Herd Reproductive Programs
Dairy Pipeline: November 1995
Ray L. Nebel
Extension Dairy Scientist, Reproduction
Dairy herd reproductive programs have historically been structured to monitor uterine involution of the postpartum cow and implement treatment if needed. The traditional repro program included exams to determine pregnant cows and problem cows. Problem cows are those not seen in heat past the voluntary waiting period (traditionally 60 days), those requiring 3 or more services and cows with a previous problem on examination, such as cystic ovarian disease or metritis. Frequency of herd visit was based on herd size. Small herds (less than 100 cows) were examined once a month and larger herds weekly or usually biweekly due to the number of cows to examine. The benefits of a herd reproductive program can only be measured against economic returns based on herd performance. Returns for reproductive programs are associated with reduced days open, forced replacement (culling) associated with reproductive failure, losses due to abortion and calf mortality. Direct cost of a reproductive program are associated with call fees, rectal examinations, drugs and treatments. Indirect cost to the farm include labor and time organizing cows for the herd visit. The primary returns to the farm depend on the value of forced replacement and days open. Additional losses are associated with differences in milk yield between cows which leave the herd for reproductive failure versus replacement heifers. Cull reproductive cows on average yield 3,000 lbs more milk than a replacement heifer. Herd reproductive programs should be designed to control the factors most highly correlated with reproductive performance. Research has shown that heat detection, especially prior to first insemination, and conception rate are the most important factors influencing reproductive performance. In general, as the heat detection rate decreases, palpations per cow increase in herds and reproductive programs become more costly. More cows are examined for missed heats and presented open at pregnancy examinations. Increased incidence of metritis and other reproductive disorders increase palpation numbers but to lesser extent than heat detection. Prebreeding heat detection rate can be improved by synchronizing cows with prostaglandin. Prostaglandin can induce estrus in cows 7 to 16 days after heat. A majority of cows will be in heat in less than 7 days from the administration of prostaglandin. Cows not observed in heat can be injected 14 days later and re-synchronized. This increases potential heats during a period when observations can be maximized. Days to first insemination must be controlled to achieve optimal calving interval. Prostaglandin synchronization every 14 days allows observations to be grouped and can decrease days to first insemination.