MILK PRODUCTION 



487 



The foregoing results show no perceptible effects from the tem- 

 perature fluctuations within the range of these experiments either on 

 the lots kept in the cooler stables from the start nor on those in 

 warmer quarters when the temperature of the latter fell. 



Davis l reports experiments at the Pennsylvania Station, covering 

 three seasons, in which comparable lots of cows were kept in an open 

 shed and in an ordinary "bank" barn. It was found that the milk 

 yield of both was similarly affected by sudden drops of temperature 

 but that the milk yield of the exposed group decreased more rapidly 

 during the winter than did that of the sheltered group, the difference 

 in the average daily yield for the entire season varying from practi- 

 cally nothing in 1911-1912 to about three pounds in 1913-1914. It was 

 observed that the exposed cows had the keener appetites and con- 

 sumed more roughage than did the sheltered animals. Both groups 

 maintained good health. The amounts of milk produced per Therm 

 of estimated net energy contained in the feed and also per Therm of 

 net energy in excess of the estimated maintenance requirement were 

 as shown in the following table from which it appears that the pro- 

 duction by the sheltered lot was slightly the more economical. 



TABLE 129. MILK YIELDS OF SHELTERED AND EXPOSED Cows 



A number of instances have also been reported in which the sub- 

 stitution of a single thickness of muslin in cow stables in place of 

 glass windows has proved satisfactory. 



1 Penna. Expt. Sta., Rpt. 1913-1914, pp. 183-226. 



