Kidding rate
In the current study, the kidding rate in vaginal sponge group (group I) during winter and summer season were 60.00 and 55.00 per cent (Table 2). It was similar to the kidding rate obtained in control group (group VI). Similar kidding rate was recorded by
Simoes (2015) and
Inwati et al., (2022) in goats. The results of the present study indicated that intravaginal sponge effectively controlled the strus and fixed time breeding resulted in improved kidding rate as indicated by
Selvaraju and Kathiresan (1999) in Malabari goats.
During the winter and summer season the ovsynch treated groups (group II) exhibited 75.00 and 65.00 per cent kidding rate, at respective seasons.
Holtz et al., (2008). In ovsynch treated groups,
Inwati et al., (2022) and
Panicker et al., (2015) recorded 58 per cent kidding rate. The increased kidding rate in this experimental group might be related to the start of protocol during early to mid-diestrum
(Vasconcelos et al., 1999). The ovsynch protocol when started during mid diestrum, the pregnancy rates were higher because of higher incidences of ovulation after the first GnRH injection
(Cartmill et al., 2001).
In the current experiment, during winter and summer season the overall kidding rates in ovsynch with vaginal sponge group (group III) were 80.00 and 70.00 per cent, respectively.
Nur et al., (2013) reported 24.00 per cent kidding rate following ovsynch plus sponge treatment in nulliparous Saanen goats. In this study, among all the groups, ovsynch with sponge groups (group III) obtained the highest kidding rate. The continuous release of progesterone from vaginal sponge between first GnRH and PGF
2α injection may have prevented premature estrus, LH surge and ovulation
(El-Zarkouny et al., 2004). Hence, inclusion of intravaginal sponge in ovsynch protocol in Tellicherry goats increased the kidding rate in both the seasons
In this investigation, during winter and summer seasons 70.00 and 60.00 per cent kidding rate was achieved in co-synch treatment (group IV). However,
Carba and Velicevici (2013) obtained 57.00 per cent pregnancy rate in cows treated with co-synch treatment. The result of the study indicated that Co-synch protocol proved to be effective in increasing the kidding rate when compared to control goats.
In group V of this study, the overall kidding rate in winter and summer season was 75.00 and 65.00 per cent, respectively.
Nur et al., (2013) stated that the kidding rate following co-synch plus sponge treatment in Saanen goats was 38.00 per cent only. In co-synch protocol inclusion of the intravaginal sponge improved the kidding rate as that of ovsynch plus sponge group in this study. Administration of second GnRH 16-18 hours prior to breeding in ovsynch protocol might have stimulated LH surge appropriately and it might have followed by the fixed time breeding to increase the kidding rate as described by
Holtz et al., (2008).
The natural service in groups I to VI resulted in 80.00 and 70.00 per cent overall kidding rate in winter and summer season. In both seasons in all the groups including control group natural service resulted in higher overall kidding rate than artificial insemination. It indicated that the method of breeding following synchronization of ovulation influenced the kidding rate. In general, natural service group of all synchronized and control groups showed higher percentage of kidding rate when compared to artificial insemination groups.
Ritar and salmon (1983) and
Ritar et al., (1990) attributed the lesser conception rate in goats with AI to the sperm concentration in the semen used for AI and problem with the transport of frozen-thawed spermatozoa through the reproductive tract of the goat.
In the current investigation the overall kidding rate during winter and summer in Tellicherry does was 70.00 and 61.66 per cent, respectively. All the groups including control had higher kidding rate during winter than summer. It was evident that the kidding rate following synchronization of estrus /ovulation was influenced by the seasonal factors. In this study, during winter season, the increased overall kidding rate would be related to the availability of green fodder
(Ahamad et al., 2014), cool environment and absence of heat stress (
Mellado and Meza-Herra, 2002).
Fecundity rate
In this study, there was a marked improvement in the fecundity rate in all the treated groups when compared to the control group in both the seasons (Table 2). In the treatment groups the fecundity rate ranged from 1.6 to 1.75 per doe in winter and 1.40 to 1.60 in summer season. These results were in agreement with those of
Bretzlaff and Madrid (1989),
Selvaraju and Kathiresan (1999) and
Nasroallah et al., (2012) in goats treated with synchronization of estrus/ ovulation protocols. However,
Nur et al., (2013) reported the fecundity rates as 1.2 and 1.4 in ovsynch plus sponge and co- synch with sponge treated goats respectively. The results of the present study clearly indicated that all the synchronization of ovulation protocols followed in this study regularized the ovulation and their timings in relation to the fixed time breeding and it might be the reason for increased fecundity rate in treated groups
(Holtz et al., 2008). Among the treated groups, the ovsynch with sponge (group III) in winter and summer seasons had the maximum fecundity rate in this study. Injection of GnRH prior to breeding and inclusion of progesterone between first GnRH and PGF
2α injection might have caused closer synchrony of ovulation and resulted in increased fecundity rate in this group
(Nur et al., 2013).
The overall fecundity rate in summer and winter was 1.43 and 1.60 per doe. It indicated that increased serum cortisol levels during summer might have affected the ovulation response or might have caused early embryonic death (
Khan and Ludri, 2002). These observations were attributed to the reduction in number kids produced during summer.