Brief Summary of Minutes of Annual Meeting

The progress of previous projects, copper supplementation (led by Merlin), Essential oil (led by Merline), Boron (led by Merlin), and Phase feeding (led by Crystal) were discussed. The preliminary results of a boron study conducted by the UK suggested there is little or no effect of additional boron on reproductive performance. Thus, the committee voted to discontinue this project.  

The plan for new projects entitled Phytogentic feed additives (led by Merlin), Optimum Histidine (led by Robert), and Iron level (led by Crystal) on sow reproductive performance was visited. Teams also brainstormed on new research projects to sustain the sow longevity with the potential benefit of sodium salicylate supplementation, the good quality of drinking water, and the level of water intake. Also, the hemoglobin level fluctuated during gestation, and lactation, and the restored rate varied between parity was observed by SDSU, which warrants further research.

Short-term Outcomes: short term outcomes are reported within each research objective.

In the United States, sow mortality is a major concern in swine production. New genetic lines are selected to increase the number of pigs per year, but the culling rate remained around 50 to 60% after the primiparous cycle. The leading causes of euthanized are lameness and prolapses, while the top causes of death loss remained unknown. In addition, nonintentional culls are found in reproductive inefficiency females. As such, short term outcomes are related to investigation of nutritional tools to enhance sow productivity.

1. Sow blood hemoglobin (Hb) as an indicator of iron status was reported to decline with progressing pregnancy and into lactation with some recovery within the first 30 d of the subsequent pregnancy but the ability to recover declined with each pregnancy. This phenomenon was tested through 3 successive pregnancies in a single cohort. This decline in Hb has potential implications for offspring iron status at birth and sow Hb status may be a marker of piglet iron status to identify litters requiring additional iron supplementation.
2. Supplement Histidine: No specific outcomes related to this objective were reported. Activities completed and/or planned for this objective are reported under “Activities”.
3. Sow metabolic status:
   1. Sodium salicylate SDSU: Gilts fed sodium salicylate 3 days before farrowing, displayed reduced savage behavior in gilts. Sodium salicylate is an agonist of PGF2alpha and has an anti-inflammation effect, which might help soothe the gilts during the challenge stage.
   2. Water quality and intake level: Water is a major nutrient, but the level of water consumption and mineral intake from water on reproductive performance is sacrifice, and the challenge of finding the reference makes it difficult to propose a guideline for swine producers. Moreover, sodium salt is commonly used for its electrolyte balance, pH, and nutrient absorption functions and was reported to promote diet and water intake. Unlike the young pigs, which had been reevaluated recently, the study on salt levels in reproductive sows is missing and may be included as future efforts under this objective. Data from young pigs reveals the change in sodium and chloride requirements in new genetic pigs (Shawk et al., 2018; Shawk et al., 2019; Mahan et al., 1996; Mahan et al., 1999). Therefore, it is important to revisit its effect and optimal level in the modern genetic line of the sow. Seynaeve et al. (1996) found that increased sodium chloride to 0.4% increased urine output, shorter the wean to estrus interval, and increased rebreeding rate and NRC 2012 recommended 0.15% and 0.20% of sodium while 0.12% and 0.16% of chlorine for gestation and lactation sow, respectively.
4. Sensory additives: No outcomes on this objective during this reporting period.

Outputs: outputs reported are from the previous approved project objectives related to 1) copper supplementation, 2) boron, 3) phytogenics, and 4) phase feeding.

Performance data from the Copper supplementation project were collected, and the manuscript is being prepared. Milk samples collected from the copper project have been assayed, and results will be compiled into another paper. Results from the essential oil, Boron, and phase feeding projects were summarized and are proceeding for manuscript preparation.

Activities: activities reported are specific to current project objectives on 1) iron, 2) histidine, 3) sow metabolic status, and 4) sensory additives

The team will discuss the procedures and traits to be measured in each of the projects proposed above. In addition, the project will evolve to investigate responses at the molecular level as a means to identify the biomarkers associated with reproductive performance, and our committee is looking forward to seeking federal funding to support the project. To approach this goal, the team will search for collaboration with molecular geneticists and reproductive physiologists.

The protocol for His study will be shared with participating stations. Briefly, sows will be allotted to their treatments at d 110 of gestation. Colostrum will be collected at farrowing, and milk will be collected during the lactation. In addition to milk, the collection of other biomarkers was considered, including immunocrit and cortisol.

Milestones:

To lay out a research plan for the histidine project by 2024.

In the coming year, evaluate the research plan for sodium salicylate, water quality and intake, and monitor sow BW change projects.

A cooperative study assessing the effects of a second iron injection administered before weaning on growth performance, hematological status, and tissue mineral concentrations of nursery pigs. 2024. T.B. Chevalier, O. Adeola, S.D. Carter, C.R. Dove, M.J. Estienne, C.L. Levesque, C.V. Maxwell, T. Tsai, and M.D. Lindemann. Applied Animal Science 40:112-123. https://doi.org/10.15232/aas.2023-02480