Behavioural signs of Estrus
In this study, estrus behaviour and their intensity were recorded for data interpretation and the score card of different oestrus sign was allotted in intense (31-36), intermediate (19-30) and weak (12-18), respectively in accordance with
Bhattacharyya et al., (2017).
In the present study, mounting or to be mounted by other animals was observed in more than 70% of the animals and sniffing, licking of genitalia and Flehmen’s reaction was recorded in 66.67% of treated animals. The other parameters like bellowing, restlessness, milk yield reduction, frequent micturition and Flehmen’s reaction were observed in 44.44%, 55.56%, 44.44%, 55.56% and 66.67%, of the cows respectively.
The majority of Bachaur cows exhibited 77.78% mounting, allowing mounting by other animals with attempt to mount milkers, followed by sniffing tried to lick with Flehmen’s reaction 66.67%, more restlessness 55.56 % and continuous bellowing 44.44%. In the present study, 44.44 % continuous bellowing was observed in Bachaur cows. In our study, the bellowing activity and homosexual mounting on other cows was comparable with the findings of
Madhavatar et al., (2023), who reported the intense bellowing activity by the cows with higher level of blood estrogen due to seasonal effect.
Restlessness in the treated animals was recorded 55.56% which was less than the report by
Layek (2010) in Sahiwal cows (68.96%) however, restlessness was reported by
Gunasekaran et al., (2008) in crossbred cattle (45.59%). In Bachaur cows, mounting by other animals with attempt to mount milkers was observed in 77.78% of animals which is less than that reported previously in Kankrej cows (100%) by
Madhavatar et al., (2023).
In Bachaur cows, reduction in milk yield and frequent micturition were 44.44% and 55.56% respectively, which is in accordance to the observations of
Madhavatar et al., (2023) and
Gunasekaran et al., (2008). In the present study 55.56% Bachaur cows exhibited frequent micturition during estrus, which was higher than that reported by
Mangal (2009) and
Layek (2010) in Sahiwal cows and
Ansari (2011) in Deoni cattle.
Physical signs of estrus:
The most appreciable physical sign of estrus recorded was intense swelling of vulva (88.89%) in this study. The incidence of intense hyperaemia of vulva, copious estrual mucous discharge, pronounced tonicity of uterus, completely dilated os cervix and presence of large palpable follicle on the ovary was recorded as 44.44%, 55.56%, 66.67%, 77.78% and 66.67%, respectively.
The intense swelling of vulva in Bachaur cows was observed in 88.89% which is in accordance with the findings of
Kumar et al., (2009) in Haryana cows. The vulva of the cows is generally wrinkled or occasionally looks smoother in non-estrus cows. Around the estrus period in cows, clear stringy mucus discharges seen either on the resting ground or on the perineal region (
Keown and Kononoff, 2007). In this study, estrual discharge recorded was copious (55.56%), scanty (33.33%) and no discharge in 11.11% of cases. In many treated animals during estrus, scanty to no discharge was observed in cows which were examined 14 to 16 hrs after the start of the behavioural estrus signs. In few cows copious discharge was found within 12 hrs of estrus at the time of examination. These observations are in accordance with previous findings in cows (
Deshpande, 1982) and Goat
(Bhattacharyya et al., 2000), who reported that estrual mucous discharge was copious in early stage of estrus and scanty or absent in late stage of estrus due to circulatory levels of estrogen in blood (
Mangal, 2009).
In our study large follicle and small follicle were palpated in about 66.67% and 33.33% cases respectively. The palpation of the ovarian follicle depends on the stage of the animal estrus. These observations are in accordance with the findings of
Bhattacharyya et al., (2017).
Estrus intensity, Duration of estrus and oestrus cycle length
The estrus intensity, duration of estrus (Hrs) and Oestrous cycle length (Days) were recorded and was observed that estrus intensity was intense in 6 out of 9 animals (66.67%), intermediate in 2 out of 9 animals (22.22%) and weak in 1 out of 9 animals (11.11%). The estrus intensity in Ongole and Sahiwal cows reported by
Naidu and Rao, (2006) and
Layek (2010), was lower than the present findings but weak estrus was higher in Ongole and Sahiwal cows as compared to the Bachaur cows.
The mean duration of estrus in Bachaur cows was 19.22±0.64 hrs with a range of 16 to 21 hrs.
Mattoni et al., (1988) observed in non-lactating Zebu cattle, the estrus duration (7.66±4.68) hrs was lower than the reports of our present study in Bachaur cows. The similar findings were also reported by
Naidu and Rao (2006) in Nellore (Ongole) cows.
The mean overall oestrus cycle length in Bachaur cow was 21±0.67 days. The minimum duration of 18 days and maximum duration of 24 days was observed in estrous cycle length of Bachaur cows in the present study.
The higher estrus interval reported in Peranakar Ongole cattle by
Imron et al., (2016) was comparable with the present findings of Bachaur cows (21±0.67 days).
Siregar et al., (2016) reported estrus interval of 17.8±0.4 days in Aceh cattle which was lower than the present study. These variations might be due to variation in follicular wave patterns (
Sirosis and Fortune, 1988).
