Winter dairy feeding: how concentrate levels affect milk producers' margins
Dairy farmers are advised to fine-tune winter concentrate rations, since overfeeding raises costs without increasing milk output. Silage quality is central and should be tested as early as possible.
Building the right diet for a winter-milking dairy herd helps protect margins in a year when costs have been high, according to the UK farming news site Agriland. Concentrates are an important part of winter rations, particularly when forage needs to be stretched, but the amount has to be balanced: overfeeding is expensive and adds no extra milk.
Concentrates replace forage
Concentrates act as a substitute. The more of them cows receive, the less forage they eat, and the weaker the response to the concentrate becomes. In effect, relatively cheap forage is swapped for costly concentrate. The diet should be set for the lower-yielding cows, adjusted for silage quality, with higher-yielding cows fed at a higher rate where possible.
Good silage means less concentrate is needed, because there is less of an energy gap to fill. Silage should be tested as soon as possible to establish its nutritional value and work out exactly how much feed the herd requires.
Teagasc recommendations
Teagasc, the Irish agriculture and food research authority, sets concentrate levels according to silage dry matter digestibility (DMD) and milk yield:
- 20 litres a day: 5.5 kg at 65 DMD, 4.0 kg at 70 DMD, 3.0 kg at 75 DMD;
- 25 litres: 8.0 kg, 6.5 kg and 5.5 kg;
- 30 litres: 10.0 kg, 8.5 kg and 7.5 kg;
- 35 litres: 12.5 kg, 11.0 kg and 10.0 kg.
Highly digestible silage increases forage intake, supports milk solids production and benefits rumen function. A typical 600 kg cow needs 7.5 kg of concentrate to produce 30 kg of milk on 75% DMD silage, but 10 kg if the silage is 65% DMD. Each five-unit fall in DMD generally requires 1.0–1.5 kg of extra concentrate.
High-yielding cows need more energy than low-yielding ones, so rations should be adjusted by splitting animals into groups. Poor silage reduces intake and can change the neutral detergent fibre (NDF) level in the diet, meaning additional fibrous feed such as straw will be required.
