Lactation Studies. X. Total Daily Production as Affected by Number of Times Milked, Number of Times Stimulated, and Method of Stimulation

An experiment was conducted to measm'e the milk production response to increased frequency of milking and to mammary gland stimulation per se. A total of 25 cows was employed in two trials. The treatments compared were twice-daily milking (2 ), four-times-daily milking (4 ) and either two-times-daily milking plus hand stimulation without milking (2 H) or two-times-daily milking plus oxytocin injection (2 I) midway between each milking interval. Treatments 2 X H and 2 I compared to treatment 2 X resulted in a 1.0 to 1.5% nonsignificant increase in production. Treatment 4 resulted in a milk production increase of 7.9% over treatment 2 . Further, this increase was attained by the second day on the increased milking frequency. The rapidity of the production response, plus the lack of response to additional stimulations per se, suggests that stimulation > oxytocin ) prolactin ) increased milk synthesis is not the explanation. Rather, that frequent milking )reduced intramammary pressure ) increased secretion is probably the explanation.