100 GENETICS [Bot. Absts., Vol. VI, 



of butter-fat below what the dams of these daughters produced. Spermfield Owl only raised 

 his daughters on the average 0.027 per cent of butter fat over what the dams of these daughters 

 produced. — (4) There are 224 sires of known transmitting ability for net butter fat. Of this 

 number only 99 sires raise the butter-fat production of their daughters over that of their 

 dams. The sires which raised the production of their daughters' butter fat most were Sans 

 Aloi 81012, Signal's Successor 72758, and Golden Glow's Chief 61460. The sires which made 

 the deepest impress on the breed by raising the butter fat of the largest number of daughters 

 over that of their dams was Hood Farm Torono with 34 pairs and an average increase for each 

 daughter of 121.51 pounds of butter fat. The next bull, Spermfield Owl, with 26 pairs raised 

 the butter-fat production 97.71 pounds on the average for each of his daughters. Some of 

 the bulls lowering the production of their daughters markedly were Gertie's Son of Washing- 

 ton 83799, Hood Farm S. Tormentor 96311, and Oxford Lad's Owl 75599.— (5) The informa- 

 tion summarized above was arranged to reveal the transmitting qualities for milk production, 

 butter-fat percentage and butter fat of Jersey sires to their sons. There were 159 sires which 

 had sons whose progeny performance was known. Of this number 69 or significantly less than 

 half had sons who raised the butter-fat production of their daughters over that of their dams. 

 — (6) The sires of superior merit are defined as those which raise the milk production and 

 butter-fat percentage of their daughters as compared with that of their dams. The inferior 

 sires are defined as those sires who lower the milk production and butter-fat percentage of 

 their daughters as compared with the same variables in their dams. The superior sires so 

 defined were arranged by the amount of butter fat that they increase the production of their 

 daughters over that of their dams. The inferior sires were classified according to the amount 

 of butter fat that they decrease the production of their daughters in comparison with that 

 of their dams. These two groups of sires are subjected to four generations of pedigree analy- 

 sis to determine their inbreeding and relationship, the amount of Island and American 

 stock, "males and females" and "on the sire's side of the pedigree and on the dam's side of 

 the pedigree," and the individual animals most frequently repeated into two groups of pedi- 

 grees. — (7) There are 28 sires in the group of sires superior in their transmitting qualities 

 for milk production and butter-fat percentage. In the group of sires inferior in their trans- 

 mitting ability for these two characters there are 47 sires, a ratio of 1 to 1.7 Such a difference 

 speaks for itself. It emphasizes with startling clearness the need of exact knowledge of the 

 transmitting qualities of bulls to be bred as sires and of the necessity for exact knowledge of 

 the inheritance of milk production and butter-fat percentage. — (8) The inbreeding coefficients 

 show that the sires of superior merit have 7.08 per cent of the greatest possible inbreeding up 

 to the fifth generation. The inferior sires are inbred 9.65 per cent of the greatest possible 

 amount (continued brother and sister mating). The group of sires poorer in their transmit- 

 ting qualities are consequently more inbred than the group of sires with superior transmitting 

 qualities. — (9) The analysis of the pedigrees for the amount of relationship that may exist 

 between the sire and dam of the individual bulls in the superior group and in the inferior group 

 shows that there is little or no difference in the amount of this relationship within the two 

 groups. — (10) The resolution of the four generation pedigrees into the Island-bred Jerseys 

 and by difference into the American-bred Jerseys showed the mean number of Island males 

 in the pedigrees of the superior sires' group to be 8.07 and the mean number of females 7.79. 

 The mean number of Island-bred males in the inferior sires' group were shown to be 6.94. 

 and the mean number of females 6.55. The group of sires which increased the production of 

 their daughters over that of their dams had, consequently, more Island-bred stock in their 

 pedigrees. The females in each group of the pedigrees had a smaller proportion of Island- 

 bred individuals than the males had in each of the groups. — (11) Study of the pedigrees of 

 these two groups of sires discloses the fact that all the animals which appeared in the pedi- 

 grees of the superior sire on the male side of the pedigrees more than four times or on the 

 female side of the pedigree more than three times also had appearances in the pedigrees of 

 the sires inferior in their transmitting qualities. This fact alone makes it clear that the 

 appearance of certain famous animals in the pedigree of a given bull is no guarantee of that 

 particular bull's worth. — John W. Gowen. 



