Crops 



(See Agronomy) 



Dairy Husbandry 



Vitamin D Content of Forage Varies Greatly 



A study was started four years ago to determine if milking dairy 

 cows maintained under New Hampshire farm conditions needed supple- 

 mental vitamin D. It was soon found that the first problem was to learn 

 more about the vitamin D content of the common forages which the cows 

 ate and the factors affecting it- 



The results of the study show that the vitamin D content' of forage 

 varies widely and depends on a number of factors. The vitamin D content 

 of first-cutting forage harvested at the generally recommended stage of 

 maturity was usually low when mowed and it could not be increased 

 greatly by ultraviolet irradiation. Second-cutting forage was often higher 

 in vitamin D when mowed and it contained appreciable amounts of vitamin 

 D after irradiation. Relatively high levels of vitamin D were found in for- 

 ages cut at a mature state and these values were increased markedly after 

 irradiation. 



The results of this study indicate that first-cutting forage harvested 

 at the generally recommended stage of maturity cannot be considered as 

 a good source of vitamin D even if it is field cured. Because second-cutting 

 hay generally contains considerable vitamin D after field curing, the prac- 

 tice of ensiling first-cutting forage and making the second cutting into hay 

 appears to be a desirable one. This is true not only from the standpoint 

 of the vitamin D intake of the cow, l)ut also in conserving other nutrients. 



H. A. Keener 



Effect of Texture on the Digestibility and 

 Utilization of Concentrates by Dairy Cows 



Because of the questions raised by a preliminary report of the work 

 on the nutritive value of the so-called "fine" and "coarse" textured feeds, 

 it was deemed advisable to repeat the work on an expanded basis. This 

 vear the comparison included a very coarse texture and pellets in addi- 

 tion to the coarse and the fine textures studied in 1951. These four con- 

 centrate mixtures represent the principal types found in dairy feeds sold 

 in the Xew England area. All four mixtures were made from the same 

 original lots of ingredients and consequently were of practically the same 

 chemical composition. Enough of the concentrates were mixed at one time 

 to carry through the whole experiment. 



In 16 complete digestion and utilization experiments with 4 mature 

 cows, the fine mixture excelled the coarse, very coarse, and the pellets 

 significantly in digestible protein and in total digestible nutrients. The 

 coarse, the very coarse, and the pelleted feeds were essentially equal in 

 nutritive value. 



The results of this experiment substantiate those reported in Bulletin 

 394 (1952) of the New Hampshire Station. They also support the ob- 



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