Moving Closer to 1-Dose Insemination Schedules

Biological variation is one of the most significant factors in determining the number of doses required per service in today’s commercial swine herds. In an ideal situation, where the precise time of ovulation is known, a single properly timed insemination would be sufficient to achieve successful farrowing rates and litter size. The ideal insemination time is twelve hours before ovulation occurs. Upon insemination, the semen requires 12 hours for capacitation. Capacitation is the change which occurs in the sperm cell that allows it to penetrate the ova for fertilization.

Single dose insemination technologies are being developed. In the meantime, we can reduce biological variation and fine tune current insemination schedules through better management to prepare for these new technologies.

Better Management

Recent research from the University of Missouri in Columbia, has found several management factors that can cause variation in the weaning to ovulation interval, which is more constant than the wean to service interval. The factors considered in this research included sow body condition, parity, and lactation length. Investigators found that as body condition score, parity, and lactation length became more uniform, the wean to ovulation interval decreased. Overall the animals involved in the study had an average wean to ovulation interval of 178.22 ± 63.71 hours.

SOW BODY CONDITION - In addition to overall reproductive performance, body condition has a significant effect on the wean to ovulation interval and the resulting variation. The extreme body conditions both too thin and too heavy had greater variation. The ideal body condition is either a score of two or three on a scale one to four. The variation of the ideal body condition is approximately eleven hours. Thin or under-conditioned sows had over a seventeen-hour variation, and over-conditioned sows had a variation of over 35 hours. With this in mind, it is easy to see why having uniform body condition in a sow herd can greatly improve both reproductive and economic performance.

PARITY DISTRIBUTION - The Closed Herd Internal Multiplication System is designed to prevent a herd’s parity distribution from becoming too varied by having a constant supply of breeding age gilts. The suggested sow replacement rate is 50% annually. This should keep the average parity at approximately 3 with a range of 1 to 5. After the fifth parity, sows tend to have longer wean to service and wean to ovulation intervals. The wider the parity distribution, the more variation that is created, thus a greater need for multiple dose breeding schedules.

LACTATION LENGTH - Another key management factor is lactation length. With the availability of AI, parturition induction, and weaning technologies, variation in lactation length can be kept to a minimum. Ideally, all sows within a group should have the same lactation length. Practically speaking, most producers are able to reduce this variation to three or four days. When these sows are sent to breeding, they will return to estrus more uniformly. Gilts should be introduced and managed so that they cycle at the same time as the weaned sows.

Improved Technology

As with most emerging technologies, the most limiting factor initially is the economic viability of the technology. The first uses of these new technologies will be for research and development. For example, German researchers, with the aid of ultrasound technology, have been able to use a single dose inseminated 12 hours before an estimated ovulation time based on follicular growth. To date, most single dose breeding schedules have been done with the assistance of ultra sound technologies, which are used to monitor follicle growth on the ovaries. There has also been some work done with electroconductivity of vaginal secretions during the estrus period. Most of these technologies will be developed and available for use at the commercial level.

Another key factor in moving toward one-dose technology is extender. Extenders are constantly being improved to allow for longer shelf life, longer life in utero, and better protective capabilities. As new extenders are developed and proven repeatedly through good research both in the lab and in the field, they will be implemented into Babcock’s stud program.

Summary

Until the new one-dose technologies are proven and economical, directing management efforts toward the reduction of biological variation will allow most producers to move from three dose schedules to two dose schedules. This way, as one-dose technology becomes available, your herd’s biological variation has already been minimized as much as possible.