318 DAIRY CATTLE AND MILK PRODUCTION 



the soil. If butter or cream is sold, and the skim milk retained 

 on the farm, practically no fertilizing material is removed 

 from the farm, since butter fat has no manurial value. 



It is a fact often lost sight of in practice that the urine of 

 animals contains by far the most valuable fertilizing con- 

 stituents of the excreta. In the investigations of the Penn- 

 sylvania Experiment Station, to which reference has been 

 made, it was found that more than one half of the manurial 

 value of the food and a total of 63 per cent of the manurial 

 value of the excreta was in the urine. If it is allowed to 

 run to waste, as is often done, the larger proportion of this 

 plant food is lost. Practical means of handling and pre- 

 serving the urine is one of the difficult problems connected 

 with the management of a dairy barn. Another point that 

 comes into any general consideration of the subject is the 

 proper management of the manure and the losses that occur 

 from leaching and fermentation. The New Jersey Experi- 

 ment Station found that when solid cow manure was exposed 

 to ordinary leaching for 109 days, it lost 37.6 per cent of its 

 nitrogen, 51.9 per cent of its phosphoric acid, and 47.1 per 

 cent of its potash. Mixed dung and urine lost in the same 

 time 51 per cent of its nitrogen, 51.1 per cent of its phosphoric 

 acid, and 61 per cent of its potash. Over one half of the 

 total value was lost in less than four months' exposure to 

 ordinary weather. The loss in fertility from one cow by 

 the leaching of the manure would amount to $ 12.50 per year. 

 It would add 25 cents per 100 pounds to the cost of milk 

 from cows producing 5000 pounds per year. These losses, 

 especially of nitrogen, are partly accounted for by fermenta- 

 tions which set the ammonia free and make the other con- 

 stituents more soluble. 



