Reproductive Management of Dairy Cows with Particular Reference to Organic Systems Holstein-Fresian cattle Grolier Electronic Publishing, Inc. Biological Efficiency Reproduction Production Efficiency Profitability Overall Requirements for Organic Milk Production Systems • Compact seasonal calving patterns, • Maximal production from grazed grass, • Low involuntary culling rates • Continuous genetic improvement of the herd Reproductive Targets Compact Calving: 90% calved in < 80 days Low Culling Rate for infertility: < 5%. Calving Interval: 365 day calving-to-calving Shortening Postpartum interval Improving Reproductive efficiency Submission Rates Conception Rates Post-Partum Interval Dairy Cows Mean=26 days (15-50 Days) Beef Cows Mean=55 days (25-180 Day) Postpartum reproduction - cattle Aim to have a calf per cow per year with peak lactation to correspond with peak grass growth To Ensure Rapid Onset of Oestrous Cycles Post Calving • Cows calve in a moderate BCS • Ensure high DM intakes post calving & minimise BCS loss – Minimise Negative Energy Balance (NEB) • Calve heifers early • Consistently use Sire with strongly positive sub indices for Fertility Main Factors Affecting Pregnancy Rate Conception Rate Pregnancy Rate Heat Detection Rate The Effect of Different Heat Detection and Conception Rate on % of Herd Pregnant at 90 Days After Onset of Breeding Season Conception rate 90 Heat 70 Detection Rate % 50 40 60 50 40 30 96 91 83 71 91 82 73 61 76 68 59 48 67 59 50 40 59