Having the right management program helps producers effectively increase output of gilts.
Gilts have a major impact on the cost and productivity of a breeding herd. Their replacement rate (culls, mortality) has a profound impact on herd profitability.
On the productivity side, gilts usually have lower farrowing rates and fewer born alive, compared to sows in their middle parities.
More importantly, however, data indicates that gilts that produce large litters at first parity will continue to produce large litters over their lifetime. The cost side of the equation is related to cost of gilts and replacement rate (culling plus mortality).
Historical Focus Historically, commercial producers have concentrated gilt development activities on health control, isolation and acclimation, not on selection, growth, conditioning and nutrition. Factors such as minimal weight at service (260 lb.), age at first service (210 days) and mating on second or third estrus have been emphasized.
However, the real focus should be on gilt development to maximize lifetime production. Increased square footage, small group size, diet programs to control growth while meeting targeted backfat, genetic selection and facility improvements have considerably modified gilts that are destined for reproduction.
Gilts reach 200 lb. at an earlier age and are very lean (less than 0.72 in. backfat). So, they may have lower body reserves for lifetime production.
One benefit of herds converting from farrow-to-finish to farrow-to-wean is that producers usually have excess space for gilt development and at a lower cost. This has allowed maturing gilts to grow rapidly with improved health and develop into maternal-looking females.
A second benefit is time for proper development because producers frequently bring in gilts as weaners or feeders for disease management strategies. Producers who gain in productivity also bear the costs.
Recommendations Gilts should be allowed 10 sq. ft./head from 100-150 days of age, 12 sq. ft./head from 150 days of age, and 15 sq. ft./head from 200 days of age. Pen flooring should be smooth and nonabrasive.
Gilt developer barns should use self-feeders similar to a typical finishing barn. If gilts reach 180 lb. in less than 140 days of age, implement a restricted diet followed by a flushing program to improve longevity.
Records Evaluation Accounting and sow recordkeeping systems have done a poor job of identifying the outcome of employing such strategies as increasing square footage for gilt growth.
By applying the National Pork Producers Council's (NPPC) chart of accounts and using existing sow record systems, these interventions can be evaluated properly.
The Carthage Veterinary Clinic uses PigCHAMP to track all reasons for gilt removal. This is most easily done if you label a herd as a gilt herd. Include all animals in the gilt herd during the development phase as a separate herd. By doing this, all history of that individual gilt or group is transferred to the permanent record. At the same time, by cost accounting developing gilts separately, various financial programs will track the net expense.
Figure 1 illustrates the replacement gilt price on the cost/weaned pig. If you increase the space/gilt in the staged program as outlined, the cost/developing gilt increases by $7.75/head ($36/7.6 sq. ft. standard contract). With a weaned pig price of $30/head, a herd needs to increase lifetime production by only 0.26 pigs to pay the gilt development facility cost.
Table 1 illustrates the effect of replacement rate on cost/weaned pig.
Data is accumulating, evaluating the results of improved gilt development. Table 2 summarizes the gilt productivity changes in a designed program.