AGRICULTURAL RESEARCH IX NEW HAMPSHIRE 17 



Further time trials are to be run and will include the use of an all- 



wood rake built during the winter of 1943-1944. 



'fc) 



E. W. Foss 



DAIRYING 



Analysis of D. H. I. A. Records 



A total of 4030 lactation records of cows in New Hampshire Dairy 

 Herd Improvement Associations was used as a basis for the analyses. In 

 many of the comparisons the data were analyzed separately for each breed 

 to determine breed differences. Some of the more noteworthy results fol- 

 low : 



I. Month of freshening: (1) Summer months are more associated 

 with lower lactation yield than are fall and winter months. Jerseys showed 

 no significant relation. (2) Month of freshening had no significant effect 

 on length of lactation. (3) Cows freshening in mid summer and late svmi- 

 mer return less milk per unit of grain fed during lactation than at other 

 times of year. 



II. Age: (1) Maximum production was obtained from cows at five 

 to six years of age in most instances. (2) Lactations made prior to three 

 years of age were definitely longer than those made after that age. (3) 

 W^ithout exception, each breed showed a wider milk-grain ratio when three- 

 to four-year-old group was compared with two- to three-year-olds. There 

 were no consistent changes between remaining age groups. 



III. Dry period: (1) Subsequent lactation yields were highest for 

 a dry period approximately 65 days, with A-ery little variation between 45 

 and 85 days. There was an abrupt increase in yield as the dry period in- 

 creased up to 40 days. (2) There was no consistent practice regarding 

 amount of grain fed during dry period. Jerseys were fed much less grain 

 than other breeds. 



IV. Length of lactation: (1) Lactations of approximately 12 months 

 appear most desirable to secure maximum 305-day milk production. 



V. Milk yield and grain feeding : ( 1 ) The data indicate the principle 

 of diminishing returns in that for all breeds additional increases in grain 

 feeding created progressively smaller responses in milk yields. (2) The 

 correlation between increased milk yield and milk-grain ratio was positive. 



This study indicates the influence of certain herd management prac- 

 tices on milk production. Attention on the part of dairymen to the appli- 

 cation of these relationships would directly affect the amount of milk pro- 

 duced on New Hampshire farms. 



K. S. TvIoRROw, H. A. Keener 



Management Practices in University Herd 



This project, designed to supplement the findings of the previous 

 project, involves detailed analyses of certain management practices cover- 

 ing the past 25 years in the dairy herd at the L'niversity of New Hamp- 

 shire. 



Work on the project to date has consisted entirely of preparing pro- 

 duction data for tabulation. All records of milk and butterfat are being 



