Effects of gestational anemia on farrowing duration and reproductive outcomes in highly prolific sows in a tropical climate.

Abstract

A total of 1136 multiparous sows from commercial swine farms in Thailand were included and categorized based on their blood hemoglobin (Hb) concentration measured at 109-113 days of gestation using a photometric method (Hb&#xa0;<&#xa0;10&#xa0;g/dL&#xa0;=&#xa0;anemic; Hb&#xa0;&#x2265;&#xa0;10&#xa0;g/dL&#xa0;=&#xa0;normal). Reproductive and metabolic parameters, including farrowing duration, time from last pig to placental expulsion, litter size born, colostrum quality (Brix percentage), circulating concentrations of glucose and cholesterol, prepartum progesterone levels, and backfat thickness, were recorded. Anemic sows (n&#xa0;=&#xa0;515) exhibited longer farrowing durations and placental expulsion times than normal sows (n&#xa0;=&#xa0;621) (p&#xa0;<&#xa0;0.001). Compared to normal sows, the number of piglets born alive was lower for anemic sows (p&#xa0;=&#xa0;0.03) although total born and stillbirth rates were not statistically different. Compared to normal sows, anemic sows had lower blood glucose (p&#xa0;=&#xa0;0.02) and cholesterol (p&#xa0;=&#xa0;0.005) concentrations and higher prepartum progesterone concentrations (p&#xa0;=&#xa0;0.03). Progesterone concentrations and farrowing durations increased with longer intervals between sampling and parturition, highlighting the importance of timing in hormonal assessment. Regression analysis identified progesterone levels, sampling interval, gestation length, and hemoglobin concentration as significant predictors of farrowing duration, explaining 58&#xa0;% of its variability. Anemia during late gestation was associated with prolonged farrowing, altered metabolic status, and impaired reproductive outcomes in sows. These findings highlight the need for targeted anemia prevention and management strategies to enhance farrowing efficiency and piglet survival in commercial swine operations.