CAN WE IMPROVE REPRODUCTIVE PERFORMANCE IN DAIRY CATTLE?
The successful genetic selection for higher milk production in Holstein cows has nearly doubled the average milk production in the United States since 1960, to over 11,000 kg/year. Over the same time period, there has been a dramatic decline in the reproductive performance of dairy cows. The average number of days open [interval from calving to conception] and the number of services per conception have increased substantially. In order to decrease the longer lactations and the number of cows culled for reproductive reasons it is very important to improve our reproductive management practices. Achievement of optimum herd reproductive performance [calving interval of 12 or 13 months with the first calf born at 24 months of age] requires concentrated management activities especially during the first 100 days following calving.
The following management activities are needed to pursue during the early postpartum period to reach or approach the optimal calving interval: careful surveillance and assistance at calving, prevention of post parturient diseases, early diagnosis and treatment of postpartum uterine abnormalities, accurate detection of oestrus, correct timing of insemination, reducing the effect of heat stress and early pregnancy diagnosis.
Key words: dairy cow, dystocia, metabolic disorders, post partum uterine abnormalities, detection of oestrus, timing of insemination, summer heat stress, pregnancy diagnosis