we use pharmor - AKA rocket fuel - Very good results.
Costs around 80p per tonne.
Others saying no need for an additive. We are beef / sheep, and used to think that we did not need an additive, but our grass swards always had a very high clover content. Silage always seemed to smell sour, and we tried wilting, not wilting, all to no avail. Used to spend a fortune on malasses to try and get the cattle to eat the silage, and were also feeding lots of concentrate to help them to finish.
Since using an additive, we have not bought any molasses, and, have very significantly cut the use of concentrates fed.
Our suckler calves born jan - may were weaned at housing, and only given 1kg mixed barley per head per day for about a month, before cuting this out completely. They are on silage and silage alone, and are growing very well, and are holding their condition. Also the previous years steers and heifers are not having anyt concentrate, only the silage, and all except 4 / 5 of the heifers have been sold fat, and several of the steers. depending on the genteic potential of the cattle, weights of the steers have been between 550kg LW and 725 KG LW - mostly over the 600KG one steer was 550 as out of a small cow by a small lim bull which we have now got rid of. This was done with the animals being sold at 24 months with nothing but grazed grass, and grass silage.
We will not try to make silage without using an additive, and the one which has always seemed to work for us in the pharmor one. £ 800 for 1000 tonnes of silage performing well IMO is a very good insurance policy. How much concentrate will £ 800 buy you ? - not much to compliment 1000 tonnes of silage.
Daniel.