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ThesisItem Open Access INFLUENCE OF THERMAL STRESS ON POST-PARTUM REPRODUCTIVE PERFORMANCE OF CROSSBRED DAIRY COWS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD, 2020-05-12) C. IBRAHEEM KUTTY; Azees C P, AbdulTogether with increasing productivity of dairy cows, vulnerability to thermal stress (TS) and fertility impairments have become serious concern in the context of ongoing climate change phenomenon. The study was carried out at LRS Thiruvazhamkunnu in Kerala, to elucidate TS influence on reproductive performance of crossbred dairy cows and to identify suitable biological markers for timely intervention. The study involved retrospective assessment of reproductive performance in comparison with climatic variables over a period of six years and prospective investigation of the climatic stress impact on various production and reproduction parameters round the year. Major climatic stress factors showed significant (P<0.001) variation between seasons with highest ambient temperature during summer and lowest in rainy season. Relative humidity was rather high throughout the years so that THI was high enough to cause mild to moderate TS across all the seasons. Corresponding to the extended influence of TS factors, reproductive performance was much below the expected level irrespective of the seasons. Prospective study also showed almost similar pattern of stress impact throughout the year. The biological response assessed based on HSP 70 and Cortisol levels in the serum indicated the prevalence of TS during all seasons with maximum during summer. Respiration rate, rectal temperature and serum MDA level also showed highly significant elevation during summer being the immediate response to stress. However, production and reproduction related parameters showed more or less uniform levels of overall performance between seasons. It is concluded that overall lowered herd fertility is the consequence of TS exposure throughout the year. In spite of more adverse climate during summer, uniform fertility across seasons appears to be due to the adaptation mechanism, reflected by the high level of HSP 70 in the serum. Hence HSP 70 can be used as an effective indicator of TS in crossbred dairy cows.ThesisItem Open Access REPRODUCTIVE PERFORMANCE OF COWS UNDER HOMOEOTHERMAL DISTURBANCES(COLLEGE OF VETERINARY AND ANIMAL SCIENCE,MANNUTHY, 1995) ATHMAN, K V; Sudarsanan, VBased on the data on the maximum, minimum temperature and humidity for a period of two years, a year of study was divided into four seasons of JJA, SON, DJF and MAM. The mean maximum environmental temperature of the seasons were 29.56, 31.52, 32.73 and 34.88°C respectively. Two thousand two hundred and ninety eight cows brought to the AX centre from the homesteads of Mannuthy were grouped into 11 treatments of pre and post insemination rests and no rests. They were bred by artificial insemination and results of insemination were assessed on the basis of non-return. Mean conception rate of the seasons were statistically analysed to know the effect of environmental temperature and the effect of pre and post insemination rests to the animals. There was no significant difference in conceptions between seasons, between the post insemination rests and no rests and between pre insemination rests of 30 and 60 minutes and no rest. Conception per cent was icantly higher in the animals those were given pre insemination rest for 90 and 120 minutes. Animals with light coat colour had a significantly higher conception rate than those with dark colour irrespective of the seasons. Animals inseminated in the afternoon were generally found to have a better conception rate than those inseminated in the forenoon. There was no significant difference in the conception rate of heifers and cows both between seasons and between themselves. So also, there was no significant difference in conception rate of parity groups both between seasons and between themselves. Statistical analysis of seasonal mean weight of foetal membranes, mean number of cotyledons and mean area of cotyledons and mean birth weight of calves did not show any correlation to suggest influence of seasonal environmental temperature on placental development and birth weight of calves.ThesisItem Open Access MORPHOLOGY AND VIABILITY OF BOVINE EMBRYOS FROZEN IN MEDIA CONTAINING BSA AND PROPANEDIOL(COLLEGE OF VETERINARY AND ANIMAL SCIENCES Mannuthy - Thrissur, 2000-10) RAMACHANDRAN, K.; . Suresan Nair, S.PThe observation of the study was to compare the effect of Bovine Serum Albumin (BSA) and 1,2 Propanediol on the morphology and viability of bovine embryos frozen under two freezing and thawing protocols, A total of sixteen crossbred cows, kept under identical conditions, maintained in the Network Project on Embryo Transfer attached to the Department of Animal Reproduction, College of Vetennary and Animal Sciences, Thrissur. The animals were superovulated by Folltropm-V and Prosolvm, starting on the day 11 of the cycle. Of the 16 cows superovxilated 13 showed good response. While two cows did not show any response, there were multiple follicles in both the ovanes without any evidence of ovulation in the third animal. A total of 85 (76 transferable and 9 non transferable) embryos were recovered from a total of 24 flushings from 13 cows, non-surgically on day 7. A total of 56 embryos (mean 3.50 ± 0.822) were recovered m the first treatment, from 13 flushings. In one cow, though, there was 80 per cent flushing, no embryos could be recovered. While 22 embryos (mean 2.75 ± 0.861) were recovered m the second treatment from 8 flushings, only 7 (mean 1.4 ± 0.4) embryos were recovered in the third treatment, from 5 flushings. A total of 72 transferable (60 morulae and 12 blastocysts) were sleeted for the freezing tnals. The embryos were divided into three groups with 24 (20 morulae and 4 blastocysts) embryos and assigned to three media. The first medium was FBS with !0 per cent glycerol, second PBS containing 10 per cent glycerol and 1 per cent BSA; the third medium was with a composition of 10% glycerol and 20% 1,2 propanediol in PBS. Two freezing protocols were used for freezing of the embryos. In the first protocol, with 12 embryos (10 morulae and 2 blastocysts), the initial cooling was at a rate of 1 °C/min from room temperature to -6°C and then at a rate of 0.3°C/min to -35°C, while in the second protocol the initial rate of cooling was at 5°C/mm to -7°C and then at 0.3°C/mm to -30°C before transferring to liquid nitrogen. Thawing was earned out at 37°C for 20 sec after 30 days of preservation. Cryoprotectants were removed by two methods, a four step-wise using decreasing concentrations of cryoprotectants m the first method and one step using 1M sucrose phosphate buffered saline in the second. Thirty four embryos (26 morulae and 8 blastocysts) found normal after freezing and thawing were subjected to culture for 24 h in PBS enriched with 4 per cent BSA at 37°C and 5 per cent CO2 tension. Sixteen embryos (13 morulae and 3 blastocysts) were transferred to 15 recipient cows. While one cow was confirmed pregnant on examination 60 days after transfer, eleven cows returned to heat subsequently, two cows came to oestrus on days 34 and 35 respectively, after the transfer. The third showed oestrum on 45*'' day of transfer. The glucose, acid phosphatase and alkaline phosphatase values showed a normal range of 86.2 to 195.2 mg/100 ml; 14.17 KA to 22.3 KA and 119.02 to 129.00 KA (mean 128.075 ± 9.019, 18.675 ± 0.667 and 122.67 ± 0.788) respectively in the lummal fluid of the recipient animals. The average serum progesterone levels on day 0, 14 and 28 days after oestrus in 11 cows which showed subsequent heat after the transfer were 0.357 ±2.140, 3.053 ± 0.420 and 2.572 ± 0.627 ng/ml and that of the animals which failed to show oestrum were 0.157 ± 0.166, 3.793 ± 0.406 and 3.867 ± 0.362 ng/ml respectively. While significant difference was seen between the freezing media I and II and II and III respectively on the morphology of embryo after the freezing and thawing, no significant differences were seen between the media I and III, between the freezing protocols and cryoprotectant removal procedures on the morphology of embryos frozen. No significant differences were noticed on the effect of the freezing media, freezing protocols and the cryoprotectant removal procedure after the culture on the morphology of the embryos.
