Abstract Reproductive biotechniques in the equine species have advanced in the last decade and horse breeders have started to question the possibilities of interfering in the determination of foal sex. The aim of the present study was to verify whether the variables mares and stallion’s age, side of the ovary containing the preovulatory follicle, preovulatory follicle diameter, time between breeding and ovulation, and ovulation inducing hormones influence the sex of the foal. A total of 259 reproductive cycles of 160 mares and 22 Thoroughbred stallions were used. Statistical analysis was performed using R software, including Pearson's chi-square test and logistic regression. Of the total foals born, 136 were males (52.51%) and 123 were females (47.49%). In mares that ovulated with -24h after ovulation induction, 104 foals (54.74%) were males and 86 (45.26%) were females, while in mares that ovulated with +24h, 32 foals (46.38%) were males and 37 (53.62%) were females. Stallions up to 15 years old had 44.14% (n=49) females and those over 15 years had 49.66% (n=73) females. The simple logistic regression model showed that mares and stallions under 15 years old, mares with ovulation time less than 24 hours and treated with Deslorelin had a higher probability of having male foals, but the Pearson's chi-square test showed that foals gender were not influenced by the variables studied. stallion s age diameter 25 16 2 used software Pearsons Pearson chisquare chi square born 13 52.51% 5251 52 51 (52.51% 12 47.49%. 4749 47.49% . 47 49 (47.49%) 24h h induction 10 54.74% 5474 54 74 (54.74% 8 45.26% 4526 45 26 (45.26% +24h 3 46.38% 4638 46 38 (46.38% 53.62% 5362 53 62 (53.62% 1 4414 44 14 44.14 n=49 n49 n (n=49 4966 66 49.66 n=73 n73 73 (n=73 studied 52.51 525 5 (52.51 474 47.49 4 (47.49% 54.74 547 7 (54.74 45.26 452 (45.26 46.38 463 (46.38 53.62 536 6 (53.62 441 44.1 n=4 n4 (n=4 496 49.6 n=7 n7 (n=7 52.5 (52.5 47.4 (47.49 54.7 (54.7 45.2 (45.2 46.3 (46.3 53.6 (53.6 44. n= (n= 49. 52. (52. 47. (47.4 54. (54. 45. (45. 46. (46. 53. (53. (n (52 (47. (54 (45 (46 (53 (5 (47 (4 (

SUMMARY: The equine placenta is a simple apposition of fetal and maternal tissues, becoming more complex with the formation of microcotyledons around days 75 and 100 of gestation. The present study aimed to describe the gross and microscopic morphology of early equine placenta. Embryonic/fetal membranes from thirty-seven mares were submitted to macroscopic description, light, scanning and transmission microscopy. Overall the gross characteristics of membranes were similar with already described for older stages. However, transmission electron microscopy evidenced high metabolic rate in chorion and allantois, and high secretion profile in amnion and even higher in yolk sac. Gene ontologies enrichment, using published data, pointed several common ontologies in allantoic and amniotic fluids, related to oxygen and iron transport, extracellular space and high-density lipoprotein receptor binding. Overall, the morphological and ontology enrichment could indicate allantois and amnion crosstalk.

RESUMEN: La placenta equina es una simple aposición de tejidos fetales y maternos, que se vuelve más compleja con la formación de microcotiledones alrededor de los días 75 y 100 de gestación. El presente estudio tuvo como objetivo describir la morfología macroscópica y microscópica de la placenta equina temprana. Las membranas embrionarias / fetales de treinta y siete yeguas fueron sometidas a descripción macroscópica, luz, escaneo y microscopía de transmisión. En general, las características generales de las membranas fueron similares a las ya descritas para las etapas más antiguas. Sin embargo, la microscopía electrónica de transmisión mostró una alta tasa metabólica en corion y alantoides, y un alto perfil de secreción en amnios e incluso mayor en el saco vitelino. El enriquecimiento de ontologías génicas, utilizando datos publicados, señaló varias ontologías comunes en fluidos alantoideos y amnióticos, relacionados con el transporte de oxígeno y hierro, espacio extracelular y unión a receptores de lipoproteínas de alta densidad. En general, el enriquecimiento morfológico y ontológico podría indicar alantoides y diafonía de amnios.

Resumo Dois experimentos foram realizados para verificar a viabilidade de diluentes para sêmen equino refrigerado. O objetivo do primeiro experimento foi verificar a eficiência do leite UHT integral e semidesnatado, comparado ao leite desnatado. Amostras foram analisadas a fresco e posteriormente diluídas em leite UHT integral, semidesnatado e desnatado. Foram realizados exames de motilidade espermática e vigor, CFDA/PI e HOST pós-diluição (0h), e no sêmen refrigerado a 5 ºC após 24 e 48 horas. Não houve diferença entre os três diluentes, quanto à motilidade espermática (p=0,9880), vigor (p=0,7249), CFDA/PI (p=0,3382) e HOST (p > 0,01). Houve uma diminuição na qualidade do sêmen, no decorrer do tempo (p < 0,01), independente do diluente utilizado. Pode-se afirmar que, na falta de leite UHT desnatado, o semidesnatado e o integral podem ser usados, uma vez que eles não provocam prejuízo na qualidade do sêmen refrigerado armazenado por até 48 horas. No segundo experimento, o objetivo foi verificar a eficácia do leite desnatado em comparação com diluentes comerciais (Botusemen® (BS) e Botusemen Special® (BSS)). Logo após a coleta do sêmen, as amostras foram diluídas com leite UHT desnatado (LD), Botusemen® (BS) e Botusemen Special®(BSS). A análise de sêmen seguiu o mesmo protocolo do primeiro experimento. As amostras de sêmen refrigeradas com BSS apresentaram HOST e CFDA/PI (p< 0,001) maiores nas 24h e 48 h o que indica que o diluente BSS promove aumento da longevidade dos espermatozoides em comparação com os outros analisados.

Abstract Two trials were performed to verify the viability of extenders equine cooled semen. The objective of the first trial was to verify the efficacy of whole and semi-skimmed UHT milk compared to skim milk. Fresh semen samples were analyzed and later diluted in UHT whole milk, semi skimmed and skimmed milk. Sperm motility and vigor, CFDA / PI and HOST tests were performed post-dilution (0h), and in semen cooled at 5oC after 24 and 48h. There was no difference between the 3 extenders, for sperm motility (p = 0.9880), vigor (p = 0.7249), CFDA / PI (p = 0.3882) and HOST (p> 0.01). There was a decrease in semen quality over time (p <0.01), regardless of the extender used. It can be stated that in the absence of skimmed UHT milk, semi-skimmed and whole milk can be used since they do not impair the quality of refrigerated semen stored for up to 48 hours. In the second trial the objective was to verify the efficacy of the skim milk compared to commercial extenders (Botusemen® (BS) and Botusemen Special® (BSS)). Soon after semen collection, the samples were diluted with UHT skim milk (LD), Botusemen® (BS) and Botusemen Special® (BSS). Semen analysis followed the same protocol as the first experiment. BSS-cooled semen showed higher HOST and CFDA / PI (p <0.001) in 24h and 48h indicating that BSS diluent promotes increased sperm longevity compared to the others analyzed.

ABSTRACT This study used path analysis to establish the direct, indirect, and total effects of body linear and angular measurements on subjective morphological scores of the 247 Criollo horses that participated in their most important performance event, Freio de Ouro, in 2012. Freio de Ouro is the only event of the Criollo breed that considers morphology. Measurements of wither height, thoracic girth, cannon bone girth, body length, metatarsus length, croup length, shoulder width, head length, neck length, and upper neck girth, and the angles of rump, shoulder, and hock were taken. These morphometric measurements collectively explained 83% of the variation in morphological score. The measurements with the greatest total effects on score were neck length (correlation coefficient = 0.2300), upper neck girth (0.2100), angle of rump (–0.1600), thoracic girth (0.1400), shoulder width (0.1400), body length (0.1100), croup length (0.1100), shoulder angle (–0.1100), and metatarsus length (0.1000). These results mean that these variables have the highest association with morphological evaluation by referees. This is the first scientific study of the correlation of morphological measurements with judge evaluation in Criollo horses.