4 MASS. EXPERIMENT STATION BULLETIN 438 



When this weekly record was supplemented by daily trapnesting in September, 

 there was no significant increase in the accuracy of the records. Olsen calculated 

 the regression line for one-day-a-week records and estimated the production of 

 100 Leghorns. He found that 44 percent of the calculated records were within 

 10 eggs; 58 percent, within 15 eggs; 73 percent, within 20 eggs; 85 percent, within 

 25 eggs; and 89 percent, within 30 eggs of the actual production. His second 

 measure was no more accurate than the first. 



Lerner and Taylor (1940), from a stud}' of 714 Leghorn pullets, conclude that, 

 where the number oi eggs laid is the only measure of breeding value used, trap- 

 nesting for the winter months is as efficient a guide to family selection as is trap- 

 nesting for the year. Neither system is accurate if the records of the dams alone 

 are used. These workers point out that the components of the annual record 

 need to be considered in an efficient breeding program. 



PORTIONS OF COMPLETE RECORDS MAY BE OF VALUE 



For accurately determining the value of limited trapnesting, the method should 

 be applied to a flock over a period of 3'ears as the only guide in selective breeding. 

 Under such conditions data would be obtained on the effectiveness of the method. 

 It would be desirable also to study the effectiveness of limited trapnesting sup- 

 plemented by complete trapnesting and also to make use of complete trapnesting 

 on a control flock. 



So far as we are aware, the ^•alue of limited trapnesting has been deduced from 

 the records of birds constantly under complete trapnesting. The data lo be pre- 

 sented fronj the Massachusetts Station have been taken trom pedigreed Rhode 

 Island Reds that had complete trapnest records and on which progeny testing 

 was used to a considerable extent. It cannot be said, therefore, that the data 

 suffice to answer the question as to what might happen when limited trapnesting 

 alone was applied. In other words, the question arises as to whether or not in- 

 herited teciindity characters could be combined in the same way through limited 

 trapnesting as has been done through complete trapnesting. 



Data to be presented cover a seven-year period from 1936 to 1942 inclusive. 

 The records made by 1684 Rhode Island Red females during their first laying 

 year are considered. These birds were all bred for characters associated with 

 high fecundity. The stock was hatched in March and April, and complete daily 

 trapnest records were secured for the first laying year. Annual records as used 

 in this study include a 365-day period beginning with the first egg, differing from 

 contest records which usually begin October 1 and terminate September 22. 



Kinds of Limited Trapnesting Used 



A. First two days of each month beginning October 1 and ending September 2. 



B. First week of each month beginning October 1 and ending September 7. 



C. Daily during October. 



D. Daily during August at the end of the year. 



E. Daily to January 1. 



Information Desired Through Limited Trapnestinr 



1. Probable annual egg record. 



2. Probable egg weight to January 1. 



3. Probable hatching season egg weight. 



4. Probable annual egg weight. 



5. Probable age at first egg. 



