A caudal flank approach for the collection of oviductal-stage bovine embryos

Fetal mummification in the major domestic species: current perspectives on causes and management

Fetal mummification is an uncommon condition in most domestic species. While most often seen in multiparous and polytocous species like swine, it is also observed in monotocous species when the fetus is retained for a long time. The low prevalence of the condition may help explain the scarcity of information in the literature. To further complicate the study of this phenomenon, the physiological mechanisms that maintain pregnancy vary between species, implying different pathways for the condition. The exact outcome of early fetal mortality is unpredictable, and is influenced by several factors, including the cause of fetal mortality, differences in pregnancy between species, stage of gestation at fetal death, and number of fetuses. Based on our current knowledge of natural fetal mummification events, there are a number of prerequisites for the process of fetal mummification to occur. Examining the circumstances associated with fetal mummification can help scientists better understand the etiology and clinical situation in different species. The objective of this article is to review fetal mummification in the major domestic species: cattle, goats, sheep, horses, swine, dogs, and cats. This paper discusses the clinical situation, the most common and important etiologies, and the treatment approaches for restoring future pregnancy in the female, and where applicable, herd fertility.

In vivo culture of IVM/IVF embryos in bovine oviducts by transvaginal endoscopy

This study was conducted to establish a new approach for in vivo culture of in vitro produced embryos in the bovine oviduct by transvaginal endoscopy. Embryos were in vitro matured, fertilized and cultured for 1-4 days and assigned to groups consisting of 10-30 embryos. Embryos were transferred unilaterally into oviducts of 24 heifers by the means of transvaginal endoscopy. After 3-6 days of in vivo incubation embryos were re-collected. Experiment I aimed to evaluate the capability of embryos to migrate to the uterus. The uterine horns of four animals were flushed first, followed by a combined flushing of both oviducts and uterine horns resulting in collection rates of 31 and 34%, respectively. In experiment II, the transfer of embryos into the oviduct close to ovulation (day 1-2--experiment IIA) or at a more advanced cyclic stage (day 3--experiment IIB) succeeded in the collection of 46 and 34% of the transferred complexes, of which 13 and 37% showed the blastocyst stage. This is the first report of successful recovery of transferable blastocysts by transvaginal endoscopy after tubal in vivo culture in the homologous species of originally in vitro produced embryos.

Collection of tubal stage bovine embryos by means of endoscopy. A technique report

Here we describe the development and optimization of endoscopy-mediated transvaginal access for collecting ova and embryos from the bovine oviduct. The novel technique was developed in three experimental setups: In Experiment 1 embryos were collected unilaterally from nonstimulated heifers. We flushed the oviducts of superovulated heifers unilaterally (Experiment 2) and bilaterally (Experiment 3). In Experiment 1 the oviducts of 18 heifers were successfully cannulated, which resulted in the collection of twelve 1-cell to 8-cell embryos and one empty zona. Unilateral flushing of 13 animals (Experiment 2) resulted in 84 ova with 6.3 +/- 3.2 observed ovulation sites. Bilateral flushing of 25 animals (Experiment 3) resulted in 293 ova plus 10 empty zonae from 11.8 +/- 5.4 ovulation sites. Given our experience from these studies we optimized the technical equipment by improving the flushing metal catheter (Experiment 4). The novel catheter hermetically sealed the lumen of the ampulla at the moment, the medium was flushed through the oviduct. This resulted in a visible flow of medium via oviducts toward the embryo filter connected to an embryo flushing catheter that was fixed in the uterine horns. Our endoscopy-guided method is minimally invasive and facilitates the flushing of tubal stage embryos.

Effects of time of deoxyribonucleic acid microinjection on gene detection and in vitro development of bovine embryos

In vivo fertilized embryos were surgically collected from superovulated dairy cows to evaluate microinjection on embryo development and utilized the polymerase chain reaction technique for selection of transgenic embryos. Seventy-two percent of the embryos with visible pronuclei or nuclei were microinjected with DNA, and the remaining 28% served as uninjected controls. All embryos were cocultured with bovine oviductal epithelial cells. Mean final development scores of embryos within the same initial cell stage at collection were unaffected by microinjection. After 144 h of culture, 45% of the microinjected embryos developed to the morula or blastocyst stage. The transgene was detected in 50, 10, and 9% of demimorulae from embryos microinjected at the 1-, 2-, and 4-cell stages. Frequency of transgene detection was higher in morulae from 1-cell embryos than in morulae from 2- and 4-cell embryos. Use of in vitro coculture, embryo bisection, and polymerase chain reaction technique facilitated selection of bovine embryos that carried the transgene.

Female urogenital surgery in cattle

Surgical manipulation of the female reproductive tract is part of routine bovine clinical practice. Most indications for urogenital surgery in cattle are for alleviation of dystocia or correction of injuries sustained during parturition. Less frequently, surgery is indicated for ovarian tumor removal, embryo transfer, or spaying of feeding heifers. This article discusses clinical assessment for selection of various surgical procedures of the bovine female genital tract.

Use of in vitro fertilization for production of calves from involuntary cull cows

PURPOSE

The main purpose of the study was to assess the feasibility of a combined system for in vitro maturation of oocytes, in vitro fertilization, and in vitro culture of embryos for production of calves from cows that have to be removed prematurely from production units.

RESULTS

Eighteen cows that were to be culled from experimental dairy production units were ovariectomized. An average of 45.7 oocytes per cow was collected from the ovaries. After in vitro maturation and fertilization of the oocytes, an average of 40.8 presumptive zygotes was placed into in vitro culture, with an average of 16.1 cleaving by day 2 and an average of 5.7 developing to morulae/blastocysts by day 6 or 7. A greater mean quantity of oocytes was collected from cows that were ovariectomized between day 5 and day 13 of the estrous cycle than from those that were ovariectomized between day 0 and day 3 of the estrous cycle. Correspondingly larger mean numbers of cleaved zygotes and morulae/blastocysts were produced from the cows that were ovariectomized between day 5 and day 13 of the cycle. Transferable embryos were produced from 17 of the 18 cows. Eighteen embryos from six oocyte donor cows were transferred to recipients. Six of the eighteen recipients were confirmed to be pregnant after 40 days. Three of the pregnant recipients delivered live calves at term. Two others remain pregnant but have not reached term. The sixth recipient aborted at approximately 120 days of gestation.

CONCLUSIONS

Results from the preliminary study indicate that this system can be used for production of calves from cull cows. Although transferable embryos were produced from all except one cow, there was a high degree of variability among cows in total number of oocytes recovered and embryos produced. More donors need to be evaluated to determine the effects of age, breed, reason for culling, and source of semen.

Vagino-cornual cannulation and embryo recovery from crossbred (Bos indicusxBos taurus) heifers

Successful vaginal and bicornual cannulations were performed with a tabular cannulator shaped like a giant hypodermic needle in crossbred (Bos indicusxBos taurus) heifers (n=7). A total of 58 embryos from a possible 73 were flushed out. The embryo recovery rate was 79.45% and average recovery time was 50 minutes. The wound healing at cannulation sites was rapid. All heifers except one conceived due to insemination during subsequent cycles. One heifer developed pyometra and did not settle.