A successful breeding program justifies the time and effort needed to start and maintain a gilt development scheme, says an Iowa sow farm manager who has compiled excellent five-year gilt production data.
Maple Grove Pork Co. manager Karl Glaspie is never satisfied with overall herd performance.
But even he admits the five-year gilt production figures that the sow cooperative has amassed since its start in 1998 are hard to beat — especially when you consider the herd has dealt twice with porcine reproductive and respiratory syndrome (PRRS) outbreaks.
Key gilt production figures include:
Adjusted farrowing rate of 85.8%;
Total born average of 12.5 pigs/litter;
Live born average of 11 pigs/litter;
Weaned pig average of 9.6 pigs/litter, and
An average of 92.5% of first-parity sows rebred within seven days.
“To me, with a five-year average of almost an 86% farrowing rate on gilts, since we started breeding gilts on Day 1 of the operation, we can justify spending time and money on gilt development,” says Glaspie.
Keys to Success
To achieve that level of reproductive success, Glaspie and owners instituted a series of detailed protocols that are closely followed by the North English, IA, 2,400-sow, breed-to-wean operation.
“We sit down with our veterinarian, Rex Greiner of Keota (IA), and decide what the protocol on incoming gilts should be, and he turns around and does a vet-to-vet consultation with the supplier,” Glaspie says.
“I am very particular about health concerns. There are certain things that the gilts are supposed to be free of, but we have our own criteria that they have to meet, too,” he states.
On arrival, gilt replacements must be guaranteed free of what he terms the “big three,” Mycoplasmal pneumonia, PRRS and pseudorabies (PRV). “The gilts are bled at the supplying herd, and I also bleed a random sample of the incoming gilts from that herd and send them to our veterinarian for verification,” he says.
Swine influenza virus (SIV) is a fourth disease of concern. Titers are checked on arrival, and rechecked when gilts move to the sow herd. Titers reflect the amount of antibodies circulating in the gilt's bloodstream.
Glaspie is a stickler in only accepting gilts delivered 100% as promised. Potential replacements with soundness problems, poor underlines, open wounds or tail biters will be immediately culled and shipped. Sometimes the cull rate on a group of gilts can be up to 17%.
He declares: “There have been times when I have rejected some animals, and I haven't had enough to bring into my sow herd. But why do I want to drop my production level because I didn't get the quality gilts that I want?”
He has also warned his supplier he will no longer take overweight gilts because they end up being unproductive sows.
Sometimes Glaspie's strict policies on gilt culling are an inconvenience. But, he adds, it cuts down on downer sows and sow mortalities.
Treating Gilt Arrivals
From 360 to 370 gilts arrive every quarter in two separate shipments, usually hours apart. One group of gilts averages 180 lb., the other 210 lb. By having staggered weight groups, all gilts can be processed through the mandatory 75 days of isolation and acclimation without getting too heavy, observes Glaspie. And, that provides enough gilts to breed for three months. One side of the barn is designated for the smaller gilts, the other side for the larger gilts.
During the first 30 days or so in isolation, gilts will be given two vaccinations for Haemophilus parasuis; two combination injections for PRV, parvovirus, leptospirosis and erysipelas; two combination vaccinations for SIV, mycoplasma and erysipelas; two vaccinations for PRRS; and two wormings for internal parasites.
When Maple Grove Pork was established in 1998, it was stocked with PRRS-positive animals and the herd remains positive.
“A lot of veterinarians ask why we ‘shoot’ negative animals (gilts) with PRRS. We have been doing it since Day 1. We have had two PRRS breaks, in March 2000 and in December 2002, but they were smaller outbreaks. The virus hasn't caused us a great amount of problems, and we feel vaccine is doing our herd some good,” emphasizes Glaspie.
When gilts move to the breeding barn, they get a booster shot for parvovirus, because the operation had a health issue with parvovirus about a year ago, says Glaspie.
The main sow herd only receives quarterly vaccinations. On Jan. 1 and July 1, they are vaccinated with the combination product that includes PRV, parvovirus, leptospirois and erysipelas. On April 1 and Oct. 1, sows are vaccinated for PRV only.
Antibiotics are only used to treat sick, lame or off-feed animals. The exceptions are tylosin, fed at a low level to all gilts for ileitis prevention, and chlortetracycline, fed to sows for health maintenance, he says.
Incoming gilts are not placed on a finishing-type ration, Glaspie stresses. They are full fed (6-8 lb./day) a denser ration, highly fortified with calcium, phosphorus and lysine to aid bone growth and development to maturity.
If gilts start to grow too large in the developer unit, their rations are supplemented with oat pellets.
“Oat pellets are a fiber source that makes gilts consume the same amount of feed, but provides them with less energy, slows weight gain, but still helps develop bone structure,” says Glaspie.
For acclimation, two weeks after placement, placentas and mummies from the farrowing house are ground up and mixed in the feed and fed to the new gilts. This is done two to three times a week. Any scours in farrowing is also mixed in.
Feedback is also practiced daily for sows in gestation to build immunity.
Cull sows and boars are rotated to acclimate new gilts, explains Glaspie. A group of 3-4 cull sows walk the 30-in. center alley, providing nose-to-nose contact with gilts for 24 hours. Cull sows are then penned and a cull boar walks the alley for 24 hours.
“We don't put the cull sows in the pens with the gilts, which is highly recommended, because the cull sows will get picked on,” he points out.
Glaspie tries to select cull sows with a fever or that have been sick recently “to expose gilts to anything that we have in our sow herd.”
Acclimation continues when gilts enter the breeding herd. Gilts are brought into the breeding barn in staggered fashion, 75 at a time to fill a special row of crates to help them become accustomed to gestation crates. They are exposed to boars morning and night; heat cycles are recorded until they are bred. He emphasizes new gilts won't be bred for three weeks or until completion of a heat cycle.
“We bring them in at different times, because we don't want all 360 of them to come into heat at the same time, and then have no gilts to breed in certain weeks,” explains Glaspie.
Because different sets of gilts are being brought in and coming into heat all the time, it allows staff to select gilts in the best condition and in optimum standing heat to be breed.
Staggering gilt introductions improves reproductive success because it permits staff to only breed a few gilts at a time to meet the goal of 22-25 gilts bred per week, he says.
In addition, breeding is separated to ease the pressure on staff, he adds. Sows are bred by 10 a.m. Staff tend to other chores for a few hours, catching a break. Gilts are bred at 3 p.m.
Gilts and sows are mostly bred artificially, but 50 boars are kept on hand to breed those that recycle and for heat detection.
Successful gilt development and breeding carries over into the sow herd, currently maintaining over a 25 pigs/sow/year average.
Glaspie is reluctant to mention that figure, because he believes the herd can do better.
Glaspie Defends On-Site Gilt Pool
Having the gilt developer barn off-site might seem ideal, but Maple Grove Pork Co. has found that their on-site gilt barn works just fine.
The gilt barn, gestation, breeding and farrowing units are all attached, connected to each other by 50-ft. enclosed walkways.
A 40×90-ft. gilt barn was built in 1998, recalls Glaspie. Gilts got 10 sq. ft. Two years ago, the double-curtain-sided barn was extended to 40×120 ft., to improve gilt comfort, freedom and flexibility. Space expanded to 12 sq. ft./gilt.
Building the gilt developer on-site actually holds more pluses than minuses, he asserts. You can do a better job of acclimating gilts, while still protecting them from possibly exposing the sow herd to new pathogens, by instructing employees to work the gilt barn at the end of the day.
Staff are advised not to shower nor change clothes before entering the gilt developer. This offers another way to expose gilts to any infectious organisms in the breeding herd, states Glaspie.
An on-site gilt unit also lessens the amount of labor needed, compared to traveling to and from an off-site gilt unit once a day.
Sow Herd Protection
The sow herd is physically protected from incoming gilts in several ways.
The door connecting the gilt barn to the breeding barn is kept locked to keep gilts from being added prematurely. It is also completely taped to stop air from being sucked down the connecting hallway between gilt and sow barns.
All barns except the gilt unit have solid sides. Those barns have shallow, 2-ft. manure pits, which feature pull-plug flush systems. These pits are flushed into the first-stage settling basin and buildings are recharged from the second-stage lagoon about every two weeks, explains Glaspie.
The gilt barn has a self-contained, 8-ft.-deep manure pit. Once a year, manure is direct-applied from the gilt barn pit to area fields using a dragline hose application system, always after effluent from the other barns is field-applied, to avoid any cross-contamination.
“We don't want manure from the gilt barn interchanging with any of the other manure since this operation utilizes a flush-recycle system, and there is always the chance of a bug like porcine reproductive and respiratory syndrome living through this manure,” he says.
The 12 owners of the cooperative venture carefully scoured central Iowa before deciding on an isolated, 20-acre site about five miles west of North English, IA. A nice grove of trees borders the site, blunting the effects of aerosol transmission. The nearest hog farm is about four miles away.
Protection is afforded by signs at the main gate, which is closed and locked at night, warning visitors not to proceed beyond the main entryway at the first building. The entryway is the only unlocked door on the site during the day, providing access to a restroom. All other doors are locked 24 hours a day.
Bait boxes are used around all building perimeters to ward off rats and mice.
The curtained gilt barn is screened to keep out birds and other varmints.
The site is shower-in, shower-out. Visitors must be away from hogs for a minimum of 48 hours to visit Maple Grove Pork, says Glaspie. That rule includes the owners.
Owners receive 11-lb.-plus weaned pigs to finish out on their farms. All pigs are fed out on owner farms; there are no outside investors in the company, stresses Glaspie.