36 CONTROL BULLETIN NO. 148 



So far as sugar refining is concerned beet pulp is refuse, and citrus pulp is 

 refuse to the concentrated and frozen fruit juice industry. Likewise, distillers' 

 and brewers' grains are refuse from the viewpoint of alcohol manufacture. These 

 grains were actually discarded as worthless at one time. Yet we do not have 

 dried refuse distillers' grains or dried refuse beet pulp. 



In our examination of the screenings samples we found a considerable number 

 that contained over 60 percent weed seeds. Under the tentative definitions these 

 samples would be labelled "refuse screenings." 



In most cases the weed seeds were mainly foxtail seeds, although some samples 

 contained up to 30 percent mustard seeds. According to Morrison, we have the 

 following data for foxtail seeds in comparison to those for oats: 



Digestible 

 Protein Protein Fat Fiber T.D.N. 



FoxtaU 12.1 8.6 4.1 8.6 75.7 



Oats 12.0 9.4 4.6 11.0 70.1 



Apparently there is no question regarding the feeding value of foxtail seeds. 



There has been a rather general belief that mustard seeds are injurious. J. O. 

 Tretsven and J. A. Nelson of the Montana Experiment Station in Bulletin 435 

 (1946) report that ground yellow mustard seed (Brassica arvensis) has a feeding 

 value slightly higher than that of soy bean oil meal at an 8 percent level. It 

 was found that fanweed or stinkweed seeds ( Thlaspi arveiue) have a feeding value 

 equal to that of soy bean oil meal at the 8 percent level. 



When 10 percent ground yellow mustard seed was substituted for equal 

 amounts of ground barley in the concentrate, cows produced 100 pounds of milk 

 on less concentrate. No objectionable effect on the flavor of milk was noticed. 

 The cows ate readily a concentrate containing mustard seed up to 16 per cent. 

 No detrimental effect on flavor of milk, cream or butter was noticed when 8 per- 

 cent of fanweed seed was fed. 



The analysis of the mustard and fanweed seed used is: 



Protein Fat Fiber 



Wild mustard seed 23.4 30.2 11.0 



Fanweed seed 11.1 24.6 17.3 



Morrison lists the total digestible nutrients as 90.8 percent for wild yellow 

 mustard seed. 



^^ Millions of tons of screenings have been fed to livestock in this country. A 

 great deal of the tonnage contained over 10 percent mustard seed. There have 

 been no detrimental effects reported to this Control Service either on the health 

 of animals, quality of the milk, or on mUk production because of the mustard 

 seed content of screenings. 



Therefore, it seems logical to conclude that screenings containing large amounts 

 of weed seeds, if ground finely enough or otherwise treated to destroy seed via- 

 bility, and properly labelled, have an important place in the feeding program 

 of the country. 



