Apr. 24, 1916 Effect of Water in Ration on Milk 169 



this point distinct differences among different feeds, but that the effect 

 of any feed depends upon the composition of the other components of 

 the ration. He states that roots have a favorable effect upon milk 

 secretion, but tend slightly to lower the fat content. 



Koch (9) reports extensive feeding experiments at Rosenhof in which 

 cows were fed beet roots (Beta vulgaris), and gives the following conclu- 

 sions : 



An increase in fat units (total fat) with beet-root feed, an increase of the amount of 

 milk combined with a decrease in the fat content. However, the increase in quantity 

 exceeded the decrease in quality so much that the cows gave 6 per cent more total fat 

 on the beet-root ration.' 



PLAN OF INVESTIGATION 



The experimental work to determine the effect of water in the ration 

 upon the composition of milk was conducted at the Dairy Division farm, 

 Beltsville, Md., and included parts of three different lactation periods. 

 The four following methods for supplying rations of widely different 

 water content were tried: 



1. A full allowance of drinking water as compared with a limited 

 supply, the ration otherwise being alike in both cases. 



2. A heavy ration of turnips as compared with a dry-roughage one. 



3. Wet beet pulp as compared with dry beet pulp. 



4. Green crimson clover ^Trifolium iiricarnaium) as compared with the 

 cured hay. 



As the change in the fat content of the milk noted during the prickly- 

 pear experiments took place within a few days after the change in the 

 character of the ration and continued throughout the 80-day period, it 

 was decided that for this work two lo-day periods of feeding any one 

 ration, with a lo-day transition period intervening, and equal periods of 

 feeding the comparative ration, would give time enough for any change 

 in the composition of the milk to take place. In each series of experi- 

 ments the milk from each cow was weighed at each milking, and lo-day 

 composite samples were taken for analysis. The data obtained from 

 each series of experiments are given separately. 



FULL VERSUS LIMITED ALLOWANCE OF WATER 



In this series of experiments eight cows were used and all received the 

 same general treatment. For the first two lo-day periods the animals 

 were given water ad libitum twice daily. Then a definite quantity of 

 water, not more than 75 per cent of the full allowance, and in some cases 

 less than 65 per cent, was given for two lo-day periods following a lo-day 

 transition period. The quantity of water given in the limited water ration 

 was so reduced that, when watered once a day, all cows drank the quantity 

 allowed. After a second lo-day transition period, a full allowance of 

 water was again given for two lo-day periods. This completed the work 



1 Authors' translation. 



