Effect of the performance, calving date and lactation period on the probability of pregnancy in beef cows

Determining what and how much each environmental factor affects pregnancy is crucial to the sustainability and management of beef cow herds. The study evaluated through logistic regression the effect of environmental variables on the increase or reduction in the pregnancy rate of beef cows. The average pregnancy rate in the cows was 73 %, with an average age for the herd of 3.7 years. An increase in age of one year represented a 30 % increase in pregnancy, while a reduction of one year reduced the odds of pregnancy in the cows by 23 %. During the lactation period, an extra seven days' lactation reduced the odds of pregnancy by 12 %. For every seven days that weaning was brought forward, the cows' pregnancy odds increased by 14 %. An increase of 0.1 kg in average daily gain represented an increase of 17 % and 15 % in the odds of pregnancy during the first 60 days post-partum and 60 days to the end of the reproductive period. On the other hand, the loss of 0.1 kg in average daily gain resulted in a 14 % and 13 % reduction in the cows' pregnancy odds, respectively. Factors such as age, the precocity of calving in the calving season, the time the calf remains with the cow and better performance in cows between calving and the end of the mating are strategies that increase the chances of pregnancy in beef cows.(AU)

Changes in expression levels of Nod-like receptors in the spleen of ewes

Nucleotide-binding oligomerization domain receptors (NOD-like receptors, NLRs) have critical effects on interfaces of the immune and reproductive systems, and the spleen plays a key role in both innate and adaptive immune functions. It is hypothesized that NLR family participates in maternal splenic immune regulation during early pregnancy in sheep. In this study, maternal spleens were collected on day 16 of the estrous cycle, and days 13, 16 and 25 of gestation (n = 6 for each group) in ewes. Expression of NLR family, including NOD1, NOD2, class II transactivator (CIITA), NLR family apoptosis inhibitory protein (NAIP), nucleotide-binding oligomerization domain, Leucine rich repeat and Pyrin domain containing 1 (NLRP1), NLRP3 and NLRP7, was analyzed using quantitative real-time PCR, Western blot and immunohistochemistry analysis. The results revealed that expression levels of NOD1, NOD2, CIITA and NLRP3 were downregulated at days 13 and 16 of pregnancy, but expression of NLRP3 was increased at day 25 of pregnancy. In addition, expression values of NAIP and NLRP7 mRNA and proteins were improved at days 16 and 25 of pregnancy, and NLRP1 was peaked at days 13 and 16 of pregnancy in the maternal spleen. Furthermore, NOD2 and NLRP7 proteins were limited to the capsule, trabeculae and splenic cords. In summary, early pregnancy changes expression of NLR family in the maternal spleen, which may be related with the maternal splenic immunomodulation during early pregnancy in sheep.(AU)

Impact of high-fat diet consumption during prolonged period of pregnancy on placenta structures and umbilical vascular growth in goats

This study aimed to verify the impact of high-fat diet consumption for a prolonged period on oxidative stress, fetal growth, umbilical vascular system, and placental structures in pregnant goats. Twenty-two pregnant goats were grouped into the control diet (n= 11) and fat diet (n = 11). Flaxseed meal was added to the fat diet, replacing the corn grain of concentrate, from gestational day 100 to delivery date. Diets were isonitrogenous and isoenergetic, differing in fat content (2.8% vs. 6.3% dry matter). The fat group showed higher feed intake and total plasma lipid levels than the control group (P < 0.001). No difference was found in placentome, and umbilical vascular development. Fat diet-fed goats exhibited a lower systolic peak in the umbilical artery. At delivery, placental traits were similar with the exception of the cotyledon width (P = 0.0075), which was smaller in the fat group and cotyledon surface (P = 0.0047) for multiple pregnancy of fat diet. Cotyledonary epithelium showed more intense staining of lipid droplets and a greater area for lipofuscin staining in the fat group compared to control group (P < 0.001). The mean live weight of the kids was lower in the fat group in the first week after delivery than in control group. Thus, in goats, the continuous administration of a high-fat diet during pregnancy does not appear to modify the fetal-maternal vascular structures but has an impact on a part of the placental structure; therefore, its use must be carefully evaluated.(AU)

Cetose subclínica e seu impacto no desempenho reprodutivo de vacas leiteiras: revisão de literatura / Subclinical ketosis and its impact on the reproductive performance of dairy cows: literature review

A cetose, conhecida também como acetonemia, é um distúrbio metabólico que afeta principalmente vacas leiteiras de alta produção. A elevação anormal de corpos cetônicos nos tecidos e fluidos corporais do animal ocorre devido a um déficit de energia. A quantidade de alimento/nutrientes ingeridos não é suficiente para suprir a demanda corporal do mesmo, assim como a eficiência reprodutiva que está diretamente ligada à saúde, condição corporal e sua capacidade de produção. Animais de alta produção possuem um desafio muito grande de aumentar a produção a cada lactação, com isso, estão susceptíveis a mudanças metabólicas, entre elas a cetose, clínica ou subclínica. Tal enfermidade ocorre devido a uma má adaptação metabólica do animal a sua nova condição de lactante. A elevada incidência de doenças uterinas no pós-parto de vacas leiteiras é responsável por inúmeros prejuízos para a atividade, principalmente pela redução da eficiência reprodutiva das vacas acometidas por infecções. Contudo, visto que a cetose subclínica prevalece nos rebanhos leiteiros de alta produção, o objetivo desta revisão de literatura é apresentar a patogenia e os efeitos que esse distúrbio metabólico têm sobre a reprodução das vacas de aptidão leiteira no após o parto, utilizando de indicadores como taxa de prenhez, taxa de concepção, retorno a ciclicidade, intervalo entre partos e intervalo entre parto e estro.(AU)

Ketosis, also known as acetonemia, is a metabolic disorder that primarily affects high-yielding dairy cows. The abnormal elevation of ketone bodies in the animal's tissues and body fluids occurs due to an energy deficit. The amount of food/nutrients ingested are not enough to supply the body's demand, as well as the reproductive efficiency that is directly linked to health, body condition and its production capacity. High production animals have a very big challenge to increase production with each lactation, therefore, they are susceptible to metabolic changes, including clinical or subclinical ketosis. Such a disease occurs due to a poor metabolic adaptation of the animal to its new lactating condition. The high incidence of uterine diseases in the postpartum period of dairy cows is responsible for numerous losses to the activity, mainly for the reduction of the reproductive efficiency of cows affected by infections. However, since subclinical ketosis prevails in high production dairy herds, the objective of this literature review is to present the pathogenesis and the effects that this metabolic disorder has on the reproduction of dairy cows in the postpartum period, using indicators such as pregnancy rate, conception rate, return to cyclicity, calving interval and calving-estrus interval.(AU)

Maternal and fetal ultrasonography, vulvar temperature and vaginal mucous impedance for the prediction of parturition in Saanen does

The aim of this study was to evaluate and correlate modifications of vaginal mucous impedance, vulvar temperature and ultrasonographic measurements (echobiometric parameters) to parturition in pregnant Saanen does. 30 does were selected for the study and submitted to an estrus synchronization protocol and natural mating. The females were evaluated daily from Day 143 of pregnancy to parturition. For the sonographic evaluations, the following structures were measured: biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length, kidney height, cardiac area, placentome length, cervical measurement and fetal heart rate; by means of two different approaches: transrectal and transabdominal, using a 7.5 MHz linear transducer. The vaginal mucous impedance was assessed using an electric estrous detector and vulvar temperature was measured using a non-contact infrared thermometer. Statistical analysis was performed using the R-project software and the significance level was set at 5% for all tests. 25 Saanen does became pregnant, resulting in 80.33% pregnancy rate. Fetal heart rate was negatively correlated to the hours to parturition (p<0,001; r-Pearson= -0,451), as well as vaginal temperature (p= 0,001; r-Pearson= -0,275), while cervical thickness was positively correlated to hours to parturition (p<0,001; r-Pearson= 0,490). The echobiometric parameters (biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length and height, cardiac area, placentome length), as well as vaginal mucous impedance did not vary throughout the timepoints of evaluation and did not correlate to the moment of parturition. It was concluded that the parameters of fetal heartbeat, vaginal temperature and cervical effacement in the last week of pregnancy provide valuable information regarding the proximity of parturition.(AU)

Prohibition of hormones in animal reproduction: what to expect and what to do?

As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. The development of Fixed-Time Artificial Insemination (FTAI) protocols at the end of the 20th century has increased exponentially the number of animals inseminated over the last 20 years. The main reasons for this growth were the possibility of obtaining acceptable pregnancy rates without heat detection and, above all, the induction of cyclicity in suckled cows in postpartum anestrus and prepubertal heifers at the beginning of the breeding season. Most FTAI treatments in South America have been based on the use of progesterone (P4) releasing devices and estradiol to synchronize both follicular wave emergence and ovulation, with pregnancy rates ranging from 40 to 60%. These protocols are implemented on a regular basis, allowing producers access to high-quality genetics, and increasing the overall pregnancy rates during the breeding season. In addition, it provided the professionals involved in these programs with a new source of income and the diversification of their practices into activities other than their usual clinical work. Many of these practices are now apparently at risk from restrictions on the use of estradiol by the European Union (EU) and other countries. However, the development of alternative protocols based on GnRH, with P4 devices and eCG and other new products that are not in the market yet will allow us to adapt to the new times that are coming. Logically, the challenge has already been raised and we must learn to use alternative protocols to try to continue increasing the use of this technology in beef and dairy herds. The objective of the present review is to describe the main aspects of banning estradiol in livestock production, the negative impacts on reproductive efficiency, and to present some alternative FTAI protocols for dairy and beef cattle.(AU)

Milk allergy in jersey cows: first report in Brazil / Auto alergia ao leite em vaca jersey: primeiro relato no Brasil / Alergia a la leche de auto en vaca jersey: primer reporte en Brasil

Allergy to milk is the only auto-allergic disease in cattle. It is characterized by the retention and absorption of milk itself, making milk proteins, especially alpha casein, have access to the bloodstream, resulting in a type I hypersensitivity. The purpose of this report is to describe a case of auto-allergic disease in cattle. Here we report the case of a four-year-old Jersey female bovine, which was pregnant and weighing 400Kg. The animal was being treated at (hidden for revision)and had a history of an acute allergic reaction. Its owner reported sudden onset of skin lesions, salivation, and difficulty breathing. As the animal was participating in an agricultural exhibition, it was not being milked to generate mammary gland engorgement (milk retention). Inphysical examination findings wherein there is presence of multifocal urticarial papules and plaques, mainly on the sides and right and left flanks, besides the absence of pruritus, edema in mucocutaneous regions of the upper and lower eyelids of the right and left eyes, submandibular edema, excessive salivation, inspiratory dyspnea with half-open mouth breathing, respiratory distress, apathy, cough, tachycardia tachypnea, ruminal hypomotility and increased volume of the mammary gland, characterizing milk retention. Clinical suspicion was milk allergy with anaphylactic reaction (type I hypersensitivity). Treatment was based on promethazine administration (1mg/kg; IV) and immediate full milking of the mammary gland. After 12 h of treatment, clinical respiratory signs resolved, and after 24 h, skin changes resolved completely. Based on clinical signs and treatment success, the clinical suspicion of milk allergy causing anaphylactic reaction (type I hypersensitivity) was confirmed.(AU)

A alergia ao leite é a única doença auto-alérgica em bovinos. Caracteriza-se pela retenção e absorção do próprio leite, fazendo com que as proteínas do leite, principalmente a alfa caseína, tenham acesso à corrente sanguínea, resultando em uma hipersensibilidade do tipo I. O objetivo deste relato é descrever um caso de doença autoalérgica em bovinos. Relatamos o caso de uma fêmea bovina da raça Jersey, com quatro anos de idade, prenhe e pesando 400Kg. O animal estava em tratamento (oculto para revisão)e tinha histórico de reação alérgica aguda. Proprietário relatou aparecimento súbito de lesões na pele, salivação e dificuldade respiratória. Oanimal estava participando de uma exposição agrícola, e não estava sendo ordenhado para gerar ingurgitamento da glândula mamária (retenção de leite). No exame físico identificou-sepápulas e placas urticariformes multifocais, principalmente nas laterais e flancos direito e esquerdo, ausência de prurido, edema em regiões mucocutâneas das pálpebras superior e inferior dos olhos direito e esquerdo, edema submandibular, salivação excessiva, dispneia inspiratória com respiração de boca entreaberta, desconforto respiratório, apatia, tosse, taquicardia, taquipneia, hipomotilidade ruminal e aumento do volume da glândula mamária, caracterizando retenção de leite. A suspeita clínica foi alergia ao leite com reação anafilática (hipersensibilidade tipo I). O tratamento baseou-se na administração de prometazina (1mg/kg; IV) e ordenha completa imediata da glândula mamária. Após 12 h de tratamento, os sinais clínicos respiratórios foram resolvidos e, após 24 h, as alterações cutâneas desapareceram completamente. Com base nos sinais clínicos e no sucesso do tratamento, confirmou-sea suspeita de alergia ao leite causando reação anafilática (hipersensibilidade tipo I).(AU)

La alergia a la leche es la única enfermedad autoalérgica en el ganado bovino. Se caracteriza por la retención y absorción de la propia leche, provocando que las proteínas de la leche, especialmente la alfa caseína, tengan acceso al torrente sanguíneo, dando lugar a una hipersensibilidad tipo I. El objetivo de este reporte es describir un caso de enfermedad autoalérgica en bovinos. Presentamos el caso de una vaca Jersey hembra de cuatro años, gestante y de 400 kg de peso. El animal estaba siendo atendido en el (oculto para revision)y tenía antecedentes de reacción alérgica aguda. Propietario refirió aparición repentina de lesiones en la piel, salivación y dificultad respiratoria. Como el animal participaba en una exhibición agrícola, no estaba siendo ordeñado para generar congestión de la glándula mamaria (retención de leche). En examen físico en los que se observan pápulas y placas urticariales multifocales, principalmente en costados y flancos derecho e izquierdo, además de ausencia de prurito, edema en las regiones mucocutáneas de los párpados superior e inferior del lado derecho e ojos izquierdos, edema submandibular, salivación excesiva, disnea inspiratoria con respiración con la boca abierta, dificultad respiratoria, apatía, tos, taquicardia (frecuencia cardíaca 88 latidos/minuto), taquipnea (100 movimientos/minuto), normotermia (39,0°C), hipomotilidad ruminal (2 movimientos ruminales/5 minutos) y aumento de volumen de la glándula mamaria, caracterizando la retención de leche. La sospecha clínica fue alergia a la leche con reacción anafiláctica (hipersensibilidad tipo I). El tratamiento se basó en la administración de prometazina (1 mg/kg; IV) y ordeño completo inmediato de la glándula mamaria. Después de 12 h de tratamiento, los signos clínicos respiratorios se resolvieron y, después de 24 h, los cambios en la piel desaparecieron por completo. Sobre la base de los signos clínicos y el éxito del tratamiento, se confirmó la sospecha clínica de alergia a la leche que causaba una reacción anafiláctica (hipersensibilidad tipo I).(AU)

Relação entre a capacitação espermática e a fertilidade de sêmen criopreservado de bovinos / Relationship between sperm capacitation and fertility in bovine cryopreserved semen

A qualidade do sêmen criopreservado, utilizado na inseminação artificial em tempo fixo (IATF) em bovinos, é um dos principais fatores que impactam sobre a fertilidade, e está relacionada à capacidade de produção espermática dos touros, à criotolerância dos espermatozoides e aos critérios técnicos do processo de criopreservação adotados. Neste sentido, devemos destacar a importância do controle de qualidade das partidas de sêmen antes de serem liberadas para uso na IATF. Nos últimos anos várias técnicas vêm sendo desenvolvidas para avaliar com mais acurácia as partidas de sêmen e evitar o uso daquelas que possam resultar em prejuízos na fertilidade, mas mesmo assim, tem se notado alta variabilidade na taxa de prenhez entre touros e entre partidas de sêmen. Esta divergência se deve ao fato da habilidade fértil do espermatozoide ser multifatorial, ou seja, dependente de diversas características estruturais, morfofuncionais e moleculares. Ademais, os eventos que permitem os espermatozoides passarem por capacitação espermática, um pré-requisito para a fertilidade, têm intrigado os pesquisadores em vista da complexidade dos processos envolvidos e dos efeitos deletérios da criopreservação espermática. Esta revisão tem por objetivo compilar estudos que mostrem a relação entre a capacitação espermática e a fertilidade do sêmen bovino criopreservado, levando em consideração as técnicas de avaliação e os resultados até o momento.(AU)

The quality of cryopreserved semen, used in fixed-time artificial insemination (FTAI) in cattle, is one of the main factors that impact fertility and is related to the sperm production capacity of bulls, sperm cryotolerance, and the technical criteria for cryopreservation. In this sense, we must highlight the importance of quality control of semen batches before commercialization for the FTAI. In recent years, several techniques have progressed to more accurately evaluate semen batches and avoid using those that may result in impaired fertility. However, we still notice a high variability in the pregnancy rate between bulls and between semen batches. This divergence is due to the multifactorial sperm-fertilizing ability, i.e., it depends on several structural, morphofunctional, and molecular characteristics. In addition, the events that allow sperm to undergo sperm capacitation, a prerequisite for fertility, have intrigued researchers due to the complexity of the processes involved and the adverse effects of sperm cryopreservation. This review aims to compile studies that show the relationship between sperm capacitation and fertility in cryopreserved bovine semen, considering the evaluation techniques and results to date.(AU)

Nutracêuticos no desempenho reprodutivo de garanhões / Nutraceuticals on the stallion breeding performance

O termo nutracêutico vem se tornando comum na reprodução animal e descreve produtos derivados dos alimentos, que podem fornecer benefícios adicionais a saúde, além dos valores básicos encontrados na dieta. Entre os vários nutracêuticos utilizados na reprodução, temos o ômega-3, ômega-6, vitaminas do complexo B, L-carnitina, ß-caroteno e antioxidantes. Portanto, objetivou-se apresentar as principais substâncias utilizadas como nutracêuticos e antioxidantes, seja utilizado de forma oral ou incorporado a diluentes de sêmen, com a finalidade de melhorar a qualidade seminal de garanhões, e consequentemente incrementar taxas de prenhez.(AU)

Nutraceuticals have become remarkably popular in animal reproduction and describe products derived from foods, which may provide additional health benefits, beyond the basic value found in diets. Among the main nutraceuticals used in male reproduction, there are omega-3 and 6, B-complex vitamins, L-carnitine, ß-carotene, and antioxidants. The aim of this review is to present the main substances used as nutraceuticals and antioxidants, either used orally or in combination with semen extenders, focusing on the improvement of seminal quality, and pregnancy rates.(AU)

Effective treatment of a case of pregnancy toxemia in sheep: case report / Tratamento eficaz de um caso de toxemia de gestação em ovelhas: relato de caso

Pregnancy toxemia has a high mortality rate and few cases with effective treatment are reported, especially when associated with secondary diseases. Therefore, the present work reports the case of a sheep, which was referred to the veterinary hospital of UFMG, in the last month of pregnancy, presenting apathy, hyporexia and sternal recumbency. After the diagnosis of pregnancy toxemia, the fetuses were removed while still alive, but did not survive. Monitoring was started with blood gas analysis, blood glucose assessments and laboratory tests. The results were consistent with liver damage, which was justified by the condition of lipolysis. Treatment consisted of electrolyte replacement plus 50% glucose and potassium chloride, along with administration of antibiotics (ceftiofur, 5mg/kg/SID/IM/7 days), flunixim meglumine (2.2mg/kg/SID/IM first day and 1.1mg/kg/SID/IM on the second and third days) and omeprazole (4mg/kg/SID/oral). The patient had secondarily clinical laminitis, which was treated with cryotherapy and anti-inflammatory drugs, in addition to mastitis, using a single dose of intramammary antibiotics. The work demonstrated the effectiveness of the treatment of pregnancy toxemia, when performed early and intensively, associated with daily clinical and laboratory monitoring of the animal.

A toxemia da prenhez possui alto índice de mortalidade, e poucos casos com tratamento eficaz são relatados, principalmente quando associados a doenças secundárias. Diante disso, o presente trabalho relata o caso de uma ovelha, que foi encaminhada ao hospital veterinário da UFMG, no último mês de gestação, apresentando apatia, hiporexia e decúbito esternal. Após o diagnóstico de toxemia da prenhez, os fetos foram retirados ainda vivos, porém não sobreviveram. Iniciou-se um monitoramento com análises hemogasométricas, avaliações de glicemia e exames laboratoriais. Os resultados foram condizentes com lesão hepática, a qual foi justificada pelo quadro de lipólise. O tratamento consistiu em reposição hidroeletrolítica associada à glicose 50% e a cloreto de potássio, juntamente com administração de antibióticos (ceftiofur, 5mg/kg/SID/IM/7 dias), flunixim meglumine (2,2mg/kg/SID/IM no primeiro dia e 1,1mg/kg/SID/IM no segundo e terceiro dias) e omeprazol (4mg/kg/SID/oral). A paciente apresentou secundariamente laminite clínica, a qual foi tratada com crioterapia e antinflamatórios, além de um quadro de mastite, sendo utilizado antibiótico intramamário em dose única. O trabalho demonstrou a eficácia do tratamento da toxemia da prenhez, quando realizado de forma precoce e intensiva, associado a um monitoramento clínico e laboratorial diário do animal.

Controles gestacionales y salud materno-neonatal en gatas / Gestational checking and maternal-neonatal health in cats

El primer punto a tener en cuenta es determinar si el estado de salud de la gata permite incluirla en un plan reproductivo y de ser así cuál es su probabilidad de distocia. Es así que se planifican 3 consultas: la primera durante el celo previo al servicio, la segunda 20 días después del día de los servicios momento en el que se realiza el diagnóstico de gestación y se evalúa el desarrollo de los conceptos gestados si la gata quedó preñada, y la tercera al día 50 de gestación en la cual se realiza un examen de salud y el control del número de fetos gestados mediante Rx. La evaluación del estado de salud de la madre y de los conceptos gestados, así como el desarrollo de los mismos permitirá estimar la fecha probable de parto, y programar la asistencia al parto o una cesárea con mínimos riesgos según sea el caso.(AU)

Pregnancy success in bitches - evaluation of interactions between artificial insemination method, serum progesterone concentration and vaginal cytology parameters

Background: The artificial insemination has become a well-established method in the breeding of bitches, and evaluation of the factors that may potentially affect pregnancy success is essential. For this reason, it is essential to evaluate the factors that may affect fertility of the bitch when artificial insemination is performed. Serum progesterone concentrations and vaginal cytology have been used to determine the time of ovulation and stage of the estrus cycle. This study aimed to evaluate the artificial insemination method, the serum progesterone concentration, the breed size, age, the whelping number, vaginal cytology parameters, and their interactions on pregnancy success in bitches. Materials, Methods & Results: A total of 607 bitches that had undergone reproductive consultation with the Mexican Canine Federation from January to December 2016 were enrolled in the present study and assigned to one of 2 artificial insemination methods (intravaginal and transcervical) using fresh semen. Determination of the estrus cycle phase and the time of Artificial insemination was based on vaginal cytology and serum progesterone concentrations. Bitches inseminated by the transcervical technique had a higher pregnancy rate with respect to females inseminated by the intravaginal technique (P < 0.05). Moreover, females with a serum progesterone concentration of 5-10 ng/mL had a greater probability (> 4 times) of getting pregnant than animals with lower or higher progesterone concentrations (P < 0.05). Bitches inseminated by the intravaginal technique and with serum progesterone concentrations >10 ng/mL had a considerable reduction in pregnancy (P < 0.05) compared with females with < 10 ng/mL serum progesterone or with bitches inseminated by the transcervical technique. Discusion: Serum progesterone concentration, the artificial insemination method, and superficial cells without a nucleus modified the pregnancy rate in bitches. Females inseminated by transcervical semen deposition had a higher pregnancy rate than females inseminated by the intravaginal technique. Using fresh or frozen-thawed semen produced a higher pregnancy rate in bitches inseminated by transcervical semen deposition than females inseminated by the intravaginal technique. Differences in the pregnancy rate between transcervical and intravaginal insemination could be associated with the correct semen disposition, the distance that the sperm must travel to reach the oocyte, as well as the number of sperm that reach the oviduct ampulla. Exist evidences that after ovulation, as progesterone rises, the cervix is closed, which may compromise the passage of the sperm deposited into the vagina. Therefore, it is likely that in females with a serum progesterone concentration > 10 ng/mL, the cervix was closed, compromising the ability of the sperm to access the oviduct. Thus, the use of intravaginal insemination should be done in bitches with a serum progesterone concentrations < 11 ng/mL to reduce the possibility of cervical closure and to increase the odds of pregnancy. It is well documented that the serum progesterone concentration and vaginal cytology parameters have a great influence on pregnancy success, and the results confirm these findings. In the present study, 96% of the bitches inseminated with a serum progesterone concentration of 5-10 ng/mL got pregnant and had higher odds of pregnancy than bitches with lower or higher serum progesterone concentrations.

Climate impacts on reproductive performance of Romanov sheep in the moderate climate

This study aimed to investigate the climatological impacts of air temperature, sunshine duration, and rain precipitation, in a moderate climate, on the reproductive performance of Romanov sheep in the continental part of Croatia, during two consecutive years (2019-2020). Our study included 549 matings with 520 successful conceptions at 5 Romanov sheep farms, and the fertility rate was 94.72%. The percentage of lambs delivered in winter was 53.27% (n = 277), in spring 20.19% (n = 105), in summer 14.23% (n = 74) and 12.31% in autumn (n = 64). According to percentile ranks and classification ratings, thermal conditions have been described as very warm (during 2019-2020), while precipitation conditions, expressed in percentiles, were wet (during 2019) but dry (during 2020) for this region. The peak of sexual activity was from mid-August until October in 2019 and from the end of August to November in 2020 for Romanov sheep in northwestern (NW) Croatia. A Kruskal-Wallis test showed a statistically significant difference in the number of pregnant ewes during the different mating seasons in the year (p < 0.001). Therefore, we can assume that air temperature, precipitation volume, and sunshine duration during the different seasons could impact the reproductive performance of Romanov sheep in a moderate climate.(AU)

Effect of growth and carcass traits on likelihood of early pregnancy in Nellore heifers raised at intensive nutritional plan

This study evaluated the influence of the quantitative traits measured by real-time ultrasound (adjusted longissimus muscle area [AdjLMA], adjusted rump fat thickness [AdjRFT], and adjusted marbling [AdjMAR]) as well as age at first breeding [AFB] and adjusted weight [AdjWeight], on the probability of occurrence of early pregnancy (EP) in 55 Nellore heifers, and also performed an economic analysis. All calves received supplementation in creep-feeding (ad libitum), and at weaning (average age= 210 ± 30 days; average weight= 241 ± 33 kg) until first breeding by artificial insemination (May to November) all heifers were managed in the same group (two paddocks of 25 ha each evenly covered with Urochloa Marandu Grass) and received protein-energy supplementation (1% of average BW per animal/day). The quantitative variables were collected immediately after timed artificial insemination (average age= 392 ± 27 days; average weight= 431.90 kg), and the pregnancy diagnosis was completed at 30 days following insemination. For economic analysis, two systems were compared (age at first breeding at 13 and 24 months). The greater adjusted weight on the first breeding increased the probability of occurrence of early pregnancy, while the greater adjusted longissimus muscle area reduced. In addition, intensive meat production systems provide greater economic return throughout cow-calf operation.(AU)

Reproductive disorders and reconception of beef cows subjected to timed artificial insemination / Perdas reprodutivas e reconcepção em fêmeas bovinas de corte submetidas a inseminação artificial em tempo fixo

The objective of this study was to evaluate gestational losses between 30 and 120 days of gestation and reconception in beef cows submitted to fixed-time artificial insemination (FTAI). The 18,462 information from the zootechnical file of animals submitted to FTAI in the period of the breeding season from November 2019 to April 2020 in the semiarid region of Minas Gerais were analyzed. The parameters evaluated were gestational loss, animal category, presence of the calf with the cow, body condition score (BCS) and final situation of the breeding season of the females that lost gestation after FTAI, the data were analyzed by Person's chi-square test (χ²) and Kruskal-Wallis test, with a significance level of 5% with use of the SPSS program. The final pregnancy rate was 58.52%. The loss rate between the first and second gestational diagnosis was 3.6%. Dependence was observed between the variables category and gestational loss (χ²= 12.374, p<0.05). The presence of the calf or not at the foot of the cow had no influence in relation to gestational loss (p>0.05). The difference in BSC between the categories was significant (p<0.05). Final situation was influenced (p<0.05) by animal category. Calving order and body condition score significantly influenced the gestational loss rate.

O objetivo deste estudo foi avaliar as perdas gestacionais entre 30 e 120 dias de gestação e reconcepção em vacas de corte submetidas à inseminação artificial em tempo fixo (IATF). Foram analisadas 18.462 informações do arquivo zootécnico de animais submetidos a IATF no período da estação de monta de novembro de 2019 a abril de 2020 na região do semiárido de Minas Gerais. Os parâmetros avaliados foram perda gestacional, categoria animal, presença do bezerro ao pé da vaca, escore de condição corporal (ECC) e situação final da estação de monta das fêmeas que perderam gestação após a IATF, os dados foram analisados pelo teste qui-quadrado de Person (χ²) e teste de Kruskal-Wallis, com nível de significância de 5% com uso do programa SPSS. A taxa de prenhez final foi de 58,52%. A taxa de perdas entre o primeiro e segundo diagnóstico gestacional foi de 3,6%. Observou-se dependência entre as variáveis categoria e perda gestacional (X²= 12,374, p<0,05). A presença do bezerro ou não ao pé da vaca, não teve influência em relação a perda gestacional (p>0,05). A diferença do ECC entre as categorias foi significativa (p<0,05). A situação final foi influenciada (p<0,05) pela categoria animal. A ordem de parição e o escore de condição corporal influenciam significativamente a taxa de perda gestacional.

In vitro sperm characteristics and in vivo fertility of sex-sorted and conventional semen in suckled Nelore cows at a traditional schedule for timed-AI with estrus detection / Características espermáticas in vitro e fertilidade in vivo de sêmen convencional e sexado em vacas Nelore pósparto submetidas à IATF tradicional com detecção de estro

The aim of this study was to assess in vitro sperm characteristics and pregnancies/AI (P/AI) of conventional and sex-sorted semen at timed-AI of suckled, multiparous Nelore cows. All cows (n=348) were submitted to a traditional estradiol/progesterone (P4)-based protocol. At 48h after P4-device removal, the estrous behavior was recorded, and AI was performed with conventional or sex-sorted semen from two bulls. The following sperm assessments were performed: CASA, Hyposmotic Test, sperm morphometry and chromatin structure by TB staining. P/AI were reduced (P<0.001) for sex-sorted compared to conventional semen in cows expressing estrus (27vs47%) or not (11vs.37%). Membrane integrity (Bull1: 30.3±9.6 vs. 52.3±12.4%, P=0.01; Bull2: 24.5±3.0 vs. 48.7±1.6%, P=0.006) and sperm concentration (Bulll: 23.2±0.6 vs. 43.0±0.8x10 sperm/mL, P<0.001; Bull2: 25.1+2.8 VS. 42.1±0.7x10 sperm/mL; P<0.001) were reduced in sex-sorted compared to conventional semen, for both bulls. Total and progressive motility were reduced in sex-sorted semen for Bull1 (TM: 49.7±15.9 vs. 94.9±1.9%, P=0.007; PM: 16.7±3.4 vs. 44.1±13.2%, P=0.009) and no differences were detected for Bull2 (TM: 45.0±17.5 vs. 68.2±19.1%, P=0.098; PM: 12.8±4.7 vs. 30.0±13.0%, P=0.065). Sperm ellipticity from sex-sorted was lower than conventional semen for Bull2 (0.306±0.01 vs. 0.342±0.02, P=0.02) and no difference was detected for Bull1 (0.332±0.01 vs. 0.330±0.01, P=0.55). Reduced in vivo fertility was observed for sex-sorted semen, regardless of estrous behavior. In vitro sperm quality of sex-sorted semen was compromised for both bulls, but differently affected for each sire.

O estudo teve como objetivo avaliar características espermáticas in vitro e a taxa de concepção (TC) de sêmen convencional e sexado em um programa de IATF tradicional de vacas Nelore pós-parto. Todas as vacas (n=348) foram submetidas ao mesmo protocolo de IATF à base de estradiol e de progesterona. Após 48 horas da retirada do implante, foi determinada a expressão de estro dos animais e a IA foi realizada com sêmen convencional e sexado de dois touros Angus. As seguintes características espermáticas foram avaliadas: análise computadorizada do sêmen, teste hiposmótico, morfometria espermática e estrutura cromatinica por meio da coloração com azul de toluidina. A TC foi menor (P<0,001) para sêmen sexado comparado ao convencional, em vacas que expressaram estro (27 vs. 47%) e que não apresentaram estro (11 vs. 37%). A integridade da membrana plasmática (Touro 1: 30,319,6 vs. 52,3+12,4%, P=0,010; Touro 2: 24,5+3,0 vs. 48,7±1,6%, P=0,006) e a concentração espermática (Touro 1: 23,2±0,6 vs. 43,0±0,8x10 sperm/mL, P<0,001; Touro 2: 25,1+2,8 vs. 42,1 +0,7x10'sperm/mL, P<0,001) foram menores no sêmen sexado comparado ao convencional, para ambos os touros. Motilidades total e progressiva foram menores no sêmen sexado comparado ao convencional para o Touro 1 (MT: 49,7±15,9 vs. 94,9±1,9%, P=0,007; MP: 16,7+3,4 vs. 44,1+13,2%, P=0,009), enquanto diferenças não foram detectadas no Touro 2 (MT: 45,0±17,5 vs. 68,2±19,1%, P=0,098; MP: 12,8±4,7 vs. 30,0±13,0%, P=0,065). Elipticidade espermática do sêmen sexado foi menor do que do sêmen convencional no Touro 2 (0,306±0,01 vs. 0,342±0,02, P=0,020), mas não houve diferença no Touro 1 (0,332±0,01 vs. 0,330±0,01, P=0,552). Reduzida fertilidade in vivo foi observada para o sêmen sexado em relação ao convencional, independentemente da expressão de cio das vacas. A qualidade seminal in vitro do sêmen sexado foi comprometida para ambos os touros, mas diferentemente afetada para cada reprodutor.

Efeitos da progesterona injetável em vacas de corte com diferentes escores de cio antes do início do protocolo de IATF / Effects of injectable progesterone in beef cows with different etrus scores before the start of the FTAI protocol / Efectos de la progesterona inyectable en vacas de carne con diferentes puntuaciones de estro antes del inicio del protocolo IATF

A IATF é uma biotecnologia da reprodução que permite o melhoramento genético dos rebanhos de corte, pois possibilita a sincronização da ovulação e realização da inseminação artificial sem necessidade de detecção do cio. O objetivo deste estudo, foi avaliar a eficiência da pré-sincronização com a utilização prévia de progesterona (P4) injetável, sua influência e efeitos na taxa de prenhez, por meio da realização de um protocolo de IATF em vacas de corte multíparas, em quatro fazendaslocalizadas no Mato Grosso do Sul-SP. Para o estudo foram utilizadas 396 vacas nelores, os animais de cada fazenda foram alocados em grupos distintos experimental e controle. Foram avaliadas 196 vacas pertencentes ao grupo controle, e 200 vacas tratadas com progesterona no total, sendo as fazendas descritas neste estudo como fazenda A, B, C e D. Dez dias antes do início do protocolo (D-10), foi aplicado progesterona injetável, via intramuscular em animais do mesmo lote, no D0 foi aplicado benzoato de estradiol e colocado o dispositivo intravaginal com liberação de progesterona, além da classificação dos animais que apresentavam ou não o corpo lúteo. No D8 o dispositivo foi retirado e aplicado uma dose de gonadotrofina coriônica equina, e cipionato de estradiol e de prostaglandina. A inseminação artificial em tempo fixo foi realizada no D10, com a utilização de sêmen de touros provados. O diagnóstico de gestação foi feito no D40, comparando os resultados das taxas de prenhez das vacas dos diferentes grupos, que foram tratadas ou não com progesterona de forma prévia ao protocolo. Sobre as taxas de prenhez dos animais tratados com progesterona, foram encontrados os resultados da fazenda A= 6,60%, fazenda B=10,80%, fazenda C= 3,90% e fazenda D= 3,70%, assim ficando evidente que essa biotecnologia da reprodução é lucrativa e contribui positivamente para a cadeia de produção de bovinos de corte. Baseado nos resultados, pode-se concluir que o uso da P4 (injetável) obteve êxito no índice de prenhez.(AU)

The IATF is a reproduction biotechnology that allows the genetic improvement of beef herds,as it allows the synchronization of ovulation and artificial insemination without the need for heat detection. The objective of this study was to evaluate the efficiency of pre-synchronization with the previous use of injectable progesterone (P4), its influence and effects on the pregnancy rate, through the performance of an IATF protocol in multiparous beef cows, in four farms located in Mato Grosso do Sul-SP. For the study, 396 Nelore cows were used, the animals from each farm were allocated into different experimental and control groups. A total of 196 cows belonging to the control group were evaluated, and 200 cows treated with progesterone in total, being the farms described in this study as farms A, B, C and D. Ten days before the beginning of the protocol (D-10), injectable progesterone was administered , intramuscularly in animals of the same batch, on D0 estradiol benzoate was applied and the intravaginal device was placed with progesterone release, in addition to the classification of animals that had or did not have the corpus luteum. On D8, the device was removed and a dose of equine chorionic gonadotropin, estradiol and prostaglandin cypionate was applied.Fixed-time artificial insemination was performed on D10, using semen from proven bulls. The pregnancy diagnosis was made on D40, comparing the results of the pregnancy rates of the cows of the different groups, which were treated or not with progesterone prior to the protocol. From the pregnancy rates of animals treated with progesterone, the results were found for farm A= 6.60%, farm B= 10.80%, farm C= 3.90% and farm D= 3.70%, thus becoming evident that this reproductive biotechnology is profitable and contributes positively to the beef cattle production chain. Based on the results, it can be concluded that the use of P4 (injectable) was successful in the pregnancy rate.(AU)

La IATF es una biotecnología de la reproducción que permite la mejora genética de rebaños de carne, ya que permite sincronizar la ovulación y la inseminación artificial sin necesidad de detección de celo. El objetivo de este estudio fue evaluar la eficiencia de la presincronización con el uso previo de progesterona inyectable (P4), su influencia y efectos en la tasa de preñez, mediante la realización de un protocoloIATF en vacas de carne multíparas, en cuatro fincas ubicadas en Mato Grosso do Sul-SP. Para el estudio se utilizaron 396 vacas Nelore, los animales de cada finca se distribuyeron en diferentes grupos experimentales y de control. Se evaluaron un total de 196 vacas pertenecientes al grupo control, y 200 vacas tratadas con progesterona en total, siendo las fincas descritas en este estudio como fincas A, B, C y D. Diez días antes del inicio del protocolo (D-10), se administró progesterona inyectable, por vía intramuscular en animales del mismo lote, sobre D0 se aplicó benzoato de estradiol y se colocó el dispositivo intravaginal con liberación de progesterona, además de la clasificación de animales que tenían o no cuerpo lúteo. El D8 se retiró el dispositivo y se aplicó una dosis de gonadotropina coriónica equina, estradiol y cipionato de prostaglandina. Se realizó inseminación artificial a tiempo fijo en D10, utilizando semen de toros probados. El diagnóstico de preñez se realizó el D40, comparando los resultados de las tasas de preñez de las vacas de los diferentes grupos, que fueron tratadas o no con progesterona previo al protocolo. A partir de las tasas de preñez de los animales tratados con progesterona se encontraron los resultados para la finca A= 6.60%, finca B= 10.80%, finca C= 3.90% y finca D= 3.70%, evidenciándose así que esta biotecnología reproductiva es rentable y contribuye positivamente a la cadena productiva del ganado vacuno de carne. Con base en los resultados, se puede concluir que el uso de P4 (inyectable) fue exitoso en la tasa de embarazo.(AU)

Estação do ano ao parto e o desempenho reprodutivo de vacas leiteiras mestiças / Season of the year at calving and reproductive performance of crossbred dairy cows

O objetivo deste trabalho foi avaliar os efeitos da estação do ano ao parto sobre a taxa de concepção à primeira inseminação pós-parto e o intervalo parto-concepção de vacas leiteiras mestiças. O estudo foi conduzido em sete fazendas localizadas em Ituiutaba/MG. O manejo reprodutivo foi realizado a cada 30 dias para avaliação ginecológica e diagnóstico de gestação. Na primeira cobertura pós-parto, as vacas detectadas em estro eram submetidas à inseminação artificial (IA) 12 horas após a detecção ou colocadas com touro (monta controlada ­ MC). As vacas não detectadas em estro até os 60 dias pós-parto eram submetidas à inseminação em tempo fixo (IATF). Os serviços subsequentes seguiam os critérios de cada fazenda. Foram avaliados 841 partos de 581 vacas ocorridos de janeiro de 2011 a junho de 2014. Os dados foram analisados pelo PROC GLIMMIX do SAS (p<0,05), sendo incluídos no modelo a fazenda, a estação do ano ao parto, o tipo da primeira inseminação pós-parto e possíveis interações. As vacas que receberam MC apresentaram taxa de concepção à primeira IA pós-parto maior do que as vacas submetidas à IA convencional e à IATF (p<0,001). Não foi detectada interação entre o tipo de serviço e a estação do ano ao parto (p=0,2989) na taxa de concepção. A estação do ano ao parto não interferiu na taxa de concepção à primeira IA pós-parto de vacas leiteiras mestiças (p=0,36). No entanto, vacas que pariram na primavera-verão tiveram esse intervalo maior em relação às que pariram no outono-inverno (p=0,0044). Desta forma, concluiu-se que vacas leiteiras mestiças cujos partos ocorrem nas estações mais quentes e úmidas do ano apresentam um comprometimento da eficiência reprodutiva subsequente.

The study aimed to evaluate the effects of the season of the year at calving on the conception rate at the first insemination post-partum and the calving-conception interval of crossbred dairy cows. The study was conducted on seven farms located in Ituiutaba/MG. The reproductive management was performed every 30 days for gynecologic evaluation and pregnancy diagnostic. At the first post-partum service, cows detected in estrus were submitted to artificial insemination (AI) 12 hours after estrus detection or bred by the sire (controlled breeding ­ CB). Cows that were not detected in estrus until 60 days after calving were submitted to timed artificial insemination (TAI). The subsequent services followed the criteria of each farm. A total of 841 parturitions from 581 cows occurred from January 2011 to June 2014 were evaluated. Data were analyzed by PROC GLIMMIX of SAS (p<0.05), including the farm, the season of the year at calving, the type of the first insemination post-partum and, possible interactions in the model. Cows submitted to CB presented a higher conception rate at first insemination post-partum than cows submitted to conventional AI and TAI (p<0.001). There was no interaction between the service type and the season of the year at calving (p=0.2989) on the conception rate. The season of the year at calving did not influence the conception rate at first insemination post-partum of crossbred dairy cows (p=0.36). However, cows that calved during spring-summer had a prolonged interval in relation to cows that calved during autumn-winter (p=0.0044). In conclusion, crossbred dairy cows whose calving occurs in the hottest and wettest seasons of the year show a subsequent impairment of their reproductive performance.

Aspectos morfofisiológicos e biotécnicas aplicadas à reprodução de novilhas bovinas e búfalas pré-púberes / Morphophysiological aspects and biotechnologies applied to the reproduction of prepubertal bovine and buffalo heifers

A puberdade corresponde ao momento da primeira ovulação, que culmina com o desenvolvimento final dos órgãos e estruturas envolvidas no controle neuro-endócrino reprodutivo. É um fenômeno multifatorial com grande impacto na vida produtiva das futuras matrizes e em sua eficiência econômica, ocorrendo muitas interações entre os fatores internos e externos. A idade da puberdade está relacionada ao peso corporal, que possui grandes efeitos da genética do animal e sua interação com o ambiente, especialmente a nutrição e interação social com machos. Algumas espécies, como os bubalinos, sofrem efeito de outros elementos ambientais, como a luminosidade e o fotoperíodo. A puberdade novilhas búfalas ou bovinas pode ser adiantada por meio do emprego de biotécnicas: indução da puberdade ou inseminação artificial em tempo fixo (IATF). Em ambas, os protocolos baseiam-se, principalmente, em aplicação de progestágeno associado com fonte de estradiol; mas a indução também pode ser realizada utilizando outros hormônios, como hormônio liberador de gonadotrofinas, prostaglandinas e gonadotrofina coriônica equina. No emprego da IATF, novilhas pré-púberes podem ser induzidas e inseminadas com outro protocolo de sincronização ou podem ser inseminadas com o mesmo protocolo de IATF, podendo aumentar as taxas de prenhez e diminuir os custos. Adiantando a puberdade, ocorre incremento na produção, melhorando a eficiência econômica da atividade pecuária.(AU)

Puberty corresponds to the moment of the first ovulation, which culminates in the final development of the organs and structures involved in the neuro-endocrine control of reproduction. It is a multifactorial phenomenon with a great impact on the productive life of future matrices and their economic efficiency, with many interactions between internal and external factors. The age of puberty is related to body weight, which has great effects on the animal's genetics and its interaction with the environment, especially nutrition and social interaction with males. Some species, such as buffalo, are affected by other environmental elements, such as luminosity and photoperiod. Puberty in buffaloes and bovine heifers can be advanced through the use of biotechniques: induction of puberty or timed artificial insemination (TAI). In both, the protocols are mainly based on the application of progestogen associated with a source of estradiol; but induction can also be performed using other hormones, such as gonadotropin-releasing hormone, prostaglandins and equine chorionic gonadotropin. In the employment of the TAI, prepubertal heifers can be induced and inseminated with another synchronization protocol or they can be inseminated with the same TAI protocol, which can increase pregnancy rates and decrease costs. Advancing puberty, there is an increase in production, improving the economic efficiency of livestock activity.(AU)

Ultrasound measurements of uterine height, horns diameter and presence of intraluminal fluid to investigate uterine involution in lactating sows housed in farrowing crates

The uterine involution of sows housed in farrowing crates was investigated during lactation using B-mode trans-abdominal ultrasonography. The objectives were to describe uterine involution, detect any delay or uterine disorders and assess possible associations between involution and subsequent reproductive performance. Three parameters were measured: uterine height (H), horns diameter (D) and the percentage of sows with intraluminal fluid (F). During lactation (3-4 weeks), H decreased from 11.0±1.6 the first week to 5.9±1.5 cm the last week (p<0.001), and D from 2.6±0.7 to 1.4±0.2 cm (p<0.001). Between days 1-7, H and D decreased significantly faster, i.e. respectively 0.38 cm (p<0.0001) and 0.20 cm (p<0.0001) per day than between days 22-28, i.e. respectively 0.02 cm (p=0.49) and 0.00 cm (p=0.75) per day. F decreased significantly (p<0.0001) from 78% at the beginning to 16% at the end of lactation. Between days 1-7, F decreased significantly (p<0.001) faster than during the last week of lactation (p=0.41). Between days 22-28, H of sows from parity ≥3 were significantly higher than those of sows from parity 1 and 2 (p=0.007). During that period, F was significantly higher in sows of higher parity. This effect of parity on F was significantly higher during the entire lactation period in sows of parity ≥6. Some sows were monitored after weaning. There was no significant relationship between the 3 parameters measured at the end of lactation and the subsequent performance. A small number of sows was suspected of endometritis (2%) and one case of fœtoplacental retention was detected. In conclusion, B-mode ultrasonography is a suitable tool to monitor uterine involution in lactating sows. When examination is conducted during the last week of lactation, it may help the farmer to verify whether uterine involution is complete, and to decide whether a sow should be either culled or maintained on farm.(AU)