Applying assisted reproductive technology and reproductive management to reduce CO2-equivalent emission in dairy and beef cattle: a review

Methane emission from beef and dairy cattle combined contributes around 4.5-5.0% of total anthropogenic global methane. In addition to enteric methane (CH4) produced by the rumen, cattle production also contributes carbon dioxide (CO2) (feed), nitrous oxide (N2O) (feed production, manure) and other CH4 (manure) to the total greenhouse gas (GHG) budget of beef and dairy production systems. The relative contribution in standard dairy systems is typically enteric CH4 58%, feed 29% and manure 10%. Herds with low production efficiency can have an enteric CH4 contribution up to 90%. Digestibility of feed can impact CH4 emission intensity. Low fertility herds also have a greater enteric CH4 contribution. Animals with good feed conversion efficiency have a lower emission intensity of CH4/kg of meat or milk. Feed efficient heifers tend to be lean and have delayed puberty. Fertility is a major driver of profit in both beef and dairy cattle, and it is highly important to apply multi-trait selection when shifting herds towards improved efficiency and reduced CH4. Single nucleotide polymorphisms (SNPs) have been identified for feed efficiency in cattle and are used in genomic selection. SNPs can be utilized in artificial insemination and embryo transfer to increase the proportion of cattle that have the attributes of efficiency, fertility and reduced enteric CH4. Prepubertal heifers genomically selected for favourable traits can have oocytes recovered to produce IVF embryos. Reproductive technology is predicted to be increasingly adopted to reduce generation interval and accelerate the rate of genetic gain for efficiency, fertility and low CH4 in cattle. The relatively high contribution of cattle to anthropogenic global methane has focussed attention on strategies to reduce enteric CH4 without compromising efficiency and fertility. Assisted reproductive technology has an important role in achieving the goal of multiplying and distributing cattle that have good efficiency, fertility and low CH4.(AU)

Use of new recombinant proteins for ovarian stimulation in ruminants

Currently, gonadotropin products (follicle stimulating hormone, FSH, and luteinizing hormone, LH) used in animal reproduction are produced by extraction and purification from abattoir-derived pituitary glands. This method, relying on animal-derived materials, carries the potential risk of hormone contamination and pathogen transmission. Additionally, chorionic gonadotropins are extracted from the blood of pregnant mares (equine chorionic gonadotropin; eCG) or the urine of pregnant women (human chorionic gonadotropin; hCG). However, recent advancements have introduced recombinant gonadotropins for assisted animal reproduction therapies. The traditional use of FSH for superovulation has limitations, including labor requirements and variability in superovulation response, affecting the success of in vivo (SOV) and in vitro (OPU/IVEP) embryo production. FSH treatment for superstimulation before OPU can promote the growth of a homogenous follicular population and the recovery of competent oocytes suitable for IVEP procedures. At present, a single injection of a preparation of long-acting bovine recombinant FSH (rFSH) produced similar superovulation responses resulting in the production of good-quality in vivo and in vitro embryos. Furthermore, the treatment with eCG at FTAI protocol has demonstrated its efficacy in promoting follicular growth, ovulation, and P/AI, mainly in heifers and anestrous cows. Currently, treatment with recombinant glycoproteins with eCG-like activity (r-eCG) have shown promising results in increasing follicular growth, ovulation, and P/AI in cows submitted to P4/E2 -based protocols. Bovine somatotropin (bST) is a naturally occurring hormone found in cows. Recombinant bovine somatotropin (rbST), produced through genetic engineering techniques, has shown potential in enhancing reproductive outcomes in ruminants. Treatment with rbST has been found to improve P/IA, increase donor embryo production, and enhance P/ET in recipients. The use of recombinant hormones allows to produce non-animal-derived products, offering several advantages in assisted reproductive technologies for ruminants. This advancement opens up new possibilities for improving reproductive efficiency and success rates in the field of animal reproduction.(AU)

Productive and reproductive performance of crossbred dairy heifers with induced lactation and efficacy of antimicrobial therapy associated with internal teat sealants / Desempenho produtivo e reprodutivo de novilhas com lactação induzida e eficácia da terapia antimicrobiana associada com selante interno de tetos

This study evaluated (a) the efficacy of an association between injectable antibiotic therapy and sealant (ATBS) on milk yield (MY), somatic cell count (SCC), and prevalence of intramammary infections (IMI); and (b) the efficacy of gonadotropin-releasing hormone (GnRH) on follicular cyst (FCs) resolution (cyclicity at the 45th day in milk; DIM) and cumulative pregnancy rate (CPR) in heifers submitted to a lactation induction protocol (LIP). A total of 114 crossbred (Holstein × Jersey) heifers, with 34.7 ± 4.8 months and 439 ± 56.35 kg were submitted to LIP. On the 5th day of the LIP, the heifers were assigned to (i) ATBS (n = 57) with 7 mg/kg of norfloxacin associated with sealant and (ii) Control 1 (n = 57; CONT1) with no treatments. Lactation began on the 21st day of LIP and the 15th DIM, FCs were diagnosed and 106 heifers were randomized into two treatment groups with 53 heifers each: (i) GnRH (5 mL injectable GnRH) and (ii) Control 2 (CONT2; no treatment). Of the 114 heifers initially induced, 83.33% (n = 95) responded to LIP with an average MY of 15.19 kg/milk/day during 22 weeks of lactation. In the first 14 DIM, the IMI prevalence was 18% and 28% for heifers ATBS and CONT1 treated, respectively. Additionally, coagulase-negative Staphylococcus was the most frequently isolated group of pathogens. Mammary quarters that received ATBS treatment had a lower risk of IMI and SCC than CONT1. The cyclicity at 45 DIM was 68% (ATBS) and 35% (CONT1), and 57% and 46% for animals in the GnRH and CONT2. CPR was 60% in the ATBS group and 89% in CONT1, but GnRH treatment did not affect the CPR. In conclusion, LIP was effective in stimulating MY in heifers, and the IMI prevalence decreased with ATBS treatment. Also, the use of GnRH did not affect the FC regression, cyclicity at 45 DIM, and CPR.(AU)

Este estudo avaliou a (i) eficácia da associação entre antibioticoterapia injetável e selante interno de tetos (ATBS) na produção de leite (PL), contagem de células somáticas (CCS), e prevalência de infecções intramamárias (IIM); e (ii) eficácia do hormônio liberador de gonadotrofina (GnRH) na resolução de cistos foliculares (CFs), ciclicidade ao 45º dia em lactação (DEL) e taxa de prenhez cumulativa (TPC) em novilhas submetidas a um protocolo de indução de lactação (PIL). Um total de 114 novilhas mestiças (Holandês × Jersey), com 34,7 ± 4,8 meses e 439 ± 56,35 kg foram submetidas ao PIL. No 5º dia do PIL, as novilhas receberam: (i) ATBS (n = 57) com 7 mg/kg de norfloxacina associada ao selante interno de tetos e (ii) Controle 1 (n = 57; CONT1) sem tratamento. A lactação teve início no 21º dia do PIL e no 15º DEL, foram diagnosticados CFs e 106 novilhas foram agrupadas em dois grupos de tratamento com 53 novilhas em cada: (i) GnRH (5 mL de GnRH injetável) e (ii) Controle 2 (CONT2; sem tratamento). Das 114 novilhas inicialmente induzidas, 83,33% (n = 95) responderam ao PIL com PL média de 15,19 kg/leite/d durante 22 semanas de lactação. Nos primeiros 14 DEL a prevalência de IIM foi de 18% e 28% para as novilhas tratadas com ATBS e CONT1, respectivamente. Além disso, estafilococos coagulase negativa foram o grupo de patógenos mais frequentemente isolados. Quartos mamários tratados com ATBS tiveram menor risco (0,56) de IIM e menor CCS do que CONT1. A ciclicidade a 45 DEL foi de 68% (ATBS) e 35% (CONT1), e 57% e 46% para os animais no GnRH e CONT2. A TPC foi de 60% no grupo ATBS e 89% no CONT1, porém o tratamento com GnRH não afetou a TPC. Em conclusão, o PIL foi eficaz em estimular a PL em novilhas tardias e a prevalência de IIM diminiuiu com o tratamento ATBS. Além disso, o uso de GnRH não afetou a regressão de CF, ciclicidade em 45 DEL e a TPC.(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)

Mitos e realidades sobre a inseminação artificial em tempo fixo (IATF) em bovinos de corte / Myths and realities of timed artificial insemination in beef cattle

O sistema de cria é um dos principais setores da bovinocultura de corte, com impactos diretos na ocupação da terra (70% das pastagens são ocupadas pela cria) e na produtividade da cadeia da carne. O número e o peso dos bezerros produzidos por matriz e a idade das novilhas ao primeiro parto influenciam diretamente a eficiência do setor. As biotecnologias da reprodução, com destaque para a inseminação artificial em tempo fixo (IATF), têm colaborado significativamente para o desenvolvimento de um sistema de produção cada vez mais eficiente e sustentável. Em 2020 foram comercializadas no Brasil 23,7 milhões de doses de sêmen e 21,3 milhões de protocolos de IATF (90% das inseminações foram realizadas por IATF). Em 2002 eram utilizados apenas 100 mil procedimentos de IATF, que representavam somente 1% das inseminações realizadas. Nesse mesmo período (2002 a 2020), o percentual de matrizes inseminadas passou de 5% para 20% (acréscimo de 400%), com aumento de 213 vezes no empego da IATF. Os programas de IATF oferecem uma abordagem organizada e prática para o uso da IA, além de melhorarem a eficiência reprodutiva, genética e produtiva dos rebanhos. O uso da IATF antecipa a prenhez na estação de monta e a idade a primeira concepção das novilhas, aumentando significativamente a eficiência reprodutiva, produtiva e o retorno econômico do setor. Recentes estudos evidenciaram que os sistemas de cria que utilizam a IATF apresentam redução de 37,7% na emissão de CO2 equivalentes (produz mais bezerros de qualidade genética com menos matrizes que a monta natural), colaborando com a sustentabilidade da pecuária. Evidencia-se, também, que a nutrição, além de outros fatores, exerce papel importante na reprodução e afeta diretamente o desempenho da IATF. Entretanto, ainda existem mitos e realidades sobre os fatores que podem afetar o sucesso desta biotecnologia. O objetivo dessa revisão é apresentar e discutir os principais temas que impactam a eficiência da IATF em rebanhos de corte.

The cow-calf operation system is one is one of the main sectors of beef production, with direct impacts on land occupation (70% of pastures are occupied by the cow-calf operation system) and on the productivity of the meat chain. The number and the weight of calves produced per cow and the age of the heifer at first calving directly impact the efficiency of the sector. Reproductive biotechnologies, with emphasis on fixed-time artificial insemination (FTAI), have significantly contributed to the development of an efficient and sustainable production system. In 2020, 23.7 million doses of semen and 21.3 million FTAI protocols were marketed in Brazil (90% of inseminations were performed by FTAI). In 2002, only 100,000 FTAI procedures were used (a 213-fold increase in 19 years), which represented only 1% of the inseminations performed. During this same period (2002 to 2020), Brazil went from 5% to 20% of inseminated cow and heifers (increase of 400%). FTAI programs provide an organized and practical approach to the use of AI, as well as improve the reproductive, genetic and productive efficiency of the herds. The use of the FTAI anticipates the conception of cows in the breeding season and the age of the first conception of heifers, significantly increasing the reproductive and productive efficiency and the economic return of livestock. Recent studies have shown that breeding systems that use FTAI present a reduction of 37.7% in the emission of CO2 equivalents (it produces more calves of genetic quality with fewer dams than natural service), collaborating and with the sustainability of livestock. It is also evident that nutrition plays an important role in reproduction and directly affects the FTAI performance. However, there are still myths and realities about the factors that can affect the success of this biotechnology. The aim of this review is to present and discuss the main topics that impact the efficiency of FTAI in beef herds.

Different times to perform timed artificial insemination when using a P4/E2/eCG-based protocol in buffalo / Momentos diferentes para executar a inseminação artificial em tempo fixo utilizando o protocolo à base de P4/E2/eCG em búfalas

The aim of this study was to evaluate different times for timed artificial insemination (TAI) in buffalo submitted to a P4/E2/eCG-based protocol. In this study, 204 buffaloes were distributed into one of two groups (TAI56, n=103 and TAI64, n=101). At a random stage of the oestrous cycle (Day 0 = D0), in the morning (TAI56, a.m.) or afternoon (TAI64, p.m.), buffaloes received an intravaginal progesterone device (P4; 1.0 g) plus EB (2.0 mg i.m.). On D9 a.m. (TAI56) or p.m. (TAI64), the P4 was removed and buffaloes received PGF2a (0.53 mg i.m. sodium cloprostenol) and eCG (400 IU i.m.). On D10 a.m. (TAI56) or p.m. (TAI64), 24 h after P4 removal, buffaloes were treated with EB (1.0 mg i.m.). Buffaloes from TAI56 and TAI64 were inseminated 56 and 64 h after P4 removal (D11, p.m. and D12, a.m., respectively). Ultrasound examinations were performed on D0 to ascertain ovarian follicular status, at TAI to measure the diameter of the dominant follicle (DF) and D42 for pregnancy diagnosis. The statistical analysis was performed using the GLIMMIX procedure of SAS®. There was no difference between TAI56 and TAI64 for the diameter of the DF at TAI and the pregnancy per TAI. It was concluded that TAI 56 or 64 h after P4 removal did not affect fertility in buffaloes submitted to the induction of ovulation with EB. The present research supports that is possible to perform TAI at any time throughout the day in buffalo synchronized during the non-breeding season.(AU)

O objetivo deste estudo foi avaliar diferentes momentos para a realização da IATF em búfalas submetidas a um protocolo à base de P4/E2/eCG. Neste estudo, 204 búfalas foram distribuídas em um de dois grupos (IATF56, n=103 e IATF64, n=101). Em estágio aleatório do ciclo estral (Dia 0 = D0), pela manhã (IATF56, manhã) ou pela tarde (IATF64, tarde), as búfalas receberam um dispositivo intravaginal de progesterona (P4; 1,0 g) e BE (2,0 mg i.m.). No D9 pela manhã (IATF56) ou pela tarde (IATF64), a P4 foi removida e as búfalas receberam PGF2a (0,53 mg i.m. cloprostenol sódico) e eCG (400 UI i.m.). No D10 pela manhã (IATF56) ou pela tarde (IATF64), 24 h após a remoção da P4, as búfalas foram tratadas com BE (1,0 mg i.m.). As búfalas dos grupos IATF56 e IATF64 foram inseminadas 56 e 64 h após a remoção da P4 (D11, pela tarde e D12, pela manhã, respectivamente). Avaliações ultrassonográficas foram realizadas no D0 para verificar o status folicular ovariano, na IATF para medir o diâmetro do folículo dominante (FD) e no D42 para o diagnóstico de gestação. A análise estatística foi realizada utilizando o procedimento GLIMMIX do SAS®. Não houve diferença entre os grupos IATF56 e IATF64 no diâmetro do FD na IATF e na prenhez por IATF. Conclui-se que a IATF 56 ou 64 h após a remoção da P4 não afeta a fertilidade de búfalas submetidas à indução da ovulação com BE. A presente pesquisa evidencia que é possível realizar a IATF durante todo o dia em búfalas sincronizadas durante a estação reprodutiva desfavorável.(AU)

Estratégias para aumentar a produção de embriões em bovinos / Strategies to increase embryo production in cattle

As biotecnologias para produção de embriões in vivo e in vitro são de grande importância para acelerar o ganho genético dos rebanhos de corte e de leite. No entanto, o sucesso desses processos depende diretamente da quantidade e da qualidade dos oócitos da doadora de embrião. Diversos fatores influenciam a produção de embriões como a população folicular, a idade da doadora, o estresse térmico, o status metabólico e o status reprodutivo. Na atualidade, vários estudos têm sido desenvolvidos para elaborar estratégias que contornem estes desafios e aumentem a eficiência das técnicas de produção de embriões. Dentre os tratamentos estabelecidos para melhorar a produção de embriões das doadoras destacam-se a utilização de FSH, rBST, propilenoglicol e células tronco mesenquimais.(AU)

Biotechnologies for producing in vivo and in vitro embryos are very important to accelerate the genetic gain of beef and dairy herds. However, the success of these processes depend directly on the quantity and quality of the donors oocytes. Many factors influence the embryo production, such as follicle population, age, heat stress, metabolic status and reproductive status. Recently, many studies have been conducted to elaborate strategies that can overcome these issues and increase the efficiency of the embryo production techniques. Among the treatments developed to improve the embryo production, the use of FSH, rBST, propylene glycol and mesenchymal stem cells stand out.(AU)

Estratégias para aumentar a produção de embriões em bovinos / Strategies to increase embryo production in cattle

As biotecnologias para produção de embriões in vivo e in vitro são de grande importância para acelerar o ganho genético dos rebanhos de corte e de leite. No entanto, o sucesso desses processos depende diretamente da quantidade e da qualidade dos oócitos da doadora de embrião. Diversos fatores influenciam a produção de embriões como a população folicular, a idade da doadora, o estresse térmico, o status metabólico e o status reprodutivo. Na atualidade, vários estudos têm sido desenvolvidos para elaborar estratégias que contornem estes desafios e aumentem a eficiência das técnicas de produção de embriões. Dentre os tratamentos estabelecidos para melhorar a produção de embriões das doadoras destacam-se a utilização de FSH, rBST, propilenoglicol e células tronco mesenquimais.

Biotechnologies for producing in vivo and in vitro embryos are very important to accelerate the genetic gain of beef and dairy herds. However, the success of these processes depend directly on the quantity and quality of the donors oocytes. Many factors influence the embryo production, such as follicle population, age, heat stress, metabolic status and reproductive status. Recently, many studies have been conducted to elaborate strategies that can overcome these issues and increase the efficiency of the embryo production techniques. Among the treatments developed to improve the embryo production, the use of FSH, rBST, propylene glycol and mesenchymal stem cells stand out.

Evolução e perspectivas da inseminação artificial em bovinos / Evolution and perspectives of timed artificial insemination in cattle

A inseminação artificial (IA) em bovinos tem sido aplicada em todo o mundo com o intuito de melhorar o ganho genético e a eficiência reprodutiva dos rebanhos. Com o objetivo de facilitar a utilização da IA foram desenvolvidos protocolos de inseminação artificial em tempo fixo (IATF) que promovem o controle do crescimento folicular e da ovulação e permitem a aplicação da IA em dias predeterminados, sem a necessidade de detecção de estro e com elevadas taxas de prenhez. Nos últimos 20 anos, vários protocolos de sincronização para IATF foram estudados para atender diferentes realidades de manejo, raças e categorias de animais. Atualmente, 86% das inseminações no Brasil estão sendo realizadas por IATF (13,6 milhões de IATF de um total de 15,4 milhões de doses de sêmen comercializadas em 2018). Com a colaboração dessa tecnologia, verificou-se que o percentual de fêmeas em idade reprodutiva inseminadas artificialmente passou de 5,8% em 2002 para 13,1% em 2018. O aumento de uso da IATF representa considerável incremento de produtividade quando comparado com a monta natural, maximizando o retorno econômico para as fazendas de corte e de leite.(AU)

Artificial insemination in cattle has been used worldwide to improve the genetic gain and reproductive efficiency of the herds. In order to facilitate the use of AI, several protocols for timed artificial insemination (TAI) have been developed, which promote the control of follicular growth and ovulation, allowing the use of AI in predetermined days, without the necessity of estrus detection and with satisfactory pregnancy rates. In the last 20 years, a wide variety of protocols have been studied to address different management realities, breeds and animal categories. Currently, 86% of artificial inseminations in Brazil are performed using TAI (13.6 million TAI of 15.4 million batches of semen commercialized in 2018). The percentage of females in reproductive age inseminated in Brazil went from 5.8% in 2002 to 13.1% in 2018. Reproductive programs that use TAI present increase in productivity when compared to natural breeding, maximizing the economic gain for beef and dairy properties.(AU)

Can mineral supplementation modify the characteristics of young buffalo ejaculate? / Pode a suplementação mineral influenciar as características do ejaculado de touros búfalos jovens?

This study aimed to determine the influence of mineral supplementation on the concentration of macroelements and microelements in the seminal plasma and the semen characteristics of young buffaloes. To this end, 60 animals were kept under rotational grazing and were randomly divided into two groups: G-Bov (conventional mineral supplement recommended for bovine cattle; n = 30) and G-Buf (mineral supplement recommended for buffaloes; n = 30). Mineral supplement consumption was calculated from the difference between the amount of supplement offered and the leftover bunk, calculated every 28 days. Eight ejaculates from each animal were collected. The means of the response variables were analyzed using the Kruskal-Wallis test, with a significance level of 5%, and Pearson’s correlation was analyzed between the concentration of minerals in seminal plasma and fresh semen characteristics. Animals in the G-Buf group had lower mineral supplement consumption (G-Bov = 83.18 vs. G-Buf = 77.14 g AU-1 day-1, P < 0.05) and had higher ejaculate volume, sperm motility, sperm vigor, and sperm mass motility than did the animals in the G-Bov group. This research presented the concentration of macroelements and microelements in the seminal plasma of buffaloes receiving different mineral supplements. In addition, the study concluded that the physical and morphological characteristics of the semen of young buffaloes are influenced by the formulation of the mineral supplement, which resulted in better sperm quality in the animals receiving a species-specific supplement. Among the minerals present in buffalo seminal plasma, phosphorus is the element that shows the highest positive correlation with semen characteristics.

Com o objetivo de verificar a influência do suplemento mineral consumido na concentração dos macro e microelementos no plasma seminal e nas características do sêmen de búfalos, 60 bezerros de 10 meses de idade foram mantidos sob lotação intermitente por 14 meses, consumindo, ad libitum, dois suplementos minerais distintos e divididos aleatoriamente em dois grupos: G-Bov (suplemento mineral convencional recomendado para bovinos; n=30) e G-Buf (suplemento mineral específico para búfalos; n=30). O consumo do suplemento mineral foi calculado a partir da diferença entre a quantidade de suplemento oferecido e a sobra mensal do cocho. Dos búfalos a partir dos 22 meses de idade foram realizadas oito colheitas de sêmen de cada animal. As médias das variáveis foram analisadas por meio do teste de Kruskal-Wallis, com nível de significância de 5%, também foi analisada a correlação de Pearson entre a concentração de minerais no plasma seminal e as características do ejaculado. Observou-se que os animais do G-Buf mesmo consumindo menos suplemento mineral (G-Bov = 83,18 vs. G-Buf = 77,14 g UA-1 dia-1; P<0,05) obtiveram maior volume do ejaculado e melhores motilidade, vigor e turbilhonamento. Esta pesquisa apresenta as concentrações de macro e microelementos no plasma seminal de búfalos suplementados com diferentes formulações minerais. Além disso, concluiu-se que as características físicas e morfológicas do sêmen de búfalos jovens são influenciadas pelo tipo de suplementação mineral, apresentando sêmen de melhor qualidade em búfalos suplementados com suplementos específicos para a espécie. Dos minerais presentes no plasma seminal de búfalos, o fósforo é o elemento que mostra maior correlação positiva com as características seminais no ejaculado.

Challenges to increase the AI and ET markets in Brazil

Artificial insemination (AI) and embryo transfer (ET) are the most widely used biotechnologies in the world with the goal of increasing genetic gain and improving reproductive efficiency of beef and dairy herds. The protocols for ovulation synchronization for timed AI (TAI) or ET (TET) are tools that allow artificial insemination or transfer of a high number of embryos in a pre-established moment and without the necessity of estrous detection. Currently, 86% of inseminations in Brazil are performed using TAI (13.6 million TAI out of a total of 15.4 million doses of semen marketed in 2018). With the use of TAI, it was possible to verify that the percentage of artificially inseminated females in Brazil went from 5.8% in 2002 to 13.1% in 2018. The ET market also presented considerable growth in the last 20 years. There was an increase of approximately 8 fold in the number of produced embryos, escalating from 50,000 in 1999 to 375,000 in 2017. In this period, there was a significant increase on the in vitro embryo production, which represented 92.1% of embryos produced in Brazil in 2017. Also, in this period, there was an increase on the embryo production of dairy breeds and reduction on the embryo production of zebu breeds in comparison to data from the early 2000’s. TET increases significantly the number of recipients suitable to receive an embryo. After synchronization, 75 to 85% of recipients present a suitable CL for ET without estrous detection. Currently, many synchronization and resynchronization protocols for TAI/TET have been studied to attend different managements, breeds and animal categories, with predictable and satisfactory results. With the intensification of the use of these biotechnologies, it is possible to obtain elevated reproductive efficiency with increase on the genetic gain, which determines greater productivity and economic return for dairy and beef farms. However, the challenge to keep the market growing in the next decade could depend on some factors, such as: increase of the extension services for producers and of the extension training for specialists, improvement of the technological advances to develop more efficient and cost-effective products and practical protocols, increase the integration between universities, research institutes, veterinarians and industries and also, asses market demand for production of animal protein with higher quality, efficiency and environmental and economic sustainability.

Can mineral supplementation modify the characteristics of young buffalo ejaculate? / Pode a suplementação mineral influenciar as características do ejaculado de touros búfalos jovens?

This study aimed to determine the influence of mineral supplementation on the concentration of macroelements and microelements in the seminal plasma and the semen characteristics of young buffaloes. To this end, 60 animals were kept under rotational grazing and were randomly divided into two groups: G-Bov (conventional mineral supplement recommended for bovine cattle; n = 30) and G-Buf (mineral supplement recommended for buffaloes; n = 30). Mineral supplement consumption was calculated from the difference between the amount of supplement offered and the leftover bunk, calculated every 28 days. Eight ejaculates from each animal were collected. The means of the response variables were analyzed using the Kruskal-Wallis test, with a significance level of 5%, and Pearsons correlation was analyzed between the concentration of minerals in seminal plasma and fresh semen characteristics. Animals in the G-Buf group had lower mineral supplement consumption (G-Bov = 83.18 vs. G-Buf = 77.14 g AU-1 day-1, P < 0.05) and had higher ejaculate volume, sperm motility, sperm vigor, and sperm mass motility than did the animals in the G-Bov group. This research presented the concentration of macroelements and microelements in the seminal plasma of buffaloes receiving different mineral supplements. In addition, the study concluded that the physical and morphological characteristics of the semen of young buffaloes are influenced by the formulation of the mineral supplement, which resulted in better sperm quality in the animals receiving a species-specific supplement. Among the minerals present in buffalo seminal plasma, phosphorus is the element that shows the highest positive correlation with semen characteristics.(AU)

Com o objetivo de verificar a influência do suplemento mineral consumido na concentração dos macro e microelementos no plasma seminal e nas características do sêmen de búfalos, 60 bezerros de 10 meses de idade foram mantidos sob lotação intermitente por 14 meses, consumindo, ad libitum, dois suplementos minerais distintos e divididos aleatoriamente em dois grupos: G-Bov (suplemento mineral convencional recomendado para bovinos; n=30) e G-Buf (suplemento mineral específico para búfalos; n=30). O consumo do suplemento mineral foi calculado a partir da diferença entre a quantidade de suplemento oferecido e a sobra mensal do cocho. Dos búfalos a partir dos 22 meses de idade foram realizadas oito colheitas de sêmen de cada animal. As médias das variáveis foram analisadas por meio do teste de Kruskal-Wallis, com nível de significância de 5%, também foi analisada a correlação de Pearson entre a concentração de minerais no plasma seminal e as características do ejaculado. Observou-se que os animais do G-Buf mesmo consumindo menos suplemento mineral (G-Bov = 83,18 vs. G-Buf = 77,14 g UA-1 dia-1; P<0,05) obtiveram maior volume do ejaculado e melhores motilidade, vigor e turbilhonamento. Esta pesquisa apresenta as concentrações de macro e microelementos no plasma seminal de búfalos suplementados com diferentes formulações minerais. Além disso, concluiu-se que as características físicas e morfológicas do sêmen de búfalos jovens são influenciadas pelo tipo de suplementação mineral, apresentando sêmen de melhor qualidade em búfalos suplementados com suplementos específicos para a espécie. Dos minerais presentes no plasma seminal de búfalos, o fósforo é o elemento que mostra maior correlação positiva com as características seminais no ejaculado.(AU)

Challenges to increase the AI and ET markets in Brazil

Artificial insemination (AI) and embryo transfer (ET) are the most widely used biotechnologies in the world with the goal of increasing genetic gain and improving reproductive efficiency of beef and dairy herds. The protocols for ovulation synchronization for timed AI (TAI) or ET (TET) are tools that allow artificial insemination or transfer of a high number of embryos in a pre-established moment and without the necessity of estrous detection. Currently, 86% of inseminations in Brazil are performed using TAI (13.6 million TAI out of a total of 15.4 million doses of semen marketed in 2018). With the use of TAI, it was possible to verify that the percentage of artificially inseminated females in Brazil went from 5.8% in 2002 to 13.1% in 2018. The ET market also presented considerable growth in the last 20 years. There was an increase of approximately 8 fold in the number of produced embryos, escalating from 50,000 in 1999 to 375,000 in 2017. In this period, there was a significant increase on the in vitro embryo production, which represented 92.1% of embryos produced in Brazil in 2017. Also, in this period, there was an increase on the embryo production of dairy breeds and reduction on the embryo production of zebu breeds in comparison to data from the early 2000s. TET increases significantly the number of recipients suitable to receive an embryo. After synchronization, 75 to 85% of recipients present a suitable CL for ET without estrous detection. Currently, many synchronization and resynchronization protocols for TAI/TET have been studied to attend different managements, breeds and animal categories, with predictable and satisfactory results. With the intensification of the use of these biotechnologies, it is possible to obtain elevated reproductive efficiency with increase on the genetic gain, which determines greater productivity and economic return for dairy and beef farms. However, the challenge to keep the market growing in the next decade could depend on some factors, such as: increase of the extension services for producers and of the extension training for specialists, improvement of the technological advances to develop more efficient and cost-effective products and practical protocols, increase the integration between universities, research institutes, veterinarians and industries and also, asses market demand for production of animal protein with higher quality, efficiency and environmental and economic sustainability.(AU)

Evolução e perspectivas da inseminação artificial em bovinos / Evolution and perspectives of timed artificial insemination in cattle

A inseminação artificial (IA) em bovinos tem sido aplicada em todo o mundo com o intuito de melhorar o ganho genético e a eficiência reprodutiva dos rebanhos. Com o objetivo de facilitar a utilização da IA foram desenvolvidos protocolos de inseminação artificial em tempo fixo (IATF) que promovem o controle do crescimento folicular e da ovulação e permitem a aplicação da IA em dias predeterminados, sem a necessidade de detecção de estro e com elevadas taxas de prenhez. Nos últimos 20 anos, vários protocolos de sincronização para IATF foram estudados para atender diferentes realidades de manejo, raças e categorias de animais. Atualmente, 86% das inseminações no Brasil estão sendo realizadas por IATF (13,6 milhões de IATF de um total de 15,4 milhões de doses de sêmen comercializadas em 2018). Com a colaboração dessa tecnologia, verificou-se que o percentual de fêmeas em idade reprodutiva inseminadas artificialmente passou de 5,8% em 2002 para 13,1% em 2018. O aumento de uso da IATF representa considerável incremento de produtividade quando comparado com a monta natural, maximizando o retorno econômico para as fazendas de corte e de leite.

Artificial insemination in cattle has been used worldwide to improve the genetic gain and reproductive efficiency of the herds. In order to facilitate the use of AI, several protocols for timed artificial insemination (TAI) have been developed, which promote the control of follicular growth and ovulation, allowing the use of AI in predetermined days, without the necessity of estrus detection and with satisfactory pregnancy rates. In the last 20 years, a wide variety of protocols have been studied to address different management realities, breeds and animal categories. Currently, 86% of artificial inseminations in Brazil are performed using TAI (13.6 million TAI of 15.4 million batches of semen commercialized in 2018). The percentage of females in reproductive age inseminated in Brazil went from 5.8% in 2002 to 13.1% in 2018. Reproductive programs that use TAI present increase in productivity when compared to natural breeding, maximizing the economic gain for beef and dairy properties.

Genetic market in cattle (Bull, AI, FTAI, MOET and IVP): financial payback based on reproductive efficiency in beef and dairy herds in Brazil

A number of reproductive biotechnologies are currently available to multiply offspring from high genetic merit animals to enhance reproductive efficiency and profitability both in dairy and beef herds. Some of these technologies such as fixed time artificial insemination (FTAI), when correctly implemented,generally allow greater reproductive performance than natural breeding. Besides the use of frozen-thawed semen during artificial insemination, cattle recipients can also be synchronized to receive embryos (produced in vivo or in vitro) at set dates with fertility results that usually outperforms natural breeding as well as artificial insemination (AI), particularly during warm seasons and in repeat breeders cows. Altogether, the use of hormonal programs to synchronize ovulation time simplify field routine, can easily fix physiological limitations related to postpartum anestrus (beef cows), poor estrus detection efficiency due to less evident estrus signs (dairy cows), making AI and ET viable to commercial herds both in terms of results and economical returns.

Genetic market in cattle (Bull, AI, FTAI, MOET and IVP): financial payback based on reproductive efficiency in beef and dairy herds in Brazil

A number of reproductive biotechnologies are currently available to multiply offspring from high genetic merit animals to enhance reproductive efficiency and profitability both in dairy and beef herds. Some of these technologies such as fixed time artificial insemination (FTAI), when correctly implemented,generally allow greater reproductive performance than natural breeding. Besides the use of frozen-thawed semen during artificial insemination, cattle recipients can also be synchronized to receive embryos (produced in vivo or in vitro) at set dates with fertility results that usually outperforms natural breeding as well as artificial insemination (AI), particularly during warm seasons and in repeat breeders cows. Altogether, the use of hormonal programs to synchronize ovulation time simplify field routine, can easily fix physiological limitations related to postpartum anestrus (beef cows), poor estrus detection efficiency due to less evident estrus signs (dairy cows), making AI and ET viable to commercial herds both in terms of results and economical returns.(AU)

Uso da ultrassonografia Doppler em programas de IATF e TETF em bovinos / Use of Doppler ultrasonography in timed-AI and ET programs in cattle

O uso intensivo da ultrassonografia Doppler em diversos estudos na última década possibilitou acaracterização da perfusão sanguínea, e estimativa da funcionalidade nos órgãos e tecidos reprodutivos ao longodo ciclo estral e da gestação em bovinos. Objetiva-se aqui discutir as possibilidades de uso da ultrassonografiaDoppler, assim como explorar seu potencial de inclusão em programas reprodutivos em bovinos. Os estudosrecentes em vacas de leite e corte apontam uma alta acurácia e sensibilidade quando a ultrassonografia Doppler éempregada para avaliar a funcionalidade do corpo lúteo e diagnosticar a gestação aos 20-22 dias. Diante disso,programas de ressincronização super-precoce iniciados aos 14 dias pós-inseminação foram desenvolvidos emnovilhas e vacas de corte e estão sendo implementados em programas comerciais de IATF. Estas estratégiaspermitem uma redução para 24 dias no intervalo entre duas IATFs e podem promover ganhos na eficiênciareprodutiva comparado aos sistemas convencionais com diagnóstico da gestação aos 30 dias. Além disso, aavaliação da função luteal pela ultrassonografia Doppler possibilita a seleção de receptoras de embriões commaior receptividade, e consequentemente pode melhorar a fertilidade em programas de TETF.(AU)

The intensive use of Doppler ultrasonography in several studies in the last decade allowed thecharacterization of vascular perfusion, and the estimation of the function of the reproductive organs and tissuesalong the estrous cycle and pregnancy in cattle. We aimed to discuss the possibility of use Doppler imaging, asto explore the potential of its inclusion in reproductive programs in cattles industry. Recent studies in dairyand beef cows indicated a high accuracy and sensibility when Doppler ultrasonography is used to evaluate thefunction of corpus luteum and to diagnosis the pregnancy between days 20 and 22. Moreover,ressynchronization programs starting 14 days post-TAI were developed in beef heifers and cows, and are beenimplemented in commercial TAI programs. These strategies allow a reduction to 24 days in the interval betweentwo TAIs and may improve the gains in reproductive efficacy when compared to the traditional programs withpregnancy diagnosis at 30 days. In addition, the evaluation of luteal function by Doppler ultrasonographyallows the selection of embryo recipients with greater receptivity, and consequently may increase the fertility in timed embryo transfer programs.(AU)

Intrinsic and extrinsic factors that influence ovarian environment and efficiency of reproduction in cattle

The emergent concepts on ovary environment,reproductive physiology and the development ofpharmacology are constantly supporting the advance ofassisted reproduction. Within the last years, thebiotechnics related to the synchronization of folliculardevelopment and the manipulation of bovine estruscycle have progressed rapidly and consistently. Thecombined use of timed-artificial insemination (TAI),superovulation (SOV), ovum pick up (OPU), in vitroembryo production (IVEP) and timed-embryo transfer(TET) has a great potential to improve reproductiveoutcomes and disseminate selected genetics,diminishing the interval of generations and improvingherds genetic gain. However, several factors canpotentially affect the efficiency of these procedures. Theknowledge of the particularities of the genetic groups,follicular growth manipulation, follicular populationpredictors, and metabolic and environmental aspectsthat interfere with ovarian environment and,consequently, oocyte quantity and quality is crucial tooptimize the reproductive programs. This review aimsto elucidate some factors that affect the ovarianenvironment and must be well known in order toimprove the efficiency of reproduction in cattle.

Timed artificial insemination: current challenges and recent advances in reproductive efficiency in beef and dairy herds in Brazil

Beef and dairy productivity depends directly on the reproductive efficiency and genetic gain of the herd, which can be related to the appropriate use of biotechnologies, such as timed artificial insemination (TAI). When considering variations in synchronizations protocols, longer or shorter periods of progesterone (P4) device treatment could provide benefits to fertility. However, our studies evidenced that protocols with six (J-synch), seven, eight and nine days of P4 device treatment had similar pregnancy per AI (P/AI). In cyclic cows, the early prostaglandin (PGF) administration, moving from the day of P4 device removal to two days earlier, which results in four handlings of cows, or the administration of one extra dose of PGF at the onset of the protocol and a single PGF on the day of P4 device removal (three handlings) are both efficient to induce early luteolysis, reducing serum P4 concentrations and, therefore, stimulating LH pulsatility, which improves growth of the dominant follicle and results greater P/AI when compared with protocols with the administration of PGF only on the day of P4 device removal. Resynchronization is another valuable tool to reduce the interval between AI. Traditional Resynch is initiated at pregnancy diagnosis (28 to 32 days after TAI) and the interval between AI is around 40 days; Resynch 22 and Resynch 14 respectively initiates 22 and 14 days after the previous AI in all cows (unknown status of pregnancy) and reduces the interval between AI to 32 and 24 days. The novelty about Resynch 14 is the need to use of Doppler ultrasonography for pregnancy diagnosis [evaluation of corpus luteum (CL) vascularization].

Timed artificial insemination: current challenges and recent advances in reproductive efficiency in beef and dairy herds in Brazil

Beef and dairy productivity depends directly on the reproductive efficiency and genetic gain of the herd, which can be related to the appropriate use of biotechnologies, such as timed artificial insemination (TAI). When considering variations in synchronizations protocols, longer or shorter periods of progesterone (P4) device treatment could provide benefits to fertility. However, our studies evidenced that protocols with six (J-synch), seven, eight and nine days of P4 device treatment had similar pregnancy per AI (P/AI). In cyclic cows, the early prostaglandin (PGF) administration, moving from the day of P4 device removal to two days earlier, which results in four handlings of cows, or the administration of one extra dose of PGF at the onset of the protocol and a single PGF on the day of P4 device removal (three handlings) are both efficient to induce early luteolysis, reducing serum P4 concentrations and, therefore, stimulating LH pulsatility, which improves growth of the dominant follicle and results greater P/AI when compared with protocols with the administration of PGF only on the day of P4 device removal. Resynchronization is another valuable tool to reduce the interval between AI. Traditional Resynch is initiated at pregnancy diagnosis (28 to 32 days after TAI) and the interval between AI is around 40 days; Resynch 22 and Resynch 14 respectively initiates 22 and 14 days after the previous AI in all cows (unknown status of pregnancy) and reduces the interval between AI to 32 and 24 days. The novelty about Resynch 14 is the need to use of Doppler ultrasonography for pregnancy diagnosis [evaluation of corpus luteum (CL) vascularization].(AU)