from Profeed Nutirtion says the most important objective for most herds this season is to balance rations to maintain cow health and protect fertility.
“A lot of people are now on A to B contracts so the last litres they produce are at a very low price, so it may not be economical to push for the last litre of extra milk.
“Instead, the important thing is try to hold body condition and keep fertility on track throughout the grazing season.”
He says producers need to have a clear target based on grass intake and availability in order to allocate the appropriate level of supplementary feed at the feed fence and in the parlour.
“It is really about looking at the farm individually and taking into account the whole diet.
“The key thing to avoid is overfeeding protein. If you’re feeding in the parlour you should be moving to lower protein products, because the grass is likely to be quite high in protein and feeding excess protein will just drive short term milk yield at the expense of body condition and fertility.
“Keep an eye on starch levels, and monitor rumen fill and rumination (cudding) activity – acidosis is a real risk on high-quality grass and excessive levels of starchy parlour feed.
“If you’re feeding 4kg-plus in a meal, you will be getting a big substitution effect [whereby cows will eat less grass], particularly if that feed is not rumen-friendly.”
Instead, farmers should be feeding moderate amounts of products with high levels of digestible fibre and slow release starch energy that are no higher than 16% protein, Mr Richards advises.
“Protein drives milk production, but has a negative effect on body condition. If the cow isn’t getting enough energy, but a lot of protein, she will give a lot of milk for a short time but she will mobilise fat and lose condition, which will impact negatively on output and efficiency in the months to come.”
How to calculate energy requirements
Step one: A Holstein/Friesian cow requires 10% of her bodyweight plus 10 MJ of ME a day for maintenance eg 600 x 100 = 6 x 10 = 60 + 10 = 70 MJ ME
Step two: 5.3 MJ ME is required to produce one litre of milk at 4% fat and 3.3% protein
Step three: If a cow eats 14kg of grass at 12ME that will provide her with 168MJ ME (14 x 12 = 168)
Step four: When you take away the maintenance she will be left with 98MJ ME (168-70 =98)
Step five: She will be able to produce 18.5 litres of milk (98mj/5.3mj =18.5)
Step six: But she is required to produce 30 litres so there is a shortfall of 12.5 litres (30-18.5=12.5)
Step seven: 12.5 litres x 5.3mj = 66MJ
Step eight: Additional feed required is: 5.5kg of concentrate x 12ME = 66MJ