Alfalfa-Oat-Clover Pasture for Dairy Cattle


cal for the irrigated pastures. At these nutrient levels, a 1,000-
pound cow obtaining total digestible nutrients from pasture
needed to support body maintenance and 12 pounds of her daily
production of 4 percent milk would require 0.60 acre of unirri-
gated or 0.55 acre of irrigated pasture. To supply nutrients
required to support maintenance and to make normal growth,
a 700-pound heifer would require 0.49 acre of unirrigated or
0.45 acre of irrigated pasture.
 Employing a total digestible nutrient level of 275 pounds
per acre biweekly (shown by base line in Figure 1) as the amount
needed for grazing purpose from unirrigated pasture, an annual
average of 3,378 pounds would have been utilized for grazing.
An average of 1,207 pounds of total digestible nutrients annually
in excess of grazing needs would have been available for preser-
vation and storage.
 Using 300 pounds of total digestible nutrients biweekly as
the level needed for grazing from irrigated pasture, an annual
average of 3,623 pounds would have been grazed, and 985 pounds
would have been available for harvest. Comparable average
annual values calculated using a 275-pound biweekly level for
unirrigated pastures would have been 2,571 and 435 pounds,
respectively, for the same two years.
 Body Weight Gains.-Annual body weight gains of heifers
on unirrigated pastures averaged 637 pounds per acre of pasture
grazed and ranged from 233 to 917 pounds for the different pas-
ture seasons. Daily gains averaged 1.2 pounds, which was 128
percent of the Missouri Standard (11). During the first three
years when alfalfa was grazed in the prebud stage, daily gains
averaged about 1.3 pounds; this growth rate was about 143
percent of the Missouri Standard. In 1960, alfalfa frequently
was in the bud stage and occasionally in early bloom when
grazed. Utilization at a later stage of growth was accom-
panied by a slower animal growth rate (1.0 pound daily) and
a higher yield of total digestible nutrients per acre.
 Pasture irrigation increased yield of total digestible nutri-
ents, and this was accompanied by corresponding increases in
average weight gain per acre. Animals on irrigated pasture
gained an average of 159 pounds more per acre in 1955-56 and
368 pounds more per acre in 1956-57 than those on unirrigated
pasture. Growth rate, when expressed as percentage of the
Missouri Standard, was lower for animals grazing irrigated
pastures than for those on unirrigated during comparable years.
Higher average initial weight of animals on unirrigated pasture