The present study aimed to determinate the effect of external progesterone (P4) supplementation on luteolysis in cows under heat stress. Forty-eight (n=48) dairy cows in the period from ...July–September 2018 were part of and at day 35±3 postpartum scored for BSC, synchronized using PG-3-G + Ovsynch protocol and randomly allocated into two treatments: PRID group (n=27) treated with external P4 device between G1 and PGF
and CON group (n=21) left without treatment. Collection of blood samples to assess P4 concentrations was done at Pre-PG, at G1, at PGF
, at 72 h after PGF
(at timed artificial insemination TAI) and at d 21 after TAI. The pregnancy diagnosis was done at d 21 and d 30 after TAI by ultrasound. The average temperature-humidity index (THI) was 79.5±0.6. At G1, the P4 was significantly lower in the PRID group (1.84±0.99 ng/mL) in comparison to the CON group (2.97±1.82 ng/mL). In contrast, at PGF
, there was a tendency (p=0.09) of increased P4 concentration in PRID group compared with the CON group (4.26±1.68 and 3.74±2.39 ng/mL), respectively. At TAI, more PRID cows (p=0.0001) had a lower P4 (0.06±0.03 ng/mL), in comparison to CON (1.28±2.41 ng/mL). At d 21 and d 30 after TAI, more PRID cows were predicted and diagnosed pregnant (16/27 or 59.25% and 13/27 or 48.14%) compared with the CON group (11/21 or 52.38% and 8/21 or 38.08%) respectively, but without any significant differences. Supplementation of the P4 during the Ovsynch protocol increases the P4 before TAI and reduces the incomplete luteolysis in heat stressed dairy cows.
Artificial insemination (AI) as a part of assisted reproductive technologies represents the oldest and most widespread method used to accelerate genetic progress in all domestic animals. After its ...first implementation in ovine reproduction and almost 80 years afterward, AI is continuously used for improving the genetic merit, utilizing either fresh or short-time chilled semen. Nevertheless, regardless of the semen used for insemination, the conception rate (CR) is still lower in comparison to natural service. At least two factors are commonly thought to limit the success of the AI and reduce the CR: (1) failure of placing the semen directly into the uterus due to the specific anatomic structure of the ewe’s cervix; (2) lower viability of ram spermatozoa during cryopreservation (<30% progressively motile spermatozoa after thawing). This review elaborates on recent studies that aimed to achieve acceptable CR through the implementation of cervical or intrauterine insemination: deep intracervical, intrauterine trans-cervical, and intracornual. Several hormonal treatments (oxytocin, estrogen, or prostaglandin) were evaluated on inducing cervical dilation that facilitates insemination. A comprehensive analysis was given to the effects of several antioxidants (GSSG, GSH, and cysteine) supplemented in ram semen-freezing media. Sex-sorted ram semen fertility rate results were presented from our studies.
The present study aimed to evaluate whether the induction and the formation of an accessory corpus luteum (CL) after AI might increase the pregnancy per AI (P/AI) in heat stressed dairy cows. ...Starting at d 50±3 post-partum, 113 lactating Holstein cows from one commercial herd during summer were scored for body condition, blood sampled and examined by ultrasound. Those bearing a CL>25mm and progesterone (P4) level>2ng/mL were synchronized using a double PGF
α injection given 12 h apart and AI-ed at detected estrus. In total 18 cows, there were not any signs of estrus (n=10) nor a P4 level <2ng/mL at the time of enrolment (n=8) and therefore they were excluded from the study, leading to 95 cows finally enrolled.. At d5 post-AI, cows were randomly allocated into 2 groups: control group (CON, n=45) without any additional treatment, and treatment group (GnRH, n=50), treated with 0.008 mg Buserelin – a GnRH agonist. Blood sampling and ultrasound examination were done at d5, d14 and at d21 after AI, whereas the pregnancy diagnosis was done at d21 and d30 after AI. Average daily temperature and relative humidity values were used to calculate the temperature-humidity index (THI). The average THI during the experiment was 79.5±0.6. At d5, no differences were observed neither between the number of the CL nor between the P4 level in both groups. At d14 and d21, 82% of the GnRH-treated cows had more than one CL versus 0% of the CON cows. Both at d14 and 21, GnRH-treated cows had higher P4 levels compared to the CON cows (p<0.05). In addition, P/AI were higher in the GnRH group than in the CON group (65% vs. 48.3%, p<0.05), whereas late embryonic losses were higher in CON in comparison to GnRH cows (10.6 vs. 4%, respectively). The BCS at the moment of insemination did not affect P/AI (p>0.05). In conclusion, the induction of an accessory CL at d 5 after AI might increase P/AI in heat stressed dairy cows.
The objective of this study was to determine the effect of breed and equine chorionic gonadotropin (eCG) on ovarian response and in vitro embryo production from young goats. Thirty-one (12 Alpine, 10 ...Nubian, and 9 Saanen) were randomly assigned into three treatments of eCG (T1, 0 IU; T2, 500 IU; and T3, 1000 IU). Alpine goats showed the highest amount and largest size of follicles (
P
= 0.003). The effect of eCG dose 24 h post application was significant (
P
< 0.05), and was superior in goats undergoing T2. The aspiration rate of cumulus–oocyte complexes (COC) was 34% (
P
> 0.05), except for percentage of denuded oocytes, which obtained the highest number (
P
= 0.003) in the Saanen goats. The same difference was found (
P
= 0.02) in oocytes grade III in T2 and T3, with 42.5 and 37.9% respectively. In vitro embryo production was 80.0% of IVF/cleavage in the Alpine goats (
P
= 0.003). Embryo production was the greatest for T2 (69.2%;
P
= 0.004). T3 goats had higher percentage of morula stage (66.6%;
P
= 0.030). It is concluded that the application of eCG has a significant effect on the ovarian status, and quality and quantity of embryos with a differential response depending on the breed.
The aim of this study was to determine the semen quality, sexual behaviour and testosterone (T) levels in Saint Croix rams under semi-desert climate conditions. Sixteen rams (70.6 ± 12.5 kg; 24.1 ± ...0.3 months old) were randomly divided into a grazing group (GG, n = 8) and a supplemented group (supplemented individually with 1 kg.d
−1
of concentrate (156 g CP.kg
−1
DM and 2.5 Mcal EM.kg
−1
DM). SG, n = 8). Each group grazed on buffel, grass. Every two weeks, semen was collected, and sexual behaviour traits were evaluated. SG rams had greater body weight (P < 0.0001) and greater semen quality than the GG rams. SG rams had greater values for reaction time and lateral approaches than GG rams (P < 0.0001). No interaction was found between treatment and month for T concentration (P < 0.05); the SG rams had greater values during most of the months, but GG rams had greater values during September. Month had a significant effect on T concentration (P < 0.05) with the highest values in autumn. It can be concluded that Saint Croix rams are able to adapt to adverse environmental conditions and that supplementary feed prior to the mating season improves ram sexual behaviour.
Pet dogs very frequently develop spontaneous mammary tumors and have been suggested as a good model organism for breast cancer research. In order to obtain an insight into underlying signaling ...mechanisms during canine mammary tumorigenesis, in this study we assessed the incidence and the mechanism of canonical Wnt activation in a panel of 12 canine mammary tumor cell lines. We show that a subset of canine mammary cell lines exhibit a moderate canonical Wnt activity that is dependent on Wnt ligands, similar to what has been described in human breast cancer cell lines. In addition, three of the tested canine mammary cell lines have a high canonical Wnt activity that is not responsive to inhibitors of Wnt ligand secretion. Tumor cell lines with highly active canonical Wnt signaling often carry mutations in key members of the Wnt signaling cascade. These cell lines, however, carry no mutations in the coding regions of intracellular Wnt pathway components (APC, β-catenin, GSK3β, CK1α and Axin1) and have a functional β-catenin destruction complex. Interestingly, however, the cell lines with high canonical Wnt activity specifically overexpress LEF1 mRNA and the knock-down of LEF1 significantly inhibits TCF-reporter activity. In addition, LEF1 is overexpressed in a subset of canine mammary carcinomas, implicating LEF1 in ligand-independent activation of canonical Wnt signaling in canine mammary tumors. We conclude that canonical Wnt activation may be a frequent event in canine mammary tumors both through Wnt ligand-dependent and novel ligand-independent mechanisms.
Dans les élevages ovins et caprins, la maîtrise de la reproduction est importante pour une reproduction hors saison sexuelle, pour grouper les mises bas et pour la pratique de l’Insémination ...Artificielle (IA). Le traitement hormonal d’induction et de synchronisation de l’œstrus et de l’ovulation est aujourd’hui le moyen le plus efficace pour atteindre ces objectifs. Le recours à des traitements photopériodiques et/ou à l’effet mâle apparait comme une solution pour limiter l’utilisation d’hormones dans ces filières.Cet article rappelle les spécificités de la réponse ovulatoire et comportementale des femelles à « l’effet mâle », ainsi que les bases physiologiques qui contribuent à la réussite de cette pratique chez les ovins et les caprins. Le prétraitement des animaux avec des traitements photopériodiques de désaisonnement est un prérequis pour une réponse à l’effet mâle efficace, notamment chez des races très saisonnées comme les races caprines alpine et saanen. Des traitements lumineux sont actuellement disponibles en élevage pour une reproduction par effet mâle en toute saison. Toutefois, ils requièrent l’utilisation de mélatonine à certaines périodes de l’année (notamment pour une reproduction en période estivale). Cet article expose différents travaux réalisés pour développer de nouveaux traitements lumineux sans mélatonine, pouvant être appliqués en bâtiment ouvert. Des protocoles d’IA qui font appel à « l’effet mâle » sont en train d’émerger. Il s’agit pour certains de protocoles basés sur l’association de l’effet mâle avec des progestatifs et/ou des prostaglandines, et qui permettent de pratiquer une seule IA à un moment prédéterminé. Des protocoles d’IA après effet mâle seul (sans hormones) sont également disponibles, et notamment basés sur une détection des chaleurs. Chez les caprins, ils comportent 1 ou 2 moments d’IA, avec ou sans détection de chaleurs préalable. Chez les ovins, la détection des chaleurs est obligatoire pour la pratique de l’IA après un effet bélier seul. Dans les deux espèces, le développement de la détection automatisée des chaleurs facilitera le déploiement des protocoles d’IA sans utilisation d’hormones.
This study aimed to evaluate the effect of reinserting controlled internal drug release (CIDR) devices after fixed-time artificial insemination (FTAI) on pregnancy rates in goats. Oestrus was ...synchronized with a short (5 days) CIDR protocol, and FTAI was conducted 54 hours after CIDR removal. According to the reinsertion of CIDR after FTAI, goats were assigned to three treatments: G0 control group (n = 29), no CIDR reinsertion; G7 group (n = 27), CIDR reinserted 7 days; G14 group (n = 29), CIDR reinserted 14 days. Blood samples were collected to determine progesterone levels. Oestrus appearance (92.9%), interval of CIDR removal to oestrus (IRE = 34.1 ± 1.1 hours), interval of oestrus onset to artificial insemination (IEAI = 20.2 ± 1.0 hours), mean duration of oestrus (38.4 ± 1.4 hours), and pregnancy rates (61.0%) were similar (P > .05) among groups. Progesterone concentrations were higher (P < .05) in G7 and G14 than G0 goats. G7 goats had lower (P < .05) oestrus rate, after CIDR reinsertion, than G0 and G14 goats. Overall pregnancy rate was similar (P > .05) for all groups. In conclusion, reinsertion of CIDR for 7 or 14 days after a short oestrus synchronization protocol and FTAI did not increase the overall pregnancy rate of goats.
The aim of this research was to evaluate ultra rapid OPS vitrification on the embryo viability. The OPS vitrification technique is comprised of ultra rapid freezing of a small drop in which the ...embryo is placed. Before the thin straw was plunged into the liquid nitrogen, the embryos were treated with highly concentrated cryoprotectant (CPA) solutions as follows: 18% ethylene glycol (EG), 18% dimethyl-sulfoxide (DMSO) and 0.4 M sucrose. Surgical transfer into the recipient mares and morphologic examination of recollected embryos were used to measure the viability of transferred embryos. The research was performed on Welsh pony mares by collecting the embryos 6.75 days after ovulation. Twenty embryos were vitrified and transferred, four in each recipient mare. At day twelve, nine embryos were recollected after flushing of the recipient uterus (56%, 9/16). In one recipient mare, endometritis was detected when the uterus was flushed. Among the sixteen recollected embryos, seven (44%) had normal morphology and well developed embryonic vesicles. The vitrification procedure used proved to be encouraging. Key words: horse, embryo, cryopreservation, open pulled straw, vitrification, transfer Svrha istrazivanju bila je ustanoviti ucinkovitost ultrabrze vitrifikacije u otvorenoj rastegnutoj slamci na vitalnost konjskih zametaka, prijenosom vitrificiranih pa otopljenih zametaka u sinkronizirane primateljice. Istrazivanje je provedeno na stadu Welsh poni kobila. Davateljicama zametaka matemice su transcervikalno bile ispirane 6,75 dana nakon ovulacije, a zametci su nakon vitrifikacije bili pohranjeni u spremnik s tekucim dusikom. Nakon odmrzavanja, zametci su bili prenijeti u sinkronizirane primateljice. Maternice primateljica bile su ispirane petoga dana nakon prijenosa odmrznutih zametaka. Ukupno je bilo preneseno dvadeset zametaka, a ispiranjem maternica primateljica dobiveno je devet zametaka sto iznosi 56% s obzirom da je u jedne primateljice ispiranjem ustanovljen endometritis. Od zametaka dobivenih ispiranjem primateljica, sedam (44%) je imalo morfoloski normalno razvijene zametne mjehure. Na osnovi provedenih istrazivanja zakljuceno je da su rezultati ostvareni vitrifikacijom u otvorenoj rastegnutoj slamci ohrabrujuci, ali bi ih s obzirom na mali broj prenijetih zametaka trebalo potvrditi na vecem uzorku, posebice sa zametcima odabranoga promjera to brojem zdrebadi. Kljucne rijeci: konj, zametak, krioprezervacija, vitrifikacija, transfer
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