Every year, differences in weather patterns, hybrid selection, disease pressure, time of harvest and stage of maturity along with other variables lead to forage quality that is dramatically different from year to year. This is why it becomes critical to consistently and frequently sample forages on your dairy. The goal with most dairies is to minimize purchased feeds so maximizing homegrown feedstuffs is pivotal, but as a nutritionist I need to know the test results I am working with are accurate. The rations I put on the farm are only as good as the inputted values provided by the lab. Data supports the majority of forage testing variation comes from the sampling procedure and not from inaccuracies at the laboratory when working with a forage certified testing lab. Due to not having enough samples and/or not taking good samples accounts for the vast majority of variation seen which people tend to interpret as “lab error” which in itself is an error. So, before you send another sample to the lab be sure to revisit and/or train feeders on these key forage sampling techniques and methods:
- Safety first! Utilize High Viz clothing so you can be seen and have another person (spotter) with you. If sampling a silage pile or bunker, have it defaced with a loader and moved away from the face. Silage faces can collapse at any time so stay away from them! As an industry we have had to learn the hard way and people have lost their lives from silage face collapses; please don’t let it happen to you. Lastly, observe and understand your surroundings, do not park or stand in high traffic areas of a feeding center.
- The sample needs to be representative of the entire silage face. Nutrient values can vary significantly from top to bottom and side to side of a silage face. That is why it’s so important to deface the entire face of the bunker/pile/bag then comingle the silage into a pile away from the face. Sample what you are actually feeding the milk cows. Take a minimum of 5 handfuls from various spots of the comingled pile and put them into a clean, 5-gallon bucket. It’s important to note that you need to scoop, not grab because corn can easily separate out when sampling corn silage causing a poor sample.
- Make a composite sample. Mix the silage in the bucket by scraping along the bottom and tumbling. The focus here is not to overmix and cause separation. Next, pull a composite sample from the bucket by starting in one spot and working around the outer portion of bucket until you have filled a quart plastic bag ¾ full or you have enough for a koster test. It’s important to work along the outer edge of the bucket because it makes it easier to get a packed hand full of feed. Pack the sample in bag to drive air out to keep it stable for shipment.
- Get the sample to the lab quickly! Deliver the sample to the lab if it’s an option. Most labs offer next day shipping which you should use if you can because fresh samples ensure the most accurate results. If you can’t get the sample to the lab quickly then freeze it before shipping.
If you’re looking to hone-in on a silage’s variability, send two samples by repeating the sampling protocol twice. Do not send two samples from the same collected bucket as this will not help decrease variability. I recommend sending high inclusion ingredients like forages to the lab at least bi-weekly for nutrient values and testing multiple times per week for dry matter using an on-farm Koster tester. When a feedstuff is highly variable and fed at a high inclusion rate, I suggest increasing sampling frequency at a lab to once per week . Another reason for more frequent testing would be when you’re suspicious of a change in the pile and/or cows are telling you something is different.
Highly effective sampling will bring more consistency to your dairy along with reliable results for formulating rations. Hold everyone accountable on the feed team and encourage questions -- your nutritionist should help with this to make it a collaborative effort. Regular check-ins with the feed team is imperative and always remember it’s the little things that can make a big difference.