524 NUTRITION OF FARM ANIMALS 



Defective planning of experiments is doubtless responsible for 

 much of this confusion. In many instances the experimenters have 

 simply added the feed to be tested to a light basal ration, as in the 

 familiar experiments by G. Kiihn l on palmnut meal so frequently 

 referred to. Others, while substituting one feeding stuff for another, 

 have failed to show that the total amount of digestible matter sup- 

 plied was unchanged. In some extensive investigations, for instance, 

 oil meals and similar feeds have been interchanged in amounts supply- 

 ing equal quantities of protein without regard to other ingredients. 

 Under such conditions concordant results could not be expected, and 

 one can but agree with Lemmermann and Linkh that the evidence is 

 inconclusive, while their own experiments, although indicating specific 

 effects for various feeding stuffs, are scarcely more convincing. 



Similar negative evidence is afforded by the extensive feeding 

 trials with dairy herds carried out in Denmark by Fjord, Friis 

 and S torch and which afford the basis for the so-called " feed 

 unit " or Scandinavian system of comparing rations (702). 

 In these trials a variety of feeding stuffs, including many re- 

 puted to have specific effects on milk production, were compared 

 with ordinary farm grains and failed to exert any material 

 influence on the milk secretion other than what may be plausibly 

 explained by the variations in the protein content and the total 

 nutrients of the rations incident to the experimental method. 

 In particular, indications of a specific effect on the production 

 of milk fat are lacking. 



More positive results have been reached, however, in two 

 recent investigations, viz., in a series of investigations by Hansen 

 at the Agricultural Academy Bonn-Poppelsdorf and in a series 

 of cooperative experiments on palmnut meal made under the 

 auspices of the German Agricultural Council. 



619. Hansen's experiments. Hansen's experiments 2 in- 

 cluded nine series on 63 cows, extending over 5 years, in which 

 the various feeding stuffs to be tested were substituted in a 

 comparison ration for others which appeared to be indifferent 

 in this respect. Care was taken to keep the total digestible 

 nutrients in the rations, or after the first 3 years, the estimated 

 net energy values (starch values), unchanged. 



1 Jour. Landw., 22 (1874), 178. 



2 Landw. Jahrb., 35 (1906), 125 ; 35 Ergzbd. Bd. IV, 327 ; 37 (1908), Ergzbd. Bd. 

 Ill, 171 ; 40 (IQII), Ergzbd. Bd. I, 129. 



