To solve depressed farrowing rates, most times you've got to take action in several areas of the breeding herd.
Using a combination of diagnostic serology, evaluation of records and effectively following breeding herd programs, you can boost farrowing rates, sow performance and pig numbers out the door.
That's the view of Mark Hammer, DVM, who oversees 40 farms of Carroll's Foods of Virginia.
Diagnostic Serology, Records One of the toughest questions related to low farrowing rates is whether the problem is due to disease, management or both, states Hammer.
The fact is, they often overlap. Using both diagnostic tools and a records program, managers can identify and treat major diseases and make the management changes needed to improve a low farrowing rate, he says.
In the closed production system at Carroll's, serology tests uncovered three major diseases: Porcine Reproductive and Respiratory Syndrome (PRRS), swine influenza virus (SIV) and leptospirosis.
For PRRS, a gilt vaccination program coupled with proper isolation and acclimation of incoming breeding stock was instituted. Gilts were vaccinated up to three times before entering the breeding herd, says Hammer. The vaccination program in particular has been very costly. But so is uncontrolled PRRS, and its affect on farrowing rates and pig production. And the treatment program, using a modified-live-virus PRRS vaccine, has been very effective in maintaining herd stability for PRRS for three years, stresses Hammer.
It appears now that SIV started with an outbreak in a multiplication system. But before it was recognized, it swept through that whole multiplication system. Conception rates fell to 35-40% in some parts of the system, he recalls. Records showed a rise in irregular returns to estrus from first to second heat periods.
"The animals were conceiving but they were falling out as a group," explains Hammer. A sow vaccination program for SIV (H1N1) was started. Performance bounced back in just 6-8 weeks. The commercially available SIV vaccine is designed to provide uniform gilt protection and maintain sow immunity through vaccination at weaning, he adds.
Because PRRS was uncontrolled before vaccine and management steps were introduced, leptospirosis (bratislava and pomona) problems had to be addressed. Two steps were taken. First, a bratislava vaccine program began. Second, an antibiotic was added to the sow feed to deal with pomona. The protocol for six months was to add and remove chlortetracyline (CTC) in two-week intervals.
"It looks like it has improved conception rates," observes Hammer. Internal research suggests CTC improves conception rates 3-5%.
"That was good enough for me and I started adding CTC throughout the whole system and it has paid off," he says. During the protocol, CTC was fed at 400 grams per ton in lactation and gestation rations. Use of CTC continues in a strategic fashion to medicate for leptospirosis.
Once major diseases are under control and if there is still a conception/low farrowing-rate problem, check the wean-to-service interval and repeat-breeding report. These reports will lead one to other areas within the breeding herd to intervene. Wean-to-service averages 5-6 days for normal farrowing groups.
Feeding Sows Longer wean-to-service interval indicates a lactation intake problem. Hammer suggests that once it's determined the sow rations are properly formulated, look at sow feed intake.
There are two major reasons for underfed sows in Carroll's operations in the Southeast: over-heated sows and sows not offered enough feed, says Hammer.
Sows will get hot in farrowing barns as temperatures hit 95-100 degrees F outside, says Hammer. "You can't keep them cool all day. They are going to get hot at some point. The thing I tell my managers is, I don't want that animal to get hot until 4-5 p.m.," he says.
Managers need to check sows and adjust the ventilation system as needed.
Don't gauge sow comfort based on outside temperature. Check respiration rates. "If I go into a farrowing house at 10 a.m. and sows have respiration rates about 40 (breaths per minute), that's too high. We get tunnel vision on temperature. Even if it's 80 degrees F outside, if you get sows with respiration rates about 40, that's too high," points out Hammer. Train people to evaluate the farrowing house based on the sow and piglet comfort, not only the temperature.
Feeding lactating sows ad lib means providing as much feed as they will eat. The industry is doing a poor job of meeting this challenge, he charges. "If you go into a farrowing house three hours after sows are fed and all the feeder pans are empty, that is not ad lib feeding," he says.
Monitoring lactation feeding levels is an important management job. Feed usage can best be checked by monitoring amount of lactation feed delivered to the feeders and sow feed consumption cards. The cards are a training device which helps management gauge staff's ability to feed sows. Breeding Details Breeding reports can help evaluate heat check efficiency. Watch to make sure estrus ratios are normal for first estrus (18-21 days post-breeding) and second estrus (36-42 days post-breeding), says Hammer.
Give the boars enough time with the females to stimulate expression of estrus. Even with artificial insemination (AI), boar exposure is vital, he stresses. Fence-line contact is a good way to provide increased exposure.
Hammer stresses the industry needs to take a different look at the AI programs. "Routine monitoring by management of the entire AI process is required for consistent breeding herd output." He divides that monitoring into the following areas: semen handling, breeding stimulation (see Table 1), AI technique, breeding schedule and breeder training. The system was devised by Carroll's employee Roger Nelson.
Semen handling extends from collection to insemination. For the producer, delivery, on-farm storage and insemination are three keys to an AI breeding program, observes Hammer.
"Delivery is extremely critical," he declares. "If the personnel are not close at hand when that semen is delivered, it's a potential time for that semen to warm up and the producer could have problems with semen viability." Delivery-to-use problems are common. "Semen may sit for 2-3 days on that farm before it is used. Has it been handled right since it was dropped off? Is it picked up and put in a safe place quickly? If not, that can be a special problem area," he points out.
Maintaining temperature control, delivering proper nutrients to the semen during storage and reduction of bacterial contamination are the biggest factors affecting semen quality during storage time, stresses Hammer.
"Basically, that box we are storing all the boar semen in needs to be looked at as all the boars on the farm," he says. "When you are doing 100% AI, that's where all of your boars are. You should be checking the temperature of the semen several times a day to make sure it is not below 60 degrees F or above 70 degrees F.
Swirl semen three times a day to remove waste products and deliver fresh nutrients. A proper rocking technique of the container must be employed.
Make sure employees understand breeding stimulation and insemination techniques. One way Hammer advises to maintain breeding performance is through quarterly evaluation of efficiency. Operator efficiency is defined as the number of sows serviced by one person, divided by the number of sows conceiving or farrowing for the period. Personnel below a 75% breeding efficiency rating are re-trained and re-evaluated at the end of the next period. Should a poor AI breeding performance be repeated, the employee would lose certification required to breed sows and be reassigned to another area of the farm.
Try and provide a central location for AI to standardize the breeding process. At Carroll's Foods, weaned sows or estrus gilts are brought to a 4 x 8 ft. breeding pen. Two pens are side by side to provide fence-line boar contact.
"This standardizes the breeding process and makes boar exposure during breeding consistent," says Hammer. To streamline the breeding process, all necessary equipment and supplies are in one location within reach of breeding personnel.
Post-Breeding Movement Hammer takes a strong stand on post-breeding movement. Don't move sows 5-35 days post-breeding, he says. Put bred sows in a place where they don't have to be moved until after 35 days post-breeding.
"I have seen it time and time again. We've bred too many females. We get pushed on space and we violate this moving rule. We end up with sows falling out and a low farrowing rate," says Hammer.