Relationship Between Routine Analysis/Sperm Function and Fertility Tests of Cattle Bull Semen

Seminal attributes of Vechur bulls (Bos indicus), the smallest humped dairy cattle

The study was undertaken at Mattupatti semen station to objectively evaluate the seminal attributes of frozenthawed semen of Vechur bulls, the smallest humped dairy cattle in the world, using the computer assisted semen analyzer (CASA) and Flow cytometer. The mean motility and progressive motility of the frozen-thawed semenestimated via CASA was 77.25±9.56 and 64.0±4.21% respectively. Mean values obtained for the sperm kinetic parameters like path velocity (VAP), progressive velocity (VSL), track speed (VCL), lateral head amplitude (ALH),beat cross frequency (BCF), straightness (STR) and linearity (LIN) were 82.56±12.12, 76.22±10.38, 107.77±21.42, 4.39±0.91, 20.87±3.81, 92.37±3.25 and 72.87±6.64% respectively. Flow cytometry analysis of the functional sperm parameters like sperm viability, live sperms with intact acrosome, sperms with normal mitochondrial membranepotential (MMP) and sperms with altered DNA were 81.67±4.55, 76.16±9.76, 82.40±5.61 and 11.75±0.3% respectively. The mean value of the HOS reactive sperms was 71.81±5.71%. Mean values for the length and width of the sperm head, length of mid-piece, tail and overall sperm length measured by computer image analysis was 8.99±0.36, 5.07±0.23, 14.21±0.35, 45.12±1.53 and 68.32±1.41 μm respectively. Study concluded that seminal attributes of Vechur bulls could be estimated with CASA and Flow cytometer and the parameters were comparable to other indigenous, crossbreds and exotic dairy cattle.

Cellular and Functional Physiopathology of Bull Sperm With Altered Sperm Freezability

The objective of this study was to ascertain the cellular and functional parameters as well as ROS related changes in sperm from bulls with varied sperm freezability phenotypes. Using principal component analysis (PCA), the variables were reduced to two principal components, of which PC1 explained 48% of the variance, and PC2 explained 24% of the variance, and clustered animals into two distinct groups of good freezability (GF) and poor freezability (PF). In ROS associated pathophysiology, there were more dead superoxide anion positive (Dead SO+) sperm in GF bulls than those in PF (15.72 and 12.00%; P = 0.024), and that Dead SO+ and live hydrogen positive cells (live H₂O₂+) were positively correlated with freezability, respectively (R² = 0.55, P < 0.0130) and (r_s = 0.63, P = 0.0498). Related to sperm functional integrity, sperm from PF bulls had greater dead intact acrosome (DIAC) than those from GF bulls (26.29 and 16.10%; P = 0.028) whereas sperm from GF bulls tended to have greater live intact acrosome (LIAC) than those from PF bulls (64.47 and 50.05%; P = 0.084). Sperm with dead reacted acrosome (DRAC) in PF bulls were greater compared to those in GF (19.27 and 11.48%; P = 0.007). While DIAC (R² = 0.56, P = 0.0124) and DRAC (R² = 0.57, P < 0.0111) were negatively correlated with freezability phenotype, LIAC (R² = 0.36, P = 0.0628) was positively correlated. Protamine deficiency (PRM) was similar between sperm from GF and PF bulls (7.20 and 0.64%; P = 0.206) and (r_s = 0.70, P = 0.0251) was correlated with freezability. Sperm characteristics associated with cryotolerance are important for advancing both fundamental andrology and assisted reproductive technologies across mammals.

Assessment of semen quality in pure and crossbred Jersey bulls

AIM

To compare the seminal attributes of neat, pre-freeze (at equilibration), and post-freeze (24 h after freezing) semen in pure and crossbred Jersey bulls.

MATERIALS AND METHODS

Total 36 ejaculates (3 ejaculates from each bull) were collected from 6 pure Jersey and 6 crossbred Jersey bulls and evaluated for various seminal attributes during neat, pre-freeze, and post-freeze semen.

RESULTS

The mean (±standard error [SE]) values of neat semen characteristics in pure and crossbred Jersey bulls were recorded such as volume (ml), color, consistency, mass activity (scale: 0-5), and sperm concentration (millions/ml). The extended semen was further investigated at pre-freeze and post-freeze stages and the mean (±SE) values recorded at neat, pre-freeze, and post-freeze semen were compared between pure and crossbred Jersey bulls; sperm motility (80.55±1.70%, 62.77±1.35%, 46.11±1.43% vs. 80.00±1.80%, 65.00±1.66%, 47.22±1.08%), live sperm count (83.63±1.08%, 71.72±1.09%, 58.67±1.02% vs. 80.00±1.08%, 67.91±1.20%, 51.63±0.97%), total abnormal sperm count (8.38±0.32%, 12.30±0.39%, 16.75±0.42% vs. 9.00±0.45%, 12.19±0.48%, 18.11±0.64%), hypo-osmotic swelling (HOS) reacted spermatozoa (71.88±0.77%, 62.05±0.80%, 47.27±1.05% vs. 72.77±1.02%, 62.11±0.89%, 45.94±1.33%), acrosome integrity (89.05±0.83%, 81.33±0.71%, 71.94±0.86% vs. 86.55±0.57%, 78.66±0.42%, 69.38±0.53%), and DNA integrity (99.88±0.07%, 100, 99.66±0.11% vs. 99.94±0.05%, 100, 99.44±0.18%,). The volume, color, consistency, sperm concentration, and initial motility in pure and crossbred Jersey bulls did not differ significantly (p>0.05). The mass activity was significantly (p<0.05) higher in pure Jersey as compare to crossbred Jersey bulls. Live sperm percentage and acrosome integrity was significantly (p<0.01) higher in pure Jersey bulls as compared to crossbred Jersey bulls. However, no statistical difference (p>0.05) was observed in abnormal sperm; HOS reacted spermatozoa and DNA integrity percentage among breeds.

CONCLUSION

It may be concluded that the quality of pure Jersey bull semen was comparatively better than the crossbred Jersey bulls.