36 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



of fat instead of .36 making a ratio of structure to fuel of 1 to 18, but 

 only 18,545 heat units. Only 3-5 as much grass that we used for summer 

 fuel when we had heat and to spare. We all know that the cow loses 

 weight right along on 20 pounds of timothy hay per day. But we want to 

 learn why she gains on grass when giving milk. 



The composition and structural growth of plants helps us to under- 

 stand the reason. Most feeders say grass and silage are most valuable 

 because of their succulent or appetizing properties'. But we should say 

 more. That grass and' other plants grow by the circulation of water 

 carrying the mineral matter and nitrogen in compounds from the soil 

 through their roots up to the leaves, where carbon enters. Plant mater- 

 ial is thus formed in liquids and carried to all parts of the plant, as blood 

 is in the body, only plants have no pumping engine, and the circulating 

 tubes are divided into small cells that enlarge and fill up as! the process 

 of growth goes on. New cells are formed adjacent and the old ones fill- 

 ing up become inactive, dead, ready to be cured as hay. The fluid in the 

 undeveloped cells then evaporate and leave some of the minerals. But, 

 as the chart shows, they lose about 2-3 of their nitrogen compounds when 

 cured as hay. When cured as silage the most of this is retained, as in 

 grass shown on the chart. Grass and green cured feeds are worth more 

 because they retain more digestible nutriment. 



The long sunshiny hours of July evaporate more water from fresh 

 cut grass, than the shorter hours of June or October, therefore use plants 

 that are ready to be cured in these months for hay, and have a narrower 

 ration in the forage. 



According to Prof. Haecker's Bulletin No. 71 (which is simply more 

 deduction from the records of the herd of cows he has been working with 

 at the Minnesota Station for some years ,and has been telling us about at 

 our conventions) figures out the average protein, carbohydrates and fat 

 the cow used in these tests to make a pound of milk and a pound of butter 

 fat. 



Taking 3.85 per cent milk as a standard, he recommends .046 protein 



