NRIS Study with Knapweed
Develop fecal NIRS equations for predicting percent spotted knapweed and grass in a sheep’s diet.
A
feeding trial will be conducted for the development of NIRS equations for predicting intake of spotted knapweed
from fecal samples. Twelve mature ewes will be individually fed diets comprised of 4 different sources of spotted
knapweed (4 different growth stages ranging from pre-bud to flowering) and 3 different background forages (alfalfa
hay and two different grass hays) for 3 consecutive 7-day feeding periods. Diets will consist of
- 0% spotted knapweed (period 1),
- 10% spotted knapweed (period 2),
- 50% spotted knapweed (period 3)
- and 50% alfalfa (period 4)
with the remainder of the diet consisting of the appropriate background forage. Fecal samples will be collected on days 5, 6 and 7 of each feeding period. Daily samples (approximately 15 to 20 fecal pellets) will be collected from each sheep daily, either by rectal palpitation or picked up off the floor of a collection pen.
Care
will be used to minimize contamination with urine, feed and dirt if the latter method is utilized. Daily samples
will be dried at 55° C and ground through a 1 mm mesh screen in a sample mill at the end of the three-day
collection period equal aliquot samples will be combined from each of the three daily collections into a final
sample with a total weight of approximately 20g. Samples will be sent to the Texas Experiment Station in San
Angelo, Texas for scanning, calibration development and validation.
