Determination of Optimum Drying Off Time for Dairy Cows Using Decision Analysis and Computer Simulation

• Published in: Journal of dairy science 1988-11, Vol.71 (11), p.3080-3091
• Main Authors: O’Connor, J.J., Oltenacu, P.A.
• Format: Article
• Language: English
• Subjects: BOVIN LAITIER; COMPUTADOR; COMPUTERS; COWS; DAIRY CATTLE; DATE; DECISION MAKING; DRY PERIOD; EPOCA; GANADO DE LECHE; MODELE; MODELOS; ORDINATEUR; PERIODE DE TARISSEMENT; PERIODO DE SECADO; PRISE DE DECISION; SEASONAL VARIATION; TIMING; TOMA DE DECISIONES; VACA; VACHE; VARIACION ESTACIONAL; VARIATION SAISONNIERE
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(88)79908-7

A model of the drying off decision problem was constructed in which the effect of parity, month of freshening, length of dry period prior to lactation, and the length of open period during the current lactation on milk production were considered. The seasonal variations in the price of milk and feed costs were also considered. The net return per year was used to compare the effect of different times of drying off. Optimum length of dry period for first lactation cows freshening in summer to fall was 47 to 49 d if open between 40 and 160 d and 50 to 53 d if open more than 160 d. For cows freshened during winter to spring, the optimum dry period was 50 to 53 d if open between 40 and 130 d and 53 to 63 d if open more than 130 d. For mature cows freshening during summer to fall, the optimum dry period was 48 to 56 d if open between 40 and 130 d and 56 to 84 d if open more than 130 d. If cows freshened during winter to spring, the optimum length of dry period was 51 to 54 d, 54 to 85 d, and 80 to 112 d for cows open 40 to 70 d, 70 to 130 d, and more than 130 d, respectively.