Aggregated silage data - last three years | Hill Laboratories - NZ


Aggregated silage data - last three years

Date: 6 Aug 2021
Author: Hill Laboratories

The lab often receives requests for summarised result data, and we know there is high interest in benchmarking and yearly variations for some agricultural tests. We understand the value of large data sets and, as such, from time-to-time we will publish anonymous result data, taking note of any customers who wish their data to be excluded and respecting that position. As this type of exercise requires a considerable amount of data analyst resource to extract and organise,  it currently remains an occasional activity only. We are, therefore, pleased to be able to provide our clients with aggregated silage data for the last three years.

The data shown in Table 1 below is an extract of silage results from the last three seasons, shown as average and range for the main feed quality analytes. The average values from these several thousand samples analysed, align closely with published typical values – but of interest is the considerable range of results seen in the data. This is a very compelling reason to carry out a feed quality test on silage, whether purchased or made on-farm. Having a lab analysis of a silage supply is highly valuable information, in order to suit the available feed to the appropriate livestock class.

Table 1: Average and range values for selected analytes for Silage Samples as analysed at Hill Laboratories since 2018.

Another view of the cereal and maize silage data is shown below in Figure 1, grouped by year. Growing season can have a big impact on silage quality, particularly for cereal and maize where starch production is reliant on summer heat at the right time in the growth cycle. While the average data for each year only shows small differences, there would likely be larger variations depending on local growing conditions e.g. summer drought. Potentially the summer drought in 2019/2020 season can be detected in the average maize silage results even so, with slightly lower digestibility and lower ME for that season.

Silage as a supplementary feed is a valuable resource, to support production goals and to keep animals well fed when grass-growth is low. Achieving good quality silage is not easy, as weather conditions at the time of harvest cannot always be managed. No doubt, the instances of high Ash results (shown in the range column in Table 1) are due to soil contamination or mud being incorporated into the stack at harvest. Soil contamination has the potential to allow listeria colonies to grow in the silage, although this is also dependent on the moisture and acidity levels. As well, Ash does not contribute to metabolisable energy, so soil contamination should be avoided as much as possible.

Fig 1: Maize and cereal silage test results by season for the last 3 season, as extracted from Hill Laboratories database (customer exclusions applied)

Feed testing is made very easy with DIY sampling kits available through your rural advisor or else these can be ordered online. Full sampling instructions, sample bags and a return-paid courier bag are included in the kit. A range of test options are on offer, including a full suite of feed nutrient and mineral analyses together with the fermentation evaluation tests pH, NH4-N and volatile fatty acids important for silages.