MORPHOMETRIC CHARACTERISTICS OF FEMALE PIGLETS FROM DIFFERENT SEX RATIOS

Abstract

In a male-biased litter, there is a greater chance that a female is positioned in between two male siblings while in utero. This may lead to masculinized females with different phenotype, behavior and reproductive performance. To determine the effects of sex ratio on morphometric characteristics of female piglets, litters were classified as having ≥60% (H group) or <60% (L group) male siblings. Crown-rump length (CRL), body weight (BW), and anogenital distance (AGD1, AGD2, AGD3) of one hundred seventeen three-day-old female piglets from thirty-one litters were measured. Weight by length and adjusted anogenital distance were calculated, and the number of teats was recorded. H group had significantly lower CRL (P<0.05) and BW (P<0.05) compared to L group. AGD and teat number were not different between groups. Female AGD3 is correlated with BW (r=0.635, P<0.001), weight by length (r=0.581, P<0.001), and CRL (r=0.714, P<0.001) while AGD2 has similar positive relationships with weight by length (r=0.370, P<0.05) and CRL (r=0.508, P<0.001). Results suggest that BW and CRL are sensitive to the effects of sex ratio.