32 BULLETIN 873, U. S. DEPARTMENT OF AGRICULTURE. 



If the hay is to bo baled in the field, from the windrow or cock, it 

 must be cured out more than when it is to be put into the barn or 

 stack. The curing should be carried as far as possible without making 

 the hay so brittle that it will break or shatter easily when being 

 baled. The loss of water by shrinkage will be considerably less in 

 hay properly field-cured for baling than in hay properly field-cured 

 to be put in barn or stack. 



First-cutting hay, etc. — The terms ''first-cutting hay," "second- 

 cutting hay," etc., are used to distinguish different crops of hay, such 

 as alfalfa and clover that are cut more than once a year. It has 

 become necessary to use these terms in the market, especially for 

 alfalfa, because a consumer may, for various reasons which are not 

 always very clear or well-based, prefer a certain cutting for feeding a 

 certain class of stock. 



SUMMARY. 



(1) The question of shrinkage is one that has always been of inter- 

 est to those engaged in the production and utilization of hay. The 

 producer wants to know how much hay shrinks because be believes 

 that it results in a direct money loss when he grows hay for the market. 

 The shipper and dealer want to know how much hay shrinks, so that 

 they can make allowance for this factor and thereby avoid disputes 

 and losses. 



(2) The percentage of shrinkage in hay is influenced by the follow- 

 ing factors: (1) water content when cut, (2) maximum water content 

 when stored, (3) normal water content when cured, (4) minimum 

 water content, (5) atmospheric humidity, and (6) effect of time. 



(3). Many experiments have been conducted, during the last 30 

 years, to determine the rate of shrinkage in hay in the barn and 

 stack. The loss in weight was found to range from 0.29 per cent to 

 42.2 per cent and the gain in weight ranged from 0.4 per cent to 

 10.7 per cent, making a total variation of about 53 per cent. 



(4) All efforts by investigators to determine the average rate of 

 shrinkage, in order to formulate a definite rule to be used at harvest 

 time to calculate the percentage of "dry" or marketable hay, have 

 failed. The reason an unvarying shrinkage rule can never be used 

 for a large producing territory is because of the effect of such factors 

 as variation in the time of cutting, methods of curing, and the weather, 

 which will always cause a wide difference in the percentage of shrink- 

 age in hay on individual farms within a given territory. 



(5) The experiments show that there is no correlation between the 

 lapse of time and the percentage of loss by shrinkage. In other 

 words, the amount of loss that may occur during 3 months has no 

 mathematical relation to the amount occuring during 6 months, 9 

 months, or other period. 



(6) The widespread publication of experimental data showing 

 comparatively large losses by shrinkage, during several months, has 

 been misleading, especially to producers, because the investigators 

 failed to point out that the greater part of the loss occurs before the 

 hay is in proper condition to be baled or marketed and that the loss, 

 which is practically of water only, is simply a part of the natural 

 curing process, and, therefore, should have no commercial value. 



