Efficacy of intravaginal progesterone added to Ovsynch in Algerian cattle farms

A Noui and A Boucif

Institute of Veterinary Sciences, Ibn Khaldoun University, BP 78, 14000, Tiaret, Algeria Laboratory of farm animal reproduction
aboucif30@yahoo.fr

Abstract

This study was conducted to evaluate the reproductive performance at estrus detection in post-partum anestrus cows following treatment with controlled internal drug release (CIDR) and Ovysynch or with Ovsynch protocol alone. Seventy (70) gyneco-clinically intact multiparous cows (40 Montbeliarde and 30 Holstein) were divided into two equal groups (35 cows each) in June when many cows (67%) were in anestrus. The cows in group 1 (n=35) were treated with Ovsynch alone. They were treated with inj GnRH 100 μg (Cystoréline) at day 0, inj PGF2α 25 mg (dinoprost) at day 7 and inj GnRH 100 μg at day 9 intramuscularly. The cows in Group 2 (n=35) were treated by Ovsynch plus CIDR protocol. The progesterone device (CIDR) was inserted on day 0 and removed at the time of PGF2 α injection on day 7. The cows that exhibited estrus were inseminated 12 to 18h after PGF2α injection in both protocols.

The estrus response for CIDR-treated cows was greater (80.0%) than for no-CIDR-treated cows (48.6%). The pregnancy rate at day 30 post insemination was lower for Ovsynch alone cows (31.4%) than for Ovsynch plus CIDR treated cows (57.1%). The protocols obtained conception rates of 71.4% (group 2) and 64.7% (group 1) with a statistical difference. Thus, the conception rate could be increased by controlled breeding using CIDR added to Ovysynch protocol in cows mainly in anestrus.

Keywords: cow, CIDR, conception rate, estrus, PGF2α, pregnancy rate, reproduction

Introduction

The estimated number of cattle in Algeria is less than two million. Thus cattle occupies the third place after the sheep and goat herd, and represents 6% of the total national ruminant herd (MADRP 2016).

Three types of hormonal treatments can be used to synchronize heat in cattles (Ashit Kumar et al 2015): 1. prostaglandin-based treatments and F2α or its analogues, 2. others combining to GnRH and PGF2α and 3. Progestin-based treatments (a device that releases progesterone or norgestomet and/or PGF2α and eCG).

Thus a good knowledge of the physiological mechanisms explaining the effect of each treatment will facilitate the management of breeding cows via artificial insemination (AI). Almost all programs involve strategically timed treatment of prostaglandin F2α (PGF) and gonadotropin releasing hormone (GnRH) which the basic program is the “Ovsynch” regimen. Although the original studies using this combination were conducted and reviewed by Thatcher et al (1991), it was the comprehensive studies by Pursely et al (1997) that demonstrated the suitability of the basic “Ovsynch” protocol.

However, one of the major constrains of profitable dairy farming is the low pregnancy rate in cows Shamsuddin et al 2001). Low rates and accuracy of estrus detection also are major factors limiting in reproductive efficiency of dairy cows (Macmillan 2010; Paul et al 2011).

On the other hand, the productivity of cattle could be low because of poor nutrition witch the specific reasons for the decline have not been documented. These might be directly related to or exacerbated by environmental and management conditions (Alam et al 2006).

To increase the reproductive efficiency in dairy cows, various estrus synchronization protocols using Progesterone and implant or intravaginal device associated to PGF2α are the alternative strategy to bypass the critical problem of estrus detection and to increase pregnancy rates of dairy cattle under a variety of management systems (Jayaganthan et al 2016). However, the CIDR is an effective method that is convenient to use in case of poor heat detection on primiparous or multiparous cows particularly suitable for non-cycleous females. To my knowledge, no study has been edited on this subject in Algeria.

This study aims to assess the effect of Ovsynch alone and Ovsynch plus CIDR protocol (day 7) on the reproductive performance of cows in Algerian dairy cattle.

Materials and methods

This study was conducted on a private dairy farm in Setif area (Algeria) at an altitude of 1 080 m.

Animals and trials

The estrus synchronization after a Gonadotropin releasing hormone (GnRH) treatment at controlled internal drug releasing device (CIDR) insertion (CIDR® 1,9 g, Pfizer Animal Health, France) was investigated in an Algerian cattle farm.

70 postpartum anestrus cyclic multiparous cows (40 Montbeliarde and 30 Holstein cows) aged between 2 to 5 years were selected after thorough gyneco-clinical examination for their reproductive status as illustrated in the timelines in Figure 1. The Montbeliarde is the most represented in the population (57%) followed by the Holstein with 43%. The cows had body condition scores 2 to 3 (according to Campanile et al 2010) and were between the intervals of 55-90 days postpartum.

The study was conducted from June to September 2016. At the beginning, most of the cows (67 %) were in anoestrus.

They were dewormed using ivermectin, 100 mg S/C and supplemented with a mineral mixture for 20 days before initiating treatment. After selection, the cows were randomly distributed to two treatment groups as Ovsynch with or without CIDR consisting of 35 cows each group. They received the treatments during this period were inseminated (AI) at observed estrus.

The animals in treatment 1 (n=35, 22 Montbeliardes 13 Holsteins) were subjected to the Ovsynch protocol as described by Pursley et al (1995). The cows were administered intramuscularly with injection of GnRH (Cystoreline 100 μg i.m.) on day 0, injection of PGF2α (dinoprost 25 mg i.m.) on day 7 and a second injection of GnRH (Cystoreline 100μg i.m.) on day 9.

The animals in treatment 2 (n=35, 18 Montbeliardes 17 Holsteins) were subjected to the Ovsynch plus CIDR (Internal Drug Release Device, 1.9 g of progesterone, Pfizer Animal Health, France).

The treatments were similar to those used in group 1 except that a progesterone device (CIDR) was inserted on 0 day and removed at the time of PGF2α injection (dinoprost 25 mg i.m.) on 7 day followed by a second GnRH injection (100µg of Cystoreline) administered I/M on day 9) (Figure 1).

The estrus of the cows was synchronized with gonadotropin releasing hormone (GnRH) and prostaglandin F2α (PGF2α). The detection of estrus was based on visual observation. The animals were checked for estrus twice daily at least for 30 min each time.

The estrus signs were recorded (standing to be mounted, bellowing, redness, swelling of vulva and clear mucous discharge). The cows also were confirmed in estrus by the permeability of the cervix of the pistol on the day of insemination.

An artificial insemination (AI) at observed estrus was performed 12 to 18 h after the second GnRH injection or 48 and 72 hours after the CIDR removal in the both protocols as shown in Figure 1.

Figure 1. Schematic representation of the Ovsynch protocol with or without CIDR

Data recorded

The pregnancy was diagnosed by transrectal ultrasound at 30 days followed by a palpation per rectum on day 45 after the artificial insemination.

The reproductive performance variables recorded in this study were determined as follows:

i) Estrous response (percentage of females showing estrus among those treated),

ii) Conception rate (CR, percentage of females conceiving divided by those inseminated in the corresponding group),

iii) Pregnancy rate (PR, percentage of females diagnosed as pregnant divided by the total number of cows in the corresponding group).

Statistical analysis

The data were analyzed with the statistical software program (SAS Version 9.12). The objectives of this analysis were to test the effect of the treatment on estrus response, pregnancy and conception rates for the two treatments. Significant differences in reproductive performance of the cows tested between treatments were determined by Chi-square. The level of significance was set at p < 0.05.

Results

A rectal palpation was carried out in all cows used in this study before PGF2α injection to control the luteal structure.The reproductive performance of synchronized cows as the estrus responses, pregnancy and conception rates are shown at Table1.

The results were better with the CIDR protocol as compared to the Ovsynch protocol alone (Figure 2).

The detection of estrus in our study for the both groups was taken as a response to the treatments after CIDR removal and the second GnRH injection. Regardless of the estrus-synchronization protocol an estrous response was detected in 45 out of the 70 cows treated. However by treatment group, cows that were subjected to Ovsynch alone protocol showed estrus 17 cows (48.6%), while cows that were subjected to Ovsynch plus CIDR protocol showed estrus 28 cows (80%). There was a statistical difference between the two programs.

The cows that responded to the synchronization treatment in both groups were inseminated 12 to 18 h after second GnRH injection.

The pregnancy rate (Table 1) was significantly higher (P<0.05) in CIDR treated group 57.1 % (20/35) as compared to no-CIDR-treated group 31.4% (11/35). This study recorded low pregnancy rate relative to conception rate in Ovsynch group alone.

However, highest synchronized conception rate were recorded in the both protocols (64.7% and 71. 4%) respectively in Ovsynch alone protocol and in Ovsynch plus CIDR group (Figure 2). However, the results revealed greater conception rate in the Ovsynch plus CIDR group than in the Ovsynch group.

Figure 2. Reproductive performance observed in Algerian cattle subjected to Ovsynch protocol with (n = 35) or without (n = 35) CIDR insertion

Discussion

In herds with estrus detection problems, the use of estrus synchronization might improve reproductive performance by eliminating the problems associated with estrus detection (Stevensen et al 1999). It has been also reported that approximately 50% of all estrus behaviors may be not detected during the postpartum period (Mialot et al 1999).

To this end, the signs of estrus should be observed three or four times daily and inseminations should be made once a day. The cows that responded in the current study to Ovsynch protocol were 48.6%. This result is comparable to those reported in several studies estimating that ≤ 50% of the cows were detected in estrus in dairy herds (Udin et al 2017; Kandiel et al 2012).

Despite the applications of different Ovsynch protocols, the percentages of cows showing estrus and fertility were still low because there was a relatively lower estradiol concentration around AI (Shamsuddin 2001).

Therefore, the reproductive performance of cows receiving the ovsynch treatment may be improved if progesterone is administered during the period between the GnRH and PGF2α injections to increase the estrous response and conception rate of cows (Xu et al 1997).

Such progesterone treatment is the key player in the estrus induction and potentiates the action of estrogen which is aided by the regressing CL by secreting some amount of progesterone.

On the other hand, the benefits of a timed artificial insemination (AI) system increase under conditions of poor estrous detection rate and poor conception rate.

The estrus response of CIDR treated cows in the present study was significantly (P<0.05) higher (80%) than that reported in Ovsynch alone protocol (48.6%). Few previous works have calculated the estrus response and reported highest estrus rates (Xu et al 2000; Dhami et al 2014).

It has been observed that the progesterone from the controlled internal drug release (CIDR) was sufficient to increase and maintain a progesterone concentration in blood >2 ng/ml in the absence of CL on ovary (Mann et al 2006; Hammam et al 2013; Suthar et al 2012).

Chebel et al (2010) demonstrated that the use of a CIDR insert for 7 days during a timed AI protocol increased the proportion of functional CL in anestrous cows after AI and pregnancy/AI compared to protocols without CIDR.

Additionally, the progesterone concentration during one estrous cycle affects the endometrial morphology in the subsequent cycle and may decrease the number of hypothalamic estradiol-17 β-receptors by negative feedback (Shaham-Albalancy et al 1997).

Xu et al (2000) studied the progesterone treatment at two times with 7 or 8 days of CIDR insertion. According to these authors, changing the synchronization program from 7 to 8 days altered the pattern of estrous response. Although a good estrus rates was recorded in the two protocols used but the distribution in the onset of estrus was more dispersed at the 7 days program that was preferred because it did not reduce the conception rate at the synchronized estrus (Xu et al 2000).

Different conception rates in dairy cows and heifers after synchronized estrus ranging from 30% to 75% were recorded in the Ovsynch program (Kandiel et al 2012; Udin et al 2017).

This study showed good conception rates for the both groups with a slight superiority in favors of the CIDR treated group (71.4%) compared to the no CIDR treated (64.7%) with a statistical difference.

The result recorded in the Ovsynch program is in accordance with previous reports. On the other hand, other reviews founded lower conception rates compared to our result (Ali et al 2012; Mohd Alyas et al 2013; Raste Garnia and Anvari Savojbolghi 2010; Kawate et al 2004). Lower conception rates were also reported with Ovsynch in non-cycling cows and heifers by Nak et al (2011) and Jayaganthan et al (2016).

On the other hand, Vasconcelos et al (1999) reported greatest conception rates in dairy cows that began the Ovsynch protocol between the days 5 and 12 of the estrous cycle. The conception rate for cows in the Ovsynch plus CIDR group in our present study is in line with the findings of Jayaganthan et al 2016 and Kawate et al 2004. This result was greatest to that documented in other works (Bhoraniya et al 2012; Dhami et al 2014; Patel et al 2013).

Several previous works reported higher conception rate in the Ovsynch plus CIDR group than in the Ovsynch group (Ali et al 2012; Jayaganthan et al 2016; Mohd Alyas et al 2013; Rastegarnia and Anvari Savojbolghi 2010).

On the other hand, other workers also recorded higher conception rate in Ovsynch plus CIDR treated cows compared to Ovsynch treated group but without significant differences between the two protocols (Sakase et al 2005; Schafer et al 2007).

The variations in the conception rate of different workers might be due to differences in breed, climate, nutrition, management and different CIDR protocols (Jayaganthan et al 2016). But the reasons for the reduced conception rate cows in Ovsynch group as compared to cow in CIDR treated group could not be determined in the present study. It is possible that providing exogenous progesterone by the inclusion of a CIDR device improved the conception rates of the Ovsynch protocol in postpartum cows (Revah and Butler 1996).

Previous studies have shown that progesterone concentration in the late luteal phase before insemination is positively associated with conception rate (Xu et al 2000). These observations further supported the previous observations on the use of similar protocols in anestrus cows by many workers (Bhoraniya et al 2012; Chaudhari et al 2012; Dhami et al 2014; Ramakrishnan et al 2012).

The pregnancy rate is the product of estrus detection and conception rates (Shamsuddin et al 2001). In a previous study, the pregnancy rates after the Ovsynch studies in dairy cows varied from 27 to 40% (Neglia et al 2003; Taşal et al 2005). Pursley et al (1997) reported a pregnancy rate of 35.1% and 37.8% in heifers and cows respectively.

The pregnancy rate recorded in the Ovsynch group cows was 31.4% that is in the ranges of the authors stated. It was similar to that reported in recent reviews (Gokhan Dogruer 2010; Kandiel 2012; Kasimanickam et al 2008). However, this result is greater as compared to the findings of Caraba and Velicevici (2013) and Buhecha et al (2016).

On the other hand, higher pregnancy rates were reported by other recents works in the Ovsyynch protocol (El-Zarkouny 2004; Akbarabadi et al 2014; Jayaganthan et al 2016). Such low pregnancy rates relative to conception rates recorded in this study could perhaps be the consequence of the reduced fertility of an aged follicle/oocyte induced by estradiol injection (Pursley et al 1997).

In present study, the pregnancy rate in CIDR-treated cows and inseminated following detected estrus was significantly higher as compared to no-CIDR-treated group (57.1% vs 31.4%, P<0.05). Different studies showed an acceptable pregnancy rate after the use of a 7-d CIDR protocol in combination with GnRH and prostaglandin F2α as was reported by Crane et al (2006) and El-Zarkouny et al (2004).

It has been reported that the addition of progesterone to the Ovsynch protocol improved pregnancy (Stevensen et al 2006).

Our pregnancy results are consistent with the results from previous studies. They were similar to those reported by Akhiro et al (2008) and Jayaganthan et al (2016).

According to Moreira et al (2000), one of the advantages of CIDR for pregnancy rate was probably due to the preventive effect against early ovulation in case that it was initiated by the Ovsynch protocol.

Stevenson et al (2006) also reported that overall pregnancy rates for lactating dairy cows treated Ovsynch plus CIDR were 10 and 5% higher than those treated with Ovsynch at days 28 and 56 after timed AI, and respectively more anestrous cows conceived.

On the other hand, it has been also reported that the pregnancy rates of cows treated with Ovsynch plus PRID were 11% higher than those of cows treated with Ovsynch alone but without significant differences (Walsh et al 2007). However, Martinez et al (2002) also reported that the addition of progestin resulted in significantly improved pregnancy rates in heifers but not in cows.

El-Zarkouny et al (2004) reported that anoestrus dairy cow treated with Ovsynch plus CIDR had a higher pregnancy rate than anestrous cows treated with Ovsynch alone. However, cycling cows receiving Ovsynch plus CIDR had a pregnancy rate similar to that of cycling cows receiving Ovsynch alone.

Akhiro et al (2008) indicated that one reason of the higher pregnancy rate in CIDR treated group was probably due to existence of a CL on day 0. Furthermore, the plasma progesterone concentrations in CIDR treated cows remained elevated for 7 days to the time of CIDR removal. Perhaps these elevated progesterone concentrations increased the conception rates (Kawate et al 2004; Sakase 2005).

Conclusion

• The present study reported that the inclusion of CIDR to the Ovsynch protocol increased some reproductive performance compared to no CIDR treated group in Algerian cows (estrus response 80%, pregnancy rate 57.4% and conception rate 71.1% versus 48.6%, 31.4% and 64.7%). Such statistical difference is reported when the cows treated were in anoestrus.
  
  
• From the results, it can be inferred that the Ovsynch plus CIDR protocol improved the conception and the pregnancy rates in cows mainly in anestrous under field conditions and contributed to the economical improvement as compared to the previous protocols without CIDR.
  
  
• In some cases, it is therefore possible to free yourself from heat detection and to inseminate all synchronized animals on the same day.

Acknowledgments

Authors thank Professor Daniel Tainturier, Head of the Department of Reproductive Pathology, ONIRIS, Nantes (France) for his collaboration in the improvement of this manuscript. They would also like to thank the staff of the farm for the facilities provided.

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