Swine Gestation Calculator

A swine gestation calculator estimates when a pregnant sow or gilt may farrow by adding the typical pregnancy length to the breeding or insemination date. The familiar livestock rule is three months, three weeks, and three days, which corresponds to approximately 114 days. This tool uses exactly 114 elapsed days for the central estimate and also shows a practical window from day 111 through day 117. That range reflects normal biological variation and helps managers prepare without treating a single calendar date as a guarantee. Accurate breeding records are essential. When a sow is served more than once during estrus, record each service and ask the herd veterinarian which date should guide management. Conception may not occur at the first observed mating, and an uncertain input naturally produces an uncertain due date. Breed differences are generally less important than individual history, litter size, parity, health, nutrition, environment, and the accuracy of the breeding record. Yorkshire, Landrace, Duroc, Hampshire, Berkshire, Pietrain, and crossbred animals are commonly planned around the same 114-day baseline. The estimate is most useful for scheduling routine pregnancy checks, moving the sow to clean farrowing accommodation, organizing staff coverage, and checking that necessary supplies are ready. Follow the farm's veterinary program for vaccination, parasite control, nutrition, body-condition monitoring, and movement. Avoid sudden feed or housing changes near term. Prepare a dry, disinfected farrowing area with appropriate temperature zones, water access, bedding or flooring, and safe space for piglets. Observe the sow more frequently as the calculated window approaches. Signs such as udder development, milk letdown, vulval swelling, restlessness, and nest-building can indicate that farrowing is near, but signs and timing vary. A calculator cannot confirm pregnancy or detect complications. Contact a veterinarian when the sow appears distressed, labor does not progress, abnormal discharge is present, the pregnancy runs beyond the expected window, or any herd-specific protocol calls for assistance. Combining the calendar estimate with direct observation, reliable records, and professional veterinary guidance supports better preparation and safer outcomes for both sow and piglets.