II. Effect of Different Levels of Nitrogen 

 Fertilization and Dates of Harvest on 

 Nutritive Value of Bromegrass Hay 



Introduction 



Economical milk production depends on maximum use of home-grown 

 feeds. The northeast is mainly a forage-growing section and in order for 

 dairying to remain profital)le in this area it is necessary to continue to 

 place more emphasis on maximum use of high quality forages grown in 

 this section. In the last ten years the northeastern agricultural experi- 

 ment stations have heen concerned with extensive studies related to the 

 hreeding, persistency and nutritive evaluation of various forage crops 

 adapted to this region. Because of the difficulty in holding stands of 

 legumes in this area, the New Hampshire Agricultural Experiment Sta- 

 tion has centered its attention on certain grasses which appear to have 

 possihilities of yielding large crops of high quality feed, if fertilized 

 sufficiently, managed properly and harvested at the right stage of ma- 

 turity. 



If a forage makes up a high percentage of the cow's ration, it must 

 he high in feeding value, acceptahle by the animal, and produce a high 

 yield per acre. 



Work done, at this station and elsewhere, clearly established that the 

 early cutting of certain species of forage improves their nutritive value. 

 The stage of growth in a forage greatly influences the acceptability of 

 the forage bv the animal. Early-cut forage is much more acceptable to 

 the animal than late-cut. Protein content is also higher per unit weight 

 when the forage is harvested early. Digestibilities of protein and energ\', 

 as determined by digestion experiments with dairy cattle, are signifi- 

 cantly higher in early-cut forages as compared to the same forage when 

 harvested at a later stage of maturity. 



Recent research has also indicated that liberal use of fertilizer in the 

 soil increases dry matter yield per acre. There is limited information 

 on the effects of such practices on the nutritive value, yield per acre, and 

 persistency of the species of forage. 



To obtain answers to some of these questions, a cooperative study be- 

 tween the Dairy Science, Agronomy, and Biochemistry departments was 

 undertaken. The over-all objectives of this cooperative effort were: 



1. To study the effect of different levels of nitrogen fertilization and 

 date of cutting on the nutritive value of forage. 



2. To study the effect of the above conditions on the yield of nutri- 

 ents per acre and also on the persistency of the species of the forage. 



3. To determine the nutritive value of the forage crops on the basis 

 of digestible dry matter, total digestible nutrients, digestible protein and 

 digestible energy. 



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