222 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 



tion. The shorter the time unit the more nearly possible will 

 it be to realize these conditions over the period of the test. It 

 is, in this regard, exactly with the hen as with the cow, where 

 the recent researches of Gavin* as well as those of Wilson,' 

 have demonstrated most clearly that the most adequate time 

 unit for the measurement of a cow's innate milk producing 

 ability taking all things into account is not the year test, nor 

 the 30 days test, nor even the 7-day test, but the one day test 

 when production reaches its maximum. This (revised as sug- 

 gested by Gavin) gives us the measure of what each cow is 

 hereditarily and physiologically capable of doing if the attend- 

 ants, the weather and every other external relation, will do 

 their parts. 



We have then to choose a particular short period for getting 

 our reliable measure of a hen's fecundity. Why take winter 

 production? Because, in a word, it is in this period that the 

 differences in innate reproductive capacity between different 

 individuals are most strongly marked.^ It is probable that a 

 shorter and earlier period would furnish a still better measure 

 of innate fecundity than the winter period, particularly as the 

 environmental conditions in mid-winter are not the best. For 

 practical purposes, the poultryman who operates his trap-nests 

 after the fall and early winter months, is paying a high price 

 for knowledge which is of very little use to him from the 



^Gavin, W. The Interpretation of Milk Records. Jour. Roy. Agr. 

 Soc, Vol. 72,, 1913. 



Studies in Milk Records : The Influence of Foetal Growth on Yield. 

 Jour. Agr. Sci., Vol. V, 1913, pp. 309-319. 



Studies in Milk Records : On the Accuracy of Estimating a Cow's 

 Milking Capability by Her First Lactation Yield. Ibid, Vol. V, pp. Z77- 

 390, 1913. 



^Wilson, J. The Inheritance of Milk Yield in Cattle. Proc. Roy. 

 Dublin Soc, Vol. XIII, pp. 89-113, 1911. 



The Elimination of the Unprofitable Cow. Jour. Dept. Agr.. Ireland, 

 Vol. XIII, No. 4, 1913. 



"It may be noted here that the writer's conclusions on the above point 

 have been independently confirmed by Professor James Wilson and Miss 

 Murphy, working upon Irish laying records (cf. Jour. Dept. Agr. Ireland. 

 Vol. XIV, No. 2). The results of the English Utility Poultry Club's 12- 

 month laying competition at Harper-Adams College also show clearly 

 the importance of the early fall and winter laying as a measure of innate 

 fecundity. 



