Management of commercial swine breeding herds involves a thorough understanding of reproductive physiology, genetics, nutrition, immunology, disease control, environment, and other factors. (See also Abortion in Large Animals: Abortion in Pigs.) The closed-herd concept, which emphasizes preventive medicine strategies along with herd protection, minimizes the risk of disease loss when combined with sound nutrition and genetic selection. The breeding program should be evaluated at specified intervals to ensure that progress in efficiency is being made. Some efficiency parameters to review when analyzing herd reproductive performance are shown in Table 1: Management of Reproduction: Pigs: Reproductive Benchmarking Indices Used in Swine Herds. The postweaning performance of a herd can be measured by feed conversion, feed efficiency, total days to market, and postweaning death loss.

Problems on a swine farm can have a single cause or be caused by a combination of genetic, nutritional, environmental, health, and management factors. When investigating a swine herd problem, the practitioner should concentrate on the herd and not individual animals. Accurate, up-to-date records are essential when investigating a herd problem. When analyzing a herd and its records, a certain percentage of “abnormal” animals and/or reproductive problems are to be expected.

Table 1
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Reproductive Benchmarking Indices Used in Swine Herds Reproductive Index Target Interference Level Wean-to-estrus interval (95% in estrus by 10 days postweaning) <7 days >10 days Repeat services at 21 (+/– 2) days <10% >17% Abnormal returns to service (25–37 days) <3% >5% Multiple matings >90% <85% Abortions <2% >3% Not-in-pig 1% 2.5% Farrowing rate >85% <80% Total piglets born/litter >11.5 <10.5 Live piglets born/litter 11–12 <10 Stillbirths <1% >3% Mummies <0.5% >1% Litter scatter (≤7 pigs/litter) <12% >15% Weaned/litter >9.5 <9 Preweaning mortality <12% >16% Litters/mated female/year >2.4 <2.2 Pigs weaned/mated female/year ≥24 <21 Nonproductive sow days <70 >80 Culling rate 30–45% <30 and >50% Reproductive Benchmarking Indices Used in Swine Herds Reproductive Index Target Interference Level Wean-to-estrus interval (95% in estrus by 10 days postweaning) <7 days >10 days Repeat services at 21 (+/– 2) days <10% >17% Abnormal returns to service (25–37 days) <3% >5% Multiple matings >90% <85% Abortions <2% >3% Not-in-pig 1% 2.5% Farrowing rate >85% <80% Total piglets born/litter >11.5 <10.5 Live piglets born/litter 11–12 <10 Stillbirths <1% >3% Mummies <0.5% >1% Litter scatter (≤7 pigs/litter) <12% >15% Weaned/litter >9.5 <9 Preweaning mortality <12% >16% Litters/mated female/year >2.4 <2.2 Pigs weaned/mated female/year ≥24 <21 Nonproductive sow days <70 >80 Culling rate 30–45% <30 and >50%

Last full review/revision July 2011 by Gary C. Althouse, BS, DVM, MS, PhD, DACT