Posted 1/13/2021 14:48 (#8748297 - in reply to #8747196) Subject: RE: Two feed test, one feed
Schram Cattle Co - 1/13/2021 07:05
I definitely agree that I should be taking more probes per sample, but the reality is that when I'm doing a lot of different samples, usually battery power for my drill is my limiting factor.
ADF also seems to be 12.5% different, so I'm not sure the TDN formula's the problem. How do you estimate your feed quality from ADF and NDF?
Mine were done on a Friday and sat in a freezer over the weekend while hers were taken on a Monday--any idea as to whether that might change quality like this?
Reviewing your feed tests a few more times - - - - I'm wondering if a large part of the variation is that they are purely NIR.
When you ask for wet chemistry tests (cost more and take longer) there is far less possibility of variance in the ADF and the NDF numbers - - - - because both tests are done using specified chemicals time and processes.
NIR is great if the lab does at least a few of the tests in parallel using wet chemistry and then adjust the NIR readings.
I'm not an expert on this but AIUI that might be 2 or 3 or 4%. Most labs pump out 10s of thousands of tests on NIR with a handful or parallel testing.
That's what I understand anyway - - - - and that's why the variation can get huge.
An ADF change of 12.5% is huge imo - - - DairyOne labs has a neat database - - - - mixed grass legume hay has in their testing somewhat less than 5% variation per standard deviation.
Means that a 12.5% drop is like 2.5 grades lower - - - - that's not a small drop.
Their 'normal range' for TDN in straw is from 43 to 54.5% TDN.