Influence of preovulatory estradiol treatment on the maintenance of pregnancy in beef cattle receiving in vivo produced embryos.

This experiment was designed to determine the role of preovulatory estradiol in pregnancy retention after embryo transfer (ET). Cows were synchronized with the 7-d CO-Synch + CIDR® protocol. On d0 (d-2 =CIDR® removal), cows were grouped by estrual status (estrual [Positive Control] and nonestrual), and nonestrual cows were administered Gonadotropin Releasing Hormone (GnRH) and randomly assigned to either no treatment (Negative Control) or Estradiol (0.1 mg estradiol 17-ß IM). All cows received an embryo on d7. Pregnancy status was retrospectively classified on d56, 30, 24, and 19 by either ultrasonography, plasma pregnancy-associated glycoproteins analysis (PAGs), expression of interferon-stimulated genes, plasma progesterone (P4) concentrations, or a combination of the factors. There was no difference in estradiol concentrations on day 0 h 0 (P > 0.16). At day 0 h 2, Estradiol cows (15.7 ± 0.25 pg/mL) had elevated (P < 0.001) estradiol compared with Positive Controls (3.4 ± 0.26 pg/mL) or Negative Controls (4.3 ± 0.25 pg/mL). On d19, pregnancy rates did not differ (P = 0.14) among treatments. On d24, Positive Controls (47%) had greater (P < 0.01) pregnancy rates than Negative Controls (32%); Estradiol cows were intermediate (40%). There was no difference (P = 0.38) in pregnancy rates between Positive Control (41%) and Estradiol (36%) cows on d30, but Negative Control (27%) cows had (P = 0.01) or tended (P = 0.08) to have decreased pregnancy rates, respectively. Thus, preovulatory estradiol may elicit an effect on early uterine attachment or alter histotroph components, consequently improving pregnancy maintenance through d30.

Short communication: Reproduction outcomes in dairy heifers following a 14-d progesterone insert presynchronization protocol.

The objectives were to evaluate pregnancy per artificial insemination (AI), days to first AI, and proportion pregnant within 7 d of AI eligibility in dairy heifers subjected to presynchronization compared with dairy heifers not presynchronized. Thirty days before AI eligibility, Holstein heifers were assigned randomly to 1 of 3 groups: 14-d controlled internal drug release (CIDR; containing progesterone) presynchronization, PGF2α presynchronization, or control (no presynchronization). Heifers in the 14-d CIDR presynchronization treatment (n = 119) received a CIDR on d -30, which was removed on d -16, followed by an injection of PGF2α upon entry to the breeding program (d 0). Heifers in the PGF2α presynchronization treatment (n = 118) received an injection of PGF2α on d -11 and d 0. Control heifers (n = 121) were not presynchronized and received an injection of PGF2α on d 0. All heifers received tail paint on d 0 to facilitate once-daily detection of estrus (based on paint removal). Heifers detected in estrus received AI with conventional semen on the same morning as detected estrus. Generalized linear mixed models were used to assess mean treatment differences. Following PGF2α treatment on d 0, more heifers were detected in estrus in the first 7 d after eligibility in the 14-d CIDR group (95.8%) compared with the PGF2α (74.6%) and control (66.9%) groups. Days to first AI differed between treatments (14-d CIDR = 3.6 d vs. PGF2α = 5.0 d vs. control = 6.8 d). Pregnancy per AI for first AI within 7 d of eligibility was 71.9% (14-d CIDR), 58.0% (PGF2α), and 61.7% (control), and differed between 14-d CIDR and PGF2α heifers. Presynchronization with a 14-d CIDR increased the proportion of heifers pregnant in the first 7 d of eligibility (14-d CIDR = 68.9% vs. PGF2α = 43.2% vs. control = 41.3%). Projected days on feed (d 0 to projected calving date) were 295 (14-d CIDR), 302 (PGF2α), and 305 (control), and were different between the 14-d CIDR and control heifers. The potential economic benefit to the producer was $15.85 per heifer presynchronized with a 14-d CIDR protocol compared with the control group. Treatment of dairy heifers with a 14-d CIDR effectively presynchronized estrus, resulting in a greater proportion detected in estrus, reduced days to first AI, and an increased proportion of heifers pregnant within the first 7 d after breeding eligibility compared with heifers presynchronized with a single PGF2α injection and control heifers.

Comparison of three different extenders on Murrah buffaloes (Bubalus bubalis) semen freezability.

The use of frozen semen for artificial insemination is the main approach utilised for the genetic improvement of most domesticated species. The advantages include lower transportation costs, continuous availability of semen, fewer occurrences of sexually transmitted diseases and the incorporation of desirable genes in a relatively short amount of time. Nevertheless, the use of frozen semen in buffalo herds remains limited due to the loss of sperm quality when buffalo semen is frozen. So, the goal of this study was to evaluate the pre- and post-cryopreservation quality of buffalo semen diluted in three distinct freezing media: Tris-egg yolk, Botu-bov® (BB) and ACP-111®. Thirty-two ejaculates from four bulls were analysed in terms of kinetics, morphology and sperm viability by epifluorescence microscope. Thawed samples were also evaluated for capacitation-like damage, DNA fragmentation and plasma and acrosomal membrane integrity using flow cytometry. The Tris-egg yolk and BB® extenders yielded better results than the ACP-111® extender for kinetics parameter (total motility, progressive motility and percentage of rapid cells). However, semen samples were similar for parameters evaluated by flow cytometry. Taken together, the data indicate that in comparison with Tris-egg yolk and BB extender, ACP-111® can also be used as an extender for buffalo semen cryopreservation.

Morphological aspects of spermatogenic cells at different stagesof sexual maturation in black isogenic C57BL/6/Uni mice / Aspectos morfológicos de células de la espermatogénesis en diferentes etapas de maduración sexual del ratón negro isogénico C57BL/6/Uni

In order to study the morphological changes that occur in cells of the testes of isogenic black mouse C57BL/6/Uni into three periods during spermatogenetic used 15 mice divided into 3 groups of 5 animals with 40, 50 and 60 days of age. The mice were sacrificed and weighed. Testicles were weighed and measured, and histologically processed and stained with HE, PAS and Masson Massom-H and evaluated under light microscopy. It was observed that group I with 40 days of age in the seminiferous tubules had a lumen with sparse small amount of interstitial tubular cells. In the seminiferous epithelium type A spermatogonia, intermediate and B were identified, which occupied the compartment adbasal and intermingled with these cells in spermatocytes I in Pachytene and leptotene was observed, whereas in the adluminal compartment Golgi phase spermatids we observed the presence of acrosomal granule. In group II, the cells of the seminiferous epithelium were developed and it was observed in round spermatids cephalic hood phase plus many elongated spermatids in acrosome phase and Sertoli cells. In group III, 60 days old, it was found that seminiferous epithelium which was of the tubules had elongated spermatids in acrosome phase and maturation, with elongated nuclei and acrosomal system typical of spermiation in the presence of sperm and residual bodies near the tubular lumen. Therefore morphological evolution of germ cell testicular spermatids can be checked and recognized in its four phases: golgi, cap, acrosome and maturation over the age of the animal.

Con el fin de estudiar los cambios morfológicos que ocurren en las células de los testículos del ratón negro isogénico C57BL/6/Uni en tres períodos durante el proceso espermatogenético, se utilizaron 15 ratones divididos en 3 grupos de 5 animales con 40, 50 y 60 días de edad. Los ratones fueron sacrificados y pesados. Luego se pesaron y midieron los testículos, para ser finalmete procesados histológicamente y teñidos con HE, PAS y tricrómico Massom-H y evaluados bajo microscopía de luz. Se observó en el grupo I con 40 días de edad que los túbulos seminíferos tenían un lumen pequeño con escaza cantidad de células tubulares intersticiales. En el epitelio seminífero se identificaron espermatogonias tipo A, intermedio y B, que ocuparon el compartimiento adbasal y entremezcladas con estas células, se observó los espermatocitos I en paquiteno y leptoteno, mientras que en el compartimiento adluminal se observaron espermátidas de fase Golgi en presencia de gránulos acrosomales. En el grupo II, las células del epitelio seminífero se desarrollaron y fue posible observar espermátidas redondas en fase de capuz cefálico además de numerosas espermátidas elongadas en fase acrosómica y células sustentaculares. En el grupo III, de 60 días de edad, se encontró que el epitelio seminífero que revestía los túbulos presentaban espermátidas alargadas en fase acrosómica y de maduración, con sus núcleos alargados y el sistema acrosomal típico de la espermiación, con la presencia de espermatozoides y cuerpos residuales cerca del lumen tubular. Así, se puede comprobar con el paso de la edad del animal, la evolución morfológica de las células germinativas testiculares y reconocer las espermátidas en sus cuatro fases: golgi, capuchón, acrosomal y de maduración.

Morphological aspects of spermatogenic cells at different stages of sexual maturation in black isogenic C57BL/6/Uni Mice / Aspectos morfológicos de las células de la espermatogénesis en diferentesetapas de maduración sexual del ratón negro C57BL/6/Uni

In order to study the morphological changes that occur in cells of the testes of isogenic black mouse C57BL/6/Uni into three periods during spermatogenetic used 15 mice divided into 3 groups of 5 animals with 40, 50 and 60 days of age. The mice were sacrificed and weighed. Then weighed and measured the testicles, to be processed finalmete histologically and stained with HE, PAS and Masson Massom-H and evaluated under light microscopy. Was observed in group I with 40 days of age in the seminiferous tubules had a lumen with sparse small amount of interstitial tubular cells. In the seminiferous epithelium were identified type A spermatogonia, intermediate and B, which occupied the compartment adbasal and intermingled with these cells was observed in spermatocytes I in Pachytene and leptotene, whereas in the adluminal compartment Golgi phase spermatids observed in the presence of acrosomal granule. In group II, the cells of the seminiferous epithelium were developed and it was observed in round spermatids cephalic hood phase plus many elongated spermatids in acrosome phase and Sertoli cells. In Group III, 60 days old, it was found that the seminiferous epithelium which was of the tubules had elongated spermatids in acrosome phase and maturation, with elongated nuclei and acrosomal system typical of spermiation in the presence of sperm and residual bodies near the tubular lumen. So you can check the morphological evolution of germ cell testicular spermatids and recognize its four phases: Golgi, cap, acrosome and maturation over the age of the animal.

Con el fin de estudiar los cambios morfológicos que ocurren en las células del testículo del ratón negro isogénico C57BL/6/Uni en tres períodos diferentes del proceso espermatogenético; fueron utilizados 15 ratones divididos en 3 grupos (n=5) con 40, 50 y 60 días de edad respectivamente. Todos los animales fueron sacrificados y pesados. Posteriormente sus testículos se pesaron, midieron y procesaron histológicamente para HE, PAS y tricrómico Massom-H. Las muestras obtenidas fueron evaluados con microscopía de luz. En el grupo I con 40 días se observaron túbulos seminíferos con un lúmen pequeño y escaza cantidad de células intersticiales. En el epitelio seminífero se identificaron espermatogonias tipo A, intermedio y B, quienes ocuparon el compartimiento basal entremezclándose con espermatocitos I en paquiteno y leptoteno. En el compartimiento adluminal se observaron espermatidas de fase Golgi y presencia de gránulos acrosomales. En el grupo II de 50 días, se observaron células del epitelio seminífero desarrolladas, espermatidas en fase de capuz cefálico, muchas espermatidas elongadas en fase acrosomica y células sustentaculares. En el Grupo III de 60 días se observó el epitelio del túbulo seminífero con espermátidas alargadas en fase acrosómica y de maduración, con núcleos alargados y un sistema acrosomal típico de la espermiación, con presencia de espermatozoides y cuerpos residuales cerca del lúmen tubular. En conclusión se observa la evolución morfológica de las células germinativas testiculares y se reconocen las espermatides en sus cuatro fases: Golgi, capuchón, acrosomal y de maduración en las diferentes edades del animal.