18 CIRCULAR 905, U. S. DEPARTMENT OF AGRICULTURE 
Of the pigs in this experiment, those in the first lot received no pasture, 
those in the second lot received grain equal to 3 percent of their body 
weight while on pasture, and those in the third lot were given grain 
equal to only 1 percent of their body weight while on pasture. 
LaABorR REQUIREMENTS 
In analyzing the feeding systems and crop rotations that maximize 
returns, emphasis was placed on the greatest output of lvestock 
product from a given acreage, or the production of a given quantity 
of livestock product with the least possible cost for feed. This pro- 
cedure is justifiable in the sense that costs of feed make up the greater 
part of total costs in livestock production. Other production factors 
are also important, however.. Next to feed, labor makes up perhaps 
the largest single item of cost for all livestock, and in the case of dairy 
cows it constitutes an important portion of total costs. As costs of 
labor for any one type of livestock vary, depending on the system 
of feed utilization, consideration of the labor factor is important. 
Accordingly, this section relates labor requirements to different 
livestock rations. 
If the feeds fed are grown on the farm, the forage-grain utilization 
system selected may affect labor requirements in both crop and live- 
stock production. “The effect of the utilization system on crop labor 
depends mainly on the way in which the forage is harvested (whether 
pastured or made into hay).’ Increasing the proportion of forage 
in the ration fed a particular kind of livestock may aftect labor re- 
quirements for livestock in three ways: (1) It may reduce the daily 
rate of production and thereby prolong the time an animal must 
be kept in order to produce a given output; (2) it may affect the daily 
labor requirements for feeding and caring for an animal; and (3) it 
may affect the distribution of the work load thr oughout the year. 
LABOR REQUIREMENTS IN RELATION TO FEEDING SYSTEM 
When labor is available, or can be hired, the objective is often one 
of minimizing the combined labor and feed cost of producing a par- 
ticular output of livestock product. If labor requirements in pro- 
ducing 100 pounds of pork, for example, do not differ under different 
rations, the feed combination with the lowest feed cost will be the one 
that minimizes the cost of both feed and labor. I¥ labor requirements 
change proportionately with changes in the proportion of forage in 
the ration, the analysis is still not difficult; the cost of forage can 
then be adjusted to include the additional labor costs associated with it. 
The optimum ration will be the one that minimizes the adjusted feed 
costs for a given output. Analysis is made more complex, however, 
when labor requirements do not vary proportionately with changes 
in the ratio of forage to grain in the ration. As shown in table 8, 
labor requirements do not generally vary in direct proportion with 
the amount of forage in the ration. Yearling steers fed a moderate 
® However, on the basis of other studies in this connection it is assumed that 
the effect of changes in the rotation on labor requirements in crop production is 
unimportant. Here only the effects on labor needed for producing livestock 
with alternative rations are considered. 
