The Effect of Rate of Nitrogen Fertilization, 

 Geographic Location, and Date of Harvest 

 on Yield, Acceptability, and Nutritive 

 Value of Timothy Hay 



Summary 



The effects of 50, 100 and 150 lb. nitrogen fertilization per acre and 

 different dates of harvest on the yield, chemical composition, and nutri- 

 tive value of the first cutting of two varieties of timothy. Commercial 

 and Essex, grown at two different locations were studied for three con- 

 secutive years with ten animals. 



Acceptability of some of the hays was determined using three Shrop- 

 shire wethers. Complete energy balances of all the hays with all animals 

 were determined by the use of two open-circuit indirect calorimeters. 

 The nutritive evaluation of all the hays was done on the basis of total 

 digestible nutrients, digestible energy, metabolizable energy, and net 

 energy, all directly determined. 



Delay of harvest affected the composition and nutritive value signi- 

 ficantly. The crude protein decreased about 40-50 per cent and the crude 

 fiber increased 20-25 per cent as the harvest was delayed from June 1 to 

 June 30. The rate of decrease in total digestible nutrients, digestible pro- 

 tein and energy, metabolizable energy, and net energy was from 0.35 to 

 0.50 percentage units per day as the harvest was delayed after June 1. 

 The order of voluntary intake of some of the hays fed to adult wethers 

 followed that of the digestible and net energy. 



The yield in the highest rate of nitrogen fertilization (150 lb. per 

 acre) decreased considerably due to lodging. Also below-average tem- 

 peratures decreased the yields of the forages in the June 1 and 14 har- 

 vests at both locations. 



Personnel at the New Hampshire Agricultural Experiment Station 

 conducted research on the nutritive value of timothy hay for a three- 

 year period. The project was a cooperative effort of the members of the 

 Departments of Animal Sciences, Agronomy and Biochemistry. The 

 studies were related to the location, varieties, persistency, nitrogen fer- 

 tilization, cutting dates and their effect on the nutritive value of timothy 

 hay. 



Research at many stations has clearly indicated that nitrogen fer- 

 tilization increases the yield of feed per acre (3, 10, 13, 17) . Date of 

 cutting, or stage of growth when the forage is harvested, greatly influ- 

 ences its nutritive value and acceptability by the animals (6, 11, 12, 13, 

 14, 16) . Recently it was reported that the aftermath of a forage is greatly 



This study was conducted as part of the contributing project of the New Hamp- 

 shire Agricultural Experiment Station to the Northeast Regional Forage Evaluation 

 Project (NE-24). 1500/4/65. 



