A multivariate model for the prediction of pregnancy following laparoscopic artificial insemination of sheep

The effect of freezing and thawing techniques on the in vitro quality of pellet-frozen ram semen

The post-thaw quality of pellet-frozen ram semen was evaluated based on (i) sperm concentration, (ii) thawing diluent, and (iii) the number of pellets thawed simultaneously. Ejaculates from three Merino rams were collected, with four replicates per ram (n = 12 ejaculates) for each experiment. In Experiment 1, ejaculates were frozen at 200, 400, 600 or 800 × 106 sperm/ mL. In Experiment 2, ejaculates were frozen at 600 × 106 sperm/ mL and thawed in a dry test tube (control) or with 1 + 3 tris-citrate-fructose, tris-citrate-fructose+egg yolk, PBS+dye, PBS alone or IVF media (Emcare). In Experiment 3, groups of 1, 2 or 3 pellets were thawed in tris-citrate-fructose or a dry test tube (control). Post-thaw samples were tested for motility, acrosome and membrane integrity (FITC-PNA/PI) at 0, 3, and 6 h (all Experiments) and morphology at 0 h (Experiment 1). At 3 and 6 h post-thaw, motility was reduced at 200 × 10⁶ sperm/mL compared to other concentrations (P < 0.05). Across all time points, samples frozen at 800 × 10⁶ sperm/mL (P < 0.05) showed lower viability, while freezing at 200 × 10⁶ sperm/mL increased morphological abnormalities (P < 0.05). Thawing pellets with tris-citrate-fructose media resulted in higher motility, acrosome and membrane integrity 0, 3 and 6 h post-thaw (P > 0.05). Thawing one-pellet in tris-citrate-fructose improved motility and viability post-thaw (P < 0.05) compared to multiple pellets, while the number of pellets thawed had no significant effect when dry-thawed (P > 0.05). The results suggest that the optimal post-thaw quality is achieved when semen is frozen between 400 and 600 × 106 sperm/mL and thawed in tris-citrate-fructose media, one pellet at a time.

Genome-Wide Association Analysis of Boar Semen Traits Based on Computer-Assisted Semen Analysis and Flow Cytometry

Semen quality and persistence are critical for evaluating the usability of individual boars in AI, a standard practice in pig breeding. We conducted GWASs on various semen traits of Duroc boars, including MOT, DEN, ABN, MMP, AIR, and ROS levels. These traits were assessed using FCM and CASA. A total of 1183 Duroc boars were genotyped using the GeneSeek GGP Porcine 50 K SNP BeadChip. The GWAS was performed using three different models: GLM, MLM, and FarmCPU. Additionally, trait heritability was estimated using single- and multiple-trait PBLUP models, yielding 0.19, 0.29, 0.13, 0.18, 0.11, and 0.14 heritability for MOT, DEN, ABN, MMP, AIR, and ROS, respectively. All semen traits exhibited low heritability except ABN, which demonstrated medium heritability. Nine candidate genes (GPX5, AWN, PSP-II, CCDC62, TMEM65, SLC8B1, TRPV4, UBE3B, and SIRT5) were potentially associated with semen traits. These genes are associated with antioxidant and mitochondrial functions in porcine sperm. Our findings provide insight into the genetic architecture of semen traits in Duroc boars, and the identified SNPs and candidate genes may enhance economic outcomes in the pig breeding industry while improving sperm quality through targeted breeding strategies.