The Dairy Cow — Scientific Findings. 



407 



We learn that from her first calf up to and including the 

 seventh year, the cow gives gradually increasing returns for a 

 given quantity of feed; after the seventh year they gradually 

 diminish until the eleventh to the thirteenth year, when the 

 returns from feed are less than with the heifer. There is an in- 

 crease in weight during the first years, followed in later years 

 by some loss in weight. This table is in harmony with the ex- 

 perience of dairymen as to the most profitable years in the life 

 of the cow. 



621. Advance in lactation and productivity of feed. — Thorne^ 

 also studied the feed consumption and fat returns of thirty-one 

 cows used in tests at the Ohio and Wisconsin Stations, and deduced 

 the table given below for the purpose of showing the returns from 

 the cow as the lactation period advances: 



Returns for feed consumed as time since calving increases — Ohio 

 and Wisconsin Stations. 



We learn that shortly after calving the cow is at her best in 

 the fat she returns for feed consumed, and that during this period 

 there is usually a loss in body weight. As time since calving 

 increases the return of fat for feed consumed is reduced, the 

 cow, when well nurtured, increasing somewhat in weight. Dur- 

 ing the last stages of lactation the cow returns only about three- 

 fourths as much fat for feed consumed as shortly after calving. 



622. Influence of time from calving on milk flow. — Sturtevant, ' 

 studying the diminution in milk flow of cows from month to 

 month after calving, reached the conclusion that this decrease 



1 Loc. cit. 



» Rept. New York (Geneva) Sta., 188d. 



