326 Journal of Agriculture, Victoria. [10 June, 1919. 



pure-bred sires, and the milking records of tlie daughters and grand- 

 daughters of these scrub cows were compared with those of their dams. 



Seven scrub cows, four heifers, and two heifer calves were selected 

 as a foundation herd for this investigation, which was commenced in 

 1907. The animals were very inferior, being small, with limited 

 abdominal, i;dder, and vein capacity, and very unprepossessing as far 

 as quality and top lines were concerned. The illustrations are more 

 expressive than words in conveying a true impression of the type of 

 cattle used at the beginning of the experiment. 



Pure-bred Guernsey, Jersey, and Holstein sires Avere used on these 

 scrub cows, and all the heifer calves and the progeny of these heifer 

 calves were raised nnder similar conditions. 



The following table summarizes the results of two generations of 

 breeding with pure-bred bulls : — 



IOWA STATE COLLEGE DAIRY FARM. 



Increasing the Production of Scrub Herd. 



Table I. 



AVERAGE PRODUCTION OF SCRUBS AND FIRST AND SECOND 

 GENERATION CROSSES. 



Table II. 



PERCENTAGE INCREASE IN PRODUCTION OF CROSSES OVER SCRUBS. 



It will be seen that the first generation females proved to be very 

 much superior to their dams in production, and thus clearly demon- 

 strated tlie value of a pure-bred dniry sli-e as an investment for a common 

 or scrub herd, as well as for a high-grade or pure-bred herd. 



There was a great improvement in constitution, capacit.y, mammary 

 development, straightness of top line, quality, and type. This improve- 

 ment is still more marked in the second generation grades. 



