Sêmen refrigerado ­ estado da arte em diferentes espécies / Chilled semen ­ state of the art in different species

Na atual conjuntura da criação artificial de bovinos e bubalinos, o material genético masculino de qualidade superior de reprodutores é explorado ao máximo possível através da inseminação artificial em tempo fixo de um grande número de fêmeas com apenas um único ejaculado. Para isso, é necessário um sêmen de boa qualidade que desempenhe um papel indispensável na melhoria das taxas de fertilidade, independente de qual tipo seja utilizado (fresco, refrigerado e congelado). Porém, o processo de congelação/descongelação causa uma série de injúrias aos espermatozoides, ocasionando resultados inferiores para percentuais de viabilidade espermática, motilidade, membrana plasmática e integridade acrossomal, potencial de membrana mitocondrial, cinemática do esperma, quando comparado ao sêmen refrigerado. Assim, o objetivo desta revisão é disseminar o conhecimento sobre o uso sêmen refrigerado na preservação de germoplasma de reprodutores bovinos e bubalinos para melhorar as taxas de concepção em propriedades. Para isso, serão abordados comentários sobre o armazenamento do sêmen refrigerado, com ênfase nas diferenças entre curvas de refrigeração, suas vantagens e desvantagens relativas para procedimentos de uso na IATF, identificando o método mais indicado por diversos autores, o estado atual da biotécnica, seus méritos e possibilidades futuras.(AU)

In the current conjuncture of the artificial creation of bovines and buffaloes, the male genetic material of superior quality of sires is exploited to the maximum possible through the fixed-time artificial insemination of a large number of females with only a single ejaculate. For this, a good quality semen is needed that plays an indispensable role in improving fertility rates, regardless of which type is used (fresh, chilled and frozen). However, the freezing/thawing process causes a series of injuries to spermatozoa, causing lower results for percentages of sperm viability, motility, plasma membrane and acrosomal integrity, mitochondrial membrane potential, sperm kinematics, when compared to refrigerated semen. Thus, the objective of this review is to disseminate knowledge about the use of chilled semen in the preservation of germplasm of bovine and buffalo breeders to improve conception rates in properties. For this, comments on the storage of refrigerated semen will be addressed, with emphasis on the differences between refrigeration curves, their relative advantages and disadvantages for procedures for use in FTAI, identifying the method most indicated by several authors, the current state of biotechnics, its future merits and possibilities.(AU)

Assisted Reproductive Technologies (ART) and genome editing to support a sustainable livestock

This article provides an overview of assisted reproductive technologies (ART) and genome engineering to improve livestock production systems for the contribution of global sustainability. Most ruminant production systems are conducted on grassland conditions, as is the case of South American countries that are leaders in meat and milk production worldwide with a well-established grass-feed livestock. These systems have many strengths from an environmental perspective and consumer preferences but requires certain improvements to enhance resource efficiency. Reproductive performance is one of the main challenges particularly in cow-calf operations that usually are conducted under adverse conditions and thus ART can make a great contribution. Fixed-time artificial insemination is applied in South America in large scale programs as 20 to 30% of cows receive this technology every year in each country, with greater calving rate and significant herd genetic gain occurred in this region. Sexed semen has also been increasingly implemented, enhancing resource efficiency by a) obtaining desired female replacement and improving animal welfare by avoiding newborn male sacrifice in dairy industry, or b) alternatively producing male calves for beef industry. In vitro embryo production has been massively applied, with this region showing the greatest number of embryos produced worldwide leading to significant improvement in herd genetics and productivity. Although the contribution of these technologies is considerable, further improvements will be required for a significant livestock transformation and novel biotechnologies such as genome editing are already available. Through the CRISPR/Cas-based system it is possible to enhance food yield and quality, avoid animal welfare concerns, overcome animal health threats, and control pests and invasive species harming food production. In summary, a significant enhancement in livestock productivity and resource efficiency can be made through reproductive technologies and genome editing, improving at the same time profitability for farmers, and global food security and sustainability.(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)

Recent advances in treatments for resynchronization of ovulation in small ruminants: a review

Hormonal methodologies to control small ruminants' estrous cycle are worldwide used and evolved, adjusting the application to the precise female physiological moments to enhance reproductive performance. The estrous cycle can be induced and/or synchronized, aiming for fixed-time artificial insemination, or based on estrus behavior signs for insemination, natural or guided mating. Successive protocols can be performed to resynchronize ovulation and increase reproductive outcomes in females that failed to conceive. These recently developed treatments aim to resynchronize the ovulation as earlier as non-pregnancy is detected. The present review aimed to summarize the recent advances and main findings regarding resynchronization protocols used in small ruminants. Lastly, we present future perspectives and new paths to be studied in the subject. The resynchronization treatment is still a growing field in small ruminant reproduction, nevertheless, some enhancements are found in the reproductive outcome, showing that such protocols can be successfully used in sheep and goat production.(AU)

Antral follicle count classification selects fertile heifers without influencing the carcass traits / A classificação da contagem folicular antral seleciona novilhas mais férteis sem influenciar as características da carcaça

This study aimed to evaluate the ovarian structure, estrus intensity, ultrasound carcass measurements, and pregnancy rate of Nelore breed heifers and cows in accordance with antral follicle counts (AFCs). We evaluated 503 heifers and 565 Nelore cows, with a mean age of 15.5±2.2 and 69.8±36.1 months, respectively, submitted to a fixed-time artificial insemination (FTAI) protocol. On day zero, all bovine females were examined using ultrasound to determine the AFC. The mean AFC of the heifers and cows were 20±8.6 and 22.5±8.4, respectively. The rib-eye area (REA) and fat thickness (FT) of the heifers (n = 119 for REA and n = 219 for FT) were measured using ultrasound imaging. The average conception rates at the first FTAI and at the end of the breeding season were 35.8% and 57.5%, respectively, for heifers and 45.1% and 78.9%, respectively, for cows. We demonstrated that the probability of pregnancy at the first FTAI and at the end of the breeding season for both young heifers and cows increased as the AFC decreased (P>0.001 and P=0.0123, respectively). FT and REA showed no correlation with AFC in heifers. The intensity of estrus expression was negatively correlated with AFC (−0.46; P<0.0001). In conclusion, Nelore heifers and cows with low AFC had a high probability of pregnancy during the entire breeding season. Thus, AFC can be used as a tool to select heifers with increased fertility without affecting carcass traits (REA and FT).

Este estudo teve como objetivo avaliar as estruturas ovarianas, intensidade do cio, medidas de carcaça por ultrassonografia e taxa de gestação de novilhas e vacas da raça Nelore com diferentes contagens de folículos antrais (CFA). Avaliamos 503 novilhas e 565 vacas Nelore, com idade média de 15,5 ± 2,2 e 69,8 ± 36,1 meses, respectivamente, submetidas a um protocolo de inseminação artificial em tempo fixo (IATF). No dia zero, todas as fêmeas foram examinadas por ultrassom para determinar a CFA. A CFA média das novilhas foi de 20 ± 8,6 e a das vacas foi de 22,5 ± 8,4 folículos. A área de olho de lombo (AOL) e a espessura de gordura (EG) das novilhas (n = 119 para AOL e n = 219 para EG) foram medidas utilizando imagens ultrassonográficas. As taxas médias de concepção na primeira IATF e no final da estação de monta foram de 35,8% e 57,5% e 45,1% e 78,9% para as novilhas e vacas, respectivamente. Demonstramos que a probabilidade de gestação na primeira IATF e no final da estação de monta, tanto para novilhas jovens quanto para vacas, foi maior quando a CFA era menor (P>0,001 e P=0,0123, respectivamente). A espessura da gordura e a AOL não mostraram nenhuma correlação com a CFA. A intensidade da expressão do cio foi negativamente correlacionada com o CFA (-0,46; P < 0,0001). Em conclusão, novilhas jovens e vacas da raça Nelore com menor CFA apresentam maior probabilidade de prenhez durante toda a estação de monta. Nenhuma relação entre a CFA e as características de carcaça foram observadas em novilhas Nelore. A CFA pode ser usada como uma ferramenta de seleção de novilhas com maior fertilidade sem influenciar as características de carcaça (AOL e EG).

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)

Farmacopuntura em protocolos de sincronização de estro em pequenos ruminantes / Pharmacopuncture in estrus synchronization protocols in small ruminants

O objetivo com essa revisão foi realizar o levantamento da produção científica disponível e articular saberes a respeito do uso da farmacopuntura associada à protocolos de sincronização de estro principalmente em caprinos e ovinos, como também, em outras espécies de interesse. Ao analisar as pesquisas realizadas nos últimos 10 anos com a utilização de subdoses hormonais associada à farmacopuntura em programas de inseminação artificial em tempo fixo (IATF), nota-se que a farmacopuntura vem se tornando uma ferramenta promissora para viabilizar a redução das doses hormonais administradas e potencializar o efeito do fármaco aplicado, o que eleva a eficiência dos programas de sincronização de estro/ovulação ao reduzir os custos desses protocolos. Além de diminuir o custo desses protocolos para os produtores, nosso grupo de pesquisa realizou uma série de estudos nessa área, visando a busca por protocolos com menores doses hormonais, o que consequentemente reduz a quantidade de resíduos produzidos e promove manejos mais sustentáveis. Baseado nas publicações, pode-se afirmar que a farmacopuntura apresenta resultados satisfatórios e coloca-se como uma via de aplicação de sub-doses ou micro-doses hormonais em protocolos de controle do ciclo estral em caprinos e ovinos, como também, para outras espécies domésticas.(AU)

The objective of this review was to compile information regarding the use of pharmacopuncture associated with estrus synchronization protocols, mainly in goats and sheep, as well as in other species of interest, with the aim of updating and providing information on the subject. When analyzing the research carried out in the last 10 years with the use of hormonal underdoses associated with pharmacopuncture in fixed-time AI programs, these have become a promising tool to enable the reduction of administered hormonal doses and to potentiate the effect of the applied drug, the that increases the efficiency of estrus/ovulation synchronization programs by reducing the costs of these protocols. In addition to reducing the cost of these protocols for producers, our research group carried out a series of studies in this area, aiming at the search for protocols with lower hormonal doses, less waste produced and more sustainable management. Based on the publications, it can be stated that pharmacopuncture presents satisfactory results and is a way of applying sub-doses or micro-doses of hormones in protocols for controlling the estrous cycle in goats and sheep, as well as for other domestic species.(AU)

Reproductive performance of single fixed-time inseminated sows with semen doses submitted to different semen storage times

This study aimed to evaluate the reproductive performance of sows submitted to single fixed-time insemination (SFTAI) using boars according to capacity for liquid in vitro semen preservation, type of extender, and storage time. Boars (n = 12) were classified into two groups based on progressive motility (PM) at 120 h of semen storage: low (PM - 64.5%) - and high-preservation (PM - 83.9%) capacity for semen storage. Weaned sows (n = 397, parity - 1 to 7) were inseminated (1.5×109 sperm cells) in a factorial design: two classes of boars (low- or high-preservation), two types of extenders (short- or long-term), and two semen storage times at insemination (24 or 72 h). An adapted triptorelin acetate protocol was used for SFTAI. Total sperm motility (TM) and PM at insemination were greater in high-preservation boars at 72 h compared with low-preservation boars at 24 or 72 h (P < 0.01). Short- or long-term extender did not affect (P ≥ 0.68) TM and PM in high-preservation boars; however, long-term extender improved these parameters in low-preservation boars (P < 0.01). Pregnancy and farrowing rates were not affected by groups (P > 0.05). Total piglets born (TPB) was reduced (P = 0.05) in low-preservation boars with 72 h of storage (13.6 ± 0.5) compared to high-preservation boars with semen stored for 24 or 72 h (15.2 ± 0.5 and 15.5 ± 0.5, respectively). The low-preservation boars reduced the TPB in sows submitted to SFTAI, and this reduction was greater using semen stored for 72 h.(AU)

Application of PGF2α at the moment of fixed-time artificial insemination in crossbred beef cows

Although studies have shown positive effects of gonadotropin releasing hormone (GnRH) or prostaglandin F2α (PGF2α) at the moment of fixed-time artificial insemination (FTAI) in the conception rate (CR) of cattle, its effects on treatments based on progesterone (P4) and estradiol benzoate (EB) is still not conclusive. The objective of this study was (1) to evaluate the effect of a PGF2α analogue at FTAI in the CR of crossbred beef cows submitted to a 11d FTAI protocol based on P4 and EB; and (2) to describe the CR between PGF2α-treated and control cows in different body condition scores (BCS) and parity categories. Crossbred (½ Nellore and ½ Angus) beef cows were submitted to a synchronization protocol and randomly assigned into 2 groups: Control (n = 163), at FTAI cows received 2 mL of saline solution as a placebo, and PGF2α (n = 163), at FTAI cows were treated with PGF2α analogue (10 mg of dinoprost tromethamine). Pregnancy diagnosis was performed 33d post-FTAI. Binary logistic regression model was used to analyze the effect of PGF2α treatment on CR. There was no difference in CR between PGF2α and control groups (P > 0.05; odds ratio (OR) = 0.92; confidence interval (CI) = 0.59-1.4). A greater CR was found in heifers (P = 0.0006, OR = 2.65, CI = 1.61 - 4.38) and multiparous (P = 0.0006, OR = 2.12, CI = 1.04 - 4.3) when compared to primiparous cows. Cows with low BCS (4; 9-point scale) showed lower CR when compared with moderate BCS (5-6; 9-point scale) (P < 0.05; OR = 0.10; CI = 0.06 - 0.18). There was no numerical difference on CR between PGF2α-treated and control cows in different BCS and parity categories. The results suggested that the CR in this study was not influenced by 10 mg PGF2α analogue at FTAI.(AU)

Reproductive performance of fixed-time artificial insemination in heifers supplemented with a homeopathic complex / Desempenho reprodutivo à inseminação artificial em tempo fixo em novilhas suplementadas com complexo homeopático

For this study, ½ blood Nelore × Aberdeen Angus heifers (n = 40; 14 months) were divided into two groups: control (n=20; 310 kg) and Pró-Cio (n=20; 304 kg). For Pró-Cio group, 20g of homeopathic product (Pró-cio®, Real H, Campo Grande, Brazil) was supplied together with corn eighteen days prior (D-18) to the beginning of the fixed-time artificial insemination protocol (FTAI). On D0, all females received an intravaginal P4 device and 2 mg BE. On D5, the AFC was assessed by ultrasound and blood was collected for AMH dosage. On D8, P4 device was removed; 300 IU eCG, 0.530 mg of cloprostenol sodium and 0.5 mg of EC were administered; an estrus-identifying adhesive was fixed at the tail insertion and the diameter of the dominant follicle (DF) was measured. On D10, all heifers were inseminated, estrus manifestation was assessed and the preovulatory follicle (POF) was measured. On D20, the CL area was measured and blood flow was assessed using Doppler ultrasound. Data were analyzed by Student, Mann-Whitney or Friedman test. The rates of heat expression, ovulation, and blood flow score with Doppler were analyzed using Fisher's exact test and pregnancy rate by binary logistic regression model (P ≤ 0.05). There was no difference in AFC or AMH dosage (P > 0.05). Pró-Cio group had greater diameters of the DF (9.94 ± 0.42 mm) and POF (11.61 ± 0.56 mm) than the controls (DF: 7.72 ± 0.34 mm and POF: 9.91 ± 0.37 mm), as well a larger CL area (3.26 ± 0.26 versus 2.35 ± 0.16 cm2) and a higher mean CL vascularization score (3.06 versus 2.26; P < 0.05). There was no significant difference (P > 0.05) between estrus manifestation or conception rate for control and Pró-Cio groups. Heifers supplemented with the homeopathic product showed larger follicular diameters at the end of the FTAI protocol and CL with better blood flow scores compared to the control group.

Para esse estudo, novilhas ½ sangue Nelore x Aberdeen Angus (n = 40; 14 meses) foram divididas em dois grupos: Controle (n = 20; 310 kg) e Pró-cio (n = 20; 304 kg). Para o grupo Pró-Cio, 20 g/animal de produto homeopático (Pró-cio®, Real H, Campo Grande, Brazil) foi fornecido juntamente com o milho dezoito dias antes (D-18) de inicar o protocolo de inseminaçãoa artificial em tempo-fixo (IATF). No D0, todas as fêmeas receberam um dispositivo intravaginal de P4 e 2 mg BE. No D5, avaliou-se a contagem de folículos antrais (CFA) por ultrassonografia e realizou-se coleta de sangue para dosagem de AMH. No D8, procedeu-se a retirada do dispositivo de P4; aplicação de 300 UI de eCG, 0,530 mg de cloprostenol sódico e 0,5 mg de CE; um adesivo identificador de estro foi fixado na inserção da cauda e foi feita a mensuração do diâmetro do folículo dominante (FD). No D10, todas as novilhas foram inseminadas, foi realizada a avaliação da manifestação de estro e mensuração do folículo pré-ovulatório (FPO). No D20, realizou-se mensuração da área e avaliação do fluxo sanguíneo do CL por ultrassonografia Doppler. Os dados foram analisados pelos testes de Student, Mann-Whitney ou Friedman. As taxas de expressão de estro, ovulação e escore de fluxo sanguíneo com Doppler foram analisadas usando o teste exato de Fisher e taxa de prenhez pelo modelo de regressão logística binária (p ≤ 0,05). Não houve diferença na CFA nem na dosagem de AMH (p > 0,05). O grupo PróCio apresentou maior diâmetro do FD (9,94 ± 0,42 mm) e FPO (11,61 ± 0,56 mm) em relação ao controle (FD: 7,72 ± 0,34 mm e FPO: 9,91 ± 0,37 mm), além de maior área do CL (3,26 ± 0,26 versus 2,35 ± 0,16 cm2; p < 0,05) e maior escore de vascularização médio do CL (3,06 versus 2,26; p < 0,05). Não houve diferença (p > 0,05) na taxa de manifestação de estro e nem na taxa de concepção entre os grupos Controle e Pró-Cio, respectivamente. Novilhas suplementadas com o produto homeopático apresentaram maiores diâmetros foliculares ao final do protocolo de IATF e CL com melhores escores de fluxo sanguíneo em relação ao grupo controle.

Comparison of hematological parameters between single and twin pregnancies in Dorper ewes during gestation, lambing, and postpartum / Comparação dos parâmetros hematológicos entre ovelhas Dorper de gestação simples e gemelar durante a prenhez, parto e pós-parto

ABSTRACT: The hematopoietic system changes during the pregnancy to carry fetal development and maternal needs. This study compared the hematological parameters between ewes with single and twin pregnancies during gestation, delivery, and postpartum. The experiment was conducted on 60 healthy pregnant Dorper ewes that were divided into two experimental groups: Group 1 (G1), with single pregnancies (n=30), and Group 2 (G2), with twin pregnancies (n=30). Blood samples were collected from all ewes at different times: immediately before fixed-time artificial insemination (AI); on day 30, 90, 120, 130, and 140 of pregnancy; immediately after delivery; and at 24h and 48h postpartum. Statistical analysis compared the two groups at different times (P<0.05). Mild, normocytic, and hypochromic anemia was detected in all ewes from AI time and throughout pregnancy from both groups, but did not prove to be of clinical relevance. In the peripartum stage (from the 140th day of pregnancy to 48h postpartum), the ewes with twin pregnancies (G2) exhibited higher erythrogram values and neutrophil:lymphocyte ratio than did ewes with single pregnancies (G1). This indicated a greater hematopoietic adaptation in the body during the development of two fetuses. Except for the eosinophil numbers, all leukogram parameters were influenced by pregnancy in a similar way in both groups, and was characterized mainly by leukocytosis with neutrophilia during peripartum due to the high presence of endogenous cortisol at delivery. Thus, these findings showed that pregnancy was a stressful physiological event that increased the leukocyte count with a slight alteration in the erythrogram of Dorper ewes.

RESUMO: O sistema hematopoiético sofre mudanças durante a gestação para atender o desenvolvimento fetal e as necessidades maternas. Este estudo comparou os parâmetros hematológicos entre ovelhas com gestação simples e gemelar durante a prenhez, parto e pós-parto. O estudo foi realizado em 60 ovelhas Dorper prenhes, saudáveis, divididas em dois grupos experimentais: Grupo 1 (G1) com gestação simples (n = 30); e Grupo 2 (G2) com gestação gemelar (n = 30). Amostras de sangue foram colhidos de todas as ovelhas em diferentes momentos: imediatamente antes da inseminação artificial em tempo fixo (IA); nos dias 30, 90, 120, 130 e 140 de gestação; imediatamente após o parto; e às 24h e 48h pós-parto. A análise estatística comparou os dois grupos nos diferentes momentos (P < 0,05). Anemia leve, normocítica e hipocrômica foi detectada desde a IA e ao longo da gestação, nas ovelhas de ambos os grupos, mas não houve relevância clínica. Na fase periparto (do 140º dia de gestação às 48h pós-parto), as ovelhas com gestação gemelar (G2) mostraram valores do eritrograma e proporção neutrófilos: linfócitos mais elevados do que as ovelhas com gestação simples (G1). Isso indicou maior adaptação hematopoiética da ovelha para o desenvolvimento de dois fetos. Com exceção do número de eosinófilos, todos os parâmetros do leucograma foram influenciados pela gestação de forma semelhante em ambos os grupos, e foi caracterizada principalmente por leucocitose com neutrofilia no periparto devido ao alto nível de cortisol endógeno no parto. Assim, os achados mostraram que a gestação foi um evento fisiológico estressante que aumentou a contagem de leucócitos com leve alteração no eritrograma de ovelhas Dorper.

Comparison of hematological parameters between single and twin pregnancies in Dorper ewes during gestation, lambing, and postpartum / Comparação dos parâmetros hematológicos entre ovelhas Dorper de gestação simples e gemelar durante a prenhez, parto e pós-parto

The hematopoietic system changes during the pregnancy to carry fetal development and maternal needs. This study compared the hematological parameters between ewes with single and twin pregnancies during gestation, delivery, and postpartum. The experiment was conducted on 60 healthy pregnant Dorper ewes that were divided into two experimental groups: Group 1 (G1), with single pregnancies (n=30), and Group 2 (G2), with twin pregnancies (n=30). Blood samples were collected from all ewes at different times: immediately before fixed-time artificial insemination (AI); on day 30, 90, 120, 130, and 140 of pregnancy; immediately after delivery; and at 24h and 48h postpartum. Statistical analysis compared the two groups at different times (P<0.05). Mild, normocytic, and hypochromic anemia was detected in all ewes from AI time and throughout pregnancy from both groups, but did not prove to be of clinical relevance. In the peripartum stage (from the 140th day of pregnancy to 48h postpartum), the ewes with twin pregnancies (G2) exhibited higher erythrogram values and neutrophil: lymphocyte ratio than did ewes with single pregnancies (G1). This indicated a greater hematopoietic adaptation in the body during the development of two fetuses. Except for the eosinophil numbers, all leukogram parameters were influenced by pregnancy in a similar way in both groups, and was characterized mainly by leukocytosis with neutrophilia during peripartum due to the high presence of endogenous cortisol at delivery. Thus, these findings showed that pregnancy was a stressful physiological event that increased the leukocyte count with a slight alteration in the erythrogram of Dorper ewes.

O sistema hematopoiético sofre mudanças durante a gestação para atender o desenvolvimento fetal e as necessidades maternas. Este estudo comparou os parâmetros hematológicos entre ovelhas com gestação simples e gemelar durante a prenhez, parto e pós-parto. O estudo foi realizado em 60 ovelhas Dorper prenhes, saudáveis, divididas em dois grupos experimentais: Grupo 1 (G1) com gestação simples (n = 30); e Grupo 2 (G2) com gestação gemelar (n = 30). Amostras de sangue foram colhidos de todas as ovelhas em diferentes momentos: imediatamente antes da inseminação artificial em tempo fixo (IA); nos dias 30, 90, 120, 130 e 140 de gestação; imediatamente após o parto; e às 24h e 48h pós-parto. A análise estatística comparou os dois grupos nos diferentes momentos (P < 0,05). Anemia leve, normocítica e hipocrômica foi detectada desde a IA e ao longo da gestação, nas ovelhas de ambos os grupos, mas não houve relevância clínica. Na fase periparto (do 140º dia de gestação às 48h pós-parto), as ovelhas com gestação gemelar (G2) mostraram valores do eritrograma e proporção neutrófilos: linfócitos mais elevados do que as ovelhas com gestação simples (G1). Isso indicou maior adaptação hematopoiética da ovelha para o desenvolvimento de dois fetos. Com exceção do número de eosinófilos, todos os parâmetros do leucograma foram influenciados pela gestação de forma semelhante em ambos os grupos, e foi caracterizada principalmente por leucocitose com neutrofilia no periparto devido ao alto nível de cortisol endógeno no parto. Assim, os achados mostraram que a gestação foi um evento fisiológico estressante que aumentou a contagem de leucócitos com leve alteração no eritrograma de ovelhas Dorper.

Comparison of hematological parameters between single and twin pregnancies in Dorper ewes during gestation, lambing, and postpartum / Comparação dos parâmetros hematológicos entre ovelhas Dorper de gestação simples e gemelar durante a prenhez, parto e pós-parto

The hematopoietic system changes during the pregnancy to carry fetal development and maternal needs. This study compared the hematological parameters between ewes with single and twin pregnancies during gestation, delivery, and postpartum. The experiment was conducted on 60 healthy pregnant Dorper ewes that were divided into two experimental groups: Group 1 (G1), with single pregnancies (n=30), and Group 2 (G2), with twin pregnancies (n=30). Blood samples were collected from all ewes at different times: immediately before fixed-time artificial insemination (AI); on day 30, 90, 120, 130, and 140 of pregnancy; immediately after delivery; and at 24h and 48h postpartum. Statistical analysis compared the two groups at different times (P<0.05). Mild, normocytic, and hypochromic anemia was detected in all ewes from AI time and throughout pregnancy from both groups, but did not prove to be of clinical relevance. In the peripartum stage (from the 140th day of pregnancy to 48h postpartum), the ewes with twin pregnancies (G2) exhibited higher erythrogram values and neutrophil: lymphocyte ratio than did ewes with single pregnancies (G1). This indicated a greater hematopoietic adaptation in the body during the development of two fetuses. Except for the eosinophil numbers, all leukogram parameters were influenced by pregnancy in a similar way in both groups, and was characterized mainly by leukocytosis with neutrophilia during peripartum due to the high presence of endogenous cortisol at delivery. Thus, these findings showed that pregnancy was a stressful physiological event that increased the leukocyte count with a slight alteration in the erythrogram of Dorper ewes.(AU)

O sistema hematopoiético sofre mudanças durante a gestação para atender o desenvolvimento fetal e as necessidades maternas. Este estudo comparou os parâmetros hematológicos entre ovelhas com gestação simples e gemelar durante a prenhez, parto e pós-parto. O estudo foi realizado em 60 ovelhas Dorper prenhes, saudáveis, divididas em dois grupos experimentais: Grupo 1 (G1) com gestação simples (n = 30); e Grupo 2 (G2) com gestação gemelar (n = 30). Amostras de sangue foram colhidos de todas as ovelhas em diferentes momentos: imediatamente antes da inseminação artificial em tempo fixo (IA); nos dias 30, 90, 120, 130 e 140 de gestação; imediatamente após o parto; e às 24h e 48h pós-parto. A análise estatística comparou os dois grupos nos diferentes momentos (P < 0,05). Anemia leve, normocítica e hipocrômica foi detectada desde a IA e ao longo da gestação, nas ovelhas de ambos os grupos, mas não houve relevância clínica. Na fase periparto (do 140º dia de gestação às 48h pós-parto), as ovelhas com gestação gemelar (G2) mostraram valores do eritrograma e proporção neutrófilos: linfócitos mais elevados do que as ovelhas com gestação simples (G1). Isso indicou maior adaptação hematopoiética da ovelha para o desenvolvimento de dois fetos. Com exceção do número de eosinófilos, todos os parâmetros do leucograma foram influenciados pela gestação de forma semelhante em ambos os grupos, e foi caracterizada principalmente por leucocitose com neutrofilia no periparto devido ao alto nível de cortisol endógeno no parto. Assim, os achados mostraram que a gestação foi um evento fisiológico estressante que aumentou a contagem de leucócitos com leve alteração no eritrograma de ovelhas Dorper.(AU)

IATF em números: evolução e projeção futura / FTAI in numbers: evolution and future projection

Estudos realizados pelo Departamento de Reprodução Animal da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (FMVZ/USP) apontam que a IATF (inseminação artificial em tempo fixo) atingiu mais um recorde em 2021 e superou 26 milhões de procedimentos de sincronização. O mercado de IATF cresceu 25% entre 2020 e 2021 e representou 93% das inseminações efetuadas no Brasil. A tecnologia de IATF proporciona uma abordagem organizada e prática para o uso da inseminação artificial (IA), além de melhorar a eficiência reprodutiva, genética e produtiva dos rebanhos. Segundo dados da ASBIA (Associação Brasileira de Inseminação Artificial), em 2002 o mercado nacional de IA comercializou 7,1 milhões de doses de sêmen, para um rebanho estimado de 74,9 milhões de matrizes (vacas e novilhas; ANUALPEC). Em 2021, com rebanho semelhante de matrizes, o mercado atingiu 28,4 milhões de doses de sêmen comercializadas, com crescimento de 400% nesse período. Em 2002, apenas 5,8% das matrizes de leite e de corte do rebanho brasileiro eram inseminadas artificialmente. Em 2021, foram inseminadas 23,4% das fêmeas do total das matrizes do rebanho nacional. No início das avaliações (2002), 4.4 milhões de matrizes bovinas eram inseminadas artificialmente no Brasil, atingindo 17.5 milhões de matrizes em 2021. Entre 2002 e 2021, a taxa de crescimento anual composta (CAGR: Compound Annual Growth Rate) do número de protocolos de sincronização comercializados para IATF foi de 34,1%. Essas informações demonstram a significativa evolução da utilização da IA e a consolidação da tecnologia pelo setor produtivo.(AU)

Studies carried out by the Department of Animal Reproduction of the Faculty of Veterinary Medicine and Animal Science of the University of São Paulo (FMVZ/USP) indicate that FTAI (fixed-time artificial insemination) reached another record in 2021 and exceeded 26 million synchronization protocols. The FTAI market grew increased 25% between 2020 and 2021 and represented 93% of all inseminations performed in Brazil. FTAI technology provides an organized and practical approach to the use of artificial insemination (AI), in addition to improving the reproductive, genetic and productive efficiency of herds. According to data from ASBIA (Brazilian Association of Artificial Insemination), in 2002 the national AI market sold 7.1 million doses of semen to an estimated herd of 74.9 million females (cows and heifers; ANUALPEC). In 2021, with a similar number of females, the market reached 28.4 million doses of semen sold, with growth of 400% in this period. In 2002, only 5.8% of dairy and beef females in the Brazilian herd were artificially inseminated. In 2021, 23.4% of the females of the total number of females in the national herd were inseminated (4 times growth). At the beginning of the evaluations (2002), 4.4 million females were artificially inseminated in Brazil, reaching 17.5 million cows and heifers in 2021. Between 2002 and 2021, the Compound Annual Growth Rate (CAGR) of the number of synchronization protocols marketed was 34.1%. This information demonstrates the significant evolution of the use of AI and the consolidation of FTAI technology by the productive sector.(AU)

Strategic re-use of intravaginal progesterone devices increases conception rate in primiparous Nellore cows / Reutilização estratégica de dispositivo intravaginal de progesterona aumenta a taxa de concepção em vacas Nelore primíparas

In the present study, we investigate the effect of the presence or absence of corpus luteum (CL) at the beginning of a fixed-time artificial insemination (FTAI) protocol and to evaluate the impact of one-time use of intravaginal progesterone device (P4 device) in cows with or without CL. A total of 776 primiparous Nellore cows were subjected to FTAI approximately 45 days postpartum. In Experiment 1, 476 cows were divided into two experimental groups: with (CL-present, n=113) or without (CL-absent, n=363) CL, after ultrasound evaluation. On day 0 (D0), all cows received a new P4 device (1.0 g) and 2.0 mg estradiol benzoate (EB). Eight days later (D8), the P4 devices were withdrawn, and prostaglandin (15 mg), estradiol cypionate (0.5 mg), and eCG (300 IU) were administered i.m. All cows were inseminated 48 h after P4 device withdrawal (D10). In Experiment 2, the cows (n= 300) received (at D0) P4 devices that were previously used once in other cows with (n=109) or without CL (n=191) and 2 mg of EB. The same protocol as that used in Experiment 1 was performed from D8 onwards. In Experiment 1, the overall conception rate after FTAI was 55% (262/476). No difference was found in the conception rate between CL-present and CL-absent cows (52.2 vs. 55.5%). In Experiment 2, the conception rate obtained with P4 devices previously used in cows with CL (58.7%) was greater (P<0.05) than that obtained with P4 devices previously used in cows without CL (42.9%). Thus, this strategy resulted in a 15.8% increase in conception rate. In conclusion, the presence or absence of CL at the beginning of the FTAI protocol did not affect the conception rate in cows synchronized with the new P4 device, but the insertion of P4 devices previously used in cows with CL enhanced the conception rates in cows without CL.

No presente estudo, investigamos o efeito da presença ou ausência de corpo lúteo (CL) no início de um protocolo de inseminação artificial em tempo fixo (IATF) e avaliamos o impacto do uso único de dispositivo intravaginal de progesterona (dispositivo P4) em vacas com ou sem CL. Um total de 776 vacas Nelore primíparas, aproximadamente 45 dias pós-parto foram submetidas à IATF. No Experimento 1, após avaliação ultrassonográfica, 476 vacas foram divididas em dois grupos experimentais: com (CL-presente, n=113) ou sem (CL-ausente, n=363) CL. No dia 0 (D0), todas as vacas receberam um novo dispositivo de P4 (1,0 g) e 2.0 mg de benzoato de estradiol (BE). Após 8 dias (D8), os dispositivos P4 foram retirados e prostaglandina (15 mg), cipionato de estradiol (0,5 mg) e eCG (300 UI) foram administrados i.m. Todas as vacas foram inseminadas 48 horas após a retirada do dispositivo de P4 (D10). No Experimento 2, as vacas (n= 300) receberam (no D0) um dispositivo de P4 previamente utilizado uma única vez em outras vacas com (n=109) ou sem CL (n=191) e 2 mg de BE. O mesmo protocolo utilizado no Experimento 1 foi realizado a partir do D8. No experimento 1, a taxa geral de concepção após IATF foi de 55% (262/476). Não foi encontrada diferença na taxa de concepção entre as vacas com CL presente e CL ausente (52,2 vs. 55,5%). No Experimento 2, a taxa de concepção obtida com dispositivos P4 previamente utilizados em vacas com CL-presente (58,7%) foi maior (P<0,05) quando comparada aos dispositivos P4 previamente utilizados em vacas com CL-ausente (42,9%). Essa estratégia resultou em aumento de 15,8% na taxa de concepção. Em conclusão, a presença ou ausência de CL no início do protocolo de IATF não afetou a taxa de concepção em vacas sincronizadas com dispositivo novo de P4; e a eficácia dos dispositivos de P4 previamente utilizados em vacas com CL é maior durante seu segundo uso em vacas sem CL.

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.

Análises computadorizadas da motilidade espermática (CASA): conceitos e possibilidades de padrões / Computerized analysis of sperm motility (CASA): concepts and possibilities of standards

O melhoramento genético possibilitou a evolução da eficiência e taxas de desfrute da pecuária nacional. A biotécnica da IATF (Inseminação Artificial por Tempo Fixo) consolidou-se como a principal ferramenta de disseminação de genética melhorada em rebanhos de leite e de corte. A avaliação espermática laboratorial tem o objetivo de analisar o potencial de reprodutores/partidas de sêmen e buscar a desafiadora tarefa de determinar e estabelecer características confiáveis que possam ser utilizadas como indicadores de fertilidade. Nesse contexto emerge o sistema CASA (Computer-Assisted Sperm Analysis) como ferramenta promissora para obtenção de parâmetros indicativos de fertilidade seminal.(AU)

Genetic improvement enabled the evolution and efficiencies of national livestock activity. The IATF (Fixed Time Artificial Insemination) biotechnology, has established itself as the main tool for the dissemination of improved genetics in dairy and beef herds. Laboratory sperm evaluation aims to analyze the potential of a sires/semen batches and seek the challenging task of determining and establishing reliable characteristics that can be used as fertility indicators. In this context, the computerized system of sperm motility (CASA) emerges as a promising tool for obtaining parameters indicative of seminal fertility.(AU)

Níveis de progesterona e os parâmetros reprodutivos no período periovulatório de vacas Nelore submetidas ao protocolo de IATF / Progesterone levels and reproductive parameters in the periovulatory period of Nellore cows under FTAI protocol

Background: Fixed Time Artificial Insemination (FTAI) has achieved a significant evolution in the last 18 years, however, despite the progress achieved by modern FTAI programs, the conception rates obtained are still low. Therefore, this study aimed to evaluate the interrelation between progesterone levels in the periovulatory period and reproductive parameters of Nellore cows submitted to an FTAI protocol. Materials, Methods & Results: On a random day, called day 0 (D0), 57 cows received a P4 device associated with the intramuscular (IM) application of 2.0 mg of estradiol benzoate. On D9, the P4 devices were removed and then were administered 500 µg of cloprostenol sodium IM; 0.6 mg of estradiol cypionate IM and 300 IUI of Equine Chorionic Gonadotrophin IM. Blood samples were collected for the determination of serum P4 concentrations on D9 and D11 of the protocol. The evaluations of follicular diameter (DFOL), follicular wall area (AFOL) and the vascularization area of the follicle wall (VFOL) were carried out on D11 using B-mode ultrasonography examination and colour Doppler, and then the artificial inseminations were performed. The evaluation of the corpus luteum diameter (CLD), of the total corpus luteum area (CLA), of the area of corpus luteum vascularization (CLV) and blood sampling for determination of postovulatory P4 levels (Post-P4) were performed on D24. For the analysis of the P4 concentration the chemiluminescence method was used, with a sensitivity of 0.1 ng/mL. According to the P4 concentrations on D11, cows were divided into 2 groups, LOW LEVELS OF P4 and HIGH LEVELS OF P4. The diagnosis of pregnancy was performed using transrectal ultrasonography on D45, at this point the cows were divided into 2 groups, PREGNANT and NON-PREGNANT. The correlation between DFOL and P4 dosage on D11 was moderate, negative and significant and between the AFOL and the serum P4 levels on D9, was moderate, negative and significant. As for the other correlations between follicular and luteal parameters and serum P4 levels, these were low to moderate, negative and not significant. Cows in the LOW LEVELS OF P4 group had significantly larger diameter and follicular areas than the cows in the HIGH LEVELS OF P4 group, the other follicular and luteal parameters showed no statistical difference. Of the total 57 cows that were inseminated, 30 cows became pregnant. Cows in the PREGNANT group had serum P4 levels on D9 equivalent to that obtained by the NON-PREGNANT group. However, at D11 the cows that became pregnant presented significantly lower serum P4 levels than cows that did not become pregnant. Discussion: The results of the interrelation between follicular parameters and P4 levels obtained in the present study, pointed out that the lower the levels of P4, the higher the follicular parameters, corroborating with other authors. Thus, larger preovulatory follicles provided high ovulation rates. Periovulatory serum P4 levels did not significantly affect the morphofunctional parameters of the CL. Such findings may be justified by high periovulatory P4 levels resulting from less efficient luteolysis, exert a negative effect on the results of FTAI protocols, because progesterone inhibits the release of LH pulses. It is concluded that lower periovulatory P4 levels established a favourable condition for follicular development and fertility, however, morphofunctional parameters of the corpus luteum were not affected.

Fixed-time artificial insemination protocols on brazilian locally adapted breed gilts on ovulatory response and embryo production

Abstract The aim of this study was to use estrus synchronization protocols to favor fixed-time artificial insemination and consequently fixed-time embryo collection, and increase embryo production using eCG, in gits. In a cross over design, nine Piau breed gilts were subjected to 18 days of oral progesterone; P4 group did not receive any further; GnRH group received 25µg of GnRH 104 hours after the final application of P4; and eCG+GnRH group received 1000IU of eCG 24 hours after the final P4 in addition to GnRH for subsequent embryo collection, that was performed six days after first AI, by laparotomy. Artificial insemination was performed after 12 and 24 hours of estrus in P4 group, and 128 and 144 hours in GnRH and eCG+GnRH groups. The number of CL (8.6±3.9; 8.3±2.1; 26.7±15.0) and anovulatory follicles (4.3±3.7; 3.9±3.9; 17.2±9.5) was higher in the eCG+GnRH gilts (P<0.05). However, the use of 1000 IU of eCG reduced (P<0.05) the number of total structures (5.2±3.6; 5.1±3.1; 1.7±2.7), viable embryos (5.0±3.5; 4.8±3.3; 0.4±0.7), freezable embryos (3.6±3.4; 3.3±3.8; 0.1±0.3) and recovery rate (63.7±38.9; 58.6±24.7; 5.38±9.5). P4 and GnRH protocols were effective in the production and recovery of embryos. However, the use of 1000 IU of eCG, 24 hours after P4, was not effective in promoting the production of embryos, although the animals had superovulated.

Fixed-time artificial insemination protocols on brazilian locally adapted breed gilts on ovulatory response and embryo production

The aim of this study was to use estrus synchronization protocols to favor fixed-time artificial insemination and consequently fixed-time embryo collection, and increase embryo production using eCG, in gits. In a cross over design, nine Piau breed gilts were subjected to 18 days of oral progesterone; P4 group did not receive any further; GnRH group received 25µg of GnRH 104 hours after the final application of P4; and eCG+GnRH group received 1000IU of eCG 24 hours after the final P4 in addition to GnRH for subsequent embryo collection, that was performed six days after first AI, by laparotomy. Artificial insemination was performed after 12 and 24 hours of estrus in P4 group, and 128 and 144 hours in GnRH and eCG+GnRH groups. The number of CL (8.6±3.9; 8.3±2.1; 26.7±15.0) and anovulatory follicles (4.3±3.7; 3.9±3.9; 17.2±9.5) was higher in the eCG+GnRH gilts (P<0.05). However, the use of 1000 IU of eCG reduced (P<0.05) the number of total structures (5.2±3.6; 5.1±3.1; 1.7±2.7), viable embryos (5.0±3.5; 4.8±3.3; 0.4±0.7), freezable embryos (3.6±3.4; 3.3±3.8; 0.1±0.3) and recovery rate (63.7±38.9; 58.6±24.7; 5.38±9.5). P4 and GnRH protocols were effective in the production and recovery of embryos. However, the use of 1000 IU of eCG, 24 hours after P4, was not effective in promoting the production of embryos, although the animals had superovulated.(AU)