12 



BULLETIN 1024, U. S. DEPARTMENT OF AGRICULTURE. 



make them more readily comparable. The time of beginning the 

 winter period and the length of it are also averaged, to have the 

 graphs on a uniform basis. The winter period in 1915-16 began 

 December 22 and lasted 122 days, while the winter period in 1917-18 

 began December 7 and lasted 134 days. This makes the average 

 time of beginning the winter period December 14, and the average 

 length of the last section of the winter period 16 days. 



In studying the variations in the weights of the cows from month 

 to month, it should be kept in mind that the average time of calving 

 for the 2 years represented in figure 7 was practically the same as 

 the time when cows were turned on to pasture. 



The average birth date of the 19 calves of lot 1 during 1915-16 

 and 1917-18 was 2 days after the cows were turned on pasture; for 



Average length of feeding period. 

 Winter period 128 days. Summer period 196 days. 



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Fig. 7. — Gains and losses in weight of cows. 



the 10 calves of lot 2 in 1917-18, 7 days before; for the 16 calves of 

 lot 3 in 1915-16 and 1917-18, 6 days after ; and for the 10 calves of 

 lot 4 in 1915-16, 1.5 days after. 



Figure 8 shows how the calves gained in weight during 1915-16. 

 The average weight of the calves for each weight day, designated by 

 the vertical lines, was obtained by dividing the total weight of the 

 calves in each lot by the number of cows in each lot. It should be 

 kept in mind here that most of the calves were dropped in April and 

 in May and that about one-half were dropped before and the other 

 half after the cows were turned on pasture. 



Figure 7 shows that the cows gained in weight during the winter 

 period until they began to drop calves. This is generally expected 

 in wintering beef cows. The cows lost in weight during the rest of 

 the winter and continued to lose weight during the first 28 days 



