Summary and Conclusions 



The relative nutritive value of redtop hay, grown under a 100 lb. of 

 nitrogen fertilization per acre over a two-year period and harvested at 

 two different stages of maturity and also as aftermath was estimated by 

 means of twenty-six protein and energy digestion and utilization balance 

 experiments. The animals used were two Guernsey steers, two Jersey 

 steers, two Holstein steers, and three adult wethers. The maximum ac- 

 ceptability of the hays was determined by the same three adult wethers 

 used in the digestion balance experiments. 



Chemical composition of the hays was affected by delay in the date 

 of first cutting. Fiber content increased and protein content decreased 

 with delayed harvesting. There were slight compositional differences in 

 the hays cut on corresponding dates between years, but these could be 

 attributed to differences in rainfall during the two growing seasons. 



Digestibility of nutrients, especially protein, fiber and energy, was 

 adversely affected by delayed date of cutting. The percentage decrease in 

 digestibility per day delay in harvesting the forage ranged from 0.35 to 

 0.50%. Nutritive value and digestibility changes followed a similar pat- 

 tern. Delay in harvesting the forage decreased the nutritive value, par- 

 ticularly digestible protein and net energy content. Net energy was more 

 sensitive than TDN as a method of comparing nutritive value. This was 

 indicated by the higher percentage difference between values on the two 

 first cutting dates. 



There was very close agreement between the nutritive value of the 

 same hays fed to cattle and sheep. This confirms previous results of coop- 

 erative work between this station and the Pennsylvania station (13). 



The acceptability of the hays by adult wethers followed the diges- 

 tibility in that the more digestible hays were more acceptable to the 

 animals. 



Redtop is a forage species that can be grown successfully in the 

 Northeast. When grown with a fertilization of 100 lb. of nitrogen per 

 acre, harvested about the middle of June in northern New England and 

 properly cured, a hay is obtained which is palatable and has a nutritive 

 value comparable to that of timothy hay. 



