Ovarian responses of dairy buffalo cows to timed artificial insemination protocol, using new or used progesterone devices, during the breeding season (autumn-winter)

Upgrading the fixed-time artificial insemination (FTAI) protocol in Romanian buffaloes

The present study describes the challenges of assisted reproduction in Romanian buffaloes while increasing the efficacy of artificial insemination by choosing the most suitable method. The modified fixed-time artificial insemination (FTAI) protocol with sexed semen was used to increase the conception rate. This study included a total of 80 buffalo heifers that received ovarian stimulation using the OvSynch protocol. Two groups (n = 40), namely, a control group, in which the classic FTAI method was performed, and an experimental group, in which deep intrauterine AI was performed in cows that had developed a dominant follicle (US+UcFTAI), were randomly selected. The conception rate (CR) was 63.6% in the experimental group, which was statistically higher (P < 0.05) than the control group (30%). The ultrasound examination indicated that, using the OvSynch protocol, 82.5% (33 out of 40) of buffaloes developed a dominant follicle (DF) while the distribution between the warm and cold seasons was 75 and 90%, respectively. The CR was 60% during the hot season and 66.6% during the cold season. At calving, 92.5% female fetuses were born. The improved FTAI method in this study enhanced the results by reducing the waste of sexed semen and maximizing the response to OvSynch, making it a recommendation for practitioners. This study presents preliminary results and highlights that genetic progress is difficult to achieve. A systematic approach is needed in order to choose the most suitable biotechnological method for each farm.

Application of Exogenous GnRH in Food Animal Production

Over several decades, exogenous GnRH and agonists have been employed for controlling reproductive cascades in animals, and treating some reproductive morbidities. The administration of GnRH is used in animals to counter ovarian dysfunction, induce ovulation, and to increase conception and pregnancy rates. GnRH and its agonists are used in the treatment of cystic ovarian degeneration and repeat breeder syndrome. The development of protocols for GnRH administration by intramuscular injection, intramuscular or subcutaneous implants, and intravaginal deposition has empowered their clinical use worldwide. Currently, exogenous GnRH products are a central part of several pre- and post-breeding programs for the enhancement of fertility, including the control of estrous cycles and timing of ovulation, development of fixed-time artificial insemination protocols, improved embryo survival, and the treatment of reproductive morbidity. The aim of the present review is to summarize the application of exogenous GnRH agonists in food animal production.

Influence of Days after Calving and Thermal Stress on the Efficacy of a Progesterone-Based Treatment in Acyclic Italian Mediterranean Buffalo

Simple Summary

“Mozzarella di Bufala Campana DOP” (mozzarella cheese) is mainly produced and marketed during the spring and summer months. The buffalo is a seasonal species that increases its reproductive activity when daylight hours decrease. Therefore, to increase milk production in the favourable period, the so-called “Out of Breeding Season Mating” technique is applied. It consists of the interruption of sexual promiscuity during the naturally occurring breeding season and concentrating calving and milk production during periods of increasing daylight length. However, the application of this technique increases the incidence of anoestrus, as animals are forced to breed outside of their natural and favoured period of the year, although other factors can also increase the incidence of anoestrus, such as climate. A reduction of seasonal anoestrus can be achieved by using some hormonal treatments. In this study, primiparous acyclic buffaloes were selected and divided into three classes according to their days in milk. Animals were synchronized using P₄ vaginal implants, and artificial insemination (AI) was performed according to protocol. The temperature–humidity index (THI) was recorded to evaluate its influence on anoestrus. Statistical analysis showed that the implemented P₄-based treatments were highly effective in removing the anoestrus condition in buffaloes. On the contrary, no influence of the THI on the efficacy of the P₄ synchronization treatment was observed.

Abstract

The aim of this study was to evaluate the efficacy of a progesterone-based treatment on anoestrus in buffaloes. Primiparous acyclic buffaloes (n = 276), were divided into three classes according to their days in milk (DIM): from 50 to 90 (Class I; n = 86), from 91 to 150 (Class II; n = 102) and from 150 to 200 (Class III; n = 88). Animals were synchronized using P₄ vaginal implants, followed by timed artificial insemination (TAI). They were then allowed to enter into a larger group of buffaloes for natural mating 15 days after AI was performed, and pregnancy status was monitored from then on at 15-day intervals. Finally, the temperature–humidity index (THI) was calculated. Statistical analysis was performed by ANOVA by means and both multiple and linear regression. The total pregnancy rate (PR) was 87.7%, with no differences among DIM classes (88.0, 92.4, and 80.0% in Classes I, II, and III, respectively). However, the PR at TAI tended to be higher (p = 0.07) in buffaloes in Class II. The follicle (FL) area in Class II buffaloes was larger (p < 0.01) than that of the other classes. No influence of the THI on the total PR was recorded. The pregnancy outcome at TAI was affected by the FL area (odds ratio = 2.237; p < 0.05) and body condition score (BCS) (odds ratio = 1.256; p < 0.05). In conclusion, treatment with vaginal P₄ optimizes pregnancy rates in anoestrus buffaloes, particularly when the animals are in mid-lactation and show an optimal BCS. Furthermore, the THI does not seem to affect the efficiency of the progesterone treatment.

GPGMH, a New Fixed Timed-AI Synchronization Regimen for Swamp and River Crossbred Buffaloes (Bubalus bubalis)

The crossbreeding of Swamp and River type buffalo breeds is practiced for the improvement of milk yield and reproductive performance in swamp buffalo herds. This study aimed to modify the Ovsynch synchronization protocol (GPG) and improve the fixed-timed artificial insemination (FTAI) for better reproductive performance of crossbred buffaloes. Comparison of four conventional synchronization protocols [pregnant mare gonadotropin-prostaglandin F₂α-gonadotropin-releasing hormone (PmPG), gonadotropin-releasing hormone-prostaglandin F₂α-gonadotropin-releasing hormone (GPG), prostaglandin F₂α-gonadotropin-releasing hormone-prostaglandin F₂α-estradiol benzoate (PGPE), and progesterone-pregnant mare gonadotropin-prostaglandin F₂α-gonadotropin-releasing hormone (P₄PmPG)] in crossbred buffaloes showed that the GPG protocol treated buffaloes displayed higher (P < 0.05) estrus response with an increasing tendency in ovulation (84.6%) and pregnancy rates (30.8%) than PmPG, PGPE, and P₄PmPG treated buffaloes. Buffaloes treated with a dose of 0.4 (mg/kg) mifepristone combined with GPG, exhibited higher (P < 0.05) estrous response (82.4%), ovulation (94.1%), and pregnancy (47.1%) rates compared with other doses (0, 0.3, or 0.5 mg/kg) groups. Injection of mifepristone along second GnRH injection in buffaloes improved (P < 0.05) pregnancy rate (35.3%) when compared to before or after the second GnRH of GPG protocol. Single AI after 24 h of mifepristone or second GnRH injection seems the best time to enhance the pregnancy rates in buffaloes compared to double or other single AI times in the modified GPGMH protocol. In comparison, GPGMH reduced the follicular cyst incidence (P < 0.05) with increasing ovulation (P > 0.05) and pregnancy rates (P > 0.05) than the P₄GPG and GPG protocols in crossbred buffaloes. The current study supported that new synchronization protocol (modified of GPG protocol; GPGMH) by the inclusion of mifepristone (with a dose of 0.4 mg/kg along second GnRH), AI after 24 h of mifepristone or second GnRH, and human chorionic gonadotropin (hCG at day 5 of AI) enhance the ovulation and pregnancy rates in crossbred buffaloes.

Use of cooled buffalo semen as a strategy to increase conception rates in fixed-time artificial insemination programs during unfavorable reproductive periods

ABSTRACT The objective of this study was to compare the reproductive efficiency of dairy buffaloes undergoing fixed-time artificial insemination (FTAI) protocols based on progesterone/estrogen (P4/E2) and eCG during unfavorable breeding season using cooled (CS) and frozen semen (FS). A total of 446 buffaloes (> 40 days postpartum) were randomly distributed into four blocks (years): B1-2014 (n = 143), B2-2015 (n = 34), B3-2016 (n = 90), and B4-2017 (n = 179). Each block was subdivided into two (AI with CS and FS using the same ejaculate of each bull). Thus, the block subdivision was as follows: B1 (CS = 71 and FS = 72); B2 (CS = 18 and FS = 16); B3 (CS = 47 and FS = 43); and B4 (CS = 90 and FS = 89). The ejaculates of eight Murrah bulls collected using an artificial vagina were divided into two aliquots: one aliquot was diluted in Botu-Bov® commercial extender and cooled (BB-CS), and the other was diluted in the same extender and frozen (BB-FS). BB-CS aliquots were cooled at 5 °C/24 h using a refrigerator. BB-FS group aliquots were also cooled, and after equilibrating at 5 °C for 4 h, were placed in a 21-L Styrofoam box, 5 cm above the surface of liquid nitrogen. In the afternoon (A) on D0 (2:00 p.m.) the animals received EB 2.0 mg IM (Estrogin®) and an ear implant (CRESTAR® 3.0 mg P4). At D9 (A), the implant was removed, and the animals received eCG 400 IU IM (Folligon® 5000) + Cloprostenol PGF2α 0.530 mg IM (Sincrocio®). At D10 (A), the animals received EB 1.0 mg IM (Estrogin®), and at D12 (8:00 a.m.), AI was performed. At D42, pregnancy was diagnosed via ultrasonography. Total CRs were 48.2% CS and 34.6% FS for years 2014 to 2017, with a significant difference of 13.7% (P<0.05). In conclusion, cooled semen resulted in higher CR than frozen semen in dairy buffaloes under the P4/E2 and eCG FTAI during the unfavorable reproductive season.

Use of Estradiol Cypionate to induce ovulation in buffalo raised in floodplain areas of Itacoatiara, Amazonas

ABSTRACT This study aimed to determine the efficiency of estradiol cypionate (EC) as an ovulation inducer in a Timed Artificial Insemination protocol. 69 buffalo cows received an intravaginal progesterone device and 2mg of estradiol benzoate (EB) at D0. On D9, the intravaginal device was removed and 0.53mg of prostaglandin (PGF2α) and 400UI of equine chorionic gonadotrophin (eCG) were applied. The cows were distributed into two groups: the first group received 1mg of EC (ECG) in D9, and the second group received 1mg of EB (EBG) in D10. Inseminations occurred on D11. Ovarian activity and pregnancy diagnosis were analyzed by ultrasonography. There was no difference (P>0.05) in follicular diameter (9.6 ± 0.89mm vs. 10.7 ± 1.12mm; P=0.06), in ovulation rate (90.9% vs. 90.9%; P=1) and pregnancy rate (58.8% vs. 62.9%; P=0.79), however, buffalo cows from the ECG treatment have less time between P4 removal and ovulation when compared to EBG buffalos (37.4h vs. 52.8h; P=0.001), respectively. Thus, it was concluded that the implantation of TAI in the floodplain of Amazonas is feasible and the use of EC results in successful rates, similar to EB.

Treatment with estradiol cypionate at progesterone withdrawal reduces handling without compromising the pregnancy rate to timed-AI in buffalo

The aim of this study was to determine if treatment with estradiol cypionate (EC) at the time of P4 withdrawal induced ovulation in a synchronization/timed-AI (TAI) protocol in buffalo. In Experiment 1, 56 buffaloes received an intravaginal P4 device (1.0 g) plus estradiol benzoate (EB, 2.0 mg im) on Day 0 (D0). On Day 9, the P4 device was removed and buffaloes were given PGF_2α (0.53 mg im sodium cloprostenol) plus eCG (400 IU im). Buffaloes were then randomly allocated to one of two groups: Group GEC (n = 29), treated with EC (1.0 mg im) at P4 device removal; Group GEB (n = 27), treated with EB (1.0 mg im) 24 h after P4 device removal. Ovarian ultrasound was undertaken on: D0, to ascertain general ovarian status; D9 to D11 (every 24 h), to measure diameter of the largest follicle (LF) and follicular growth rate; D11 to D13 (every 12 h for 72 h), to determine the time of ovulation and ovulation rate. Following P4 device removal, Groups GEC and GEB had a similar follicular growth rate (0.9 ± 0.1 and 1.1 ± 0.1 mm/day, respectively; P = 0.15) and similar LF diameter on D11 (11.4 ± 0.6 and 12.5 ± 0.5 mm; P = 0.12). Groups GEC and GEB also had a similar diameter of the ovulatory follicle (13.0 ± 0.5 and 13.4 ± 0.6 mm; P = 0.52), interval from P4 device removal to ovulation (68.2 ± 2.8 and 71.1 ± 1.4 h; P = 0.41) and ovulation rate (62.1% and 70.4%; P = 0.44). In Experiment 2, 199 buffaloes were assigned to the two treatments in Experiment 1 (GEC, n = 100; GEB, n = 99). All animals underwent TAI 56 h after P4 device removal and pregnancy diagnosis was preformed on D41. The pregnancy rate was similar for Groups GEC and GEB (50.0 and 45.5%, respectively; P = 0.45). The findings indicate that treatment with EC at the time of P4 withdrawal induces ovulation and achieves the same pregnancy rate to TAI as treatment with EB 24 h after P4 removal. The use of EC requires one less handling which is highly important in facilitating practical adoption of TAI in assisted breeding and genetic improvement in buffalo.

Effect of season on dairy buffalo reproductive performance when using P4/E2/eCG-based fixed-time artificial insemination management

This study aimed to compare the reproductive efficiency of dairy buffaloes subjected to TAI protocols based on progesterone, estrogen, and equine chorionic gonadotrophin (P4/E2+eCG) during the fall/winter (n = 168) and spring/summer (n = 183). Buffaloes received an intravaginal P4 device (1.0 g) plus estradiol benzoate (EB; 2.0 mg im) at a random stage of the estrous cycle (D-12). Nine days later (D-3), the P4 device was removed and buffaloes were given PGF_2α (0.53 mg im sodium cloprostenol) plus eCG (400 IU im). GnRH (10 μg im buserelin acetate) was administered 48 h after P4 device removal (D-1). All animals were subjected to TAI 16 h after GnRH administration (D0). Frozen-thawed semen from one bull was used for all TAI, which were all performed by the same technician. Ultrasound examinations were performed on D-12 and D-3 to ascertain cyclicity (presence of CL), D-3 and D0 to measure the diameter of the dominant follicle (ØDF), D+10 to verify the ovulation rate and diameter of the corpus luteum (ØCL), and D+30 and D+45 to detect pregnancy rate (P/AI 30d and 45d, respectively) and embryonic mortality (EM). Fetal mortality (FM) was established between 45 days and birth, and pregnancy loss between 30 days and birth. There were significant differences between fall/winter and spring/summer only for cyclicity rate [76.2% (128/168) vs. 42.6% (78/183); P = 0.02]. The others variables did not differ between the seasons: ØDF on D-3 (9.6 ± 0.2 mm vs. 9.8 ± 0.2 mm; P = 0.35); ØDF on D0 (13.1 ± 0.2 mm vs. 13.2 ± 0.2 mm; P = 0.47); ovulation rate [86.9% (146/168) vs. 82.9% (152/182); P = 0.19]; ØCL on D+10 (19.0 ± 0.3 mm vs. 18.4 ± 0.3 mm, P = 0.20); P/AI on D+30 [66.7% (112/168) vs. 62.7% (111/177); P = 0.31]; P/AI on D+45 [64.8%% (107/165) vs. 60.2% (106/176); P = 0.37]; EM [1.8% (2/111) vs. 3.6% (4/110); P = 0.95]; FM [21.9% (18/82) vs. 8.0% (7/87); P = 0.13]; and PL [23.8% (20/84) vs. 12.1% (11/91); P = 0.13]. In conclusion, dairy buffaloes present similar reproductive efficiency in fall/winter and spring/summer when subjected to P4/E2/eCG-based protocol for TAI.

Pregnancy rate in water buffalo following fixed-time artificial insemination using new or used intravaginal devices with two progesterone concentrations

This study evaluated the pregnancy rate (PR) after timed artificial insemination (TAI) in water buffalo (Bubalus bubalis) during both non-breeding and breeding season, using either a new or reused intravaginal device (IVD) with two different progesterone concentrations. A total of 247 dairy buffalo cows were randomly assigned using a two-by-three factorial design and four replicates to the following groups: (1) new intravaginal device (IVD-New: DIB®, 1.0 g of P₄, n = 51 or CIDR®, 1.38 g of P₄, n = 55); (2) intravaginal device previously used once (9 days) (IVD-Used1x: DIB, n = 40 or CIDR, n = 51); or (3) intravaginal device previously used twice (18 days) (IVD-Used2x: DIB, n = 27 or CIDR, n = 23). On day 0, animals received the IVD plus 10.5 μg of buserelin acetate (GnRH) intramuscularly. On day 9, the devices were removed and 25 mg of PGF₂α plus 500 IU of eCG was given intramuscularly. On day 11 (48 h after IVD withdrawal), animals received 10.5 μg of GnRH and were artificially inseminated 8-12 h later. Data were analyzed using Proc Logistic of SAS®. Animals that received IVD-New-DIB, had a significantly higher PR (62.7%; P = 0.0193) compared to animals that received IVD-New-CIDR (40%). Pregnancy rate was not negatively affected by reusing both types of IVD. Overall PR (new and reused devices) was higher (P = 0.0055) in the DIB group (62.7%) compared to the CIDR group (45%). In conclusion, PR was higher in buffaloes treated with devices containing 1.0 g of P₄ (DIB®) compared to those receiving 1.38 g of P₄ (CIDR®). Reusing the intravaginal devices did not affect negatively PR/TAI, suggesting that P₄ concentrations within the TAI protocols in water buffaloes could be reduced, without impairing their fertility.

Alginate encapsulation preserves the quality and fertilizing ability of Mediterranean Italian water buffalo (Bubalus bubalis) and Holstein Friesian (Bos taurus) spermatozoa after cryopreservation

The use of artificial insemination (AI) in buffalo (Bubalus bubalis) is limited by poor ovarian activity during the hot season, seasonal qualitative patterns in semen, low resistance of sperm cells in the female tract, difficulties in estrus detection, and variable estrus duration. Although AI procedures are commonly used in bovine, use of AI has been limited in buffalo. In the zootechnical field, different studies have been conducted to develop techniques for improvement of fertilizing ability of buffalo spermatozoa after AI. In this study, for the first time, the use of alginate encapsulation and cryopreservation of buffalo spermatozoa is described, and the same procedure was performed with Holstein Friesian (Bos taurus) semen. Results obtained from in vitro analyses indicate that the encapsulation process does not have detrimental effects (compared to controls) on quality parameters (membrane integrity, progressive motility, path average velocity) in either species. Similarly, there were no detrimental effects after cryopreservation in either species. The fertilizing potential of encapsulated and cryopreserved semen was evaluated after AI in 25 buffalo and 113 bovine females. Pregnancy rates were not affected in either species. The results of this study show proof of concept for the use of frozen semen controlled-release devices in buffalo.