474 EXPERIMENT STATION RECORD. [Vol.37 



averages of from 64.8 per cent in the junior three-year-old group to 48.3 per 

 cent in the aged cow group. Revi.sed Advanced Registrj- requirements are 

 calculated from the actual average fat production of cows in the different age 

 groups based on 12 lbs. for an aged cow — the present aged requirement. 

 Except for the aged cows, the revised standard is higher for all age groups 

 than tlie present standard. 



The A. R. O. fat production record of every daughter of each sire is reduced 

 to a percentage of the association requirements, and the averages of these per- 

 centages for the daughters of each bull are considered the comparative values 

 of the bulls as revealed by tlie performance of their A. R. O. daughters. Of the 

 32 bulls compared on this basis King of the Pontiacs heads the list, having 

 149 A. R. O. daughters, with ,an average percentage value of 186.4 ; King Segis 

 stands second, with a value of 181.2 per cent; and Lord Netherland De Kol 

 stands lowest among the 32, with an average value of 133.9 per cent. When 

 compared on the basis of the number of A. R. O. daughters Lord Netherland 

 De Kol, who has 122 such daughters, is exceeded only by King of the Pontiacs. 

 The 32 sires are also compared on the basis of percentage performance of their 

 A. R. O. daughters based on the revised age requirements above mentioned. No 

 very great differences occur in the relative standing of the sires when compared 

 on the two bases. 



An attempt was also made to obtain a measure of the performance of a bull 

 by the performance of his sons. To this end the records of the 7,632 daughters 

 of the sons of the bulls in que.stion were calculated to a percentage basis, as 

 outlined above, these records being taken as a measure of the son's performance. 

 The correlation coe0icient between the average value of bulls and the average 

 value of sons of tlie.se .'jame bulls as shown by the average percentage values of 

 their daughters is 0.6326±0.071.5. This high coirolatlon is not considered 

 evidence that fat production is transmitted throntrh the male line. 



The method suggested by the author of testing out a new sire is to " breed him 

 only to a few older cows of known breeding capacity, then hold him in reserve, 

 using him only when absolutely necessary, till the results of this first trial are 

 completed. If the majority of these first heifers prove to be .satisfactory pro- 

 ducers, the bull could then .safely be used generally in the herd ; if not. he 

 should be discarded." 



Cow-testing associations, E. M. Clabk (Illinois St a. Circ. 196 {1917), pp. 

 10, figs. 2). — Brief information is given on the advantages of cooperative cow- 

 testing associations, including hints on their formation and operation. 



Feeding dairy cattle, A. C. McCandlish (/oiro Sta. Circ. 34 (1917), pp. 3S).— 

 This popular treatise deals with the subject under the headings of constituents 

 of feeds, functions of nutrient.s. definitions and characteristics of feeds, re- 

 quirements of a ration, and the feeding of dairy animals. 



Studies in the cost of market milk production, A. C. Anderson and F. T. 

 RiDDELL (Michigan Sta. Bui. 277 (1916), pp. 58, figs. 9). — Data are presented 

 on the cost of producing milk for the city market on 20 farms in the territory 

 of the Grand Rapids Milk Producers" Association. These data cover the years 

 1914 and 1915, 25 farms being .studied each year, and one of the authors spend- 

 ing his entire time on the farms. 



On all of the farms where the investigations were carried on the production 

 of milk was only one of the enterprises of the farm. On a few of them it was 

 practically the sole enterprise, and crops were grown simply to feed the herd. 

 On other farms milk production was coupled with grain, vegetables, live stock, 

 or fruit production for the market. None of these other enterprises were con- 

 sidered in any manner. 



