Effect of increased serum progesterone on luteal morphology and function, pregnancy, and gestational loss in Nelore cows.

The aim of the present study was to determine the impact of different strategies for increasing the level of serum progesterone (P4) on luteal morphology and function in bovine females. The effects of increasing P4 on pregnancy rate and gestational loss (GL) in Nelore cows subjected to timed artificial insemination (TAI) were also evaluated. A total of 939 cows were divided into three groups: P4LA (n = 305), 150 mg of long-acting injectable P4 7 days after TAI; GnRH (n = 306), 10 µg of buserelin acetate 7 days after TAI; and control (n = 328), no hormone treatment after TAI. Doppler ultrasound assessments and P4 measurements were performed on days 7 and 16 after TAI. The pregnancy rate and GL as a function of treatment were compared using the SAS GLIMMIX procedure. Corpus luteum (CL) vascular perfusion, volume, and plasma P4 concentration were analysed using the SAS PROC MIXED procedure. No significant difference was found among the treatments in terms of volume, number of pixels, and CL intensity or in the serum P4 concentration at 7 days after ovulation. The CL blood flow at 16 days after ovulation was lower in the P4LA and GnRH groups than that in the control group (p < .01). Serum concentrations of P4 at 16 days after ovulation were higher in the P4LA and GnRH groups than those in the control group (p = .04). A difference in the pregnancy rate (p = .003) and a trend in GL (p = .07) as a function of treatment were found. Overall, long-acting injectable P4 supplementation on day 7 after TAI or GnRH administration affected CL vascularization and increased the serum concentrations of P4 16 days after ovulation, promoting better pregnancy rates than the control.

Embryo-endometrial interaction associated with the location of the embryo during the mobility phase in mares.

Embryo-maternal crosstalk is essential to establish pregnancy, with the equine embryo moving throughout the uterus on days 9-15 (ovulation = day 0) as part of this interaction. We hypothesized that the presence of a mobile embryo induces local changes in the gene expression of the endometrium. On Day 12, the endometrial transcripts were compared among three groups: uterine horn with an embryo (P+, n = 7), without an embryo (P-, n = 7) in pregnant mares, and both uterine horns of nonbred mares (NB, n = 6). We identified 1,101 differentially expressed genes (DEGs) between P+ vs. NB and 1,229 DEGs between P- vs. NB. The genes upregulated in both P+ and P- relative to NB were involved in growth factor pathway and fatty acid activation, while downregulated genes were associated with oxytocin signaling pathway and estrogen receptor signaling. Comparing the transcriptome of P+ to that of P-, we found 59 DEGs, of which 30 genes had a higher expression in P+. These genes are associated with regulating vascular growth factors and the immune system, all known to be essential in early pregnancy. Overall, this study suggests that the mobile embryo influences the endometrial gene expression locally.

Mitigation of low pregnancy rate in excitable Nellore cows by administration of GnRH or P4.

This research aimed to determine the effect of temperament on reproductive parameters including cortisol and progesterone (P4) in Nellore cows. Additionally, two methods for increasing plasma progesterone (P4) levels in excitable animals to enhance pregnancy rate (P/AI) and reduce pregnancy loss were investigated. In total, 939 cows were subjected to timed artificial insemination (TAI) and divided into three groups: (P4LA; n = 305) 150 mg of injectable long-acting progestogen 7 days after TAI; (GnRH; n = 306), 10 µg of buserelin acetate on day 7 after TAI; control group (CG; n = 328) without hormonal treatment. In 213 cows, randomly chosen from each group, ultrasound evaluations of the preovulatory follicle (Mode B) were performed on the day of insemination and of the corpus luteum (Color Doppler) 7 and 16 days after TAI. Blood samples were obtained from 20% of the 939 animals, randomly chosen from each group, on the day of insemination and after 7 and 16 days to measure cortisol and progesterone, respectively. At the time of insemination, subjective temperament evaluations were performed with the animals being classified as excitable (EXC) or adequate (ADQ). The SAS GLIMMIX procedure was used to compare the pregnancy rate (P/AI) and gestational loss within each temperament for the three experimental groups. Continuous variables were analyzed utilizing SAS PROC MIXED procedure. Cortisol concentration was higher and POF (preovulatory follicle) and CL (corpus luteum) volumes at the time of insemination and 7 days after AI, respectively, were lower in EXC animals than in ADQ. No significant difference was observed between the number of pixels, CL intensity, and plasma concentration of P4, 7 days after TAI. However, 16 days post-insemination, among the animals classified as EXC, higher concentrations of P4 were observed in the GnRH and P4LA groups than in the control. Regarding P4 concentrations, there was a tendency to be lower in animals classified as EXC than in ADQ within the control group (P = 0.06), while rate of blood flow from the CL was lower in EXC animals than in ADQ animals (P = 0.04). Among the ADQ animals, the GnRH and P4LA groups showed a lower CL flow rate than that observed in the control (P = 0.04), 16 days after the TAI. Among EXC animals, a higher pregnancy rate was observed in the GnRH and P4LA groups than in the control group (P = 0.01). In the control group, the pregnancy rate (P/AI) of the ADQ animals was higher than that of the EXC animals (P = 0.05). No statistically significant differences were observed between gestational losses when the treatments or temperaments were compared. In conclusion, the use of GnRH or P4LA, 7 days after insemination, improves pregnancy rates in excitable animals and is a viable alternative to minimize the negative impact of stress and improve reproductive efficiency in beef cattle.

Development of a novel 21-day reinsemination program, ReBreed21, in Bos indicus heifers.

The aim was to develop a program for resynchronization of ovulation (ReBreed21) that allowed reinsemination of non-pregnant Bos indicus heifers every 21 d using timed AI (TAI) without the need for detection of estrus. The Rebreed21 program begins 12 d after previous TAI (Day 0) by inserting an intravaginal P4 implant (Day 12) that is removed 7 d later (Day 19) combined with treatment with 300 IU of eCG. On Day 21, early pregnancy diagnosis (Doppler PD) is performed based on CL vascularity. Non-pregnant (NP) heifers immediately received AI combined with 100 µg of GnRH. The program is replicated 12 d after second TAI to produce a breeding season (BS) of 42 d with 3 potential TAIs. Two experiments were conducted as a proof of concept for this rapid rebreeding program. In Experiment 1, 76 heifers were enrolled in ReBreed21, as explained above. In Experiment 2, 300 Nellore heifers were synchronized for 1st TAI and randomly assigned to one of two groups: ReBreed21 (n = 147) or another early resynchronization procedure, Resynch14 (n = 153) with P4 implant inserted 14 d after previous TAI plus 50 mg of long-acting injectable P4; 8 d later P4 implant removed (Day 22) and early Doppler PD performed; NP heifers received 150 µg of cloprostenol, 0.5 mg of ECP, and 300 IU of eCG with TAI on Day 24. In both experiments, the largest follicle (LF) was measured at each Resynch TAI. Ultrasound was later used to confirm the early Doppler PD and to determine ovulation (OV) to Resynch at 12 d after TAI in ReBreed21 (Day 33 of pregnancy) and 14 d after TAI in Resynch14 (Day 38 of pregnancy). Final PD was performed 40 d after 3rd TAI. Results for Experiment 1 were: diameter of LF 11.8 ± 0.23 mm; 88.9% OV; 20.5% false positives; 38.1% P/AI at 1st TAI; 44.4% overall P/AI for ReBreed21 TAIs; 72.3% total pregnant at end of BS. In experiment 2, Rebreed21 vs. Resynch14 were different for: diameter of LF (10.9 ± 0.17 vs. 10.0 ± 0.17 mm, P = 0.0003), heifers with LF < 8.5 mm (10.2 vs. 26.4%, P = 0.04), or LF ≥ 11 mm (50.0 vs. 37.2%, P = 0.001), and P/AI at first TAI (29.3% [43/147] vs. 20.3% [31/153], P = 0.074) but similar for OV (overall 86.8% [239/275], P = 0.82), false positives (P = 0.52) overall P/AI for Resynch TAIs (33.6 vs. 28.8%, P = 0.4), and total pregnant at end of BS (58.5% [86/147] vs. 55.6% [85/153], P = 0.64). In addition, median time to pregnancy was 9 d earlier (P = 0.0007) for ReBreed21 than Resynch14. Thus, ReBreed21 is a novel protocol that allows earlier reinseminations than Resynch14 but with similar fertility.

Central Nervous System and Vertebrae Development in Horses: a Chronological Study with Differential Temporal Expression of Nestin and GFAP.

The neural system is one of the earliest systems to develop and the last to be fully developed after birth. This study presents a detailed description of organogenesis of the central nervous system (CNS) at equine embryonic/fetal development between 19 and 115 days of pregnancy. The expression of two important biomarkers in the main structure of the nervous system responsible for neurogenesis in the adult individual, and in the choroid plexus, was demonstrated by Nestin and glial fibrillary acid protein (GFAP) co-labeling. In the 29th day of pregnancy in the undifferentiated lateral ventricle wall, the presence of many cells expressing Nestin and few expressing GFAP was observed. After the differentiation of the lateral ventricle wall zones at 60 days of pregnancy, the subventricular zone, which initially had greater number of Nestin+ cells, began to show higher numbers of GFAP+ cells at 90 days of pregnancy. A similar pattern was observed for Nestin+ and GFAP+ cells during development of the choroid plexus. This study demonstrates, for the first time, detailed chronological aspects of the equine central nervous system organogenesis associated with downregulation of Nestin and upregulation of GFAP expression.

Prenatal development of the digestive system in the horse.

Since the horse has a highly precocial reproductive strategy, most organs are functionally well developed at birth and thus, embryonic and fetal life is interesting. Data on the development of important organs are very limited. Here, we detailed macroscopically and histologically the equine digestive system, focusing on the first third of gestation. At 21 days, the oral cavity was an empty space, and the liver contained proliferating endodermal cells. At 25 days, a fusiform stomach and the pancreatic bud were present. At 28 days, a small tongue and the esophagus occurred. At 30 days, primary and secondary palates were developed, the liver contained cords of hepatocytes, and the pancreas was triangular. At 40 days, crypts had formed in the intestinal loops, cell differentiation was observed in the hepatic parenchyma, and the pancreas was elongated. Pancreatic acini and islets were observed in fetuses of 50 days and intestines were highly convoluted. Three segments of the pharynx were distinguishable at 75 days. At 105 days, the intestinal villi were wide with round tips; especially, the liver, stomach, and oral cavity showed key steps of anatomical and cellular differentiation in early fetuses, whereas other areas, such as pancreas or pharynx were still immature in the investigated phase. Pluripotency analysis using Oct4 showed initial intense staining in all of the digestive system tissues and a later decreased becoming restricted to specific cell layers. In conclusion, our data may contribute to perform a chronological reference of developmental events for approaches predicting pregnancy disorders in horses.

Taxa de recuperação e características morfológicas de embriões muares (Equus caballus x Equus asinus) / Recovery rate and morphologic features of cross bred embryos (Equus caballus x Equus asinus)

A Transferência de Embrião (TE) contribuiu efetivamente para a produção de equinos e outras espécies. O mercado de muares tem apresentado um contínuo crescimento, entretanto, a aplicação das biotecnologias para a produção desses animais ainda é escassa. O presente estudo avaliou a taxa de recuperação embrionária e as características dos embriões provenientes do cruzamento de éguas com jumentos. Os embriões foram recuperados entre os dias 6 e 9 após a ovulação, dessa forma foi realizada a avaliação da taxa de recuperação embrionária e avaliação das características relacionadas com a idade, morfologia e diâmetro embrionário. A taxa de recuperação embrionária total foi de 55,9% (71/127), e não apresentou diferença para as colheitas realizadas em diferentes dias (D6-D9). Foram recuperados embriões nos estágios de mórula, blastocisto inicial, blastocisto e blastocisto expandido. O tamanho dos embriões variou entre 147-1688μm e a média do diâmetro de todos os embriões recuperados foi de 438,04μm. A recuperação de embriões muares pode ser realizada entre os dias 6 e 9 após a ovulação, e propicia a recuperação de embriões nos primeiros estágios de desenvolvimento.(AU)

Production biotechnologies, particularly embryo transfer (ET) has constantly been contributed to reproduce horses and other species. The mules market has shown continuous growth, however, the biotechnology for mule assisted reproduction is still scarce. The aim of this study was to evaluate the embryo recovery rate and the features of the embryos from mares bred with donkeys. The embryos recovery attempts were performed on days 6 to 9 after ovulation, in order to evaluate the embryo recovery rate and the features related to age, morphology and embryonic diameter in each day. The overall embryo recovery rate was 55,9% (71/127), and there was no significant difference (p>0,05) on different days (D6-D9). Embryos were recovered in stages of mórula, early blastocyst, blastocyst and expanded blastocyst. The diameter of the embryos ranged from 147-1688μm and the mean diameter of all the embryos collected was 438,04μm. The collection of hybrid embryos might be performed between days 6 and 9 after ovulation, and provides recovery of embryos in the early stages of development.(AU)

Surtos de dermatite ulcerativa causados por espinhos de Mimosa setosa, M. debilis e M. pudica (Fabaceae) em equinos / Ulcerative dermatitis outbreaks caused by thorns of Mimosa setosa, M. debilis and M. pudica (Fabaceae) in horses

Descrevem-se, na pele de equídeos, lesões de natureza mecânico-traumática causadas por espinhos de Mimosa spp. Dentre as três espécies da planta identificadas como responsáveis pelas lesões, M. setosa estava presente em maior quantidade (80%) e M. debilis e M. pudica encontravam-se em menor proporção na pastagem. Ocorreram três surtos de dermatite ulcerativa em períodos chuvosos de abril a maio de 2013, dezembro de 2013 a fevereiro de 2014 e abril a maio deste mesmo ano. Vinte e cinco equinos do Setor de Reprodução Animal da Universidade Federal Rural do Rio de Janeiro apresentaram, na pele, lesões ulcerativas com contornos irregulares, exsudato hemorrágico, recobertas por crostas. As lesões localizavam-se sobretudo nas regiões de quartela, boleto, articulação escapulo-umeral, lábios superior e inferior, focinho, narinas, bochechas e chanfro. Sete animais foram biopsiados e o exame histopatológico revelou ulceração da epiderme e infiltrado inflamatório constituído por macrófagos e neutrófilos, delimitado por tecido de granulação subjacente. Em alguns casos, foram observados microespículos das referidas plantas (tricomas hirsutos) em meio à reação inflamatória. O diagnóstico de dermatite cutânea causada pela ação traumática da planta baseou-se na presença de Mimosa spp. na pastagem, nas características e localização das lesões na pele dos equinos, nos achados histopatológicos e na recuperação após a retirada dos animais do pasto.(AU)

Mechanic natural skin lesions in horses caused by thorns of Mimosa spp. are described. Between the three plant species identified as responsible for the lesions, Mimosa setosa was present in greater quantity (80%) in the pasture, whilst M. debilis and M. pudica existed in lower proportion. Three ulcerative dermatitis outbreaks were observed during rainy periods of April to May 2013, December 2013 to February 2014 and April to May of the same year. Twenty-five horses from the Sector of Animal Reproduction, Federal Rural University of Rio de Janeiro, showed ulcerative skin lesions with irregular borders, hemorrhagic exudate, sometimes covered with scabs, located mainly in the regions of the pastern, fetlock, scapular-humeral joints, upper and lower lips, nose, nostrils, cheeks and chamfer. Seven horses were biopsied and histopathological examination revealed ulceration of the skin with inflammatory infiltrate by macrophages and neutrophils, delimited by granulation tissue. In some cases, microspicules of these plants (hirsute trichomes) were found throughout the inflammatory reaction. The diagnosis of skin dermatitis, caused by traumatic action of the plants, was based on the presence of Mimosa spp. in the pasture, on the characteristic clinic-pathological features and on recovery of the horses after their removal from the pasture. This appears to be the first report of the occurrence of ulcerative dermatitis caused by Mimosa setosa, as dermatitis caused by the others has been described before.(AU)

Reproductive efficiency of asymptomatic Theileria equi carriers mares submitted to an embryo transfer program / Eficiência reprodutiva de éguas portadoras assintomáticas de Theileira equi submetidas a um programa de transferência de embriões

This study aimed to assess and evaluate the effects of Theileria equi infection on embryonic recovery, gestation and early embryonic loss. Thirteen Mangalarga Marchador Theileria equi positive donors (diagnosed through nested-PCR) and 40 embryos receptors were used. Donors were submitted to two embryo collections in two consecutive estrous cycles (GId); after, the same mares were treated with imidocarb dipropionate (1.2mg/kg IM.) in order to collect more embryos in two more estrous cycles (GIId). Receptors were divided into two groups (control and with treated) with 20 animals each, where one group was the control (GIr) and the other one (GIIr) treated with 1.2mg/kg IM of imidocarb dipropionate assessing the gestation rate at 15, 30, 45 and 60 days. After 52 embryo collections, the embryonic recovery rates were 53.84% (14/26) and 65.38% (17/26) (p> 0.05) for GId and GIId, respectively. The gestation rate was 70% (14/20) (p>0.05) at 15, 30, 45 and 60 days in group GIr and for GIIr was 85% (17/20) (p>0.05) at 15 days, 80% (16/20) (p>0.05) at 30, 45 and 60 days. The treatment with imidocarb dipropionate did not cause significant improvement in the reproductive efficiency at an ET program.

Este estudo teve por objetivo avaliar a influência da infecção por Theileria equi nas taxas de recuperação embrionária, gestação e perda embrionária precoce. Foram utilizadas 13 doadoras e 40 receptoras de embrião da raça Mangalarga Marchador, positivas para Theileria equi através da técnica de nested-PCR. Nas doadoras foram realizados duas coletas de embriões em dois ciclos estrais consecutivos (GId), em sequência, esses mesmos animais foram tratados com dipropionato de imidocarb (1,2mg/kg IM.) para realização de mais duas coletas de embriões em dois ciclos estrais (GIId). As receptoras foram divididas em dois grupos de 20 animais cada, onde um grupo foi o controle (GIr) e, o outro grupo, foi tratado (GIIr) com 1,2mg/ Kg IM de dipropionato de imidocarb, com intuito de avaliar a taxa de gestação aos 15, 30, 45 e 60 dias. Após a realização de 52 coletas de embrião, as taxas de recuperação embrionária foram de 53,84% (14/26) e 65,38% (17/26) (p> 0,05) para GId e GIId, respectivamente. A taxa de gestação foi de 70% (14/20) (p>0,05) aos 15, 30, 45 e 60 dias no grupo GIr e para o GIIr foi 85% (17/20) (p>0,05) aos 15 dias, 80% (16/20) (p>0,05) aos 30, 45 e 60 dias. O tratamento com dipropionato de imidocarb não promoveu melhora significativa na eficiência reprodutiva em um programa de TE.