EVALUATION OF MEADOWFOAM (Limnanthes alba) MEAL AS A FEEDSTUFF FOR SHEEP
Four experiments were conducted to evaluate meadowfoam meal (MFM) as a protein supplement for sheep. In exp. 1, a digestion trial was conducted with 49-kg wethers to compare raw and steam-cooked (SC) MFM with cottonseed meal (CSM). Apparent digestibility of energy, dry matter and crude protein of the raw MFM diet was reduced (P < 0.01) by 4, 6 and 8%, respectively, compared with CSM. Acid detergent fiber and ash digestibility were greatly reduced by 52 and 55% compared with CSM. Steam cooking caused additional (nonsignificant) reductions of all values except fiber and ash. In exp. 2, a growth trial was conducted with 20-kg wethers comparing diets in which raw MFM replaced 50–100% of the CSM in the control diet. Liveweight gain and feed efficiency were increased at least 20% over CSM at either replacement level. The results suggest that reduced digestibility of fiber and ash protected MFM protein from ruminal degradation, thus allowing larger and more efficient gains. In exp. 3, a finishing trial was conducted with 37-kg wethers comparing MFM and CSM as the supplemental protein source. There were no differences in weight gain, feed efficiency or backfat thickness, but a slight improvement was observed in dressing percentage (P < 0.05) of lambs fed the MFM diet. Histological evaluation of thyroid, liver and kidney showed no specific changes due to MFM feeding. In exp. 4, ewes consumed raw MFM at a level equal to that in exp. 3 during the last 7–9 wk of pregnancy; no differences (P > 0.05) in serum thyroid hormone values were found between treatment and controls. However, two of seven ewes on the MFM diet gave birth to lambs showing signs of goiter. The results of these experiments indicate that raw MFM is a satisfactory protein supplement for growing lambs when used at moderate levels, but should not be fed to pregnant ewes until further research can resolve the problem of goiter development in newborn lambs. Key words: Sheep, meadowfoam, Limnanthes, digestibility