18 August 1995

Fibre concs lift milk yield in CEDAR trial

By Sue Rider

FIBRE-BASED concentrates fed as a supplement to maize silage diets will encourage higher forage intakes than starchy concentrates. The higher intake will be reflected in increased milk outputs and milk income worth an extra 30p a cow a day over that from cows offered the starch-based concentrate.

Comments come from Dalgety technical manager Stuart Mars-den. He cites the results of a Dalgety-sponsored trial at the Centre for Dairy Research, Reading University. The work set out to determine the effect of concentrate type on feed intake and milk composition of dairy cows fed a mainly maize silage-based diet.

Early lactation cows were offered ad lib grass and maize silage in a 1:2 dry matter ratio. This forage portion was supplemented with either a fibre or starch-based energy source fed twice daily at 5kg DM a day or 10kg DM a day.

Given the trial results Dr Marsden advises producers seeking to boost milk income to opt for a fibre-based concentrate to supplement maize silage-based rations. And, he says, the higher forage intake (+14%) means that those operating to a quota ceiling can cut cake use but still meet quota.

For producers concerned about quota, and seeking to depress both milk fat content and output, he advises the starch-based concentrate. But he says the benefit is likely to be more evident with parlour-fed as opposed to TMR- fed cattle and when offered at high (10kg DM a day) feed rates.

MILK YIELD

Cows offered 5kg a day of concentrate gave an extra 2.5kg a day of milk when the concentrate was fibre-based. But at high feed rates there was no yield difference bet-ween fibre- or starch cake-fed cows.

MILK FAT

The fibre-based concentrate had no effect on milk fat content in high or low feed regimes. But, as this feed increased forage intake and milk yield, the trend was for overall fat output to rise. The starch-based cake reduced milk fat concentration by as much as 10% as feed rate rose.

MILK PROTEIN

Dr Marsden reports no difference in protein content of milk between the fibre- and starch-based concentrate-fed cows. He reasons that the maize silage produces plenty of starch in the diet to support milk protein production when both types of cake are offered. But, as the fibre-based cake raises forage intakes, the cow would consume more energy, so lifting yield and protein. This was especially so at the low feed rate when protein yield rose 8%. No boost in milk yield, and hence protein yield, was seen when cows were offered the starchy cake or high levels of the fibre-based concentrate.

lDalgety has launched two new compound feeds designed to supplement maize silage-based rations as a result of this research – Maizemaster Hi-starch and Maizemaster HDF. &#42

Cows offered fibre-based concentrate with maize diets will eat more forage and produce more milk than those offered a starch-based concentrate.