272 EXPERIMENT STATION EECOED. 



vancing age has upon the yield and quality of the milk. The principal conclu- 

 sions reached are summarized as follows : 



''Milk flow. — At the outset and until the average cow was 7 years old the gen- 

 eral tendency was for the flow to increase in volume. That of her eighth year 

 tended to be lower than that of the seventh, much lower than that of the ninth, 

 and to resemble that of the tenth year. No cause was found nor .is stress laid 

 upon the sag. From the ninth year the trend was downwards. 



" Total solids. — In 3 cases in 4G the trend from the first figure to those fol- 

 lowing is upwards ; in 10 cases the change is nil ; in 32 cases the trend is down- 

 wards. 



" Fat. — In 3 cases in 46 the trend from the first figure to those following is 

 upwards ; in 14 cases the change is nil ; in 29 cases the trend is downwards. 



"Solids-not-fat. — In 9 cases in 46 the trend from the first figure to those follow- 

 ing is upwards ; in 14 cases the change is nil ; in 23 cases the trend is down- 

 w\ards." 



Similar studies made elsewhere are summarized. The diiferences from one 

 year to another were not striking. The author does not believe that the effect of 

 advancing years upon milk quality is profound enough to be of importance until 

 old age becomes imminent. 



Home-groAvn protein v. purchased protein; distillers' grains v. gluten 

 feed; summer silage v. soiling, G. A. Billings (New Jcrscij Stus. Bid. 20.'f, 

 j)p. 2S). — Three feeding experiments are reported. 



In the first experiment alfalfa hay was compared with purchased feeds as a 

 source of protein. Two lots of 4 cows each were fed for 2 periods of 60 days 

 each. When alfalfa hay was the sole source of protein the average daily yield 

 of milk per cow was 20.41 lbs. and the yield of fat 0.876 lb. The cost to pro- 

 duce 100 lbs. of milk Avas 94.36 cts. and the cost of 1 lb. of butter 18.82 cts. 

 When protein was supplied by distillers' grains, wheat bran, and cotton-seed 

 meal the average daily yiel^ was 24.63 lbs. of milk and 1.068 lbs. of fat. The 

 cost to produce 100 lbs. of milk and 1 lb. of butter was respectively 83.72 and 

 16.55 cts. The conclusion is drawn from the results of this experiment that 

 alfalfa and other home-grown pi'otein feeds may well furnish a large part but 

 not the whole of the protein required to balance rations in which silage or other 

 roughage of like character is used. 



In the second experiment including 4 cows and lasting 60 days, dried dis- 

 tillers' grains were compared with gluten feed in quantities making the nutri- 

 tive ratios practically the same. Of the gluten feed ration the average daily 

 yield per cow was 23.31 lbs. of milk and 0.994 lb. of fat. The cost of production 

 per 100 lbs. of milk was 86.40 cts. and of 1 lb. of butter 17.36 cts. When dis- 

 tillers' grains were fed the average daily yield was 23.85 lbs. of milk and 1.026 

 lbs. of fat. The cost of producing 100 lbs. of milk was 80.50 cts. and of 1 lb. of 

 butter 16.04 cts. 



Summer silage was compared with soiling, the experiment including the herd 

 of 25 cows aud the feeding periods being 3 weeks for each ration. The average 

 daily yields of milk per cow on wheat forage and corn silage were, respectively, 

 22.35 and 21.71 lbs., the average yields of fat 0.953 and 0.929 lb., the cost of pro- 

 ducing 100 lbs. of milk 74.72 and 74.80 cts., and the cost of producing 1 lb. of 

 butter 15.01 and 14.99 cts. The shrinkage on the silage following the forage 

 was, therefore, about 3 per cent, which was less than the average shrinkage for 

 the herd at the same season in previous years. The silage ration, therefore, 

 more than maintained the yield of milk obtained with the forage crop ration. 



