Evaluation of embryo-foetal biometry and its correlation with parturition date in Toy Poodle bitches.

Estimating the parturition date in dogs is challenging due to their reproductive peculiarities that. Ultrasonographic examination serves as a tool for studying embryo/foetal biometry and estimating the time of parturition by measuring foetal and extra-foetal structures. However, due to reproductive differences among various dog breeds, such estimates may have a non-significant pattern, representing inaccuracies in the estimated date of birth. This study aimed to monitor pregnant Toy Poodle bitches and establish relationships between ultrasonographically measured foetal and extra-foetal dimensions and the remaining time until parturition. Eighteen pregnant Toy Poodle bitches were subjected to weekly ultrasonographic evaluations and measurements of the inner chorionic cavity diameter, craniocaudal length (CCL), biparietal diameter (BPD), diameter of the deep portion of diencephalo-telencephalic vesicle (DPTV), abdominal diameter, thorax diameter (TXD), placental thickness and the renal diameter (REND). These parameters were retrospectively correlated with the date of parturition and linear regressions were established between gestational measurements and days before parturition (DBP). All analyses were conducted using the Statistical Package for Social Sciences (IBM® SPSS®) program at a 5% significance level. The foetal measurements that showed a high correlation (r) and reliability (R2) with DBP were BPD [(DBP = [15.538 × BPD] - 39.756), r = .97 and R2 = .93], TXD [(DBP = [8.933 × TXD] - 32.487), r = .94 and R2 = .89], DPTV [(DBP = [34.580 × DPTV] - 39.403), r = .93 and R2 = .86] and REND [(DBP = [13.735 × REND] - 28.937), r = .91 and R2 = .82]. This statistically validates the application of these specific formulas to estimate the parturition date in Toy Poodle bitches.

In vivo embryo development in bitches inseminated laparoscopically after ovulation time estimated based on a single progesterone determination

Logistic and economical limitations are often the causes of dog owners not accurately monitoring the estrous cycle and the optimal insemination time. The aim of this study was to evaluate in vivo early embryonic development in bitches, after the analysis of sequential vaginal cytologies associated to single progesterone measurement and single laparoscopic insemination with high quality semen (fresh and with high spermatozoa concentration) or low-quality semen (frozen/thawed and with low spermatozoa concentration) at 48 h post- ovulation time predicted on a single progesterone measurement. Ten bitches were inseminated with 250 x 106 fresh spermatozoa (80% motility), and ten with 80 x 106 frozen/thawed spermatozoa (60% motility) in the cranial part of each uterine horn. Seven days later, ovariohysterectomy was performed and the oviducts and uterine horns and body were flushed to recover embryos and unfertilized oocytes. In 80% of the bitches inseminated with fresh and 50% of bitches inseminated with frozen/thawed semen, embryos at 2 to 8 cells stage were recovered mostly from the, oviducts. This study indicates that pregnancies can be obtained with a single laparoscopic intrauterine insemination after single serum progesterone measurement, although with a low number of embryos. This result should be taken into account in case economic or logistic restrictions that affect the possibility of owners to plan an accurate monitoring of the optimal breeding time using fresh and frozen semen.(AU)

Manejo de neonatos caninos prematuros / Management of premature neonatal puppies

Dentre as mais importantes causas de morbidade neonatal na prematuridade, destacam-se os distúrbios respiratórios, complicações infecciosas, instabilidade crítica da termorregulação, inabilidade para homeostase energética e falhas na transferência de imunidade passiva. Dentre os problemas de origem pulmonar intimamente relacionados à prematuridade, destaca-se a imaturidade pulmonar por deficiência de surfactante, evoluindo para diminuição da capacidade pulmonar, hipoxemia, hipercapnia e acidose. Os neonatos caninos prematuros apresentam baixa vitalidade, hipotermia, bradipnéia, irregularidade do padrão respiratório, reduzido tônus e responsividade neuro-muscular. As áreas do parênquima pulmonar para efetuar trocas gasosas são limitadas em filhotes prematuros, culminando em alterações do equilíbrio ácidobase. Além disto, os recém-nascidos prematuros apresentam instabilidade energética e falha de transferência de imunidade passiva. Como medida preventiva à morbidade do neonato prematuro, indicase a corticoterapia pré-natal 48 horas antes do parto em cadelas gestantes, induzindo a maturidade funcional do pulmão fetal, além de melhorar a vitalidade e evolução clínica neonatal. Ademais, a corticoterapia antenatal estimula a transferência placentária de imunoglobulinas e absorção de imunoglobulinas colostrais, bem como aumenta a capacidade glicogênica. Nos casos emergenciais, preconiza-se medidas intensivas aos recém-nascidos prematuros, as quais incluem: reanimação respiratória, controle da hipotermia, reposição glicêmica na hipoglicemia e controle imunológico da falha de transferência imune passiva.(AU)

Among the most important causes of neonatal morbidity in prematurity, respiratory disorders, infectious complications, critical instability of thermoregulation, inability for energy homeostasis and failures in the transfer of passive immunity stand out. Among the problems of pulmonary origin closely related to prematurity, pulmonary immaturity due to surfactant deficiency stands out, evolving to decreased lung capacity, hypoxemia, hypercapnia and acidosis. Premature canine neonates have low vitality, hypothermia, bradypnea, irregular breathing pattern, reduced tone and neuromuscular responsiveness. The areas of the lung parenchyma to carry out gas exchange are limited in premature pups, culminating in changes in acid-base balance. In addition, premature newborns have energetic instability and failure to transfer passive immunity. As a preventive measure against premature neonate morbidity, prenatal corticosteroid therapy is indicated 48 hours before delivery in pregnant bitches, inducing functional maturity of the fetal lung, in addition to improving neonatal vitality and clinical evolution. Furthermore, antenatal corticosteroid therapy stimulates the placental transfer of immunoglobulins and the absorption of colostral immunoglobulins, as well as increasing the glycogenic capacity. In emergency cases, intensive measures are recommended for premature newborns, which include: respiratory resuscitation, hypothermia control, glycemic replacement in hypoglycemia and immunological control of passive immune transfer failure.(AU)

Neonatal severity indicators in dogs / Indicadores de severidade neonatal em cães

Despite the increasing interest for canine neonatology many aspects of canine neonatology are still not completely studied and perinatal mortality rates are high. The identification of newborn puppies at high risk at birth/hospitalization is the main goal in advancing veterinary neonatology, as well as the improvement of newborn assessment protocols. The identification of at risk puppies should rely on objective indicators of severity, allowing a differentiated clinical assistance according to neonatal conditions and allowing canine perinatal mortality reduce. This paper presents and discuss the neonatal severity indicators presently useful in the dog, as demonstrated by the specific scientific literature. Among them, some can be used only at birth, others only during the subsequent neonatal period and some useful at both times. Despite the availability of some useful severity indicators, the development of severity score systems are considered necessary also in dogs as in humans.

Ultrasonography of the nuchal translucency of healthy and abnormal English Bulldog fetuses

The aim of this study was to measure the nuchal translucency (NT) of canine fetuses to establish reference values ​​for healthy gestational processes and to verify its effectiveness in the diagnosis of congenital abnormalities. On day 34 of gestation, the NT of three fetuses from each of the 26 English bulldog female dogs was measured. The first fetus was the one located immediately cranial to the bladder, the second was selected from the left side of the abdomen, and the third from the right side. The reference values for healthy animals were offset using descriptive statistics. The diagnostic ability of the test to identify fetal malformations was studied using receiver operating characteristic curve analysis. Of the 26 litters, only 18 had healthy fetuses, 4 had fetuses with anasarca, 3 had fetuses with abdominal wall defects, and 1 had both types of abnormalities. The NT was higher in canine fetuses that presented anasarca in the litter than in normal litters (1.8 ± 0.77 mm vs. 1.4 ± 0.48 mm; P = 0.0249), with a cut-off value of NT > 1.45 mm (sensitivity = 61.54%, specificity = 70.18%). NT greater than 1.45 mm seems to be a diagnostic tool for the identification of anasarca during gestation of bulldogs. Considering the unprecedented use of this parameter in canine species and the limitations found during the study, further studies will be needed in order to use it on clinical practice.(AU)

Estimated date of delivery in Chihuahua breed bitches, based on embryo-fetal biometry, assessed by ultrasonography EN

Due to the peculiarities of the reproductive cycle of the female dog, which makes it difficult to accurately ascertain the date of conception, it may be challenging to precisely estimate the gestational age in bitches. Using fetal measurements obtained by ultrasound, it is possible to estimate the gestational age in dogs; however, due to the differences in size of the various breeds, such estimates may have a significant standard deviation, which represents less accuracy when specifying the date of birth. The purpose of this study was to evaluate pregnant female Chihuahuas, establishing relations between the fetal dimensions measured by ultrasound and the remaining time until delivery. Using 13 pregnant female Chihuahuas, weekly ultrasound assessments and measurements were performed, of the inner chorionic cavity, cranial-caudal length, biparietal diameter, abdominal diameter and thoracic diameter. Such parameters were retroactively correlated to the date of delivery, and linear regressions were established between the gestational measurements and remaining days until delivery. The fetal measurement presenting the highest correlation (r = 0.99; P<0.0001) and reliability (R2 = 0.98, P<0.0001) with the probable date of delivery was the biparietal diameter, a measurement that can be easily and safely obtained and, when applying a specific formula (Y = -15.46X1 + 38.72), can accurately predict the date of delivery in Chihuahua female dogs.(AU)

Effects of the cryopreservation process on dog sperm integrity

Sperm cryopreservation has become an indispensable tool in reproductive biology. However, frozen/thawed semen has a short lifespan due to loss of sperm cell integrity. To better understand which sperm cell structures are compromised by the cryopreservation process and apoptosis markers, the sperm of five healthy mature dogs was analyzed in this study. Analysis was performed after collection, cooling, and thawing via computer assisted sperm analyzer (CASA) and evaluation of membrane fluidity and permeability, phosphatidylserine translocation (Annexin V), membrane integrity, mitochondrial membrane potential, membrane lipid peroxidation (LPO) and activity of the apoptotic markers caspases 3 and 7 by flow cytometry. Cryopreservation decreased total and progressive motility and the percentage of rapid sperm (P < 0.01). Damage to sperm cells was confirmed by Annexin V (P <0.01), indicating that capacitation-like changes were induced by the cryopreservation procedures. An increase in sperm membrane fluidity was also noted in frozen/thawed samples (P < 0.01). Plasma and acrosomal cell membranes were affected (P < 0.01), with decreases in the subpopulation displaying high membrane potential (P < 0.01). Membrane LPO was increased in thawed sperm compared to cooled sperm (P < 0.05) but was not different from that in fresh sperm. No differences were observed in caspase 3 and 7 activity after cooling, freezing, or thawing. In conclusion, total and progressive motility, plasma membrane integrity and mitochondrial membrane potential suffered from the deleterious effects caused by cryopreservation, unlike the activity of caspases that remained stable during the freezing process.(AU)

Effects of the cryopreservation process on dog sperm integrity

Sperm cryopreservation has become an indispensable tool in reproductive biology. However, frozen/thawed semen has a short lifespan due to loss of sperm cell integrity. To better understand which sperm cell structures are compromised by the cryopreservation process and apoptosis markers, the sperm of five healthy mature dogs was analyzed in this study. Analysis was performed after collection, cooling, and thawing via computer assisted sperm analyzer (CASA) and evaluation of membrane fluidity and permeability, phosphatidylserine translocation (Annexin V), membrane integrity, mitochondrial membrane potential, membrane lipid peroxidation (LPO) and activity of the apoptotic markers caspases 3 and 7 by flow cytometry. Cryopreservation decreased total and progressive motility and the percentage of rapid sperm (P < 0.01). Damage to sperm cells was confirmed by Annexin V (P <0.01), indicating that capacitation-like changes were induced by the cryopreservation procedures. An increase in sperm membrane fluidity was also noted in frozen/thawed samples (P < 0.01). Plasma and acrosomal cell membranes were affected (P < 0.01), with decreases in the subpopulation displaying high membrane potential (P < 0.01). Membrane LPO was increased in thawed sperm compared to cooled sperm (P < 0.05) but was not different from that in fresh sperm. No differences were observed in caspase 3 and 7 activity after cooling, freezing, or thawing. In conclusion, total and progressive motility, plasma membrane integrity and mitochondrial membrane potential suffered from the deleterious effects caused by cryopreservation, unlike the activity of caspases that remained stable during the freezing process.

Estimated date of delivery in Chihuahua breed bitches, based on embryo-fetal biometry, assessed by ultrasonography

Due to the peculiarities of the reproductive cycle of the female dog, which makes it difficult to accurately ascertain the date of conception, it may be challenging to precisely estimate the gestational age in bitches. Using fetal measurements obtained by ultrasound, it is possible to estimate the gestational age in dogs; however, due to the differences in size of the various breeds, such estimates may have a significant standard deviation, which represents less accuracy when specifying the date of birth. The purpose of this study was to evaluate pregnant female Chihuahuas, establishing relations between the fetal dimensions measured by ultrasound and the remaining time until delivery. Using 13 pregnant female Chihuahuas, weekly ultrasound assessments and measurements were performed, of the inner chorionic cavity, cranial-caudal length, biparietal diameter, abdominal diameter and thoracic diameter. Such parameters were retroactively correlated to the date of delivery, and linear regressions were established between the gestational measurements and remaining days until delivery. The fetal measurement presenting the highest correlation (r = 0.99; P<0.0001) and reliability (R2 = 0.98, P<0.0001) with the probable date of delivery was the biparietal diameter, a measurement that can be easily and safely obtained and, when applying a specific formula (Y = -15.46X1 + 38.72), can accurately predict the date of delivery in Chihuahua female dogs.

The timeline development of female canine germ cells.

During the sex differentiation, the primordial germ cells (PGCs) pass through a differentiation, becoming spermatogonial cells in males and oocytes in females. In this phase, there is difference in gene expression and differentiation potency between males and females. Specific cell markers have been essential in the PGC meiosis beginning and become oocyte cells. However, there are few studies about germline in domestic animals. The domestic dog (Canis lupus familiaris) is an interesting animal model to be used in the investigation about the mammal development because it has several biochemical and physiological similarities to humans. In addition, some additional investigations about dogs may contribute to a better understanding of the biology and genetic components, improving clinical veterinary and zoological sciences. Here, we elucidated by immunofluorescence and quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR), the dynamics of the expression of pluripotent (POU5F1 and NANOG) and germline (DDX4, DAZL and DPPA3) markers that are very important in the development of female canine germ cells during 35-50 days post-fertilization (dpf). The female canine germ cells were positive for pluripotent markers during middle developmental period. The number of DDX4, DAZL and DPPA3 cells increased along the germ cell maturation from 45 to 50 dpf. We provided an expression analysis of the pluripotent and germline markers in paraffin sections using the middle and later periods in female canine germ cells. The results can contribute the understanding about the timeline of each marker along the maturation of female canine germ cells. These results have a great significance to demonstrate the germ cell profile changes because it may allow the development of protocols about in vitro germ cell derivation.

Avanços da ultrassonografia gestacional em cadelas / Advances of gestational ultrasonography in bitches

A ultrassonografia pré-natal é um exame estabelecido para o diagnóstico e acompanhamento gestacional. Deve ser realizado de forma sistemática, categorizado em diferentes análises como a biometria fetal, organogênese, análise da viabilidade fetal e acompanhamento minucioso nos dias que antecedem o parto. Tudo isto é imprescindível para minimizar e prevenir perdas da ninhada, principalmente em fêmeas que necessitarão de intervenção cirúrgica. Recomendam-se exames ultrassonográficos seriados e em diferentes fases para análises específicas, sendo que nos dias pré-parto, a análise da aceleração e desaceleração da frequência cardíaca fetal em conjunto ou não com a avaliação do índice de resistividade da artéria (s) umbilical (is) é importantíssima para a tomada de decisões. As grandes inovações da ultrassonografia gestacional em cadelas se dão pela descoberta das variações da frequência cardíaca fetal correlacionadas às contrações uterinas no momento pré-parto, o maior detalhamento do desenvolvimento dos órgãos específicos da cavidade abdominal do feto e a descoberta da possibilidade da sexagem fetal intrauterina. Todos estes tópicos foram abordados nesse artigo de revisão.

The prenatal ultrasound examination is an established test for gestational diagnosis and follow-up. A systematic ultrasonographic exam way should be done, categorized in different analyzes such as fetal biometry, organogenesis, fetal viability analysis, and close monitoring in the days before delivery. All this is essential to minimize and prevent losses of the litter, especially in females that will require surgical intervention. Serial ultrasonographic examinations in different times are recommended for specific analyzes, and in the pre-delivery days, the analysis of fetal heart rate acceleration and deceleration together or not with the evaluation of the resistivity index of the umbilical artery (ies) is very important for decision-making. The great innovations of gestational ultrasonography in bitches are the discovery of fetal heart rate variations and correlations related to uterine contractions at the prepartum time, the greater detail of the development of specific organs of the fetal abdominal cavity and the discovery of the possibility of intrauterine fetal sexing. All of these topics were covered in this review article.

Avanços da ultrassonografia gestacional em cadelas / Advances of gestational ultrasonography in bitches

A ultrassonografia pré-natal é um exame estabelecido para o diagnóstico e acompanhamento gestacional. Deve ser realizado de forma sistemática, categorizado em diferentes análises como a biometria fetal, organogênese, análise da viabilidade fetal e acompanhamento minucioso nos dias que antecedem o parto. Tudo isto é imprescindível para minimizar e prevenir perdas da ninhada, principalmente em fêmeas que necessitarão de intervenção cirúrgica. Recomendam-se exames ultrassonográficos seriados e em diferentes fases para análises específicas, sendo que nos dias pré-parto, a análise da aceleração e desaceleração da frequência cardíaca fetal em conjunto ou não com a avaliação do índice de resistividade da artéria (s) umbilical (is) é importantíssima para a tomada de decisões. As grandes inovações da ultrassonografia gestacional em cadelas se dão pela descoberta das variações da frequência cardíaca fetal correlacionadas às contrações uterinas no momento pré-parto, o maior detalhamento do desenvolvimento dos órgãos específicos da cavidade abdominal do feto e a descoberta da possibilidade da sexagem fetal intrauterina. Todos estes tópicos foram abordados nesse artigo de revisão.(AU)

The prenatal ultrasound examination is an established test for gestational diagnosis and follow-up. A systematic ultrasonographic exam way should be done, categorized in different analyzes such as fetal biometry, organogenesis, fetal viability analysis, and close monitoring in the days before delivery. All this is essential to minimize and prevent losses of the litter, especially in females that will require surgical intervention. Serial ultrasonographic examinations in different times are recommended for specific analyzes, and in the pre-delivery days, the analysis of fetal heart rate acceleration and deceleration together or not with the evaluation of the resistivity index of the umbilical artery (ies) is very important for decision-making. The great innovations of gestational ultrasonography in bitches are the discovery of fetal heart rate variations and correlations related to uterine contractions at the prepartum time, the greater detail of the development of specific organs of the fetal abdominal cavity and the discovery of the possibility of intrauterine fetal sexing. All of these topics were covered in this review article.(AU)

Canine fetus immune system at late development

The immune system is mainly responsible for protecting the organism against agents that may interfere in its homeostasis. Thus, understand how this system develops and operates is very important, for create new therapies to assist this system in its operation, such as its failure. In domestic dogs, few studies show how actually occurs the development, maturation and functioning of the immune system. Therefore, this study demonstrates the development and possible activation of it on dog fetus from late gestational period by in situ and microscopic analyzes.(AU)

Canine fetus immune system at late development

The immune system is mainly responsible for protecting the organism against agents that may interfere in its homeostasis. Thus, understand how this system develops and operates is very important, for create new therapies to assist this system in its operation, such as its failure. In domestic dogs, few studies show how actually occurs the development, maturation and functioning of the immune system. Therefore, this study demonstrates the development and possible activation of it on dog fetus from late gestational period by in situ and microscopic analyzes.

Use of a GnRH synthetic analog (buserelin) for estrous induction in female dogs / Utilização de análogo sintético de GnRH (buserelina) na indução do estro em cadelas

The aim of this study was to evaluate the effectiveness of a GnRH synthetic analog, as an estrous inducer in female dogs when administered during the anestrous phase, and to evaluate the pregnancy rate achieved through natural copulation. For this purpose, ten female dogs of different breeds were used. The subjects received buserelin by intramuscular injections at a dose of 2,1mcg when female dogs weighed up to 10kg (Group 1) and of 4,2mcg when the dogs weighed above 10kg (Group 2). Of the ten subjects, only three presented estrus after a single injection of buserelin: two dogs from Group 1 and one dog from Group 2 on average 7±1.29 days. The remaining seven dogs were given a second dose of buserelin, equal to the first administration. Of these, three belonged to Group 1 and four to Group 2. Four of these dogs exhibited clinical signs of estrus within, on average 9±7.3 days from the second injection. The seven female dogs that did enter estrus were fertilized successfully through natural copulation. The administration of buserelin was effective in inducing estrus in female dogs during the anestrous phase, with a maximum of two administrations.(AU)

Objetivou-se avaliar a eficácia de um análogo sintético ao GnRH como indutor de estro em cadelas em anestro e a taxa de prenhez por meio de cópula natural. Para isso, foram utilizadas 10 fêmeas caninas de diferentes raças. Cadelas de até 10kg de peso (grupo 1) foram submetidas à administração de buserelina por via intramuscular, na dose de 2,1mcg, e cadelas acima de 10kg (grupo 2) foram submetidas à mesma medicação, porém na dose de 4,2mcg. Das fêmeas em anestro, apenas três apresentaram estro com apenas uma aplicação, sendo duas do grupo 1 e uma do grupo 2, em 7±1,29 dias, em média. Em sete cadelas foi administrada mais uma dose de buserelina; destas, quatro eram pertencentes ao grupo 2 e três eram do grupo 1. Os sinais de estro ocorreram, em média, após 9±2,73 dias da segunda aplicação. As sete cadelas que manifestaram estro foram fertilizadas por meio de cópula natural. A administração de buserelina é eficiente para a indução de estro, em cadelas em anestro, em, no máximo, duas aplicações.(AU)

Partial ablation of endometrial glands in dogs after exposure to progestin during the neonatal period

Bitches with uteri devoid of endometrial glands should be sterile, and consequently could contribute to the population control of dogs. Considering that an inadequate exposure of the female reproductive system to steroids can lead to the formation of the uterine gland knock-out (UGKO) phenotype in some species, the aim of this study was to evaluate the effect of serial applications of medroxyprogesterone acetate (MPA) from birth until the age of six months on the development of endometrial glands in bitches. For this purpose, 16 female mongrel dogs from different litters were distributed into either an MPA group (n = 8), animals treated with 10 mg kg sc (Promone-E®, Pfizer, Brasil) at 3-week intervals, from day one after birth until the age of six months, or a control group (n = 8), composed of animals that only received a 0.9% NaCl solution in place of MPA. At six months of age, ovariohysterectomy was performed and uterine horn samples were collected for histological and immunohistochemical examinations. The bitches from the MPA-treated group presented a 35% decrease in the number of endometrial glands, a larger diameter of the endometrial glands, a greater epithelial height, as well as a greater thickness of the uterine wall, endometrium, and myometrium. However, no significant differences were observed between the two groups in the expression of ER-α, ER-β, and PR on the surface epithelium and endometrial stroma. Therefore, the serial application of MPA from birth until the age of 6 months do not completely ablate the development of the endometrial glands in bitches, but impair it by 35%.(AU)

Partial ablation of endometrial glands in dogs after exposure to progestin during the neonatal period

Bitches with uteri devoid of endometrial glands should be sterile, and consequently could contribute to the population control of dogs. Considering that an inadequate exposure of the female reproductive system to steroids can lead to the formation of the uterine gland knock-out (UGKO) phenotype in some species, the aim of this study was to evaluate the effect of serial applications of medroxyprogesterone acetate (MPA) from birth until the age of six months on the development of endometrial glands in bitches. For this purpose, 16 female mongrel dogs from different litters were distributed into either an MPA group (n = 8), animals treated with 10 mg kg sc (Promone-E®, Pfizer, Brasil) at 3-week intervals, from day one after birth until the age of six months, or a control group (n = 8), composed of animals that only received a 0.9% NaCl solution in place of MPA. At six months of age, ovariohysterectomy was performed and uterine horn samples were collected for histological and immunohistochemical examinations. The bitches from the MPA-treated group presented a 35% decrease in the number of endometrial glands, a larger diameter of the endometrial glands, a greater epithelial height, as well as a greater thickness of the uterine wall, endometrium, and myometrium. However, no significant differences were observed between the two groups in the expression of ER-α, ER-β, and PR on the surface epithelium and endometrial stroma. Therefore, the serial application of MPA from birth until the age of 6 months do not completely ablate the development of the endometrial glands in bitches, but impair it by 35%.

Use of a GnRH synthetic analog (buserelin) for estrous induction in female dogs / Utilização de análogo sintético de GnRH (buserelina) na indução do estro em cadelas

The aim of this study was to evaluate the effectiveness of a GnRH synthetic analog, as an estrous inducer in female dogs when administered during the anestrous phase, and to evaluate the pregnancy rate achieved through natural copulation. For this purpose, ten female dogs of different breeds were used. The subjects received buserelin by intramuscular injections at a dose of 2,1mcg when female dogs weighed up to 10kg (Group 1) and of 4,2mcg when the dogs weighed above 10kg (Group 2). Of the ten subjects, only three presented estrus after a single injection of buserelin: two dogs from Group 1 and one dog from Group 2 on average 7±1.29 days. The remaining seven dogs were given a second dose of buserelin, equal to the first administration. Of these, three belonged to Group 1 and four to Group 2. Four of these dogs exhibited clinical signs of estrus within, on average 9±7.3 days from the second injection. The seven female dogs that did enter estrus were fertilized successfully through natural copulation. The administration of buserelin was effective in inducing estrus in female dogs during the anestrous phase, with a maximum of two administrations.(AU)

Objetivou-se avaliar a eficácia de um análogo sintético ao GnRH como indutor de estro em cadelas em anestro e a taxa de prenhez por meio de cópula natural. Para isso, foram utilizadas 10 fêmeas caninas de diferentes raças. Cadelas de até 10kg de peso (grupo 1) foram submetidas à administração de buserelina por via intramuscular, na dose de 2,1mcg, e cadelas acima de 10kg (grupo 2) foram submetidas à mesma medicação, porém na dose de 4,2mcg. Das fêmeas em anestro, apenas três apresentaram estro com apenas uma aplicação, sendo duas do grupo 1 e uma do grupo 2, em 7±1,29 dias, em média. Em sete cadelas foi administrada mais uma dose de buserelina; destas, quatro eram pertencentes ao grupo 2 e três eram do grupo 1. Os sinais de estro ocorreram, em média, após 9±2,73 dias da segunda aplicação. As sete cadelas que manifestaram estro foram fertilizadas por meio de cópula natural. A administração de buserelina é eficiente para a indução de estro, em cadelas em anestro, em, no máximo, duas aplicações.(AU)

Effect of dietary supplementation with omega-3 and -6 on fresh and frozen/thawed sperm quality of dogs / Efeito da suplementação na dieta com ômega-3 e -6 sobre a qualidade do sêmen fresco e congelado de cães

For years, fatty acids have been recommended as a dietary supplement to improve canine hair. For animal reproduction, supplementation with omegas has been used to increase the reproductive efficiency and conception rate, but few studies have been conducted in dogs. The aim of this study was to evaluate the effects of daily dietary supplementation with omega-3 and -6 on the quality of fresh and frozen/thawed semen in canines. Semen was collected from seven dogs and evaluated for sperm motility, vigor, concentration, and morphology. The 17-week study included 119 ejaculates and was divided according to oral supplementation with omega-3 and -6: M1 (1st-5th week) or pre-supplementation; M2 (6th-9th week) and M3 (10th-13th week) or during supplementation; and M4 (14th-17th week) or post-supplementation. After analysis, the semen was frozen and then revaluated both immediately and 30 minutes (at 37 C) after thawing. Supplementation with omegas increased sperm motility, vigor, and concentration; however, supplementation had no influence on semen freezability. In addition, there was no improvement in sperm motility after supplementation when the thawed cells were maintained at 37 C for 30 minutes. We concluded that dietary supplementation with omega-3 and -6 for 4 to 8 weeks can improve the quality of fresh semen, although it has no effect on the freezability of canine semen.(AU)

Os ácidos graxos têm sido recomendados há anos como suplemento dietético para a melhora do pelo canino. Na área de reprodução animal, a suplementação com ômega tem sido usada para aumentar a eficiência reprodutiva e a taxa de concepção em muitas espécies, mas poucos estudos foram conduzidos em cães. Então, o objetivo deste estudo foi avaliar os efeitos da suplementação dietética diária com ômega-3 e -6 sobre a qualidade do sêmen fresco e congelado de cães. Os ejaculados foram colhidos de 7 cães e avaliados quanto a motilidade espermática, vigor, concentração e morfologia. O estudo foi dividido de acordo com os períodos de suplementação oral com omegas-3 e -6, no qual M1 (1ª-5ª semana) foi considerado o período pré-suplementação, M2 (6ª-9ª semana) e M3 (10ª-13ª semana) período de suplementação e M4 (14ª-17ª semana) pós-suplementação, totalizando 17 semanas de estudo (119 ejaculados). Após a análise, o sêmen foi congelado e reavaliado imediatamente e 30 minutos após a descongelação (mantidas a 37º C). A suplementação resultou em aumento da motilidade espermática, vigor e concentração do sêmen fresco; no entanto, não houve influência na congelabilidade do sêmen. Além disso, não houve aumento da motilidade dos espermatozoides após a suplementação, quando as células descongeladas foram mantidas a 37 C, durante 30 minutos. Concluiu-se que a suplementação dietética com omegas-3 e -6, durante 4 a 8 semanas melhora os parâmetros do sêmen fresco de cães, embora não há nenhum efeito sobre a qualidade espermática após a congelação.(AU)

Practical use of hormones in small animal reproduction / Uso clínico de hormônios na repodução de pequenos animais

The abortifacient efficacy of prostaglandin F2alpha products (PGF) involves induction of luteolysis,stimulation of uterine contraction and cervical dilation. PGF will induce luteolysis and depress progesterone (P4)concentrations to nearly non-detectable levels very easily after day 25 or 30 following just a 4-5 day course oftreatment. PGF can be used also earlier in pregnancy provided that the onset of cytological diestrus is timedprecisely and treatment course is longer than 5 days. With late abortion, the treatment must be continued untilverification of efficacy by ultrasound as partial abortion of litters can occur. Other uses of PGF includeshortening of diestrus in bitches, emptying the uterine content and improving semen quality in dogs. Antiprolactinagents include dopamine agonists (bromocriptine or cabergoline), and serotonin antagonists(metergoline). Anti-prolactin drugs can be used to control pseudopregnancy, induce abortion and the resumptionof estrus. Antiemetic (metoclopramide and domperidone) and antipsychotic drugs (chlorpromazine andsulpiride) have prolactin release properties which are widely documented in human medicine; their clinicalefficacy in the treatment of agalactia or hypogalactia is anecdotally reported also in bitches and queens.Aglepristone saturates P4 receptors causing abortion when administered at the dose of 10 mg/kg twice 24 hoursapart. The early administration of aglepristone at 0 to 25 days after mating is approximately 99% effective inprevention of pregnancy; however, care should be taken when using it without having assayed serum P4 or afterday 35 of pregnancy. Aglepristone can be used for several other purposes among which induction of parturitionand treatment of feline mammary hypertrophy. The clinical use of other hormonal drugs such as estrogens andsympatho-mimetics for conditions such as urinary incontinence and retrograde ejaculation is briefly discussed.