Maximising milk from grass is critical to maintaining summer margins for most grazing herds.
Yet failing to compensate for the steady drop-off in grass intakes as summer progresses will put winter production under threat, says KW nutritionist Dr Anna Sutcliffe.
According to figures from Trouw Nutrition, regaining 0.5 body condition score (BCS) lost during late summer can cut daily milk output by 1.9 litres/cow for the first three months of winter, as cows prioritise replenishing lost condition once fully housed.
For a 200-cow herd, that equates to a loss of about £8,900, even at 26ppl.
Dr Sutcliffe says: “The alternative, providing the additional energy needed for those cows to retain that condition, can cost as little as £2,500, based on two months feeding 2.25kg freshweight/cow/ day of wheat-gluten moist feed.
“Just make sure you choose good value feeds, as simply feeding additional compound instead would cost about 30-40 per cent more, plus increase the risk of acidosis.”
Additional autumn feeding should be seen as an investment in winter production, not a cost to be cut, starting as soon as grass dry matter intake (DMI) starts to drop in early July due to the reduction in daylight hours limiting grazing activity.
“In July and August, grazing quality will still be high, at 18-22 per cent DM, 11.5–12MJ ME/kg DM and 20-25 per cent crude protein,” Dr Sutcliffe says.
“But not only is maximum potential intake restricted by falling daylight hours, but consistently achieving that maximum also becomes increasingly difficult as the weather deteriorates.
“Make the most of low-cost summer grazing by fully utilising it for those cows over 150 days in-milk, aiming to maintain yield while controlling BCS in order to dry off at BCS 3.0, rather than 3.5 or more.
“Just do not overestimate the value of grazing for higher yielders.
“Daily DMI typically falls by half between late May and mid-September, at which point it will be supporting little more than maintenance plus five or six litres/cow.
“Remember that any of the seasonal calving herds focusing on maximising milk from grazing will have been in-milk for 150-200 days by mid-August, so the declining potential yield from grass alone closely fits the cows’ falling lactation curve.”
Any cow producing more than this will either need additional feed, or will draw on body reserves to make up the shortfall.
If high yielders fall below BCS 2.5, there can be knock-on effects for milk production, fertility and health in the months before Christmas.
“Ideally, split the herd from August onwards so that high yielders can be supplemented separately and kept in overnight if necessary,” she says.
“Ration palatability is important to help maintain intakes, so include a moist feed, such as wheat-gluten moist feed or brewers grains, or a liquid feed.
“Digestible fibre helps support rumen function to reduce the risk of acidosis and maintain milk butterfat content, particularly if there is a flush of grass in late summer, so consider using sugar beet feed or soya hulls.
“Where starch energy is needed, sodawheat is a more rumen-friendly option than cereals, or make the most of the value offered by co-products like processed bread or the various confectionery blends.”
Feed only good quality forages, including a cereal or maize silage if possible, and for the additional high quality protein needed to support high yields, Dr Sutcliffe recommends using heat-treated rapeseed expeller as a significantly better value source of rumen-bypass protein than hi-pro soyabean meal.
“Aim to set up both the cows and the feeding system ready for winter housing,” she says.
“So rather than feeding an extra 5-6kg of concentrate in the parlour, add 4kg to the buffer ration and feed just 1-2kg during milking.
“It is not only better for the bottom line, but it is also better for the cow and that will translate into more milk and an even better margin over feed costs.”