I just returned from a trip to the Far East, where they are having awful problems with low litter size. They've purchased genetically improved females with a potential for 12-14 pigs, yet struggle to get eight. Of course, heat and appetite are their primary stumbling blocks, but after a subsequent tour here in the U.S., I found several farms struggling to breast 10. And in winter, too.
Because the management factors influencing litter size are so many (about 50) and are diverse and interlinked, I carry a checklist on to the farm. Basically, it boils down to five primary areas which you must check out if you are to get things better quickly.
Checking The Records What is the extent of the problem? The records can reveal poor management, stockmanship, maybe even disease, as well as spotlighting individual weaknesses all of which need to be confirmed (or not) by your eyes when the premises are toured.
Let the dog see the rabbit. Allow the adviser or vet uninterrupted time to read the records, before you, in your enthusiasm or anxiety, whisk him off to see the pigs.
What Affects Ovulation Here are the main errors: poor or no gilt flushing; too short acclimation; growing gilts too fast between entry and service; and mating too soon. Modern gilts look mature but often they have an immature sexual make-up. You've got to allow her hormones to catch up with her physical attributes.
Adequate lighting - as bright as your strip-lit kitchen for 16-18 hours/day - is important. Adequate variation of "parade" boars. Does the gilt "feel good?"
Check Fertilization Here are the main errors. Stress, not stimulation. Weaning too soon without following precautions; with your 16-18 day weaning you must be alert to what they are.
Among those precautions: have very "female" females; never let them nose-dive in lactation; check that the lighting pattern is correct; stimulate, don't stress, a sow after weaning; special lactation diet for first litter sow; don't be too keen to drop the daily intake too far between weaning and service; feed all lactating sows wet; recognize that the estrus will be one and a half days later, weaker and one day shorter.
Don't over use favorite boars. No AI back-up. Poor AI technique. Dirty, uncleaned rear ends; failure to sanitize boar's sheath. And, so often found, poor timing among the less experienced breeding herd managers, often because of too much to do.
Breeding is about spending time with the animals, not chasing your tail on repairs.
Poor Implantation The vital area is rest and quiet. Gosh, you Americans are so adrift on this one. You have those great gestation barns but right in the middle, among all the noise of feeding and movement, is your breeding section. Where, among other things, the pheromones are blown to kingdom come by your (excellent) ventilation. And, that's where your recently served sows remain.
Look - her hormone system has been subjected to the switchback stress of farrowing after a restful gestation, the excitement of suckling (and the bodily demands thereof), the mental trauma of the disappeared litter, the hormonal switchback into rebreeding mode then the excitement of sex.
Goodness gracious, all the old girl wants after all this is peace and quiet! Then she'll implant strongly, evenly and well. Stress her and she'll rebel reproductively and I don't blame her.
I'm sure the breeding section needs to be away from the gestation area. We are finding with our enforced group housing of sows here in England - with all its drawbacks - that it does encourage us to put those newly bred sows into a "rest house" area away from the brothel atmosphere to recuperate for a while.
Think about it, American building designers. You can go too far in cutting costs and labor-convenience; and you have, in my mind. You need to design part of your buildings for the 20-28days of implantation, so discuss this with your excellent pig vets. A good, sound-proofed division with separate ventilation will do, I guess.
Less Losses, Vigorous Pigs Attend farrowings; using prostaglandins properly and as an adjunct, oxytocin, this latter with veterinary guidance/training. Adequate food through pregnancy with an eye (and finger) on condition. So condition score as routine. It costs nothing. A gradual, gentle diet increase is better, I find, than a sudden boost of food energy pre-farrowing.
Keep things cleaner around farrowing. Water lactating sows in generous 2-gal. bowls, not those silly little bite-drinkers often set at an impossible angle. The sow hurts after parturition so she doesn't want the discomfort of too much getting up and down. She needs to suck in water like an elephant after eating, then subside gratefully.
Listen to them sigh in satisfaction when you "bowl" them. Effect is to drink more, eat more, milk more, rear more. There is a wonderful minimum-spill, self-filling/regulating trough on the European market. Gosh, what a difference! Very popular here in Europe.