Comparison between the 5-day cosynch and 7-day estradiol-based protocols for synchronization of ovulation and timed artificial insemination in suckled BOS taurus BEEF cows

The objective was to compare pregnancy per AI and follicular dynamic in suckled Bos taurus beef cows treated with either a 7-day progesterone + estradiol-based protocol or a 5-day progesterone CoSynch protocol for timed artificial insemination (TAI) during four breeding seasons. We hypothesized that estrous cycle status, days postpartum (DPP), fat depth and plasma progesterone concentration differentially modify the effect of treatments. Every year, 9 days before initiation of each breeding season, cows were randomly assigned to one of two groups. Cows in the 7-d P + E group (n = 428) received a progesterone intravaginal device (DIB) and estradiol benzoate on Day −9. On Day −2 the device was removed, and cows received cloprostenol and estradiol cypionate. Forty-eight hours later (Day 0) cows received TAI. Cows in the 5-d P + CoS group (n = 428) received a DIB, and GnRH on Day −8. On Day −3, the device was removed, and cows received cloprostenol. A second dose of cloprostenol was given on Day −2. Cows received GnRH and TAI 72 h after device removal (Day 0). On Day −9, estrous cycle status was determined. In a subset of cows (n = 79) the size of the dominant follicle was determined between Days −2 and 0. In another subset of cows (n = 340), DPP, fat depth (mm) and plasma progesterone concentration (ng/mL) were evaluated on Day −9. Pregnancy per AI was determined 30 d after TAI. Pregnancy per AI was greater for cows in the 5-d P + CoS group than for cows in the 7-d P + E group (50.9% vs. 41.3%, P = 0.01) and was also greater in cyclic than in anestrus cows (54.3% vs. 33.2%, P < 0.0001). There was also a significant effect of breeding season (P = 0.0002) and sire (P = 0.03), and an interaction between treatment group and breeding season (P = 0.03). The dominant follicle was larger (P < 0.0001) in cows in the 5-d P + CoS group than the 7-d P + E group (10.7 ± 0.29 mm vs. 9.0 ± 0.28 mm). Pregnancy per AI was greater in cows with ≥55 DPP (47.0% vs. 29.6%, P = 0.001), fat depth ≥0.50 mm (44.7% vs. 29.7%), and with plasma progesterone concentration ≥1 ng/mL (47.2% vs. 28.7%, P = 0.01). In cows with plasma progesterone ≥1 ng/mL on Day −9, pregnancy per AI was greater in the 5-d P + CoS group (60.5%) than in the 7-d P + E group (34.9%), but there was no difference between treatment groups in cows with plasma progesterone < 1 ng/mL (P = 0.07). In conclusion, the 5-d P + CoS protocol resulted in greater size of the dominant follicle and pregnancy per AI in suckled Bos taurus beef cows subjected to TAI.Fil: Bilbao, María Guillermina. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Zapata, Luis Oscar. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Romero Harry, H.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Perez Wallace, S.. Zoetis SRL; ArgentinaFil: Farcey, Maria Florencia. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Gelid, Lucas Fernando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; ArgentinaFil: Palomares, R. A.. University of Georgia. College of Veterinary Medicine; Estados UnidosFil: Ferrer, M. S.. University of Georgia. College of Veterinary Medicine; Estados UnidosFil: Bartolome, Julian. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentin

Caracterización de la incidencia de anestro posparto, intervalo días posparto a primer servicio y tasa de pérdida de preñez en dos tambos comerciales de la región pampeana

La fertilidad de los rodeos lecheros está condicionada por varios factores, entre ellos: i) estrés calórico, ii) producción de leche, iii) número de parición, iv) fertilidad de los toros, v) enfermedades de la transición y vi) confort y manejo del rodeo. El objetivo de este trabajo fue caracterizar la incidencia de anestro posparto, intervalo parto a primer servicio y pérdidas de gestación a lo largo del año en rodeos lecheros del Noreste de La Pampa. Para ello, se utilizaron datos de dos tambos comerciales: i) el Tambo 1, de elevada producción lechera (9700 litros promedio) con 1274 vacas totales; y ii) el Tambo 2 de mediana producción (7500 litros promedio) con 2550 vacas totales. Para cada vaca, se registró el número de pariciones (primípara o multípara), producción de leche (litros de leche en 305 días), estado (preñada, vacía, inseminada, rechazo), fecha de parto, pérdida de la preñez (si o no), incidencia de anestro (si o no) y fecha del primer servicio. Para las variables respuesta incidencia de anestro y pérdida de preñez, se consideraron variables explicativas al tambo y nú- mero de parición; los datos se analizaron por regresión logística utilizando Proc Genmod de SAS System. Para evaluar el efecto del número de parición, el tambo y la incidencia de anestro sobre el intervalo parto primer servicio (variable respuesta), se realizó ANOVA factorial seguido del post-test de Bonferroni con el software antes mencionado. Se observó una mayor incidencia de anestro posparto en primíparas (10.5 vs 7%; P = 0.001), con un marcado efecto del tambo (Tambo 1 = 25.4%, Tambo 2 = 3.5%; P &lt;0.001) e interacción entre ambos factores (Tambo 1: Primíparas = 14.3% Multíparas = 25.4%; Tambo 2: Primíparas = 3.8%, Multíparas = 3.3%; P = 0.03). El intervalo parto primer servicio fue mayor para vacas en anestro (81.28 vs 70.54 días; P &lt; 0.001) y se detectó interacción entre las variables número de parición y tambo (Tambo 1: Primíparas = 78.99 días, Multíparas = 78.05 días; Tambo 2: Primíparas = 68.52días, Multíparas = 77.08 días; P = 0.001). La pérdida de preñez fue mayor para las primíparas (13.2% vs. 11.2%; P = 0.04) en ambos tambos (Tambo =16%, Tambo 2 = 10%; P &lt; 0.001), sin interacción entre ambos factores (P = 0.94). Nuestros resultados refuerzan la idea de que vacas de alta producción muestran mayor predisposición a sufrir anestro posparto e intervalos parto primer servicio más prolongado. Además, las pérdidas de preñez fueron más frecuentes en vacas primíparas y en el rodeo de mayor producción lecher

Neuropeptide Y regulates the leptin receptors in rat hypothalamic and pituitary explant cultures

The aim of this work was to investigate whether the expression of leptin receptors (OBR) in the hypothalamic–pituitary (HP) axis is regulated by the orexigenic neuropeptide Y (NPY) during ovulation. To this end, we performed in vitro assays, using cultures of both hypothalamic and anterior pituitary explants from immature rats primed with gonadotropins to induce ovulation. In hypothalamic explants, protein expression of both the long and short OBR isoforms was increased by the presence of NPY at 100–500 ng/ml and at 300–500 ng/ml, respectively. Similarly, in pituitary explants, protein expression of the long isoform was increased between 30 and 300 ng/ml while that of the short isoform was increased only at 300 ng/ml. When both tissues were incubated with NPY and BIBP3226, a specific antagonist of the NPY Y1 receptor subtype, the NPY-induced protein expression was totally reversed by the antagonist at almost every concentration assayed. However, this antagonist was not always capable of blocking the increase caused by the presence of NPY at transcript level. In conclusion, our results indicate that NPY is able to regulate the expression of both the long and the short isoforms of OBR in the HP axis, at least in part, through the NPY Y1 receptor. These results reinforce the fact that NPY and its NPY Y1 receptor play a critical role in reproduction by modulating leptin sensitivity.Fil: Di Yorio, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Bilbao, María Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Faletti, Alicia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentin

Differential effects of leptin on ovarian metalloproteinases and their tissue inhibitors between in vivo and in vitro studies

In this study, we investigated the effect of leptin on the ovarian metalloproteinase system in the rat during the ovulatory process. Ovulation was induced in immature rats primed with gonadotropins. In both in vitro and in vivo experiments, we measured i) the protein expression of the ovarian metalloproteinases (matrix metalloproteinases, MMPs) and their tissue inhibitors (TIMPs) by western blot; ii) the gelatinase activity of the ovarian MMPs by zymography; and iii) the inhibitory action of TIMPs by reverse zymography. Using cultures of ovarian explants, leptin increased the activity but not the protein expression of MMP-2 and MMP-9 in both culture medium and ovarian tissue, and the protein expression of TIMPs, without a higher inhibitory action of the gelatinase activity. These results suggest either that the increase in TIMP proteins was not sufficient or that the inhibitory actions of TIMPs were impaired to suppress the MMP activity when the ovaries were directly exposed to leptin. To study the in vivo effect, rats received an acute treatment with high doses of leptin to inhibit ovulation. This treatment increased the expression of both the latent and the active forms of MMP-2 but did not result in a greater activity of MMP-2. In addition, the inhibitory action of TIMP-2 was also increased by this treatment. These results suggest that the administration of high doses of leptin could be regulating the follicle wall degradation, at least in part, by increasing the action of the ovarian TIMP-2 as a result of an extraovarian mechanism or signaling pathway.Fil: Bilbao, María Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Di Yorio, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Faletti, Alicia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentin

Different levels of leptin regulate different target enzymes involved in progesterone synthesis

Objective: To study the effects of different doses of leptin on the expression of proteins involved in P synthesis, such as steroidogenic acute regulatory protein (StAR), cytochrome P450 side chain cleavage (P450scc), and 3β-hydroxysteroid dehydrogenase (3βHSD). Design: Experimental studies. Setting: Research laboratory. Animal(s): Immature rats primed with gonadotropins to induce ovulation. Intervention(s): In vivo studies: rats received either an acute or daily treatment with leptin. In vitro studies: ovarian explants were cultured in the absence or presence of leptin (0.3–500 ng/mL). Main Outcome Measure(s): The expression of both messenger RNA and protein of StAR, P450scc, and 3βHSD were measured by reverse transcription-polymerase chain reaction (PCR) and Western blot, respectively. Result(s): The acute treatment with leptin, which inhibits the ovulatory process, caused a significant reduction in the ovarian expression of P450scc without changes in StAR or 3βHSD. In contrast, the daily treatment, which induces the ovulatory process, showed an increased expression of the ovarian 3βHSD protein, without differences in the other proteins measured. We also found that leptin increased the protein of both P450scc and 3βHSD at physiological levels and inhibited both messenger RNA and protein of 3βHSD at higher concentrations. Conclusion(s): The results indicate that 1) leptin is able to regulate the expression of the 3βHSD protein in a dose-dependent manner; and 2) leptin seems to exert its dual effects on P synthesis on different targets in a dose-dependent manner.Fil: Bilbao, María Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Di Yorio, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Faletti, Alicia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin

Impact of postpartum diseases on culling prior to first service and reproductive performance in dairy cows

Aproximadamente la mitad de las vacas lecheras sufre enfermedades asociadas al parto que afectan la eficiencia reproductiva. Se estudiaron 2.364 lactancias para evaluar el impacto de la enfermedad dentro de los 21 días posparto (en conjunto e individualmente) sobre el rechazo previo al primer servicio, el porcentaje de concepción a primer servicio y las pérdidas entre 35 y 100 días de gestación. El 4,95% de las vacas sanas y 15,95% de las enfermas fueron rechazadas previo al primer servicio (RPC=6,68; P≤0,0001). El rechazo fue 8,93% en vacas con metritis (RPC=6,33; P≤0,0001) y 19,12% en vacas con cetosis (RPC=6,84; P=0,001). El porcentaje de concepción en sanas fue 36,16% y en enfermas 30,12% (RPC=0,75; P=0,052). El porcentaje de concepción en vacas con metritis fue 29,04% (RPC=0,71; P=0,084) y con cetosis 30,49% (RPC=0,59; P=0,068). Las pérdidas de gestación en sanas fueron 11,29% y en enfermas 14,73% (RPC=0,77; P=0,54). Las enfermedades asociadas al parto, tanto en conjunto como metritis y cetosis individualmente, incrementaron el rechazo previo al primer servicio, disminuyeron la concepción, pero no afectaron las pérdidas de gestación.Around half of dairy cows suffer from diseases associated with parturition that affect reproductive efficiency. A total of 2,364 lactations were studied to assess the impact of disease within 21 days postpartum (combined and individually) on culling prior to first service, conception to first service, and pregnancy losses from 35 to 100 days. In healthy cows, culling prior to first service was 4.95% and in sick cows it was 15.95% (OR=6.68; P≤0.0001). Culling was 8.93% in cows with metritis (OR=6.33; P≤0.0001) and 19.12% in cows with ketosis (OR=6.84; P=0.001). In healthy cows, conception rate was 36.16% and in sick cows was 30.12% (OR=0.75; P=0.052). Conception rate was 29.04% in cows with metritis (OR=0.71; P=0.084) and 30.49% in cows with ketosis (OR=0.59; P=0.068). Pregnancy losses in healthy cows were 11.29% and in sick cows were 14.73% (OR=0.77; P=0.54). Diseases associated with parturition combined or metritis and ketosis individually, increased culling prior to first service, decreased conception, but did not affect pregnancy losses.Fil: Reumann, Alicia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Universidad Nacional de Rio Negro. Sede Alto Valle. Escuela de Veterinaria y Produccion Agroindustrial.; ArgentinaFil: Bilbao, María Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Yaful, Graciela Noemi. Universidad Nacional de Rio Negro. Sede Alto Valle. Escuela de Veterinaria y Produccion Agroindustrial.; ArgentinaFil: Blanco, Carlos. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Bartolome, Julian. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentin

Ovarian signaling pathways regulated by leptin during the ovulatory process

Leptin, a protein secreted by different tissues, is able to exert both stimulatory and inhibitory effects on the ovulatory process. Thus, we investigated whether these opposite effects involve changes in the ovarian signalling pathways in response to different levels of leptin. To this end, we performed both in vivo and in vitro assays using immature rats primed with gonadotrophins to induce ovulation. The acute treatment with leptin, which inhibits the ovulatory process, caused a significant decrease in the phosphorylation of both STAT3 and ERK1/2 and a simultaneous increase in suppressors of cytokine signalling 3 (SOCS3) protein. However, daily administration of a low dose of leptin, which induces the ovulatory process, showed increased phosphorylation of both STAT3 and ERK1/2 and a decreased expression of SOCS3 protein. Using ovarian explant cultures, we also found that leptin was able to activate both STAT3 and ERK1/2 at 10 ng/ml but only STAT3 at 300–500 ng/ml. In addition, at 100–300 ng/ml, leptin increased protein but not mRNA expression of SOCS3. The addition of specific inhibitors of JAK/STAT and MAPK signalling pathways suppressed both the increase and the decrease in leptin-induced progesterone secretion. These results indicate that i) different levels of leptin are able to regulate STAT3, ERK1/2 and SOCS3 at both intra- and extra-ovarian level and that ii) the dual action of leptin on steroidogenesis seems to occur, at least in part, through both the ERK and STAT cascades.Fil: Di Yorio, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Bilbao, María Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Biagini Majorel, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Faletti, Alicia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos; Argentin

Prosomeric Hypothalamic Distribution of Tyrosine Hydroxylase Positive Cells in Adolescent Rats

Most of the studies on neurochemical mapping, connectivity, and physiology in the hypothalamic region were carried out in rats and under the columnar morphologic paradigm. According to the columnar model, the entire hypothalamic region lies ventrally within the diencephalon, which includes preoptic, anterior, tuberal, and mamillary anteroposterior regions, and sometimes identifying dorsal, intermediate, and ventral hypothalamic partitions. This model is weak in providing little or no experimentally corroborated causal explanation of such subdivisions. In contrast, the modern prosomeric model uses different axial assumptions based on the parallel courses of the brain floor, alar-basal boundary, and brain roof (all causally explained). This model also postulates that the hypothalamus and telencephalon jointly form the secondary prosencephalon, separately from and rostral to the diencephalon proper. The hypothalamus is divided into two neuromeric (transverse) parts called peduncular and terminal hypothalamus (PHy and THy). The classic anteroposterior (AP) divisions of the columnar hypothalamus are rather seen as dorsoventral subdivisions of the hypothalamic alar and basal plates. In this study, we offered a prosomeric immunohistochemical mapping in the rat of hypothalamic cells expressing tyrosine hydroxylase (TH), which is the enzyme that catalyzes the conversion of L-tyrosine to levodopa (L-DOPA) and a precursor of dopamine. This mapping was also combined with markers for diverse hypothalamic nuclei [agouti-related peptide (Agrp), arginine vasopressin (Avp), cocaine and amphetamine-regulated transcript (Cart), corticotropin releasing Hormone (Crh), melanin concentrating hormone (Mch), neuropeptide Y (Npy), oxytocin/neurophysin I (Oxt), proopiomelanocortin (Pomc), somatostatin (Sst), tyrosine hidroxilase (Th), and thyrotropin releasing hormone (Trh)]. TH-positive cells are particularly abundant within the periventricular stratum of the paraventricular and subparaventricular alar domains. In the tuberal region, most labeled cells are found in the acroterminal arcuate nucleus and in the terminal periventricular stratum. The dorsal retrotuberal region (PHy) contains the A13 cell group of TH-positive cells. In addition, some TH cells appear in the perimamillary and retromamillary regions. The prosomeric model proved useful for determining the precise location of TH-positive cells relative to possible origins of morphogenetic signals, thus aiding potential causal explanation of position-related specification of this hypothalamic cell type.Fil: Bilbao, María Guillermina. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Garrigos, Daniel. Universidad de Murcia; EspañaFil: Martinez Morga, Marta. Universidad de Murcia; EspañaFil: Toval, Angel. Universidad de Murcia; EspañaFil: Kutsenko, Yevheniy. Universidad de Murcia; EspañaFil: Bautista, Rosario. Universidad de Murcia; EspañaFil: Barreda, Alberto. Universidad de Murcia; EspañaFil: Ribeiro Do Couto, Bruno. Universidad de Murcia; EspañaFil: Puelles, Luis. Universidad de Murcia; EspañaFil: Ferran, José Luis. Universidad de Murcia; Españ

Hormonal levels and semen parameters of Criollo breed stallions under intensive training

The stress associated with intensive training may reduce reproductive efficiency in Criollo stallions. The objective was to compare semen quality and cortisol, testosterone, and estradiol levels in Criollo stallions under training conditions with those of stallions under regular field conditions. Criollo breed stallions (n¼18) were evaluated from August 15th to October 30th. The Exercise group (ExG, n¼9) received one hour of exercise per day, and participated in competitions during the experimental period. The Control group (CoG, n¼9) neither exercise nor participated in competition. Before the initiation of the experiment, semen was collected by artificial vagina twice a day for 7 consecutive days to keep the stallions in daily sperm output (DSO). Every 15 days semen (2 separate ejaculates an hour apart) and serum samples (before and after exercise in ExG) were collected. Analysis of variance using repeated measures (SAS System) with stallions nested in treatments and day as repeated factor was used to evaluate the results. There was no effect of exercise in testosterone levels (pre-exercise: 0.58 0.06 ng/mL, post-exercise: 0.66 0.06 ng/mL, CoG: 0.50 0.06 ng/mL; P¼ 0.28) and estradiol levels (pre-exercise: 222.17 36.23 pg/mL, post-exercise: 228.84 36.23 pg/mL, CoG ¼ 231.91 36.08 pg/mL; P¼0.97). However, in the ExG cortisol level was higher after exercise (pre-exercise 59.96 4.58 nM/mL vs. posexercise 81.05 4.58 nM/mL) while in the CoG cortisol level was 59.80 4.57 nM/mL (P¼0.004). There was an effect of exercise on the following semen parameters: gel-free volume (ExG 41.46 6.1 ml vs. CoG 53.33 6.3 ml; P<0.001), sperm motility (ExG 47.8 2.53 % vs. CoG 63.56 2.5 %; P <0.0001), total number of sperm (ExG 8104.91 1267.16 x 106 vs. CoG 12124.16 1252.58 x 106 ; P¼ 0,0001), normal sperm morphology (ExG 60.03% 1,69 vs CoG 76.73% 1.67; P < 0.0001) and total number of morphologically normal and motile sperm (ExG 2277.65 564.2 x 106 vs. CoG 5730.54 557.3 x 106 ; P<0.001). No effect of exercise was found in color, pH, sperm concentration. The study showed that exercise under this experimental condition had a negative impact on seminal quality. Nevertheless, semen parameters remained within the normal ranges established for stallions.Fil: Rossetto, Liliana. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Farcey, Maria Florencia. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Chapero, Luisina Andrea. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Bilbao, María Guillermina. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; ArgentinaFil: Bartolome, Julian. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Miragaya, Marcelo. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigación y Tecnología en Reproducción Animal; Argentin