Table 1 Least squares mean differences in serum levels of oestrone sulphate between litter size classes A, B and C in sows and gilts 24 days after first AI or mating. (Litter size class A included 3–9 piglets; class B included 10–14 piglets and class C included 15–22 piglets; all numbers representing total number of piglets born.) The model included the fixed effect of parity 1–5 (p < 0.10).

From: Oestrone Sulphate Measurements for the Prediction of Small or Large Litters in Pigs