Test day variability in yield and composition of Surti and Mehsani buffaloes milk at day 15 and 60 postpartum

Aim:

To estimate individual test day variability in yield and composition of Surti and Mehsani buffaloes milk at day 15 and 60 postpartum (pp).

Materials and Methods:

A total of 13 normally calved Surti and Mehsani buffaloes each maintained at Livestock Research Stations of Navsari and Sardarkrushinagar Dantiwada Agricultural Universities, respectively, were selected for the study. Milk sample was collected from each selected buffalo at day 15 and 60 pp to study milk yield and composition variability between these two breeds. Buffaloes were categorized for the ease of data analysis and comparisons into four groups, viz., S15 (Surti buffaloes 15^th day pp), S60 (Surti buffaloes 60^th day pp), M15 (Mehsani buffaloes 15^th day pp), and M60 (Mehsani buffaloes 60^th day pp).

Results:

There were 37.20% and 25.03% significant (p≤0.05) increase in mean test day milk yield (TDMY) of S60 and M60 as compared to S15 and M15 groups, respectively. The mean TDMY of Mehsani buffalo was 99.19% and 81.53% significantly (p≤0.05) higher than Surti buffaloes at day 15 and 60 pp, respectively. The mean fat and protein corrected test day milk yield (FPCTDMY) of all the groups was found to be significantly different (p≤0.05) from each other. There was significant (p≤0.05) increase of 1.94 and 3.45 kg in mean FPCTDMY with the progression of lactation between day 15 and 60 pp in Surti and Mehsani buffaloes, respectively. Similarly, the mean FPCTDMY of Mehsani buffaloes were approximately double with 103.27% and 96.36% higher yield as compared to Surti buffaloes at day 15 and 60 pp, respectively. Among milk composition, significant differences were observed for solid not fat (SNF) and protein%, whereas fat and lactose% were steady among four groups. The only significant (p≤0.05) difference was observed for SNF in M60 group, which was 8.29%, 6.85%, and 10.70% higher as compared to S15, S60, and M15 groups, respectively. The mean protein% in milk of Mehsani buffaloes was 21.01% and 33.05% significantly (p≤0.05) higher than Surti buffaloes milk at day 15 and 60 pp, respectively. However, there was a significant difference in protein% observed with the advancement of lactation in Mehsani buffaloes, but it was not so in the case of Surti buffaloes.

Conclusion:

Major consistent finding of the present study reveals that milk yield and protein% of Mehsani buffalo was significantly higher than Surti buffalo at day 15 and 60 pp.

Relative efficacy of conventional sperm parameters and sperm penetration bioassay to assess bull fertility in vitro

Frozen semen samples from 10 bulls were thawed and actively motile sperm recovered using a swim-up technique. Calcium ionophore A23187 at 0.5 microM concentration was used for 1 min to induce the acrosome reaction in the sperm. Mature female golden hamsters were superovulated with 50 IU of equine chorionic gonadotrophin followed 56 h later with 75 IU of human chorionic gonadotrophin. The cumulus mass was recovered 17 h after hCG treatment by puncturing the oviducts in the infundibulum region. Subsequently, cumulus cell mass and zona pellucida were digested by 0.1% hyaluronidase and 0.1% trypsin, respectively, to yield zona-free hamster eggs (ZFE). A sperm penetration bioassay was performed by coincubating capacitated sperm at 5 X 10(6) concentration and ZFE for 3 h at 38 degrees C in an air incubator. The conception rate of the bulls was based of an average of 82.6 cows per bull with pregnancy status confirmed by rectal palpation. It was found to be strongly correlated (p < 0.01, r = 0.723) with fertilization percentage, whereas percent motile sperm, percent viable sperm and percent sperm with intact acrosomes were not significantly correlated with the conception rate (r = 0.210, -0.021 and -0.468, respectively). Results of the present study suggest that the sperm penetration bioassay can be reliably used to test the fertilizing potential of bull sperm in vitro.

Evaluation of fertility status of Murrah buffalo bulls in vitro using zona-free hamster eggs

Cryopreserved semen samples from 10 Murrah buffalo bulls were used for sperm penetration bioassay using zona-free hamster oocytes. The samples were evaluated for sperm motility, viability and acrosome integrity. Actively motile spermatozoa recovered by the swim-up technique were capacitated using calcium ionophore A(2 3 1 8 7). Mature female golden hamsters were superovulated with 50 IU PMSG followed 56 h later by 75 IU hCG. Cumulus mass, recovered by puncture of oviducts at the infundibulum region, was treated with 0.1% hyaluronidase and 0.1% trypsin to obtain zona-free oocytes. After coincubation of zona-free oocytes with capacitated buffalo spermatozoa, scoring was done as fertilization percentage and fertilization index. The correlation coefficients with conception rate were statistically significant with fertilization percentage (r = 0.588, P < 0.05) and fertilization index (r = 0.660, P < 0.01). However, conventional parameters like viability, motility and acrosome integrity showed poor correlation with conception rate.