Green pasture feed

The principal factor that influences the a-tocopherol content of milk is the feed of the cow, as influenced by the season of the year. Kanno et al. (1968) reported that summer milk produced on green pasture feed averaged 33.8 pg a-tocopherol/g fat, while winter milk produced on dry-lot feeding averaged 21.6 pg a-tocopherol/g fat. Similar findings have been reported by King et al. (1967) and Seerless and Armstrong (1970). 

In milk approximately 90% of the yellow color is because of the presence of -carotene, a fat-soluble carotenoid extracted from feed by cows. Summer milk is more yellow than winter milk because cows grazing on lush green pastures in the spring and summer months consume much higher levels of carotenoids than do cows ham-fed on hay and grain in the fall and winter. Various breeds of cows and even individual animals differ in the efficiency with which they extract -carotene from feed and in the degree to which they convert it into colorless vitamin A. The differences in the color of milk are more obvious in products made from milk fat, since here the yellow color is concentrated. Thus, unless standardized through the addition of colorant, products like butter and cheese show a wide variation in shade and in many cases appear unsatisfactory to the consumer. 

Vitamin A has essential roles in vision, bone and muscle growth, reproduction and maintenance of healthy epithelial tissue. Naturally occurring precursors of vitamin A are found in some seeds, leafy green vegetables and forages such as lucerne. The common form of the precursor is p-carotene, which can be converted into vitamin A in the intestinal wall. Carotene is present in considerable quantities in pasture, lucerne hay or meal, and yellow maize. Carotene and vitamin A are rapidly destroyed by exposure to air, light and rancidity, especially at high temperature. Since it is difficult to assess the amount of vitamin A present in the feed, diets should be supplemented with this vitamin. 

From the standpoint of nutritional value, the Vitamin A content of butter is important. As the source of Vitamin A in butter is p-carotene or other carotenoid pigments in the feed of the cows, the content of this vitamin varies considerably, being highest in the summer when the dairy herds are in pasture and lowest in winter when there are no green feedstuffs in their rations. A portion of the carotene... 

Earlier varieties of triticaie did not offer much promise for milling and baking they resembled their rye parent more than their wheat parent. However, bread of good quality has been made from more recent triticaie selections. So far, the main use for triticaie has been as a feed grain, pasture, green chop, and silage crop for animals. 

---