Replacement Rates: Successful or Not


By Dr. Tom Gillespie

“Our persuasion about change impacts many aspects of our lives. It affects our perception of risk and thus guides most business and personal decisions. Further, our persuasion about change affects our ability to persuade others, to impact the lives of our clients and our communities, and to affect the course of change,” said Dr. Dave Reeves, BS, MS, DVM, Associate Professor Emeritus.

Benchmarking implications

Benchmarks in our industry are widely available from several sources, including magazines, neighboring producers, accountants, other professionals, etc. However, the act of benchmarking – the active process of improvement through the use of benchmarks – is more difficult.

Historically, producers and veterinarians have been persuaded by records to make changes in techniques to achieve better production. Constraints are present in every swine facility due to how the site was constructed, in terms of animal flow – which can also influence reproductive performance.

Producers are overcoming some constraints through improved management technologies, such as one continuous “snake” in gestation/breeding, post cervical artificial insemination (PCAI) versus regular AI, etc. Occasionally, producers cannot completely overcome a constraint and face limitations in the particular production parameter that is most affected.

PigCHAMP’s annual Benchmark magazine has been a wonderful resource for information and education for several years. Participants in the benchmarking program are producers that share their production information.

The participants can request customized reports, although PigCHAMP shares a routine quarterly report with each participant. This report details how the farmer’s production benchmarks with averages of the entire PigCHAMP Benchmark data.

Before we take a look at the collective production parameters for 2016, we need to understand a couple of points. The challenge of comparing one’s production records to a larger group has a fallacy – what holds true at the group level may not hold true on the individual farm level. Furthermore, what holds true at the group level may not even be feasible at the individual level or system, given the specific facilities’ defined constraints. So the benchmarking results need to be relevant and/or refuted by applied research.

Another challenge with contemporary industry benchmarking lies in statistical understanding. Under normal circumstances, half of the farms are expected to be above average, while half are expected to be below average – some for good reasons and others just by chance. Improperly used, benchmarks can be demoralizing agents rather than means to establish expectations.

The added use of statistical process control (SPC) charting, which I discussed in my 2012 Benchmark article, has been an outstanding tool to better understand biologic variation on a given production parameter. The goal in benchmarking one’s production is to first have an open mind that change may be necessary to move to a more efficient level. A second goal is permitting in-depth evaluation of the necessary changes that are needed to make the modification. A third goal in benchmarking is to develop the leadership skills to advance the team’s approach through proper communication and new training for the staff.

One of the more important management decisions driving the sow herd productivity and performance is the gilt introduction, development and management program. Large variation exists with respect to the successful introduction and retention of high value replacement gilts in the herd.1 A common “goal” for most sow farms is to cull and replace approximately 50 per cent of the females per year. The farm staff need to be aware of “premature” culling of young females.

Culling rate comparison of the last three years

Culling rate comparison of the last three years

Several publications have shown that nearly 20 per cent of premature culling of females from the breeding herd occurs for parity 0. In addition, 65 per cent of these culls are attributed to reproductive disorders or failure. 2,3,4,5

Management teams on all sow farms should develop practices that produce gilts with the greatest potential lifetime performance. Even minor improvements in gilt management can lead to major increases in breeding herd efficiency. PigCHAMP data for 2006, for example, showed that on larger breeding sow farms in the United States and Canada, annual herd replacement rates were often between 60 and 70 per cent, with a number of important consequences:

  • A larger pool of replacement gilts is needed to meet increased replacement requirements.

  • Suboptimal gilts are bred to meet breeding targets; they have lower performance and will be prematurely culled.

  • Breeding herd parity distribution is unstable and biased towards lower parity females.

  • Chronic over-crowding of pens in the gilt development area is needed to meet replacement needs.

  • Negative impacts on health and welfare influence poor gilt growth, which can relate to the onset of delayed first time estrus and possibly less than desired parity one performance.

  • Pressure to meet breeding targets results in less fertile gilts being bred using pharmacological interventions.

  • Gilts are bred below target weights.

  • General performance and morale of gilt development unit (GDU) staff declines and staff retention is low.

The benchmarking summaries for the past three years show a replacement rate ranging from 42 per cent to nearly 70 per cent. These statistics demonstrate that some farms continue to replace gilts at a high rate.

Dr. John W. Mabry reminded the attendees at the 2017 annual meeting of the American Association of Swine Veterinarians (AASV) that there are costs to procure replacement gilts, even if internally produced or purchased. The key point here is that all replacement gilts come with a “cost.” The decision to insert replacement gilts at high rates may be logical in some operations – just be sure this decision is based on a thorough economic analysis.


The successful introduction and retention of gilts through the early parities drives the success of all sow herds, and promotes lifetime production. Modern producing females and management teams can face challenges in achieving outstanding production, with the facility layout being one constraint. Sow farm personnel have made facility layout adjustments that allow replacement gilts to respond with amazing levels of pigs born and weaned per female.

A sow farms’ goal is to produce the desired number of high value weaned piglets at each weaning, whether weekly or by batch.


  1. Culbertson, M. 2008. Measures of lifetime sow performance. In: 2008 Swine Breeding Management Workshop: Setting up the Breeding Herd, University of Minnesota, St. Paul, United States.
  2. Lucia, T.L., G.D. Dial, W.E. Marsh. 2000. Lifetime reproductive performance in female pigs having distinct reasons for removal. Livestock Production Science 63:213–222.
  3. PigCHAMP. Benchmarking. Available on: http://www.pigchamp. com/benchmarking. Accessed August 2009.
  4. Gill, P. 2007. Nutritional management of the gilt for lifetime productivity – feeding for fitness or fatness? In: London Swine Conference 2007, Ontario Ministry of Agriculture, Food and Rural Affairs, London, Ont., Canada.
  5. Engblom, L., N. Lundehei, E. Standberg, M. del P. Schneider, A-M. Dalin K. Andersson. 2008. Factors affecting length of productive life in Swedish commercial sows. J Anim. Sci. 86:432–441.

Tom Gillespie, Rensselaer Swine Services, P.C.
Tom Gillespie is the owner and founder of Rensselaer Swine Services, P.C. He is a diplomate in the American Board of Veterinary Practitioners, Swine Health and Management Specialty. Gillespie consults, lectures and provides training in key swine producing countries around the world.

Bethany Animal Hospital and Rensselaer Swine Service veterinarians strive to improve services to all clients through specializing in different fields of interest and offering support staff for special projects, benchmarking production and market information.