Feeding

Big bale silage can be fed in circular or square feeders to animals in fields or where the accommodation suits this type of feeder. Problems can arise with feeders in slatted accommodation, as silage can be pulled out onto slats. The use of a chopper baler can eliminate this problem. Waste silage should be removed, within two days of the bale being offered. Mouldy silage should be removed from the bale before feeding.

There are various machines on the market that can unroll, chop or split bales for presentation along a feed barrier. The cost of such equipment varies and adds to the cost of an otherwise simple system.

Various experiments have been carried out to compare the feeding value of big bale silage with conventional clamp silage. Work carried out at Greenmount Campus has shown that wrapped big bale silage tends to have a higher DM, pH and ammonia N content than clamp silage, while both forages have similar energy values (Table 5). The higher DM contents within big bales reflect the wilting period which grass undergoes before baling.

Table 5. Chemical composition of convential and big bale silage.

Source: Greenmount Campus

A summary of intake and animal production responses of cattle offered either big bale or clamp silage is given in Table 6. The results show no major differences between big bale and clamp silage in terms of feeding value.

Table 6. Intake and animal performance of cattle offered big bale silage (mean of nine comparisons)

Source: Greenmount Campus

When bale wraps are punctured during transport, by birds/ vermin or when bales remain in the storage area for a prolonged period, air manages to infiltrate the surface layers of the bale leading to a deterioration in silage quality. This is accompanied by mould growths which allow bacteria such as Listeria moncytogenes to flourish. The latter organism is responsible for incidences of listeriosis, which is a disease found among a number of species, particularly sheep. Symptoms include nervous signs, abortions and occasionally septicaemia. Cattle and humans can also be affected. Incidences of listeriosis can be reduced by paying attention to detail when making and feeding big bale silage:

If an additive is to be used, it is essential that the additive is applied evenly and is thoroughly mixed throughout the grass. This is achieved by spraying the additive onto the sward at the point of baling on a number of points across the sward.

When selecting an additive, it is important to purchase one which has been shown to improve animal performance under similar conditions to that being experienced locally. Consultation of the UKASTA forage additive approval scheme will assist in the decision making process. Experimental studies would indicate that use of formic acid under difficult ensiling conditions, will improve animal production. The application of an effective inoculant, under a range of conditions, will also improve animal production. There is little evidence to show that additives which are based on enzymes, molasses or sulphuric acid will improve animal performance.

Most chopper balers use a fixed knife chopping mechanism. Fixed knife choppers use a rotor to pull the grass through a fixed bank of knives. The are 11-14 knives giving a chop length of 8.5-11 cm. A flail type mechanism is used to chop grass in the Orkel baler. The chop is similar to that achieved with a single chop harvester. The main advantage of the chopped bale is that it is easier to distribute the silage at feeding, while bale weights can increase by 8-20%. Research has indicated improved intakes and liveweight gains with chopped compared to unchopped bales.

Chopper Baler.

Recent technological developments have resulted in machines that can make square bales. Advantages of this system include a greater rate of output. The bales can be stacked and covered with polythene sheets which can reduce costs. Square bale silage has been shown to have a similar feeding value to round bale silage.

Square Baler.