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New Strategies to Manage Reproduction in Sheep- Starting with Embryos and Sperm

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Special Issue Editors

Dr. Laura Falchi

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Guest Editor

Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy
Interests: reproduction; fertility; spermatozoa; cryopreservation; artificial insemination; MOET; oocyte; embryo production

Dr. Maria Teresa Zedda

E-Mail Website
Guest Editor

Section of Obstetrics and Ginecology, Department of Veterinary Medicine, University of Sassari, Sassari, Italy
Interests: reproduction, fertility, spermatozoa, cryopreservation, artificial insemination, MOET, oocyte, embryo production

Special Issue Information

Dear colleagues,

The rate of genetic improvement in the sheep breeding industry is limited by the poor uptake of techniques that are almost consolidated for other species. The main obstacles lie behind a “female factor”, the convoluted anatomy of the sheep cervix, and a “male factor”, the poor resistance of ram semen to cryopreservation. The cervical lumen of the sheep does not allow the passage of catheters employed for uterine semen deposition and embryo transfer procedures (i.e., flushing and transfer of embryos). This implies the need to proceed with laparoscopy and surgical approaches. On the male side, frozen thawed ram semen has a short lifespan, being vulnerable to oxidative stress with consequent loss in fertilizing ability.

In recent decades, many strategies have been designed to overcome the limited diffusion of reproductive techniques for the ovine species, but reliable, consistent, and sustainable solutions are still far from being found. Recent developments in artificial insemination, embryo transfer, and semen storage lay the ground for future research in this challenging branch of animal reproduction.

This Special Issue of Animals is open to original research papers that cover current issues in ovine reproduction, with a special focus on novel approaches to improve reproductive efficiency in this species.

Dr. Laura Falchi
Dr. Maria Teresa Zedda
Guest Editors

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Keywords

ovine
artificial insemination
spermatozoa
embryos
MOET
synchronization
LOPU
cervix
fertility
ovulation

Published Papers (2 papers)

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Research

12 pages, 2184 KiB

Open AccessArticle

The Design of a New Catheter for Transcervical Artificial Insemination in Ewes

by Laura Falchi, Maria Teresa Zedda, Salvatore Pau, Mauro Ledda, Valentino Melosu and Salvatore Pier Giacomo Rassu

Animals 2021, 11(12), 3348; https://doi.org/10.3390/ani11123348 - 23 Nov 2021

Cited by 2 | Viewed by 2817

Abstract

In ovine species, transcervical artificial insemination (TCAI) is limited by the poor quality of frozen–thawed semen and by the convoluted cervical lumen hampering the passage of inseminating devices. The aim of the study was to test the efficiency of three newly designed catheters with bent tips of 3.5 mm, 5.0 mm or 8.0 mm in terms of reproductive performances (experiment 1) and to compare the results of TCAI with the best performing catheter of experiment 1 to those obtained in ewes submitted to surgical incision of cervical folds (SICF) prior to insemination (experiment 2). The following parameters were assessed: time to pass the cervix; depth of cervical penetration; site of deposition of semen; pregnancy (PR); and lambing rates (LR). The results of experiment 1 indicated that the 5.0 mm tip catheter resulted in deeper and faster TCAI and higher PR and LR compared to 3.5 mm and 8.0 mm tip catheters (p < 0.05). In experiment 2, TCAI with the 5.0 mm catheter did not differ from TCAI after SICF in terms of depth of semen deposition, time to pass the cervix, PR and LR (p < 0.05). In conclusion, the use of a catheter that allowed transcervical uterine deposition of semen without excessive manipulation led to satisfactory pregnancy rates. Full article

(This article belongs to the Special Issue New Strategies to Manage Reproduction in Sheep- Starting with Embryos and Sperm)

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16 pages, 2052 KiB

Open AccessArticle

Toxic and Microbiological Effects of Iron Oxide and Silver Nanoparticles as Additives on Extended Ram Semen

by Ioannis A. Tsakmakidis, Theodoros Samaras, Sofia Anastasiadou, Athina Basioura, Aikaterini Ntemka, Ilias Michos, Konstantinos Simeonidis, Isidoros Karagiannis, Georgios Tsousis, Mavroeidis Angelakeris and Constantin M. Boscos

Animals 2021, 11(4), 1011; https://doi.org/10.3390/ani11041011 - 3 Apr 2021

Cited by 8 | Viewed by 2489

Abstract

The aim of the study was to investigate the effect of iron oxide (Fe) and silver (Ag) nanoparticles (NPs) on ram semen. A skim milk extender without antibiotics was used as a diluent of 21 ejaculates (8 rams; 2–3 ejaculates/ram). The groups of control (C; semen without NPs), Fe NPs (3.072 mg Fe₃O₄/mL semen), and Ag NPs (2.048 mg Ag-Fe/mL semen) were incubated (15 °C; 30 min), and then a magnetic field was used for NPs’ removal. Standard microbiological procedures were performed for all groups. Post-treated samples were stored (15 °C) for 24 h, and sperm variables (kinetics by computer assisted sperm analysis (CASA); viability; morphology; HOST; DNA integrity) were evaluated at 6 and 24 h. Semen data were analyzed by a mixed model for repeated measures and microbiological data with Student’s t-test for paired samples. At 6 h of storage, VCL and rapid movement-spermatozoa, and at 24 h, total/progressive motility and amplitude of lateral head displacement (ALH) were significantly decreased in group Ag compared to control. In group Fe, progressive/rapid movement-spermatozoa were significantly lower compared to control after 24 h of storage. Only in group Ag was a significant reduction of total bacterial count revealed. In conclusion, the examined Fe NPs demonstrated slight antibacterial effect, while the examined Ag NPs provided higher antibacterial properties accompanied by cytotoxicity. Full article

(This article belongs to the Special Issue New Strategies to Manage Reproduction in Sheep- Starting with Embryos and Sperm)

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