Every year sow productivity improves. According to the USDA the average litter size has gone from 7.2 pigs in 1980 to 10.6 in 2017. This growth is due to two key factors: genetic advances and the evolution of better management practices.

Even as genetics and management drive better per-litter productivity, it’s still important to manage those sows so they stay in the herd as long as possible. From an economic standpoint, a sow needs to have three litters in order to cover the investment it took to raise her. So any litter farrowed after that point adds to the profitability of the animal, making it more important for sows to stay in the herd longer.

Yet even as these sows are producing at a high level, the risk of an incident that sends them off course and off the farm is high. Like a high-performance car travelling at high speed, any rock in the road can throw it off course.

So the question is, how can producers maximize productivity and longevity at the same time? The answer starts all the way back when the sow was a fetus.

A study conducted by Dr. Billy Flowers at North Carolina State University looked at sows with good herd longevity, measured as having six or more litters. Looking at management of those sows, the data suggests that half to 60% of the lifetime productivity of those sows was related to weights at three key points: birth, weaning and puberty.

As Dr. Flowers puts it, when gilts are young they’re “building their engine”, meaning the ovaries and uterus. Gilts that build a better and more efficient reproductive engine will perform better as adults, Dr. Flowers says.

Bigger gilts at those three key weight phases—birth, weaning, pre-breeding/puberty—are highly correlated to better ovary and uterine development. While the ideal weights are different for every farm, small pigs or those that don’t grow well are usually not going to be productive sows.

Dr. Flowers lists three key opportunities to know if pigs will be productive sows:

1. Colostrum intake. While genetics is important, management of those just-born pigs is just as important and that all starts with high quality colostrum. Not only does colostrum deliver passive immunity piglets need to fight diseases, colostrum is also critically important to the development of reproductive organs. Studies show that if colostrum intake in piglets is low, those pigs are more likely to be culled before being bred the first time. That’s true for replacement gilts or animals destined for market.
2. What’s her weight? Know the average birth, weaning and puberty weights for your herd and understand where each individual falls in relation to those weights. Data would suggest that larger birth weight animals are the ones to keep as replacement females since they are more likely to breed earlier and stay in production longer.
3. Know the litter of origin. There are plenty of incidents where high-genetic females in multiplier herds fail to produce replacement females that meet the criteria to stay in the herd. Some sows are better at transmitting genetics and producing replacement females, so understand which sows in your herd are the best genetic transmitters.

The goal for most sow operations is to have sows that last to at least six litters. If producers do a good job up front when pigs are born, they are less likely to have issues with sows later in life. Those sows that stay past their sixth litter are ones that excelled in their growth phase early in life.

To hear more from Dr. Flowers related to gilt health and management, be sure to listen to this episode of Food Chain Chats.