Cholesterol concentration
There was no significant difference in serum total cholesterol concentration between days of the treatment with DPG protocol. The values varied non-significantly in pregnant and non-pregnant buffaloes on day 28 post AI in both farm (99.23±2.1 vs 97.76±1.45) and field (92.44±3.46 vs 86.21±2.65) condition. Similarly, the values of total cholesterol concentration varied non-significantly in pregnant and non-pregnant buffaloes on day 28 post AI in farm during breeding season (101.29±2.7 vs 98.76±1.48) and low breeding season (98.22±1.9 vs 96.72±1.43), while the corresponding values in field during breeding season was 99.47±1.49 vs 88.23±1.67 and during low breeding season was 93.41±1.43 vs 84.20±1.61.
In the present study the mean cholesterol concentration (mg/dl) recorded in DPG group was in agreement with the findings of
Khasatiya et al., (2016). On the contrary, the findings of
Phani (2017) revealed a higher mean cholesterol (mg/dl) concentration in buffaloes during the low breeding season under farm conditions.
Prajapati et al., (2011) recorded a higher mean cholesterol (mg/dl) concentration in buffaloes treated with double PG protocol reared under farm conditions during early breeding (188.44±12.66), breeding (184.93±10.15) and low breeding (179.32±12.92) seasons.
There was no significant difference in serum total cholesterol concentration between days of the treatment with POVS protocol. The values varied non-significantly in pregnant and non-pregnant buffaloes on day 28 post AI in both farm (88.12±2.12 vs 86.12±2.13) and field (84.22±1.13 vs 79.12±2.13) condition. Similarly, the values of total cholesterol concentration varied non-significantly in pregnant and non-pregnant buffaloes on day 28 post AI in farm during breeding season (90.54±0.64 vs 92.12±0.87) and low breeding season (87.5±0.87 vs 88.12±2.91). However, the variations in the mean cholesterol concentration (mg/dl) might be due to the differences in season of study, nutritional and health status of the selected buffaloes.
Progesterone concentration (ng/ml)
The mean P4 levels on day -10, 0 and 11 were more than 1ng/ml. Thereafter the mean P4 levels dropped steeply on day of AI. These levels again increased significantly on day 21 post AI in pregnant buffaloes whereas decreased significantly in non-pregnant buffaloes both in farm and field. Significant difference was observed in P4 level between pregnant and non-pregnant buffaloes on day 21 both in farm and field. Similarly, P4 levels increased significantly on day 21 post AI in pregnant buffaloes, whereas decreased significantly in non-pregnant buffaloes both in farm and field during breeding and low breeding season.
In the present study, the mean progesterone level during different periods of treatments in DPG group was in agreement with the findings of
Phani (2017) who recorded the mean P4 levels (ng/ml) at day (-10), 0, 11 and on the day of AI was 1.34±0.15, 1.56±0.14, 1.67±0.52 and 0.66±0.05 ng/ml, respectively in buffaloes reared under farm conditions during the low breeding season, while
Pandey et al., (2011) recorded the mean P4 levels (ng/ml) on the day of AI and 21 days post AI as 0.33±0.10 and 2.1±0.20, respectively in pregnant buffaloes and 0.35±0.10 and 1.1±0.30, respectively in non-pregnant buffaloes reared under farm conditions.
The data show that the mean serum progesterone concentrations on day -10 (>1 ng/ml) were decreased to basal values on day 0 and increased on day 14 (>1 ng/ml). The P4 levels on day 26 (initiation of ovsynch protocol) were 1.01 ±0.08 and 0.96 ±0.14 in pregnant buffaloes and levels increased significantly on day 33.Thereafter the mean progesterone level dropped suddenly on day 9 and day of AI. These levels again increased significantly on day 21 post AI in pregnant buffaloes whereas it decreased significantly in non-pregnant buffaloes both in farm and field. There was no significant difference between breeding and low breeding in pregnant buffaloes in both farm and field conditions.
In the present study, the mean progesterone level during different periods of treatments in POVS group was in agreement with the findings of
Colazo et al., (2013) who recorded the mean P4 levels (ng/ml) as 0.4±0.09 in buffaloes of farm conditions during the breeding season, while,
Hoque et al., (2014) observed the mean progesterone (P4) levels on day 0, day 12, day 22 post AI as 0.64±0.36, 1.47±0.33 and 2.14±0.13 ng/ml, respectively in buffaloes that ovulated and became pregnant under field conditions.
Conception rate
Comparatively the per cent conception rates at induced/observed estrus, 2
nd and 3
rd service were higher in POVS group (42.85 vs 39.13; 14.28 vs 8.69 and 7.14 vs 2.1) as compared to DPG group, respectively in farm condition. While, the per cent conception rate at induced/observed estrus, 2nd and 3rd service were higher in POVS group (32.60 vs 32.16; 15.21 vs 11.18 and 6.52 vs 3.14) as compared to DPG group, respectively in field condition.
In the present study the overall conception rate in DPG group of buffaloes under farm conditions during the breeding season was on par with the observations of
Rahman et al., (2012) and
Honparkhe et al., (2008) who reported the conception rate as 64.70 and 65.6 per cent, respectively, whereas the present findings are in contrary with findings of
Esposito et al., (2019) and
Yendraliza et al., (2019) who recorded a higher conception rate (75.00 and 70.00%, respectively). On the contrary, DPG group buffaloes of the present reared under farm conditions during the low breeding season showed lowered conception rate when compared to the previous findings of
Phani (2017) who recorded a higher conception rate (86.66%).
In the present study, the overall conception rate in POVS group buffaloes under field condition during the breeding season was in tune with the findings of
Konrad et al., (2013) who found the conception rate as 55.80 per cent. Whereas,
Ravikumar et al., (2014) observed a higher conception rates during breeding (70.00%) and low breeding seasons (50.00%) under field conditions.
The present findings evidently explained that higher conception rates in postpartum subestrus buffaloes might be due to pre-synchronization with prostaglandin analogue that caused lysis of the CL before the initiation of Ovsynch protocol. This resulted in most the buffaloes being in mid luteal phase at the time of initiation of Ovsynch protocol, so that the first GnRH helped in luteinization and/or ovulation of follicle administration of PGF
2α alpha on 7
th day lead to lysis of CL and resulting in initiation of new follicular wave. The second GnRH injection allowed maturation and ovulation of Graffian follicle in turn improved the conception rate as opined by
Mendonca et al., (2019).