Feed Testing Guide

Why feed test?

Animals can graze and survive on many different types of pasture and forage. The aim is to get the best conversion of that feed into milk, meat, or wool. To do this, both the amount of feed and the quality of what’s eaten need to be managed.

Testing pasture and forage is now widely used to check feed quality, and it’s becoming an important tool on New Zealand farms. Test results show how the chemical make-up of a feed relates to what animals need, and how well it will support performance.

Knowing the quality of your feed helps you see if it will meet the needs of your stock. The class of stock and your production goals will guide how much and what quality of feed is required.

How do I sample for feed analysis?

Timing: The best time for all feed quality sampling is as close to feeding as possible. just prior to being feed to stock.

Pasture and Greenfeed Sampling

Walk a random or zig-zag pattern across the paddock taking 15-20 samples of pasture that represents what stock would eat. To get the samples use either clean scissors/shears or hand sample wearing gloves to prevent contamination.
Take the sample at animal grazing height about 5cm from the ground.
Avoid dung areas, water troughs, stock camps, gateways and any area that animals would not graze.
Provide enough sample – we need about 2L/500g which is the size of a sample bag.
Remove all excess air out of the sample bag, this is important as it prevents decomposition and loss of nitrogen and non-structural carbohydrates.

Compound feed/meal

A representative sample of approximately 500g.

Hay Sampling

Make sure that the samples are all from the same cut and paddock. Different paddocks and hay made at different times of the season should be tested separately.
Take a representative sample from the centre of bales, ideally using a corer to ensure a representative sample. Do not take samples from sides or top of bales. With round bales sample towards the middle of the bale.
Aim for 500g of sample – approximately 20 cores.
Seal the bag well and protect from heat. Dry hay samples (~90% DM) are considered fairly stable, but should still be put on overnight courier.

Silage/Baleage Testing

FRESH CUT: Sampling chopped silage prior to it being baled or placed in a pit gives you early information on quality. If packed and stored properly, silage crude protein and fibre remain stable during fermentation. Follow the same testing protocols as below.

ENSILED: Pasture silage should be ensiled for at least 4-6 weeks before sampling. Bales can be tested after 3-4 weeks. Maize silage should be ensiled for at least 1 week.

For the silage pit use a long core sampler take a series of samples from well-spaced points on various areas of the surface. The core will sample a profile through the layers of the pit. Take different samples for first and second cuts if layered one on top of the other in a pit.
Discard the top 100mm of each core before mixing into a composite sample. The final sample should weigh approximately 500g
If the pit is open you can take 10-15 samples from 15-23cm behind the pit face in a “W” pattern. Avoid edges, the top & any mouldy patches if they are not to be fed to animals.
For bales, use the core sampler to sample three-to-four bales per cut located at various locations in the storage stack. Tape up sample holes using the same-coloured tape to avoid spoilage.
Alternatively, sample three-to-four bales per cut by grabbing random hand samples throughout the bale when freshly opened.

Dry Matter Testing

Measuring dry matter before harvest helps with timing and yield estimates and when buying or selling silage it gives a fair basis for pricing value.
Sampling protocols for fresh silage should include sufficient samples to adequately represent the crop – either from the stack before covering or collecing from a number of trucks. After collecting sub-samples, mix up on a clean plastic sheet, quartering until and mixing until 500g is collected.

If you are sampling maize at harvest particularly if you are buying or selling maize silage on a dry weight basis, ARL recommends that you consult with the Maize Forage Trading Code of Practice. The code outlines best practice for weighing, sampling and testing. If maize samples are not being sent overnight on day of collection they need to be frozen.

After taking the sample

Press or squeeze the sample bag to remove as much of the entrapped air as possible, label and seal the bag tightly. Chill samples overnight in the fridge if you are unable to send to the laboratory overnight. Use another layer of tape on the seal or double bag if you think that air can still get in.
Complete the submission form provided and put the samples plus the submission form and send them to ARL immediately (store in a cool place before dispatch, any delay exposes the sample to excess heat and moisture and will affect the analysis)
Samples should be sent to ARL no later than Thursday to ensure they arrive at the lab on a working day. It is better to keep samples in the fridge over the weekend and send overnight on Monday.