114 



Produce of Calves- by a Herd of Coivs. 



2:oing six weeks. This I began doing in the commencement of 

 1838. I have now taken notes for this object with respect to 

 1000 cows bulled, and I here subjoin a Table taking the series 

 at 200 cows in each, which will show the results of my observa- 

 tions : — • 



Bulled. 



3 weeks. 



4 weeks. 



5 weeks. 



6 weeks. 



200 



158 



115 



107 



87 



200 



137 



92 



85 



71 



200 



142 



87 



80 



72 



200 



148 



94 



81 



78 



200 



139 



87 



74 



63 



1000 



724 



475 



427 



371 



The small variation between the different series in this Table is 

 very remarkable, I having expected that it would be much greater 

 than in the former one. 



By the means of these Tables I have now the opportunity of 

 calculating, first, the probable number of cows who have not gone 

 six weeks who will go that time, and of those who have gone six 

 weeks the probable number who will prove in calf. 



Although therefore, as I have said, I am not able to arrive 

 at anything like a certainty with respect to any individual cow 

 proving in calf, I have been able to calculate the number of calves 

 I shall have from all or any given number of the cows bulled 

 with much greater accuracy than I expected. In order, however, 

 to make this calculation, it is necessary to make an allowance for 

 the number of pregnant cows who may either slip their calves or 

 produce dead calves at their full time. Not having any data at the 

 time I began these observations on which to ground this allow- 

 ance, I took it at one in eight, which proves to be too great, for, 

 as it will have been seen from the first Table which I have in- 

 serted, I have had 181 live calves from 202 cows in calf, and 

 consequently I ought only to have deducted one in ten, instead 

 of one in eight ; and therefore the results of my calculations of 

 the probable number of calves I should have in any given period 

 have generally proved rather too low. In order to show that the 

 principles which I have adopted may be practically applied, I will 

 state several of the trials which I have made of my calculation. 



On the 22nd of October, 1838, I calculated that 1 should have 

 48 live calves previous to the 1st of August, 1839. I had 49. 



On the 24tli of January, 1839, I calculated that 1 should have 

 53 live calves previous to the 1st of November, 1839. I had 55. 



On the 18th of August, 1839, I calculated that I should have 

 37 live calves previous to the 25th of May, 1840. I had 41. 



