The Use of Vagina–Cervix Length Measurement in Evaluation of Future Reproductive Performance of Sows: A Preliminary Study under Commercial Conditions

SIMPLE SUMMARY: Animal production is focused on maximizing profits with simultaneous animal welfare protection. Thus, discovery of a simple, stress-free method for gilt selection would be an indispensable element for production improvement and would give necessary knowledge for producers. Our data showed that vagina–cervix length measurements could be a good, additional tool to predict a sow’s likely future reproduction efficiency. The advantages for this method are simplicity, speed, and no cost; the measurement is made as an element of the standard insemination procedure without additional stress and in a relatively early stage of life. Consequently, immediately obtained information gives high reliability and effectiveness in gilt selection. ABSTRACT: The length of the distal part of the internal reproductive tract seems to be related to the length and capacity of uterine horns, which is the most important anatomical property influencing litter size in sows. The aim of this study was to evaluate variation in vagina–cervix length (VCL) in gilts and differences in reproductive performance of sows according to VCL. The study was performed in a commercial farm using 221 gilts introduced into the breeding herd. Females were divided into three groups: (S) short (26.0 ± 2.0 cm, n = 36), (M) medium (31.3 ± 1.46 cm; n = 121), and (L) long VCL (36.0 ± 1.4 cm; n = 42) (p < 0.01). Mean live weight of gilts did not differ significantly among groups. Mean first litter size significantly varied between groups S (10.47 ± 3.01) and L (11.98 ± 2.32) (p = 0.0075) and M (10.67 ± 2.98) and L (p = 0.0054), while there was no significant difference between group S and M. Significant advantage (p = 0.023) was noted in the number of litters obtained from sows in groups L (4.69 ± 3.14), M (3.67 ± 2.71), and S (3.36 ± 2.40), and thus in total life production of sows (p = 0.0054), i.e., the number of piglets born alive. To conclude, the differences in vagina–cervix length in gilts during the first service was associated with significant variability in litter size during the first reproductive cycle, giving an advantage to females with longer VCL. Gilts with longer VCL were culled later and gave significantly more litters. Consequently, their lifetime piglet production was greater than gilts with shorter VCL.