Variation in the Milk of Ayrshire Cows 



61 



if the conclusion just stated were true it would mean that if a 

 large number of cows were placed in environmental circum- 

 stances which were at once ideal and uniform we should ex- 

 pect the variation exhibited in milk production to be roughly 

 about one-half of that which we actually find when we meas- 

 ure this variation under ordinary circumstances. 



In the case of fat content of milk, individuality has clear- 

 ly much more to do with determining variation. Here the 

 effect of the environment is extremely small. 



TABLE 1. 

 Coefficients of Variation for Various Characters. 



Characters 



Number of children per family 



(New South Wales) 

 Area of comb (Domestic fowl) 

 Weight of spleen (English males) 

 Size of litter (Mouse) 

 Lambs per birth (Sheep) 

 Dermal sensitivity (English males) 

 Annual egg production (Domestic fowl) 

 Size of litter (Poland-China swine) 

 Size of litter (Duroc- Jersey swine) 

 Milk yield (Total lactation) 

 Milk yield (Daily average) 

 Fecundity* (Horse) 



Heart weight (English males) 

 Weight of kidneys (English males) 

 Weight of liver (English males) 

 Swiftness of flow (English males) 

 Body weight (English males) 

 Rev. maximum daily milk yield (For 



given agel 

 Weekly Milk Yield (Ayrshire cattle) 

 Breathing capacity (English males) 

 Strength of pull (English males) 

 Weight of shell of egg (Domestic fowl); 

 Body weight (Domestic fowl) 

 Weight of albumen of egg (Domestic 



fowl) 

 Length of red blood corpuscles. 



(Bufo tadpoles) 

 Weight of yolk of egg (Domestic fowl) 

 Amount of fat in mixed milk . 



(Daily fluctuations) 

 Tield of mixed milk (Daily fluctuations) 



Fat percentage of milk. (Ayrshire) 

 Weight of egg (Domestic fowl) 

 Brain weight (Bavarian males) 

 Length of forearm (English males) 

 Length of femur (French males) 

 Length of egg (Domestic fowl) 

 Stature (English males) 

 Horizontal circumference of skull 



(English males) 

 Specific gravity of egg (Domestic fowl) 



CoTfficient of 



Authority 



Variation 







4S.41 



Powys 





39.97 



Pear! and 



Pearl 



38.21 



Greenwood 





37.50 



Weldon 





3x78 



Pearl 





35.70 



Pearson 





34.21 



Pearl and 



Surface 



■ 27.41 



Surface 





26.00 



Surface 





25.78 



Gavin 





25.72 



Gavin 





24.77 



Calculated 

 Pearson 



from data of 



22.22 



Greenwood 



and Brown 



2L05 



Greenwood 



and Brown 



23.82 



Greenwood 



and Brown 



19.40 



Pearson 





18.91 



Greenwood 



and Brown 



17.998 



Gavin 





17.08 



This paper 





16.60 



Pearson 





15.00 



Pearson 





13.86 



Curtis 





12.66 



Curtis 





12.27 



Curtis 





•11.85 



Pearson 





11.31 



Curtis 





9.68 



Pearl 





9.05 



Unpublished 



data in this 





laboratory 



S.ST 



This paper 





8.36 



Pearl and 



Surface 



8.12 



Pearl 





5.24 



Pearson and Lee 



5.05 



Pearson 





4.24 



Pearl and 



Surface 



3.99 



Pearson and Lee 



2.87 



JIaedonell 





Pearl and Surface 



*Feeundity here means the fraction which the actual number of offspring aris- 

 ing from a given number of coverings is of the possible number of offspring under 

 the circumstances. 



