632 



RATE OF GROWTH OF DAIRY COW 



would seem reasonable from inspection of Fig. 2 to assume the value 

 of h, the maximum, as 20.5 months of age when the animal weighs 

 635 pounds — the average weight of the Jersey cow at maturity having 

 been found by Eckles^ to be 902 pounds. A is therefore 2 X 267 

 = 534 pounds, and w = 902 — 534 = 368 pounds. Equation (3) 

 after evaluation of K h becomes 



log 



xi - 368 



534 - {xi - 368) 



Calculating x as before, we get Table IV 



= 0.0765 - 20.5) 



TABLE IV. 



If all the assumptions are correct, and if pregnancy under the 

 conditions at which the animals were kept did not interfere with 

 their growth, then the observed weights before calving, at 29 months 

 of age, should be greater by at least 55 pounds, the weight of the calf 

 at birth, than the calculated weights. The effect of pregnancy on 

 growth, however, is not well known, the evidence being somewhat 

 contradictory,^ and no conclusions can therefore be drawn from this 

 rather too close agreement. 



^ Cf. Marshall, F. H. A., The physiology of reproduction, London, 1910. 

 Minot, C. S., /. Physiol, 1891, xii, 97. Watson, J. B., /. Comp. Neurol, and 



