There are a whole host of infections within the sow herd. We devote most time to viral infections such as porcine reproductive and respiratory syndrome and swine influenza virus.
There are many common bacterial infections that may not cause large, whole herd losses like the viral pathogens. But they may cause major losses periodically — and if not addressed, can be quite costly to the sow herd.
Case Study No. 1
A 600-sow, farrow-to-feeder pig operation that farrows weekly, purchases replacement gilts at 40 lb., then raises them in an off-site finishing barn used for isolation and acclimation. Gilts are added to the breeding herd every 30 days and are bred on the second heat. Bred gilts are penned and hand fed to condition until farrowing.
The farm has experienced smaller gilts at farrowing that are less productive. Our recommendation was to increase gilt feed before and after breeding to insure adequate growth before farrowing.
Approximately four months after increasing gilt feed, the farm complained of poor feed consumption in farrowing and an increased incidence of mastitis in gilt litters.
We observed some gilts that had poor appetites, temperatures of 104 to 105° F and hard and swollen udders. The gilts were now bigger, but also appeared over-conditioned.
The producer had placed feeders in the gestation gilt pens, placing gilts on full feed for the last 70 to 80 days of gestation.
Our assessment was that this high level of feed intake was contributing to the edema. We recommended removing the self-feeders, returning to hand feeding and reducing the feed for gilts by 2 lb., seven days before moving to farrowing.
When gilts were moved into the crates, we recommended they be fed 3 to 4 lb., and made sure they were hungry when fed. The results were quite dramatic. Mastitis symptoms quickly disappeared and appetites postfarrowing returned to normal.
The lesson is don't overfeed gilts right before farrowing, as it will often lead to an increase in udder edema and poor-milking sows, and creates an environment where bacteria quickly multiply, causing infections, fever, pain and off-feed sows.
Overfeeding also reduces the ability of the gilt to nurse, resulting in fewer weaned pigs and poorer breed-back performance.
Case Study No. 2
A 1,500-sow, farrow-to-wean operation experienced chronic poor performance in the breeding barn. Farrowing rate over the last year averaged 78% with months at 65 to 70%. But farrowing rate dramatically decreased the last three months — 50% for some weeks with an average of 65%.
The farm breeds in crates with boar exposure in the front, and heat detection and breeding by staff as the boar moves through the area.
Uterine discharges also increased, 18 to 36 days following breeding. As we observed matings, it appeared that not enough attention was being paid to heat detection, and that many of the animals were being bred when they were not in a true standing heat.
We advised that for three weeks, the farm change the breeding flow so that sows are brought to a pen where the boar is crated, and then bred in an open pen. The intent was to increase the chances that if an insemination occurred in the pen, the sows would truly be in a standing heat. After three weeks of breeding in this manner, sow discharges decreased by nearly 80%. The 21-day return rate went from 30% to 15%. When these three weeks of breeding eventually made it into the farrowing rooms, their farrowing rate had improved to 82%, a dramatic improvement over the previous year.
Our assessment is that the sows were bred in the crate while they were not in true standing heat. If insemination is done when the uterus is not in a receptive state, it will frequently result in harmful bacteria being introduced and produce uterine infections and discharges. The improper timing resulted in a poorer conception rate as well as an increase in urogenital infections.
Paying closer attention to the signs of heat being exhibited by the sow will help insure that the timing is adequate to achieve an acceptable performance.
Even through the most diligent attempts to keep sows clean and the environment washed, resident bacteria exist, and given the right conditions and opportunity, will cause problems. Paying attention to detail and understanding the management and environmental conditions that can exist are important elements in evaluating solutions to profit-robbing infections.
Working closely with your herd veterinarian and allowing him/her to visit and observe the operation in action is often necessary in order to arrive at a final solution.