Use of silage additives in ensiling of whole-crop barley and wheat: a comparison of round big bales and precision chopped silages

Martin Knický & Per Lingvall
Swedish University of Agricultural Sciences (SLU), Department of Animal Nutrition and Management, Kungsängen Research Centre, SE – 753 23 Uppsala. Email: Martin.Knicky@huv.slu.se

Introduction

An increasing use of whole-crop cereals, as supplementary feed, has aroused the task to find an efficient way of preserving those forages to achieve a high hygienic quality. It is known that ensiling of whole-cereals often results in silages with high concentrations of butyric acid (Weissbach & Haacker, 1988). Furthermore, problems with poor aerobic stability still persists despite of the use lactic acid bacteria (Filya et al, 2000). Therefore, the objective of this study was to examine the different types of additive mixtures to improve fermentation process and aerobic stability in precision chopped and baled silages.

Materials and methods

The spring variety of barley and autum variety of wheat were harvested at the dough stage (42% DM). The crops were bailed and wrapped with a 12 layers of stretch film of white colour (width of 750 mm and thickness of 0.025 mm) or chopped to the pacticle size of 2 cm (4.5 l PVC silo). The following silage additives were used: C:control; KU:nitrite, hexamine, Na-benzoate, Na-propionate; P1:42.5%formic acid, 20.5%propionic acid, ammonia; P2:22.4%formic acid, 41%propionic acid, ammonia; LAB1:lactic acid bacteria, saccharose; LAB2: lactic acid bacteria, cellulase, Na-benzoate. The additives were applied at the dose of 4 l/t fresh forage. Each treatment included 3 replicates.

Results

Additive treatments increased fermentation rate in both chopped silages, resulting in a significant pH drop compared with controls (Table 1). Butyric acid concentration was decreased by application of silage additives in both chopped silages as a consequence of restriction of clostridial growth. However, ensiling characteristics of chopped-barley silages were not reflected by aerobic stability in contrast to chopped-wheat silages. Treatments LAB1 and LAB2 increased the fermentation rate in both barley and wheat bales, but only LAB2 silages had an enhanced aerobic stability. Treatments P1 and P2 improved the stability of wheat bales, although pH was significantly lower only in treatment P1. DM losses in all additive treatments were significantly reduced.

Table 1 Ensiling characteristics of barley and wheat silages.

Forage			Treatment						LSD_0.05
			C	KU	LAB1	LAB2	P1	P2
Barley	Silo	pH	5.0	4.5	3.9	4.0	4.3	4.3	0.1
		Butyric acid (%)	2.00	0.03	0.03	0.03	0.03	0.03	0.07
		Stability (Days)	6.5	6.5	1.9	1.1	4.5	2.8	0.8
	Bale	pH	5.1	5.3	4.0	4.3	5.1	5.4	0.3
		Butyric acid (%)	0.05	0.03	0.03	0.03	0.06	0.03	0.02
		Stability (Days)	1.3	4.8	1.2	4.8	1.7	2.2	2.5
Wheat	Silo	pH	4.7	4.4	3.9	3.9	4.1	4.3	0.1
		Butyric acid (%)	1.13	0.03	0.03	0.03	0.03	0.03	0.1
		Stability (Days)	6.5	6.5	6.1	6.5	6.5	6.5	0.5
	Bale	pH	5.1	5.2	4.0	4.0	4.9	5.0	0.2
		Butyric acid (%)	0.03	0.03	0.03	0.03	0.03	0.03	0.02
		Stability (Days)	2.6	4.7	2.3	5.8	6.1	5.6	2.6

Conclusions

Silage additives improved the silage quality more effective in the wheat forage. Bacterial inoculants were most effective in improving silage fermentation, mainly in baled silages, but only LAB2 containing Na-benzoate improved the stability of bales. The application of 4 l/t P1 and P2 was unsatisfactory to improve quality of barley bales. KU seems to be most applicable in both forages regardless type of silage.

References

Filya, I., Ashbell, G., Hen, Y., Weinberg, Z.G., 2000. The effect of bacterial inoculants on the fermentation and aerobic stability of whole crop wheat silage. Anim. Feed Sci. Technol. 88, 39-46.

Weissbach, F., Haacker, K., 1988. On the causes of butyric acid fermentation in silages from whole crop cereals. Zeitschrift das wirtschaftseigene Futter 3, 88-99.

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