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Dystocia in the horse is a life-threatening emergency. Prompt and effective intervention is essential to improve the outcome for both mare and foal. Resolution is possible via assisted vaginal delivery, controlled vaginal delivery, fetotomy or Caesarean section. Guidelines exist but the final choice is influenced by several factors including fetal viability, duration of dystocia, availability of obstetric assistance and financial considerations. The purpose of this study was to report our experience in the management of dystocia in Miniature horses and Shetland ponies. Data were collected from the records of 17 mares treated between 2020 and 2022. According to the clinic's protocol, correction was first attempted by assisted vaginal delivery; in case of failure, fetotomy or Caesarean section was performed. All mares were referred to the clinic after prolonged labor and only 2 (12%) were presented with their foal still alive. In 8/17 mares, the foal was delivered via assisted vaginal delivery. In 6/17 mares, a partial fetotomy was performed. In the 3 remaining cases, a conventional Caesarean section was proposed but not considered due to its financial cost; a field Caesarean section was therefore performed. General anesthesia was maintained using a continuous rate infusion of triple drip consisting of a combination of 250 ml sodium chloride (0.9%), 250 ml guaifenesin (10%), 20 ml ketamine (10%) and 1 ml detomidine (1%).After local anesthesia, a low left flank celiotomy in lateral recumbency was performed. Overall survival rate of the presented mares was 59% (10/17). Mares' survival rates following assisted vaginal delivery, fetotomy and field Caesarean section were respectively 63% (5/8), 33% (2/6) and 100% (3/3). Both foals alive at arrival survived delivery and one (6%) survived to discharge. While in warmblood horses, fetotomy has been proven rapid and safe (Norton et al. Equine Vet J 2007;39:37-41), in small breeds the feasibility of fetotomy is largely hampered by their body size and is deemed too stressful for the exhausted mares. In addition, complications after dystocia are aggravated in small breeds due to the high risk of hypertriglyceridemia and consequently hyperlipemia. Hypertriglyceridemia was determined in 35% (6/17) of the mares and hyperlipemia was the cause of death in 3 out of these 6 mares. Caesarean section is associated with several complications, such as retained placenta, metritis, laminitis and uterine hemorrhage. Due to a lack of asepsis in a non-optimal setting, peritoneal or incisional infections could be a weak point of the field Caesarean section. Our results, supported by those of others (Gandini et al. Reprod Dom Anim 2013;48:49-51), are promising for considering field Caesarean section as a preferable resolution to dystocia in Miniature horses and Shetland ponies. [ABSTRACT FROM AUTHOR]

The application of ovum pickup-intracytoplasmic sperm injection (OPU-ICSI) is well established for the commercial equine in vitro production (IVP). There is a marked individual mare effect on the OPU-ICSI outcome, but little is known about the influence of the mare's health conditions. This study aimed to determine a potential association between the concentrations of interleukin-6 (IL-6) and reactive oxygen metabolites (d-ROMs) in the serum of the donor mare on the efficiency of equine IVP. Just before OPU, a blood sample was collected from 28 Warmblood donor mares, that were subjected to a routine OPU-ICSI program. The serum concentrations of IL-6 and d-ROMs were photometrically assayed using the equine Nori® (Genorise Scientific, USA) and Diacron® (Diacron International, Italy) kits, respectively. The kinetics of blastocyst development and the blastocyst rate (blastocysts/injected oocytes) were recorded. For the blastocyst forming mares, Pearson's and Spearman's correlation coefficients were calculated between the blastocyst rate and the serum concentration of IL-6 and d-ROMs. The serum concentrations were also compared between mares yielding at least one and mares yielding no blastocyst or between mares with fast (at day 7-8 post ICSI) and slow (≥ day 9 post ICSI)growing blastocysts using the independent t-test or Mann-Whitney U-test. The average blastocyst formation rate was 24.68±5.16 % and the average concentrations of IL-6 and d-ROMs were 519.59±157.08 pg/mL and 171.30±4.55 carratelli units (UCARR), respectively. Serum concentrations of IL-6 and d-ROMs, respectively, were not significantly correlated with blastocyst formation rates and not markedly different between the blastocyst forming (552.68±235.18 pg/mL and 168.36±5.56 UCARR) and non-forming (468.47±179.99 pg/mL and 175.85±7.89 UCARR) mares. Serum concentrations of d-ROMs were significantly lower in mares with fast growing (148.10±8.13 UCARR) compared to those with slow growing blastocysts (179.41±4.89 UCARR; P= 0.003). Taken together, the serum concentration of IL-6 and d-ROMs are not associated with the mares' ability to produce blastocysts after OPU-ICSI. Although it may be questioned whether a single sample is representative of the mare's health status, changes in serum metabolites related to oxidative stress at the time of oocyte retrieval may diminish the OPU-ICSI outcome via interfering with the embryonic development in mares. Funded by the Ministry of Higher Education of the Arab Republic of Egypt. [ABSTRACT FROM AUTHOR]

Improved efficiency of ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) resulted to a steep increase in the number of in vitro produced (IVP) equine embryos worldwide. These IVP blastocysts are routinely cryopreserved and both slow freezing and vitrification result in high pregnancy rates. The use of minimal volume cryodevices and fast, multistep warming protocols can be challenging for veterinary practitioners receiving vitrified embryos, but direct warming in embryo holding medium supports embryo viability (Canesin et al. Theriogenology. 2020;151:151-158). The aim of this study was to compare pregnancy rates in a clinical OPU-ICSI program using a three-step vitrification/warming protocol vs. a commercial vitrification kit and direct warming in embryo holding medium. Embryos were produced in autumn and winter of 2021-2022 by OPU-ICSI (Papas et al. Animals. 2021;11:2004). Day of vitrification (7-12 post ICSI) was similar for both vitrification groups. Blastocysts were vitrified in a minimal volume on a Cryolock (Irvine Scientific) following two methods: (1) a three-step protocol (n=21): holding in basal vitrification medium (BVM; DMEM-F12 with 20% FCS), vitrification in BVM with 1.5M ethylene glycol (5 min), followed by BVM with 7M ethylene glycol and 0.6M galactose (40 s), and warming in warming medium (WM; DPBS with 0.1% glucose,36 mg/L pyruvate, and 0.4% BSA) with 0.3M sucrose (1 min), followed by WM with 0.15M sucrose (5 min) and holding in WM (5 min), all performed at 38.2°C (Choi and Hinrichs. Theriogenology. 2017; 87:48-54); (2) direct warming (n=21): vitrification at 23°C with a commercial VIT-Kit (Minitube, Germany) in VS1 (5 min), VS2 (5 min) and VS3 (40 s), containing increasing concentrations of glycerol and/or ethylene glycol, based on Eldridge-Panuska et al. (Theriogenology. 2005; 63:1308-1319), and direct warming at 38°C for 5 min in 4 ml of Emcare holding medium (Spervital, The Netherlands). For both protocols, warmed embryos were washed four times in Emcare and transferred immediately to a day 4 recipient mare. The effect of vitrification method on pregnancy rate at 14 days and 25 days was determined using binomial logistic regression analyses. Pregnancy rates at 14 and 25 days were respectively 66.7% and 47.6% for the three-step method and 76.2% and 52.4% for the direct warming. No difference was found between the two methods (p=0.496 and p=0.882, respectively). In conclusion, vitrification and warming of IVP blastocysts using commercial media and direct warming supports pregnancy and provides an easy method for embryo warming and transfer by equine veterinary practitioners. [ABSTRACT FROM AUTHOR]