Effect of Sex Sorted Semen in Synchronized Estrus on Pregnancy Rate and Female Ratio in Gir Cows

Gir cow is considered as the best breed due to its superior qualities and best milker among Indigenous cattle.  In India presently, Indigenous cow’s ghee and urine is considered useful for making medicines based on Panchgavya and used as a best mixture in Ayurved (Parkavi et al., 2021). Its milk is of premium quality milk due to the presence of A-2 beta casein and has more demand in urban educated pepoles. The average milk yield of Gir cows is 1930 litres in 300 days, average age at first heat and calving were 1149 and 1534 day, respectively while average dry period and inter-calving period were 123 and 423 days, respectively. At present there is huge demand for Gir cow females in India however, prolonged inter calving period, more inseminations per conception and post-partum anestrus are the predominant reproductive disorder that limit the birth of more females in cows. 

Reduced reproductive efficiency leading to prolonged inter calving period is one of the most important causes of economic losses in livestock (Sewalem et al., 2008). For archiving maximum reproductive efficiency, each cow must be reproduced as frequently as possible and maintain a standard inter-calving period of 12 months. Various management strategies and estrus synchronization protocols are implemented to induce estrus and ovulations in cows. Ovsynch is one of the estrus synchronization protocols consisting of two injections of gonadotropic releasing hormone (GnRH) combined with single administration of prostaglandin F2α (PGF2α) and used in cyclic animals for synchronization of ovulation and fixed time artificial insemination (Singh, 2014). The main advantage of Ovsynch protocol is estrus synchronization can be done at all the stages of estrus cycle and synchronization of estrus as well ovulation which occur are very effective for improving reproductive performance (Paul and Praksh, 2005).

The predetermining of sex has valuable impact on livestock industry because of its economic gains with objective to obtain a calf of a particular sex. Use of sorted semen decouples the number of replacement of heifers required for milk production and increases the rate of genetic progress. Sexed semen is generally accessible now however, the main factors in the degree of utilization of sex sorted semen are pregnancy rate, per cent of female calves born and cost of calf production.

The growing demands for Gir females can be achieved by application of sex sorted semen in spontaneous estrus as well as in synchronized estrus. Considering the above paucity and meager research on use of sex sorted semen in estrus synchronized Gir cows in India, the present research work was conducted to study the pregnancy rate and female ratio of sexed semen in estrus synchronized Gir cows with Ovsynch protocol.

The present research work was carried on twenty lactating multiparous Gir cows from Adarsh Gorakshan farm Mhaispur, at farmer’s doorstep in nearby villages in Akola and at Department of Animal Reproduction, Post Graduate Institute of Veterinary and Animal Sciences, Akola.

The average age was 5.9 years, average milk yield was 6.4 litters per day and average parity was 3.2 in selected cows. The vaccination and deworming status, any reproductive abnormalities and last date of parturition were recorded. The Gir cows that have completed post-partum period of sixty days with normal reproductive genitalia, without clinical as well as subclinical infection were selected randomly. All cows were housed in shed with clean dry flooring system. The cows were sent in open for grazing from 10 am to 3 pm and provided compounded concentrate according to milk yield. All cows were provided with fresh drinking water twice daily.

The selected Gir cows were examined gynaeco-clinically and cows with palpable ovarian structure like follicle and corpus luteum were divided irrespective of age, milk production and parity. All the selected multiparous Gir cows were dewormed using injection Ivermectin @ 1 ml per 50 kg body weight subcutaneously, initial treatment with injection vitamin AD3E and H, 5 ml I/M and supplemented with chelated mineral mixture (1 kg) 50 gm daily orally after first gynaecological examination. These randomly selected cows were divided into two groups (n=10).
 
Group- I (Ovsynch with sex sorted semen)
 
One week after presynchronization treatment, cows from
this group were treated with Ovsynch protocol with Inj. Buserlin acetate 10 µg on day first Inj. Cloprostenol Sodium 500 µg on day 7 and Inj. Buserlin acetate 10 µg i/m on day 9 and inseminated with sex sorted Gir bull semen.
 
Group- II (Ovsynch with conventional semen)
 
One week pre synchronization treatment, cows from this group were treated with Ovsynch protocol with Inj. Buserlin acetate 10 µg on day first Inj. Cloprostenol Sodium 500 µg on day 7 and Inj. Buserlin acetate 10 µg i/m on day 9 and inseminated with conventional Gir bull semen. 

The cows were observed for estrus exhibition after the injection of PGF2α (d 7) and different estrus symptoms like congestion of vaginal mucus membrane, vaginal discharge and tumification of vulva were noted by visual observations in the morning and evening. Gir bull conventional and sex sorted semen straws were purchased from Bhartiya Agro Industries Foundation (BAIF) Development Research Foundation, Uruli Kanchan, Pune (M.S.) India which were stored in Liquid Nitrogen (LN2). In both the group, inseminations were carried out after 16-20 hrs of last GnRH injection. The pregnancy diagnoses were carried out by per rectal (P/R) examination in inseminated buffaloes after two months. The pregnancy rate of sex sorted semen and conventional semen groups were analyzed by Chi-sequare test by using software WASP of ICAR, Goa.

Efficacy of Ovsynch protocol in Gir cows
 
Efficacy of estrus synchronization was recorded to be 100.00 per cent in present study for Gir cows treated with Ovsynch protocol in both groups (Table 1). The Gir cows showed better treatment response for Ovsynch protocol. These findings are in harmony with earlier results reported by Ammu et al., (2012) in anestrus Gir cows, Dhami et al., (2015) in cross bred anoestrus cows, Barolia et al., (2016) in repeat breeding Gir cows.


 
Estrus signs in Ovsynch protocol in Gir cows
 
Estrus signs such as tumification of vulvar lips, vaginal discharge and congestion of vaginal mucus membrane were recorded in the Ovsynch synchronized Gir cows. The tummification of vulval lips symptom was shown by 60 percent (6/10) cows and 50 per cent (5/10) cows in Group I and II, respectively. Congestion of vaginal mucus membrane shown by 70 per cent (7/10) cows and the signs of vaginal discharge was shown by 60 (6/10) per cent cows in both the groups. Congestion of vaginal mucus membrane sign was predominantly shown by Gir cows in Ovsynch synchronized estrus.

The findings observed in the present research are not in harmony with Stevenson et al., (1996) reported signs of nervousness, mucous discharge and occasional mounting activity in only 3 of 85 cows (3.5 per cent) in Ovsynch protocol in buffaloes. Kundalkar et al., (2014) reported the estrus signs like congestion of vaginal mucous membrane were exhibited by 87.50 (7/8) per cent, tumification of vulva by 50 (4/8) per cent and vaginal discharge by 37.50 (3/8) per cent by buffaloes synchronized with Ovsynch protocol in buffaloes. 

Neglia et al. (2003) that reported 88 per cent of Italian Mediterranean buffaloes had a tonic uterus on the day of AI which treated with Ovsynch protocol. The variation in the estrual signs shown may be due to variation in species, breed, season, feeding and management, frequency of estrus detection and yield of animals.
 
Pregnancy rate of sex sorted and conventional semen in Gir cows
 
The pregnancy rate was lower after AI with sex sorted semen (40%) than conventional semen (50%) and results are non significant (P<0.05). There was no difference between sex sorted and conventional semen for calving rate. The average pregnancy and calving rates for sex sorted semen AIs were 40% and 100% and for conventional semen AIs were 50% and 100%, respectively. The proportion of female calves born from sex sorted semen AI was 75% and from conventional semen was 60%. The proportion of live calves born from sex sorted and conventional semen AI was 100% (Table 1).

Pregnancy rate for sex sorted semen obtained in present research work was similar to those obtained by Sharma et al., (2018) who observed 40% pregnancy rate in cows. Joshi et al., (2021) observed the overall conception rate of sex sorted semen was 39.92±0.5 per cent which is similar to present research findings.

In concurrence with present research findings, Weigal, (2004) reported higher pregnancy rates for sexed semen in Jersey and Holstein heifer 43% and 46% at dose of 1.5x10⁶ and 6x10⁶ respectively. Presicce et al., (2005) observed 42.8% at dose of 4x10⁶, Borchersen and Peacock, (2009) reported pregnancy rate in Holstein, Jersey and Red breed as 49.3%, 46.6% and 60.2%, respectively. DeJarnette et al., (2010) observed pregnancy rate of 44% and 46% at dose of 2.1x10⁶ and 3.5x10⁶. Lu et al., (2010) recorded 69.7%. DeJarnette et al., (2011) observed 44% at dose of 10x10⁶. Gaviraghi et al., (2013) observed 49.8%, 48% and 47% at dose of 4x10⁶, 6x10⁶ and 8x10⁶, respectively. Kurykin et al., (2016) reported pregnancy rate in induced estrus AI (41.7%) which is lower than spontaneous estrus AI (53.4%).

Lower pregnancy rates in sex sorted semen than the results of present findings were recorded by Doyle et al., (1999) 31.8% andersson et al., (2004) recorded 21% at sperm dose of 2x10⁶. Weigal (2004) observed 31% in Jersey cows. Andersson et al., (2006) observed 21%, Norman et al., (2010) reported 39%. DeJarnette et al., (2011) observed 38%, Rhinehart et al., (2011) observed 38% in heifers and 33% in cows. Gaviraghi et al., (2013) reported 31.2%. Healy et al., (2013) and Mallory et al., (2013) observed 31.6% and 38%, respectively. Karakaya et al., (2014) recorded pregnancy rate at day 31 and at day 62 as 31.8% and 25.7%, respectively. Abdalla et al., (2014) recorded 34% and 32.2% at day 40 and 90, respectively and Patel and Jethwa (2019) observed 39.53% pregnancy rate.

Pregnancy rate for conventional semen insemination obtained in present research work was similar to those obtained by Sharma et al., (2018) who recorded 49.32%. In comparison with present research findings, the higher pregnancy rates were recorded for conventional semen by Weigal (2004) reported 62% at dose of 20´106 in New-York, in Jersey 61% at California. Bodmer et al., (2005) observed 59.3% at dose of 2x10⁶. Borchersen and Peacock (2009) reported pregnancy rate in Holstein, Jersey and Red breed as 61.9%, 53.9% and 65.4%, respectively. DeJarnette et al., (2010) observed 61% at dose of 15x10⁶. Norman et  al. (2010) recorded 56% in heifers. De Jarnette et al., (2011) observed 55% and 60% at dose of 2.1x10⁶ and 10x10⁶ respectively. Gaviraghi et al., (2013) recorded 54.9% at dose of 2x10⁶. Mallory et al., (2013) observed 68%. Djedovic et al., (2016) recorded 55%.  Abdalla et al., (2014) recorded 62.5%, 57.8% at day 40 and day 90 of pregnancy. Dowad and Elbaz (2020) recorded 61.47% pregnancy rate in heifers.

While lower pregnancy rates in conventional semen than result of present study were recorded by Doyle (1999) 40.9% andersson et al., (2004) observed 32% and 46% at dose of 2x10⁶ and 15x10⁶, respectively. Anderson et al., (2006) observed 46%, Healy et al., (2013) and Karakaya et al., (2014) observed 39.6% and 39%, respectively. The variation in the pregnancy rate may be difference in species, breed, parity, managemental conditions, season, body condition score, exogenous supplementation of hormones and time inseminations.

The proportion of female calves born after application of sex sorted semen recorded in the current study is lower than other earlier reports obtained by Andersson et al., (2006) 82%, Healy et al., (2013) 86%, Abdalla et al., (2014) 89.6%, Lu et al., (2015) 87.6%, Sharma et al., (2018) 82.14% and Patel and Jethawa (2019) 86.15%. The female calves born after insemination with conventional semen in current study is higher than the earlier reports by Andersson et  al. (2006) 49%, Healy et al., (2013) 48%, Abdalla et al., (2014) 50% and Sharma et al., (2018) 50.68%.

The Ovsynch is effective protocol for estrus synchronization and the sex sorted semen may be used in Ovsynch protocol in Gir cows.