MINERAL NUTRITION 157 



in any given year, this is a matter which is difficult to regulate in practice. That 

 the endeavor in this particular instance was not successful is evidenced by the 

 figures. 



The conclusions that seem justified are two: 



(I.) That the low ash ration apparently had no immediate adverse effect on 



jiroduction. 

 (2.) That the mineral supplement apparently had no immediate favorable 



effect. 



Composition of the milk 



The milk from each cow in the herd was sampled for five consecutive days each 

 full month that she was in milk. Total solids and fat have been determined each 

 month during the course of the experiment. Total ash, calcium and phosphorus 

 have been determined every three months. 



Table 6. — Composition of the Milk 



Whole Herd Mineral group Non-mineral group 



Total solids 12. .53 12.58 12.53 



Fat 3.99 3.96 4.03 



Total ash 0.711 0.712 0.710 



Ash as per cent of total solids 5.67 5.66 5.66 



Calcium 0.121 0.123 0.120 



Phosphorus 0.099 0.102 0.097 



Expressed as percentar e of the liquid milk. 



These figures have been corrected for differences in the breed make-up of the groups. Cor- 

 rections for stage of lactation have not been necessary, as the average stage of lactation at the 

 time the samples were taken was the same in both groups. 



The differences between the groups in this respect are seen to be very slight, and 

 while they favor the "mineral" group (except in the fat content) they are not of 

 sufficient magnitude to be of any significance. 



Reproduction 



Reproductive troubles have not been serious in either group. The average 

 length of time after calving before reappearance of oestrum has been: 



Mineral group 38 days 



Non-mineral group 45 days 



Regarding regularity in recurrence of oestrum the records show the following: 



Good Fair 



Mineral group 11 1 



Non-mineral group 9 3 



The average number of services required to breed has been: 



Mineral group 1.13 times 



Non-mineral group 1.30 times 



Seventy-one per cent of the breedings have been from one service, only one 

 cow in each group giving serious trouble in this respect. 

 Other irregularities have been: 



One premature birth (8 months) in the "mineral" group. 

 One case of nymphomania (chronic buller) in the "mineral" group. 

 One case of cervicitis (inflammation of the neck of the uterus) in each group. 

 Three cases of retained afterbirth (two of them in the same cow in successive 

 years) in the "non-mineral" group. 



