Influence of the Wean-to-first-service Interval on the Subsequent Farrowing Rate and Litter Size of Sows in Thailand

Abstract

Data from 6,871 parity records, collecting from 8 commercial swine breeding herds which have been under the health and management services of the Faculty of Veterinary Medicine, Kasetsart University for 2 years, were used to determine the relationships between the wean-to-first-service interval (WFS) and the subsequent farrowing rate and litter size. The regression procedures both logistic and polynomial were utilized to find the models best explaining the variability of the data.Sows were most fertile when the WFS was between 3-5 days and 20-25 days. The farrowing rate for this group of sows was likely to be above 85 percent. On the other hand, the farrowing rate for sows having WFS between 0-1 day and 10-17 days could be expected to be lower than 80%. The strong association between WFS and farrowing rates suggested that a strategy to maximize sow lactation intake was likely to result in improved herd farrowing rate but may not result in improved herd litter size since WFS indicated only a small fraction of litter size variability (R² = 0.089).