Sperm subpopulations influence the pregnancy rates in cattle.

This study aimed to study the characteristics and subpopulations of spermatozoa from bulls with low and high reproductive performance based on pregnancy rates. Based on historical records of pregnancy rate from four farms, 24 bulls were selected. Two groups were established, with low pregnancy rates (n = 12; LOW), including bulls that presented pregnancy rates <52.27% (33.33% to 51.81%); and a group with high pregnancy rates (n = 12; HIGH), with pregnancy rates >52.27% (52.27% to 69.64%), after fixed-time artificial insemination (FTAI). The thawed sperm straws were analysed to sperm kinetics, morphology, plasma membrane integrity and sperm subpopulations. The LOW group exhibited a higher proportion of static cells (p < .05). In contrast, the HIGH group showed greater percentages for membrane integrity and total and progressive motility, and cells with fast and medium velocity (p < .05). In the cluster procedures, four sperm subpopulations were established. The low-fertility bulls presented the highest percentage of subpopulation 2 (41.46%), characterized by slow and progressive spermatozoa. The high-fertility bulls exhibited the highest percentage of subpopulation 3 (37.17%), characterized by fast and nonlinear spermatozoa. Results from this study indicated that bulls with greater percentages of fast and nonlinear spermatozoa seem to have greater fertilization capacity and the subpopulations analysis can be considered a tool to identify ejaculates with high fertility.

In vitro culture supplementation of EGF for improving the survival of equine preantral follicles.

Folliculogenesis is a process of development and maturation of the ovarian follicles, being essential for the maintenance of fertility. In in vivo conditions, 99.9% of the follicles of an ovary do not ovulate and undergo atresia. In order to minimize this loss and to clarify the existing mechanisms, a technique was developed that allows for the in vitro follicular development. The objective of this study was to evaluate the effects of different epidermal growth factor (EGF) concentrations on the in vitro culturing of equine preantral follicles. Ovaries (n = 10) were collected from a local slaughterhouse of mares in seasonal anestrus, washed with 70% alcohol and PBS, and transported. The inner portion of the ovary was divided into 11 fragments of approximately 3 × 3 × 1 mm. A fragment of each ovary was immediately fixed in Bouin (control group). The remaining 10 fragments were individually cultured for 2 and 6 d. The medium was supplemented with different concentrations of EGF (0, 10, 50, 100, and 200 ng/mL). After cultivation, the fragments were processed and classified according to the developmental stage and morphology. In total, 1065 slides containing 6105 tissue sections were evaluated. Within 2 d of culture, there was a higher proportion of intact follicles at the EGF concentrations of 0 and 100 ng/mL (p > 0.05). After 6 d of culture, only the EGF concentration of 100 ng/mL demonstrated a difference when compared to the other treatments (0, 10, 50 and 200 ng/mL of EGF, p > 0.05). There was follicular development after 2 d at all EGF concentrations. Thus, we suggest that EGF promotes follicular survival in equines at a concentration of 100 ng/mL in in vitro cultures of ovarian fragments for 2 d. In addition, we suggest that EGF promotes follicular survival in equines at a concentration of 100 ng/mL in situ cultivation.

Injectable progesterone in timed artificial insemination programs in beef cows.

The aims of this study were I) to compare the follicular diameter, corpus luteum diameter and serum progesterone (P4) concentrations in cows treated with conventional protocol vs. injectable P4 protocol; II) to determine the serum P4 profile in ovariectomized heifers; and III) to compare pregnancy rate between protocols. In experiment I, multiparous cows received a protocol for ovulation synchronization with an intravaginal P4 device (n = 38; device + EB day 0; device removal + PGF2α + eCG + EC day 8) or injectable P4 (n = 38; injection + EB day 0; PGF2α + eCG + EC day 8). In experiment II, ovariectomized heifers (n = 8) were treated with injectable P4 and blood samples were collected to determine the serum P4 profile. In experiment III, multiparous cows were timed AI with two different P4 approaches, intravaginal P4 device (n = 48) or injectable P4 (n = 47). In the first experiment, cows treated with P4 device had higher (P < 0.05) diameter of dominant follicle after ovulation induction (11.6 ± 1.8 vs.10.3 ± 1.8 mm) and ovulation rate (97%, 37/38 vs. 47.3%, 18/38) than cows treated with injectable P4. But, the follicular growth daily was higher (P < 0.05) in cows treated with injectable P4 than intravaginal device (1.3 ± 0.4 vs. 1.0 ± 0.3 mm/day, respectively). In experiment II, the P4 concentration peak occurred within 48 hours (6.54 ng/mL) and decreased after 96 hours (P < 0.05) after P4 injection. In experiment III, cows with P4 device had higher (P < 0.05) pregnancy rate than the injectable P4 group (60.4 vs. 34.0%, respectively). These results demonstrate that although the intravaginal P4 devices showed a higher pregnancy rate, a protocol with injectable P4 represents an easier method and a promising alternative for TAI in cattle.

High numbers of antral follicles are positively associated with in vitro embryo production but not the conception rate for FTAI in Nelore cattle.

The objective was to compare the conception rates for FTAI and in vitro embryo production between Nelore cows with different antral follicle counts (AFC=number of follicles ≤3mm in diameter in the ovaries). Nelore cows (n=547) were subjected to ovulation synchronization. Randomly during the estrous cycle (D0), cows received an intravaginal device containing 1.9g P4 (CIDR(®)) and 2mg BE (Estrogin(®)), IM. When the device was removed (D8), the cows received 500µg PGF2α (Ciosin(®)), 300IU eCG (Novormon(®)) and 1mg EC (ECP(®)), IM. All cows were inseminated 48h after P4 device removal. Antral follicles ≥3mm were counted using an intravaginal microconvex transducer (D0), and the cows were assigned to high (G-High, ≥25 follicles, n=183), intermediate (G-Intermediate, 16-20 follicles, n=183) or low AFC groups (G-Low, ≤10 follicles, n=181). In another experiment, COCs were retrieved by OPU from Nelore cows (n=66), which were assigned to groups according to oocyte production: G-High (n=22, ≥40 oocytes), G-Intermediate (n=25, 18-25 oocytes) or G-Low (n=19, ≤7 oocytes). All COCs from the same cow were cultured individually (maximum of 25 COCs per drop) and then in vitro fertilized using thawed frozen sperm (2×10(8)/dose) from a Nelore sire of known fertility. The data were analyzed using a Kruskal-Wallis and a Chi-square test (P≤0.05). There was no difference in the conception rates after FTAI between Nelore cows with high, intermediate or low AFC (51.9 vs. 48.6 vs. 58.6%). The number of viable embryos was 18.4±6.7 (G-High), 6.1±3.6 (G-Intermediate) and 0.6±0.7 (G-Low; P<0.05). Therefore, AFC had no influence on the conception rates for FTAI; however, Nelore cows with high oocyte production exhibited better in vitro embryo production.

Parâmetros obtidos no exame andrológico de touros da raça bonsmara / Parameters obtained on andrologic examination of bonsmara bulls

Objetivou-se com este estudo demonstrar os resultados obtidos no exame andrológico de touros da raça Bonsmara e classificá-los por meio da Classificação Andrológica por Pontos (CAP). Foram utilizados 39 touros da raça Bonsmara, criados extensivamente, com idade entre 33 a 74 meses. Os animais foram submetidos ao exame clínico geral, exame interno e externo do sistema genital, medições da circunferência escrotal e coleta do sêmen por meio de eletroejaculação, para avaliação das características físicas e morfológicas. Os resultados foram submetidos à análise estatística descritiva. Os valores médios obtidos para circunferência escrotal, motilidade espermática e vigor, foram respectivamente 40,96 ± 3,06 cm, 63,08 ± 23,41 % e 2,92 ± 0,98 (0-5) e os encontrados para defeitos espermáticos maiores e totais foram 4,25 ± 4,29 % e 21,10 ± 12,49 %. A média da Classificação Andrológica por Pontos (CAP) de 78,88 ± 18,19 (0-100) foi considerada satisfatória.

The objective of this study was to demonstrate the results obtained on andrologic examination and Andrologic Points Classification (CAP) of Bonsmara bulls. 39 Bonsmara bulls raised extensively, with ages between 33 and 74 months were submitted to general clinical examination, internal and external examination of the genital system, measurement of scrotal circumference and semen collection by electroejaculation for the evaluation of physical and morphological seminal characteristics. The results were submitted to the descriptive statistical analysis. The average values for scrotal circumference, sperm motility and vigor were respectively 40.96 ± 3.06 cm, 63.08 ± 23.41 % and 2.92 ± 0.98 (0-5) and those found for higher defects and total sperm were 4,25 ± 4.29 % and 21.10 ± 12.49 %. The average for Andrologic Points Classification (CAP) 78.88 ± 18.19 (0-100) was considered satisfactory.

Enzootic bovine leucosis ­ a case report / Leucose enzoótica bovina ­ relato de caso

Enzootic bovine leucosis is an infectious disease of cattle caused by the bovine leukemia virus that results in lymphoma within target tissues. Cattle might demonstrate four clinicopathological age-related manifestations of the disease: juvenile, adult, thymic, and cutaneous form. This article describes the unusual manifestation of this disease in a 4-yr-old cow. Regional lymph nodes were enlarged during clinical examination. Peripheral and internal lymph nodes, as well as the vagina, uterus, spleen, liver, heart, thoracic vertebrae, eye and the thoracic and abdominal cavities demonstrated lymphoma at necropsy. Bovine enzootic leucosis was confirmed by histopathology and agar gel immunodifusion.

A leucose enzoótica bovina é uma doença infecciosa de bovinos causada pelo vírus da leucemia bovina que produz linfoma em tecidos alvos. Bovinos podem demonstrar quatro manifestações clínico-patológicas da doença relacionadas à idade: forma juvenil, adulta, tímica e cutânea. Esse artigo descreve a manifestação incomum dessa doença em uma vaca de quatro anos de idade. Os linfonodos regionais apresentaram-se aumentados no exame clínico. Linfoma foi observado nos linfonodos periféricos e internos bem como na vagina, útero, baço, fígado, coração, vértebras torácicas, olho e nas cavidades torácica e abdominal durante a necropsia. A leucose enzoótica bovina foi confirmada na histopatologia e pela imunodifusão em gel de ágar.

Comparação das taxas de prenhez entre receptoras com corpos lúteos cavitários ou compactos após protocolo de sincronização com cloprostenol ou transferência de embriões em tempo fixo / Comparison tge pregnancy rates between bovine recipients with cavitary or compact corpus luteum after cloprostenol or fixed time embryo transfer

O objetivo deste experimento foi avaliar as taxas de prenhez em receptoras com corpo lúteo (CL) compacto ou cavitário, submetidas a protocolos com cloprostenol ou transferência em tempo fixo. Foram utilizadas 203 novilhas mestiças. No primeiro grupo (G-PGF, n=103), os animais com CL previamente detectados por ultra-sonografia transretal receberam 500mg de Cloprostenol (Sincrocio, Ouro fino, Brasil), por via IM e permaneceram sob observação de cio por 72 horas. No segundo grupo (G-P4, n=100), as novilhas receberam um dispositivo intravaginal de progesterona (CIDR, Pfizer, Brasil) simultaneamente à aplicação IM de 2 mg de benzoato de estradiol (BE); (Estrogin, Farmavet, Brasil). No oitavo dia, os dispositivos foram retirados e os animais receberam 500 mg de Cloprostenol (Sincrocio, Ouro fino, Brasil) por via IM. Após 24 horas, os animais receberam uma aplicação IM de 1 mg de BE. A avaliação ultra-sonográfica do CL foi realizada 10 dias e 17 dias após o início dos tratamentos, respectivamente para os grupos G-PGF e G-P4. Todas as receptoras com CL receberam embriões produzidos in vitro. O diagnóstico de gestação foi realizado 23 dias depois, por ultra-sonografia. Os resultados foram analisados pelo testo do Qui-quadrado. Não houve diferença significativa nas taxas de aproveitamento de receptoras entre os grupos G-PGF e G-P4 (72,8; 75/103; 79; 79/100). Detectou-se CL cavitário em 21,3 (16/75) das receptoras do G-PGF e 22,7 (18/79) para o grupo G-P4 (P>0,05). Entre as receptoras com CL cavitário ou compacto, não houve diferença na taxa de prenhez 41,1 (14/34) e 38,3 (46/120), respectivamente. Os resultados demonstraram que não houve diferença nas taxas de prenhez de receptoras com corpos lúteos cavitários, em comparação às receptoras com CL compactos, independentemente dos tratamentos realizados.

The aim of this work was to evaluate pregnancy rates in bovine embryo recipients with compact andcavitary corpus luteum. Two hundred and three crossbred heifers were divided in two groups. In the firstgroup (G-PGF, n=103), the animals received 500 mg de Cloprostenol IM (Sincrocio, Ouro fino, Brasil) afterCL identification by ultrasonography. After that, heifers were detected for heat the next 72 hours. Theanimals from second group (G-P4, n=100) received an intravaginal progesterone device (CIDR, Pfizer,Brasil) and 2 mg estradiol benzoate (Estrogin, Farmavet, Brasil) IM, in random stages from estrus cycle.On the 8th day the devices were removed and the animals received 500 mg of Cloprostenol IM. After 24hall animals received 1 mg BE, IM. The CL was identified and evaluated at 10 and 17 days after thebeginning of the treatmentin G-PGF and G-P4, respectively. All the heifers with CL received IVP embryos.The pregnancy diagnosis was made by transrectal ultrasonography after 23 days. The results wereanalyzed by Chi-square. There were no significant difference in number of heifers ready to embryotransfer in G-PGF and G-P4, respectively 72.8% (75/103) e 79% (79/100); (P>0.05)Twenty one percent (16/75) had cavitary CL in G-PGF and 22.7% (18/79) in G-P4 (P>0.05). Among all embryo recipients with acavitary or compact CL there was no difference on pregnancy rates(41.1% 14/34 and 38.3% 46/120,respectively, P>0.05), regardless of protocol treatment