Amelioration of the periparturient relaxation of immunity to parasites through a reduction in mammalian reproductive effort

► We assessed the rate at which overcoming nutrient scarcity reduces parasitism. ► Reducing litter size in lactating rats ceased weight loss and reduced egg counts. ► Reducing litter size increased mucosal mast cell and eosinophil numbers. ► Circulating antibodies and cytokine profiles were not affected. ► In conclusion, restoring nutrient adequacy rapidly improves resistance to infection.