VITAMIN A FOR DAIRY CATTLE 7 



sequently are not represented in the records for Table 2. Here the evidence 

 seems about evenly divided. The cows receiving vitamin A supplement averaged 

 a shorter interval between heats, a shorter time from calving to first heat, a slightly 

 smaller number of services and half as many calves born dead. On the other 

 hand, they had a somewhat higher incidence of retained placenta, more abor- 

 tions, and all the cases of calves which died a while after birth. 



The heifers (see Table 4) which received extra vitamin A did not gain quite as 

 much as those not receiving it; regularity of heat was about the same; and number 

 of days between heats and number of services required were not greatly different, 

 although favoring slightly the group which received supplemental vitamin A. 



The record of the calves in Table 5 is consistently slightly in favor of the group 

 whose dams received the vitamin supplement. They averaged slightly heavier 

 at birth and were in slightly better condition. Those saved for the herd showed 

 a slightly greater average gain in weight at the end of a month. Also there were 

 less than half as many calves born dead; and, since there were nearly twice as 

 many calves from this group as from the group not receiving the vitamin A 

 supplement, the difference is somewhat greater on a percentage basis (2.8 percent 

 born dead as contrasted with 14.0 percent). 



Table 5. — Record of Calves Dropped during the Experiment. 



Dams Receiving 



Vitamin A 



Supplement 



Dams not Receiving 

 Vitamin A 

 Supplement 



Records Number Records 



during of during 



Experiment Records Experiment 



Number of individuals. 

 Average condition of 



calves at birth Good 



Average birth weight of 



all living calves Pounds 75 . 3 



Average birth weight of 



calves saved Pounds 76.3 



Average weight at 1 



month of calves saved Pounds 105.3 

 Average gain in a month Pounds 29.0 



Calves born dead Number 3 



Sex of calves: 



Male Number 53 



Female Number 55 



108 57 



108 Fairly good 57 



104* 73.4 49 



64 76.3 31 



105.0 

 28.7 



*There were 105 living calves. Through an oversight, one was not weighed. • 



The weights given have been corrected for breed differences in the make-up of the groups. 

 Differences due to varying sex ratio were also checked, but were not sufficient to be of any signi- 

 ficance. 



