Silage Insights - Trends and Developments
Issues and opportunities in bale silage production in Poland

By Dr. Barbara Wróbel and Dr. Halina Jankowska-Huflej Researchers at the Institute for Land Reclamation and Grassland Farming at Falenty, Poland

The winter season in Poland lasts about six months, thus it is essential to produce and preserve large amounts of roughage. The technology of harvesting and preserving meadow swards using the traditional methods of drying the crop on the field remains popular in Poland, due to a lack of history and culture in crop ensiling, as well as other factors such as the absence of appropriate equipment especially in smaller farms, the costs of stretch bale wrap film used to bale the crop and from farmers’ lack of knowledge of this farming practice.

For the majority of the 20^th century, the Institute for Land Reclamation and Grassland Farming had been implementing plans targeting at educating farmers to shift from hay production to silage production. The measurable benefits that farmers can obtain from this shift are different: silage offers limited nutritional losses, higher nutritional value and higher intake and output efficiencies from animals.

Table 1. Nutritional value of hay and silage (Zastawny, Paluch, 1996)
Specification	Hay	Silage
Dry matter DM (g kg -1)	842.4	501.8
Crude protein (g kg -1)	139.4	175.1
Crude fibre (g kg -1)	294.6	272.7
Crude ash (g kg -1)	88.5	104.0
Crude fat (g kg -1)	20.1	25.0
Nitrogen-free extracts (g kg -1)	457.4	423.7
Energy NEL (MJ kg-1 DM)	6.39	6.29
Daily intake of feed (kg DM per head)	5.80	6.54
Daily gains of heifers (kg per head)	0.575	0.646
Source: Institute for Land Reclamation and Grassland Farming

As a result, ensiling is becoming increasingly popular in Poland, especially among dairy farmers and breeders. Currently, almost 12 percent of yields from permanent meadows are ensilaged, while in 2000 it was only just few percentage points. Despite big round bales are being considered more expensive in comparison to clamps or silos, farmers seem to appreciate its simpler production process.

However, the silage quality produced today in Poland is often poor as a result of a series of mistakes that farmers tend to make during the harvesting, ensiling and feeding stages. As a result, in the past few years, the Institute has paid particular attention to the transfer of knowledge about silage baling technology and best practices through visual aids, informational materials and conferences.

A key element for producing quality silage is the correct timing of harvesting (Table 2). Polish farmers often tend to mow meadows too late, in the full heading phase and sometimes during the blooming stage, aiming for quantity rather then quality.

Table 2. Influence of term of harvest alfalfa-grass mixture in the 1st cut on nutrition and energetic value (DLG)
Harvest in phase of alfalfa development	Content in 1 kg of dry matter
	total protein (g)	crude fibre (g)	crude ash (g)	crude fat (g)	nitrogen-free extracts (g)	Net energy for lactation (MJ)
Before budding	240	191	123	74	372	6.44
Budding	193	238	106	68	395	6.13
Beginning of flowering	154	272	102	35	437	5.82
Middle to end of Flowering	149	309	104	35	403	5.29
After flowering	126	354	95	31	394	5.10
Source: Institute for Land Reclamation and Grassland Farming

A second key element is achieving an appropriate dry matter content level. In the case of meadow sward ensilaged in big bales, it should ideally be 35-40%. Polish farmers tend to ensilage when the DM content is often too moist leading to higher effluent production and leakages in the environment. It is recommended that chopping with rotary mowers with conditioners, significantly speeds up the drying process of mown green forage.

A third key element to take into account for producing quality silage is the length of pre-wilting of mown meadow sward on the swath. When the material is too dry, it influences the quality of silage and increases the risk of mould formation. Pre-wilting of meadow sward (often unsuitable) does not always equate to a good quality of silage.

Polish farmers are increasingly recommended to use additives in their silage production. Biological additives are used in Poland often in the form of bacterial inoculants containing lactic acid bacteria and enzymes, which facilitate the ensiling process and limit the development of secondary fermentation. It is especially important in yearly feeding of animals with silage. However it should be noted that silage additives will correct mistakes made during the harvesting and ensiling process (i.e. soil contamination, improper chopping, bale compression or silos covering). The use of additives is advisable when the principal conditions of fermentation have been achieved. Additives do not substitute the fermentation process, but certainly encourage it.

When making bale silage, factors that often farmers do not sufficiently take into consideration are the bale wrapping procedure, the use of quality silage stretch film, the use of sufficient number of film layers on the bales, as well as proper storage to ensure protection against film damages.

It is crucial to continue the education work about silage production in Poland. Despite the considerable progress in this field, silage is less developed in Poland compared to other EU countries. It is essential as good silage is a basic standard value, the cheapest fodder in winter and increasingly used in the yearly feeding of ruminants. Hence, the future educational activities of Institute for Land Reclamation and Grassland Farming must be multidirectional. Aspects related to environment protection should be taken into account alongside the technological aspects of silage production, such as silage wrap film collection and recycling, health aspects of animals fed with silages (eg. the presence of mycotoxins in silages and other toxic chemical compounds), and the quality of milk and other end-products (e.g. presence of aflatoxins or bacterial spores that deteriorate the nutritional value of milk for the processing and production of cheese).

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