178 EXPERIMENT STATION RECORD. [Vol.40 



ment Farm at Beltsvllle, Md., is described. The milk and butter-fat records, 

 the quantities of digestible nutrients in the feed consumed, and the feed cost 

 of milk and butter fat are given in tables, and the labor requirements, the 

 health and comfort of the cows, and the preservation and handling of the ma- 

 nure under the two systems are compared in the discussion of the results. 



The open shed used the first year, providing approximately 75 sq 4 ft. of floor 

 space per cow, had the north end and the east and west sides closed up to 

 within 18 in. of the plate, while the south end had only a fence to keep the 

 cows inside. The last two years a new shed was used, of which the south side 

 was entirely open, and the north side and both ends had large doors swung from 

 the top which were raised in summer and lowered in winter. The closed baru 

 was a modern, well-ventilated structure. 



A herd of 1 pure-bred Guernsey, 2 pure-bred Holsteins, 10 grade Jerseys, and 

 8 cows of miscellaneous breeding was divided into two groups, of which one 

 during the first year was kept in the open shed and the other in the closed barn. 

 The second year the groups were reversed, and the third year they were again 

 reversed. Only the records for the five months, November to March, were 

 studied, and owing to the Irregularity In calving these records did not in any 

 case cover the entire period Of five months, thougb all records fell within that 

 period, and all the cows did not have three years' records that were compar- 

 able. In order that there should be no difference in the records of individual 

 cows due to time of freshening, production records covering the same lengtb 

 of time in the two barns and taken the same time after calving were compared. 



It was found that the cows consumed somewhat more feed and produced 

 slightly more milk in the open shed than when kept in the closed barn, but the 

 increase in production did not quite offset the extra feed cost. In the open 

 shed some of the more aggressive cows deprived weaker and more timid ones 

 of their share of the feed and of the normal advantages of the shed, which re- 

 sulted in lower milk yields from the cows thus mistreated. 



Excluding milking and feeding. Blightly more labor was required to care for 

 the cows in the open shed. The manure under the open-shed system was ap- 

 parently well preserved until it was hauled, and was handled more economically 

 than in the closed barn. Cornstalks in the manure were Sufficiently decomposed 

 to be handled successfully with the manure spreader. As compared with the 

 closed barn, 08 per cent more bedding was required in the open shed, but the 

 cows were cleaner and more comfortable. There was little difference in the 

 time required to bed the cows under the two systems, and in the open shed it 

 was possible to use cornstalks or other coarse material for the purpose. There 

 was apparently little, if any, difference in the frequency of injuries to cows 

 under the two systems. 



The relation of milk yield to age at first calf. R. C. Towi.es {Maryland St a. 

 Hitl. ;_'/7 (litlS), pp. 827-240).— A study through the first four lactation periods 

 was made of 15 Ayrshire cows to determine the Influence of the age at which 

 the first calf was produced upon milk production. Data with reference to pro- 

 duction during the first four lactation periods of cows in milk two or more 

 years, showing the sires and dams, comparative production by lactations, and 

 comparative lengths of lactations, are presented in tables. A special effort 

 was made to have all other factors as nearly comparable as possible, with the 

 age of first calving as the only variant. 



The average production per lactation of t cows first calving under SO months 

 of age was 3,993 lbs. of milk, of 5 cows first calving between 80 and 36 months 

 5,353 lbs., and of ti cows first calving above .">»'> months of age 5,296 lbs. The 

 average fat production per lactation for the three groups was lo.~>, 199, and L96 



