Number and density of equine preantral follicles in different ovarian histological section thicknesses.

Regardless of species, advances in preantral follicle culture and cryopreservation and transplant of ovarian tissue techniques are dependent on the number and density of preantral follicles in the ovary. This study tested the effect of different histological section thicknesses on number, classification, and density of equine preantral follicles. An ovarian fragment was obtained from 5- to 10-year-old mares (n = 14) after slaughter, and each fragment was submitted to three histological section thickness treatments: 3, 5, and 7 µm. The area (cm(2)) of each ovarian fragment was measured, and the sections were evaluated by light microscopy. The percentage of morphologically normal follicles (89%) was similar (P > 0.05) among primordial, transitional, and primary follicles and also among histological section thicknesses. A greater (P < 0.05) number of preantral follicles per histological section were seen in the 7-µm (8.0 ± 2.2) than that in the 3-µm (3.4 ± 0.7) treatment. Furthermore, a linear regression analysis reported that the number of preantral follicles increased (P < 0.05) when a thicker section treatment was used. However, no association (P > 0.05) between follicular density and treatment was observed. The mean number of preantral follicles per fragment (45.3 ± 18.8) and the follicular density (3.0 ± 0.5 follicles per cm(2)) were different (P < 0.05) among mares. In conclusion, this study on equine preantral follicles reported that (1) a 7-µm histological section thickness might be recommended because it allowed identification of a greater number of preantral follicles per sample, (2) a large individual variation in follicle population and density was detected regardless of histological section thickness, and (3) mares have a low number and density of preantral follicles when compared with those reported for other species.

Electrocardiographic study in the American Quarter Horse breed / Estudo eletrocardiográfico de equinos da raça Quarto de Milha

An evaluation of the electrocardiographic profile of 50 clinically healthy Quarter Horses, with ages ranging from six months to 28 years old, 34 females and 16 males, was performed. Heart rate has not decreased with age, and duration of the QRS complex increased with the growth of the animal. The amplitude of the S and T1 waves were higher in male subjects than in female Quarter Horses.

Avaliou-se o perfil eletrocardiográfico de 50 equinos da raça Quarto de Milha, clinicamente sadios, com idades variando de seis meses a 28 anos, sendo 34 fêmeas e 16 machos. A frequência cardíaca não diminuiu com a idade, e a duração do complexo QRS aumentou ao longo do crescimento do animal. A amplitude das ondas S e T1 foram maiores nos indivíduos machos do que nas fêmeas da raça Quarto de Milha.

Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol.

The effects of estradiol benzoate (EB) and estradiol cypionate (EC) on induction of ovulation after a synchronized LH surge and on fertility of Bos indicus females submitted to timed AI (TAI) were evaluated. In Experiment 1, ovariectomized Nelore heifers were used to evaluate the effect of EB (n = 5) and EC (n = 5) on the circulating LH profile. The LH surge timing (19.6 and 50.5 h; P = 0.001), magnitude (20.5 and 9.4 ng/mL; P = 0.005), duration (8.6 and 16.5 h; P = 0.001), and area under the LH curve (158.6 and 339.4 ng/mL; P = 0.01) differed between the EB and EC treatments, respectively. In Experiment 2 (follicular responses; n = 60) and 3 (pregnancy per AI; P/AI; n = 953) suckled Bos indicus beef cows submitted to an estradiol/progesterone-based synchronization protocol were assigned to receive one of two treatments to induce synchronized ovulation: 1 mg of EB im 24 h after progesterone (P4) device removal or 1 mg of EC im at P4 device removal. There was no difference (P > 0.05) between EB and EC treatments on follicular responses (maximum diameter of the ovulatory follicle, 13.1 vs. 13.9 mm; interval from progesterone device removal to ovulation, 70.2 vs. 68.5 h; and ovulation rate, 77.8 vs. 82.8%, respectively). In addition, P/AI was similar (P < 0.22) between the cows treated with EB (57.5%; 277/482) and EC (61.8%; 291/471). In conclusion, despite pharmacologic differences, both esters of estradiol administered either at P4 device removal (EC) or 24 h later (EB) were effective in inducing an LH surge which resulted in synchronized ovulations and similar P/AI in suckled Bos indicus beef cows submitted to TAI.

Desenvolvimento morfológico dos ovários em embriões e fetos bovinos da raça Nelore / Morphological development of the ovaries in embryos and fetuses of Nelore breed

Investigaram-se os eventos morfológicos relacionados ao desenvolvimento pré-natal de ovários de 81 embriões e fetos da raça Nelore, coletados em frigoríficos, com idades variando de 26 a 240 dias pós-fecundação. Observou-se formação da crista gonádica e presença de células germinativas em seu interior aos 29 e 34 dias, respectivamente. As oogônias e folículos primordiais, ao contrário dos folículos em crescimento, apresentaram diferenças significativas de diâmetro nos vários períodos estudados. Verificou-se correlação positiva (P<0,05) entre o diâmetro das oogônias e de seus núcleos, bem como entre o diâmetro dos folículos primordiais e em crescimento com seus oócitos e respectivos núcleos. A gônada apresentou-se completamente formada aos 40 dias. Folículos primordiais, em crescimento e antrais surgiram, aproximadamente, aos 95, 140 e 180 dias, respectivamente. Na raça Nelore, a oogênese tem início e duração semelhante à de raças taurinas, mas apresenta como peculiaridade a antecipação do surgimento da foliculogênese.

Hepatozoon canis (James, 1905) em cäes de Uberlândia, Minas Gerais. Relato de dois casos / Hepatozoon canis (James, 1905) in dogs from Uberlandia, Minas Gerais. Reports of two cases

Gametócitos de Hepatozoon canis, medindo 9,56 um x 5,60 um, foram identificados no citoplasma de leucócitos circulantes de dois cäes atendidos no Hospital Veterinário da Universidade Federal de Uberlândia. Essa hemoparasitose ocorreu associada à infecçäo por E. canis. É relatada a primeira ocorrência do H. canis em Uberlândia, Minas Gerais