Lactation Studies. I. Effect of Gestation

摘要: Summary A total of 82 production records (Holstein, Guernsey and Jersey breeds) were utilized to study the effect gestation on yield. The cows fed managed for near-maximum yield did not have access pasture during period studied. Daily milk weights butterfat tests available 19 Holstein cows, eight which carried calves a minimum 223 days. In latter group, five milked three times daily twice daily. There was no difference in rate decline lactation between two groups (milk, F.C.M. butterfat) with advancing pregnancy. four faster from 181−223 days pregnancy as compared 101−180 Butterfat test more variable preconception periods progressively less length increased. Milk 53 carrying calf 210 revealed that inhibition started at approximately same time regardless number daily, age cow, breed, month conception, level cow or calving interval up 18 mo. curve 10 pregnant first 365 tendency slow after 330 This is contrast an accelerating than 180 Lactation appears follow cyclic pattern following conception unlike observed estrual cycles.