There are many factors that lead to the success or failure of reproductive efficiency within the breeding herd. When faced with reproductive challenges, be sure to examine all possible inputs thoroughly.
Case Study No. 1
A 1,200-sow, farrow-to-wean producer has experienced a consistently high rate of returns to estrus, around 20-30%, and poor farrowing rates.
As we reviewed the producer's PigCHAMP records, different items began to pop out. The multiple matings report was consistently 100% across all parities each week. Wean-to-estrus interval on the farm was lower than many farms we service.
Some recycles were found during 21-day heat checks, but most were found when females were checked for pregnancy. Semen usage was tracked, and it became apparent that 50% or more of the sows weaned on Thursday were being bred the following Monday. Don Levis at Ohio State University indicated that, based on Thursday weanings, only 10-15% of the sows should be bred on Monday. Another interesting twist was that this farm was trying to control costs by limiting semen usage to two matings per sow.
Observations at the farm revealed these concerns:
Matings took 30-50% less time than at other, similar farms.
The primary breeding technician was “rushing” semen intake by squeezing tubes.
When our observations were done on a Monday, it appeared that many sows weren't responsive to boar and heat stimulation. The technician admitted the sows would likely stand better on Tuesday.
Temperature recordings of the semen cooler were kept daily. But when temperatures were 10° off set point, it was over a week before the owner of the facility was notified.
Heat-checking procedures were performed rapidly with one technician in front of the sow walking the boar, and no one walking behind the sow.
We felt the breeding technician was being overzealous in mating sows on Monday, so we made these adjustments:
Temporarily, no Monday breedings were allowed.
Sows that were in heat or showing signs of coming into heat on Monday were marked, then bred on Tuesday and Wednesday. Sows showing the first signs of heat on Tuesday were marked and bred on Wednesday and Thursday.
Any sows coming into heat Wednesday, or later in the week, were bred on that day and the following day.
Technicians were “re-taught” not to “squeeze” semen through the spirette, and instead reminded to allow a slow uptake of semen.
Heat check personnel were instructed to work in pairs — one person in front of the boar and one behind the sow. They also needed to “slow down” the process of heat-checking sows, especially at 21 days.
Semen cooler temperatures were recorded, and the owner notified right away of more than a two-degree variance from the set point.
We are still early in monitoring the results of our changes. To date, though, the rate of return to estrus is down 10-15%. We believe we are getting semen in the sow more closely to her natural ovulation, and we appear to be picking up a greater number of sows at 21-day heat checks, rather than relying on pregnancy detection.
Case Study No. 2
A 150-sow pasture farrower reported high pig death loss and poor-milking sows. This farm batch-farrows spring and fall, utilizing huts on clean pastures. During our herd visit, temperature and humidity conditions were optimum for farrowing. Sows were in good condition.
Oddly enough, sows and gilts that had farrowed three weeks earlier, were nursing healthy litters. The sows we observed had absolutely no udder and all necropsied pigs had empty stomachs.
Tissues from necropsied pigs yielded a variety of bacteria, which we felt were secondary to malnutrition. Sow feed samples indicated low-protein levels.
The producer called two days after our visit, revealing that non-milking sows had all been vaccinated at five days or less prefarrowing. All sows were receiving an E. coli/Clostridium perfringens product, were vaccinated for swine influenza virus, and had received an injectable product for internal and external parasites.
After vaccination, no sows showed any adverse reactions such as abortions or going off feed. The producers noted all sows at six days or more following vaccination were milking fine.
We concluded the low-protein feed, and injection of multiple products so close to farrowing (<5 days) interfered with the sow's normal hormonal influence and milk letdown.
When you are faced with reproductive challenges, consult with your veterinarian, be thorough and leave no stones unturned.