236 AGRICULTURE OF MAINE. 



These tables present a number of points of interest to the 

 breeder of cattle. We note : 



I. The average age of the herd bulls used to sire the 967 

 calves included in the statistics was just under three years. The 

 median age of these herd bulls was approximately two and a 

 half years. This means that one-half of the calves were sired 

 by bulls under two and a half years old at time of service 

 Seventy-five per cent of all the calves (as shown by the third 

 quartile age) were sired by herd bulls less than about three 

 years and nine months old at time of service. Less than 15 per 

 cent of the calves were sired by bulls five or more years old. 

 Let us consider for a moment what these facts mean. A bull 

 must be at least three years old before the breeder can possibly 

 have had any opportunity to test the milk producing capacity of 

 his daughters. But ^8.p per cent of all the calves covered m 

 these statistics zvere sired by bulls under three years of age. 

 In other words, in the breeding operations of a large number 

 of Maine's most progressive and wide-awake breeders (for such 

 the cooperators in this record scheme are) more than half of 

 the calves produced in a given interval of time are sired by 

 bulls about whose ability to transmit milking qualities absolutely 

 nothing definite can by any possibility be known. It is doubt- 

 less entirely fair to assume that essentially the same conditions 

 regarding cattle breeding methods obtain in other places gener- 

 ally. Is it remarkable tlmt progress is so slow? 



2. In the female half of the herd the conditions are better. 

 We see that if we exclude heifers bred for their first calves, 

 the average age of the breeding cows is approximately five and 

 a half years. This is an age when, on the average, cows are 

 nearly if not quite at their best as regards milk production. 



3. Out of 878 calves, 166, or 18.9 per cent, were the first 

 calves of heifers. The average age of these heifers when suc- 

 cessfully served for these first calves was approximately one 

 year and seven months. Three-quarters of the heifers were 

 successfully served for their first calves before they were 2.1 

 years old. 



