Effect of meloxicam treatment during early pregnancy in Holstein heifers

Influence of a Single Dose of Meloxicam Administrated during Canine Estrus on Progesterone Concentration and Fertility-A Clinical Case Study

This case report presents an observation of the influence of meloxicam administration, during the periovulatory phase, on corpora lutea function in the domestic dog (Canis familiaris). A 2 year old female German Shepherd dog, with a level of progesterone suggestive of the periovulatory period (5.97 ng/mL), received a single subcutaneous injection of meloxicam (0.2 mg/kg body weight). In this female, subsequent evaluation to detect the optimal time for mating revealed a strong decrease in P4 (2.77 ng/mL), although it increased to 13.98 ng/mL within the following three days. The same female conceived and delivered a litter of the same size as in a subsequent cycle where meloxicam was not administered. The use of NSAID (nonsteroidal anti-inflammatory drugs), and particularly meloxicam, as a COX-2 inhibitor that influences the production of prostaglandins has been reported as being potentially harmful for ovulation and pregnancy in various species, including humans. In dogs, the secretion of prostaglandin E (PGE) is thought to be important for ovulation and the formation of the corpora lutea, the only source of P4, which is required for pregnancy maintenance. Although previous case reports have indicated an influence of meloxicam administration on CL function in domestic dogs, here, the decreased progesterone level observed directly after a single dose of meloxicam was only temporary, with no negative impact on fertility. Based on our observations, further studies related to the influence of the timing of meloxicam administration on ovarian cycle advancement, as well as the influence of duration of treatment, dosage, and route of administration on progesterone levels, as an indicator of CL function, are required.

A Critical Overview on Prostaglandin Inhibitors and Their Influence on Pregnancy Results after Insemination and Embryo Transfer in Cows

Simple Summary

Assisted reproductive techniques, such as artificial insemination or embryo transfer have been used in cattle reproduction for decades, but despite many methodological improvements, pregnancy rates have not increased proportionately. One strategy to improve the pregnancy rate after artificial insemination and embryo transfer is to increase the chance of early embryo survival with the use of medications such as nonsteroidal anti-inflammatory drugs. This paper compares the effect of the application of the most frequently used nonsteroidal anti-inflammatory drugs in cattle (flunixin meglumine, carprofen, meloxicam, ibuprofen, aspirin, and sildenafil), as well as of steroid drugs that are used less frequently in cattle reproduction. An evaluation of published reports revealed a range of outcomes that were not always consistent with each other. However, a positive effect of nonsteroidal anti-inflammatory drug treatment on the pregnancy rate in cattle was indicated, especially with the use of flunixin meglumine.

Abstract

Assisted reproductive techniques in cattle, such as artificial insemination (AI) and embryo transfer (ET), are widely used. Despite many years of methodological improvements, the pregnancy rate (PR) in cows has not increased in direct proportion with their development. Among the possibilities to increase the PR is the use of certain steroids and nonsteroidal anti-inflammatory drugs (NSAIDs). The antiluteolytic effect of NSAIDs is achieved by blocking cyclooxygenase, which is involved in the conversion of arachidonic acid to prostaglandins. This article compares the PRs obtained after treatment with the commonly used NSAIDs in cattle, including flunixin meglumine, carprofen, meloxicam, ibuprofen, aspirin, and sildenafil. Studies on the effectiveness of certain steroid drugs on the PR have also been described. The results were not always consistent, and so comparisons between studies were made. In conclusion, flunixin meglumine seems to be an option, and can be recommended for improving ET results, especially in situations of high exposure or susceptibility to stress. Its administration under all circumstances, however, might be pointless and will not lead to the desired effect.

Effect of flunixin meglumine treatment during and after embryo transfer on the pregnancy rate in cattle

This study aimed to determine the effect of flunixin meglumine treatment during and after the transfer of in vivo produced embryos to Angus (cows) and Holstein (cows and heifers) breeds of cattle on pregnancy rate. Holstein cows were used as donors in the study. A double dose of prostaglandin F2α was administered to the recipient animals for synchronization. Uterine flushing was performed in donors on day 7 after artificial insemination. A total of 295 transferable embryos were obtained. These embryos were transferred to Angus cows (n = 85), Holstein heifers (n = 80) and Holstein cows (n = 130). After the transfer, these animals were divided into three subgroups. The first subgroup (TI) was administered flunixin meglumine during embryo transfer, and the second subgroup (TII) was administered flunixin meglumine both during embryo transfer and on days 8 and 9 after the transfer. The third subgroup (TIII) was not administered anything and it was considered the control group. Pregnancy examination of the recipients was performed on days 30-35 after the transfer using real-time ultrasonography. The pregnancy rates after embryo transfer were found to be 43.52% in Angus cows, 42.5% in Holstein heifers, and 24.61% in Holstein cows (p < .05). When the animals were not classified according to breed, the pregnancy rates in subgroups TI, TII and TIII were found to be 29.29%, 45.10% and 29.79%, respectively (p < .05). In addition, the pregnancy rates were higher in TII and TIII subgroups of Angus cows and Holstein heifers compared to that of Holstein cows (p < .05). As a result, the pregnancy rates obtained after embryo transfer in Angus cows and Holstein heifers were found to be higher than that in Holstein cows. In addition, it was concluded that the administration of flunixin meglumine during and during/after embryo transfer has a positive effect on pregnancy rates in Angus cows and Holstein heifers.

In vitro effects of lipopolysaccharides on bovine uterine contractility

Metritis is an important disorder in dairy cows during the early postpartum period. Myometrial contractility is a prerequisite for uterine involution; however, very scanty literature is available about the effect of metritis on this process and endocrine responsiveness. This study was aimed to evaluate the effect of inflammation on uterine contractility in vitro, and the inflammation was induced by incubating myometrial strips with lipopolysaccharides (LPS). Myometrial samples were collected from 17 healthy Holstein Friesian cows during caesarean section. Eight longitudinal strips from each cow were incubated in organ baths with LPS concentrations of 0 (LPS₀ ), 0.1 (LPS_0.1 ), 1 (LPS₁ ) and 10 µg/ml (LPS₁₀ ). Spontaneous contractility and contractility induced by increasing concentrations of oxytocin (10^-10 - 10^-7  mol/L) were recorded during nine 30-min intervals (T1 to T9). The minimum amplitude (minA), maximum amplitude (maxA), mean amplitude (meanA) and area under the curve (AUC) were calculated for each time interval. LPS had an effect (p ≤ .05) on maxA, meanA and AUC. In T1, myometrial strips incubated with LPS_0.1 and LPS₁ had higher (p ≤ .05) maxA, meanA and AUC than the strips incubated with LPS₀ . In T9 without oxytocin, LPS₀ led to higher (p ≤ .05) maxA, meanA and AUC than LPS_0.1 and LPS₁ . In T8 and T9 with oxytocin, LPS₁ had lower (p ≤ .05) maxA, meanA and AUC than the other LPS concentrations. Interestingly, the results show that LPS has a transient positive effect on myometrial contractility in vitro and that this effect is dependent on LPS concentration and duration of incubation.

Endometrial expression of key genes related to fertility in repeat breeder and non-repeat breeder cows

The aim of the present study was to compare the endometrial gene expression of epidermal growth factor receptor (EGFR), nodal growth differentiation factor (NODAL), prostaglandin-endoperoxide synthase 2 (PTGS2), oestrogen receptor 1 (ESR1) and progesterone receptor (PGR) in repeat breeder cows (RBC) and non-RBC during diestrus. Endometrial samples were collected by cytobrush technique and stored in RNA stabilizing solution at -20°C until RT-qPCR analysis. Differences in endometrial mRNA expression of selected genes were assessed by ANOVA and simple (r) and the partial correlations (rp) among selected genes were performed. Results demonstrated that mRNA expression of EGFR and NODAL were higher in RBC than in non-RBC (3 and 25-fold change, p < .01 and p < .01, respectively), while the mRNA expression of PTGS2 was lower (1.56-fold change, p < .01). Although there were no differences detected in the mRNA expression of ESR1 and PGR, there was a positive correlation between the expression of ESR1 and EGFR (0.84, p < .05) and a negative correlation between PGR and PTGS2 (-0.49, p < .05). In conclusion, the difference on the endometrial mRNA expression of the genes included in the study between RBC and non-RBC indicates a deregulation of important mechanisms that are vital to establish a successful pregnancy. Thus, the present study provides useful insight as a base for future studies to elucidate the causes of RBC.

Early career achievement award: supplementing omega-6 fatty acids to enhance early embryonic development and pregnancy establishment in Bos indicus and B. taurus beef cows

Our research group investigated the impacts of supplementing Ca salts of soybean oil (CSSO), a source of omega-6 fatty acids (FAs), on reproductive performance of beef cows. Initial studies were conducted with Nelore (Bos indicus) cows grazing tropical pastures. Cows were assigned to fixed-time artificial insemination (AI) and supplemented or not with 100 g/d (as-fed basis) of CSSO, and supplementation regimens ranged from days -11 to 28 relative to AI. Overall, CSSO supplementation during the 21 d after AI increased (P < 0.01) pregnancy rates from 38.1% (623/1,635 as pregnant/total nonsupplemented cows) to 49.0% (843/1,720 as pregnant/total CSSO-supplemented cows), and these outcomes were associated with enhanced early embryonic development and pregnancy establishment when omega-6 FA were supplemented. To verify this rationale, our group compared FA incorporation in grazing Nelore cows (n = 90) supplemented or not with CSSO (100 g/d; as-fed basis) beginning at fixed-time AI until slaughter at day 19 of gestation. Supplementing CSSO increased (P ≤ 0.05) incorporation of linoleic acid and its omega-6 derivatives in plasma, endometrium, corpus luteum, and conceptus, whereas the same responses were not observed (P ≥ 0.25) for omega-3 FA. Complementing these findings, grazing Nelore cows (n = 100) were supplemented or not with CSSO (100 g/d; as-fed basis) beginning at fixed-time AI, and assigned to transcervical uterine flush on day 15 of gestation. Supplementing CSSO increased (P ≤ 0.04) conceptus length (2.58 vs. 1.15 cm) and mRNA expression of interferon-tau (4.1-fold increase) and prostaglandin E synthase 2 (2.6-fold increase), which are critical regulators of pregnancy establishment. These outcomes were recently replicated in B. taurus beef cows consuming temperate forages. Pregnancy rates were greater (P = 0.01) in Angus cows receiving CSSO (100 g/d; as-fed basis) for 21 d after fixed-time AI (60.2%; 226/383 as pregnant/total cows) compared with nonsupplemented cows (51.7%; 193/388 as pregnant/total cows). Supplementing CSSO to Angus × Hereford cows (n = 96) beginning after AI also increased (P = 0.05) mRNA expression of interferon-tau in day 15 conceptuses (1.8-fold increase). Collectively, our research demonstrated that post-AI CSSO supplementation favors incorporation of omega-6 FA into maternal and embryonic tissues, which enhances interferon-tau synthesis by the conceptus and increases pregnancy rates to fixed-time AI in B. indicus and B. taurus beef cows.

Supplementing Ca salts of soybean oil after artificial insemination increases pregnancy success in Bos taurus beef cows

Two experiments investigated the effects of supplementing Ca salts of soybean oil (CSSO) during early gestation on reproductive function and pregnancy rates to AI in Bos taurus beef cows. In Exp. 1, 771 suckled, lactating, multiparous Angus cows were divided into 22 groups of approximately 35 cows per group and timed inseminated on day 0. After AI, groups were assigned randomly to receive (as-fed basis) 100 g of ground corn + 100 g of soybean meal per cow/d, in addition to 1) 100 g/cow daily of CSSO (n = 11) or 2) 87 g of prilled saturated fat + 13 g of limestone per cow/d (CON; n = 11). Groups were maintained in individual tall fescue-dominated pastures and offered treatments from day 0 to 21. Pregnancy status was determined between days 45 and 55 via transrectal ultrasonography. Cows receiving CSSO had greater (P = 0.01) pregnancy rates to timed AI compared with CON (60.2 vs. 51.7%; SEM = 4.2). In Exp. 2, 90 suckled, lactating, multiparous Angus × Hereford cows housed in 18 drylot pens (5 cows per pen) were assigned to the same timed AI program and treatments from Exp. 1 (9 pens per treatment) and received 20 kg/d (DM basis) of grass-alfalfa hay. Transrectal ultrasonography was performed to verify ovulation and corpus luteum (CL) volume before AI (day 0), on days 7 and 15. After ultrasonography on day 15, cows diagnosed without a CL on day 0, but with a CL greater than 0.38 cm3 in volume on days 7 and 15 (2 or 3 cows per pen; CSSO, n = 20; CON, n = 24), were assigned to conceptus collection via transcervical flushing and endometrial biopsy in the uterine horn ipsilateral to the CL. Blood samples were collected for FA analysis on days 0, 7, and 15. Blood was collected from cows not assigned to conceptus collection for whole-blood RNA extraction on day 20 and for pregnancy diagnosis on day 30 by measuring concentrations of pregnancy-associated glycoproteins. Cows receiving CSSO had greater (P ≤ 0.04) mean plasma concentrations of linoleic acid and ω-6 FA compared with CON on days 7 and 15. Moreover, CSSO supplementation increased (P = 0.05) mRNA expression of interferon-tau by the conceptus and blood mRNA expression of interferon-stimulated gene 15 and 20,50-oligoadenylate synthetase on day 20 in gestating cows. Hence, post-AI CSSO supplementation to B. taurus beef cows improved pregnancy rates to timed AI, which can be associated with increased mRNA expression of interferon-tau by the conceptus when CSSO is supplemented during early gestation.

Conceptus elongation in ruminants: roles of progesterone, prostaglandin, interferon tau and cortisol

The majority of pregnancy loss in ruminants occurs during the first three weeks after conception, particularly during the period of conceptus elongation that occurs prior to pregnancy recognition and implantation. This review integrates established and new information on the biological role of ovarian progesterone (P4), prostaglandins (PGs), interferon tau (IFNT) and cortisol in endometrial function and conceptus elongation. Progesterone is secreted by the ovarian corpus luteum (CL) and is the unequivocal hormone of pregnancy. Prostaglandins (PGs) and cortisol are produced by both the epithelial cells of the endometrium and the trophectoderm of the elongating conceptus. In contrast, IFNT is produced solely by the conceptus trophectoderm and is the maternal recognition of pregnancy signal that inhibits production of luteolytic pulses of PGF_2α by the endometrium to maintain the CL and thus production of P4. Available results in sheep support the idea that the individual, interactive, and coordinated actions of P4, PGs, IFNT and cortisol regulate conceptus elongation and implantation by controlling expression of genes in the endometrium and/or trophectoderm. An increased knowledge of conceptus-endometrial interactions during early pregnancy in ruminants is necessary to understand and elucidate the causes of infertility and recurrent early pregnancy loss and provide new strategies to improve fertility and thus reproductive efficiency.