On the basis of data collected from questionnaire in Group I, the optimum age of puberty in Chippiparai bitches was10.104±0.199 months which ranged between 7-15 months and age of first mating was 3.85±0.12 years and ranged between 1.5-6.5 years. Owners maintaining the female for breeding purpose allowed first mating at 1½ to 2 years of age. But the owners rearing this breed for hunting and sporting purposes allowed mating at around 4-6 years of age, subsequently the number of parities per female was 3.33±0.11 times, which was in agreement with the observation of
Karthickeyan et al., (2015) who reported that the decreasing population of Chippiparai dog was to be conserved by educating the pet owners by eliminating the myths involved in breeding. Present study revealed that the inter-estrus period in Chippiparai female was 11.57±0.099 months (10-14 months) which is in agreement with the finding of
Karthickeyan et al., (2015) who reported that Chippiparai bitches whelp only once in a year. In present study, length of proestrus bleeding was recorded as 7.37±0.24 days (3-15 days). Vulval bleeding was a characteristic proestrus sign with a duration of 6 to 11 days (9 days on average) but could be used as a reliable parameter to determine the optimal time of mating
(Fledman and Nelson, 2007). As per data of Group I, the number of matings allowed by the Chippiparai pet owners was 1.35±0.06 times with a range of 1-3 times per cycle. Some of the pet owners allowed one mating per cycle and believed that frequent mating reduced the hunting performance of male or female dogs. In Group I, the length of gestation period was recorded as 60.8±0.2 days (58-68 days) which was in agreement with the findings of
Mutembei et al., (2000) and mean litter size was recorded as 4.028±0.214 pups ranging from 1-12 pups per whelping. The owners adopting one mating per cycle had low litter size, on the other hand breeders who followed multiple matings had 8-10 pups per whelping which was in disagreement with the observation of
Karthickeyan et al., (2015) who recorded the litter size as 4-10 pups in this breed.
Linde-forsberg (1994) reported that litter size was highly correlated to optimum timing for breeding and less number of matings could be the reason of small litter size under orthodox breeding system. In this study the sex ratio male:female was estimated as 1.6:1.
Sorribas et. al. (2018) reported 1.08 males were born per female born in Labrador breed. In the present study 91.7%, 4.8% and 3.5% of pregnant bitches experienced eutocia, dystocia and caesarean section, respectively (Table 1). The incidence of dystocia (8.3%) was lower compared to Labrador (15.5%)
(Sorribas et. al., 2018), Golden Retriever (9.1%), Pekingese (85.7%)
(Gill, 2002) and Boxer (32%) breeds
(Linde forsberg and Persson, 2007). The low frequency of dystocia in Chippiparai dog compared with these breeds was probably due to its size and body characteristics (mesomorphic and mesocephalic), which made delivery easier than other breeds. Live percentage of pups in present study was 83.7%, followed by still birth (2.8%) and pups that died before weaning (13.5%), the incidence of pup mortality was more in the litters that underwent dystocia was in agreement with the finding of
Rajendran et. al. (1992). In Group I, the conception rate was 53.57% (Table 1) due to the myth that pregnancy reduced the hunting and racing performance of young bitches. This finding was in agreement with the observation of
Fontbonne (2011) who reported 50% conception rate in French Kennel Club with incidence of infertility as 40% to 80% due to mistimed mating. This study revealed that the dogs were maintained mostly on non-vegetarian food, along with rice, egg and milk. Majority of the breeders (80.5%) followed twice a day feeding (morning and night). Present study revealed that 60% of Chippiparai dog owners maintain this breed for sport and hunting purposes due to its heat tolerance capability and higher resistance from communicable infectious diseases
(Karthickeyan et al., 2015). This breed was generally reared in backyard with no special housing system and 2-5 animals were maintained together.
Karthickeyan et. al. (2015) reported that no scientific housing and management were adopted for this breed. Present study revealed that the mating with litter mate (11.5%), within village (63.8%) and outside village (24.7%) (Table 1) were being adopted by the Chippiparai dog owners. Mating with litter mate and within village resulted in inbreeding. These findings are in agreement with the observations of
Karthickeyan et. al. (2015) who reported the mating with litter mate was a common practice in the breeding management of this breed.
In Group II, the length of the stages of estrous cycle had been differentiated according to the percentage of parabasal, intermediate, superficial and squamous cells (Table 2). In present study the average length of cytological proestrus (Fig 1 and 2), estrus (Fig 3 and 4), diestrus (Fig 5) and anestrus (Fig 6) were7.64±0.129, 8.95±0.184, 64.74±0.41 and 213±1.42 days, respectively. Under estrogen influence, during proestrus and early estrus, the cells of the vaginal epithelium begin to proliferate, differentiate, thicken and exfoliate
(Klaas, 1985). The inter-estrus interval was estimated as 294.57±1.4 days, which was in agreement with the observations of
Raja et. al. (2017) and
Karthickeyan et. al. (2015). In Group II the percentage of superficial and squamous cells in vaginal smears were above 80% (Fig 3) on day 6.68±0.184. The animals were allowed for natural breeding, when the superficial cell Index (SCI) and karyopyknotic Index (KPI) was 100% and 80% (Fig 4), respectively on day 9.37±0.21. Average number of breedings allowed were 3.44±0.074 at three days interval until the female showed refractoriness (onset of diestrus), as recognized by the appearance of parabasal cells (>80%), neutrophils and superficial and squamous cells decreased to 20% (Fig 5). These findings were in agreement with the reports of
Leigh et. al. (2013) and
Arlt (2018).
Klaas, (1985) who also found that, as proestrus progresses the SCI will rapidly approach 100% and remained high throughout the estrus. The KPI increased slowly and reached 80% by estrus and then increased to 100% at ovulation. Both SCI and KPI would fall sharply after ovulation at the onset of diestrus, which was in agreement with our study. In Group II, the conception rate and litter size were considerably improved to 85% and 7.54±.141, respectively (Table 4) which were significantly higher than Group I. Optimum time of mating and frequency of mating played a key role in improving the conception rate and litter size
(Zoldag et. al., 1993; Johnston et. al.,1994; Antonov, 2017).
In Group III, the serum concentration of progesterone in Chippiparai bitches increased from 0.58±.05 ng/ml (Table 3 to 5) on the first day of proestrus bleeding to 1.02±.04 ng/ml by late proestrus, these findings gained support from the reports of
Reddy et al., (2011) who reported the plasma progesterone level as 0.37±0.07 ng/ml on the first day of proestrus and recorded it as 1.55±0.19 ng/ml on day 8 of proestrus. The serum progesterone concentration in Chippiparai females was recorded as 1.57±0.073 and 2.56±0.1 ng/ml (80% SCI and 100% SCI, respectively) during early estrus followed by 6.88±0.315 and 8.9±0.28 ng/ml (Day 0 and Day 3 of 100% KPI) and concentration of progesterone increased to 11.05±0.36 ng/ml (Day 6 of 100% KPI), these findings are in agreement with the observations of
Jeffocate (2004), who reported rise in progesterone level at the time of LH surge to 1-2 ng/ml and reached to 2-4 ng/ml two days later (on the day of ovulation) and on the day four from the LH surge (onset of the fertile period) circulating progesterone increased up to 6-10 ng/ml. Further, the level of progesterone had risen to 18.15±0.7 ng/ml on day one of diestus stage, which was identified by the refractoriness of female and cytologically >80% parabasal cell and numerous neutrophils. On the day 15, 30 and 60 from 100% KPI the mean progesterone concentration was 55.72±4.5, 97.98±4.5 and 26.08±2.4 ng/ml, respectively and serum progesterone concentration on day 90 was 1.035±0.12 ng/ml and reduced to undetectable level of <1 ng/ml on day 120 (Table 3) which coincided with the reports of
Concannon et al., (1975) and
Jeffocate (2004), who reported low progesterone level of 1 ng/ml by day 90 after LH peak and further reduced to baseline (<1ng/ml) during inter-estrus interval.
In Group III, natural mating was allowed when the blood progesterone level was > 4 ng/ml and <12 ng/ml at three days intervals.
Arlt (2018) reported that, it was more reliable to assess vaginal exfoliative cytology repeatedly and based on its findings progesterone was estimated to accurately predict the time of ovulation (2-4 ng/ml) and fertile period in bitches. In present study, 100% SCI and KPI during VEC were used as landmark for onset of estrus and ovulation, respectively
(Klaas, 1985) and were prerequisite for progesterone estimation. Further, the conception rate and litter size increased up to 91.66% and 7.9±0.34 pups, respectively by using VEC and blood progesterone concentration as the diagnostic tool to estimate optimum breeding time in Chippiparai bitches which was in agreement with the findings of
Johnston et. al. (2001) and
Antonov (2017).
In this study the conception rate recorded in Group II (87%) and Group III (91.66%) was significantly higher than Group I (53.57%) which were in agreement with
Reddy et. al. (2011) and
Arlt (2018).
