The aim of the present work was to evaluate the breed and season effects on scrotal circumference (SC) and semen characteristics of 28 mature hair sheep rams kept under tropical conditions. SCs, sperm concentration (SPC) and abnormal sperm were significantly affected by breed effect (p < 0.001). The season effect was significant in SPC (p < 0.0001) while ejaculate volume, mass motility and SPC were affected by breed × season interaction effect (p< 0.001). It can be concluded that the magnitude of the breed and season effects were not sufficient to affect the reproductive capacity of hair sheep rams throughout the year.

The aim was to evaluate the effect of corn oil supplementation during postpartum anoestrus on ovarian activity, pregnancy rate, progesterone (P(4)), and lipid metabolites (cholesterol, CHO; low and high density lipoproteins; LDL and HDL, respectively) concentrations in blood of F(1) (Bos taurus x Bos indicus) grazing cows. Cows were randomly assigned to an experimental group, fed with a supplement containing 4% corn oil on dry matter basis (OG, n = 11), and a control group with the same supplement without corn oil (CG, n = 12). Both supplements contained equivalent amounts of crude protein and metabolizable energy and were fed for 34 days continuously. All cows were induced to estrous 12 days after beginning of supplementation by using a synthetic progestagen and artificially inseminated 56 h after retiring the implants. Pregnancy diagnosis was performed by transrectal palpation 45 days after insemination, evaluating simultaneously ovarian activity. P(4) and lipid metabolites (CHO, HDL, LDL) concentrations were determined in blood samples collected at 3-day intervals, from the beginning of corn oil supplementation and up to 10 days after artificial insemination. Ovarian activity was affected by treatment (p < 0.05), finding ovarian structures in 72.7% of OG cows and in 50% of CG cows. Concentration of P(4) and CHO was higher for OG with respect to CG (2.52 +/- 0.65 vs 1.88 +/- 0.62 ng/ml and 117.79 +/- 11.57 vs 85.71 +/- 12.11 mg/dl, respectively), whereas pregnancy rate and blood concentrations of HDL and LDL were not affected by treatment (p > 0.05). Addition of corn oil to the supplement stimulated ovarian activity and increased serum concentrations of progesterone and cholesterol in grazing B. taurus x B. indicus cows with low body condition score showing postpartum anoestrus.

The aims of this study were to evaluate the superovulatory response (SR), embryo quality and embryonic development in Katahdin ewes that received a dietary supplement of palm oil (PO). Ten ewes were assigned to receive 35 g palm oil (n = 10, PO3) and 10 to receive 70 g palm oil (n = 10, PO6) for 25 days. On day 0, the ewes were synchronized with 0.3 mg progesterone-releasing devices (CIDR-G®). From days 6 to 9, the donors were superovulated with 200 mg follicle-stimulating hormone (FSH) (Folltropin-V®) at decreasing doses every 12 hours (40 - 40, 30 - 30, 20 - 20 and 10 - 10 mg/ewe). On day 8, the devices were removed and donors were mated twice with fertile rams at 12-h intervals. Seven days after mating, the embryos were recovered and evaluated for their stage of development and quality grade (1 = excellent, 2 = good, 3 = bad and 4 = degenerated). In addition, on days 0, 7 and 15, blood samples were taken to determine cholesterol, triglycerides, insulin and insulin-Iike growth factor-1 (IGF-1) concentrations in serum blood. Using chi-square and t-tests, the superovulatory response (SR), ovulation rate (OR), total embryonic structures (TES), transferable embryos (TE), degenerated embryos (DEs) and developmental stage and quality were evaluated. No significant differences were observed between treatments for SR, OR, TES and TE variables or for cholesterol, triglycerides, insulin and IGF-1 concentrations. There were differences in the numbers of DE, as well as a trend for more homogeneous developmental stage in the embryos of ewes supplemented with PO6, as well as a higher number of quality 1 embryos and lower numbers of quality 3 and 4 embryos. Palm oil supplementation could be a recommendable practice to improve the quality of embryos and homogenous developmental stage (morula and blastocyst).Keywords: Fatty acids, ovarian activity, sheep

RESUMENEl objetivo fue caracterizar los perfiles de progesterona (P4) y 17β estradiol (E-17β) sanguí-neos de 11 hembras adultas de P. tajacu mantenidas en cautiverio. Las hembras estaban en presencia del macho pero separadas de éste mediante una malla. Las muestras sanguíneas se tomaron cada 6 días durante 3 meses. La estimación de hormonas esteroides se efectuó por radioinmunoanálisis en fase sólida. Los perfiles hormonales fueron graficados con respecto al tiempo para determinar la duración de cada ciclo ovárico y la cantidad de ciclos. Nueve hembras ciclaron y 2 no. La duración promedio del ciclo ovárico fue 26,8±4,8 días. La concentración media de P4 en la fase luteal fue 22,95±4,94 ng/mL, y durante la fase folicular 1,2±0,73 ng/mL (p<0,05). Los niveles de E-17β en la fase luteal fueron 6,89±2,79 pg/mL y 32,17±7,29 pg/mL en la fase folicular (p<0,05). La presentación de los ciclos ováricos fue variable, aunque la duración estuvo dentro de los rangos establecidos para esta especie en cautiverio. La sincronía de los perfiles hormonales de P4 y E-17β fue inversa durante el ciclo ovárico. SUMMARYThe objective was to characterize the levels of progesterone (P4) and 17β estradiol (E-17β) in blood of 11 Pecari tajacu adult females in captivity. The females were in the presence of males but separated by a wire mesh. Blood samples were taken every 6 days during 3 months. The estimation of the levels of the steroid hormones was carried out by radioimmunoassay in solid phase. Hormonal profiles were plotted against time, to determine the duration of each ovarian cycle and the number of cycles. Nine animals showed estrous cycle and 2 did not. The average duration of the ovarian cycle was 26.8±4.8 days. The average concentration of P4 in the luteal phase was 22.95±4.94 ng/mL, and during the follicular phase was 1.2±0.73 ng/mL (p<0.05). The levels of E-17β in the luteal phase were 6.89±2.79 pg/mL, and 32.17±7.29 pg/mL in the follicular phase (p<0.05). The presence of the ovarian cycles was variable, although the duration was within the range of values established for this species under captivity. The synchrony of the hormonal profiles of P4 and E-17β during the ovarian cycle was inverted. INTRODUCCIÓNEn el Pecari tajacu se ha reportado la duración del ciclo estral mediante el uso de citología vaginal y determinación de niveles de progesterona sanguínea (López, 1993;Mauget et al., 1997); los niveles de estradiol y progesterona en hembras gestantes (Mayor et al., 2004) y la precisión de la detección del estro y del estro posparto mediante el #Los autores agradecen a la Fundación Produce Yucatán, el apoyo económico para la ejecución de este proyecto.