Dec. 1894,] 



GENERAL AGRICULTURAL NOTES.- 



227 



Potatoes as Fodder for Milch Cows. 



There has recently been published ia the " Comptes Renclus 

 de VAcademie des Sciences," an account of researches conducted 

 last winter hy M. Charles Cornevin, at the suggestion of M. 

 Aime Girard, with a view to determine the effect of a potato diet 

 ou milch cows. It appears that when deprived of all other 

 nutriment, milch cows will consume a daily quantity of potatoes — 

 fed raw, suitably chopped up, and ad libitmn~equ^ to 7 per 

 cent, of their live weight. M. Cornevin finds that whilst this 

 exclusive diet produces an increased flow of milk, it causes a 

 considerable diminution in the live weight, and these changes 

 are as distinct as they are remarkable. The excreta of the 

 animals are relaxed and whitish, containing undigested starchy 

 matter. No sugar is found in the urine. 



Cooked potatoes are eaten readily enough by cattle ; but, when 

 these form the only food, rumination is either interrupted or ceases 

 altogether, and the digestion is imperfect, so that the diet cannot 

 be continued. According to M. Cornevin, potatoes, whether raw 

 or cooked, must be mixed with other fodder so as to make a suitable 

 ration for the production of both milk and meat. Such a mixture 

 favours the mechanical and chemical processes of digestion, and 

 raises the co-efficient of digestibility by making the nutritive . . 

 ratio more in accord with the food requirements. 



By a parallel series of experiments upon two lots of milch 

 cows, one receiving a ration in which potatoes constituted 50 per 

 cent., the other a ration in which they constituted only 22 per 

 cent, of its total dry weight ; M. Cornevin found the former 

 ration to be clearly preferable to the latter. By means of other 

 comparative experiments he further proved that, when supplied 

 in equal quantities, raw potatoes favour the production of milk, 

 while cooked potatoes promote fattening and increase the live 

 weight. 



Under the influence of a diet of which cooked potatoes forms 

 the basis, the proportion of milk-sugar increases, but this increase 

 ceases upon a change of food. By analysing each week during 

 nearly four months, the milk obtained from eight cows fed upon 

 a ration of 44 lbs. in one case, and in the other of 22 lbs. of 

 potatoes, the following modifications were found to be constants 

 There was a diminution in the specific gravity of the milk in 

 the proportions of dry matter and casein ; but there was an 

 increase of butter fat and also of mineral matters. 



As regards the quantity of potatoes to be used as fodder for^ 

 milch cows, M. Cornevin states that this must depend upon the 

 object in view as regards the milk, whether it is to be sold 

 in its raw state, or whether it is to be made into butter or 

 cheese. 



