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The study had two objectives, namely, to estimate the andrological disorders leading to disposal of Karan Fries (KF), Sahiwal cattle and Murrah buffalo bulls and to study the effect of various factors (species/breeds, season of birth and period of birth) on male reproductive parameters. Records on occurrence of subfertility problems and disposal pattern of bulls maintained at the National Dairy Research Institute herd were collected for 15 years (1991 to 2005). Percentage of bulls producing freezable semen was less in the crossbred cattle (58.46%) as compared to Sahiwal (81.69%) and Murrah bulls (81.05%). Various subfertility traits like poor libido and unacceptable seminal profile were found to be the significant reasons (p<0.01) for culling of the breeding bulls. Inadequate sex drive was the main contributing factor for bull disposal in Sahiwal (22.55%) and Murrah bulls (15.12%) whereas poor semen quality and freezability were most frequently observed in KF bulls (24.29 and 7.29 percent, respectively). Least squares analyses of different male reproductive parameters showed that species/breeds had significant effect (p<0.05) on all traits except for frozen semen production periods (FSPP). Periods of birth were significantly different (p<0.05) for all traits except for semen volume. Age at first semen collection (AFSC), age at first semen freezing (AFSF) and age at disposal (AD) were highest in Murrah, while frozen semen production period (FSPP) and semen production period (SPP) were highest in KF and lowest in Sahiwal. The age at first semen donation and breeding period could be reduced by introducing the bulls to training at an early age. These results revealed a declining trend in AFSC, AFSF, FSPP, SPP and AD, thereby indicating an improvement in reproductive performance over the years. The age at first semen donation in bovines can be reduced by introducing the young male calves to training at an early age, which could increase the dosage of semen obtained from each male.

The objective of the study was to determine the effect of season, period, age, bull, and ejaculate on semen quality in Sahiwal bulls. Semen production records from 1996 to 2006 of 5,483 ejaculates from 46 Sahiwal bulls maintained at Artificial Breeding Complex, NDRI, Karnal, India were analyzed using least square analysis of variance by LSML software package. The overall least squares means of ejaculate volume (VOL), total volume per day (VOLD), mass activity (MA), initial motility (IM), sperm concentration per ml (SPC), and sperm concentration per ejaculate (SPCE) were 3.79 ± 0.02 ml, 5.81 ± 0.06 ml, 2.32 ± 0.01, 55.47 ± 0.001%, 766.69 ± 5.50 × 10(6)/ml and 3023.25 ± 30.15 × 10(6), respectively. All semen traits (VOL, VOLD, MA, IM and SPCE) were significantly (P < 0.01) affected by age groups, season and period, whereas season had significant effect on VOL at 5% level. During hot-humid season, highest value of VOL, VOLD, MA, IM, SPC, and SPCE were observed followed by summer and cold season. Highest value of VOL, VOLD, IM, and SPCE were observed during period-3 (2004-2006), whereas highest value of MA and SPC were observed during period-1 (1996-1999). However, lowest magnitude of MA, IM, SPC, and SPCE during period-2 (2000-2003) was observed. Ejaculate characteristics like VOL, VOLD, and SPCE increased with the increasing age of bull up to 5 years and then decreased. Significant (P < 0.01) bull to bull variation was found in VOL, VOLD, MA, IM, SPC, and SPCE traits. First ejaculate had significantly (P < 0.01) higher MA, IM, SPC, and SPCE. Hence, it could be concluded that during rainy season and period-1 and period-3 the quality of semen is quantitatively and qualitatively good. Better quality semen was obtained up to 5 years of age in Sahiwal bulls.

Egg yolk-Tris is most commonly used semen extender; however, its use involves hygienic risk, interference with fertility and poor microscopic examination. Therefore, replacement of egg yolk with a plant-based component with protective effects on spermatozoa would be advantageous. In present study, we observed effect of soya milk-based extenders on dilution and liquid preservation of Murrah buffalo bull semen at 5°C up to 72 h in comparison with conventional egg yolk-Tris extender (Ext.1). In experiment one, a total of 32 buffalo semen ejaculates from four animals were extended and preserved at 5°C for 72 h in soya milk-based extender (Ext.2) with different percentages (10%, 15%, 20%, 25% and 30%) of soya milk for optimization of soya milk concentration. Semen quality was assessed for individual motility, viability, membrane integrity and acrosome integrity at 0, 24, 48 and 72 h of liquid preservation. The results of experiment one indicated that 25% soya milk is an optimum concentration for buffalo bull semen extender preparation. A modified method was used to prepare another soya milk-based extender (Ext.3). In the second experiment, two soya extenders (Ext.2 and 3) with optimized concentration (25%) of soya milk were comparatively assessed with egg yolk-Tris extender (Ext.1) for semen quality parameters at 0, 24, 48 and 72 h of liquid preservation. The individual sperm motility at 0 and 24 h following dilution were found non-significant among extenders. However, after 48 h of dilution, individual motility in Ext.3 was observed significantly (p < 0.05) higher than Ext.1. After 24, 48 and 72 h of dilution sperm membrane integrity in Ext.3 was found significantly (p < 0.05) higher than Ext.1. Overall, comparative evaluation of sperm parameters obtained revealed that Ext.3 containing 25% soya milk can be used as a substitute of egg yolk-based extender for buffalo semen liquid preservation.