Breeding-Herd Synchronization Tools are Helping Producers Tighten Farrowing Windows, Reduce Lightweight Weans, and Improve Downstream Efficiency.

By Dr. Grant Weaver, DVM

Maximizing grow-finish throughput and efficiency is one of the main factors affecting the profitability of any modern swine operation¹.

Therefore, proper management and utilization of the breeding herd, which supplies the pigs and is the “engine”—so to speak—of the swine operation, is paramount in facilitating profitability.

One of the factors for success in the nursery-finish phase is the consistent supply of healthy pigs that are similar in body weight and age. Uniform initial body weights will improve marketing efficiency, and uniform age will aid in disease management and improve feed cost and performance.

Management factors can also play a major role in the promotion of group uniformity.

To facilitate the production of healthier and a higher number of weaned and feeder pig-sized pigs, batch farrowing has found a resurgence in the modern pork production arena^2,3.

A key to success in batch farrowing operations is groups of sows that farrow in tight time windows, since farrowing only occurs monthly or so rather than weekly. However, even in systems that farrow weekly, the tighter the farrowing time window, the more uniform the piglets will be in both age and size at birth and then weaning.

Proper nutrition and accurate and timely body condition scoring are important in making feed intake adjustments to ensure overall feed intake is optimal, which will lower post-weaning days to first service as a group⁴.

Herd health is always a top priority in helping the breeding herd to perform at its best.

• Proper vaccination schedules, treatment protocols, and overseeing farm personnel to make sure effective treatments are taking place all help to minimize the impact that disease has on weaned pig variability overall today.
• Establishing and monitoring biosecurity protocols are important in preventing disease entry on farms.
• Auditing and optimizing ventilation rates and maximizing the overall barn environment help to improve air quality, minimize the effects of disease, and improve production in general across systems.

Hormonal therapy can also be used to achieve a more synchronized farrowing process in swine. There are a few labeled therapies that are used to synchronize estrus, which subsequently leads to a more synchronized farrowing process.

One is a combination injectable product (P.G. 600, Merck Animal Health, Rahway, NJ) that contains the hormones Pregnant Mare Serum Gonadotropin (PMSG) and human Chorionic Gonadotropin (hCG) and acts to facilitate follicular growth on the ovary and then ovulation of the mature follicle.

Another is altrenogest, which is a progesterone analog and is administered orally to sexually mature gilts. Since it is a progesterone analog, this hormone mimics progesterone activity in the animal. Progesterone and its analogs extend the luteal phase of the estrous cycle, preventing the onset of estrus during the treatment period.

Upon removal of the treatment after 14 days, a high percentage of treated animals will show estrus within four to nine days of removal⁵. SwineMate, which is Aurora Pharmaceutical’s brand of altrenogest, was approved for use in the United States in 2017 and is a widely used gilt synchronization tool. It is a bioequivalent product to Merck’s Matrix, which was approved for use in the US market in 2003. Both products have been effective at improving reproductive efficiency on US swine farms since their introduction, especially in batch farrowing systems.

Below is a graph summarizing the estrous cycle of swine⁶.

Altrenogest works by extending the luteal phase during the time of treatment, in which a high level of the progesterone-like hormone is maintained (peaks naturally on day 12 of the cycle) and which prevents the FSH and LH surge the start on day 15 and 16 of the cycle, respectively.

Although only approved for use in gilts in the United States, altrenogest has also been shown to have a synchronization effect in multiparous animals⁷.

Also, triptorelin, which is a GnRH analog, has several advantages when used to assist the reproductive process in swine.

Triptorelin works by synchronizing ovulation in weaned sows and shortening the time from weaning to ovulation. It has been proven to facilitate the use of single, fixed-time artificial insemination, which can have the benefit of semen savings since only one insemination per breeding is necessary.

Also, there are potential labor savings due to a less intensive heat detection process⁸. By synchronizing ovulation in weaned sows, the farrowing process is shortened, leading to more uniform groups of weaned pigs.

Triptorelin has been shown to shorten the wean to ovulation window by seven hours in a group of sows when the product is administered at 96 hours post-weaning under supervision⁹.

Ovugel, which was marketed by United Animal Health since 2015 and is now marketed by Aurora Pharmaceutical, contains the active ingredient triptorelin. The product is in gel form and is labeled to be administered intra-vaginally.

Ovulation in swine occurs naturally over a longer range of time than in sows not treated with triptorelin¹⁰. Triptorelin acts to shorten that range, resulting in a more synchronized farrowing period. Ovulation will occur 40-48 hours after administration of the product when given 96 hours post-weaning in sows.

In addition to potential labor savings and more uniform groups of weaned pigs, probably the most overlooked and most significant potential benefit to Ovugel use is the production of fewer weaned pigs weighing less than nine pounds. Isoweans that are nine pounds or less are significantly less valuable in any market than animals that are above that weight.

One study showed that sows treated with Ovugel had slightly over 7% more sows farrow during the first three days of the week. If nursing piglets grow at .5 ADG or so, and seven litters out of 100 have an extra two to three days of life, then 85-90 piglets out of a group of 1,250 isoweans have an opportunity to be 1-1.5 pounds larger at weaning.

Since a higher percentage of less than nine-pound weaned pigs will come from sows that farrow later in the week, there is potential for a significant reduction in those.

DiPietre, et al showed a 1.87% decrease in the number of less than 8 lb. pigs at weaning and an increase in profit per litter of more than what the product costs today in finishing pig performance only in a farrow to finish operation under evaluation¹¹.

Studies that have been done with Ovugel and a single, fixed time artificial insemination have shown that treated animals have similar or better pigs born alive/litter and farrowing efficiency numbers compared to controls¹².

With recent cost reductions in the price of the product, one dose of Ovugel is now about one-half the cost of a dose of semen, so the potential for breeding cost savings is apparent.

Reproductive performance is similar in Ovugel-treated animals and controls when treated animals are exhibiting estrus¹³. Knox, et al showed that when triptorelin is administered upon the observance of estrus, a higher number of sows are inseminated within 24 hours pre-ovulation compared to non-treated controls and sows treated at 96 hours post-weaning¹⁴.

Insemination within 24 hours pre-ovulation is the main driver of conception rate and pigs born. Webel, et al showed that even when triptorelin is administered to animals in the breeding group that do not exhibit signs of estrus, total pigs born are higher for the group despite a lower traditional farrowing rate¹⁵. The table below illustrates that result¹⁶.

Some farms using post-cervical AI (PCAI) have found success with Ovugel since only one insemination is necessary instead of two. Because of that, there are some labor savings, and when those farms are using higher-cost semen, one less dose saves additional dollars.

Additionally, with batch-farrowing farms, the potential exists for lower cull rates since there are fewer late farrowing animals.

It makes sense for producers to use every technology available that provides economic return and improves pig quality. Since not all farms are the same, it may be necessary to tailor a breeding enhancement program to best fit your farm. Technology continues to provide farms with options to improve profitability.

References

1. Bilbrey, Greg. (2012). Key factors affecting profitability of swine production companies. Allen D. Leman Swine Conference, vol. 39, p. 241.

2. Four Star Veterinary Service, Oct. 25, 2019, Batch farrowing benefits Indiana hog operation, www.4starvets.com, News, p.8.

3. Swine Vet Center, April 6, 2020, Batch farrowing makes a comeback on small-to medium-sized farms, www.swinevetcenter.com

4. Bates, Ronald. July 14, 2011, Sow body condition influences productivity and profitability, Michigan State University Extension, https://extension.msu.edu/ newsletters

5. Aurora Pharmaceutical, Inc. SwineMate (altrenogest), 2026, https://aurorapharmaceutical. com/species/porcine/estrus-management/swinemate-altrenogest

6. Safranski, Timothy J., Cox, Nancy M. Clinical Reproductive Physiology and Endocrinology of Sows-Mating Management. Veterian Key, September 3, 2016, Chapter 98. www. veteriankey.com

7. Liu, Kexiong,et al. Effect of altrenogest treatment before weaning on reproductive performance and production efficiency in primiparous and multiparous sows. Porcine Health Manag. 2024, July 6;10:25. DOI: 10.1186/s40813-024-00377-7

8.,9.,10.,13.,14. Knox, R.V., et al(2011). Synchronization of ovulation and fertility in weaned sows treated with intravaginal triptorelin is influenced by timing of administration and follicle size. Theriogenology, 75, 308-319.

11. DiPietre, et al(2017). The Economic Impact of Ovugel®. American Association of Swine Veterinarians Proceedings, pp. 220-224.

12.,15.,16. Webel, Stephen, et al(2013). Effectiveness of Ovugel® in commercial swine herds in the United States. American Association of Swine Veterinarians Proceedings, pp. 119-122.

Dr. Grant Weaver, DVM
Aurora Pharmaceutical

Dr. Grant Weaver, DVM, graduated from the Iowa State University College of Veterinary Medicine in 1989. Dr. Weaver went on to work in private practice for more than two decades, spending the majority of that time in rural Northwest Iowa. In 2012, Dr. Weaver shifted his career to industry, receiving his EVP program certificate from the University of Illinois in 2016. Currently Dr. Weaver is employed at Aurora Pharmaceutical, Inc. where he is the Food Animal Technical Service Veterinarian, a role he has held since 2019.