Robert W. Blake

Assessing the comparative economics of a biotechnology: Artificial insemination dairy sires

Much opportunity exists to increase economic returns from the artificial insemination, dairy sire selection decision. This article measures potential returns to producers with alternative objective functions, management and financial characteristics. The costs of wrong decisions from incorrect information are measured by differences between alternative sets of top-20 Holstein sires selected from more than 400 available. Correct specification of the objective function is most important. Determination of planning horizon and conception rate also merits allocation of some scarce management resources. Correct information about length of calving interval, female mortality rate, and opportunity cost of capital, however, is economically inconsequential.

Profitability And Risks In Dairy Feeding Programs: A Multiperiod Optimization

INTRODUCTION scheduling compensating tissue depletion and repletion; and (4) compare the risks associated Considerable research has been conducted with alternative milk yields, calving seasons, and over the years to determine optimal rations for feeding systems. dairy cattle. Dean et al. extended earlier work through a comprehensive examination of milk production functions, isoquant shapes, and feed METHOD OF ANALYSIS systems to maximize income over feed cost (IOFC) for a given point in time. Computerized Under the assumption that maximum IOFC is formulations of dairy feeding rations are now the dairymans goal, a multiperiod linear procommonplace and either minimize feed costs or gramming (LP) model is constructed. Its objecmaximize IOFC to meet nutrient requirements tive is to determine the level of expected IOFC, under assumed static conditions. weight loss-weight gain strategy (schedule), and Computer models to formulate rations have ration composition for Holstein cows with two not directly considered the role of body tissue alternative calving intervals (13 and 15 months) catabolism (depletion to provide energy during and four yields of 3.5 percent milkfat milk periods of peak nutrient requirements) and (13,000, 15,000, 17,000, and 19,000 pounds in 300 anabolism (storage of energy when requirements days). Multiperiod quadratic programming (QP) are exceeded by appetite). Talpaz et al.s optimal is used to determine the trade-off between profit control model of the lactation curve appears to and risk for cows with a 13-month calving interbe the lone exception, but empirical solutions of val. Profit is maximized, or risk minimized, over real problems are complex and none have been the entire lactation rather than for a single point reported. Further, the effect on expected costs or (day) in the lactation. Thus, unlike conventional profits of alternative management and feeding feed ration formulations, the optimization is repractices has been considered without regard to cursively dynamic. the risk incurred by the producer. The models are constructed with six or seven Both of these neglected issues are addressed in two-month periods, except for the fifth period, the current study. We build upon the Dean et al. which is of three months duration. Cows are in and Talpaz et al. studies by empirically examinlactation in all but the last 60-day period. Thereing interrelationships between milk yield, energy fore, actual lactations are 330 days (13-month concentration of the ration, and storage and decalving interval) or 390 days (15-month) long. Inpletion of body tissue on the profitability and terdependence among the stages occurs because risks of managing the calving interval (producof the cows ability to mobilize body tissue in tion cycle). Expected IOFC and risks are meaearly lactation to help meet energy and protein sured for optimal feeding plans during the calving requirements and to replete the tissue reserve in interval for mature Holstein cows in northeast late lactation and the dry period. Texas, the major dairy center of the state. Most herds in the area range from 60 to 120 cows, rely on Coastal bermudagrass for pasture, and buy all DATA grain, by-products, and hay. Alternative milk yields, calving seasons, and calving intervals are Milk Production examined. Specific objectives are to: (1) examine the efEstimated daily milk yields across a 300-day fects of milk yield on IOFC; (2) determine the lactation for mature cows follow McCraw and cost of extending the calving interval; (3) deterButcher and depend on calving season. Averages mine optimal changes during the calving interval by period are the means of predicted milk yields in the energy composition of total rations by for days 1, 15, and 30 of each month in the