In the first part of this series, we discussed why sow parity and litter size must be considered critical indicators in sow management, as they have a considerable impact on litter performance. Now, we bring a new element to this conversation: gilt and sow nutrition. As some studies have demonstrated, to optimize sow performance, the type and amount of nutrients must differ in a young sow compared to older females (Boyd et al., 2008). In addition, using different approaches to feeding sows based on their parity also has some economic benefits. With that perspective, this article highlights how feeding younger and older sows differently can improve progeny performance.

One of the first things to consider when comparing feeding strategies for sows based on their parity order is that higher parity sows are generally provided with less feed relative to their body weight. Taking this into consideration, monitoring and adjusting feed composition can be a good strategy to compensate for relative low feed intake and the different nutrient requirements needed to help older sows continue to perform well. There is substantial evidence that amino acid requirements differ significantly among sow age groups, especially during lactation. As Kim et al. (2009) highlighted, maternal tissues mobilize different amino acid profiles from dietary protein, and the optimum amino acid profile depends on the sow’s parity. Threonine is a limiting amino acid for primiparous sows with low lactation feed intake, as a significant amount of threonine is mobilized from body tissue during lactation. On the other hand, valine is a limiting amino acid in multiparous sows that have a high feed intake and less tissue mobilization.

The energy requirement is another crucial element to consider, as energy intake must be limited during gestation to maintain ideal body condition (Jang et al., 2014). Fang et al. (2019) highlight that dietary energy requirement of a multiparous sow is higher when compared with a primiparous sow. For example, in a recent study, Jin et al. (2018) evaluated a group of 52 sows over three consecutive parities. Results showed that an adequate energy intake should be between 6,400 and 6,600 kcal of ME/d for gestating parity one sows; whereas, 7,040 and 7,260 kcal of ME/d for parity two sows and 7,680 and 7,920 kcal of ME/d for parity three sows. 

Although older sows are often limit-fed based on energy and body condition, other elements must be considered. For instance, if the higher parity sows are limit-fed to manage body condition, their consumption of micronutrients (such as vitamins and trace minerals, VTM) will also be lower. That’s why specific rations with micronutrient concentrations that are adjusted accordingly for younger and older parity sows may be beneficial. Using data from PIC, specialists from dsm-firmenich have identified that the vitamin and mineral consumption per unit of body weight will decrease with each advancing parity if their concentrations are not adjusted. Compared to sows in their first parity, it’s estimated that third and fifth parity sows consume about 27% and 43% fewer vitamins and minerals per unit of body weight, respectively (data published on Pig Progress, 2015). 

Adjusting the sow feeds based on the optimum vitamin and trace mineral (VTM) requirements for sows of different age/parity can significantly affect the production outcomes. Isabel et al. (2012) and Santos et al. (2020) proposed that as vitamins play a critical role in reproductive performance, providing sows with levels greater than the existing recommendations can have positive effects on sows and their litters. In their study, Santos et al. (2020) compared gestating and lactating sows supplemented with standard, industry levels of vitamins and sows fed with elevated levels of vitamins (a concept like the Optimum Vitamin Nutrition levels proposed by dsm-firmenich Animal Nutrition & Health). Results from that study showed that piglets from sows that received higher levels of vitamins weighed more at weaning when compared with the control group (5.43 vs. 5.23 kg, respectively). However, the higher levels of vitamins had no impact on sow body condition. 

Boyd et al. (2008) conducted a 12-month study involving four, “mature” sow groups (sows that have had 4 or more litters) of 2,650 animals each. Two groups were assigned to a control treatment that received the conventional diet with 0.15% VTM. Sows from the other two groups were provided with added VTM (choline and chromium) using a correction factor: 0.76 for pregnancy and 0.82 for lactation. The correction factor was intended to ensure a similar VTM intake for “mature” sows, relative to what they would have received as younger sows offered the conventional 0.15% VTM, on a g/kg body weight basis. This study showed that organizing sows into age groups and feeding mature, older sows an adjusted concentration of VTM can result in an increased number of pigs weaned per litter (or +1.44 pigs per sow/year). Additionally, research conducted at the IRTA Monogastric Nutrition Unit in Spain highlighted the importance of providing optimum vitamin levels, especially to higher parity sows. Results from that trial showed that sows receiving increased supplementation of vitamins lost only 2 pounds during lactation (control group, 13.6 pounds); experienced a 5.3-day wean-to-estrus interval (control group, 8.5 days); and weaned heavier pigs (17.2 vs. 16.7 pounds) with a greater number of pigs weaned per litter (10.9 vs. 10.2). 

Finally, swine producers should also consider the economic and management side of feeding sows strategically based on their age. Underfeeding or overfeeding sows (especially in terms of pounds of feed or the number of calories) has a massive impact on the reproductive, growth, and economic performance of the sows and their litters. The same can be true when feeding is not adjusted to meet the needs more precisely for sows of a particular age/parity group. Boyd et al. (2008), for example, divided a sow farm into two subpopulations, based on young (0-2) and older (3-10) parity sows, and an improved litter size was observed in both groups. 

This article has shown that sow nutrition should be considered a critical element in optimizing the relationships between sow parity and litter performance. With that in mind, high-quality vitamins and minerals are essential for sustaining the performance of older sows and their progeny. When VTM concentrations are provided at levels above current industry practices for older sows, the performance of older parity sows and their piglets can be improved.