Find Problems Faster with Proper Use of Records
Use breeding herd records to diagnose reproductive disorders.
By Michelle Sprague
Breeding herd records are central to our industry and our daily lives. As the old adage goes, "You can't manage what you can't measure." Record systems help producers track every possible production parameter in an effort to measure, monitor and, ultimately, manage these parameters.
Routine surveillance of production records can help identify aberrations before they become clinically obvious (or at least obvious enough to warrant a phone call to the veterinarian). These observations may not point to a health or production concern, but warrant investigation.
For the purposes of this article, let's assume that all production-record information is accurate. Of course, in the real world, that is one variable that must be verified. Special instructions are often necessary when asking farm employees to correctly classify mummified and stillborn fetuses. Likewise, pregnancy-rate reports are only as good as a breeding technician's ability to detect estrus and confirm pregnancy. When assessing records, remember the constraints of each particular data system and that the data generated is only as accurate as the information that is entered.
Monitor key breaeding parameters
Farrowing rate serves as a barometer for reproductive issues, or lack thereof, in a herd. Decreased farrowing rate can be an indicator of many causes of reproductive disorders. To more accurately depict the clinical picture, one should assess conception rate and wean-to-first service interval.
Most production data systems can generate reports that categorize returns as regular or irregular, which can be helpful in troubleshooting reproductive problems. Analysis of a farrowing-rate report is beneficial in determining the time at which females are identified as not pregnant. This can assist in ruling some causes of reproductive failure into or out of the list of differential diagnoses. All of these reports can bring added value when run by parity.
If average conception rate is poor, management t issues are more likely the culprit than health concerns. Some key factors that may play a causative role include poor semen quality, inappropriate semen handling, inadequate estrus detection (including boar exposure), improper insemination technique, incorrect timing of insemination and moving (or other wise stressing) sows during the period of implantation. Most of these situations will result in a regular return to estrus and will be reflected on the farrowing rate report as a higher-than-normal number of females falling out of their cohort group at three to four weeks post-insemination.
Investigation of poor conception rates often points to semen not being handled appropriately. Stray voltage also can cause reproductive losses; upon in-depth investigation of poor fertility rates, stray voltage has been identified as the cause for reproductive losses in two herds within our system. In addition, inadequate stall acclimation and/or lack of heat-no-service to gilts has been identified as a cause of inferior gilt conception rates.
Review historical records
Looking at reports year-over-year can be helpful in diagnosing seasonal infertility. Some sow farms seem to be more affected by seasonal fertility than others. Also, some pure-line females tend to experience seasonal infertility to a greater degree than most crossbred dam lines. Running reports and analyzing seasonal trends over several years can help confirm seasonal infertility as a routine problem.
In a direct quote, Dr. Juan Lubroth, FAO chief veterinary officer, said "The current FMD dynamics in eastern Asia, as well as the magnitude of the outbreak in South and North Korea, are unlike anything that we've seen for at least a century." As of April 4, 2011, over 33 percent of all South Korean pigs have been culled.
Consider other factors
Other circumstances that may result in low conception rates include poor body condition, short lactation length, low lactation feed intake, small litter size and low suckling intensity of recently weaned piglets. These situations sometimes result in low ovulation rates and, depending upon the number of ova fertilized, could result in a regular or irregular return to estrus. Because of a low ovulation rate, litter size will likely be compromised on the affected sows that actually do farrow.
Lactation length has been increased on a number of farms in the AMVC system through the addition of farrowing rooms in an effort to improve performance, both at the sow farm and in the wean-to-finish flow. These efforts have been met with success, resulting in higher farrowing rates and more piglets born alive per litter in every instance.
If conception rates are normal and/or returns are irregular, health concerns are higher on the list of differential diagnoses. Common infectious agents include porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus and porcine circovirus type 2 (PCV2).Bacterial agents also may play a role, though infectious causes of reproductive disorders are far more frequently viral in nature than bacterial. Viral and bacterial diseases may affect the dam or the fetuses and may or may not be associated with abortions.
When the incidence of abortions increases, diagnostics are in order. PRRSV is the most common culprit in our system, but swine influenza virus (SIV) and mycotoxin contamination of feed have also been diagnosed.
Key farrowing parameters to monitor
As previously mentioned, the number of total born and, subsequently, born alive may be impacted by various factors that cause a low ovulation rate. Additionally, factors that cause early embryonic death may result in absorption of some fetuses, while others are unaffected. In these situations, the number of born alive will also be lower than normal.
The number of mummified and stillborn fetuses can provide good information to aid in diagnosing reproductive disorders. Mummies are reflective of fetal death through mid- to late-gestation. There are a variety of potential causes of such losses, but viral infection is the most common.1
Pay attention to timing of vaccination and controlled oral exposure. This has been the cause of increased mummy rates more than once. Also, inadequate exposure of gilts to organisms that are resident in the sow herd can result in increased mummy rates on gilt litters.
Presence of stillborn piglets may or may not be an indicator of reproductive problems. A low number of stillborns may merely be reflective of large litter size, birth order and/or prolonged farrowing. When coupled with the presence of mummies, however, stillborns may have more diagnostic value, as the likelihood of disease is increased.1
Putting it all together
Record systems that are in place today make it simple to compile and analyze data. While one performance parameter may point to a reproductive disorder, looking at a combination of different factors helps narrow the list of differential diagnoses. Once the list of differentials is generated from the clinical picture and the performance records, one must use other resources to further characterize the etiology. One must investigate a number of factors, including quality of water, air and environment, vaccination procedures, semen handling and breeding techniques for valuable insight. Other things to consider include diagnostic tests for pathogens and feed analysis for vitamins, minerals and mycotoxins.
Remember, your records are only as good as the data entered. Play close attention to accuracy, then use the information gathered to monitor previous production to make future improvements
Editor's Note:Michelle Sprague, DVM, is director of sow farm health management at AMVC LLC in
Audubon, Iowa. This article was originally published in the 42nd Annual AASV Meeting proceedings