Milk fats are vital to neonate survival and development, but vary highly by diet, maternal metabolic state and stage of lactation. To gain a better understanding of changes in lipid composition of sow milk across lactation, milk was collected from nine multiparous sows on days 0, 3, 7, and 14, relative to birth and lipids were profiled using multiple reaction monitoring (MRM) profiling. Percent fat was determined by creamatocrit, and found to be different (P < 0.05) between day 0 (12.36 ± 5.90%) and day 3 (16.22 ± 3.65%) but not between day 7 (13.13 ± 2.19%) and day 14 (12.13 ± 2.45%). Fat was extracted from milk (n = 6/day) using the Bligh-Dyer method and profiled using tandem mass spectrometry MRM to determine the abundance of lipids defined by class and fatty acyl residue composition. Lipid species relative concentration was calculated from internal standards, and data analysis was performed using Metaboanalyst 4.0. Concentration of phosphatidyl-choline, -serine, -ethanolamine, -inositol, cholesteryl ester and sphingomyelin did not vary across lactation days, nor did the distribution of associated fatty acyl residues. The total abundance of triacylglycerides (TGs) and phosphatidylglycerols (PGs) increased (P < 0.05) from colostrum (day 0) to transitional (days 3 and 7) and mature milk (day 14). As lactation days increased from day 0 to day 14, the number of carbons and unsaturation within fatty acyl residues decreased (P < 0.05) in both TGs and PGs. The proportion of TGs and PGs increased (P < 0.05) relative to other lipid classes. Changes in composition of milk triglycerides and phosphatidylglycerols likely reflect the metabolic activity of the mammary gland and developmental needs of neonates.

Heat stress due to increasing extremes in ambient temperature and humidity results in reduced semen quality in boars. This has caused reduced efficiency of the swine industry, requiring more boars to breed the same number of sows. Vitamins such as vitamin C (VC) and E (VE) have been shown to improve semen quality in boars. Recently, vitamin D has been shown to improve semen quality in boars. The purpose of this experiment was to evaluate the effects of increased supplemental vitamins on boar reproduction during the summer season in a commercial boar stud. One hundred and sixty Pig Improvement Company (PIC) terminal line boars (n = 32 per treatment) and 39 maternal, heat-sensitive boars (n = 7 or 8 per treatment) were randomly allocated to treatment and fed a corn and soybean meal-based diet adjusted based on individual boar body condition score. A control (CNT) diet was used that met PIC recommendations for boars. Increased supplementation of specific vitamins was given in the form of a top-dress and consisted of CNT wheat middlings, CNT plus VC (560 mg/day), CNT plus 25-hydroxy vitamin D3 (VD) (125 µg/day), CNT plus VE (275 mg/day) and CNT plus VC, VD and VE (CDE). The experiment was split into three periods based on maximum daily high temperatures in the barn, where period 1 was weeks 1 to 4, period 2 was weeks 5 to 11 and period 3 was weeks 12 to 14. Semen was collected from boars as needed using the stud's normal production schedule and was analyzed for sperm quantity and quality characteristics. There were no dietary effects on semen volume, sperm concentration or total sperm production (P ≥ 0.553). Total motility of sperm was not impacted by diet (P = 0.115); although, VC tended (P = 0.064) to have a greater progressive motility than CDE. Percentages of morphologically normal sperm and normal acrosomes were not affected by dietary supplementation (P ≥ 0.157). Period effects were observed for most semen quality parameters, with quality generally becoming reduced over time. The present study demonstrates that increased supplementation of vitamins beyond PIC recommendations was not beneficial for boar reproduction during the summer.