56 Oattle Problems. 



strain, which draws on its root-ends ; whether this, liereto- 

 fore mysterious emblem of )ield, be regular or irregular, 

 or /iJ/'-s/i/i'i/, angular, or ■winding in its various outline 

 forms; tlic form, of course, varjing with different forms 

 in the hrecch-growth of cows ; or with the form of the 

 mould, or muscles, underneath. Having used the term 

 "lop-sided," it may here be explained by calling atten- 

 tion to the most evident and familiar of all the influences 

 that affect the form of the Yield Mark hy frequent strain; 

 the effect of which is shown conspicuously in the unequal- 

 sided Yield Mark in many large-uddered cows. 



Viewed from a position behind the cow, the left side of 

 the bag, — as seen most clearly in the left hind quarter — 

 in many cows — sec I'igs. lo, 12, Plate IV. — hangs lower 

 down than the opposite side. The Yield Mark also, in 

 such cases, usually extends higher uj), reaching in some 

 cases, higher than the vulva. — See Figs. 4, 10, 11, and 12, 

 Plate IV. — while the border shadings where the strain di- 

 minishes — extend both wider and lT,igher on the left, or 

 chiefly on the left side of the udder and Yield Mark. 



As the increase in the depth of the udder is due to in- 

 crease of gravitation ; and this force is naturally the same 

 on eit/ier side, we cannot ascribe increased depth in the 

 left side, or left hind quarter, to increase of yield weight, 

 primarily, on that side. Nor is it necessary that we should, 

 for there is much 7nore strain on the farther or left side of 

 the udder during the process of milking, than on the right or 

 nigh side ; and the deepening of the left side — most con- 

 spicuous in the deeper hind quarter — is the effect of this 

 supplementary pulling or handling-strain on the left, more 

 than on the right side of the bag. 



Furthermore, the increase in hight and width of the 

 Yield Mark, on the same left side is also the result of in- 

 creased strain from hand-milking, and the forcible drawing 

 over and stretching down of that side of the udder which 



