Non-steroidal anti-inflammatory drugs at embryo transfer on pregnancy rates in cows: A meta-analysis

Effect of strategies to increase progesterone levels on fertility of bovine embryo transfer recipients - A meta-analysis

The pregnancy rate following embryo transfer (ET) is a very important factor in the success of embryo production programs. Different strategies were therefore developed to increase pregnancy rates. The aim of this meta-analysis was to investigate the effects of hormone treatments used to increase the success of embryo transfer programs on pregnancy rates. A meta-analysis was performed of 46 trials from 39 publications involving treated (n = 7856) and control (n = 6663) cattle. The meta-analysis explained the effect size with its 95 % confidence interval (CI) for pregnancy per embryo transfer (P/ET) after hormonal treatment under different moderators. Hormonal support was found to increase P/ET compared to the control group (P < 0.05). However, GnRH treatment was found to increase P/ET by approximately 4.3 % and hCG treatment by 8.0 %. Progesterone supplementation was not found to have a statistically significant effect on P/ET. In addition, GnRH treatment significantly increased P/ET when used to transfer in vitro or frozen-thawed embryos or in studies using cows as recipients. It was observed that hCG treatment had a positive effect on P/ET according to all moderators. Progesterone supplementation significantly increased P/ET when frozen embryos were transferred and reduced P/ET, especially in publications where fresh or in vitro produced embryos were transferred or cows were used as recipients. The results of this meta-analysis showed that the use of GnRH, and hCG, in bovine embryo transfer programs increased P/ET, whereas the use of progesterone had no effect on P/ET. However, it was found that P/ET could increase/decrease depending on the moderator.

Seasonal distribution of repeat breeder cows and evaluation of modified protocols for post AI treatment during summer

An important problem of dairy industry worldwide is repeat breeder cows (RB). In this study, one farm in Northern Greece was chosen on the basis of subfertility. First, the available reproductive data of the previous year were evaluated; then, the farmer was advised to use the most common treatments for RB [GnRH with the third artificial insemination (AI+GnRH) or ovsynch in cows found empty after the second AI], and their efficacy was monitored throughout the year. Cows (n = 147) 2.5 to 4.5 years old were included. During the next year, post AI treatments (meta-ovsynch and meta-AI) were used during summer; GnRH (100 μg of gonadorelin) alone or in combination with meloxicam (0.5 mg/kg BW) was used during summer. Meta-ovsynch protocols were administered to 29 cows detected as non-pregnant after 3 AIs; cows were divided randomly into 3 meta-ovsynch (OS) groups: group OS (controls, n = 10), standard ovsynch protocol; group OS+GnRH (n = 10), OS plus GnRH 10 days after AI; and group OS+GnRH+NSAID (n = 9), OS plus GnRH 10 days after AI plus meloxicam 15 days after AI. Meta-AI protocols were tested in 27 RB cows; cows were divided randomly into 3 AI groups: GnRH (n = 9), 1 dose of GnRH with AI; GnRH-GnRH (n = 9), two doses of GnRH, one with AI and another 10 days later; and GnRH-GnRH-NSAID (n = 9), two doses of GnRH as in GnRH-GnRH group and one dose of meloxicam 15 days after AI. Pregnancy diagnosis was performed by ultrasound 38 days after AI. During the 1st year of evaluation, 53.79% of cows had received ≥ 3 AIs; the highest percentage (38.48%) of RB cows was recorded during autumn. After treatment for RB, the lowest (P < 0.05) pregnancy rate (PR) was recorded in August (18.18%) compared to January (75.0%), May (53.33%), and December (50.0%, P < 0.1). The efficacy of ovsynch during winter was significantly higher compared to all the other seasons. The percentage of cows with increased estrous cycle duration (24-37 days) after RB treatment and AI was the highest (P < 0.05) in spring and summer after AI+GnRH and the lowest (P < 0.05) during winter after ovsynch. Concerning the post AI treatments during summer, significantly higher pregnancy rate was recorded in the OS+GnRH+NSAID group (55.55%) compared to OS+GnRH (10%) and OS (10%) groups. Pregnancy rates did not differ among AI groups. It seems that OS+GnRH+NSAID is a promising protocol for RB cows during summer although further research is needed to support the present results.

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.