Streptococcus equi subsp. zooepidemicus: High molecular diversity of Argentinian strains isolated from mares with endometritis.

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a mucosal commensal of the lower genital tract in horses and is the most isolated bacterium causing endometritis in mares. The aim of this study was to determine the molecular diversity of S. zooepidemicus obtained from endometritis in mares in Buenos Aires province, Argentina. Thirty isolates obtained from the uterus of mares in 2005 and 2017 were studied. The MLST scheme was applied to identify the Argentinian genotypes and the clonal relationships and patterns of evolutionary descent were identified using the eBURST algorithm - goeBURST. Twenty six different Sequence types (STs) were identified, being only 11 of them previously reported in horses and also, from several host species and tissues. The other 15 STs were reported in Argentinian reproductive strains of mares in our study for the first time. The genotypes obtained from uterus in Argentina were not evenly distributed when all the published S. zooepidemicus STs were analysed, thus, it was not possible to establish that the same lineage circulates in our equine population. The fact that the identified genotypes were also reported in other countries, diverse samples and host species suggest that there is not a host, and an anatomical niche adaptation. Finally, the isolation of the same genotype in the vagina/clitoris and the uterus of the same mare highlights the versatility of S. zooepidemicus and its role as an opportunistic pathogen.

Antimicrobial Resistance and Extended-Spectrum Beta-Lactamase Genes in Enterobacterales, Pseudomonas and Acinetobacter Isolates from the Uterus of Healthy Mares.

Antibiotic-resistant bacteria are a growing concern for human and animal health. The objective of this study was to determine the antimicrobial resistance and extended-spectrum beta-lactamase genes in Enterobacterales, Pseudomonas spp. and Acinetobacter spp. isolates from the uterus of healthy mares. For this purpose, 21 mares were swabbed for samples, which were later seeded on blood agar and MacConkey agar. The isolates were identified using MALDI-TOF and the antimicrobial susceptibility test was performed using the Kirby-Bauer technique. To characterize the resistance genes, a polymerase chain reaction (PCR) scheme was performed. Of the isolates identified as Gram-negative, 68.8% were Enterobacterales, represented by E. coli, Enterobacter cloacae, Citrobacter spp., and Klebsiella pneumoniae; 28.1% belonged to the genus Acinetobacter spp.; and 3.1% to Pseudomonas aeruginosa. A 9.3% of the isolates were multidrug-resistant (MDR), presenting resistance to antibiotics from three different classes, while 18.8% presented resistance to two or more classes of different antibiotics. The diversity of three genes that code for ESBL (blaTEM, blaCTX-M and blaSHV) was detected in 12.5% of the strains. The most frequent was blaSHV, while blaTEM and blaCTX-M were present in Citrobacter spp. and Klebsiella pneumoniae. These results are an alarm call for veterinarians and their environment and suggest taking measures to prevent the spread of these microorganisms.

Equine Placentitis in Mares Induces the Secretion of Pro-Inflammatory Cytokine eIL-1ß and the Active Extracellular Matrix Metalloproteinase (MMP)-9.

Equine placentitis is characterized by infection and inflammation of the placenta. Different biomarkers associated with this inflammatory response have been evaluated in experimentally induced equine placentitis, but not in pregnant mares with spontaneous placentitis. The aim of the current study was to determine the concentration of eIL-1ß and the activity of proMMP-2 and proMMP-9 in the serum of healthy mares and mares with placentitis on days 240 and 320 of gestation to explore whether these biomarkers are associated with equine maternal placentitis and/or with the birth of an infected or inviable foals. Serum samples were collected from sixteen pregnant English Thoroughbred mares, retrospectively classified as follows: (1) healthy mares with full-term gestation; and (2) mares with ultrasonographic signs of placentitis. The health of each foal was examined at birth, and it was decided to classify the cases into four groups: (1) healthy mares delivering a healthy foals (HM-HF, n = 6); (2) mares with USP delivering a healthy foal (USP-HF, n = 3); (3) mares with USP delivering a live septic foal (USP-LSeF, n = 4); and (4) mares with USP delivering a dead foal (USP-DF, n = 3). eIL-1ß was quantified by ELISA, and proMMP-2 and proMMP-9 activity by gelatin zymography electrophoresis. In healthy mares, the serum concentrations of eIL-1ß underwent a significant 16.5-fold increase from day 240 to day 320 of gestation. Although similar results were found in the mares with ultrasonographic signs of placentitis that delivered a healthy foal, those delivering a live septic or nonviable foal exhibited much higher concentrations of eIL-1ß. proMMP-2 and proMMP-9 activity was not associated with maternal placentitis, foal infection, or death. Hence, the presence of placentitis severe enough to affect the health of the foal can be confirmed or discarded by determining the eIL-1ß concentration in mares that have shown ultrasonographic signs of placentitis.

Progesterone Device Use Improves Ovum Pick-Up Efficiency in Acyclic Donors.

The aim of this study was to evaluate follicular dynamics and ovum pick-up (OPU) efficacy in untreated mares or mares treated with an intravaginal progesterone (P4) device during seasonal anestrus (acyclic) and during the breeding season (cyclic). Six mares (mean age = 5 years), were recruited into an ovum pick-up scheme that was performed every 14 days with and without the P4 device, during the acyclic and cyclic phases. Aspirations amounted to seven procedures with or without the P4 device during each phase. Five ultrasound assessments were performed at each interval between the OPUs. Data on follicular number and diameter as well as the numbers of recovered and the percentage of recovered oocytes were also collected. The number of follicles from mares in the acyclic phase was higher (P < .005) regardless of the treatment. However, the follicular diameter was smaller for the P4 group (P < .005) from the 2nd to the 5th evaluation post-OPU procedure. The percentage of oocytes recovered during the acyclic phase was higher for mares treated with the P4 device (P < .005). The P4 device resulted in follicles with smaller diameters and facilitated OPU efficacy.

Plasma Estradiol Profile After Administration of Different Types of Estradiol Esters in Acyclic Mares.

Although the use of different estradiol esters has been extensively studied in hormonal protocols in cows, such information is lacking in mares. The present study aimed to assess the effects of treatment with the same doses and administration frequency of estradiol cypionate, estradiol benzoate and 17ß estradiol on plasma estradiol (E2) concentrations of acyclic mares and correlate the E2 profile to the endometrial edema score. Sixteen treatments were performed in 14 mares randomly divided into three groups: EB (n = 5), EC (n = 5), and 17ß (n = 6), receiving 10 mg on day 0 (D0), 6 mg on D1, and 4 mg on D2 of estradiol benzoate, estradiol cypionate, and estradiol 17ß, respectively. Blood samples, rectal palpations, and ultrasound evaluations were performed once daily, starting before the first estradiol treatment (D0) until edema disappearance or D8. Moderate to high edema was observed in all groups 24 hours after the first estradiol administration. Edema persisted above score 2 until D7, D5, and D4 in groups EC, EB, and 17ß, respectively. Higher edema was found on D2 in EB group compared to 17ß, on D6 and D7 in EC compared to 17ß, and on D8 in EC compared to EB (p ≤ .05). Maximum E2 concentrations were detected on D1 in groups: EB, showing a sharp decrease from D2 to D3 (p < .0001); and 17ß, where no differences were observed between treatment days (p ≥ .05). In the EC group, maximum concentrations were observed on D2, which remained high from D2 to D4 compared to the other days (p < .0001). Plasma concentration of E2 was higher in EB than the other groups on D0 and D1, and EB>EC>17ß on D2. Plasma E2 concentrations and edema score were positively correlated, being moderate in groups EB and EC and weak in the 17ß group. In conclusion, the most pronounced plasma E2 concentration was observed in EB group 24 hours after the administration of the first dose. Estradiol concentrations peaked 48 hours after EC administration, while a distinct peak was not observed in a 24h interval evaluation in the 17ß group. Moreover, high edema does not necessarily reflect on high E2 concentrations in acyclic mares.

Seasonal Variation of Melatonin Concentration and mRNA Expression of Melatonin-Related Genes in Developing Ovarian Follicles of Mares Kept under Natural Photoperiods in the Southern Hemisphere.

This study investigated the seasonal variations in mRNA expression of FSH (Fshr), LH (Lhr) receptors, melatonin (Mt1 and Mt2) receptors, melatonin-synthetizing enzymes (Asmt and Aanat) and melatonin concentration in developing follicles from mares raised in natural photoperiods. For one year, ultrasonographic follicular aspiration procedures were performed monthly, and small (<20 mm), medium (20 to 35 mm) and large (>35 mm) follicles were recovered from five mares. One day before monthly sample collections, an exploratory ultrasonography conducted to record the number and the size of all follicles larger than 15 mm. The total number of large follicles were higher during the spring/summer (8.2 ± 1.9) than during autumn/winter (3.0 ± 0.5). Compared to autumn/winter seasons, there was an increase of Fshr and Aanat mRNA expressions in small, medium and large follicles, an increase of Lhr and Asmt mRNA expressions in medium and large follicles and an increase of Mt1 and Mt2 mRNA expressions in small and large follicles during spring/summer. The melatonin levels in follicular fluid were also higher during the spring/summer seasons. The present data show that melatonin locally upregulates the mRNA expression of Mt1 and Mt2 receptors and melatonin-forming enzymes in mare developing follicles during reproductive seasons.

Aborto infectocontagioso em éguas: uma revisão bibliográfica / Infectious-contagious abortion in mares: a literature review / Aborto infecto-contagioso en yeguas: una revisión de la literatura

O aborto infectocontagioso em éguas é um tema de grande relevância e interesse para os médicos veterinários e criadores de equinos. Além dos impactos econômicos decorrentes de perdas e redução das taxas reprodutivas, os surtos de abortos causados por doenças infectocontagiosas representam uma ameaça significativa para a saúde equina. Neste trabalho, realizamos uma revisão bibliográfica abrangente sobre as principais doenças que causam abortos infecciosos em éguas. Nosso objetivo é fornecer uma visão geral das patologias mais relevantes nesse contexto, abordando suas características clínicas, epidemiologia, diagnóstico e medidas de controle. Para isso, realizamos uma busca em bancos de dados renomados, como o PubMed e o Scopus, por artigos científicos relevantes publicados nos últimos dez anos. As informações selecionadas foram cuidadosamente analisadas, comparadas e sintetizadas, com o intuito de identificar as principais doenças e suas implicações na saúde reprodutiva das éguas. Esta revisão pretende auxiliar veterinários, pesquisadores e profissionais da área a compreenderem melhor essas doenças e desenvolverem estratégias eficazes de prevenção e controle.(AU)

El aborto infeccioso en yeguas es un tema de gran relevancia e interés para veterinarios y criadores de equinos. Además de las repercusiones económicas derivadas de las pérdidas y la reducción de las tasas reproductivas, los brotes de aborto causados por enfermedades infecciosas representan una importante amenaza para la salud equina. En este artículo, realizamos una revisión exhaustiva de la literatura sobre las principales enfermedades que causan abortos infecciosos en yeguas. Nuestro objetivo es ofrecer una visión general de las patologías más relevantes en este contexto, abordando sus características clínicas, epidemiología, diagnóstico y medidas de control. Para ello, buscamos en bases de datos de renombre como PubMed y Scopus artículos científicos relevantes publicados en los últimos diez años. La información seleccionada fue cuidadosamente analizada, comparada y sintetizada con el fin de identificar las principales enfermedades y sus implicaciones en la salud reproductiva de las yeguas. El objetivo de esta revisión es ayudar a veterinarios, investigadores y profesionales del sector a comprender mejor estas enfermedades y desarrollar estrategias eficaces de prevención y control.(AU)

Infectious abortion in mares is a topic of great relevance and interest for veterinarians and equine breeders. In addition to economic impacts from losses and reduced reproductive rates, abortion outbreaks caused by infectious diseases represent a significant threat to equine health. In this paper, we conduct a comprehensive literature review on the major diseases that cause infectious abortions in mares. Our goal is to provide an overview of the most relevant pathologies in this context, addressing their clinical features, epidemiology, diagnosis, and control measures. To this end, we searched renowned databases such as PubMed and Scopus for relevant scientific articles published in the last ten years. The selected information was carefully analyzed, compared and synthesized in order to identify the main diseases and their implications in the reproductive health of mares. This review aims to assist veterinarians, researchers, and professionals in the field to better understand these diseases and develop effective prevention and control strategies.(AU)

A arte de inseminar éguas com sêmen congelado / The art of inseminating mares with frozen semen

Nos últimos quinze anos, a equideocultura foi uma atividade em destaque com significativo crescimento no Brasil e no mundo. O Brasil é o segundo país no mundo que mais utiliza transporte de sêmen equino, ficando atrás apenas dos Estados Unidos e a utilização do sêmen congelado no país vem expandido a cada dia. O índice de prenhez por ciclo, com sêmen equino congelado é variável e oscila entre 25 e 40%. Adicionalmente, sabe-se que o sêmen de alguns garanhões apresenta baixa viabilidade após o descongelamento. A primeira prenhez obtida com sêmen equino congelado foi relatada há cinco décadas. Segundo Cazalez, 2020, é muito difícil recomendar uma dose inseminante padrão para sêmen congelado em equinos. A maioria dos estudos científicos não consegue controlar o efeito de outros fatores "de confusão" como método de processo, fator égua, fator garanhão, técnica de inseminação etc., tornando difícil uma comparação crítica dos mesmos. Rigby et al. (2001) obtiveram taxas de prenhez similares ao se comparar a inseminação artificial profunda em corno uterino com endoscópio e pipeta flexível.(AU)

In the last fifteen years, equine breeding has been a prominent activity with significant growth in Brazil and in the world. Brazil is the second country in the world that most uses equine semen transport, second only to the United States, and the use of frozen semen in the country is expanding every day. The pregnancy rate per cycle with frozen equine semen is variable and ranges from 25 to 40%. Additionally, it is known that the semen of some stallions has low viability after thawing. The first pregnancy obtained with frozen equine semen was reported five decades ago. According to Cazalez, 2020, it is very difficult to recommend a standard insemination dose for frozen semen in horses. Most scientific studies cannot control for the effect of other "confounding" factors such as processing method, mare factor, stallion factor, insemination technique, etc., making it difficult to critically compare them. Rigby et al. (2001) obtained similar pregnancy rates when comparing deep artificial insemination in the uterine horn with an endoscope and flexible pipette.(AU)

Effect of short-term artificial light and transvaginal progesterone device on first ovulation in late transitional mares.

In study I, plasma progesterone concentrations were evaluated in anoestrous mares that received an intravaginal progesterone release device (IPRD) for 10 days. Mares were divided into 3 groups based on the dosage of progesterone (0 g, n=3; 1.38 g, n=5; and 1.9 g, n=5). No statistical differences were found in plasma progesterone concentrations between the two doses tested. In study II, the effects of a protocol based on a short program of artificial light combined with an IPRD containing 1.38 g of progesterone on oestrous behaviour and onset of ovulation were evaluated. IPRDs were inserted into 31 late transitional mares (10 days of treatment). The mares were divided into a control group (n=9, IPRD with 0 g of progesterone) and two treatment groups (T1, n=10, IPRD with 0 g of progesterone and artificial light; T2, n=12, IPRD with 1.38 g of progesterone and artificial light). The percentages of mares in heat within the first 14 days after treatment were 100%, 70%, and 100% in the control, T1, and T2 groups, respectively (P=0.097), and their ovulation rates were 44%, 60%, and 100%, respectively (P≤0.01). In conclusion, a protocol based on artificial light and an IPRD containing 1.38 g of progesterone for 10 days could be considered to advance the first ovulation of the year in late transitional mares, as it ensures a higher rate of ovulation within the first 14 days after treatment.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons.

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

Abstract This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

Aspartate aminotransferase and gamma glutamyl transferase levels in mares with miscarriage and healthy pregnancies

Background: Hormonal and physiological changes during pregnancy period have significant effects on animals' metabolisms. The purpose of the present study is to evaluate the variations of aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT) levels according to different gestation trimesters of the pregnant mares to assess changes of embryonic losses and abortions. Materials, Methods & Results: Blood samples from 49 thoroughbred mares were analyzed during this study. Age ratio of the mares is 5-18 years and their body condition score (BCS; score 1 to 9) varies between 5 and 6. A total of 28 mares had given birth to healthy foals at the end of a healthy gestation period (Group C), whereas 11 mares had embryonic losses (Group E) and 10 mares had late period abortions (Group A). Following the confirmation of pregnancy, one blood sample per gestation trimester were taken (14-16 days of pregnancy for 1st trimester; 180 days for 2nd trimester, 270 days for 3rd trimester). Early embryonic losses (loss of a 16-25 days embryo) were observed in 6 of 11 mares in Group E and the 5 of 11 mares had late period embryonic losses (loss of a 35-40 days embryo). In Group A, 6 mares had the abortion within 7th month and the remaining 4 mares had the abortion within the 8th month of pregnancy. Repeated Measures ANOVA, Kruskal-Wallis test and Mann-Whitney test were performed for statistical analysis, the mean AST level in Group C (n = 28) was higher during the 1st trimester in comparison to 2 following trimesters (respectively: P = 0.011 ; P = 0.01). Besides, no statistical difference was observed between 2nd and 3rd trimester regarding AST activation (P > 0.05). The mean GGT level in Group C was significantly decreased lower in the 3rd trimester compared to 1st and 2nd trimester (respectively: P = 0.007 ; P = 0.009). No statistical difference was observed between 2nd and 3rd trimester regarding GGT activation (P > 0.05). Among all groups (C, E, A) no significant difference was observed on AST levels (P > 0.05), nonetheless GGT levels had a significant rise (P = 0.039) in Group A in comparison to the 1st trimester levels of Group C. In Group A, there was a statistical decrease of AST during the 2nd trimester in comparison to the 1st trimester (P = 0.001), accompanied by a decrease of GGT activation during the 2nd trimester compared to the 1st trimester (P = 0.009). Discussion: The aminotransferases are catalisors that play an important role on the metabolism of amino acids and carbohydrates. Although serum AST levels were within the reference ranges during 3 trimesters in this study, serum AST levels were determined to be decreased in the 2nd and 3rd trimesters in healthy pregnant mares compared to the 1st trimester. It is thought that these results can be obtained due to the increase in metabolic needs during pregnancy. In this study, serum GGT levels remained within physiological limits with a tendency to decrease as the pregnancy advances, in accordance with previous study results. Serum GGT levels that are used as an indicator to liver damage may vary during the pregnancy as a result of increased metabolic load. It is thought that the increase of serum GGT levels in Group A might be related to the fetal (chromosome-related) issues that may result to pregnancy losses. As a result, it is considered that serum AST and GGT levels in mares might be valuable parameters that predict embryonic loss or abortus cases.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.(AU)

Intravaginal progesterone device (1. 9g) and estradiol benzoate for follicular control in the mare during spring and summer / [Implante intravaginal de progesterona (1, 9g) e benzoato de estradiol no controle folicular de éguas durante a primavera e o verão]

The objective of this study was to evaluate follicular growth and ovulatory rates in mares treated with an intravaginal progesterone device (P4) during the 10-day period, associated with the use of estradiol benzoate (EB). The results were compared during the transition period (ET) in the spring and the breeding season in the summer (ER). The variables were submitted to ANOVA (Tukey's test), considering P<0.05. No ovulation occurred during the permanence of the P4 implant in both experimental periods. The ovulatory rate in the ER was 100% (n = 8) and in the ET 62.5% (n = 5; P = 0.0547). Significant differences were observed (<0.001), in both periods, comparing follicular growth rates during the permanence of P4 device (ER: 1.33 ± 0.89mm/d; ET: 1.00 ± 0.81mm/d) to the period without P4 (ER: 3.63 ± 1.33 mm/d; ET: 3.31 ± 1.66 mm/d). The present study demonstrated applicability and efficiency of a hormonal protocol using P4 intravaginal device and EB for follicular control in mares, both during ET and ER.

O objetivo deste trabalho foi avaliar a taxa de crescimento folicular e a taxa ovulatória em éguas tratadas com dispositivo intravaginal de progesterona (P4) durante o período de 10 dias, associado à utilização de benzoato de estradiol (BE). Os resultados foram comparados durante o período de transição (ET) da primavera com a época de reprodução no verão (ER). As variáveis foram submetidas à ANOVA (teste de Tukey), considerando-se P<0,05. Nenhuma ovulação ocorreu durante a permanência do dispositivo de P4 em ambos os períodos experimentais. A taxa ovulatória na ER foi de 100% (n = 8) e na ET, de 62,5% (n=5; P=0,0547). Diferença significativas (<0,001) foram observadas, em ambos os períodos experimentais, comparando as taxas de crescimento folicular durante a permanência da P4 (ER: 1,33 ± 0,89mm/d; ET: 1,00 ± 0,81mm/d) com o período sem P4 (ER: 3,63 ± 1,33mm/d; ET: 3,31 ± 1,66mm/d). O presente estudo demonstrou aplicabilidade e eficiência do protocolo hormonal utilizando dispositivo intravaginal de P4 e BE para controle folicular de éguas, tanto na ET quanto na ER.

Electrocardiographic aspects of singleton pregnancy and neonatal period in American Miniature horse breed

Background: During pregnancy, cardiovascular adaptations occur in order to meet maternal demands and adequate supportfor fetal development, but they are still unclear in the equine species, especially in the American Miniature horse breed.The main hemodynamic changes that occur during pregnancy are increased heart rate, cardiac output, and blood volume.It is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition,so the objective of this study was to evaluate the effect of pregnancy on electrocardiographic (ECG) parameters in maresand also of age in newborns foals of American Miniature horse breed.Materials, Methods & Results: Ten American Miniature Horse mares, between 7 and 19 years old (12.14 ± 4.05 years),116.85 ± 24.09 kg of body weight were used in the experiment. All these mares were pluriparous, with 5.9 ± 3.5 of births,minimum of 2, and maximum of 12 foaling times. They were maintained in common social group in an indoor house stablewith straw bed, with access to an outdoor paddock for several h per day. Twice a day they were fed with hay. Mineral supplements and water were available ad libitum. The ECG were obtained in 10 pregnant mares and in 10 neonates. All femaleswere examined at a representative time of each trimester of pregnancy, at 30, 210, 300 days before and 21 days after delivery.Neonates were examined on different times: first 24 h after delivery, weekly on the 7th, 14th, 21st, 28th and 35th days of age.The ECG parameters considered were the heart rate and rhythm, duration and intervals (P, PR, QRS, QT, T) and amplitude(P, R, S, T) of ECG waves. The mean of pregnancy duration was 319.4 ± 4.97 days. Heart Rate (HR) varied between 51 to59 bpm during pregnancy and 56 bpm on the 21st day after delivery. Comparing the clinical parameters of pregnant mares,non-pregnant mares and foal a difference was found for HR, Respiration Rate (RR) and...(AU)

Electrocardiographic aspects of singleton pregnancy and neonatal period in American Miniature horse breed

Background: During pregnancy, cardiovascular adaptations occur in order to meet maternal demands and adequate supportfor fetal development, but they are still unclear in the equine species, especially in the American Miniature horse breed.The main hemodynamic changes that occur during pregnancy are increased heart rate, cardiac output, and blood volume.It is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition,so the objective of this study was to evaluate the effect of pregnancy on electrocardiographic (ECG) parameters in maresand also of age in newborns foals of American Miniature horse breed.Materials, Methods & Results: Ten American Miniature Horse mares, between 7 and 19 years old (12.14 ± 4.05 years),116.85 ± 24.09 kg of body weight were used in the experiment. All these mares were pluriparous, with 5.9 ± 3.5 of births,minimum of 2, and maximum of 12 foaling times. They were maintained in common social group in an indoor house stablewith straw bed, with access to an outdoor paddock for several h per day. Twice a day they were fed with hay. Mineral supplements and water were available ad libitum. The ECG were obtained in 10 pregnant mares and in 10 neonates. All femaleswere examined at a representative time of each trimester of pregnancy, at 30, 210, 300 days before and 21 days after delivery.Neonates were examined on different times: first 24 h after delivery, weekly on the 7th, 14th, 21st, 28th and 35th days of age.The ECG parameters considered were the heart rate and rhythm, duration and intervals (P, PR, QRS, QT, T) and amplitude(P, R, S, T) of ECG waves. The mean of pregnancy duration was 319.4 ± 4.97 days. Heart Rate (HR) varied between 51 to59 bpm during pregnancy and 56 bpm on the 21st day after delivery. Comparing the clinical parameters of pregnant mares,non-pregnant mares and foal a difference was found for HR, Respiration Rate (RR) and...

Dexmedetomidine and Bupivacaine Association in Caudal Epidural Injection in Mares.

The objective of the study was to compare the effects of caudal epidural bupivacaine and dexmedetomidine (DEX) combination, with bupivacaine or DEX plain for perineal analgesia in mares. Six healthy saddle mares weighing 330-370 kg and aged 10-15 years were used in this study. Each mare was assigned to receive three treatments: 0.04 mg/kg 0.25% bupivacaine (BP), 2 µg/kg DEX (DX), or 0.02 mg/kg bupivacaine and 1 µg/kg DEX (BPDX). The order of treatments was randomized. All drugs were injected into the caudal epidural space (Co1-Co2) through a 16-G Tuohy epidural needle. After the epidural injections, heart rate, respiratory rate, arterial blood pressures (systolic, diastolic, and mean), and rectal temperature were measured at 5, 10, 15, 30, 60, 90, and 120 minutes, and after this time, every 60 minutes until the end of the experiments. A subjective score system was used to assess analgesia, behavioral and motor blockade at the same time points. The BPDX treatment produced analgesic action with twice the duration (200 minutes) of the BP treatment (97 minutes), but with an analgesic duration shorter than the DX treatment (240 minutes) in the regions of the tail, perineum, and upper hind limbs in mares. All treatments showed mild motor blockade. No behavioral changes were observed in any of the animals. There was hemodynamic stability without significant changes in respiratory rate for all treatments. Epidural analgesia using DEX alone or the combination of DEX and bupivacaine may be an option for painful obstetric and gynecological procedures in mares.

Foals developmental orthopedic disease associated with metabolic and biometric characterization of pregnant overweight crioulo mares

Background: Musculoskeletal changes in growing foals can be linked to metabolic disorders which affect the cartilage metabolism associated of obesity during the late gestation of the mares, negatively affecting the athletic performance of the otherwise prospective foals. High basal insulin levels can be associated with increased weight and obesity of the mares, altering the supply of the glucose to the fetus and the production of IGF-1, which plays an important role in the endochondral cartilage metabolism. The present study aims to describe the association of metabolic and biometric alterations in overweight Criollo mares with IGF-1 levels and the presence of articular and physeal lesions in their foals. Materials, Methods & Results: A prospective and observational cohort study was conducted using the foals and the overweight mares at field conditions. Twenty-eight foals and their overweight mothers were utilized. The foals’ biometric and metabolic features as weight and height; glucose, total cholesterol, cholesterol HDL, triglycerides, basal insulin, leptin, glucose, total T4 and IGF-1 were analyzed, from the birth until the weaning period around sixth month of life of it. All the foals, at the weaning period, were submitted to the radiograph examination of the tarsal joints and the metacarpal-phalangeal joints to evaluate signs of lesions and the possible distal metacarpal physeal changes, respectively. The mares’ biometric and metabolic features as weight, height and fat tail-head deposition; basal insulin, leptin, glucose, total cholesterol, cholesterol HDL and triglycerides were analyzed at the final period of gestation. The basal insulin levels of the foals at the second, fourth and sixth month of life were 9.87 ± 1.82 µUI/mL, 9.13 ± 1.94 µUI/mL, 9.39 ± 2.54 µUI/mL. The IGF-1 levels of the foals at the second, third, fourth, fifth and sixth...

Transition period produces changes in blood and body composition in mares / Período de transição produz alterações na composição do sangue e do corpo em éguas

Clinical and metabolic evaluation is necessary for the monitoring of pregnant and lactating mares, as they reflect the health of the animal. The body condition of the mare is an indicator of reproductive efficiency. The study aimed to determine the possible variations in body and metabolic condition in Mangalarga Marchador mares during the transition period. Forty-eight mares distributed in two groups were used: Maintenance Group (MG), composed of non-pregnant and non-lactating mares, and Transition Group (TG), formed by pregnant mares and who after delivery became lactating. Analyzes were performed in the times T-60, T-30 and T-15 before delivery, first six hours (T0) after delivery and T15, T30 and T60 days after delivery. MG was evaluated only at one time (T-60). Body weight and fat-free mass differed (P<0.05) between the groups. The percentage of fat was lower in MG. Mares had a higher fat percentage in TG at T-60 and T-30 times. There was a difference (P<0.05) in the amount of cholesterol between MG and TG (T0, T15 and T30). Triglycerides were different between the groups. TG showed higher concentrations of non-esterified fatty acids (P<0.05). There was a higher amount of glucose in TG (delivery and lactation) when compared to mares in MG. Changes in body condition and metabolic constituents occurred in the animals resulting from physiological adaptations of the transition period. The energetic components are the most affected from the transition period, with intense fat mobilization to supply the body demands.(AU)

Avaliações clínicas e metabólicas são necessárias para o monitoramento de éguas gestantes e lactantes, pois refletem a saúde do animal. A condição corporal da égua pode ser um indicador da eficiência reprodutiva. O estudo objetivou determinar as possíveis variações na condição corporal e metabólica em éguas Mangalarga Marchador durante o período de transição. Foram utilizadas 48 éguas distribuídas em dois grupos: Grupo em Manutenção (GM) composto por éguas não gestantes e não lactantes; Grupo em Transição (GT) formado por éguas gestantes e que após o parto tornaram-se lactantes. As análises foram realizadas nos tempos T-60, T-30 e T-15 antes do parto, primeiras seis horas (T0) após o parto e T15, T30 e T60 dias após o parto. O GM foi avaliado apenas uma vez (T-60). O peso corporal e a massa livre de gordura diferiram (P<0,05) entre os grupos. O percentual de gordura foi menor em GM. As éguas apresentaram maior porcentagem de gordura no GT no T-60 e no T-30. Houve diferença (P<0,05) na quantidade de colesterol entre GM e GT (T0, T15 e T30). Triglicérides foram diferentes entre os grupos. GT apresentou maiores concentrações de ácidos graxos não esterificados (P<0,05). Houve maior quantidade de glicose no GT (parto e lactação) quando comparada às éguas no GM. Mudanças na condição corporal e nos constituintes metabólicos ocorreram nos animais resultantes de adaptações fisiológicas do período de transição. Os componentes energéticos são os mais afetados neste período, existindo intensa mobilização de gordura para suprir demandas corporais.(AU)