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1.
The objective of the study was to evaluate the interval from onset of oestrus to time of artificial insemination (AI) to obtain the optimum pregnancy rate with sex-sorted semen in Holstein heifers. Heifers in oestrus were detected and inseminated only by using heat–rumination neck collar comprised electronic identification tag at the age of 13–14 months. Heifers (n = 283) were randomly assigned to one of three groups according to the timing of insemination at 12–16 hr (G1, n = 97), at 16.1–20 hr (G2, n = 94) and at 20.1–24 hr (G3, n = 92) after reaching the activity threshold. The mean duration of oestrus was 18.6 ± 0.1 hr, and mean peak activity was found at 7.5 ± 0.1 hr after activity threshold. The mean interval from activity threshold to ovulation was 29.4 ± 0.4 hr. The overall pregnancy per AI (P/AI) was 53.0% at 29–35 days and 50.9% at 60–66 days after AI. There was a significant reduction between G1 (13.8 ± 1.4 hr) and G3 (7.9 ± 1.4 hr) related to the intervals from AI to ovulation time. Sex-sorted semen resulted in significantly higher P/AI at 29–35 days when heifers inseminated in G3 (60.9%) after oestrus than those inseminated in G1 (49.5%) and G2 (48.9%). In terms of fertility, when the temperature–humidity index (THI) was below the threshold value (THI ≤65) at the time of AI, there was a tendency (≤65; 57.2% vs. > 65; 47.1%) for high pregnancy rate. There was no effect of sire on P/AI. In addition, the interaction of the technician with the time of AI was found significant, and three-way interaction of technician, sire and time of AI was tended to be significant on pregnancy rate. Thus, in addition to delaying the time of insemination (between 20.1 and 24 hr) after oestrous detection, THI and experienced technician were also found to be critical factors in increasing fertility with the use of sex-sorted semen in Holstein heifers.  相似文献   

2.
The objective was to compare pregnancy per artificial insemination (P/AI) with conventional (CS) or sex‐sorted semen (SS) in dairy cows subjected to one of the three timed AI protocols. Cows (n = 356) were randomly assigned to synchronization with Ovsynch (OVS), Presynch–Ovsynch (PO) or Double‐Ovsynch (DO) and inseminated on Day 77 ± 3 postpartum with either frozen‐thawed SS (n = 182) or CS (n = 184) of the same bull. More cows were cyclic at the beginning of breeding Ovsynch increased (p < 0.01) with presynchronization and it was greater for DO than PO (OVS = 78.5%, PO = 85.1%, DO = 95.6%). Overall, P/AI for SS and CS increased with presynchronization (p < 0.05) on Days 31 (OVS = 35.5%, PO = 47.1%, DO = 48.3%) and 62 (OVS = 30.1%, PO = 43.8%, DO = 43.9%). Regardless of synchronization treatments, insemination with SS reduced P/AI (p < 0.02) on Days 31 (38.1% vs. 50.6%) and 62 (34.5% vs. 45.6%) compared with CS. No interaction was observed between synchronization treatment and type of semen for P/AI, although in cows receiving CS, P/AI was numerically greatest for PO (OVS = 42.0%, PO = 59.3%, DO = 49.0%), and in cows receiving SS, it was numerically greatest for those inseminated following DO (OVS = 27.9%, PO = 35.5%, DO = 47.6%). Thus, presynchronization improved P/AI in cows inseminated with sex‐sorted or conventional semen.  相似文献   

3.
This study compared artificial insemination pregnancy rate (AI‐PR) between 14‐day CIDR‐GnRH‐PGF2α‐GnRH and CIDR‐PGF2α‐GnRH synchronization protocol with two fixed AI times (56 or 72 hr after PGF2α). On day 0, heifers (n = 1311) from nine locations assigned body condition score (BCS: 1, emaciated; 9, obese), reproductive tract score (RTS: 1, immature, acyclic; 5, mature, cyclic) and temperament score (0, calm; and 1, excited) and fitted with a controlled internal drug release (CIDR, 1.38 g of progesterone) insert for 14 days. Within herd, heifers were randomly assigned either to no‐GnRH group (n = 635) or to GnRH group (n = 676), and heifers in GnRH group received 100 μg of GnRH (gonadorelin hydrochloride, IM) on day 23. All heifers received 25 mg of PGF2α (dinoprost, IM) on day 30 and oestrous detection aids at the same time. Heifers were observed for oestrus thrice daily until AI. Within GnRH groups, heifers were randomly assigned to either AI‐56 or AI‐72 groups. Heifers in AI‐56 group (n = 667) were inseminated at 56 hr (day 32 PM), and heifers in AI‐72 group (n = 644) were inseminated at 72 hr (day 33 AM) after PGF2α administration. All heifers were given 100 μg of GnRH concurrently at the time AI. Controlling for BCS (p < .05), RTS (p < .05), oestrous expression (p < .001), temperament (p < .001) and GnRH treatment by time of insemination (p < .001), the AI‐PR differed between GnRH treatment [GnRH (Yes – 60.9% (412/676) vs. No – 55.1% (350/635); p < .05)] and insemination time [AI‐56 – 54.6% (364/667) vs. AI‐72 – 61.8% (398/644); (p < .01)] groups. The GnRH treatment by AI time interaction influenced AI‐PR (GnRH56 – 61.0% (208/341); GnRH72 – 60.9% (204/335); No‐GnRH56 – 47.9% (156/326); No‐GnRH72 – 62.8% (194/309); p < .001). In conclusion, 14‐day CIDR synchronization protocol for FTAI required inclusion of GnRH on day 23 if inseminations were to be performed at 56 hr after PGF2α in order to achieve greater AI‐PR.  相似文献   

4.
The aim of this study was to compare pregnancy per artificial insemination (P/AI) after timed AI with sex‐sorted sperm (SS) or conventional semen (CS) in lactating dairy cows. Cyclic cows (n = 302) were synchronized by Ovsynch and randomly assigned into two groups at the time of AI. Cows with a follicle size between 12 and 18 mm and clear vaginal discharge at the time of AI were inseminated with either frozen‐thawed SS (n = 148) or CS (n = 154) of the same bull. A shallow uterine insemination was performed into the uterine horn ipsilateral to the side of probable impending ovulation. Pregnancy per AI on Day 31 tended (p = 0.09) to be less for SS (31.8%) than CS (40.9%). Similarly, P/AI on Day 62 was less (p = 0.01) for cows inseminated with SS (25.7%) compared with CS (39.0%). The increased difference in fertility between treatments from Days 31 to 62 was caused by the greater (p = 0.02) pregnancy loss for cows receiving SS (19.2%) than CS (4.8%). Cow parity (p = 0.02) and season (p < 0.01) when AI was performed were additional factors affecting fertility. Primiparous cows had greater P/AI than multiparous cows both on Day 31 (41.7% vs 25.0% in SS and 53.0% vs 31.8% in CS groups) and on Day 62 (33.3% vs 20.5% in SS and 48.5% vs 31.8% in CS groups). During the hot season of the year, P/AI on Day 31 was reduced (p = 0.01) in the SS group (19.6%) when compared with the rates during the cool season (38.1%). In conclusion, sex‐sorted sperm produced lower fertility results compared to conventional semen even after using some selection criteria to select most fertile cows.  相似文献   

5.
This study assessed the efficiency of synchronous oestrous induction by light programme followed by two doses of cloprostenol in acyclic Saanen goats of different parity orders. Primiparous (n = 22) and multiparous (n = 33) goats were subjected to 16 hr of light and 8 hr of darkness for 60 days (D0-D60), starting 10 days after the winter solstice. All goats received 120 µg cloprostenol doses on D130 (morning) and D141.5 (afternoon) (11.5 days apart). Oestrus behaviour, ovarian follicular dynamics and serum progesterone (P4) analyses were recorded from D0 to D174 at different intervals. Animals in oestrus after D141.5 were randomly assigned into two groups: assisted natural mating (NM) or artificial insemination (AI; 10–24 hr after oestrus onset with frozen-thawed semen). From D57 to D120, 89.0% of goats presented large follicles (5–8 mm) and P4 concentrations were subluteal from D0 to D120. More multiparous compared to primiparous goats (54.5%, 18/33 vs. 18.2%, 4/22) exhibited oestrus after both injections. More primiparous compared to multiparous goats (54.5%, 12/22 vs. 12.1%, 4/33) did not exhibit oestrus after any injection. A total of 35 goats (64%) were in oestrus after the second prostaglandin injection and were subjected to NM or AI. The conception rate was similar among primiparous (70.0%, 7/10) and multiparous (68.0%, 17/25) goats but the pregnancy rate differed, being 31.8% (7/22) and 51.5% (17/33), respectively. No interaction was found between parity order and P4 concentrations in does that became pregnant or not. Thus, the association between light programme (60 days, starting at the beginning of winter) and two cloprostenol administrations 11.5 days apart (starting 70 days after the end of the light treatment) resulted in sufficient synchronous oestrous response in multiparous acyclic Saanen goats to reach satisfactory fertility levels after both NM and AI.  相似文献   

6.
The objective of the study was to compare the fertility after using sex-sorted or conventional semen either with oestrus detection (EST) or timed artificial insemination (TAI) in Holstein heifers. Holstein heifers were randomly assigned to one of the following treatments in a 2 × 2 factorial design. Heifers in the EST group were inseminated with sex-sorted (n = 114) or conventional semen (n = 100) after spontaneous or induced oestrus. Heifers in the TAI, subjected to the 5-day Cosynch+Progesterone protocol (GnRH+P4 insertion-5d-PGF2α+P4 removal-1d-PGF2α-2d-GnRH+TAI), were inseminated with sex-sorted (n = 113) or conventional semen (n = 88). Statistical analyses were performed using PROC GLIMMIX procedure of SAS 9.4 (SAS Institute Inc., Cary, NC). Overall P/AI was 60.7% for EST and 54.2% for TAI regardless of types of semen and 68.1% for conventional and 48.9% for sex-sorted semen regardless of insemination strategies. Fertility of heifers inseminated with either sex-sorted (53.5%; 44.2%) or conventional (69.0%; 67.0%) semen did not differ between EST and TAI respectively. Besides, the interaction between the semen type and the insemination strategy was not significant for P/AI. The embryonic loss was significantly greater with sex-sorted semen (17.1%) compared to conventional semen (1.6%). There was no sire effect with sex-sorted semen on P/AI (52.6% vs. 46.2%) and embryonic loss (16.4% vs. 18.0%). As expected, sex-sorted semen resulted in more female calves (89.8% vs. 51.6%) than conventional semen. Thus, sex-sorted semen can be used with 5-day Cosynch+Progesterone protocol to eliminate the inadequate oestrus detection and to increase female calves born in dairy heifers.  相似文献   

7.
The aim of this study was to evaluate the peak in luteinizing hormone (LH) and the pregnancy rate of sheep (Texel × Santa Inês) in the tropics using short‐ (6 days) and long‐term (12 days) progesterone protocols followed by artificial insemination (AI) both in and out of the breeding season. Experiment 1 was conducted within (IN) the breeding season (autumn, n = 36), and experiment 2 was conducted outside (OUT) of the breeding season (spring, n = 43). In each experiment, the sheep were divided into two groups (6 or 12 days) according to the duration of treatment with a single‐use progesterone release vaginal device (CIDR®, Pfizer, São Paulo, SP, Brazil), and blood samples were collected from 10 animals per group every 4 hr to measure the LH and progesterone concentrations. In the spring, the characteristics of the LH peak did not differ between groups; but in the autumn, there were differences between groups at the beginning (G‐6 IN: 36.44 ± 5.46 hr; G‐12 IN: 26.57 ± 4.99 hr) and end of the LH peak (G‐6 IN: 46.22 ± 7.51 hr; G‐12 IN: 34.86 ± 8.86 hr). The results showed alterations in the LH peak during the breeding season only in the sheep undergoing the short‐term protocol.  相似文献   

8.
The study aimed to evaluate pregnancy per artificial insemination (P/AI) of cows subjected to synchronization and resynchronization in ovulation protocols using intravaginal progesterone‐releasing insert (P4) before pregnancy diagnosis (PD) and the relationship of PR with the diameter of preovulatory follicles (ØPOF) before TAI. Cows (n = 378) were distributed into two groups: a resynchronization group with new devices (GRN; n = 185) and resynchronization group with used devices (GRU; n = 193). On Day 0, both groups received a new P4 and estradiol benzoate (EB). On D8, P4 removal + D‐cloprostenol + eCG + estradiol cypionate (EC) was done. On d10, TAI was conducted. On d32, cows were resynchronized and divided into two groups, GRN (n = 185) and GRU (n = 193). The GRN group received a new P4 + EB, and the GRU group received a used P4 + EB. On d40, the P4 was removed + PD. The non‐pregnant cows received D‐cloprostenol + eCG + EC. US was done again on d42 to determine ØPOF before the second TAI. The P/AI of the GRN and GRU groups after synchronization were 56.2% and 57.0% (p = 0.87), respectively, and those after resynchronization were 58.0% and 37.3% (p < 0.008), respectively. The P/AI of the GRN and GRU groups observed after TAI (synchronization + resynchronization) were 81.6% and 73.1%, respectively (p = 0.047). No difference (p = 0.067) in ØPOF between the pregnant and non‐pregnant cows in the GRN was found, whereas the GRU group showed a significant difference (p = 0.003). Resynchronization protocols optimized the P/AI in both groups. New intravaginal devices resulted in greater P/AI and P/AI accumulation in resynchronization as compared with the GRU; the ØPOF was related with P/AI.  相似文献   

9.
The main objective was to investigate the effects of timed-AI protocols versus AI following oestrus detection on circulating progesterone (P4) and embryo survival after first service in Holstein cows. Cycling status was determined by ultrasonography and by plasma P4 concentrations 14 and 26 days after calving, and only cows with a corpus luteum and/or P4 ≥ 1 ng/ml were used. Cows were randomly allocated to one of three types of breeding: DO (n = 80), received GnRH-7d-PGF2α-3d-GnRH and Ovsynch56 was initiated 7 days later; G7G (n = 70), received PGF2α-2d-GnRH and Ovsynch56 (GnRH-7d-PGF2α-56h-GnRH-16h-AI) was initiated 7 days later; or AI based on oestrus detection, EDAI (n = 60). Progesterone was also determined at AI and 8, 16, 18 and 20 days after AI; ISG15 and MX2 mRNA abundance were determined 16 days after AI. Mean plasma P4 at AI was greater in the EDAI group compared with DO and G7G groups, while after AI, P4 was greater in DO and G7G groups compared with EDAI group. However, the percentage of cows with a concentration of P4 < 0.8 ng/ml at AI did not differ among groups. Relative mRNA abundance of ISG15 and MX2 was greater in the DO and G7G groups compared to those in EDAI group. Pregnancy per AI 16, 32 and 60 days after AI was greater (p < .05) in cows in the DO group compared with those in EDAI group (47.5%, 38.8% and 36.3% vs. 30.0%, 21.7% and 15.0%). Pregnancy losses between 16 and 60 days after AI were greater (p < .05) in cows in the EDAI (50.0%) group compared to those subjected to DO (23.7%) or G7G (24.1%). In conclusion, the use of timed-AI synchronization protocols resulted in greater circulating P4 concentrations post-AI and greater embryo survival following first service in lactating Holstein cows.  相似文献   

10.
To assess the effect of the angiotensin‐converting enzyme (ACE) inhibition on the efficiency of the fixed‐time artificial insemination (TAI), 69 goats were divided randomly into two groups: enalapril (n = 35) and control (n = 34). In the experiment, all animals underwent the protocol of fixed‐time artificial insemination for 12 days. Enalapril group received enalapril maleate dissolved in saline (Enalapril, Lab Teuto Ltda) subcutaneously at the following doses: 0.2 mg/kg/day in D0‐D2; 0.3 mg/kg/day in D3‐D6 and 0.4 mg/kg/day in D7‐D11. The control group received the corresponding volume of 0.9% saline solution. We performed a single insemination 36 hr after sponge removal using frozen semen from two adult male goats with recognized fertility. The ultrasound pregnancy diagnosis was 30 days after the artificial insemination (AI). There was significant increase in pregnancy rates and twinning as well as a decrease in foetal loss in animals receiving enalapril (p < .01). The use of ACE inhibitors during the TAI protocol was shown to be a promising alternative to increase the efficiency of such reproductive biotechnology.  相似文献   

11.
The aim of this study was to investigate the expression of progesterone receptor (PR) in the utero‐tubal junction (UTJ) of sows at 24 h after intra‐uterine insemination (IUI) and deep intra‐uterine insemination (DIUI) compared with conventional artificial insemination (AI) in pigs. Fifteen multiparous sows were used: AI (n = 5), IUI (n = 5) and DIUI (n = 5). The sows were inseminated with a single dose of diluted semen during the second oestrus after weaning at 6–8 h prior to ovulation (AI: 3000 × 106 spermatozoa, IUI: 1000 × 106 spermatozoa and DIUI: 150 × 106 spermatozoa). The UTJ was collected and subject to immunohistochemical staining using avidin‐biotin immunoperoxidase technique with mouse monoclonal antibody to PR. In the oviductal part of the UTJ, the intensity of PR in the tunica muscularis and the proportion of PR‐positive cells in the surface epithelium after DIUI were lower than AI (p < 0.05). The intensity and the proportion of PR‐positive cells between AI and IUI in all compartments of the UTJ did not differ significantly (p > 0.05). When comparing between tissue compartments, prominent staining was observed in the muscular layer of the UTJ. It could be concluded that the expression of PR in the UTJ prior to fertilization after DIUI with a reduced number of spermatozoa was lower than that after AI. This might influence sperm transportation and the fertilization process.  相似文献   

12.
Timed artificial insemination (TAI) has boosted the use of conventional artificial insemination (CAI) by employing hormonal protocols to synchronize oestrus and ovulation. This study aimed to evaluate the efficiency of a hormonal protocol for TAI in mares, based on a combination of progesterone releasing intravaginal device (PRID), prostaglandin (PGF2α) and human chorionic gonadotropin (hCG); and compare financial costs between CAI and TAI. Twenty-one mares were divided into two groups: CAI group (CAIG; n = 6 mares; 17 oestrous cycles) and TAI group (TAIG; n = 15 mares; 15 oestrous cycles). The CAIG was subjected to CAI, involving follicular dynamics and uterine oedema monitoring with ultrasound examinations (US), and administration of hCG (1,600 IU) when the dominant follicle (DF) diameter's ≥35 mm + uterine oedema + cervix opening. The AI was performed with fresh semen (500 × 106 cells), and embryo was recovered on day 8 (D8) after ovulation. In TAI, mares received 1.9 g PRID on D0. On D10, PRID was removed and 6.71 mg dinoprost tromethamine was administered. Ovulation was induced on D14 (1,600 IU of hCG) regardless of the DF diameter's, and AI was performed with fresh semen (500 × 106 cells). On D30 after AI, pregnancy was confirmed by US. The pregnancy rate was 80.0% in TAIG and 82.3% in CAIG (p > .05). The TAI protocol resulted in 65% reduction in professional transport costs, and 40% reduction in material costs. The TAI was as efficient as CAI, provided reduction in costs and handlings, and is recommended in mares.  相似文献   

13.
The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding.  相似文献   

14.
Fixed‐time post‐cervical artificial insemination (FTAI) drastically reduces labour requirements and increases the use of boars with higher genetic merit. This study evaluated the efficiency of eCG administration combined with/without the GnRH agonist buserelin for the induction and synchronization of ovulation in weaned sows submitted to FTAI. The sows were allocated into three groups. In the control group, the first artificial insemination was performed at the onset of oestrus and repeated every 24 hr. In the eCG+GnRH group, sows received 600 IU eCG at weaning and buserelin (10 μg) after 86–89 hr of eCG, and in the GnRH group, sows received only buserelin after 86–89 hr of weaning. The hormone‐treated sows received a single FTAI after 30–33 hr of buserelin application. All the sows were inseminated with homospermic doses (1.5 × 109 sperm cells/50 ml). The interval between weaning and ovulation was shorter (p < .05) in the eCG+GnRH (133.3 hr) and GnRH (135.9 hr) groups than the control (141.5 hr) group. In the eCG+GnRH group, the sows ovulated earlier (p < .05) than those in the GnRH group (44.5 vs. 48.2 hr after buserelin administration). The reproductive performance of GnRH sows was not compromised when only sows exhibiting oestrus at the time of insemination were considered, but lower farrowing rate and smaller litter size were observed in eCG+GnRH sows. The reproductive performance of eCG+GnRH sows was primarily compromised because the insemination was performed outside the optimal time relative to ovulation; therefore, it is advisable to inseminate them before 116–122 hr after weaning.  相似文献   

15.
This study focused on the use of radioimmunoassay of progesterone in milk for the diagnosis of post-partum ovarian cyclicity and accurate detection of oestrus and non-pregnancy in cows in the artificial insemination (AI) programme in Bangladesh. In Investigation 1, milk samples were collected on day 0 (day of AI), day 9–13 and day 21–24 from 444 milking cows of various breeds presented for the first post-partum insemination by 413 farmers living at 182 villages/regions in Mymensingh District from 6 AI centres and sub-centres. Each cow was then examined three times after each AI until it stopped returning to oestrus. Sixty to 90 days after the last AI, the cows were examined per rectum to confirm the pregnancy. Milk progesterone data on day 21–24 contributed to a clear diagnosis with respect to non-pregnancy in 100% cows, indicating a possible use of this progesterone assay for identifying non-pregnant cows in AI programmes. In Investigation 2, milk progesterone was monitored two times in a month with a 10-day interval in 88 cows. The samples were taken between 10 days after calving and the first detected oestrus, followed by two more samples 10 days apart. The proportion of cows accurately detected in oestrus was 30%. Another 30% were stated to be in oestrus when they were not (false positive) and 40% were not detected when they were in oestrus (false negative). The mean intervals between calving and oestrus and between calving luteal activity were 40 to 362 days (median = 120, n = 82) and 34 to 398 (median = 111, n = 64) days, respectively. The body condition scores at calving and at the initiation of luteal activity influenced the interval between calving and luteal activity (p < 0.05). Cows suckled twice daily initiated luteal activity earlier than their counterparts suckled several times daily (p < 0.05). Determination of progesterone in milk on day 21–24 is a good means for detecting non-pregnant cows.  相似文献   

16.
Laparoscopic artificial insemination technique (LAI) is described to overcome reduced fertility problems in sheep artificial insemination (AI) programmes with frozen semen. Later on, this technology was modified for endangered non-domestic cats to deposit low quality or reduced number of sperm cells hardly obtained by electro-ejaculation into the oviduct. This technique by passes the complex structure of cervix and efficiently transfers the sperm cells to the point of fertilization. In recent years, rabbits are becoming popular transgenic animal models producing various therapeutic and commercial products, as well as being experimental animals for disease models. The worldwide transportation of frozen semen and re-establishment of transgenic lines using AI technology has become a common practice. Therefore, this study was designed to describe a laparoscopic intrauterine insemination technique, which might assist in conceiving the animals with limited number of sperm cells. The female rabbits were laparoscopically (n = 22) or vaginally (n = 13) inseminated with frozen–thawed semen samples containing approximately 10 × 106 motile sperm. The laparoscopic insemination technique provided higher pregnancy rate (45.5%) than vaginal insemination technique (7.7%) (p < .05). In conclusion, the described laparoscopic AI might be a new alternative technique, thus enabling limited or low-quality frozen sperm samples to establish pregnancy in rabbits.  相似文献   

17.
The objectives were to evaluate the reproductive indices and survival analysis of pregnancy outcomes in multiparous repeat breeder Holstein cows (n = 557). The cows were synchronized to ovulate by Ovsynch, new controlled internal drug release device (N‐CIDRsynch), and once‐used CIDR device (U‐CIDRsynch). The pregnancy per AI at 28 days post‐insemination (P/AI 28) in the N‐CIDRsynch group (28.75%) was significantly (COR = 1.49; p = 0.011) greater than that reported in the Ovsynch (23.46%) and U‐CIDRsynch (21.73%) groups. Furthermore, the pregnancy per AI at day 75 post‐insemination (P/AI 75) in the N‐CIDRsynch group was significantly greater than the Ovysync group (COR = 1.35; p = 0.050). The repeat breeder cows received a N‐CIDR device had a significantly higher progesterone level on day 2 and day 4 of CIDR insertion (1.38 and 1.67 ng/ml, respectively) than those received a U‐CIDR device or the control group (p = 0.012 and 0.001, respectively). The Cox regression model recorded significant associations for synchronization protocols, THI at the TAI and season of calving with the hazard of P/AI 28 and P/AI 75 (p = 0.044 and 0.046; 0.001 and 0.005; 0.003 and 0.001, respectively). Multiparous repeat breeder cows (>3) had a lower hazard ratio (HR) of P/AI 28 than that reported in the reference (2nd parity) group (HR = 0.74, p = 0.050). The repeat breeder cows inseminated at 76–80 and >80 temperature‐humidity index (THI) had significantly lower HR of P/AI 28 than those inseminated at the baseline (<70) THI value (HR = 0.73 and 0.30, p = 0.036 and 0.001, respectively). The current results indicate that the use of N‐CIDR synch protocol may achieve satisfactory pregnancy outcomes in repeat breeder cows.  相似文献   

18.
This study aimed to elucidate the effects of repeated pregnant mare serum gonadotropin (PMSG) treatment for oestrous synchronization (ES) on ovarian gene expression and reproductive parameters in Xinong Saanen dairy goats, the dominant breed of dairy goat in China. The experiment was carried out at the Research Station of Northwest A&F University (NWAFU), China (34°16′N, 108°4′E). Forty‐one does were randomly assigned to groups receiving ES treatments thrice every fortnight (3‐PMSG group; n = 19), or ES treatment only once simultaneously with the third ES treatment in the 3‐PMSG group (1‐PMSG group; n = 22) during middle of the breeding season from late July (14 hr light) until late September (12 hr light). ES treatment was performed via intravaginal insertion of a controlled internal drug release (CIDR) device impregnated with 300 mg progesterone (P4), followed by 300 IU PMSG injections 48 hr before CIDR withdrawal. Oestrus was monitored using vasectomized bucks. Ovaries of three goats in oestrus from both groups were harvested for morphological examination and RNA sequencing (RNA‐Seq). Then, all the oestrous goats in the 1‐PMSG (n = 21) and 3‐PMSG (n = 11) groups were artificially inseminated twice. The 3‐PMSG group showed reduced oestrous rate (57.89%), pregnancy rate (31.58%) and litter size (1.17) compared, respectively, with 95.45%, 68.18% and 1.67 for 1‐PMSG group (p < 0.05). However, no differences were found in the ovarian morphology between the 1‐PMSG and 3‐PMSG groups (p > 0.05). RNA‐Seq revealed 114 differentially expressed genes (DEGs) in the ovaries of the 3‐PMSG group, among which GCG, FSTL3, TET3 and AQP3 were deemed novel and promising candidate genes for regulating fertility. The present study indicates that the three‐time PMSG treatment dysregulated several ovarian genes, thereby reducing reproductive performance.  相似文献   

19.
The effects of standard uterine body and hysteroscopic insemination on endometrial health were investigated. For this purpose, 33 mares were assigned to five different protocols: control (no insemination; n = 7), sham AI (sham uterine body insemination; n = 6), sham HysAI (sham hysteroscopic insemination; n = 7), standard AI (standard uterine body insemination, 300 × 106 progressively motile sperms (PMS); n = 7) and HysAI (hysteroscopic insemination, 100 × 106 PMS; n = 6). Sampling included uterine swabbing for microbiological examination, cytology for determination of polymorphonuclear neutrophils (PMNs) in the uterus, and endometrial biopsy collection for histology and characterization of endometrial immune cells on day 18 after ovulation (B1) as well as 8–10 hours (B2, day 20) and 72 hours after insemination (B3, day 23). Microbial contamination increased throughout the experiment in the sham insemination groups. Significant effects (P < .05) over time were detected for PMNs (cytology: sham HysAI, standard AI, and HysAI; histology: standard AI and HysAI), macrophages (immunohistochemistry: standard AI and HysAI) and T cells (immunohistochemistry: standard AI), showing an increase at B2 and a subsequent decrease toward baseline levels at B3. At B2, significant differences (P < .05) existed for PMNs (mean ± SEM) between control (1.3 ± 1.9%) and sham AI (2.2 ± 2.7%) versus standard AI (12.2 ± 4.7%) and for macrophages between control (4.1 ± 3.5%) and sham AI (2.5 ± 1.3%) versus standard AI (25.4 ± 15.8%). Thus, the cellular immune response of the endometrium depends on sperm deposition in the uterus and does not differ between hysteroscopic and standard uterine body insemination.  相似文献   

20.
This study compares the factors associated with variable interval to oestrus and ovulation between early versus late ovulating goats following PGF2α administration. The time of ovulation in Beetal goats (n = 38) was monitored through transrectal ultrasound at every 6 hr following a single dose of PGF2α (experiment 1). Variations in oestrus and ovulation times were further explored through the changes in follicular dynamics, endocrine profiles and behaviour in another set of goats (n = 13) following single PGF2α given randomly during the luteal phase (experiment 2). The ovulation time varied between 60 and 96 hr, and 57% of ovulations occurred by 72 hr following PGF2α (experiment 1). Accordingly, the goats (n = 13) in the second experiment were retrospectively divided either into early and/or late ovulating, that is, ≤72 and/or ≥84 hr following PGF2α. The onset of oestrus, peak estradiol‐17β concentration and LH surge after PGF2α was first observed in early than late ovulating goats (p < 0.05). The goats ovulating early had larger follicle and smaller CL in diameter at the time of PGF2α administration than those ovulating late (5.4 ± 0.2 vs. 4.3 ± 0.2 mm and 10 ± 0.6 vs. 11.8 ± 0.3 mm, respectively; p < 0.05). Likewise, plasma progesterone concentration tended to be lower (p = 0.087) in early than late ovulating goats. In conclusion, the size of dominant follicle and CL at the time of PGF2a determines the interval to ovulation following a single dose of PGF2a during the luteal phase.  相似文献   

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